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Sample records for delayed alternation task

  1. Retention performance of a learned delayed-alternation task after chemical lesions of the cats mediodorsal nucleus.

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    Markowitsch, H J

    1982-03-01

    The mediodorsal nucleus of the thalamus was lesioned in cats, which had learned a spatial delayed-alternation task. Lesions were carried out with kainic acid or ibotenic acid. From altogether 29 cats, 9 cats with bilateral and 6 cats with unilateral lesions of the mediodorsal nucleus together with a control group of 4 cats, were included in the final data analysis. Lesions in the operated cats destroyed variable portions of the mediodorsal nucleus. Consistently, however, neither the midline nuclei, situated next to the damaged mediodorsal nucleus, nor fiber tracts traversing or by-passing the mediodorsal nucleus, were damaged. Furthermore, remote lesion effects were not detected either in the diazepam-pretreated cats with kainic acid-induced lesions or in the ibotenic acid-lesioned animals. Cats injected with ibotenic acid at a concentration 8-fold higher than the kainic acid solution, showed smaller thalamic lesions than kainic acid-injected cats. A direct correlation was found between the extent of neuronal damage within the mediodorsal nucleus and the degree of the behavioral impairment. Cats with complete or almost complete bilateral lesions of the mediodorsal nucleus manifested severe deficits in retention of the delayed-alternation task, while cats with small, bilateral lesions of the mediodorsal nucleus or with unilateral lesions were impaired less severely or even not at all.

  2. In vivo polymerization of poly(3,4-ethylenedioxythiophene) in the living rat hippocampus does not cause a significant loss of performance in a delayed alternation task

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    Ouyang, Liangqi; Shaw, Crystal L.; Kuo, Chin-chen; Griffin, Amy L.; Martin, David C.

    2014-04-01

    After extended implantation times, traditional intracortical neural probes exhibit a foreign-body reaction characterized by a reactive glial sheath that has been associated with increased system impedance and signal deterioration. Previously, we have proposed that the local in vivo polymerization of an electronically and ionically conducting polymer, poly(3,4-ethylenedioxythiophene) (PEDOT), might help to rebuild charge transport pathways across the glial scar between the device and surrounding parenchyma (Richardson-Burns et al 2007 J. Neural Eng. 4 L6-13). The EDOT monomer can be delivered via a microcannula/electrode system into the brain tissue of living animals followed by direct electrochemical polymerization, using the electrode itself as a source of oxidative current. In this study, we investigated the long-term effect of local in vivo PEDOT deposition on hippocampal neural function and histology. Rodent subjects were trained on a hippocampus-dependent task, delayed alternation (DA), and implanted with the microcannula/electrode system in the hippocampus. The animals were divided into four groups with different delay times between the initial surgery and the electrochemical polymerization: (1) control (no polymerization), (2) immediate (polymerization within 5 min of device implantation), (3) early (polymerization within 3-4 weeks after implantation) and (4) late (polymerization 7-8 weeks after polymerization). System impedance at 1 kHz was recorded and the tissue reactions were evaluated by immunohistochemistry. We found that under our deposition conditions, PEDOT typically grew at the tip of the electrode, forming an ˜500 µm cloud in the tissue. This is much larger than the typical width of the glial scar (˜150 µm). After polymerization, the impedance amplitude near the neurologically important frequency of 1 kHz dropped for all the groups; however, there was a time window of 3-4 weeks for an optimal decrease in impedance. For all surgery

  3. Traumatic and alternating delayed intracranial hematomas

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    Lesoin, F.; Redford, H.; Jomin, M.; Viaud, C.; Pruvo, J.

    1984-11-01

    Repeat computed tomography has enabled us to confirm the concept of delayed hematomas. With this in mind we report two cases of alternating, post-traumatic intracranial hematomas; confirming also the role of tamponade after surgical removal of an intracranial hematoma.

  4. The Effects of Delay of Feedback on a Delayed Concept Formation Transfer Task.

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    Schroth, Marvin L.

    1992-01-01

    Delay and completeness of verbal information feedback were investigated within a transfer of learning paradigm involving concept formation. An experiment with 192 undergraduates indicates that, although delay of feedback (up to 30 seconds) slows speed of learning on the initial task, it has positive effects on the transfer task. (SLD)

  5. Remote Task-level Commanding of Centaur over Time Delay

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    Schreckenghost, Debra; Ngo, Tam; Burridge, Robert; Wang, Lui; Izygon, Michel

    2008-01-01

    Remote operation of robots on the lunar surface by ground controllers poses unique human-robot interaction challenges due to time delay and constrained bandwidth. One strategy for addressing these challenges is to provide task-level commanding of robots by a ground controller. Decision-support tools are being developed at JSC for remote task-level commanding over time-delay. The approach is to provide ground procedures that guide a controller when executing task-level command sequences and aid awareness of the state of command execution in the robot. This approach is being evaluated using the Centaur robot at JSC. The Centaur Central Commander provides a task-level command interface that executes on the robot side of the delay. Decision support tools have been developed for a human Supervisor in the JSC Cockpit to use when interacting with the Centaur Central Commander. Commands to the Central Commander are defined as instructions in a procedure. Sequences of these instructions are grouped into procedures for the Cockpit Supervisor. When a Supervisor is ready to perform a task, a procedure is loaded into the decision support tool. From this tool, the Supervisor can view command sequences and dispatch individual commands to Centaur. Commands are queued for execution on the robot side of the delay. Reliable command sequences can be dispatched automatically upon approval by the Supervisor. The decision support tool provides the Supervisor with feedback about which commands are waiting for execution and which commands have finished. It also informs the Supervisor when a command fails to have its intended effect. Cockpit procedures are defined using the Procedure Representation Language (PRL) developed at JSC for mission operations. The decision support tool is based on a Procedure Sequencer and multi-agent software developed for human-robot interaction. In this paper the approach for remote task-level commanding of robots is described and the results of the evaluation

  6. Bayesian inference underlies the contraction bias in delayed comparison tasks.

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    Paymon Ashourian

    Full Text Available Delayed comparison tasks are widely used in the study of working memory and perception in psychology and neuroscience. It has long been known, however, that decisions in these tasks are biased. When the two stimuli in a delayed comparison trial are small in magnitude, subjects tend to report that the first stimulus is larger than the second stimulus. In contrast, subjects tend to report that the second stimulus is larger than the first when the stimuli are relatively large. Here we study the computational principles underlying this bias, also known as the contraction bias. We propose that the contraction bias results from a Bayesian computation in which a noisy representation of a magnitude is combined with a-priori information about the distribution of magnitudes to optimize performance. We test our hypothesis on choice behavior in a visual delayed comparison experiment by studying the effect of (i changing the prior distribution and (ii changing the uncertainty in the memorized stimulus. We show that choice behavior in both manipulations is consistent with the performance of an observer who uses a Bayesian inference in order to improve performance. Moreover, our results suggest that the contraction bias arises during memory retrieval/decision making and not during memory encoding. These results support the notion that the contraction bias illusion can be understood as resulting from optimality considerations.

  7. Delays and user performance in human-computer-network interaction tasks.

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    Caldwell, Barrett S; Wang, Enlie

    2009-12-01

    This article describes a series of studies conducted to examine factors affecting user perceptions, responses, and tolerance for network-based computer delays affecting distributed human-computer-network interaction (HCNI) tasks. HCNI tasks, even with increasing computing and network bandwidth capabilities, are still affected by human perceptions of delay and appropriate waiting times for information flow latencies. Conducted were 6 laboratory studies with university participants in China (Preliminary Experiments 1 through 3) and the United States (Experiments 4 through 6) to examine users' perceptions of elapsed time, effect of perceived network task performance partners on delay tolerance, and expectations of appropriate delays based on task, situation, and network conditions. Results across the six experiments indicate that users' delay tolerance and estimated delay were affected by multiple task and expectation factors, including task complexity and importance, situation urgency and time availability, file size, and network bandwidth capacity. Results also suggest a range of user strategies for incorporating delay tolerance in task planning and performance. HCNI user experience is influenced by combinations of task requirements, constraints, and understandings of system performance; tolerance is a nonlinear function of time constraint ratios or decay. Appropriate user interface tools providing delay feedback information can help modify user expectations and delay tolerance. These tools are especially valuable when delay conditions exceed a few seconds or when task constraints and system demands are high. Interface designs for HCNI tasks should consider assistant-style presentations of delay feedback, information freshness, and network characteristics. Assistants should also gather awareness of user time constraints.

  8. A delay discounting task produces a greater likelihood of waiting than a deferred gratification task.

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    Young, Michael E; McCoy, Anthony W

    2015-01-01

    A first-person-shooter video game was adapted for the study of choice between smaller sooner and larger later outcomes to compare the behavioral patterns produced by deferred gratification (DG) and delay discounting (DD) tasks. Participants played a game in which they could either fire their weapon sooner and do a small amount of damage or wait a few seconds to fire their weapon and do a larger amount of damage. For the DD task, a failure to fire within one second committed the player to waiting for the larger later outcome thus removing the opportunity to defect during the delay that is present in the DG task. The incentive structure changed multiple times during game play so that at times the optimal decision was to choose the smaller sooner outcome whereas at other times the optimal decision was to wait for the larger later outcome. Players assigned to the DD task showed a greater tendency to wait and lower sensitivity to the changing incentives.

  9. Training Tolerance to Delay Using the Escalating Interest Task.

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    Rung, Jillian M; Young, Michael E

    2014-09-01

    The present study examined the lasting effects of exposure to reinforcement that increased in magnitude as a function of time between responses in a first-person shooter video game preparation of the escalating interest task. When reinforcement density increased as a function of time, it encouraged participants to wait longer between responses (shots of a weapon). Participants exposed to such contingencies waited significantly longer to fire their weapons than participants who were exposed to linear growth, where long inter-response times were not differentially reinforced. Those with experience in conditions where reinforcement density increased as a function of time showed persistently longer wait times when the contingencies changed in the latter portion of the game where the disincentive to fire quickly was removed. The potential utility of such contingencies for training tolerance to delay of reinforcement and the broader implications of training self-control are discussed.

  10. Role of Delay of Feedback on Subsequent Pattern Recognition Transfer Tasks.

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    Schroth, Marvin L.; Lund, Elissa

    1993-01-01

    Two experiments with 100 undergraduates investigated effects of delay of feedback on immediate and delayed transfer tasks involving different pattern recognition strategies. Delay of feedback resulted in greater retention of the concepts underlying construction of the different patterns in all transfer tasks. Results support the Kulhavy-Anderson…

  11. How do African grey parrots (Psittacus erithacus) perform on a delay of gratification task?

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    Vick, Sarah-Jane; Bovet, Dalila; Anderson, James R

    2010-03-01

    Humans and other animals often find it difficult to choose a delayed reward over an immediate one, even when the delay leads to increased pay-offs. Using a visible incremental reward procedure, we tested the ability of three grey parrots to maintain delay of gratification for an increasingly valuable food pay-off. Up to five sunflower seeds were placed within the parrot's reach, one at a time, at a rate of one seed per second. When the parrot took a seed the trial was ended and the birds consumed the accumulated seeds. Parrots were first tested in daily sessions of ten trials and then with single daily trials. For multiple trial sessions, all three parrots showed some limited improvement across 30 sessions. For single trial sessions, only one parrot showed any increase in seed acquisition across trials. This parrot was also able to consistently obtain two or more seeds per trial (across both multiple and single trial conditions) but was unable to able to wait 5 s to obtain the maximum number of seeds. This parrot was also tested on a slower rate of seed presentation, and this significantly reduced her mean seed acquisition in both multiple and single trial conditions, suggesting that both value of reward available and delay duration impact upon self-control. Further manipulation of both the visibility and proximity of seeds during delay maintenance had little impact upon tolerance of delays for both parrots tested in this condition. This task demanded not just a choice of delayed reward but the maintenance of delayed gratification and was clearly difficult for the parrots to learn; additional training or alternative paradigms are required to better understand the capacity for self-control in this and other species.

  12. Task Engagement and Escape Maintained Challenging Behavior: Differential Effects of General and Explicit Cues when Implementing a Signaled Delay in the Delivery of Reinforcement

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    Reichle, Joe; Johnson, LeAnne; Monn, Emily; Harris, Michael

    2010-01-01

    This study was designed to evaluate the effects of explicit and general delay cues when implementing a tolerance for a delay in the delivery of a reinforcement procedure to increase task engagement and decrease escape maintained challenging behavior. Two preschool children with autism participated in an alternating treatments design with changing…

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

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    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.

  14. Retention and relearning of spatial delayed alternation in rats after ablation of the prefrontal or total non-prefrontal isocortex

    DEFF Research Database (Denmark)

    Wörtwein, Gitta; Mogensen, Jesper; Divac, Ivan

    1994-01-01

    Neurobiologi, præfrontal cortex, delayed alternation, funktionel genopretning, neocortex, rotte......Neurobiologi, præfrontal cortex, delayed alternation, funktionel genopretning, neocortex, rotte...

  15. Rats value time differently on equivalent foraging and delay-discounting tasks.

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    Carter, Evan C; Redish, A David

    2016-09-01

    All organisms have to consider consequences that vary through time. Theories explaining how animals handle intertemporal choice include delay-discounting models, in which the value of future rewards is discounted by the delay until receipt, and foraging models, which predict that decision-makers maximize rate of reward. We measured the behavior of rats on a 2-option delay-discounting task and a stay/go foraging task that were equivalent for rate of reward and physical demand. Despite the highly shared features of the tasks, rats were willing to wait much longer on the foraging task than on the delay-discounting task. Moreover, choice performance by rats was less optimal in terms of total reward received on the foraging task compared to the delay-discounting task. We applied a suite of intertemporal choice models to the data but found that we needed a novel model incorporating interactions of decision-making systems to successfully explain behavior. Our findings (a) highlight the importance of factors that historically have been seen as irrelevant and (b) indicate the inadequacy of current general theories of intertemporal choice. (PsycINFO Database Record

  16. Is it really self-control? Examining the predictive power of the delay of gratification task.

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    Duckworth, Angela L; Tsukayama, Eli; Kirby, Teri A

    2013-07-01

    This investigation tests whether the predictive power of the delay of gratification task (colloquially known as the "marshmallow test") derives from its assessment of self-control or of theoretically unrelated traits. Among 56 school-age children in Study 1, delay time was associated with concurrent teacher ratings of self-control and Big Five conscientiousness-but not with other personality traits, intelligence, or reward-related impulses. Likewise, among 966 preschool children in Study 2, delay time was consistently associated with concurrent parent and caregiver ratings of self-control but not with reward-related impulses. While delay time in Study 2 was also related to concurrently measured intelligence, predictive relations with academic, health, and social outcomes in adolescence were more consistently explained by ratings of effortful control. Collectively, these findings suggest that delay task performance may be influenced by extraneous traits, but its predictive power derives primarily from its assessment of self-control.

  17. Chronic infusions of GABA into the medial frontal cortex of the rat induce a reversible delayed spatial alternation deficit.

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    Di Scala, G; Meneses, S; Brailowsky, S

    1990-10-30

    The effects of bilateral infusions of GABA into the medial frontal cortex of the rat were studied in a delayed spatial alternation task. It was found that GABA (500 mM, 1 microliter/h during 7 days) impaired the performance of the rats in the previously learned task. Upon interruption of the treatment, the animals rapidly recovered normal performance scores. The results show that GABA infusions produce functional deficits similar to those produced by lesions of the frontal cortex. Moreover, the deficits are reversible upon interruption of the treatment. This technique may therefore be a useful tool for studying frontal lobe functions and the involvement of GABAergic mechanisms in cognitive processes.

  18. Task-specific modulation of human auditory evoked responses in a delayed-match-to-sample task

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    Feng eRong

    2011-05-01

    Full Text Available In this study, we focus our investigation on task-specific cognitive modulation of early cortical auditory processing in human cerebral cortex. During the experiments, we acquired whole-head magnetoencephalography (MEG data while participants were performing an auditory delayed-match-to-sample (DMS task and associated control tasks. Using a spatial filtering beamformer technique to simultaneously estimate multiple source activities inside the human brain, we observed a significant DMS-specific suppression of the auditory evoked response to the second stimulus in a sound pair, with the center of the effect being located in the vicinity of the left auditory cortex. For the right auditory cortex, a non-invariant suppression effect was observed in both DMS and control tasks. Furthermore, analysis of coherence revealed a beta band (12 ~ 20 Hz DMS-specific enhanced functional interaction between the sources in left auditory cortex and those in left inferior frontal gyrus, which has been shown to involve in short-term memory processing during the delay period of DMS task. Our findings support the view that early evoked cortical responses to incoming acoustic stimuli can be modulated by task-specific cognitive functions by means of frontal-temporal functional interactions.

  19. Delays without mistakes: response time and error distributions in dual-task.

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    Juan Esteban Kamienkowski

    Full Text Available BACKGROUND: When two tasks are presented within a short interval, a delay in the execution of the second task has been systematically observed. Psychological theorizing has argued that while sensory and motor operations can proceed in parallel, the coordination between these modules establishes a processing bottleneck. This model predicts that the timing but not the characteristics (duration, precision, variability... of each processing stage are affected by interference. Thus, a critical test to this hypothesis is to explore whether the quality of the decision is unaffected by a concurrent task. METHODOLOGY/PRINCIPAL FINDINGS: In number comparison--as in most decision comparison tasks with a scalar measure of the evidence--the extent to which two stimuli can be discriminated is determined by their ratio, referred as the Weber fraction. We investigated performance in a rapid succession of two non-symbolic comparison tasks (number comparison and tone discrimination in which error rates in both tasks could be manipulated parametrically from chance to almost perfect. We observed that dual-task interference has a massive effect on RT but does not affect the error rates, or the distribution of errors as a function of the evidence. CONCLUSIONS/SIGNIFICANCE: Our results imply that while the decision process itself is delayed during multiple task execution, its workings are unaffected by task interference, providing strong evidence in favor of a sequential model of task execution.

  20. Decreased frontal, striatal and cerebellar activation in adults with ADHD during an adaptive delay discounting task.

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    Ortiz, Nick; Parsons, Aisling; Whelan, Robert; Brennan, Katie; Agan, Maria L F; O'Connell, Redmond; Bramham, Jessica; Garavan, Hugh

    2015-01-01

    An important characteristic of childhood attention-deficit/hyperactivity disorder (ADHD) is a bias towards small immediate versus larger delayed rewards, but it is not known if this symptom is also a feature of adult ADHD. A delay-discounting task was administered to participants with adult ADHD and a comparison group in conjunction with functional magnetic resonance imaging. Participants responded to a series of questions that required judgments between small sums of money available immediately and larger sums obtained after a temporal delay. Question parameters were adjusted by an adaptive algorithm designed to converge on each participant's discounting indifference point, an individual set point at which there is equal valuation of both choices. In all participants, robust task activation was observed in regions previously identified in functional imaging studies of delay discounting. However, adults with ADHD showed less task activation in a number of regions including the dorsolateral prefrontal cortex, superior frontal gyrus, anterior cingulate, caudate nucleus and declive of the cerebellum. Additionally, the degree to which a participant discounted delayed rewards was inversely related to task activation in the cerebellum. The results suggest that the bias towards immediate rewards in childhood ADHD may not persist behaviorally, but instead present in adulthood as alterations in frontostriatal and frontocerebellar networks.

  1. Sustained performance by common marmosets in a delayed matching to position task with variable stimulus presentations.

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    Yamazaki, Yumiko; Saiki, Masakado; Inada, Masayuki; Watanabe, Shigeru; Iriki, Atsushi

    2016-01-15

    Working memory is used to solve various cognitive problems by maintaining information for some time and then by refreshing this information after certain purposes are achieved. In the present study, we explored the ability of common marmosets to perform a delayed matching to position (DMTP) task in a controlled environment using operant conditioning. The DMTP task requires the subjects to respond to the sample stimulus and to select one of two comparison stimuli with a position matching that of the sample stimulus after a programmed delay period. Positional arrangement of the sample and comparison stimuli, which were quasi-randomly determined in each trial, was employed to prevent the subjects from using any strategies based on their own body positions or orientations. The delay intervals between presentations of the sample and comparison stimuli were fixed at 0.5 and 1s in the initial phases and were then varied between 5 intervals per delay set (e.g., 0.5, 1, 2, 4, and 8s) intermixed in a session. The longest delay interval within a set was gradually increased after the marmosets achieved the criterion of each task. The subjects were successfully trained in the procedure and showed accurate performance even following delays of more than 100 s. The response times in the trials suggested that they used different strategies depending on the delay interval length. Thus, the present study shows the robust ability of common marmosets in a task requiring positional memory, which is related to their foraging strategy observed in the wild.

  2. Delay discounting task in pigs reveals response strategies related to dopamine metabolite.

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    Melotti, Luca; Thomsen, Liat Romme; Toscano, Michael J; Mendl, Michael; Held, Suzanne

    2013-08-15

    We developed a novel delay discounting task to investigate outcome impulsivity in pigs. As impulsivity can affect aggression, and might also relate to proactive and reactive coping styles, eight proactive (HR) and eight reactive (LR) pigs identified in a manual restraint test ("Backtest", after Bolhuis et al., 2003) were weaned and mixed in four pens of four unfamiliar pigs, so that each pen had two HR and two LR pigs, and aggression was scored in the 9h after mixing. In the delay discounting task, each pig chose between two levers, one always delivering a small immediate reward, the other a large delayed reward with daily increasing delays, impulsive individuals being the ones discounting the value of the large reward quicker. Two novel strategies emerged: some pigs gradually switched their preference towards the small reward ('Switchers') as predicted, but others persistently preferred the large reward until they stopped making choices ('Omitters'). Outcome impulsivity itself was unrelated to these strategies, to urinary serotonin metabolite (5-HIAA) or dopamine metabolite (HVA) levels, aggression at weaning, or coping style. However, HVA was relatively higher in Omitters than Switchers, and positively correlated with behavioural measures of indecisiveness and frustration during choosing. The delay discounting task thus revealed two response strategies that seemed to be related to the activity of the dopamine system and might indicate a difference in execution, rather than outcome, impulsivity.

  3. An alternative approach to calculating Area-Under-the-Curve (AUC) in delay discounting research.

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    Borges, Allison M; Kuang, Jinyi; Milhorn, Hannah; Yi, Richard

    2016-09-01

    Applied to delay discounting data, Area-Under-the-Curve (AUC) provides an atheoretical index of the rate of delay discounting. The conventional method of calculating AUC, by summing the areas of the trapezoids formed by successive delay-indifference point pairings, does not account for the fact that most delay discounting tasks scale delay pseudoexponentially, that is, time intervals between delays typically get larger as delays get longer. This results in a disproportionate contribution of indifference points at long delays to the total AUC, with minimal contribution from indifference points at short delays. We propose two modifications that correct for this imbalance via a base-10 logarithmic transformation and an ordinal scaling transformation of delays. These newly proposed indices of discounting, AUClog d and AUCor d, address the limitation of AUC while preserving a primary strength (remaining atheoretical). Re-examination of previously published data provides empirical support for both AUClog d and AUCor d . Thus, we believe theoretical and empirical arguments favor these methods as the preferred atheoretical indices of delay discounting.

  4. Variation at work: alternations between physically and mentally demanding tasks in blue-collar occupations.

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    Jahncke, Helena; Hygge, Staffan; Mathiassen, Svend Erik; Hallman, David; Mixter, Susanna; Lyskov, Eugene

    2017-09-01

    The aims of this questionnaire study were to describe the occurrence and desired number of alternations between mental and physical tasks in industrial and non-industrial blue-collar work, and determine to which extent selected personal and occupational factors influence these conditions. On average, the 122 participating workers (55 females) reported to have close to four alternations per day between mental and physical tasks, and to desire more alternations than they actually had. They also expressed a general preference for performing a physical task after a mental task and vice versa. In univariate regression models, the desired change in task alternations was significantly associated with gender, age, occupation, years with current work tasks and perceived job control, while occupation was the only significant determinant in a multiple regression model including all factors. Our results suggest that alternations between productive physical and mental tasks could be a viable option in future job rotation. Practitioner Summary: We addressed attitudes among blue-collar workers to alternations between physically and mentally demanding tasks. More alternations were desired than those occurring in the job, and workers preferred performing a physical task after a mental and vice versa. Alternating physical and mental tasks could, thus, be a viable option in job rotation.

  5. Shallow discounting of delayed cocaine by male rhesus monkeys when immediate food is the choice alternative.

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    Huskinson, Sally L; Myerson, Joel; Green, Leonard; Rowlett, James K; Woolverton, William L; Freeman, Kevin B

    2016-12-01

    Huskinson et al. (2015) recently examined delay discounting in monkeys choosing between an immediate drug (cocaine) reinforcer and a delayed nondrug (food) reinforcer. The present experiment examined the reverse situation: choice between immediate nondrug (food) and delayed drug (cocaine) reinforcers. Whereas the former choice situation exemplifies drug abuse from a delay-discounting perspective, our interest in the latter choice situation is derived from the observation that drug abusers, who characteristically are associated with impulsive choice, typically must devote considerable time to procuring drugs, often at the expense of immediate nondrug alternatives. Accordingly, we analyzed 3 male rhesus monkeys' choices between immediate food and delayed cocaine (0.1 and 0.2 mg/kg/injection) using a hyperbolic model that allowed us to compare discounting rates between qualitatively different reinforcers. Choice of immediate food increased with food amount, and choice functions generally shifted leftward as delay to cocaine increased, indicating a decrease in the subjective value of cocaine. Compared with our previous delay-discounting experiment with immediate cocaine versus delayed food, both doses of delayed cocaine were discounted at a shallow rate. The present results demonstrate that rhesus monkeys will tolerate relatively long delays in an immediate-food versus delayed-drug situation, suggesting that in intertemporal choices between cocaine and food, the subjective value of cocaine is less affected by the delay until reinforcement than is the subjective value of delayed food. More generally, the present findings suggest that although drug abusers may choose impulsively when immediate drug reinforcement is available, they exercise self-control in the acquisition of a highly preferred, delayed drug reinforcer. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  6. Initial judgment task and delay of the final validity-rating task moderate the truth effect.

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    Nadarevic, Lena; Erdfelder, Edgar

    2014-01-01

    Repeatedly seen or heard statements are typically judged to be more valid than statements one has never encountered before. This phenomenon has been referred to as the truth effect. We conducted two experiments to assess the plasticity of the truth effect under different contextual conditions. Surprisingly, we did not find a truth effect in the typical judgment design when using a ten minutes interval between statement repetitions. However, we replicated the truth effect when changing the judgment task at initial statement exposure or when using an interval of one week rather than ten minutes. Because none of the current truth effect theories can fully account for these context effects, we conclude that the cognitive processes underlying truth judgments are more complex than has hitherto been assumed. To close the theoretical gap, we propose a revised fluency attribution hypothesis as a possible explanation of our findings. Copyright © 2013 Elsevier Inc. All rights reserved.

  7. Comparison of Motor Inhibition in Variants of the Instructed-Delay Choice Reaction Time Task.

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    Quoilin, Caroline; Lambert, Julien; Jacob, Benvenuto; Klein, Pierre-Alexandre; Duque, Julie

    2016-01-01

    Using instructed-delay choice reaction time (RT) paradigms, many previous studies have shown that the motor system is transiently inhibited during response preparation: motor-evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS) over the primary motor cortex are typically suppressed during the delay period. This effect has been observed in both selected and non-selected effectors, although MEP changes in selected effectors have been more inconsistent across task versions. Here, we compared changes in MEP amplitudes in three different variants of an instructed-delay choice RT task. All variants required participants to choose between left and right index finger movements but the responses were either provided "in the air" (Variant 1), on a regular keyboard (Variant 2), or on a response device designed to control from premature responses (Variant 3). The task variants also differed according to the visual layout (more concrete in Variant 3) and depending on whether participants received a feedback of their performance (absent in Variant 1). Behavior was globally comparable between the three variants of the task although the propensity to respond prematurely was highest in Variant 2 and lowest in Variant 3. MEPs elicited in a non-selected hand were similarly suppressed in the three variants of the task. However, significant differences emerged when considering MEPs elicited in the selected hand: these MEPs were suppressed in Variants 1 and 3 whereas they were often facilitated in Variant 2, especially in the right dominant hand. In conclusion, MEPs elicited in selected muscles seem to be more sensitive to small variations to the task design than those recorded in non-selected effectors, probably because they reflect a complex combination of inhibitory and facilitatory influences on the motor output system. Finally, the use of a standard keyboard seems to be particularly inappropriate because it encourages participants to respond promptly with no

  8. Task-dependent modulation of primary afferent depolarization in cervical spinal cord of monkeys performing an instructed delay task.

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    Seki, Kazuhiko; Perlmutter, Steve I; Fetz, Eberhard E

    2009-07-01

    Task-dependent modulation of primary afferent depolarization (PAD) was studied in the cervical spinal cord of two monkeys performing a wrist flexion and extension task with an instructed delay period. We implanted two nerve cuff electrodes on proximal and distal parts of the superficial radial nerve (SR) and a recording chamber over a hemi-laminectomy in the lower cervical vertebrae. Antidromic volleys (ADVs) in the SR were evoked by intraspinal microstimuli (ISMS, 3-10 Hz, 3-30 microA) applied through a tungsten microelectrode, and the area of each ADV was measured. In total, 434 ADVs were evoked by ISMS in two monkeys, with onset latency consistently shorter in the proximal than distal cuffs. Estimated conduction velocity suggest that most ADVs were caused by action potentials in cutaneous fibers originating from low-threshold tactile receptors. Modulation of the size of ADVs as a function of the task was examined in 281 ADVs induced by ISMS applied at 78 different intraspinal sites. The ADVs were significantly facilitated during active movement in both flexion and extension (Pmodulation of PAD. This facilitation started 400-900 ms before the onset of EMG activity. Such pre-EMG modulation is hard to explain by movement-induced reafference and probably is associated with descending motor commands.

  9. True-time delay by slow light in a semiconductor waveguide with alternating amplifying and absorbing sections

    DEFF Research Database (Denmark)

    Öhman, Filip; Mørk, Jesper

    2006-01-01

    Modeling of slow light in a semiconductor waveguide with alternating gain and absorption sections demonstrate an increase in time delay by concatenating segments. A true-time delay is predicted over a large bandwidth at high frequency.......Modeling of slow light in a semiconductor waveguide with alternating gain and absorption sections demonstrate an increase in time delay by concatenating segments. A true-time delay is predicted over a large bandwidth at high frequency....

  10. Anxious Individuals Are Impulsive Decision-Makers in the Delay Discounting Task: An ERP Study.

    Science.gov (United States)

    Xia, Lisheng; Gu, Ruolei; Zhang, Dandan; Luo, Yuejia

    2017-01-01

    Impulsivity, which is linked to a wide range of psychiatric disorders, is often characterized by a preference for immediate but smaller rewards over delayed but larger rewards. However, debate exists on the relationship between anxiety and impulsivity. Here we use event-related potential (ERP) components as biomarkers in the temporal discounting task to examine the effect of anxiety on inter-temporal decision-making. Our behavioral results indicated that the high trait anxiety (HTA) group made significantly more immediate choices than the low trait anxiety (LTA) group. Compared with the LTA group, shorter response time was associated with immediate rewards in the HTA group. Furthermore, previous studies have demonstrated three ERP components that are associated with impulsivity and/or delay discounting. First, the N1 is an early sensory component involved in selective attention and attention processing for goal-directed actions. Second, the reward positivity (RewP) reflects reward-related dopaminergic activity and encodes reward values. Third, the P3 is regarded as a measure of motivational significance in the decision-making literature. Accordingly, this study found in the immediate-option-evoked ERPs that the HTA group had a larger N1 than the LTA group did. For the delayed-option-evoked ERPs, the HTA group had larger N1 and RewP for the immediate choice than the LTA group did, while the LTA group had a larger P3 for the delayed choice than the HTA group did. These results support the notion that anxiety individuals are impulsive decision-makers in the Delay Discounting Task.

  11. Anxious Individuals Are Impulsive Decision-Makers in the Delay Discounting Task: An ERP Study

    Science.gov (United States)

    Xia, Lisheng; Gu, Ruolei; Zhang, Dandan; Luo, Yuejia

    2017-01-01

    Impulsivity, which is linked to a wide range of psychiatric disorders, is often characterized by a preference for immediate but smaller rewards over delayed but larger rewards. However, debate exists on the relationship between anxiety and impulsivity. Here we use event-related potential (ERP) components as biomarkers in the temporal discounting task to examine the effect of anxiety on inter-temporal decision-making. Our behavioral results indicated that the high trait anxiety (HTA) group made significantly more immediate choices than the low trait anxiety (LTA) group. Compared with the LTA group, shorter response time was associated with immediate rewards in the HTA group. Furthermore, previous studies have demonstrated three ERP components that are associated with impulsivity and/or delay discounting. First, the N1 is an early sensory component involved in selective attention and attention processing for goal-directed actions. Second, the reward positivity (RewP) reflects reward-related dopaminergic activity and encodes reward values. Third, the P3 is regarded as a measure of motivational significance in the decision-making literature. Accordingly, this study found in the immediate-option-evoked ERPs that the HTA group had a larger N1 than the LTA group did. For the delayed-option-evoked ERPs, the HTA group had larger N1 and RewP for the immediate choice than the LTA group did, while the LTA group had a larger P3 for the delayed choice than the HTA group did. These results support the notion that anxiety individuals are impulsive decision-makers in the Delay Discounting Task. PMID:28174528

  12. Adolescents' performance on delay and probability discounting tasks: contributions of age, intelligence, executive functioning, and self-reported externalizing behavior.

    Science.gov (United States)

    Olson, Elizabeth A; Hooper, Catalina J; Collins, Paul; Luciana, Monica

    2007-11-01

    Healthy adolescents, ages 9-23, completed delay and probability discounting tasks and measures of verbal and nonverbal intelligence, executive functioning, and self-reported internalizing and externalizing behavior. Delay but not probability discounting decreased with age. Delay discounting was also associated with verbal intelligence and Go-NoGo and Iowa Gambling Task performance. Probability discounting was associated only with externalizing behavior. Findings conform to an accumulation of evidence that while delay and probability discounting may have some overlapping components, they also reflect some fundamentally different processes in this age group.

  13. Increased Delay Discounting on a Novel Real-Time Task among Girls, but not Boys, with ADHD

    Science.gov (United States)

    Rosch, Keri S.; Mostofsky, Stewart H.

    2016-01-01

    The aim of this study was to examine delay discounting in girls and boys with ADHD-Combined type (ADHD-C) relative to typically developing (TD) children on two tasks that differ in the extent to which the rewards and delays were experienced by participants. Children ages 8–12 years with ADHD-C (n = 65; 19 girls) and TD controls (n = 55; 15 girls) completed two delay discounting tasks involving a series of choices between smaller, immediate and larger, delayed rewards. The classic delay discounting task involved choices about money at delays of 1–90 days and only some of the outcomes were actually experienced by the participants. The novel real-time discounting task involved choices about an immediately consumable reward (playing a preferred game) at delays of 25–100 s, all of which were actually experienced by participants. Participants also provided subjective ratings of how much they liked playing the game and waiting to play. Girls with ADHD-C displayed greater delay discounting compared to boys with ADHD-C and TD girls and boys on the real-time discounting task. Diagnostic group differences were not evident on the classic discounting task. In addition, children with ADHD-C reported wanting to play the game more and liking waiting to play the game less than TD children. This novel demonstration of greater delay discounting among girls with ADHD-C on a discounting task in which the rewards are immediately consumable and the delays are experienced in real-time informs our understanding of sex differences and motivational processes in children with ADHD. PMID:26549118

  14. Human alpha rhythms during visual delayed choice reaction time tasks: a magnetoencephalography study.

    Science.gov (United States)

    Babiloni, Claudio; Babiloni, Fabio; Carducci, Filippo; Cincotti, Febo; Del Percio, Claudio; Della Penna, Stefania; Franciotti, Raffaella; Pignotti, Sandro; Pizzella, Vittorio; Rossini, Paolo Maria; Sabatini, Elisabetta; Torquati, Kathya; Romani, Gian Luca

    2005-03-01

    Magnetoencephalography (MEG) includes fast and comfortable recording procedures very suitable for the neurophysiological study of cognitive functions in aged people. In this exploratory MEG study in normal young adults, we tested whether very simple short-term memory (STM) demands induce visible changes in amplitude and latency of surface alpha rhythms. Two delayed response tasks were used. In the STM condition, a simple cue stimulus (one bit) was memorized along a brief delay period (3.5-5.5 s). In the control (no short-term memory; NSTM) condition, the cue stimulus remained available along the delay period. To make extremely simple the tasks, the explicit demand was visuospatial but the retention could be also based on phonological and somatomotor coding. Compared to the control condition, the amplitude of the alpha 1 (6-8 Hz) ERD decreased in the left hemisphere, whereas the amplitude of the alpha 2 (8-10 Hz) and alpha 3 (10-12 Hz) event-related desynchronization (ERD) increased in right and left parietal areas, respectively. Furthermore, the latency of the alpha ERD peak was slightly but significantly (P rhythms in normal young adults. Copyright 2004 Wiley-Liss, Inc.

  15. Comparison of Motor Inhibition in Variants of the Instructed-Delay Choice Reaction Time Task

    Science.gov (United States)

    Quoilin, Caroline; Lambert, Julien; Jacob, Benvenuto; Klein, Pierre-Alexandre; Duque, Julie

    2016-01-01

    Using instructed-delay choice reaction time (RT) paradigms, many previous studies have shown that the motor system is transiently inhibited during response preparation: motor-evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS) over the primary motor cortex are typically suppressed during the delay period. This effect has been observed in both selected and non-selected effectors, although MEP changes in selected effectors have been more inconsistent across task versions. Here, we compared changes in MEP amplitudes in three different variants of an instructed-delay choice RT task. All variants required participants to choose between left and right index finger movements but the responses were either provided “in the air” (Variant 1), on a regular keyboard (Variant 2), or on a response device designed to control from premature responses (Variant 3). The task variants also differed according to the visual layout (more concrete in Variant 3) and depending on whether participants received a feedback of their performance (absent in Variant 1). Behavior was globally comparable between the three variants of the task although the propensity to respond prematurely was highest in Variant 2 and lowest in Variant 3. MEPs elicited in a non-selected hand were similarly suppressed in the three variants of the task. However, significant differences emerged when considering MEPs elicited in the selected hand: these MEPs were suppressed in Variants 1 and 3 whereas they were often facilitated in Variant 2, especially in the right dominant hand. In conclusion, MEPs elicited in selected muscles seem to be more sensitive to small variations to the task design than those recorded in non-selected effectors, probably because they reflect a complex combination of inhibitory and facilitatory influences on the motor output system. Finally, the use of a standard keyboard seems to be particularly inappropriate because it encourages participants to respond promptly

  16. Hippocampal lesions impair performance on a conditional delayed matching and non-matching to position task in the rat.

    Science.gov (United States)

    Sloan, Hazel L; Döbrössy, Màtè; Dunnett, Stephen B

    2006-08-10

    The hippocampus is thought to be involved in a range of cognitive processes, from the ability to acquire new memories, to the ability to learn about spatial relationships. Humans and monkeys with damage to the hippocampus are typically impaired on delayed matching to sample tasks, of which the operant delayed matching to position task (DMTP) is a rat analogue. The reported effects of hippocampal damage on DMTP vary, ranging from delay-dependent deficits to no deficit whatsoever. The present study investigates a novel memory task; the conditional delayed matching/non-matching to position task (CDM/NMTP) in the Skinner box. CDM/NMTP uses the presence of specific stimulus cues to signify whether a particular trial is matching or non-matching in nature. Thus, it incorporates both the task contingencies within one session, and supplements the requirement for remembering the side of the lever in the sample phase with attending to the stimulus and remembering the conditional discrimination for the rule. Rats were trained preoperatively and the effects of bilateral excitotoxic lesions of the hippocampus were examined on postoperative retention of the task. Rats with lesions of the hippocampus incurred a significant impairment on the task that was manifest at all delays intervals. Despite a bias towards matching during training, trials of either type were performed with equivalent accuracy and neither rule was affected differentially by the lesion. This task may prove useful in determining the cognitive roles of a range of brain areas.

  17. Computerized Spatial-Delayed Recognition Span Task: a specific tool to assess visuospatial working memory

    Directory of Open Access Journals (Sweden)

    Corina eSatler

    2015-04-01

    Full Text Available A new tablet device version (IOS platform of the Spatial Delayed Recognition Span Task (SDRST was developed with the aim of investigating visuospatial Working Memory (WM abilities based on touchscreen technology. This new WM testing application will be available to download for free in Apple Store app (SDRST app. In order to verify the feasibility of this computer-based task, we conducted three experiments with different manipulations and groups of participants. We were interested in investigating if (1 the SDRST is sensitive enough to tap into cognitive differences brought by ageing and dementia; (2 different experimental manipulations work successfully; (3 cortical brain activations seen in other WM tasks are also demonstrated here; and (4 non-human primates are able to answer the task. Performance (scores and response time was better for young than older adults and higher for the latter when compared to Alzheimer’s disease patients. All groups performed better with facial stimuli than with images of scenes and with emotional than with neutral stimuli. Electrophysiology data showed activation on prefrontal and frontal areas of scalp, theta band activity on the midline area, and gamma activity in left temporal area. There are all scalp regions known to be related to attention and WM. Besides those data, our sample of adult captive capuchin monkeys (Sapajus libidinosus answered the task above chance level. Taken together, these results corroborate the reliability of this new computer-based SDRST as a measure of visuospatial WM in clinical and non-clinical populations as well as in non-human primates. Its tablet app allows the task to be administered in a wide range of settings, including hospitals, homes, schools, laboratories, universities, and research institutions.

  18. Review of Recent Research Using Constant Time Delay to Teach Chained Tasks to Persons with Developmental Disabilities

    Science.gov (United States)

    Dogoe, Maud; Banda, Devender R.

    2009-01-01

    We reviewed twelve studies that used the constant time delay (CTD) procedure to teach chained tasks to individuals with developmental disabilities from years 1996-2006. Variables analyzed include types of tasks that have been taught with the procedure, how effective CTD has been in teaching participants, and whether researchers have investigated…

  19. Symbolic Models for Nonlinear Time-Varying Time-Delay Systems via Alternating Approximate Bisimulation

    CERN Document Server

    Pola, Giordano; Di Benedetto, Maria Domenica

    2010-01-01

    Time-delay systems are an important class of dynamical systems that provide a solid mathematical framework to deal with many application domains of interest. In this paper we focus on nonlinear control systems with unknown and time-varying delay signals and we propose one approach to the control design of such systems, which is based on the construction of symbolic models. Symbolic models are abstract descriptions of dynamical systems in which one symbolic state and one symbolic input correspond to an aggregate of states and an aggregate of inputs. We first introduce the notion of incremental input-delay-to-state stability and characterize it by means of Liapunov-Krasovskii functionals. We then derive sufficient conditions for the existence of symbolic models that are shown to be alternating approximately bisimilar to the original system. Further results are also derived which prove the computability of the proposed symbolic models in a finite number of steps.

  20. Simulator study of the effect of visual-motion time delays on pilot tracking performance with an audio side task

    Science.gov (United States)

    Riley, D. R.; Miller, G. K., Jr.

    1978-01-01

    The effect of time delay was determined in the visual and motion cues in a flight simulator on pilot performance in tracking a target aircraft that was oscillating sinusoidally in altitude only. An audio side task was used to assure the subject was fully occupied at all times. The results indicate that, within the test grid employed, about the same acceptable time delay (250 msec) was obtained for a single aircraft (fighter type) by each of two subjects for both fixed-base and motion-base conditions. Acceptable time delay is defined as the largest amount of delay that can be inserted simultaneously into the visual and motion cues before performance degradation occurs. A statistical analysis of the data was made to establish this value of time delay. Audio side task provided quantitative data that documented the subject's work level.

  1. The nature of impulsivity: visual exposure to natural environments decreases impulsive decision-making in a delay discounting task.

    Science.gov (United States)

    Berry, Meredith S; Sweeney, Mary M; Morath, Justice; Odum, Amy L; Jordan, Kerry E

    2014-01-01

    The benefits of visual exposure to natural environments for human well-being in areas of stress reduction, mood improvement, and attention restoration are well documented, but the effects of natural environments on impulsive decision-making remain unknown. Impulsive decision-making in delay discounting offers generality, predictive validity, and insight into decision-making related to unhealthy behaviors. The present experiment evaluated differences in such decision-making in humans experiencing visual exposure to one of the following conditions: natural (e.g., mountains), built (e.g., buildings), or control (e.g., triangles) using a delay discounting task that required participants to choose between immediate and delayed hypothetical monetary outcomes. Participants viewed the images before and during the delay discounting task. Participants were less impulsive in the condition providing visual exposure to natural scenes compared to built and geometric scenes. Results suggest that exposure to natural environments results in decreased impulsive decision-making relative to built environments.

  2. Spatial memory: behavioral determinants of persistence in the watermaze delayed matching-to-place task.

    Science.gov (United States)

    da Silva, Bruno M; Bast, Tobias; Morris, Richard G M

    2013-12-17

    The watermaze delayed matching-to-place (DMP) task was modified to include probe trials, to quantify search preference for the correct place. Using a zone analysis of search preference, a gradual decay of one-trial memory in rats was observed over 24 h with weak memory consistently detected at a retention interval of 6 h, but unreliably at 24 h. This forgetting function in the watermaze was similar to that found using a search-preference measure in a food-reinforced dry-land DMP task in a previous study. In a search for strong and weak encoding conditions, essential for a later behavioral tagging study, three encoding trials gave strong 6-h and 24-h memory when trials were separated by 10 min (spaced training) but not 15 sec (massed training). The use of six encoding trials gave good 6-h memory with both spaced and massed training. With respect to weak encoding, placement on the escape platform, instead of the rat swimming to it, resulted in detectable memory at 30 min but this had faded to chance within 24 h. In contrast to the search-preference measure, latencies to cross the correct place revealed neither the gradual forgetting of place memory nor the benefit of spaced training.

  3. Self-Administered Cocaine Causes Long-Lasting Increases in Impulsive Choice in a Delay Discounting Task

    OpenAIRE

    Mendez, Ian A.; Nicholas W Simon; Hart, Nigel; Mitchell, Marci R.; Nation, Jack R.; Wellman, Paul J.; Setlow, Barry

    2010-01-01

    Cocaine use is associated with high levels of impulsive choice (preference for immediate over delayed rewards), but it is not clear whether cocaine use causes elevated impulsive choice, or whether elevated impulsive choice is solely a predisposing factor for cocaine use. This study examined the effects of prior cocaine self-administration on rats performing a delay discounting task commonly used to measure impulsive choice. Male Long-Evans rats were implanted with intravenous catheters, and f...

  4. Electrocorticographic language mapping with a listening task consisting of alternating speech and music phrases.

    Science.gov (United States)

    Mooij, Anne H; Huiskamp, Geertjan J M; Gosselaar, Peter H; Ferrier, Cyrille H

    2016-02-01

    Electrocorticographic (ECoG) mapping of high gamma activity induced by language tasks has been proposed as a more patient friendly alternative for electrocortical stimulation mapping (ESM), the gold standard in pre-surgical language mapping of epilepsy patients. However, ECoG mapping often reveals more language areas than considered critical with ESM. We investigated if critical language areas can be identified with a listening task consisting of speech and music phrases. Nine patients with implanted subdural grid electrodes listened to an audio fragment in which music and speech alternated. We analysed ECoG power in the 65-95 Hz band and obtained task-related activity patterns in electrodes over language areas. We compared the spatial distribution of sites that discriminated between listening to speech and music to ESM results using sensitivity and specificity calculations. Our listening task of alternating speech and music phrases had a low sensitivity (0.32) but a high specificity (0.95). The high specificity indicates that this test does indeed point to areas that are critical to language processing. Our test cannot replace ESM, but this short and simple task can give a reliable indication where to find critical language areas, better than ECoG mapping using language tasks alone. Copyright © 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  5. Environmentally Benign Energetic Time Delay Compositions: Alternatives for the U.S. Army Hand-Held Signal

    Science.gov (United States)

    2014-07-13

    2014, pp 305-314 305 Environmentally Benign Energetic Time Delay Compositions: Alternatives for the U.S. Army Hand- Held Signal Jay C. Poret...munitions such as hand grenades and signaling devices. For example, U.S. Army hand- held signals (HHS) use a pyrotechnic delay element to properly time...compositions for use in the U.S. Army hand- held signal. The large thermal mass of the HHS delay housing, combined with the long burning time requirement

  6. 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

  7. Electrocorticographic language mapping with a listening task consisting of alternating speech and music phrases

    NARCIS (Netherlands)

    Mooij, Anne H.; Huiskamp, Geertjan J M; Gosselaar, Peter H.; Ferrier, Cyrille H.

    2016-01-01

    OBJECTIVE: Electrocorticographic (ECoG) mapping of high gamma activity induced by language tasks has been proposed as a more patient friendly alternative for electrocortical stimulation mapping (ESM), the gold standard in pre-surgical language mapping of epilepsy patients. However, ECoG mapping

  8. 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 sk

  9. Pigeon's (Columba livia) paradoxical preference for the suboptimal alternative in a complex foraging task.

    Science.gov (United States)

    Zentall, Thomas R; Case, Jacob P; Luong, Jasmine

    2016-05-01

    Recent research has examined a task in which choice of 1 alternative A provides reinforcement and in addition, allows access to alternative B that also provides reinforcement. However, although initial choice of B also provides reinforcement, it does not also allow access to A. Thus, optimal performance would be to always choose A. Curiously, Salwiczek et al. (2012) reported that adult wrasse (cleaner) fish mastered this task within 50 trials, whereas monkeys and apes had great difficulty with it. The authors attributed the species differences to ecological differences in the species foraging experiences. However, Pepperberg and Hartsfield (2014) found that parrots too learned this task. In Experiment 1, using the manual presentation of stimuli, we found that pigeons actually showed a reliable preference for B, the suboptimal alternative. In Experiment 2, we replicated the suboptimal preference using an automated version of the task. We hypothesized that the pigeons may have been basing their preference on the frequency of reinforcement associated with each alternative (initially, all trials ended with choice of B, whereas only half of the trials involved choice of A). In Experiment 3, we tested the hypothesis that the pigeons' preference was influenced by the frequency of reinforcements associated with A and B. Thus, when the pigeon chose A, we replaced B with C, so reinforcement occurred to B only when they chose it first. With this procedure we found that B was no longer preferred over A. Thus, the data supported our hypothesis. (PsycINFO Database Record

  10. Human cortical rhythms during visual delayed choice reaction time tasks. A high-resolution EEG study on normal aging.

    Science.gov (United States)

    Babiloni, Claudio; Babiloni, Fabio; Carducci, Filippo; Cappa, Stefano F; Cincotti, Febo; Del Percio, Claudio; Miniussi, Carlo; Vito Moretti, Davide; Rossi, Simone; Sosta, Katiuscia; Rossini, Paolo Maria

    2004-08-12

    Neuroimaging cognitive study of aging requires simple tasks ensuring a high rate of correct performances even in stressful neurophysiological settings. Here two simple delayed choice reaction time tasks were used to unveil event-related desynchronization (ERD) of theta (4-6 Hz) and alpha (6-12 Hz) electroencephalographic rhythms across normal aging. In the first condition, a cue stimulus (one bit) was memorized along a brief delay period (3.5-5.5 s). The explicit demand was visuo-spatial, but the retention could be also based on phonological and somatomotor coding. In the second condition, the cue stimulus remained available along the delay period. Correct performances were higher than 95% in both groups and tasks, although they were significantly better in young than elderly subjects (P < 0.03). During the delay period, theta and alpha ERD accompanying correct responses were recognized in the two groups, the alpha ERD being stronger and prolonged during the memory than non-memory task. On the other hand, the fronto-parietal theta and parietal alpha ERD were stronger in young than elderly subjects during both tasks. Notably, the frontal alpha ERD was negligible in elderly subjects. In conclusion, the present simple tasks unveiled in elderly compared to young subjects (i) a weaker involvement of (para)hippocampal-cortical circuits as revealed by theta ERD and (ii) a weaker involvement of "executive" thalamo-cortical circuits as revealed by frontal alpha ERD. These effects might worsen behavioral performances to the simple cognitive tasks with age. The present protocol is promising for the neuroimaging study of pathological aging.

  11. Delayed response task performance as a function of age in cynomolgus monkeys (Macaca fascicularis)

    DEFF Research Database (Denmark)

    Darusman, H S; Call, J; Sajuthi, D

    2014-01-01

    We compared delayed response task performance in young, middle-aged, and old cynomolgus monkeys using three memory tests that have been used with non-human primates. Eighteen cynomolgus monkeys-6 young (4-9 years), 6 middle-aged (10-19 years), and 6 old (above 20 years)-were tested. In general...

  12. Gaze alternation in dogs and toddlers in an unsolvable task: evidence of an audience effect.

    Science.gov (United States)

    Marshall-Pescini, S; Colombo, E; Passalacqua, C; Merola, I; Prato-Previde, E

    2013-11-01

    Dogs have been shown to use human-directed gazing behaviour and gaze alternation in numerous contexts; however, it is still unclear whether this behaviour can be considered an intentional and referential communicative act. In the current study, adult dogs and preverbal toddlers were tested using the classic unsolvable task paradigm, but varying the attentional stance of the participating audience (the experimenter and the caregiver). The aims were to assess (1) whether dogs and toddlers would use gaze alternation behaviour in similar manners when the task became unsolvable, and (2) whether both dogs and toddlers would take into account the attentional stance of the audience when initiating a communicative interaction. Results indicated that both toddlers and dogs increased their gaze alternation behaviour between the apparatus and caregiver when the task became unsolvable, and toddlers also showed an increase in pointing behaviour. Furthermore, both species showed a capacity to take into account the attentional stance of the audience when manifesting gaze alternation behaviours towards them. Taken together, these results suggest that gaze alternation is both an intentional and referential communicative act and that both species can take into account the need for audience attention when communicating with them.

  13. Modeling the insect mushroom bodies: application to a delayed match-to-sample task.

    Science.gov (United States)

    Arena, Paolo; Patané, Luca; Stornanti, Vincenzo; Termini, Pietro Savio; Zäpf, Bianca; Strauss, Roland

    2013-05-01

    Despite their small brains, insects show advanced capabilities in learning and task solving. Flies, honeybees and ants are becoming a reference point in neuroscience and a main source of inspiration for autonomous robot design issues and control algorithms. In particular, honeybees demonstrate to be able to autonomously abstract complex associations and apply them in tasks involving different sensory modalities within the insect brain. Mushroom Bodies (MBs) are worthy of primary attention for understanding memory and learning functions in insects. In fact, even if their main role regards olfactory conditioning, they are involved in many behavioral achievements and learning capabilities, as has been shown in honeybees and flies. Owing to the many neurogenetic tools, the fruit fly Drosophila became a source of information for the neuroarchitecture and biochemistry of the MBs, although the MBs of flies are by far simpler in organization than their honeybee orthologs. Electrophysiological studies, in turn, became available on the MBs of locusts and honeybees. In this paper a novel bio-inspired neural architecture is presented, which represents a generalized insect MB with the basic features taken from fruit fly neuroanatomy. By mimicking a number of different MB functions and architecture, we can replace and improve formerly used artificial neural networks. The model is a multi-layer spiking neural network where key elements of the insect brain, the antennal lobes, the lateral horn region, the MBs, and their mutual interactions are modeled. In particular, the model is based on the role of parts of the MBs named MB-lobes, where interesting processing mechanisms arise on the basis of spatio-temporal pattern formation. The introduced network is able to model learning mechanisms like olfactory conditioning seen in honeybees and flies and was found able also to perform more complex and abstract associations, like the delayed matching-to-sample tasks known only from

  14. The amblyopic eye in subjects with anisometropia show increased saccadic latency in the delayed saccade task

    Directory of Open Access Journals (Sweden)

    Maciej ePerdziak

    2014-10-01

    Full Text Available The term amblyopia is used to describe reduced visual function in one eye (or both eyes, though not so often which cannot be fully improved by refractive correction and explained by the organic cause observed during regular eye examination. This developmental disorder of spatial vision affects about 2-5% of the population and is associated with abnormal visual experience (e.g. anisometropia, strabismus during infancy or early childhood. Several studies have shown prolongation of saccadic latency time in amblyopic eye. In our opinion, study of saccadic latency in the context of central vision deficits assessment, should be based on central retina stimulation. For this reason, we proposed saccade delayed task. It requires inhibitory processing for maintaining fixation on the central target until it disappears – what constitutes the GO signal for saccade. The experiment consisted of 100 trials for each eye and was performed under two viewing conditions: monocular amblyopic / non-dominant eye and monocular dominant eye. We examined saccadic latency in 16 subjects (mean age 30±11 years with anisometropic amblyopia (two subjects had also microtropia and in 17 control subjects (mean age 28±8 years. Participants were instructed to look at central (fixation target and when it disappears, to make the saccade toward the periphery (10 deg as fast as possible, either left or the right target. The study results have proved the significant difference in saccadic latency between the amblyopic (mean 262±48 ms and dominant (mean 237±45 ms eye, in anisometropic group. In the control group, the saccadic latency for dominant (mean 226±32ms and non-dominant (mean 230±29 ms eye was not significantly different.By the use of LATER (Linear Approach to the Threshold with Ergodic Rate decision model we interpret our findings as a decrease in accumulation of visual information acquired by means of central (affected retina in subjects with anisometropic amblyopia.

  15. A novel delayed non-match to sample object recognition task that allows simultaneous in vivo microdialysis.

    Science.gov (United States)

    Ihalainen, Jouni; Sarajärvi, Timo; Kemppainen, Susanna; Keski-Rahkonen, Pekka; Lehtonen, Marko; Tanila, Heikki

    2010-06-15

    We present a modification of the widely used delayed non-match to sample (DNMS) paradigm for assessment of object recognition memory that can be combined with simultaneous in vivo microdialysis. The present study provides evidence that hippocampal ACh release increases from baseline during active exploration of the test environment and an empty test board, but a specific further increase is seen during the recognition memory task performance. This novel experimental model offers a good tool to study the impact of selective lesions or pharmacological manipulation simultaneously on neurotransmitter levels and memory task performance.

  16. Impaired executive control and reward circuit in Internet gaming addicts under a delay discounting task: independent component analysis.

    Science.gov (United States)

    Wang, Yifan; Wu, Lingdan; Zhou, Hongli; Lin, Xiao; Zhang, Yifen; Du, Xiaoxia; Dong, Guangheng

    2017-04-01

    This study utilized independent component analysis to explore the abnormal functional connectivity (FC) in male participants with Internet gaming disorder (IGD). Functional magnetic resonance imaging and behavioral data were collected from 21 healthy controls (HC) and 18 IGD patients when they were performing a delay discounting task. Behavioral results revealed that the IGD patients showed higher delay discounting rates than HC. Two networks were found to be associated with IGD: (1) the executive control network containing the anterior cingulate cortex and the medial and superior frontal gyrus, and (2) the basal ganglia network containing the lentiform nucleus. Comparing to HC, IGD exhibited stronger FC when selecting small and now options. In addition, the delay discounting rates were positively correlated with the modulation of the two networks and the reaction time. The results suggested that the IGD patients have enhanced sensitivity to reward and decreased ability to control their impulsivity effectively, which leads to myopic decision making.

  17. Semantic Interference in Immediate and Delayed Naming and Reading: Attention and Task Decisions

    Science.gov (United States)

    Piai, Vitoria; Roelofs, Ardi; Schriefers, Herbert

    2011-01-01

    Disagreement exists about whether lexical selection in word production is a competitive process. Competition predicts semantic interference from distractor words in immediate but not in delayed picture naming. In contrast, Janssen, Schirm, Mahon, and Caramazza (2008) obtained semantic interference in delayed picture naming when participants had to…

  18. The nature of impulsivity: visual exposure to natural environments decreases impulsive decision-making in a delay discounting task.

    Directory of Open Access Journals (Sweden)

    Meredith S Berry

    Full Text Available The benefits of visual exposure to natural environments for human well-being in areas of stress reduction, mood improvement, and attention restoration are well documented, but the effects of natural environments on impulsive decision-making remain unknown. Impulsive decision-making in delay discounting offers generality, predictive validity, and insight into decision-making related to unhealthy behaviors. The present experiment evaluated differences in such decision-making in humans experiencing visual exposure to one of the following conditions: natural (e.g., mountains, built (e.g., buildings, or control (e.g., triangles using a delay discounting task that required participants to choose between immediate and delayed hypothetical monetary outcomes. Participants viewed the images before and during the delay discounting task. Participants were less impulsive in the condition providing visual exposure to natural scenes compared to built and geometric scenes. Results suggest that exposure to natural environments results in decreased impulsive decision-making relative to built environments.

  19. Medial Prefrontal Cortex and Dorsomedial Striatum Are Necessary for the Trial-Unique, Delayed Nonmatching-to-Location (TUNL) Task in Rats: Role of NMDA Receptors

    Science.gov (United States)

    Davies, Don A.; Hurtubise, Jessica L.; Greba, Quentin; Howland, John G.

    2017-01-01

    The trial-unique, delayed nonmatching-to-location (TUNL) task is a recently developed behavioral task that measures spatial working memory and a form of pattern separation in touchscreen-equipped operant conditioning chambers. Limited information exists regarding the neurotransmitters and neural substrates involved in the task. The present…

  20. Semantic interference in immediate and delayed naming and reading: Attention and task decisions

    NARCIS (Netherlands)

    Piai, V.; Roelofs, A.P.A.; Schriefers, H.J.

    2011-01-01

    Disagreement exists about whether lexical selection in word production is a competitive process. Competition predicts semantic interference from distractor words in immediate but not in delayed picture naming. In contrast, Janssen, Schirm, Mahon, and Caramazza (2008) obtained semantic interference

  1. Semantic interference in immediate and delayed naming and reading: Attention and task decisions

    NARCIS (Netherlands)

    Piai, V.; Roelofs, A.P.A.; Schriefers, H.J.

    2011-01-01

    Disagreement exists about whether lexical selection in word production is a competitive process. Competition predicts semantic interference from distractor words in immediate but not in delayed picture naming. In contrast, Janssen, Schirm, Mahon, and Caramazza (2008) obtained semantic interference i

  2. Bias at the racetrack: effects of individual expertise and task importance on predecision reevaluation of alternatives.

    Science.gov (United States)

    Brownstein, Aaron L; Read, Stephen J; Simon, Dan

    2004-07-01

    These studies were designed to test cognitive dissonance theory's assertion that alternatives are not reevaluated before a choice. Participants viewed information about horses in a simulated race and rated each one's chance of winning three times before placing their bet and once after placing it. It was found that ratings of the chosen horse increased within the predecision period as well as after betting. Predecision bolstering occurred even when participants did not expect to bet, and predecision preference increased with task importance and participant expertise. The findings are attributed to maintenance of consistency throughout a cognitive system.

  3. How target-lure similarity shapes confidence judgments in multiple-alternative decision tasks.

    Science.gov (United States)

    Horry, Ruth; Brewer, Neil

    2016-12-01

    Confidence judgments in 2-alternative decisions have been the subject of a great deal of research in cognitive psychology. Sequential sampling models have been particularly successful at explaining confidence judgments in such decisions and the relationships between confidence, accuracy, and response latencies. Across 5 experiments, we derived predictions from sequential sampling models and applied them to more complex decisions: multiple-alternative decisions, and compound decisions, such as eyewitness identification tasks, in which a target may be present or absent within the array of items that can be selected. We hypothesized that, when a decision-maker chooses an item, confidence in that decision reflects the relative evidence for the chosen item over all unchosen items. We tested this hypothesis by manipulating the similarity between the target (or target-replacement, for trials in which the target was not present in the array) and the weakest lure(s). As target-lure similarity decreased, confidence in correct target identifications increased, while response latencies decreased. When the decision-maker chose none of the items, the similarity between the target-replacement and the lures was unrelated to confidence. We conclude that similar mechanisms underpin confidence judgments in multiple-alternative and positive compound decisions as in simpler, 2-alternative decisions. A goal of future research should be to formally extend sequential sampling models to more complex decisions, such that it will be possible to establish whether diffusion or accumulator models provide a better fit to the data. (PsycINFO Database Record

  4. Delaying reinforcement in an autoshaping task generates adjunctive and superstitious behaviors.

    Science.gov (United States)

    Messing, R B; Kleven, M S; Sparber, S B

    1986-12-01

    Rats were autoshaped to touch a lever upon its insertion into an operant chamber on a 45 s random time schedule. Occurrence of a reinforced touch on each of 12 lever insertions per session and nose-pokes at the retracted lever were monitored, as was exploratory rearing activity. Delays of 2, 4 or 8 s interposed between the retraction of the lever, which occurred either after 15 s or after a touch response, and delivery of the food pellet reward, resulted in progressively slower acquisition of the extended lever touch response. However, if rats had already acquired the response under immediate reinforcement conditions, the delays subsequently introduced did not cause a decline in autoshaped touch responding. Nose-pokes at the retracted lever occurred during both intertrial and reinforcement delay intervals over the course of autoshaping. The appearance and frequency of these (adjunctive or superstitious) behaviors depended upon the reinforcement delay and behavioral history. These interval behaviors offer measurements of learning not based on arbitrary criteria; they thus provide information about effects on endpoints, or a more global approach to learning. Copyright © 1986. Published by Elsevier B.V.

  5. What can the monetary incentive delay task tell us about the neural processing of reward and punishment?

    Directory of Open Access Journals (Sweden)

    Lutz K

    2014-04-01

    Full Text Available Kai Lutz,1–3 Mario Widmer1,2,41Department of Neurology, University Hospital Zürich, Zürich, 2Cereneo, Center for Neurology and Rehabilitation, Vitznau, 3Division of Neuropsychology, Institute of Psychology, University of Zürich, Zürich, 4Neural Control of Movement Lab, ETH Zürich, Zürich, SwitzerlandAbstract: Since its introduction in 2000, the monetary incentive delay (MID task has been used extensively to investigate changes in neural activity in response to the processing of reward and punishment in healthy, but also in clinical populations. Typically, the MID task requires an individual to react to a target stimulus presented after an incentive cue to win or to avoid losing the indicated reward. In doing so, this paradigm allows the detailed examination of different stages of reward processing like reward prediction, anticipation, outcome processing, and consumption as well as the processing of tasks under different reward conditions. This review gives an overview of different utilizations of the MID task by outlining the neuronal processes involved in distinct aspects of human reward processing, such as anticipation versus consumption, reward versus punishment, and, with a special focus, reward-based learning processes. Furthermore, literature on specific influences on reward processing like behavioral, clinical and developmental influences, is reviewed, describing current findings and possible future directions.Keywords: reward, punishment, dopamine, reward system

  6. Working Memory Impairment in People with Williams Syndrome: Effects of Delay, Task and Stimuli

    OpenAIRE

    O'Hearn, Kirsten; Courtney, Susan; Street, Whitney; Landau, Barbara

    2008-01-01

    Williams syndrome (WS) is a neurodevelopmental disorder associated with impaired visuospatial representations subserved by the dorsal stream and relatively strong object recognition abilities subserved by the ventral stream. There is conflicting evidence on whether this uneven pattern extends to working memory (WM) in WS. The present studies provide a new perspective, testing WM for a single stimulus using a delayed recognition paradigm in individuals with WS and typically developing children...

  7. The effect of opponent type on human performance in a three-alternative choice task.

    Science.gov (United States)

    Lie, Celia; Baxter, Jennifer; Alsop, Brent

    2013-10-01

    Adult participants played computerised games of "Paper Scissors Rock". Participants in one group were told that they were playing against the computer, and those in the other group were told that they were playing against another participant in the adjacent room. The participant who won the most games would receive a $50 prize. For both groups however, the opponent's responses (paper, scissors, or rock) were generated by the computer, and the distribution of these responses was varied across four blocks of 126 trials. Results were analysed using the generalised matching law for the three possible pairs of alternatives (paper vs. scissors, paper vs. rock, and scissors vs. rock) across all participants in each group. Overall, significantly higher estimates of sensitivity to the distribution of opponent's responses were obtained from participants who were told their opponent was a computer compared to participants who were told their opponent was another participant. While adding to the existing literature showing that the generalised matching law is an adequate descriptor of human three-alternative choice behaviour, these findings show that external factors such as perceived opponent type can affect the efficacy of reinforcer contingencies on human behaviour. This suggests that generalising the results from tasks performed against a computer to real-life human-to-human interactions warrants some caution.

  8. Task-irrelevant distractors in the delay period interfere selectively with visual short-term memory for spatial locations.

    Science.gov (United States)

    Marini, Francesco; Scott, Jerry; Aron, Adam R; Ester, Edward F

    2017-07-01

    Visual short-term memory (VSTM) enables the representation of information in a readily accessible state. VSTM is typically conceptualized as a form of "active" storage that is resistant to interference or disruption, yet several recent studies have shown that under some circumstances task-irrelevant distractors may indeed disrupt performance. Here, we investigated how task-irrelevant visual distractors affected VSTM by asking whether distractors induce a general loss of remembered information or selectively interfere with memory representations. In a VSTM task, participants recalled the spatial location of a target visual stimulus after a delay in which distractors were presented on 75% of trials. Notably, the distractor's eccentricity always matched the eccentricity of the target, while in the critical conditions the distractor's angular position was shifted either clockwise or counterclockwise relative to the target. We then computed estimates of recall error for both eccentricity and polar angle. A general interference model would predict an effect of distractors on both polar angle and eccentricity errors, while a selective interference model would predict effects of distractors on angle but not on eccentricity errors. Results showed that for stimulus angle there was an increase in the magnitude and variability of recall errors. However, distractors had no effect on estimates of stimulus eccentricity. Our results suggest that distractors selectively interfere with VSTM for spatial locations.

  9. Neural dissociation of food- and money-related reward processing using an abstract incentive delay task.

    Science.gov (United States)

    Simon, Joe J; Skunde, Mandy; Wu, Mudan; Schnell, Knut; Herpertz, Sabine C; Bendszus, Martin; Herzog, Wolfgang; Friederich, Hans-Christoph

    2015-08-01

    Food is an innate reward stimulus related to energy homeostasis and survival, whereas money is considered a more general reward stimulus that gains a rewarding value through learning experiences. Although the underlying neural processing for both modalities of reward has been investigated independently from one another, a more detailed investigation of neural similarities and/or differences between food and monetary reward is still missing. Here, we investigated the neural processing of food compared with monetary-related rewards in 27 healthy, normal-weight women using functional magnetic resonance imaging. We developed a task distinguishing between the anticipation and the receipt of either abstract food or monetary reward. Both tasks activated the ventral striatum during the expectation of a reward. Compared with money, greater food-related activations were observed in prefrontal, parietal and central midline structures during the anticipation and lateral orbitofrontal cortex (lOFC) during the receipt of food reward. Furthermore, during the receipt of food reward, brain activation in the secondary taste cortex was positively related to the body mass index. These results indicate that food-dependent activations encompass to a greater extent brain regions involved in self-control and self-reflection during the anticipation and phylogenetically older parts of the lOFC during the receipt of reward.

  10. Development and Alternate Form Reliability of the Complex Task Performance Assessment (CTPA) for People With Mild Stroke.

    Science.gov (United States)

    Saa, Juan Pablo; Doherty, Meghan; Young, Alexis; Spiers, Meredith; Leary, Emily; Wolf, Timothy J

    Cognitive impairment is a common consequence of mild stroke. Current performance-based assessments for mild stroke can detect mild impairments in executive function but lack alternate forms to be used as outcome measures. This study aimed to develop an alternate form of the Complex Task Performance Assessment (CTPA-Alt), a performance-based assessment of executive function, and to establish the alternate form reliability of the CTPA-Alt. A repeated-measures study was conducted with 26 community participants. Participants were screened for eligibility and administered both forms of the CTPA; administration order was alternated. Overall performance was significantly correlated (rs = .44, p = .03), but pattern of scoring differed by CTPA form and order of administration. Our results indicate that the CTPA forms were similar but that the specific tasks in each form were different. The CTPA may be used as an ecologically valid outcome assessment with further considerations. Copyright © 2017 by the American Occupational Therapy Association, Inc.

  11. Providing Alternative Reinforcers to Facilitate Tolerance to Delayed Reinforcement Following Functional Communication Training

    Science.gov (United States)

    Austin, Jillian E.; Tiger, Jeffrey H.

    2015-01-01

    The earliest stages of functional communication training (FCT) involve providing immediate and continuous reinforcement for a communicative response (FCR) that is functionally equivalent to the targeted problem behavior. However, maintaining immediate reinforcement is not practical, and the introduction of delays is associated with increased…

  12. The intertemporal choice behaviour: Classical and alternative delay discounting models and control techniques

    Directory of Open Access Journals (Sweden)

    Aldo G. S. Ventre

    2012-11-01

    Full Text Available Hyperbolic discounting refers to the tendency for people to increasingly choose a smaller-sooner reward over a larger-later reward as the delay occurs sooner rather than later in time. When offered a larger reward in exchange for waiting a set amount of time, people act less impulsively (i.e., choose to wait as the rewards happen further in the future. Put another way, people avoid waiting more as the wait nears the present time.

  13. Enabling Dynamic Process Simulators to Perform Alternative Tasks: A Time-stepper Based Toolkit for Computer-Aided Analysis

    OpenAIRE

    Siettos, C. I.; Pantelides, C. C.; Kevrekidis, I.G.

    2003-01-01

    We discuss computational superstructures that, using repeated, appropriately initialized short calls, enable temporal process simulators to perform alternative tasks such as fixed point computation, stability analysis and projective integration. We illustrate these concepts through the acceleration of a gPROMS-based Rapid Pressure Swing Adsorption simulation, and discuss their scope and possible extensions.

  14. Alternatives to switch-cost scoring in the task-switching paradigm: their reliability and increased validity.

    Science.gov (United States)

    Hughes, Meredith M; Linck, Jared A; Bowles, Anita R; Koeth, Joel T; Bunting, Michael F

    2014-09-01

    In the task-switching paradigm, the latency switch-cost score-the difference in mean reaction time between switch and nonswitch trials-is the traditional measure of task-switching ability. However, this score does not reflect accuracy, where switch costs may also emerge. In two experiments that varied in response deadlines (unlimited vs. limited time), we evaluated the measurement properties of two traditional switch-cost scoring methods (the latency switch-cost score and the accuracy switch-cost score) and three alternatives (a rate residual score, a bin score, and an inverse efficiency score). Scores from the rate residual, bin score, and inverse efficiency methods had comparable reliability for latency switch-cost scores without response deadlines but were more reliable than latency switch-cost scores when higher error rates were induced with a response deadline. All three alternative scoring methods appropriately accounted for differences in accuracy switch costs when higher error rates were induced, whereas pure latency switch-cost scores did not. Critically, only the rate residual and bin score methods were more valid indicators of task-switching ability; they demonstrated stronger relationships with performance on an independent measure of executive functioning (the antisaccade analogue task), and they allowed the detection of larger effect sizes when examining within-task congruency effects. All of the three alternative scoring methods provide researchers with a better measure of task-switching ability than do traditional scoring methods, because they each simultaneously account for latency and accuracy costs. Overall, the three alternative scoring methods were all superior to the traditional latency switch-cost scoring method, but the strongest methods were the rate residual and bin score methods.

  15. On bifurcation delay: An alternative approach using Geometric Singular Perturbation Theory

    Science.gov (United States)

    Hsu, Ting-Hao

    2017-02-01

    To explain the phenomenon of bifurcation delay, which occurs in planar systems of the form x ˙ = ɛf (x , z , ɛ), z ˙ = g (x , z , ɛ) z, where f (x , 0 , 0) > 0 and g (x , 0 , 0) changes sign at least once on the x-axis, we use the Exchange Lemma in Geometric Singular Perturbation Theory to track the limiting behavior of the solutions. Using the trick of extending dimension to overcome the degeneracy at the turning point, we show that the limiting attracting and repulsion points are given by the well-known entry-exit function, and the minimum of z on the trajectory is of order exp ⁡ (- 1 / ɛ). Also we prove smoothness of the return map up to arbitrary finite order in ɛ.

  16. Delayed incubation as an alternative method to sample storage for enumeration of E. coli and culturable bacteria in water.

    Science.gov (United States)

    Guardabassi, L; Gravesen, J; Lund, C; Bagge, L; Dalsgaard, A

    2002-11-01

    The effects of sample storage on enumeration of Escherichia coli in marine bathing water and culturable bacteria in drinking water were evaluated. Results showed that overnight storage at 0-5 degrees C significantly reduced the counts of E. coli in bathing water (p = 0.0001) with a mean reduction of 25%. A similar effect of sample storage was observed for the enumeration of culturable bacteria in drinking water at 22 +/- 2 degrees C for 66 +/- 4 h (p = 0.0074; mean reduction = 25%) or at 36 +/- 2 degrees C for 44 +/- 4h (p = 0.0353; mean reduction = 6%). The use of a delayed incubation method, i.e. overnight storage at 0-5 degrees C of inoculated agar plates prior to incubation, did not significantly affect the counts of culturable bacteria when plates were incubated at 22 + 2 degrees C for 66 +/- 4 h, whereas it resulted in a significant increase of the bacterial numbers when plates were incubated at 36 +/- 2 degrees C for 44 +/- 4 h (p = 0.0002; mean increase = 32%). Based on these results, it is suggested to avoid the use of overnight or longer sample storage for the enumeration of E. coli in bathing water samples, as well as for the enumeration of culturable bacteria in drinking water. The delayed incubation method appears to be a reliable procedure for the enumeration of culturable bacteria and could represent a valid alternative to sample storage in order to overcome problems associated with the performance of bacteriological counts during weekends or statutory holidays. However, a multi-laboratory study is needed to evaluate the reproducibility of the delayed incubation method for the enumeration of culturable bacteria and its possible use for the enumeration of E. coli by membrane filtration.

  17. Delay aversion but preference for large and rare rewards in two choice tasks: implications for the measurement of self-control parameters

    Directory of Open Access Journals (Sweden)

    Laviola Giovanni

    2006-06-01

    Full Text Available Abstract Background Impulsivity is defined as intolerance/aversion to waiting for reward. In intolerance-to-delay (ID protocols, animals must choose between small/soon (SS versus large/late (LL rewards. In the probabilistic discount (PD protocols, animals are faced with choice between small/sure (SS versus large/luck-linked (LLL rewards. It has been suggested that PD protocols also measure impulsivity, however, a clear dissociation has been reported between delay and probability discounting. Results Wistar adolescent rats (30- to 46-day-old were tested using either protocol in drug-free state. In the ID protocol, animals showed a marked shift from LL to SS reward when delay increased, and this despite adverse consequences on the total amount of food obtained. In the PD protocol, animals developed a stable preference for LLL reward, and maintained it even when SS and LLL options were predicted and demonstrated to become indifferent. We demonstrate a clear dissociation between these two protocols. In the ID task, the aversion to delay was anti-economical and reflected impulsivity. In the PD task, preference for large reward was maintained despite its uncertain delivery, suggesting a strong attraction for unitary rewards of great magnitude. Conclusion Uncertain delivery generated no aversion, when compared to delays producing an equivalent level of large-reward rarefaction. The PD task is suggested not to reflect impulsive behavior, and to generate patterns of choice that rather resemble the features of gambling. In summary, present data do indicate the need to interpret choice behavior in ID and PD protocols differently.

  18. Comparing Alternative Computer-Based Methods for Preventing Job Task Instructions

    Science.gov (United States)

    1988-02-01

    and accurate performance. The final study in this subcategory ( Coff , Schlesinger, & Parlog, 1969) compared the effects of presenting job task...electricity or electronics? No Yes . (If yes, specify the nature and type of schooling/training received; e.g., high school shop class...electricity or electronics? No Yes . (If yes, specify the nature and type of work experience received; e.g., part-time job in TV repair shop

  19. Peer-Implemented Time Delay Procedures on the Acquisition of Chained Tasks by Students with Moderate and Severe Disabilities

    Science.gov (United States)

    Godsey, Janet Read; Schuster, John W.; Lingo, Amy Shearer; Collins, Belva C.; Kleinert, Harold L.

    2008-01-01

    This study evaluated the effectiveness of and reliability of peer tutors implementing a constant time delay procedure when teaching four high school students with moderate and severe disabilities to prepare foods using picture recipes. We used a multiple probe design across subjects to determine the effectiveness of the peer tutor implemented…

  20. Depletion of cortical norepinephrine in rats by 6-hydroxydopamine does not impair performance of a delayed-nonmatching-to-sample task.

    Science.gov (United States)

    Koger, S M; Mair, R G

    1992-08-01

    Rats were trained on a spatial delayed-nonmatching-to-sample (DNMTS) task, matched for performance, and randomly assigned to treatment with dorsal noradrenergic bundle injections of either 6-hydroxydopamine, to deplete cortical norepinephrine (NE), or vehicle, to control for the effects of surgery. After recovery, there were no significant differences between the groups when retrained on the DNMTS task at retention intervals (RI) from 0.1 to 15.0 s. Furthermore, no differences were observed when rats were trained at a 6.0-s RI filled with distracting stimuli or when dummy information runs were added to increase proactive interference. These results demonstrate that depletion of cortical NE cannot account for the DNMTS performance deficits observed in rats recovered from pyrithiamine-induced thiamine deficiency (Knoth & Mair, 1991; Robinson & Mair, 1992).

  1. Destruction of central noradrenergic neurones with DSP4 impairs the acquisition of temporal discrimination but does not affect memory for duration in a delayed conditional discrimination task.

    Science.gov (United States)

    al-Zahrani, S S; al-Ruwaitea, A S; Ho, M Y; Bradshaw, C M; Szabadi, E

    1997-03-01

    This experiment examined the effect of destroying central noradrenergic neurones using the selective neurotoxin N-(2-chloroethyl)-n-ethyl-2-bromobenzylamine (DSP4) on the acquisition of a temporal discrimination and on memory for duration, using a delayed conditional discrimination task. In phase I, rats that had received systemic treatment with DSP4 and vehicle-treated control rats were trained in a series of discrete trials to press lever A following a 2-s presentation of a light stimulus, and lever B following an 8-s presentation of the same stimulus. Following stimulus offset, a response on a panel placed midway between the two levers was required to initiate lever presentation; a single response on either lever resulted in withdrawal of both levers and, in the case of a "correct" response, reinforcer delivery. Both groups acquired accurate discrimination, achieving 90% correct choices within 50 sessions; the DSP4-treated group acquired accurate performance more slowly than the control group. In phase II, delays were interposed between stimulus offset and lever presentation in 50% of the trials. In the absence of a delay, discriminative accuracy was lower in the DSP4-treated group than in the control group. Accuracy declined as a function of post-stimulus delay in both groups; both groups showed a delay-dependent bias towards responding on lever A ("choose-short" bias). Neither of these effects differed significantly between the two groups. The concentrations of noradrenaline in the parietal cortex and hippocampus were reduced by 90% and 89% in the DSP4-treated group, compared to the levels in the control group, but the levels of dopamine, 5-hydroxytryptamine and 5-hydroxyindoleacetic acid did not differ significantly between the groups. The results confirm the deleterious effect of DSP4 on the acquisition of temporal discrimination, but do not provide evidence for a role of the noradrenergic innervation of the hippocampus and neocortex in temporal working

  2. A novel spatial Delayed Non-Match to Sample (DNMS) task in the Göttingen minipig

    DEFF Research Database (Denmark)

    Nielsen, Thomas Rune; Kornum, Birgitte Rahbek; Moustgaard, Anette

    2009-01-01

    The pig (Sus scrofus) is a valuable animal for modeling human brain diseases. When evaluating animal models of many human brain disorders cognitive testing is crucial, but the pig's ability to learn the typical types of tasks used in neuropsychological testing of other species is largely unknown....

  3. The Social Attribution Task-Multiple Choice (SAT-MC): A Psychometric and Equivalence Study of an Alternate Form.

    Science.gov (United States)

    Johannesen, Jason K; Lurie, Jessica B; Fiszdon, Joanna M; Bell, Morris D

    2013-01-01

    The Social Attribution Task-Multiple Choice (SAT-MC) uses a 64-second video of geometric shapes set in motion to portray themes of social relatedness and intentions. Considered a test of "Theory of Mind," the SAT-MC assesses implicit social attribution formation while reducing verbal and basic cognitive demands required of other common measures. We present a comparability analysis of the SAT-MC and the new SAT-MC-II, an alternate form created for repeat testing, in a university sample (n = 92). Score distributions and patterns of association with external validation measures were nearly identical between the two forms, with convergent and discriminant validity supported by association with affect recognition ability and lack of association with basic visual reasoning. Internal consistency of the SAT-MC-II was superior (alpha = .81) to the SAT-MC (alpha = .56). Results support the use of SAT-MC and new SAT-MC-II as equivalent test forms. Demonstrating relatively higher association to social cognitive than basic cognitive abilities, the SAT-MC may provide enhanced sensitivity as an outcome measure of social cognitive intervention trials.

  4. Impulse control and restrained eating among young women: Evidence for compensatory cortical activation during a chocolate-specific delayed discounting task.

    Science.gov (United States)

    Dong, Debo; Wang, Yulin; Jackson, Todd; Chen, Shuaiyu; Wang, Yu; Zhou, Feng; Chen, Hong

    2016-10-01

    Theory and associated research indicate that people with elevated restrained eating (RE) scores have higher risk for binge eating, future bulimic symptom onset and weight gain. Previous imaging studies have suggested hyper-responsive reward brain area activation in response to food cues contributes to this risk but little is known about associated neural impulse control mechanisms, especially when considering links between depleted cognitive resources related to unsuccessful RE. Towards illuminating this issue, we used a chocolate-specific delayed discounting (DD) task to investigate relations between RE scores, behavior impulsivity, and corresponding neural impulse control correlates in a functional magnetic resonance imaging (fMRI) study of 27 young women. Specifically, participants were required to choose between more immediate, smaller versus delayed, larger hypothetical chocolate rewards following initial consumption of a chocolate. As predicted, RE scores were correlated positively with behavior impulse control levels. More critically, higher RE scores were associated with stronger activation in impulse control region, the dorsal-lateral prefrontal cortex (DLPFC) during the completion of difficult decision trials reflecting higher cognitive demands and resource depletion relative to easy decision trials. Exploratory analyses revealed a positive correlation between RE scores and activity in a reward system hub, the right striatum. Moreover, a positive correlation between left DLPFC and striatum activation was posited to reflect, in part, impulse control region compensation in response to stronger reward signal among women with RE elevations. Findings suggested impulse control lapses may contribute to difficulties in maintaining RE, particularly when cognitive demands are high.

  5. The Physics of Optimal Decision Making: A Formal Analysis of Models of Performance in Two-Alternative Forced-Choice Tasks

    Science.gov (United States)

    Bogacz, Rafal; Brown, Eric; Moehlis, Jeff; Holmes, Philip; Cohen, Jonathan D.

    2006-01-01

    In this article, the authors consider optimal decision making in two-alternative forced-choice (TAFC) tasks. They begin by analyzing 6 models of TAFC decision making and show that all but one can be reduced to the drift diffusion model, implementing the statistically optimal algorithm (most accurate for a given speed or fastest for a given…

  6. Alternative methods for dispoal of low-level radioactive wastes. Task 1. Description of methods and assessment of criteria. [Alternative methods are belowground vaults, aboveground vaults; earth mounded concrete bunkers, mined cavities, augered holes

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, R.D.; Miller, W.O.; Warriner, J.B.; Malone, P.G.; McAneny, C.C.

    1984-04-01

    The study reported herein contains the results of Task 1 of a four-task study entitled Criteria for Evaluating Engineered Facilities. The overall objective of this study is to ensure that the criteria needed to evaluate five alternative low-level radioactive waste (LLW) disposal methods are available to the Nuclear Regulatory Commission (NRC) and the Agreement States. The alternative methods considered are belowground vaults, aboveground vaults, earth mounded concrete bunkers, mined cavities, and augered holes. Each of these alternatives is either being used by other countries for low-level radioactive waste (LLW) disposal or is being considered by other countries or US agencies. In this report the performance requirements are listed, each alternative is described, the experience gained with its use is discussed, and the performance capabilities of each method are addressed. Next, the existing 10 CFR Part 61 Subpart D criteria with respect to paragraphs 61.50 through 61.53, pertaining to site suitability, design, operations and closure, and monitoring are assessed for applicability to evaluation of each alternative. Preliminary conclusions and recommendations are offered on each method's suitability as an LLW disposal alternative, the applicability of the criteria, and the need for supplemental or modified criteria.

  7. Alternative fabrication scheme to study effects of rework of nonconforming products and delayed differentiation on a multiproduct supply-chain system

    Directory of Open Access Journals (Sweden)

    Yuan-Shyi Peter Chiu

    2017-07-01

    Full Text Available This study uses an alternative fabrication scheme to study the effect of rework of nonconforming items and delayed differentiation on a multiproduct supply-chain system. Traditional economic production quantity model focuses on a single-product inventory system where all products made are assumed to be perfect quality and finished products are issued continuously. To increase machine utilization, lower quality costs in production, and reflect the real-world vendor-buyer integrated systems Chiu et al. (2016a [Chiu, Y-S.P., Kuo, J-S., Chiu, S. W., Hsieh, Y-T. (2016a. Effect of delayed differentiation on a multiproduct vendor–buyer integrated inventory system with rework. Advances in Production Engineering & Management, 11(4, 333-344.] employed a single-machine two-stage production scheme to study the effects of rework and delayed differentiation on a multi-product supply-chain system. With the intention of further reducing fabrication cycle time, this study considers an alternative two-machine two-stage fabrication scheme to re-explore the problem in Chiu et al. (2016a. Machine one solely produces all common parts for multiple end products. Then, machine two fabricates the customized multiproduct using a common cycle time strategy. Through the use of mathematical modeling and analyses, the optimal production cycle length and distribution policy are derived. Numerical examples are provided to demonstrate practical usage of the research results, and show its significant benefit in reducing fabrication cycle time compared to that obtained from prior studies that used different schemes.

  8. Eccentric exercise and delayed onset muscle soreness of the quadriceps induce adjustments in agonist-antagonist activity, which are dependent on the motor task.

    Science.gov (United States)

    Vila-Chã, C; Hassanlouei, H; Farina, D; Falla, D

    2012-02-01

    This study investigates the effects of eccentric exercise and delayed onset muscle soreness (DOMS) of the quadriceps on agonist-antagonist activity during a range of motor tasks. Ten healthy volunteers (age, mean ± SD, 24.9 ± 3.2 years) performed maximum voluntary contractions (MVC) and explosive isometric contractions of the knee extensors followed by isometric contractions at 2.5, 5, 10, 15, 20, and 30% MVC at baseline, immediately after and 24 h after eccentric exercise of the quadriceps. During each task, force of the knee extensors and surface EMG of the vasti and hamstrings muscles were recorded concurrently. Rate of force development (RFD) was computed from the explosive isometric contraction, and the coefficient of variation of the force (CoV) signal was estimated from the submaximal contractions. Twenty-four hours after exercise, the subjects rated their perceived pain intensity as 4.1 ± 1.2 (score out of 10). The maximum RFD and MVC of the knee extensors was reduced immediately post- and 24 h after eccentric exercise compared to baseline (average across both time points: 19.1 ± 17.1% and 11.9 ± 9.8% lower, respectively, P eccentric exercise (up to 66% higher than baseline, P exercise during the presence of DOMS (P exercise and was accompanied by increased antagonist EMG for the explosive contraction only. On the contrary, reduced force steadiness was accompanied by a general increase in EMG amplitude of the vasti muscles and was accompanied by increased antagonist activity, but only at higher force levels (>15% MVC). This study shows that eccentric exercise and subsequent DOMS of the quadriceps reduce the maximal force, rate of force development and force steadiness of the knee extensors, and is accompanied by different adjustments of agonist and antagonist muscle activities.

  9. Sub-millisecond firing synchrony of closely neighboring pyramidal neurons in hippocampal CA1 of rats during delayed non-matching to sample task

    Directory of Open Access Journals (Sweden)

    Susumu Takahashi

    2009-09-01

    Full Text Available Firing synchrony among neurons is thought to play functional roles in several brain regions. In theoretical analyses, firing synchrony among neurons within sub-millisecond precision is feasible to convey information. However, little is known about the occurrence and the functional significance of the sub-millisecond synchrony among closely neighboring neurons in the brain of behaving animals because of a technical issue: spikes simultaneously generated from closely neighboring neurons are overlapped in the extracellular space and are not easily separated. As described herein, using a unique spike sorting technique based on independent component analysis together with extracellular 12-channel multi-electrodes (dodecatrodes, we separated such overlapping spikes and investigated the firing synchrony among closely neighboring pyramidal neurons in the hippocampal CA1 of rats during a delayed non-matching to sample task. Results showed that closely neighboring pyramidal neurons in the hippocampal CA1 can co-fire with sub-millisecond precision. The synchrony generally co-occurred with the firing rate modulation in relation to both internal (retention and comparison and external (stimulus input and motor output events during the task. However, the synchrony occasionally occurred in relation to stimulus inputs even when rate modulation was clearly absent, suggesting that the synchrony is not simply accompanied with firing rate modulation and that the synchrony and the rate modulation might code similar information independently. We therefore conclude that the sub-millisecond firing synchrony in the hippocampus is an effective carrier for propagating information—as represented by the firing rate modulations—to downstream neurons.

  10. Delay Choice vs. Delay Maintenance: Different Measures of Delayed Gratification in Capuchin Monkeys (Cebus apella)

    Science.gov (United States)

    Addessi, Elsa; Paglieri, Fabio; Beran, Michael J.; Evans, Theodore A.; Macchitella, Luigi; De Petrillo, Francesca; Focaroli, Valentina

    2013-01-01

    Delaying gratification involves two components: (i) delay choice (selecting a delayed reward over an immediate one), and (ii) delay maintenance (sustaining the decision to delay gratification even if the immediate reward is available during the delay). In primates, two tasks most commonly have explored these components, the Intertemporal choice task and the Accumulation task. It is unclear whether these tasks provide equivalent measures of delay of gratification. Here, we compared the performance of the same capuchin monkeys, belonging to two study populations, between these tasks. We found only limited evidence of a significant correlation in performance. Consequently, in contrast to what is often assumed, our data provide only partial support to the hypothesis that these tasks provide equivalent measures of delay of gratification. PMID:23544770

  11. Functional connectivity between Layer 2/3 and Layer 5 neurons in prefrontal cortex of nonhuman primates during a delayed match-to-sample task.

    Science.gov (United States)

    Song, Dong; Opris, Ioan; Chan, Rosa H M; Marmarelis, Vasilis Z; Hampson, Robert E; Deadwyler, Sam A; Berger, Theodore W

    2012-01-01

    The prefrontal cortex (PFC) has been postulated to play critical roles in cognitive control and the formation of long-term memories. To gain insights into the neurobiological mechanism of such high-order cognitive functions, it is important to understand the input-output transformational properties of the PFC micro-circuitry. In this study, we identify the functional connectivity between the Layer 2/3 (input) neurons and the Layer 5 (output) neurons using a previously developed generalized Volterra model (GVM). Input-output spike trains are recorded from the PFCs of nonhuman primates performing a memory-dependent delayed match-to-sample task with a customized conformal ceramic multi-electrode array. The GVM describes how the input spike trains are transformed into the output spike trains by the PFC micro-circuitry and represents the transformation in the form of Volterra kernels. Results show that Layer 2/3 neurons have strong and transient facilitatory effects on the firings of Layer 5 neurons. The magnitude and temporal range of the input-output nonlinear dynamics are strikingly different from those of the hippocampal CA3-CA1. This form of functional connectivity may have important implications to understanding the computational principle of the PFC.

  12. Lesions of the dorsomedial striatum delay spatial learning and render cue-based navigation inflexible in a water maze task in mice.

    Science.gov (United States)

    Lee, Anni S; André, Jessica M; Pittenger, Christopher

    2014-01-01

    The dorsal striatum is involved in cue-based navigation strategies and in the development of habits. It has been proposed that striatum-dependent cued navigation competes with hippocampus-dependent spatial navigation in some circumstances. We have previously shown that large lesions of the dorsal striatum, as well as impairment of corticostriatal synaptic plasticity in transgenic mice, can enhance spatial learning in a water maze task, presumably by the disruption of competitive interference. However, the dorsal striatum is not a homogeneous structure; both anatomical considerations and experimental studies in various paradigms show that dorsomedial and dorsolateral striatum are functionally distinct, although there is no precise anatomical or neurochemical boundary between them. Here we investigated the effect of restricted excitotoxic lesions of dorsomedial striatum (DMS) on cued and spatial water maze learning. We find that dorsomedial striatal lesions delay spatial learning but permit cued learning. After cued learning, lesioned animals showed inflexible search, resulting in repeated visits to the escape platform-associated cue. These results support a role for the DMS in behavioral flexibility rather than in cue-based navigation.

  13. Excitotoxic lesions of the medial striatum delay extinction of a reinforcement color discrimination operant task in domestic chicks; a functional role of reward anticipation.

    Science.gov (United States)

    Ichikawa, Yoko; Izawa, Ei-Ichi; Matsushima, Toshiya

    2004-12-01

    To reveal the functional roles of the striatum, we examined the effects of excitotoxic lesions to the bilateral medial striatum (mSt) and nucleus accumbens (Ac) in a food reinforcement color discrimination operant task. With a food reward as reinforcement, 1-week-old domestic chicks were trained to peck selectively at red and yellow beads (S+) and not to peck at a blue bead (S-). Those chicks then received either lesions or sham operations and were tested in extinction training sessions, during which yellow turned out to be nonrewarding (S-), whereas red and blue remained unchanged. To further examine the effects on postoperant noninstrumental aspects of behavior, we also measured the "waiting time", during which chicks stayed at the empty feeder after pecking at yellow. Although the lesioned chicks showed significantly higher error rates in the nonrewarding yellow trials, their postoperant waiting time gradually decreased similarly to the sham controls. Furthermore, the lesioned chicks waited significantly longer than the controls, even from the first extinction block. In the blue trials, both lesioned and sham chicks consistently refrained from pecking, indicating that the delayed extinction was not due to a general disinhibition of pecking. Similarly, no effects were found in the novel training sessions, suggesting that the lesions had selective effects on the extinction of a learned operant. These results suggest that a neural representation of memory-based reward anticipation in the mSt/Ac could contribute to the anticipation error required for extinction.

  14. Effects of delay and probability combinations on discounting in humans.

    Science.gov (United States)

    Cox, David J; Dallery, Jesse

    2016-10-01

    To determine discount rates, researchers typically adjust the amount of an immediate or certain option relative to a delayed or uncertain option. Because this adjusting amount method can be relatively time consuming, researchers have developed more efficient procedures. One such procedure is a 5-trial adjusting delay procedure, which measures the delay at which an amount of money loses half of its value (e.g., $1000 is valued at $500 with a 10-year delay to its receipt). Experiment 1 (n=212) used 5-trial adjusting delay or probability tasks to measure delay discounting of losses, probabilistic gains, and probabilistic losses. Experiment 2 (n=98) assessed combined probabilistic and delayed alternatives. In both experiments, we compared results from 5-trial adjusting delay or probability tasks to traditional adjusting amount procedures. Results suggest both procedures produced similar rates of probability and delay discounting in six out of seven comparisons. A magnitude effect consistent with previous research was observed for probabilistic gains and losses, but not for delayed losses. Results also suggest that delay and probability interact to determine the value of money. Five-trial methods may allow researchers to assess discounting more efficiently as well as study more complex choice scenarios. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Identifying and individuating cognitive systems: a task-based distributed cognition alternative to agent-based extended cognition.

    Science.gov (United States)

    Davies, Jim; Michaelian, Kourken

    2016-08-01

    This article argues for a task-based approach to identifying and individuating cognitive systems. The agent-based extended cognition approach faces a problem of cognitive bloat and has difficulty accommodating both sub-individual cognitive systems ("scaling down") and some supra-individual cognitive systems ("scaling up"). The standard distributed cognition approach can accommodate a wider variety of supra-individual systems but likewise has difficulties with sub-individual systems and faces the problem of cognitive bloat. We develop a task-based variant of distributed cognition designed to scale up and down smoothly while providing a principled means of avoiding cognitive bloat. The advantages of the task-based approach are illustrated by means of two parallel case studies: re-representation in the human visual system and in a biomedical engineering laboratory.

  16. Considering Alternate Futures to Classify Off-Task Behavior as Emotion Self-Regulation: A Supervised Learning Approach

    Science.gov (United States)

    Sabourin, Jennifer L.; Rowe, Jonathan P.; Mott, Bradford W.; Lester, James C.

    2013-01-01

    Over the past decade, there has been growing interest in real-time assessment of student engagement and motivation during interactions with educational software. Detecting symptoms of disengagement, such as off-task behavior, has shown considerable promise for understanding students' motivational characteristics during learning. In this paper, we…

  17. Chronic infusions of GABA into the medial prefrontal cortex induce spatial alternation deficits in aged rats.

    Science.gov (United States)

    Meneses, S; Galicia, O; Brailowsky, S

    1993-10-21

    It has been proposed that functions associated with the prefrontal cortex could change as a consequence of aging. Previous experiments in young rats have demonstrated that anatomical lesions or chronic GABA infusions into this area produce deficits in spatial delayed alternation tasks. The present study examines the effect of chronic (7 days) GABA or saline infusion into the prefrontal cortex on the performance of delayed alternation task in old rats (24 months). The results suggested that aged rats needed more sessions to acquire the delayed alternation task. GABA infusions into the prefrontal cortex produced deficits in spatial alternation tasks similar to those previously observed in young rats. Performance rapidly recovered after the infusion period. Histological analysis showed similar lesion size in both groups. The results suggest that aged prefrontal cortex and/or related areas participating in the acquisition of the delayed alternation task are more sensitive to aging processes. Furthermore, the prefrontal cortex is important for the retention of a previously learned spatial delayed alternation task. The structures involved in functional recovery from these deficits appear to be fully functional in aged rats.

  18. Information Provision to the Visually Impaired in Alternative Formats in Nigeria: Are Public Libraries Up to the Task?

    Directory of Open Access Journals (Sweden)

    Adetoro, 'Niran

    2014-06-01

    Full Text Available Public libraries provide information to all persons and its users are the inhabitants of the community it serves. This may not be the reality in some cases as some category of persons may not be properly served by the public library. This study assesses the provision of information materials in alternative format, in terms of its availability, access and level of use by the visually impaired in public libraries in southwestern Nigeria. The study adopted survey research design. Four (4 public libraries in four states were purposively selected because they are the ones that provide alternative format for the use of a sizable number of the visually impaired. Complete enumeration was used to capture all the 166 registered users of the libraries through the use of observations checklist and interview schedule. Data from 69.2% of the 166 visually impaired persons that were interviewed, and the observations made were analyzed. The result reveals that alternative formats availability were inadequate and, e-resources were not available while access to formats and information desired by the users were limited. Braille is the most utilized format; audio materials and large prints were seldom used. The demand for alternative formats is high but it is not related to level of use of materials. Provision of information materials in alternative formats for the visually impaired in public libraries cannot support the needs of the visually impaired; it requires intervention from all stakeholders. The study recommends improved investment and funding for public libraries and services to persons with disabilities.

  19. Low-dose memantine induced working memory improvement in the allothetic place avoidance alternation task (APAAT in young adult male rats.

    Directory of Open Access Journals (Sweden)

    Malgorzata Julita Wesierska

    2013-12-01

    Full Text Available N-methyl-D-aspartate receptors (NMDAR are involved in neuronal plasticity. To assess their role simultaneously in spatial working memory and non-cognitive learning, we used NMDAR antagonists and the Allothetic Place Avoidance Alternation Task (APAAT. In this test rats should avoid entering a place where shocks were presented on a rotating arena which requires cognitive coordination for the segregation of stimuli. The experiment took place 30 min after intraperitoneal injection of memantine (5; 10; 20 mg/kg b.w.: MemL, MemM, MemH respectively and (+MK-801 (0.1; 0.2; 0.3 mg/kg b.w.: MK-801L, MK-801M, MK-801H respectively. Rats from the control group were intact or injected with saline (0.2 ml/kg. Over three consecutive days the rats underwent habituation, two avoidance training intervals with shocks, and a retrieval test. The shock sector was alternated daily. The after-effects of the agents were tested on Day21. Rats treated with low dose memantine presented a longer maximum time avoided and fewer entrances than the MemH, MK-801M, MK-801H and Control rats. The shocks per entrances ratio, used as an index of cognitive skill learning, showed skill improvement after D1, except for rats treated by high doses of the agents. The activity levels, indicated by the distance walked, were higher for the groups treated with high doses of the agents. On D21 the MK801H rats performed the memory task better than the MemH rats, whereas the rats’ activity depended on condition, not on the group factor. These results suggest that in naïve rats mild NMDAR blockade by low-dose memantine improves working memory related to a highly challenging task.

  20. JV Task 109 - Risk Assessment and Feasibility of Remedial Alternatives for Coal Seam at Garrison, North Dakota

    Energy Technology Data Exchange (ETDEWEB)

    Jarda Solc

    2008-01-01

    The Energy & Environmental Research Center (EERC) conducted an evaluation of alternative technologies for remediation of hydrocarbon-contaminated coal seam, including impacted soils and groundwater in Garrison, North Dakota. Geotechnical characteristics of the impacted fractured coal seam provide for rapid off-site contaminant transport, with the currently identified impacted zone covering an area of about 40 acres. Regardless of the exposure mechanism (free, dissolved, or vapor phase), results of laboratory tests confirmed secondary release of gasoline-based compounds from contaminated coal to water reaching concentrations documented from the impacted areas. Coal laboratory tests confirmed low risks associated with spontaneous ignition of gasoline-contaminated coal. High contaminant recovery efficiency for the vacuum-enhanced recovery pilot tests conducted at three selected locations confirmed its feasibility for full-scale remediation. A total of 3500 gallons (13.3 m{sup 3}) of contaminated groundwater and over 430,000 ft{sup 3} (12,200 m{sup 3}) of soil vapor were extracted during vacuum-enhanced recovery testing conducted July 17-24, 2007, resulting in the removal of about 1330 lb (603 kg) of hydrocarbons, an equivalent of about 213 gallons of product. The summary of project activities is as follows: (1) Groundwater and vapor monitoring for existing wells, including domestic wells, conducted on a monthly basis from December 12, 2006, to June 6, 2007. This monitoring activity conducted prior to initiation of the EERC field investigation was requested by NDDH in a letter dated December 1, 2006. (2) Drilling of 20 soil borings, including installation of extraction and monitoring wells conducted April 30-May 4 and May 14-18, 2007. (3) Groundwater sampling and water-table monitoring conducted June 11-13, 2007. (4) Evaluation of the feasibility of using a camera survey for delineation of mining voids conducted May 16 and September 10-11, 2007. (5) Survey of all wells

  1. New York Airports Data Package Number 5, John F. Kennedy International Airport, La Guardia Airport. Airport Improvement Task Force Delay Studies.

    Science.gov (United States)

    1979-03-01

    8217 ’ :".- ?" ’: " , ... "...." " ’ ’. .. , 27 FIGMM 2C AVERAGE TAXIWAY DELAYS 󈧰 o 2 & Delat es h0 0-- i5 16 17 18 19 20 21 22 23 Hour Beginning FIGURE 2D

  2. Delayed habituation of the skin-conductance orienting response correlates with impaired performance on the Wisconsin Card Sorting Task in schizophrenia.

    Science.gov (United States)

    Schiffer, R A; Sigal, M; Mintz, M

    1996-11-15

    The skin-conductance orienting response (SCOR) in schizophrenia is often characterized by either nonresponding or delayed habituation to repeated nonsignal tones. These abnormalities are poorly related to other dimensions of schizophrenia. In the present study, we confirmed that about 50% of patients with chronic schizophrenia are SCOR nonresponders. Nonresponders, however, did not differ from responders on postmorbid psychiatric or pharmacological course, and we therefore could not confirm the hypothesis that course of illness follows a more marked pattern of increasing severity in nonresponders. Performance on the Wisconsin Card Sorting Test (WCST) was particularly poor in a subgroup of responders who exhibited either delayed habituation and/or dishabituation of SCORs to tones applied after a short rest period. It is possible that pathology of the prefrontal cortex mediates the SCOR abnormalities that characterize schizophrenic patients who perform poorly on the WCST.

  3. Delayed fracture of silicon: Silicon sheet growth development for the large area silicon sheet task of the low cost silicon solar array project

    Science.gov (United States)

    Chen, T. J.; Knapp, W. J.

    1978-01-01

    Bar specimens were cut from ingots of single crystal silicon, and acid etched prior to testing. Artificial surface flaws were introduced in specimens by indentation with a Knoop hardness tester. The specimens were loaded in four-point bending to 95 percent of the nominal fracture stress, while keeping the surface area, containing the flaw, wet with test liquids. No evidence of delayed fracture, and, therefore stress corrosion, of single crystal silicon was observed for liquid environments including water, acetone, and aqueous solutions of NaCl, NH4OH, and HNO3, when tested with a flaw parallel to a (110) surface. The fracture toughness was calculated.

  4. A novel variable delay Go/No-Go task to study attention, motivation and working memory in the head-fixed rodent [v2; ref status: indexed, http://f1000r.es/1sn

    Directory of Open Access Journals (Sweden)

    Samuel D Dolzani

    2014-03-01

    Full Text Available In order to parse the causal elements underlying complex behaviors and decision-making processes, appropriate behavioral methods must be developed and used in concurrence with molecular, pharmacological, and electrophysiological approaches. Presented is a protocol for a novel Go/No-Go behavioral paradigm to study the brain attention and motivation/reward circuitry in awake, head-restrained rodents. This experimental setup allows: (1 Pharmacological and viral manipulation of various brain regions via targeted guide cannula; (2 Optogenetic cell-type specific activation and silencing with simultaneous electrophysiological recording and; (3 Repeated electrophysiological single and multiple unit recordings during ongoing behavior. The task consists of three components. The subject first makes an observing response by initiating a trial by lever pressing in response to distinctive Go or No-Go tones.  Then, after a variable delay period, the subject is presented with a challenge period cued by white noise during which they must respond with a lever press for the Go condition or withhold from lever pressing for the duration of the cue in the No-Go condition. After correctly responding during the challenge period (Challenge and a brief delay, a final reward tone of the same frequency as the initiation tone is presented and sucrose reward delivery is available and contingent upon lever pressing. Here, we provide a novel procedure and validating data set that allows researchers to study and manipulate components of behavior such as attention, motivation, impulsivity, and reward-related working memory during an ongoing operant behavioral task while limiting interference from non task-related behaviors.

  5. Spectral Entropy Can Predict Changes of Working Memory Performance Reduced by Short-Time Training in the Delayed-Match-to-Sample Task

    Directory of Open Access Journals (Sweden)

    Yin Tian

    2017-08-01

    Full Text Available Spectral entropy, which was generated by applying the Shannon entropy concept to the power distribution of the Fourier-transformed electroencephalograph (EEG, was utilized to measure the uniformity of power spectral density underlying EEG when subjects performed the working memory tasks twice, i.e., before and after training. According to Signed Residual Time (SRT scores based on response speed and accuracy trade-off, 20 subjects were divided into two groups, namely high-performance and low-performance groups, to undertake working memory (WM tasks. We found that spectral entropy derived from the retention period of WM on channel FC4 exhibited a high correlation with SRT scores. To this end, spectral entropy was used in support vector machine classifier with linear kernel to differentiate these two groups. Receiver operating characteristics analysis and leave-one out cross-validation (LOOCV demonstrated that the averaged classification accuracy (CA was 90.0 and 92.5% for intra-session and inter-session, respectively, indicating that spectral entropy could be used to distinguish these two different WM performance groups successfully. Furthermore, the support vector regression prediction model with radial basis function kernel and the root-mean-square error of prediction revealed that spectral entropy could be utilized to predict SRT scores on individual WM performance. After testing the changes in SRT scores and spectral entropy for each subject by short-time training, we found that 16 in 20 subjects’ SRT scores were clearly promoted after training and 15 in 20 subjects’ SRT scores showed consistent changes with spectral entropy before and after training. The findings revealed that spectral entropy could be a promising indicator to predict individual’s WM changes by training and further provide a novel application about WM for brain–computer interfaces.

  6. A Novel Connectionist Network for Solving Long Time-Lag Prediction Tasks

    Science.gov (United States)

    Johnson, Keith; MacNish, Cara

    Traditional Recurrent Neural Networks (RNNs) perform poorly on learning tasks involving long time-lag dependencies. More recent approaches such as LSTM and its variants significantly improve on RNNs ability to learn this type of problem. We present an alternative approach to encoding temporal dependencies that associates temporal features with nodes rather than state values, where the nodes explicitly encode dependencies over variable time delays. We show promising results comparing the network's performance to LSTM variants on an extended Reber grammar task.

  7. Magnetic bearing optical delay line

    NARCIS (Netherlands)

    Dool, T.C. van den; Kamphues, F.G.; Fouss, B.; Henrioulle, K.; Hogenhuis, H.

    2004-01-01

    TNO TPD, in close cooperation with Micromega-Dynamics and Dutch Space, has developed an advanced Optical Delay Line (ODL) for use in PRIMA, GENIE and other ground based interferometers. The delay line design is modular and flexible, which makes scaling for other applications a relatively easy task.

  8. Delayed Puberty

    DEFF Research Database (Denmark)

    Kolby, Nanna; Busch, Alexander Siegfried; Juul, Anders

    2017-01-01

    Delayed puberty can be a source of great concern and anxiety, although it usually is caused by a self-limiting variant of the normal physiological timing named constitutional delay of growth and puberty (CDGP). Delayed puberty can, however, also be the first presentation of a permanent condition ...... mineral density) and psychological (e.g., low self-esteem) and underline the importance of careful clinical assessment of the patients.......Delayed puberty can be a source of great concern and anxiety, although it usually is caused by a self-limiting variant of the normal physiological timing named constitutional delay of growth and puberty (CDGP). Delayed puberty can, however, also be the first presentation of a permanent condition...

  9. Delayed fission

    Energy Technology Data Exchange (ETDEWEB)

    Hatsukawa, Yuichi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-07-01

    Delayed fission is a nuclear decay process that couples {beta} decay and fission. In the delayed fission process, a parent nucleus undergoes {beta} decay and thereby populates excited states in the daughter. If these states are of energies comparable to or greater than the fission barrier of the daughter, then fission may compete with other decay modes of the excited states in the daughter. In this paper, mechanism and some experiments of the delayed fission will be discussed. (author)

  10. The usefulness of fungicide mixtures and alternation for delaying the selection for resistance in populations of Mycosphaerella graminicola on winter wheat: a modeling analysis.

    Science.gov (United States)

    Hobbelen, P H F; Paveley, N D; Oliver, R P; van den Bosch, F

    2013-07-01

    A fungicide resistance model (reported and tested previously) was amended to describe the development of resistance in Mycosphaerella graminicola populations in winter wheat (Triticum aestivum) crops in two sets of fields, connected by spore dispersal. The model was used to evaluate the usefulness of concurrent, alternating, or mixture use of two high-resistance-risk fungicides as resistance management strategies. We determined the effect on the usefulness of each strategy of (i) fitness costs of resistance, (ii) partial resistance to fungicides, (iii) differences in the dose-response curves and decay rates between fungicides, and (iv) different frequencies of the double-resistant strain at the start of a treatment strategy. Parameter values for the quinine outside inhibitor pyraclostrobin were used to represent two fungicides with differing modes of action. The effectiveness of each strategy was quantified as the maximum number of growing seasons that disease was effectively controlled in both sets of fields. For all scenarios, the maximum effective lives achieved by the use of the strategies were in the order mixtures ≥ alternation ≥ concurrent use. Mixtures were of particular benefit where the pathogen strain resistant to both modes of action incurred a fitness penalty or was present at a low initial frequency.

  11. A methodological note on evaluating performance in a sustained-attention-to-response task.

    Science.gov (United States)

    Seli, Paul; Jonker, Tanya R; Solman, Grayden J F; Cheyne, James Allan; Smilek, Daniel

    2013-06-01

    We evaluated the influence of speed-accuracy trade-offs on performance in the sustained attention to response task (SART), a task often used to evaluate the effectiveness of techniques designed to improve sustained attention. In the present study, we experimentally manipulated response delay in a variation of the SART and found that commission errors, which are commonly used as an index of lapses in sustained attention, were a systematic function of manipulated differences in response delay. Delaying responses to roughly 800 ms after stimulus onset reduced commission errors substantially. We suggest the possibility that any technique that affects response speed will indirectly alter error rates independently of improvements in sustained attention. Investigators therefore need to carefully explore, report, and correct for changes in response speed that accompany improvements in performance or, alternatively, to employ tasks that control for response speed.

  12. Does Digital Game-Based Learning Improve Student Time-on-Task Behavior and Engagement in Comparison to Alternative Instructional Strategies?

    Science.gov (United States)

    Schaaf, Ryan

    2012-01-01

    Digital Game-Based Learning (DGBL) activities were examined in comparison with effective, research-based learning strategies to observe any difference in student engagement and time-on task behavior. Experimental and control groups were randomly selected amongst the intermediate elementary school students ages 8 to 10 years old. Student…

  13. Caffeine improves anticipatory processes in task switching

    NARCIS (Netherlands)

    Tieges, Zoe; Snel, Jan; Kok, Albert; Wijnen, Jasper G.; Lorist, Monicque M.; Ridderinkhof, K. Richard

    We studied the effects of moderate amounts of caffeine on task switching and task maintenance using mixed-task (AABB) blocks, in which participants alternated predictably between two tasks, and single-task (AAAA, BBBB) blocks. Switch costs refer to longer reaction times (RT) on task switch trials

  14. Caffeine improves anticipatory processes in task switching

    NARCIS (Netherlands)

    Tieges, Zoe; Snel, Jan; Kok, Albert; Wijnen, Jasper G.; Lorist, Monicque M.; Ridderinkhof, K. Richard

    2006-01-01

    We studied the effects of moderate amounts of caffeine on task switching and task maintenance using mixed-task (AABB) blocks, in which participants alternated predictably between two tasks, and single-task (AAAA, BBBB) blocks. Switch costs refer to longer reaction times (RT) on task switch trials (e

  15. Lowering of the firing voltage and reducing of the discharge delay time in alternating current plasma display panels by a discontinuous spin-coated LaB6 film on the MgO protective layer

    Directory of Open Access Journals (Sweden)

    Jiang Deng

    2014-03-01

    Full Text Available A spin coated LaB6 discontinuous film is covered on MgO protective layer to improve the discharge performance of alternating current plasma display panels. Under the premise of high transmittance of more than 90%, a very small amount of polycrystal LaB6 powders added in an organic solvent are chosen as the coating solution. The discharge characteristics results show that with 250 torr 5% Xe-Ne pressure, the firing voltage and discharge delay time of the test panel with LaB6/MgO double protective layer are decreased by 13.4% and 36.5%, respectively, compared with that of conventional MgO protective layer, likely owing to the low work function of LaB6. Furthermore, the aging time of the proposed structure is comparable to that of pure MgO protective layer. Therefore, it will not increase the production costs and is highly suitable to be applied for alternating current plasma display panels with low electrical power consumption.

  16. Lowering of the firing voltage and reducing of the discharge delay time in alternating current plasma display panels by a discontinuous spin-coated LaB{sub 6} film on the MgO protective layer

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Jiang, E-mail: dj78291@163.com [School of Physical Electronic, University of Electronic Science and Technology of China, No.4, Section 2, Jianshe North Road, 610054 Chengdu (China); Zeng, Baoqing [School of Physical Electronic, University of Electronic Science and Technology of China, No.4, Section 2, Jianshe North Road, 610054 Chengdu (China); Zhongshan Institute, University of Electronic Science and Technology of China, 528402 zhongshan (China); Wang, Xiaoju; Lin, Zulun; Qi, Kangcheng; Cao, Guichuan [School of Opto-electronic Information, University of Electronic Science and Technology of China, No.4, Section 2, Jianshe North Road, 610054 Chengdu (China)

    2014-03-15

    A spin coated LaB{sub 6} discontinuous film is covered on MgO protective layer to improve the discharge performance of alternating current plasma display panels. Under the premise of high transmittance of more than 90%, a very small amount of polycrystal LaB{sub 6} powders added in an organic solvent are chosen as the coating solution. The discharge characteristics results show that with 250 torr 5% Xe-Ne pressure, the firing voltage and discharge delay time of the test panel with LaB{sub 6}/MgO double protective layer are decreased by 13.4% and 36.5%, respectively, compared with that of conventional MgO protective layer, likely owing to the low work function of LaB{sub 6.} Furthermore, the aging time of the proposed structure is comparable to that of pure MgO protective layer. Therefore, it will not increase the production costs and is highly suitable to be applied for alternating current plasma display panels with low electrical power consumption.

  17. So/sub 2/ reduction in non-utility combustion sources: technical and economic comparison of alternatives. Final task report, May 1974--Sep 1975

    Energy Technology Data Exchange (ETDEWEB)

    Choi, P.S.K.; Kropp, E.L.; Ballantyne, W.E.; Anastas, M.Y.; Putnam, A.A.

    1975-10-01

    The report gives results of an analysis of non-utility combustion (NUC) sources for various size classes and fuel types with respect to the significance of SO/sub 2/ emissions. Technical and economic comparisons of various SO/sub 2/ control alternatives were made for the important size classes and fuel types. Categories of alternatives included are: physical cleaning of coal, coal gasification, coal liquefaction, fluidized-bed combustion of coal, and flue gas desulfurization. For small size classes of NUC sources, applicabilities of package sorption systems are reviewed. (GRA)

  18. NASAP: a computer code for the evaluation of the Non-proliferation Alternative Systems Assessment Program concepts. Final report in support of Task 2. [PWR; BWR

    Energy Technology Data Exchange (ETDEWEB)

    Maul, B.A.

    1979-09-01

    The Non-Proliferation Alternative Systems Assessment Program (NASAP) computer code was developed to calculate the LWR and NASAP choice reactor cost through an arbitrary year T/sub N/. The final cost is arrived at by calculation of cost contributory factors for both LWR and NASAP choice reactors.

  19. Synthesis of dimethyl ether and alternative fuels in the liquid phase from coal-derived synthesis gas. Task 3.2: Screen novel catalyst systems; Task 3.3:, Evaluation of the preferred catalyst system

    Energy Technology Data Exchange (ETDEWEB)

    Underwood, R.P.

    1993-01-01

    As part of the DOE-sponsored contract ``Synthesis of Dimethyl Ether and Alternative Fuels in the Liquid Phase from Coal-Derived Syngas`` experimental evaluations of the one-step synthesis of alternative fuels were carried out. The objective of this work was to develop novel processes for converting coal-derived syngas to fuels or fuel additives. Building on a technology base acquired during the development of the Liquid Phase Methanol (LPMEOH) process, this work focused on the development of slurry reactor based processes. The experimental investigations, which involved bench-scale reactor studies, focused primarily on three areas: (1) One-step, slurry-phase syngas conversion to hydrocarbons or methanol/hydrocarbon mixtures using a mixture of methanol synthesis catalyst and methanol conversion catalyst in the same slurry reactor. (2) Slurry-phase conversion of syngas to mixed alcohols using various catalysts. (3) One-step, slurry-phase syngas conversion to mixed ethers using a mixture of mixed alcohols synthesis catalyst and dehydration catalyst in the same slurry reactor. The experimental results indicate that, of the three types of processes investigated, slurry phase conversion of syngas to mixed alcohols shows the most promise for further process development. Evaluations of various mixed alcohols catalysts show that a cesium-promoted Cu/ZnO/Al{sub 2}O{sub 3} methanol synthesis catalyst, developed in Air Products` laboratories, has the highest performance in terms of rate and selectivity for C{sub 2+}-alcohols. In fact, once-through conversion at industrially practical reaction conditions yielded a mixed alcohols product potentially suitable for direct gasoline blending. Moreover, an additional attractive aspect of this catalyst is its high selectivity for branched alcohols, potential precursors to iso-olefins for use in etherification.

  20. Follow-up to the ECVAM prevalidation study on in vitro tests for acute skin irritation. The European Centre for the Validation of Alternative Methods Skin Irritation Task Force report 2.

    Science.gov (United States)

    Zuang, Valérie; Balls, Michael; Botham, Philip A; Coquette, Alain; Corsini, Emanuela; Curren, Rodger D; Elliott, Graham R; Fentem, Julia H; Heylings, Jon R; Liebsch, Manfred; Medina, Jesús; Roguet, Roland; van de Sandt, Johannes J M; Wiemann, Christianne; Worth, Andrew P

    2002-01-01

    The European Centre for the Validation of Alternative Methods (ECVAM) Skin Irritation Task Force was established in 1996, to review the status of the development and validation of alternative tests for skin irritation and corrosion, and to identify appropriate non-animal tests for predicting human skin irritation that were sufficiently well-developed to be prevalidated and validated by ECVAM. The EpiDerm method, based on a reconstituted human skin model, was proposed as being sufficiently well advanced to enter a prevalidation (PV) study. Based on a review of test protocols, prediction models (PMs), and data submitted by test developers on ten specified chemicals, with 20% sodium lauryl sulphate as a reference standard, the task force recommended the inclusion of four other tests: EPISKIN and PREDISKIN, based on reconstituted human epidermis or on human skin; the non-perfused pig-ear test, based on pig skin; and the skin integrity function test (SIFT), with ex vivo mouse skin. The prevalidation study on these methods was funded by ECVAM, and took place during 1999-2000. The outcome of the PV study was that none of the methods was ready to enter a formal validation study, and that the protocols and PMs of the methods had to be improved in order to increase their predictive abilities. Improved protocols and PMs for the EpiDerm and EPISKIN methods, the pig ear test, and the SIFT were presented at an extended Task Force meeting held in May 2001. It was agreed that, in the short term, the performance of the revised and harmonised EpiDerm and EPISKIN methods, as well as the modified SIFT, should be evaluated in a further study with a new set of 20 test chemicals. In addition, it was decided that the SIFT and the pig ear test would be compared to see if common endpoints (transepidermal water loss, methyl green-pyronine stain) could be identified.

  1. Reward type and behavioural patterns predict dogs’ success in a delay of gratification paradigm

    Science.gov (United States)

    Brucks, Désirée; Soliani, Matteo; Range, Friederike; Marshall-Pescini, Sarah

    2017-01-01

    Inhibiting an immediate behaviour in favour of an alternative but more advantageous behaviour has been linked to individual success in life, especially in humans. Dogs, which have been living in the human environment for thousands of years, are exposed to daily situations that require inhibition different in context from other non-domesticated species. One task regularly used to study inhibitory control is the delay of gratification task, which requires individuals to choose between an immediate option of lower value and a delayed option of higher value. We tested sixteen dogs in a non-social delay of gratification task, conducting two different conditions: a quality and a quantity condition. While the majority of dogs failed to wait for more than 10 s, some dogs tolerated delays of up to 140 s, while one dog waited for 15 minutes. Moreover, dogs had more difficulties to wait if the reward increased in terms of quantity than quality. Interestingly, dogs were able to anticipate the delay duration and some dogs developed behavioural patterns that predicted waiting, which seems similar in some respects to ‘coping-strategies’ found in children, chimpanzees and parrots. Our results indicate that strategies to cope with impulsivity seem to be consistent and present across animal taxa. PMID:28272409

  2. Controlling flow time delays in flexible manufacturing cells

    NARCIS (Netherlands)

    Slomp, J.; Caprihan, R.; Bokhorst, J. A. C.

    2009-01-01

    Flow time delays in Flexible Manufacturing Cells (FMCs) are caused by transport and clamping/reclamping activities. This paper shows how dynamic scheduling parameters may control the flow times of jobs and the available task windows for flow time delays.

  3. Recommendations to the NRC for review criteria for alternative methods of low-level radioactive waste disposal: Task 2a, Below-ground vaults

    Energy Technology Data Exchange (ETDEWEB)

    Denson, R.H.; Bennett, R.D.; Wamsley, R.M.; Bean, D.L.; Ainsworth, D.L.

    1987-12-01

    The US Army Engineer Waterways Experiment Station (WES) and the US Army Engineer Division, Huntsville (HNDED) have developed general design criteria and specific design review criteria for the below-ground vault (BGV) alternative method of low-level radioactive waste (LLW) disposal. A BGV is a reinforced concrete vault (floor, walls, and roof) placed underground below the frost line, and above the water table, surrounded by filter blanket and drainage zones and covered with a low permeability earth layer and top soil with vegetation. Eight major review criteria categories have been developed ranging from the loads imposed on the BGV structure through material quality and durability considerations. Specific design review criteria have been developed in detail for seven of the eight major categories. 59 refs., 14 figs., 2 tabs.

  4. Recommendations to the NRC for review criteria for alternative methods of low-level radioactive waste disposal: Task 2b: Earth-mounded concrete bunkers

    Energy Technology Data Exchange (ETDEWEB)

    Denson, R.H.; Bennett, R.D.; Wamsley, R.M.; Bean, D.L.; Ainsworth, D.L.

    1988-01-01

    The US Army Engineers Waterways Experiment Station (WES) and US Army Engineer Division, Huntsville (HNDED) have developed general design criteria and specific design review criteria for the earth-mounded concrete bunker (EMCB) alternative method of low-level radioactive waste (LLW) disposal. An EMCB is generally described as a reinforced concrete vault placed below grade, underneath a tumulus, surrounded by filter-blanket and drainage zones. The tumulus is covered over with a low permeability cover layer and top soil with vegetation. Eight major review criteria categories have been developed ranging from the loads imposed on the EMCB structure through material quality and durability considerations. Specific design review criteria have been developed in detail for each of the eight major categories. 63 refs., 13 figs., 2 tabs.

  5. Reward type and behavioural patterns predict dogs' success in a delay of gratification paradigm

    National Research Council Canada - National Science Library

    Désirée Brucks; Matteo Soliani; Friederike Range; Sarah Marshall-pescini

    2017-01-01

    .... One task regularly used to study inhibitory control is the delay of gratification task, which requires individuals to choose between an immediate option of lower value and a delayed option of higher value...

  6. Impulsivity in spontaneously hypertensive rats: Within-subjects comparison of sensitivity to delay and to amount of reinforcement.

    Science.gov (United States)

    Orduña, Vladimir; Mercado, Eduardo

    2017-06-15

    Previous research has shown that spontaneously hypertensive rats (SHR) display higher levels of impulsive choice behavior, which is accompanied by a higher sensitivity to the delay of reinforcement, and by a normal sensitivity to the amount of reinforcement. Because those results were based on three different samples of subjects, in the present report we evaluated these three processes in the same individuals. SHR and WIS rats were exposed to concurrent-chains schedules in which the terminal links were manipulated to assess impulsivity, sensitivity to delay, and sensitivity to amount. For exploring impulsivity, a terminal link was associated with a small reinforcer (1 pellet) delivered after a short delay (2s) while the other terminal link was associated with a larger reinforcer (4 pellets) delivered after a longer delay (28s). For assessing sensitivity to delay, both alternatives delivered the same amount of reinforcement (1 pellet) and the only difference between them was in the delay before reinforcement delivery (2s vs 28s). For assessing sensitivity to amount, both alternatives were associated with the same delay (15s), but the alternatives differed in the amount of reinforcement (1 vs 4 pellets). In addition to replicating previously observed effects within-subjects, we were interested in analyzing different aspects of the regularity of rats' actions in the choice task. The results confirmed that previous findings were not a consequence of between-group differences: SHR were more impulsive and more sensitive to delay, while their sensitivity to amount was normal. Analyses of response regularity indicated that SHR subjects were more periodic in their responses to levers and in their feeder entries, had a higher number of short-duration bouts of responding, and made a substantially higher number of switches between the alternatives. We discuss the potential implications of these findings for the possible behavioral mechanisms driving the increased sensitivity

  7. Alternative time representation in dopamine models.

    Science.gov (United States)

    Rivest, François; Kalaska, John F; Bengio, Yoshua

    2010-02-01

    Dopaminergic neuron activity has been modeled during learning and appetitive behavior, most commonly using the temporal-difference (TD) algorithm. However, a proper representation of elapsed time and of the exact task is usually required for the model to work. Most models use timing elements such as delay-line representations of time that are not biologically realistic for intervals in the range of seconds. The interval-timing literature provides several alternatives. One of them is that timing could emerge from general network dynamics, instead of coming from a dedicated circuit. Here, we present a general rate-based learning model based on long short-term memory (LSTM) networks that learns a time representation when needed. Using a naïve network learning its environment in conjunction with TD, we reproduce dopamine activity in appetitive trace conditioning with a constant CS-US interval, including probe trials with unexpected delays. The proposed model learns a representation of the environment dynamics in an adaptive biologically plausible framework, without recourse to delay lines or other special-purpose circuits. Instead, the model predicts that the task-dependent representation of time is learned by experience, is encoded in ramp-like changes in single-neuron activity distributed across small neural networks, and reflects a temporal integration mechanism resulting from the inherent dynamics of recurrent loops within the network. The model also reproduces the known finding that trace conditioning is more difficult than delay conditioning and that the learned representation of the task can be highly dependent on the types of trials experienced during training. Finally, it suggests that the phasic dopaminergic signal could facilitate learning in the cortex.

  8. A Mathematical Model of Levodopa Medication Effect on Basal Ganglia in Parkinson's Disease: An Application to the Alternate Finger Tapping Task.

    Science.gov (United States)

    Baston, Chiara; Contin, Manuela; Calandra Buonaura, Giovanna; Cortelli, Pietro; Ursino, Mauro

    2016-01-01

    Malfunctions in the neural circuitry of the basal ganglia (BG), induced by alterations in the dopaminergic system, are responsible for an array of motor disorders and milder cognitive issues in Parkinson's disease (PD). Recently Baston and Ursino (2015a) presented a new neuroscience mathematical model aimed at exploring the role of basal ganglia in action selection. The model is biologically inspired and reproduces the main BG structures and pathways, modeling explicitly both the dopaminergic and the cholinergic system. The present work aims at interfacing this neurocomputational model with a compartmental model of levodopa, to propose a general model of medicated Parkinson's disease. Levodopa effect on the striatum was simulated with a two-compartment model of pharmacokinetics in plasma joined with a motor effect compartment. The latter is characterized by the levodopa removal rate and by a sigmoidal relationship (Hill law) between concentration and effect. The main parameters of this relationship are saturation, steepness, and the half-maximum concentration. The effect of levodopa is then summed to a term representing the endogenous dopamine effect, and is used as an external input for the neurocomputation model; this allows both the temporal aspects of medication and the individual patient characteristics to be simulated. The frequency of alternate tapping is then used as the outcome of the whole model, to simulate effective clinical scores. Pharmacokinetic-pharmacodynamic modeling was preliminary performed on data of six patients with Parkinson's disease (both "stable" and "wearing-off" responders) after levodopa standardized oral dosing over 4 h. Results show that the model is able to reproduce the temporal profiles of levodopa in plasma and the finger tapping frequency in all patients, discriminating between different patterns of levodopa motor response. The more influential parameters are the Hill coefficient, related with the slope of the effect sigmoidal

  9. Activation of dorsal raphe serotonin neurons is necessary for waiting for delayed rewards.

    Science.gov (United States)

    Miyazaki, Kayoko W; Miyazaki, Katsuhiko; Doya, Kenji

    2012-08-01

    The forebrain serotonergic system is a crucial component in the control of impulsive behaviors. We previously reported that the activity of serotonin neurons in the midbrain dorsal raphe nucleus increased when rats performed a task that required them to wait for delayed rewards. However, the causal relationship between serotonin neural activity and the tolerance for the delayed reward remained unclear. Here, we test whether the inhibition of serotonin neural activity by the local application of the 5-HT(1A) receptor agonist 8-hydroxy-2-(di-n-propylamino) tetralin in the dorsal raphe nucleus impairs rats' tolerance for delayed rewards. Rats performed a sequential food-water navigation task that required them to visit food and water sites alternately via a tone site to get rewards at both sites after delays. During the short (2 s) delayed reward condition, the inhibition of serotonin neural activity did not significantly influence the numbers of reward choice errors (nosepoke at an incorrect reward site following a conditioned reinforcer tone), reward wait errors (failure to wait for the delayed rewards), or total trials (sum of reward choice errors, reward wait errors, and acquired rewards). By contrast, during the long (7-11 s) delayed reward condition, the number of wait errors significantly increased while the numbers of total trials and choice errors did not significantly change. These results indicate that the activation of dorsal raphe serotonin neurons is necessary for waiting for long delayed rewards and suggest that elevated serotonin activity facilitates waiting behavior when there is the prospect of forthcoming rewards.

  10. Rapid FPGA-based Delay Estimation for the Hardware/Software Partitioning

    Directory of Open Access Journals (Sweden)

    Xiaoxia Niu

    2013-05-01

    Full Text Available To aid in the hardware/software partitioning of the reconfigurable computing systems, it is necessary to conduct fast and accurate FPGA-based delay estimations before the partitioning. Most previous works predict the delay by adopting a high-level delay estimation based on empirical formulae. In such method, the empirical formulae are often obtained by a regression analysis on the real values reported by the synthesis and place-and-route tools of FPGAs. With alternative properties of tools or different FPGA devices, the empirical formulae need to be re-analyzed and decided. However, it is time-consuming due to inevitably repeated running synthesis and place-and-route tasks, which results in slow estimation and always beyond the tolerance of the estimation time. To address this problem, we present an improved high-level delay-estimation method in this article. We derived theory formulae called increasing formulae for HLL (High Level Language operations from the basic idea of the hardware circuit design. These increasing formulae can be fit for most FPGAs. Combining the proposed formulae, the paper proposes a rapid estimation algorithm also. And the algorithm can obtain hardware delay of different hardware versions, thus reduces the number of times of running the time-consuming tasks greatly. Experimental results show that our method can achieve error within 2.69% for virtex-5 FPGA, compared with the real values.

  11. Zooming in on children's behavior during delay of gratification: Disentangling impulsigenic and volitional processes underlying self-regulation.

    Science.gov (United States)

    Neuenschwander, Regula; Blair, Clancy

    2017-02-01

    When delaying gratification, both motivational and regulatory processes are likely to be at play; however, the relative contributions of motivational and regulatory influences on delay behavior are unclear. By examining behavioral responses during a delay task, this study sought to examine the motivational (anticipatory behavior) and regulatory mechanisms (executive function and self-control strategies) underlying children's self-regulation. The participants, 65 5- to 9-year-old children (Mage=7.19years, SD=0.89), were video-recorded during a delay procedure and later coded for anticipatory behaviors (e.g., gazing intensely at the tablet) and self-control strategies. Children also completed two executive function (EF) tasks. We found that anticipatory behavior was curvilinearly related to delay time. Children showing either very low or very high levels of anticipatory behavior were not able to wait the entire time. Furthermore, our results indicated that anticipatory behavior interacted with EF to predict delay time. Specifically, anticipatory behavior was negatively related to delay time only if EF abilities were low. Finally, self-control strategies also interacted with EF to predict children's ability to delay. Spontaneous engagement in self-control strategies such as fidgeting and engagement in alternative activities were beneficial for children with low EF but were unrelated to delay time for children with high EF. Results indicate the value of examining motivational and regulatory influences on delay behavior. Lapses in self-regulation may be due to the combination of powerful impulsigenic (i.e., anticipatory behavior) and weak volitional processes (i.e., EF, self-control strategies). Copyright © 2016. Published by Elsevier Inc.

  12. Environmental enrichment and working memory tasks decrease hippocampal cell proliferation after wheel running--A role for the prefrontal cortex in hippocampal plasticity?

    Science.gov (United States)

    Schaefers, Andrea T U

    2015-10-22

    Despite an increasing amount of evidence about the regulation of adult hippocampal neurogenesis on the local level, less attention has been paid to its systemic embedding in wider brain circuits. The aim of the present study was to obtain evidence for a potential role of the prefrontal cortex in the regulation of adult hippocampal neurogenesis. We hypothesised that activation of the prefrontal cortex by environmental enrichment or a working-memory task would decrease previously enhanced cell proliferation rates. Wheel running was applied as a common stimulator of cell proliferation in CD1 mice reared under deprivation of natural environmental stimulation. Next, the animals were assigned to four groups for different treatments in the following three days: housing under continued deprivation, environmental enrichment, a spatial-delayed alternation task in an automated T-maze that activates the prefrontal cortex by working-memory requirements or a control task in the automated T-maze differing only in the single parameter working-memory-associated delay. Both the environmental enrichment and spatial-delayed alternation tasks decreased cell proliferation rates in the dentate gyrus compared to deprived housing and the control task in the T-maze. As the control animals underwent the same procedures and stressors and differed only in the single parameter working-memory-associated delay, the working-memory requirement seems to be the crucial factor for decreasing cell proliferation rates. Taken together, these results suggest that the prefrontal cortex may play a role in the regulation of hippocampal cell proliferation.

  13. Exploring Different Types of Academic Delayers: A Latent Profile Analysis

    Science.gov (United States)

    Grunschel, Carola; Patrzek, Justine; Fries, Stefan

    2013-01-01

    In this study, we explored whether there are different types of academic delayers (i.e., types of students who delay academic tasks). Latent profile analysis based on 554 university students' reasons for academic delay revealed four distinct types: inconspicuous, successful pressure-seeking, worried/anxious, and discontent with studies. The types…

  14. The effects of the framing of time on delay discounting.

    Science.gov (United States)

    DeHart, William Brady; Odum, Amy L

    2015-01-01

    We examined the effects of the framing of time on delay discounting. Delay discounting is the process by which delayed outcomes are devalued as a function of time. Time in a titrating delay discounting task is often framed in calendar units (e.g., as 1 week, 1 month, etc.). When time is framed as a specific date, delayed outcomes are discounted less compared to the calendar format. Other forms of framing time; however, have not been explored. All participants completed a titrating calendar unit delay-discounting task for money. Participants were also assigned to one of two delay discounting tasks: time as dates (e.g., June 1st, 2015) or time in units of days (e.g., 5000 days), using the same delay distribution as the calendar delay-discounting task. Time framed as dates resulted in less discounting compared to the calendar method, whereas time framed as days resulted in greater discounting compared to the calendar method. The hyperboloid model fit best compared to the hyperbola and exponential models. How time is framed may alter how participants attend to the delays as well as how the delayed outcome is valued. Altering how time is framed may serve to improve adherence to goals with delayed outcomes.

  15. Creativity, Overinclusion, and Everyday Tasks

    Science.gov (United States)

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

    2014-01-01

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

  16. Facilitating tolerance of delayed reinforcement during functional communication training.

    Science.gov (United States)

    Fisher, W W; Thompson, R H; Hagopian, L P; Bowman, L G; Krug, A

    2000-01-01

    Few clinical investigations have addressed the problem of delayed reinforcement. In this investigation, three individuals whose destructive behavior was maintained by positive reinforcement were treated using functional communication training (FCT) with extinction (EXT). Next, procedures used in the basic literature on delayed reinforcement and self-control (reinforcer delay fading, punishment of impulsive responding, and provision of an alternative activity during reinforcer delay) were used to teach participants to tolerate delayed reinforcement. With the first case, reinforcer delay fading alone was effective at maintaining low rates of destructive behavior while introducing delayed reinforcement. In the second case, the addition of a punishment component reduced destructive behavior to near-zero levels and facilitated reinforcer delay fading. With the third case, reinforcer delay fading was associated with increases in masturbation and head rolling, but prompting and praising the individual for completing work during the delay interval reduced all problem behaviors and facilitated reinforcer delay fading.

  17. Delay-Amount Tradeoffs in Choices by Pigeons and Rats: Hyperbolic versus Exponential Discounting

    Science.gov (United States)

    Mazur, James E.; Biondi, Dawn R.

    2009-01-01

    An adjusting-delay procedure was used to study the choices of pigeons and rats when both delay and amount of reinforcement were varied. In different conditions, the choice alternatives included one versus two reinforcers, one versus three reinforcers, and three versus two reinforcers. The delay to one alternative (the standard alternative) was…

  18. Delayed childbearing.

    Science.gov (United States)

    Francis, H H

    1985-06-01

    In many Western nations, including England and Wales, Sweden, and the US, there is a current trend towards delayed childbearing because of women's pursuit of a career, later marriage, a longer interval between marriage and the 1st birth, and the increasing number of divorcees having children in a 2nd marriage. Wives of men in social classes I and II in England and Wales are, on average, having their 1st child at 27.9 years, 1.6 years later than in 1973, and in social classes IV and V, 1.0 years later than in 1973, at a mean age of 23.7 years. Consequently, the total period fertility rate for British women aged 30-34 years, 35-39 years, and 40 and over increased by 4%, 2%, and 4%, respectively, between 1982-83, in contrast to reductions of 2% and 3%, respectively, in the 15-19 year and 20-24 year age groups, with the 25-29-year-olds remaining static. The average maternal mortality for all parties in England and Wales during 1976-78 was 106/million for adolescents, 70.4/million for 20-24 year-olds, and 1162/million for those aged 40 years and older. The specific obstetric and allied conditions which increase with age are the hypertensive diseases of pregnancy, hemorrhage, pulmonary embolism, abortion, cardiac disease, caesarean section, ruptured uterus, and amniotic fluid embolism. The Swedish Medical Birth Registry of all live births and perinatal deaths since 1973 has shown that the risk of late fetal death is significantly greater in women aged 30-39 years than in those of the same parity and gravidity aged 20-24 years. The risk of giving birth to low birth weight babies preterm and at term and of premature labor are similarly increased. The early neonatal death rate also was increased for primigravidas and nulliparas in the 30-39 year age group but not in parous women. This is, in part, due to the rise in incidence of fetal abnormalities with advancing maternal age because of chromosomal and nonchromosomal anomalies. These also appear to be the cause of the

  19. Improvement in Delay of Information flow in Energy Efficiency Organization

    Directory of Open Access Journals (Sweden)

    Elham Hasanzadeh

    2010-09-01

    Full Text Available One of the most important issues in task organization is service speed and reduction of delays. High speedin tasks and reduction of delay cause high performance in task organization. So many studies have done inthis field. Some of these studies during the past ten years are redesigning tasks in information process,using the simulation product development, designing and manufacturing managing supply chain, and FINCmethodology which has been used in military of American and Australia.In this article FINC methodology is modified for a business organization. The proposed method applied oninformation flows of current situation of Iran energy efficiency organization. Mind manager software isused for viewing it by social network analysis and then FINC methodology for calculation of delay rate onit. Sum of delay rate with delays in decision nodes was added and then improved.

  20. Compact cascadable gm-C all-pass true time delay cell with reduced delay variation over frequency

    NARCIS (Netherlands)

    Garakoui, Seyed Kasra; Klumperink, Eric A.M.; Nauta, Bram; Vliet, van Frank E.

    2015-01-01

    At low-GHz frequencies, analog time-delay cells realized by LC delay lines or transmission lines are unpractical in CMOS, due to their large size. As an alternative, delays can be approximated by all-pass filters exploiting transconductors and capacitors (g m -C filters). This paper presents an easi

  1. Persistent coordination patterns in a complex task after 10 years delay: subtitle: how validate the old saying "once you have learned how to ride a bicycle, you never forget!".

    Science.gov (United States)

    Nourrit-Lucas, Déborah; Zelic, Grégory; Deschamps, Thibault; Hilpron, Michael; Delignières, Didier

    2013-12-01

    Motor learning studies have for a long time focused on performance variables (in terms of speed or accuracy) in assessing learning, transfer and retention of motor skills. We argue, however, that learning essentially resides in changes in coordination variables (in terms of qualitative organization of behavior) and that relevant tests for assessing the effectiveness of learning and retention should consider these variables. The aim of this experiment was to test the retention of a complex motor skill, after a long-term delay. Ten years ago, five participants were involved in an experiment during which they practiced for 39 sessions of ten 1-min trials on a ski-simulator. All participants volunteered for a retention test, ten years after, for one session of ten 1-min trials. Analyses focused on the oscillations of the platform of the simulator. Performance was assessed in terms of amplitude and frequency. Coordination was accounted for by an analysis of dynamical properties of the motion of the platform, and especially the nature of the damping function that was exploited for sustaining the limit cycle dynamics. Results showed a significant decrement in performance variables. In contrast, all participants adopted from the first trial onwards the coordination mode they learned 10years ago. These results confirm the strong persistence of coordination modes, once acquired and stabilized in the behavioral repertoire. They also support the importance of coordination variables for a valid assessment of learning and retention.

  2. Alternative energies; Energies alternatives

    Energy Technology Data Exchange (ETDEWEB)

    Bonal, J.; Rossetti, P

    2007-07-01

    The earth took millions years to made the petroleum, the gas the coal and the uranium. Only a few centuries will be needed to exhaust these fossil fuels and some years to reach expensive prices. Will the wold continue on this way of energy compulsive consumption? The renewable energies and some citizen attitudes are sufficient to break this spiral. This book proposes to discuss these alternative energies. It shows that this attitude must be supported by the government. It takes stock on the more recent information concerning the renewable energies. it develops three main points: the electricity storage, the housing and the transports. (A.L.B.)

  3. Validity of False Belief Tasks in Blind Children

    Science.gov (United States)

    Brambring, Michael; Asbrock, Doreen

    2010-01-01

    Previous studies have reported that congenitally blind children without any additional impairment reveal a developmental delay of at least 4 years in perspective taking based on testing first-order false-belief tasks. These authors interpret this delay as a sign of autism-like behavior. However, the delay may be caused by testing blind children…

  4. Alternative additives; Alternative additiver

    Energy Technology Data Exchange (ETDEWEB)

    2007-08-15

    In this project a number of industrial and agricultural waste products have been characterised and evaluated in terms of alkali-getter performance. The intended use is for biomass-fired power stations aiming at reducing corrosion or slagging related problems. The following products have been obtained, characterised and evaluated: 1) Brewery draff 2) Danish de-gassed manure 3) Paper sludge 4) Moulding sand 5) Spent bleaching earth 6) Anorthosite 7) Sand 8) Clay-sludge. Most of the above alternative additive candidates are deemed unsuitable due to insufficient chemical effect and/or expensive requirements for pre-treatment (such as drying and transportation). 3 products were selected for full-scale testing: de-gassed manure, spent bleaching earth and clay slugde. The full scale tests were undertaken at the biomass-fired power stations in Koege, Slagelse and Ensted. Spent bleaching earth (SBE) and clay sludge were the only tested additive candidates that had a proven ability to react with KCl, to thereby reduce Cl-concentrations in deposits, and reduce the deposit flux to superheater tubes. Their performance was shown to nearly as good as commercial additives. De-gassed manure, however, did not evaluate positively due to inhibiting effects of Ca in the manure. Furthermore, de-gassed manure has a high concentration of heavy metals, which imposes a financial burden with regard to proper disposal of the ash by-products. Clay-sludge is a wet clay slurring, and drying and transportation of this product entails substantial costs. Spent bleaching does not require much pre-treatment and is therefore the most promising alternative additive. On the other hand, bleaching earth contains residual plant oil which means that a range of legislation relating to waste combustion comes into play. Not least a waste combustion fee of 330 DKK/tonne. For all alternative (and commercial) additives disposal costs of the increase ash by-products represents a significant cost. This is

  5. When good pigeons make bad decisions: Choice with probabilistic delays and outcomes.

    Science.gov (United States)

    Pisklak, Jeffrey M; McDevitt, Margaret A; Dunn, Roger M; Spetch, Marcia L

    2015-11-01

    Pigeons chose between an (optimal) alternative that sometimes provided food after a 10-s delay and other times after a 40-s delay and another (suboptimal) alternative that sometimes provided food after 10 s but other times no food after 40 s. When outcomes were not signaled during the delays, pigeons strongly preferred the optimal alternative. When outcomes were signaled, choices of the suboptimal alternative increased and most pigeons preferred the alternative that provided no food after the long delay despite the cost in terms of obtained food. The pattern of results was similar whether the short delays occurred on 25% or 50% of the trials. Shortening the 40-s delay to food sharply reduced suboptimal choices, but shortening the delay to no food had little effect. The results suggest that a signaled delay to no food does not punish responding in probabilistic choice procedures. The findings are discussed in terms of conditioned reinforcement by signals for good news.

  6. Load sharing in models with communication delays

    NARCIS (Netherlands)

    Geest, R.A.B. van der

    1994-01-01

    Computer systems may be connected in a network to share workload. A control problem then is to decide which computer should carry out which task. Novel in this report is a model for load sharing with communication delays. It takes nonnegligible time for information from one computer to reach the oth

  7. The Right Delay

    NARCIS (Netherlands)

    Datadien, A.H.R.; Haselager, W.F.G.; Sprinkhuizen-Kuyper, I.G.

    2011-01-01

    Axonal conduction delays should not be ignored in simulations of spiking neural networks. Here it is shown that by using axonal conduction delays, neurons can display sensitivity to a specific spatio-temporal spike pattern. By using delays that complement the firing times in a pattern, spikes can ar

  8. 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.

  9. Internet Addiction and Delay Discounting in College Students

    Science.gov (United States)

    Saville, Bryan K.; Gisbert, Amanda; Kopp, Jason; Telesco, Carolyn

    2010-01-01

    To examine the relation between Internet addiction and delay discounting, we gave 276 college students a survey designed to measure Internet addiction and a paper-based delay-discounting task. In our larger sample, we identified 14 students who met the criteria for Internet addiction; we also identified 14 matched controls who were similar to the…

  10. Internet Addiction and Delay Discounting in College Students

    Science.gov (United States)

    Saville, Bryan K.; Gisbert, Amanda; Kopp, Jason; Telesco, Carolyn

    2010-01-01

    To examine the relation between Internet addiction and delay discounting, we gave 276 college students a survey designed to measure Internet addiction and a paper-based delay-discounting task. In our larger sample, we identified 14 students who met the criteria for Internet addiction; we also identified 14 matched controls who were similar to the…

  11. Alternative Medicine

    Science.gov (United States)

    ... Involved News About Us Donate In This Section Alternative Medicine en Español email Send this article to a ... Dr. Yvonne Ou on Lifestyle Modifications and Glaucoma Alternative medicine may be defined as non-standard, unconventional treatments ...

  12. An Analytical Delay Model

    Institute of Scientific and Technical Information of China (English)

    MIN Yinghua; LI Zhongcheng

    1999-01-01

    Delay consideration has been a majorissue in design and test of high performance digital circuits. Theassumption of input signal change occurring only when all internal nodesare stable restricts the increase of clock frequency. It is no longertrue for wave pipelining circuits. However, previous logical delaymodels are based on the assumption. In addition, the stable time of arobust delay test generally depends on the longest sensitizable pathdelay. Thus, a new delay model is desirable. This paper explores thenecessity first. Then, Boolean process to analytically describe thelogical and timing behavior of a digital circuit is reviewed. Theconcept of sensitization is redefined precisely in this paper. Based onthe new concept of sensitization, an analytical delay model isintroduced. As a result, many untestable delay faults under thelogical delay model can be tested if the output waveforms can be sampledat more time points. The longest sensitizable path length is computedfor circuit design and delay test.

  13. Measuring and Modelling Delays in Robot Manipulators for Temporally Precise Control using Machine Learning.

    OpenAIRE

    Andersen, Thomas Timm; Amor, Heni Ben; Andersen, Nils Axel; Ravn, Ole

    2015-01-01

    Latencies and delays play an important role in temporally precise robot control. During dynamic tasks in particular, a robot has to account for inherent delays to reach manipulated objects in time. The different types of occurring delays are typically convoluted and thereby hard to measure and separate. In this paper, we present a data-driven methodology for separating and modelling inherent delays during robot control. We show how both actuation and response delays can be modelled using mode...

  14. Delay Banking for Managing Air Traffic

    Science.gov (United States)

    Green, Steve

    2008-01-01

    flight that has accepted, or upon which was imposed, a flow restriction. The amount of the credit would increase with the amount of delay caused by the flow restriction, the exact amount depending on which of several candidate formulas is eventually chosen. For example, according to one formula, there would be no credit for a delay smaller than some threshold value (e.g., 30 seconds) and the amount of the credit for a longer delay would be set at the amount of the delay minus the threshold value. Optionally, the value of a delay credit could be made to decay with time according to a suitable formula (e.g., an exponential decay). Also, optionally, a transaction charge could be assessed against the value of a delay credit that an operator used on a flight different from the one for which the delay originated or that was traded with a different operator. The delay credits accumulated by a given airline could be utilized in various ways. For example, an operator could enter a bid for priority handling in a new flow restriction that impacts one or more of the operator s flights; if the bid were unsuccessful, all or a portion of the credit would be returned to the bidder. If the bid pertained to a single aircraft that was in a queue, delay credits could be consumed in moving the aircraft to an earlier position within the queue. In the case of a flow restriction involving a choice of alternate routes, planned altitude profile, aircraft spacing, or other non-queue flow restrictions, delay credits could be used to bid for an alternative assignment.

  15. Self-control assessments of capuchin monkeys with the rotating tray task and the accumulation task.

    Science.gov (United States)

    Beran, Michael J; Perdue, Bonnie M; Rossettie, Mattea S; James, Brielle T; Whitham, Will; Walker, Bradlyn; Futch, Sara E; Parrish, Audrey E

    2016-08-01

    Recent studies of delay of gratification in capuchin monkeys using a rotating tray (RT) task have shown improved self-control performance in these animals in comparison to the accumulation (AC) task. In this study, we investigated whether this improvement resulted from the difference in methods between the rotating tray task and previous tests, or whether it was the result of greater overall experience with delay of gratification tasks. Experiment 1 produced similar performance levels by capuchins monkeys in the RT and AC tasks when identical reward and temporal parameters were used. Experiment 2 demonstrated a similar result using reward amounts that were more similar to previous AC experiments with these monkeys. In Experiment 3, monkeys performed multiple versions of the AC task with varied reward and temporal parameters. Their self-control behavior was found to be dependent on the overall delay to reward consumption, rather than the overall reward amount ultimately consumed. These findings indicate that these capuchin monkeys' self-control capacities were more likely to have improved across studies because of the greater experience they had with delay of gratification tasks. Experiment 4 and Experiment 5 tested new, task-naïve monkeys on both tasks, finding more limited evidence of self-control, and no evidence that one task was more beneficial than the other in promoting self-control. The results of this study suggest that future testing of this kind should focus on temporal parameters and reward magnitude parameters to establish accurate measures of delay of gratification capacity and development in this species and perhaps others.

  16. Decision paths in complex tasks

    Science.gov (United States)

    Galanter, Eugene

    1991-01-01

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

  17. Mental fatigue and task control : Planning and preparation

    NARCIS (Netherlands)

    Lorist, MM; Klein, M; Nieuwenhuis, S; De Jong, R; Mulder, G; Meijman, TF

    2000-01-01

    The effects of mental fatigue on planning and preparation for future actions were examined, using a task switching paradigm. Fatigue was induced by "time on task," with subjects performing a switch task continuously for 2 hr. Subjects had to alternate between tasks on every second trial, so that a n

  18. Understanding the Delayed-Keyword Effect on Metacomprehension Accuracy

    Science.gov (United States)

    Thiede, Keith W.; Dunlosky, John; Griffin, Thomas D.; Wiley, Jennifer

    2005-01-01

    The typical finding from research on metacomprehension is that accuracy is quite low. However, recent studies have shown robust accuracy improvements when judgments follow certain generation tasks (summarizing or keyword listing) but only when these tasks are performed at a delay rather than immediately after reading (K. W. Thiede & M. C. M.…

  19. RELATIONSHIP BETWEEN THE TASK AVERSIVENESS AND ACADEMIC PROCRASTINATION

    Directory of Open Access Journals (Sweden)

    Magvirasari Lestari Linra

    2016-12-01

    Full Text Available Academic procrastination occurs when certain tasks are considered unpleasant, an unpleasant task and the usual delayed them is the task of writing, reading, studying for the exam, meetings, and administrative. The purpose of this study was to determine the relationship of the task aversiveness with academic procrastination. Subject of the study were 100 students out of a population of 516 students of the Faculty of Psychology class of 2012-2014. The method used in this research is quantitative by using Spearman rho as data analysis techniques. The research instrument consists of academic procrastination scale and the scale of the task aversiveness. Based on the results of correlation is known that there is a positive relationship between task aversiveness with academic procrastination with a correlation coefficient r = 0.508; p = 0.000. The results showed that of the 100 students of the Faculty of Psychology University of Makassar has a degree of relationship between task aversiveness with academic procrastination is on the very low category (25, 8%. Area / types of tasks delayed is not necessarily an unpleasant task and otherwise unpleasant task may not be postponed. Area task the highest level of aversive and delays are areas the task of writing and reading. This study illustrates that academic procrastination can be lowered by a change in the mindset of an unpleasant task.

  20. The neurodynamics underlying attentional control in set shifting tasks.

    Science.gov (United States)

    Stemme, Anja; Deco, Gustavo; Busch, Astrid

    2007-09-01

    In this work we address key phenomena observed with classical set shifting tasks as the "Wisconsin Card Sorting Test" or the "Stroop" task: Different types of errors and increased response times reflecting decreased attention. A component of major importance in these tasks is referred to as the "attentional control" thought to be implemented by the prefrontal cortex which acts primarily by an amplification of task relevant information. This mode of operation is illustrated by a neurodynamical model developed for a new kind of set shifting experiment: The Wisconsin-Delayed-Match-to-Sample task combines uninstructed shifts as investigated in Wisconsin-like tasks with a Delayed-Match-to-Sample paradigm. These newly developed WDMS experiments in conjunction with the neurodynamical simulations are able to explain the reason for decreased attention in set shifting experiments as well the different consequences of decreased attention in tasks requiring bivalent yes/no responses compared to tasks requiring multivalent responses.

  1. A Job with a Future? Delay Discounting, Magnitude Effects, and Domain Independence of Utility for Career Decisions.

    Science.gov (United States)

    Schoenfelder, Thomas E.; Hantula, Donald A.

    2003-01-01

    Seniors (n=20) assessed two job offers with differences in domain (salary/tasks), delay (career-long earnings), and magnitude (initial salary offer). Contrary to discounted utility theory, choices reflected nonconstant discount rates for future salary/tasks (delay effect), lower discount rates for salary/preferred tasks (magnitude effect), and a…

  2. Delayed emergence after anesthesia.

    Science.gov (United States)

    Tzabazis, Alexander; Miller, Christopher; Dobrow, Marc F; Zheng, Karl; Brock-Utne, John G

    2015-06-01

    In most instances, delayed emergence from anesthesia is attributed to residual anesthetic or analgesic medications. However, delayed emergence can be secondary to unusual causes and present diagnostic dilemmas. Data from clinical studies is scarce and most available published material is comprised of case reports. In this review, we summarize and discuss less common and difficult to diagnose reasons for delayed emergence and present cases from our own experience or reference published case reports/case series. The goal is to draw attention to less common reasons for delayed emergence, identify patient populations that are potentially at risk and to help anesthesiologists identifying a possible cause why their patient is slow to wake up.

  3. Hippocampus Is Required for Paired Associate Memory with Neither Delay Nor Trial Uniqueness

    Science.gov (United States)

    Yoon, Jinah; Seo, Yeran; Kim, Jangjin; Lee, Inah

    2012-01-01

    Cued retrieval of memory is typically examined with delay when testing hippocampal functions, as in delayed matching-to-sample tasks. Equally emphasized in the literature, on the other hand, is the hippocampal involvement in making arbitrary associations. Paired associate memory tasks are widely used for examining this function. However, the two…

  4. The Effects of Inflation and Interest Rates on Delay Discounting in Human Behavior

    Science.gov (United States)

    Kawashima, Kentaro

    2006-01-01

    Interest and inflation rates may be major determinants of delay discounting, but these variables have not been controlled in past experiments because they depend on macroeconomic conditions. This study uses a computer game-like task to investigate the effects of inflation rates on people's subjective valuation of delayed rewards. During the task,…

  5. Visual discrimination of delayed self-generated movement reveals the temporal limit of proprioceptive-visual intermodal integration.

    Science.gov (United States)

    Jaime, Mark; O'Driscoll, Kelly; Moore, Chris

    2016-07-01

    This study examined the intermodal integration of visual-proprioceptive feedback via a novel visual discrimination task of delayed self-generated movement. Participants performed a goal-oriented task in which visual feedback was available only via delayed videos displayed on two monitors-each with different delay durations. During task performance, delay duration was varied for one of the videos in the pair relative to a standard delay, which was held constant. Participants were required to identify and use the video with the lesser delay to perform the task. Visual discrimination of the lesser-delayed video was examined under four conditions in which the standard delay was increased for each condition. A temporal limit for proprioceptive-visual intermodal integration of 3-5s was revealed by subjects' inability to reliably discriminate video pairs.

  6. A change of task prolongs early processes: evidence from ERPs in lexical tasks.

    Science.gov (United States)

    Elchlepp, Heike; Lavric, Aureliu; Monsell, Stephen

    2015-04-01

    Switching tasks costs time. Allowing time to prepare reduces the cost, but usually leaves an irreducible "residual cost." Most accounts of this residual cost locate it within the response-selection stage of processing. To determine which processing stage is affected, we measured event-related potentials (ERPs) as participants performed a reading task or a perceptual judgment task, and examined the effect of a task switch on early markers of lexical processing. A task cue preceding a string of blue and red letters instructed the participant either to read the letter string (for a semantic classification in Experiment 1, and a lexical decision in Experiment 2) or to judge the symmetry of its color pattern. In Experiment 1, having to switch to the reading task delayed the evolution of the effect of word frequency on the reading task ERP by a substantial fraction of the effect on reaction time (RT). In Experiment 2, a task switch delayed the onset of the effect of lexical status on the ERP by about the same extent that it prolonged the RT. These effects indicate an early locus of (most of) the residual switch cost: We propose that this reflects a form of task-related attentional inertia. Other findings have implications for the automaticity of lexical access: Effects of frequency, lexicality, and orthographic familiarity on ERPs in the symmetry task indicated involuntary, but attenuated, orthographic and lexical processing even when attention was focused on a nonlexical property.

  7. American Dream Delayed

    DEFF Research Database (Denmark)

    Khorunzhina, Natalia; Miller, Robert A.

    This paper investigates the delay in homeownership and a subsequent reduction in homeownership rate observed over the past decades. We focus on the delay in giving birth to children and increased labor market participation as contributing factors to homeownership dynamics for prime-age female hou...

  8. Alternative wastewatersystems

    DEFF Research Database (Denmark)

    Dyck-Madsen, Søren; Hoffmann, Birgitte; Gabriel, Søren

    1999-01-01

    The report:-  Communicates experiences from Swedish buildings from the establishment and running of alternative wastewater systems. Communicates pictures of alternative buildings and wastewater systems in Sweden. Gives a short evaluation of the performance and the sustainability of the systems....

  9. Development of a statistically based access delay timeline methodology.

    Energy Technology Data Exchange (ETDEWEB)

    Rivera, W. Gary; Robinson, David Gerald; Wyss, Gregory Dane; Hendrickson, Stacey M. Langfitt

    2013-02-01

    The charter for adversarial delay is to hinder access to critical resources through the use of physical systems increasing an adversarys task time. The traditional method for characterizing access delay has been a simple model focused on accumulating times required to complete each task with little regard to uncertainty, complexity, or decreased efficiency associated with multiple sequential tasks or stress. The delay associated with any given barrier or path is further discounted to worst-case, and often unrealistic, times based on a high-level adversary, resulting in a highly conservative calculation of total delay. This leads to delay systems that require significant funding and personnel resources in order to defend against the assumed threat, which for many sites and applications becomes cost prohibitive. A new methodology has been developed that considers the uncertainties inherent in the problem to develop a realistic timeline distribution for a given adversary path. This new methodology incorporates advanced Bayesian statistical theory and methodologies, taking into account small sample size, expert judgment, human factors and threat uncertainty. The result is an algorithm that can calculate a probability distribution function of delay times directly related to system risk. Through further analysis, the access delay analyst or end user can use the results in making informed decisions while weighing benefits against risks, ultimately resulting in greater system effectiveness with lower cost.

  10. Alternative metrics

    Science.gov (United States)

    2012-11-01

    As the old 'publish or perish' adage is brought into question, additional research-impact indices, known as altmetrics, are offering new evaluation alternatives. But such metrics may need to adjust to the evolution of science publishing.

  11. Contract delay: what is it and how are we performing?

    Directory of Open Access Journals (Sweden)

    David Finnie

    2012-02-01

    Full Text Available AbstractThis paper examines the management of contract delays in the construction industry as currently practised, and suggests some best practice alternative methods.Research results about the level of contractor’s time management skills were analysed to determine the related impact on their ability to manage contract delays. A comparison was made between three conditions of contracts used in New Zealand to determine how delay management should be managed with a discussion about how the different contract conditions distribute risk among the parties. Recommendations were made to improve contract conditions, up-skill industry practitioners and ensure student graduates have adequate delay management skills.

  12. commensurate point delays

    Directory of Open Access Journals (Sweden)

    M. de la Sen

    2005-01-01

    nominal controller is maintained. In the current approach, the finite spectrum assignment is only considered as a particular case of the designer's choice of a (delay-dependent arbitrary spectrum assignment objective.

  13. Final report, Task 3: possible uses of the Nuclear Fuel Services, Inc. reprocessing plant at West Valley, New York. [For research on alternative fuel cycles, spiking, coprocessing, waste solidification, and recovery of radioactive gases

    Energy Technology Data Exchange (ETDEWEB)

    None

    1978-06-14

    The West Valley Plant could readily be used for work on reprocessing of alternative fuels, spiking, coprocessing (including CIVEX), waste solidification, and the recovery of radioactive gases. The plant could be easily modified for any scale between small-scale experimental work to production-scale demonstration, involving virtually any combination of fissile/fertile fuel materials that might be used in the future. The use of this plant for the contemplated experimental work would involve lower capital costs than the use of other facilities at DOE sites, except possibly for spiking of recovered products; the operating costs would be no greater than at other sites. The work on reprocessing of alternative fuels and coprocessing could commence within about one year; on recovery of radioactive gases, in 3 to 5 years; on spiking, in 4 years; and on waste solidification demonstration, in about 5 years. The contemplated work could be begun at this plant at least as early as at Barnwell, although work on spiking of recovered products could probably be started in existing hot cells earlier than at West Valley. (DLC)

  14. Time Delay Cosmography

    OpenAIRE

    Treu, Tommaso; Marshall, Philip J.

    2016-01-01

    Gravitational time delays, observed in strong lens systems where the variable background source is multiply-imaged by a massive galaxy in the foreground, provide direct measurements of cosmological distance that are very complementary to other cosmographic probes. The success of the technique depends on the availability and size of a suitable sample of lensed quasars or supernovae, precise measurements of the time delays, accurate modeling of the gravitational potential of the main deflector,...

  15. Time delay measurement in the frequency domain

    Energy Technology Data Exchange (ETDEWEB)

    Durbin, Stephen M., E-mail: durbin@purdue.edu; Liu, Shih-Chieh [Purdue University, West Lafayette, IN 47907 (United States); Dufresne, Eric M.; Li, Yuelin; Wen, Haidan [Argonne National Laboratory, Argonne, IL 60439 (United States)

    2015-08-06

    A simple frequency domain technique for determining the time delay between laser pump and X-ray probe pulses achieves 1 ps resolution even for ∼100 ps synchrotron pulses, permitting improved pump–probe characterization of ultrafast processes. Pump–probe studies at synchrotrons using X-ray and laser pulses require accurate determination of the time delay between pulses. This becomes especially important when observing ultrafast responses with lifetimes approaching or even less than the X-ray pulse duration (∼100 ps). The standard approach of inspecting the time response of a detector sensitive to both types of pulses can have limitations due to dissimilar pulse profiles and other experimental factors. Here, a simple alternative is presented, where the frequency response of the detector is monitored versus time delay. Measurements readily demonstrate a time resolution of ∼1 ps. Improved precision is possible by simply extending the data acquisition time.

  16. Effect of Small Transmission Delay on Human Behavior in Audio Communication

    Science.gov (United States)

    Ohnishi, Hitoshi; Mochizuki, Kaname

    Transmission delay in audio communications is a well-known obstacle to achieving smooth communication. However, it is not known what kinds of effects are caused by small delays. We hypothesized that the small delay in the listener's responses disturbs the speaker's “verbal conditioning, ” where the verbal behavior of the speaker varies in accordance with the listener's responses. We examined whether the small delays in the listener's responses disturb the speaker's verbal conditioning using an artificial-grammar learning task. The results suggested that a 300-ms delay disturbed the participants' verbal conditioning although they were not adequately aware of the delay.

  17. Delay Efficient Method for Delivering IPTV Services

    Directory of Open Access Journals (Sweden)

    Sangamesh

    2014-07-01

    Full Text Available Internet Protocol Television (IPTV is a system through which Internet television services are delivered using the architecture and networking methods of the Internet Protocol Suite over a packet-switched network infrastructure, e.g., the Internet and broadband Internet access networks, instead of being delivered through traditional radio frequency broadcast, satellite signal, and cable television (CATV formats. IPTV provides mainly three services: live TV, catch up TV, and video on demand (VoD.This paper focuses on delivering the live TV services by exploiting the virtualised cloud architecture of the IPTV and statistical multiplexing. The VoD tasks are prescheduled so that there will be less Instant Channel Change (ICC delay. We select a proper scheduling algorithm for rescheduling the VoD tasks. We then implement the scheduling algorithm for preshifting the VoD tasks.

  18. Workspace visualization and time-delay telerobotic operations

    Science.gov (United States)

    Schenker, P. S.; Bejczy, A. K.

    1990-01-01

    The paper examines the performance of telerobotic tasks where the operator and robot are physically separated, and a comunication time delay of up to several seconds between them exists. This situation is applicable to space robotic servicing-assembly-maintenance operations on low earth or geosynchronous orbits with a ground-based command station. Attention is given to two developments which address advanced time-delay teleoperations for unstructured tasks: (1) the 'phantom robot', a real-time predictive graphics simulator developed to allow teleoperator eye-to-hand coordination or robot free-space kinematics under a time delay of several seconds; and (2) shared compliance control, a modified form of automatic electromechanical impedance control employed in parallel with manual position control to permit soft contact and grasp compliance with workpiece geometry under a time delay of several seconds.

  19. Efficient Training of Recurrent Neural Network with Time Delays.

    Science.gov (United States)

    Marom, Emanuel; Saad, David; Cohen, Barak

    1997-01-01

    Training recurrent neural networks to perform certain tasks is known to be difficult. The possibility of adding synaptic delays to the network properties makes the training task more difficult. However, the disadvantage of tough training procedure is diminished by the improved network performance. During our research of training neural networks with time delays we encountered a robust method for accomplishing the training task. The method is based on adaptive simulated annealing algorithm (ASA) which was found to be superior to other training algorithms. It requires no tuning and is fast enough to enable training to be held on low end platforms such as personal computers. The implementation of the algorithm is presented over a set of typical benchmark tests of training recurrent neural networks with time delays. Copyright 1996 Elsevier Science Ltd.

  20. Inverse Problems for Nonlinear Delay Systems

    Science.gov (United States)

    2011-03-15

    Ba82]. For nonlinear delay systems such as those discussed here, approximation in the context of a linear semigroup framework as presented [BBu1, BBu2...linear part generates a linear semigroup as in [BBu1, BBu2, BKap]. One then uses the linear semigroup in a vari- ation of parameters implicit...BBu2, BKap] (for the linear semigroup ) plus a Gronwall inequality. An alternative (and more general) approach given in [Ba82] eschews use of the Trotter

  1. Adaptive Task-Space Cooperative Tracking Control of Networked Robotic Manipulators Without Task-Space Velocity Measurements.

    Science.gov (United States)

    Liang, Xinwu; Wang, Hesheng; Liu, Yun-Hui; Chen, Weidong; Hu, Guoqiang; Zhao, Jie

    2016-10-01

    In this paper, the task-space cooperative tracking control problem of networked robotic manipulators without task-space velocity measurements is addressed. To overcome the problem without task-space velocity measurements, a novel task-space position observer is designed to update the estimated task-space position and to simultaneously provide the estimated task-space velocity, based on which an adaptive cooperative tracking controller without task-space velocity measurements is presented by introducing new estimated task-space reference velocity and acceleration. Furthermore, adaptive laws are provided to cope with uncertain kinematics and dynamics and rigorous stability analysis is given to show asymptotical convergence of the task-space tracking and synchronization errors in the presence of communication delays under strongly connected directed graphs. Simulation results are given to demonstrate the performance of the proposed approach.

  2. Discrimination Acquisition in Children with Developmental Disabilities under Immediate and Delayed Reinforcement

    Science.gov (United States)

    Sy, Jolene R.; Vollmer, Timothy R.

    2012-01-01

    We evaluated the discrimination acquisition of individuals with developmental disabilities under immediate and delayed reinforcement. In Experiment 1, discrimination between two alternatives was examined when reinforcement was immediate or delayed by 20 s, 30 s, or 40 s. In Experiment 2, discrimination between 2 alternatives was compared across an…

  3. Discrimination Acquisition in Children with Developmental Disabilities under Immediate and Delayed Reinforcement

    Science.gov (United States)

    Sy, Jolene R.; Vollmer, Timothy R.

    2012-01-01

    We evaluated the discrimination acquisition of individuals with developmental disabilities under immediate and delayed reinforcement. In Experiment 1, discrimination between two alternatives was examined when reinforcement was immediate or delayed by 20 s, 30 s, or 40 s. In Experiment 2, discrimination between 2 alternatives was compared across an…

  4. OPPORTUNITY COSTS OF REWARD DELAYS AND THE DISCOUNTING OF HYPOTHETICAL MONEY AND CIGARETTES

    Science.gov (United States)

    Johnson, Patrick S.; Herrmann, Evan S.; Johnson, Matthew W.

    2015-01-01

    Humans are reported to discount delayed rewards at lower rates than nonhumans. However, nonhumans are studied in tasks that restrict reinforcement during delays, whereas humans are typically studied in tasks that do not restrict reinforcement during delays. In nonhuman tasks, the opportunity cost of restricted reinforcement during delays may increase delay discounting rates. The present within-subjects study used online crowdsourcing (Amazon Mechanical Turk, or MTurk) to assess the discounting of hypothetical delayed money (and cigarettes in smokers) under four hypothetical framing conditions differing in the availability of reinforcement during delays. At one extreme, participants were free to leave their computer without returning, and engage in any behavior during reward delays (modeling typical human tasks). At the opposite extreme, participants were required to stay at their computer and engage in little other behavior during reward delays (modeling typical nonhuman tasks). Discounting rates increased as an orderly function of opportunity cost. Results also indicated predominantly hyperbolic discounting, the “magnitude effect,” steeper discounting of cigarettes than money, and positive correlations between discounting rates of these commodities. This is the first study to test the effects of opportunity costs on discounting, and suggests that procedural differences may partially account for observed species differences in discounting. PMID:25388973

  5. A task control theory of mirror-touch synesthesia.

    Science.gov (United States)

    Heyes, Cecilia; Catmur, Caroline

    2015-01-01

    Ward and Banissy's illuminating discussion of mirror-touch synesthesia (MTS) encourages research testing two alternatives to Threshold Theory: Their own Self-Other Theory, and "Task Control Theory". MTS may be due to abnormal mirror activity plus a domain-general, rather than a specifically social, impairment in the ability to privilege processing of task-relevant over task-irrelevant information.

  6. Aging and Concurrent Task Performance: Cognitive Demand and Motor Control

    Science.gov (United States)

    Albinet, Cedric; Tomporowski, Phillip D.; Beasman, Kathryn

    2006-01-01

    A motor task that requires fine control of upper limb movements and a cognitive task that requires executive processing--first performing them separately and then concurrently--was performed by 18 young and 18 older adults. The motor task required participants to tap alternatively on two targets, the sizes of which varied systematically. The…

  7. Alternative Veier

    DEFF Research Database (Denmark)

    Kruse, Tove Elisabeth; Salamonsen, Anita

    reflektioner omkring patienters brug af og erfaringer med alternativ behandling. Patientorganisationer, organisatoner for alternative behandlere og organisationer for læger og medicinstuderende har læst bogens patienthistorier og deres perspektiver lægges frem. Til slut i bogen diskuteres betydningen af de...

  8. Growing Alternatives

    DEFF Research Database (Denmark)

    Bagger-Petersen, Mai Corlin

    2014-01-01

    From 2014, Anhui Province will pilot a reform of the residential land market in China, thus integrating rural Anhui in the national housing market. In contrast, artist and activist Ou Ning has proposed the Bishan time money currency, intending to establish an alternative economic circuit in Bishan...

  9. Magnetostrictive Alternator

    Science.gov (United States)

    Dyson, Rodger; Bruder, Geoffrey

    2013-01-01

    This innovation replaces the linear alternator presently used in Stirling engines with a continuous-gradient, impedance-matched, oscillating magnetostrictive transducer that eliminates all moving parts via compression, maintains high efficiency, costs less to manufacture, reduces mass, and eliminates the need for a bearing system. The key components of this new technology are the use of stacked magnetostrictive materials, such as Terfenol-D, under a biased magnetic and stress-induced compression, continuous-gradient impedance-matching material, coils, force-focusing metallic structure, and supports. The acoustic energy from the engine travels through an impedancematching layer that is physically connected to the magnetostrictive mass. Compression bolts keep the structure under compressive strain, allowing for the micron-scale compression of the magnetostrictive material and eliminating the need for bearings. The relatively large millimeter displacement of the pressure side of the impedance-matching material is reduced to micron motion, and undergoes stress amplification at the magnetostrictive interface. The alternating compression and expansion of the magnetostrictive material creates an alternating magnetic field that then induces an electric current in a coil that is wound around the stack. This produces electrical power from the acoustic pressure wave and, if the resonant frequency is tuned to match the engine, can replace the linear alternator that is commonly used.

  10. Alternative Treatments

    Science.gov (United States)

    ... triglyceride (fat) produced by processing coconut oil or palm kernel oil. The body breaks down caprylic acid into substances called “ketone bodies.” The theory behind Axona is that the ketone bodies derived from caprylic acid may provide an alternative energy source for brain cells that have lost ...

  11. Delay differential analysis of time series.

    Science.gov (United States)

    Lainscsek, Claudia; Sejnowski, Terrence J

    2015-03-01

    Nonlinear dynamical system analysis based on embedding theory has been used for modeling and prediction, but it also has applications to signal detection and classification of time series. An embedding creates a multidimensional geometrical object from a single time series. Traditionally either delay or derivative embeddings have been used. The delay embedding is composed of delayed versions of the signal, and the derivative embedding is composed of successive derivatives of the signal. The delay embedding has been extended to nonuniform embeddings to take multiple timescales into account. Both embeddings provide information on the underlying dynamical system without having direct access to all the system variables. Delay differential analysis is based on functional embeddings, a combination of the derivative embedding with nonuniform delay embeddings. Small delay differential equation (DDE) models that best represent relevant dynamic features of time series data are selected from a pool of candidate models for detection or classification. We show that the properties of DDEs support spectral analysis in the time domain where nonlinear correlation functions are used to detect frequencies, frequency and phase couplings, and bispectra. These can be efficiently computed with short time windows and are robust to noise. For frequency analysis, this framework is a multivariate extension of discrete Fourier transform (DFT), and for higher-order spectra, it is a linear and multivariate alternative to multidimensional fast Fourier transform of multidimensional correlations. This method can be applied to short or sparse time series and can be extended to cross-trial and cross-channel spectra if multiple short data segments of the same experiment are available. Together, this time-domain toolbox provides higher temporal resolution, increased frequency and phase coupling information, and it allows an easy and straightforward implementation of higher-order spectra across time

  12. Delay Differential Analysis of Time Series

    Science.gov (United States)

    Lainscsek, Claudia; Sejnowski, Terrence J.

    2015-01-01

    Nonlinear dynamical system analysis based on embedding theory has been used for modeling and prediction, but it also has applications to signal detection and classification of time series. An embedding creates a multidimensional geometrical object from a single time series. Traditionally either delay or derivative embeddings have been used. The delay embedding is composed of delayed versions of the signal, and the derivative embedding is composed of successive derivatives of the signal. The delay embedding has been extended to nonuniform embeddings to take multiple timescales into account. Both embeddings provide information on the underlying dynamical system without having direct access to all the system variables. Delay differential analysis is based on functional embeddings, a combination of the derivative embedding with nonuniform delay embeddings. Small delay differential equation (DDE) models that best represent relevant dynamic features of time series data are selected from a pool of candidate models for detection or classification. We show that the properties of DDEs support spectral analysis in the time domain where nonlinear correlation functions are used to detect frequencies, frequency and phase couplings, and bispectra. These can be efficiently computed with short time windows and are robust to noise. For frequency analysis, this framework is a multivariate extension of discrete Fourier transform (DFT), and for higher-order spectra, it is a linear and multivariate alternative to multidimensional fast Fourier transform of multidimensional correlations. This method can be applied to short or sparse time series and can be extended to cross-trial and cross-channel spectra if multiple short data segments of the same experiment are available. Together, this time-domain toolbox provides higher temporal resolution, increased frequency and phase coupling information, and it allows an easy and straightforward implementation of higher-order spectra across time

  13. Time Delay Cosmography

    CERN Document Server

    Treu, Tommaso

    2016-01-01

    Gravitational time delays, observed in strong lens systems where the variable background source is multiply-imaged by a massive galaxy in the foreground, provide direct measurements of cosmological distance that are very complementary to other cosmographic probes. The success of the technique depends on the availability and size of a suitable sample of lensed quasars or supernovae, precise measurements of the time delays, accurate modeling of the gravitational potential of the main deflector, and our ability to characterize the distribution of mass along the line of sight to the source. We review the progress made during the last 15 years, during which the first competitive cosmological inferences with time delays were made, and look ahead to the potential of significantly larger lens samples in the near future.

  14. Prediction of delayed subsidence

    Science.gov (United States)

    Burns, K.

    A predictive model of delayed subsidence is discussed. A numerical implementation is tested on one of the best-described study areas, Allegheny County in Pennsylvania. In planning insurance of restitution measures, a predictive model is of value in estimating the magnitude of the problem and the size of long-term budgetary commitments. Contrary to active subsidence, which occurs concurrently with mining operations, or is completed within a few days following coal extraction, delayed subsidence may take many years to appear at the surface after coal mines are abandoned. There are two principal morphological types of delayed subsidence: troughs, which are shallow depressions, and sinks, which are steep-sided crown pits. Both types are damaging to surface structures, and a variety of methods were introduced to deal with the problem, ranging from subsidence insurance to site restitution.

  15. Time delay cosmography

    Science.gov (United States)

    Treu, Tommaso; Marshall, Philip J.

    2016-07-01

    Gravitational time delays, observed in strong lens systems where the variable background source is multiply imaged by a massive galaxy in the foreground, provide direct measurements of cosmological distance that are very complementary to other cosmographic probes. The success of the technique depends on the availability and size of a suitable sample of lensed quasars or supernovae, precise measurements of the time delays, accurate modeling of the gravitational potential of the main deflector, and our ability to characterize the distribution of mass along the line of sight to the source. We review the progress made during the last 15 years, during which the first competitive cosmological inferences with time delays were made, and look ahead to the potential of significantly larger lens samples in the near future.

  16. Delayed Random Relays

    CERN Document Server

    Ohira, Toru

    2016-01-01

    We present here a system with collection of random walks relaying a signal in one dimension with a presence of a delay. We are interested in the time for a signal to travel from one end (start) to the other end (finish) of the lined group of random walkers. It is found that there is an optimal number of walkers for the signal to travel fastest if the delay is present. We discuss implications of this model and associated behaviors to physical and biological systems.

  17. Approximation of distributed delays

    CERN Document Server

    Lu, Hao; Eberard, Damien; Simon, Jean-Pierre

    2010-01-01

    We address in this paper the approximation problem of distributed delays. Such elements are convolution operators with kernel having bounded support, and appear in the control of time-delay systems. From the rich literature on this topic, we propose a general methodology to achieve such an approximation. For this, we enclose the approximation problem in the graph topology, and work with the norm defined over the convolution Banach algebra. The class of rational approximates is described, and a constructive approximation is proposed. Analysis in time and frequency domains is provided. This methodology is illustrated on the stabilization control problem, for which simulations results show the effectiveness of the proposed methodology.

  18. Synchronization of time-delay coupled pulse oscillators

    Energy Technology Data Exchange (ETDEWEB)

    Klinshov, V.V., E-mail: vklin@mail.r [Institute of Applied Physics, Russian Academy of Sciences, 46 Ulyanov Str., 603950 Nizhny Novgorod (Russian Federation); Nekorkin, V.I. [Institute of Applied Physics, Russian Academy of Sciences, 46 Ulyanov Str., 603950 Nizhny Novgorod (Russian Federation)

    2011-01-15

    Research highlights: Oscillators can be synchronized via coupling with arbitrary large delay. Imposing of coupling delay may either result in delay-induced synchronization or delay-induced desynchronization. In-phase and antiphase synchronization zones alternate in parameter space. Two types of transitions between the in-phase and antiphase synchronization, i.e. phase-flip bifurcation and soft switching. - Abstract: We present a detailed study of the dynamics of pulse oscillators with time-delayed coupling. We get the return maps, obtain strict solutions and analyze their stability. For the case of two oscillators, a periodical structure of synchronization regions is found in parameter space, and the regions corresponding to in-phase and antiphase regimes alternate with growth of time delay. Two types of switching between in-phase and antiphase regimes are studied. We also show that for different parameters coupling delay may have synchronizing or desynchronizing effect. Another novel result is that phase locked regimes exist for arbitrary large values. The specificity of system dynamics with large delay is studied.

  19. Postural adjustments are modulated by manual task complexity

    Directory of Open Access Journals (Sweden)

    Luis Augusto Teixeira

    2009-09-01

    Full Text Available Daily life activities of humans are characterized by dual tasks, in which a manual task is performed concomitantly with a postural task. Based on the assumption that both manual and postural tasks require attentional resources, no consensus exists as to how the central nervous system modulates postural adjustments in dual tasks. The aim of the present study was to analyze the effect of a manual task requiring attentional resources on shoulder and ankle adjustments as a function of the direction and predictability of postural perturbation. The participants (n=6 were evaluated during the performance of a simple and a complex manual task, while the base of support was moved backward or forward. Latency of activation of the tibialis anterior and gastroc-nemius muscles and angular acceleration of the shoulder were analyzed. The results showed that execution of the complex manual task delayed postural adjustment. Moreover, this delay occurred differently depending on the direction of postural perturbation. The delay in postural adjustment occurred proximally in the case of anterior displacement of the platform, and distally in the case of posterior displacement. Postural adjustments were more affected by the attentional task than by the predictability of platform displacement. These results are consistent with the concept of an integrated control between manual actions and the maintenance of static posture.

  20. Exploration of the Reasons for Delays in Construction

    DEFF Research Database (Denmark)

    Lindhard, Søren Munch; Wandahl, Søren

    2014-01-01

    : connecting work, change in work plans, workforce, external conditions, material and construction design. Furthermore, the study revealed five seldom-occurring causes to delay: space, equipment, rework, unexpected conditions, and safety. The findings have been structured in accordance to the preconditions......Construction sites are dominated by chaos and complexity, enforcing challenging conditions for establishing reliable and robust schedules that are easy to observe. The consequence is a large amount of delayed activities that again results in an unreliable schedule. Last planner system (LPS......) was introduced as a production planning and control system to increase the reliability of scheduling task. By focusing on the removal of constraints, the LPS has successfully decreased the number of delayed activities. To further decrease delays, this research investigates the causes for delays at three...

  1. Anticipatory activity in rat medial prefrontal cortex during a working memory task

    Institute of Scientific and Technical Information of China (English)

    Wenwen Bai; Tiaotiao Liu; Hu Yi; Shuangyan Li; Xin Tian

    2012-01-01

    Objective Working memory is a key cognitive function in which the prefrontal cortex plays a crucial role.This study aimed to show the firing patterns of a neuronal population in the prefrontal cortex of the rat in a working memory task and to explore how a neuronal ensemble encodes a working memory event.Methods Sprague-Dawley rats were trained in a Y-maze until they reached an 80% correct rate in a working memory task.Then a 16-channel microelectrode array was implanted in the prefrontal cortex.After recovery,neuronal population activity was recorded during the task,using the Cerebus data-acquisition system.Spatio-temporal trains of action potentials were obtained from the original neuronal population signals.Results During the Y-maze working memory task,some neurons showed significantly increased firing rates and evident neuronal ensemble activity.Moreover,the anticipatory activity was associated with the delayed alternate choice of the upcoming movement.In correct trials,the averaged pre-event firing rate (10.86 ± 1.82 spikes/bin) was higher than the post-event rate (8.17 ± 1.15 spikes/bin) (P <0.05).However,in incorrect trials,the rates did not differ.Conclusion The results indicate that the anticipatory activity of a neuronal ensemble in the prefrontal cortex may play a role in encoding working memory events.

  2. "Task" as Research Construct

    Science.gov (United States)

    Seedhouse, Paul

    2005-01-01

    The article examines "task" as research construct as predominantly conceived in terms of task-as-workplan in the task-based learning/second language acquisition literature. It is suggested that "task" has weak construct validity and ontology in an overwhelmingly quantitative paradigm because the construct has a "split personality."…

  3. A Scheduling Algorithm Based on Communication Delay for Wireless Network Control System

    Directory of Open Access Journals (Sweden)

    Jun Wang

    2012-09-01

    Full Text Available In this study, a scheduling algorithm based on communication delay is proposed. This scheduling algorithm can tolerate delay of periodic communication tasks in wireless network control system. It resolves real-time problem of periodic communication tasks in wireless network control system and partly reduces overtime phenomenon of periodic communication tasks caused by delay in wireless network. At the same time, the nonlinear programming model is built for solving scheduling timetable based on the proposed scheduling algorithm. Finally, the performance of the proposed scheduling algorithm is evaluated by an application example. The statistics results show that it is more effective than traditional scheduling algorithms in wireless network control system.

  4. Variable sampling approach to mitigate instability in networked control systems with delays.

    Science.gov (United States)

    López-Echeverría, Daniel; Magaña, Mario E

    2012-01-01

    This paper analyzes a new alternative approach to compensate for the effects of time delays on a dynamic networked control system (NCS). The approach is based on the use of time-delay-predicted values as the sampling times of the NCS. We use a one-step-ahead prediction algorithm based on an adaptive time delay neural network. The application of pole placement and linear quadratic regulator methods to compute the feedback gains taking into account the estimated time delays is investigated.

  5. Delay Bounds for Multiclass FIFO

    OpenAIRE

    Jiang, Yuming; Misra, Vishal

    2016-01-01

    FIFO is perhaps the simplest scheduling discipline. For single-class FIFO, its delay guarantee performance has been extensively studied: The well-known results include a stochastic delay bound for $GI/GI/1$ by Kingman and a deterministic delay bound for $D/D/1$ by Cruz. However, for multiclass FIFO, few such results are available. To fill the gap, we prove delay bounds for multiclass FIFO in this work, considering both deterministic and stochastic cases. Specifically, delay bounds are present...

  6. The Marshmallow Test: Delay of Gratification and Independent Rule Compliance

    OpenAIRE

    Saxler, Patricia Kasak

    2016-01-01

    The Marshmallow Test, a self-imposed delay of gratification task pioneered by Walter Mischel in the 1960’s, showed that young children vary in their ability to inhibit impulses and regulate their attention and emotion in order to wait and obtain a desired reward (Mischel & Mischel, 1983). The Marshmallow Test offers an opportunity to observe and measure children’s decision-making and self-regulation in an emotionally charged context of often conflicting motivations. Additionally, this task p...

  7. Delayed breast implant reconstruction

    DEFF Research Database (Denmark)

    Hvilsom, Gitte B.; Hölmich, Lisbet R.; Steding-Jessen, Marianne;

    2012-01-01

    We evaluated the association between radiation therapy and severe capsular contracture or reoperation after 717 delayed breast implant reconstruction procedures (288 1- and 429 2-stage procedures) identified in the prospective database of the Danish Registry for Plastic Surgery of the Breast during...... reconstruction approaches other than implants should be seriously considered among women who have received radiation therapy....

  8. Delayed traumatic diaphragmatic hernia

    Science.gov (United States)

    Lu, Jing; Wang, Bo; Che, Xiangming; Li, Xuqi; Qiu, Guanglin; He, Shicai; Fan, Lin

    2016-01-01

    Abstract Background: Traumatic diaphragmatic hernias (TDHs) are sometimes difficult to identify at an early stage and can consequently result in diagnostic delays with life-threatening outcomes. It is the aim of this case study to highlight the difficulties encountered with the earlier detection of traumatic diaphragmatic hernias. Methods: Clinical data of patients who received treatment for delayed traumatic diaphragmatic hernias in registers of the First Affiliated Hospital of Xi’an Jiaotong University from 1998 to 2014 were analyzed retrospectively. Results: Six patients were included in this study. Left hemidiaphragm was affected in all of them. Most of the patients had a history of traffic accident and 1 a stab-penetrating injury. The interval from injury to developing symptoms ranged from 2 to 11 years (median 5 years). The hernial contents included the stomach, omentum, small intestine, and colon. Diaphragmatic injury was missed in all of them during the initial managements. All patients received operations once the diagnosis of delayed TDH was confirmed, and no postoperative mortality was detected. Conclusions: Delayed TDHs are not common, but can lead to serious consequences once occurred. Early detection of diaphragmatic injuries is crucial. Surgeons should maintain a high suspicion for injuries of the diaphragm in cases with abdominal or lower chest traumas, especially in the initial surgical explorations. We emphasize the need for radiographical follow-up to detect diaphragmatic injuries at an earlier stage. PMID:27512848

  9. 'No delays achiever'.

    Science.gov (United States)

    2007-05-01

    The latest version of the NHS Institute for Innovation and Improvement's 'no delays achiever', a web based tool created to help NHS organisations achieve the 18-week target for GP referrals to first treatment, is available at www.nodelaysachiever.nhs.uk.

  10. Permissible Delay in Payments

    Directory of Open Access Journals (Sweden)

    Yung-Fu Huang

    2007-01-01

    Full Text Available The main purpose of this paper wants to investigate the optimal retailer's lot-sizing policy with two warehouses under partially permissible delay in payments within the economic order quantity (EOQ framework. In this paper, we want to extend that fully permissible delay in payments to the supplier would offer the retailer partially permissible delay in payments. That is, the retailer must make a partial payment to the supplier when the order is received. Then the retailer must pay off the remaining balance at the end of the permissible delay period. In addition, we want to add the assumption that the retailer's storage space is limited. That is, the retailer will rent the warehouse to store these exceeding items when the order quantity is larger than retailer's storage space. Under these conditions, we model the retailer's inventory system as a cost minimization problem to determine the retailer's optimal cycle time and optimal order quantity. Three theorems are developed to efficiently determine the optimal replenishment policy for the retailer. Finally, numerical examples are given to illustrate these theorems and obtained a lot of managerial insights.

  11. Delayed fluorescence in photosynthesis.

    Science.gov (United States)

    Goltsev, Vasilij; Zaharieva, Ivelina; Chernev, Petko; Strasser, Reto J

    2009-01-01

    Photosynthesis is a very efficient photochemical process. Nevertheless, plants emit some of the absorbed energy as light quanta. This luminescence is emitted, predominantly, by excited chlorophyll a molecules in the light-harvesting antenna, associated with Photosystem II (PS II) reaction centers. The emission that occurs before the utilization of the excitation energy in the primary photochemical reaction is called prompt fluorescence. Light emission can also be observed from repopulated excited chlorophylls as a result of recombination of the charge pairs. In this case, some time-dependent redox reactions occur before the excitation of the chlorophyll. This delays the light emission and provides the name for this phenomenon-delayed fluorescence (DF), or delayed light emission (DLE). The DF intensity is a decreasing polyphasic function of the time after illumination, which reflects the kinetics of electron transport reactions both on the (electron) donor and the (electron) acceptor sides of PS II. Two main experimental approaches are used for DF measurements: (a) recording of the DF decay in the dark after a single turnover flash or after continuous light excitation and (b) recording of the DF intensity during light adaptation of the photosynthesizing samples (induction curves), following a period of darkness. In this paper we review historical data on DF research and recent advances in the understanding of the relation between the delayed fluorescence and specific reactions in PS II. An experimental method for simultaneous recording of the induction transients of prompt and delayed chlorophyll fluorescence and decay curves of DF in the millisecond time domain is discussed.

  12. Recalling academic tasks

    Science.gov (United States)

    Draper, Franklin Gno

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

  13. The effect of task complexity and task conditions on foreign language development and performance: three empirical studies

    OpenAIRE

    Sercu, L.; 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 in such a way that they optimally support and promote the L2 learning process. Knowing what demands a task will make opens up the possibility of using task design to manipulate the learner's atten...

  14. Kokkos? Task DAG Capabilities.

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, Harold C.; Ibanez, Daniel Alejandro

    2017-09-01

    This report documents the ASC/ATDM Kokkos deliverable "Production Portable Dy- namic Task DAG Capability." This capability enables applications to create and execute a dynamic task DAG ; a collection of heterogeneous computational tasks with a directed acyclic graph (DAG) of "execute after" dependencies where tasks and their dependencies are dynamically created and destroyed as tasks execute. The Kokkos task scheduler executes the dynamic task DAG on the target execution resource; e.g. a multicore CPU, a manycore CPU such as Intel's Knights Landing (KNL), or an NVIDIA GPU. Several major technical challenges had to be addressed during development of Kokkos' Task DAG capability: (1) portability to a GPU with it's simplified hardware and micro- runtime, (2) thread-scalable memory allocation and deallocation from a bounded pool of memory, (3) thread-scalable scheduler for dynamic task DAG, (4) usability by applications.

  15. Subspace-based identification of discrete time-delay system

    Institute of Scientific and Technical Information of China (English)

    Qiang LIU; Jia-chen MA

    2016-01-01

    We investigate the identification problems of a class of linear stochastic time-delay systems with unknown delayed states in this study. A time-delay system is expressed as a delay differential equation with a single delay in the state vector. We first derive an equivalent linear time-invariant (LTI) system for the time-delay system using a state augmentation technique. Then a conventional subspace identification method is used to estimate augmented system matrices and Kalman state sequences up to a similarity transformation. To obtain a state-space model for the time-delay system, an alternate convex search (ACS) algorithm is presented to find a similarity transformation that takes the identified augmented system back to a form so that the time-delay system can be recovered. Finally, we reconstruct the Kalman state sequences based on the similarity transformation. The time-delay system matrices under the same state-space basis can be recovered from the Kalman state sequences and input-output data by solving two least squares problems. Numerical examples are to show the effectiveness of the proposed method.

  16. Data-assimilation by delay-coordinate nudging

    CERN Document Server

    Pazó, D; López, J M

    2015-01-01

    A new nudging method for data assimilation, delay-coordinate nudging, is presented. Delay-coordinate nudging makes explicit use of present and past observations in the formulation of the forcing driving the model evolution at each time-step. Numerical experiments with a low order chaotic system show that the new method systematically outperforms standard nudging in different model and observational scenarios, also when using an un-optimized formulation of the delay-nudging coefficients. A connection between the optimal delay and the dominant Lyapunov exponent of the dynamics is found based on heuristic arguments and is confirmed by the numerical results, providing a guideline for the practical implementation of the algorithm. Delay-coordinate nudging preserves the easiness of implementation, the intuitive functioning and the reduced computational cost of the standard nudging, making it a potential alternative especially in the field of seasonal-to-decadal predictions with large Earth system models that limit ...

  17. The unidirectional prosaccade switch-cost: electroencephalographic evidence of task-set inertia in oculomotor control.

    Science.gov (United States)

    Weiler, Jeffrey; Hassall, Cameron D; Krigolson, Olave E; Heath, Matthew

    2015-02-01

    The execution of an antisaccade selectively increases the reaction time (RT) of a subsequent prosaccade (the unidirectional prosaccade switch-cost). To explain this finding, the task-set inertia hypothesis asserts that an antisaccade requires a cognitively mediated non-standard task-set that persists inertially and delays the planning of a subsequent prosaccade. The present study sought to directly test the theoretical tenets of the task-set inertia hypothesis by examining the concurrent behavioural and the event-related brain potential (ERP) data associated with the unidirectional prosaccade switch-cost. Participants pseudo-randomly alternated between pro- and antisaccades while electroencephalography (EEG) data were recorded. As expected, the completion of an antisaccade selectively increased the RT of a subsequent prosaccade, whereas the converse switch did not influence RTs. Thus, the behavioural results demonstrated the unidirectional prosaccade switch-cost. In terms of the ERP findings, we observed a reliable change in the amplitude of the P3 - time-locked to task-instructions - when trials were switched from a prosaccade to an antisaccade; however, no reliable change was observed when switching from an antisaccade to a prosaccade. This is a salient finding because extensive work has shown that the P3 provides a neural index of the task-set required to execute a to-be-completed response. As such, results showing that prosaccades completed after antisaccades exhibited increased RTs in combination with a P3 amplitude comparable to antisaccades provides convergent evidence that the unidirectional prosaccade switch-cost is attributed to the persistent activation of a non-standard antisaccade task-set.

  18. Delay discounting of food by rhesus monkeys: Cocaine and food choice in isomorphic and allomorphic situations.

    Science.gov (United States)

    Huskinson, Sally L; Woolverton, William L; Green, Leonard; Myerson, Joel; Freeman, Kevin B

    2015-06-01

    Research on delay discounting has focused largely on nondrug reinforcers in an isomorphic context in which choice is between alternatives that involve the same type of reinforcer. Less often, delay discounting has been studied with drug reinforcers in a more ecologically valid allomorphic context where choice is between alternatives involving different types of reinforcers. The present experiment is the first to examine discounting of drug and nondrug reinforcers in both isomorphic and allomorphic situations using a theoretical model (i.e., the hyperbolic discounting function) that allows for comparisons of discounting rates between reinforcer types and amounts. The goal of the current experiment was to examine discounting of a delayed, nondrug reinforcer (food) by male rhesus monkeys when the immediate alternative was either food (isomorphic situation) or cocaine (allomorphic situation). In addition, we sought to determine whether there was a magnitude effect with delayed food in the allomorphic situation. Choice of immediate food and immediate cocaine increased with amount and dose, respectively. Choice functions for immediate food and cocaine generally shifted leftward as delay increased. Compared to isomorphic situations in which food was the immediate alternative, delayed food was discounted more steeply in allomorphic situations where cocaine was the immediate alternative. Notably, discounting was not affected by the magnitude of the delayed reinforcer. These data indicate that how steeply a delayed nondrug reinforcer is discounted may depend more on the qualitative characteristics of the immediate reinforcer and less on the magnitude of the delayed one. (c) 2015 APA, all rights reserved).

  19. Delay-independent stabilization for teleoperation with time varying delay

    OpenAIRE

    Fujita, Hiroyuki; Namerikawa, Toru

    2009-01-01

    This paper deals with the stability for nonlinear teleoperation with time varying communication delays. The proposed method is passivity-based controllers with time varying gains which depend on the rate of change of time varying delay. In our proposed method, stability condition is independent of the magnitude of the communication delay and the damping of the system. The delay-independent stability is shown via Lyapunov stability methods. Several experimental results show the effectiveness o...

  20. NARX neural networks for sequence processing tasks

    OpenAIRE

    Hristev, Eugen

    2012-01-01

    This project aims at researching and implementing a neural network architecture system for the NARX (Nonlinear AutoRegressive with eXogenous inputs) model, used in sequence processing tasks and particularly in time series prediction. The model can fallback to different types of architectures including time-delay neural networks and multi layer perceptron. The NARX simulator tests and compares the different architectures for both synthetic and real data, including the time series o...

  1. [Striated and delayed nephrography].

    Science.gov (United States)

    Marlois, O; Padovani, J; Faure, F; Devred, P; Grangier, M L; Panuel, M

    1985-10-01

    About a case of striated and delayed nephrogram seen on a diabetic child, authors come back to the different etiologies. Among them, the tubular precipitation of Tamm-Horsfall protein seems to be given like on the right possibilities. Whatever is its etiology, the mechanism of striated appearance is always the same, being founded on the radiated disposal of the collecting ducts and on a tubular stasis beeing with iodine concentration.

  2. Theoretical Delay Time Distributions

    CERN Document Server

    Nelemans, Gijs; Bours, Madelon

    2012-01-01

    We briefly discuss the method of population synthesis to calculate theoretical delay time distributions of type Ia supernova progenitors. We also compare the results of the different research groups and conclude that although one of the main differences in the results for single degenerate progenitors is the retention efficiency with which accreted hydrogen is added to the white dwarf core, this cannot explain all the differences.

  3. Theoretical Delay Time Distributions

    Science.gov (United States)

    Nelemans, Gijs; Toonen, Silvia; Bours, Madelon

    2013-01-01

    We briefly discuss the method of population synthesis to calculate theoretical delay time distributions of Type Ia supernova progenitors. We also compare the results of different research groups and conclude that, although one of the main differences in the results for single degenerate progenitors is the retention efficiency with which accreted hydrogen is added to the white dwarf core, this alone cannot explain all the differences.

  4. Geometric Time Delay Interferometry

    OpenAIRE

    Vallisneri, Michele

    2005-01-01

    The space-based gravitational-wave observatory LISA, a NASA-ESA mission to be launched after 2012, will achieve its optimal sensitivity using Time Delay Interferometry (TDI), a LISA-specific technique needed to cancel the otherwise overwhelming laser noise in the inter-spacecraft phase measurements. The TDI observables of the Michelson and Sagnac types have been interpreted physically as the virtual measurements of a synthesized interferometer. In this paper, I present Geometric TDI, a new an...

  5. Time-Delay Interferometry

    OpenAIRE

    Dhurandhar Sanjeev V.; Tinto Massimo

    2005-01-01

    Equal-arm interferometric detectors of gravitational radiation allow phase measurements many orders of magnitude below the intrinsic phase stability of the laser injecting light into their arms. This is because the noise in the laser light is common to both arms, experiencing exactly the same delay, and thus cancels when it is differenced at the photo detector. In this situation, much lower level secondary noises then set overall performance. If, however, the two arms have different lengths (...

  6. Delay propagation and process management at railway stations

    NARCIS (Netherlands)

    Goverde, R.M.P.; Hansen, I.A.

    2001-01-01

    Process operators at large railway stations have the difficult task to secure a fluent train traffic flow while minimizing deviations from established timetables. Variation in actual train departure times is inevitable due to many circumstances such as arrival delays and fluctuations in alighting an

  7. Gender differences in delay-discounting under mild food restriction

    NARCIS (Netherlands)

    Koot, S.; van den Bos, R.; Adriani, W.; Laviola, G.

    2009-01-01

    Abstract: Impulsivity, a core symptomof attention-deficit hyperactivity disorder (ADHD), is tested in animal models by delay-discounting tasks. So far, mainly male subjects have been used in this paradigm at severe levels of food restriction. Here we studied the impulsive behaviour of CD-1 adult mal

  8. Delay propagation and process management at railway stations

    NARCIS (Netherlands)

    Goverde, R.M.P.; Hansen, I.A.

    2001-01-01

    Process operators at large railway stations have the difficult task to secure a fluent train traffic flow while minimizing deviations from established timetables. Variation in actual train departure times is inevitable due to many circumstances such as arrival delays and fluctuations in alighting

  9. Delay in atomic photoionization

    CERN Document Server

    Kheifets, A S

    2010-01-01

    We analyze the time delay between emission of photoelectrons from the outer valence $ns$ and $np$ sub-shells in noble gas atoms following absorption of an attosecond XUV pulse. By solving the time dependent Schr\\"odinger equation and carefully examining the time evolution of the photoelectron wave packet, we establish the apparent "time zero" when the photoelectron leaves the atom. Various processes such as elastic scattering of the photoelectron on the parent ion and many-electron correlation affect the quantum phase of the dipole transition matrix element, the energy dependence of which defines the emission timing. This qualitatively explains the time delay between photoemission from the $2s$ and $2p$ sub-shells of Ne as determined experimentally by attosecond streaking [{\\em Science} {\\bf 328}, 1658 (2010)]. However, with our extensive numerical modeling, we were only able to account for less than a half of the measured time delay of $21\\pm5$~as. We argue that the XUV pulse alone cannot produce such a larg...

  10. Time-Delay Interferometry

    Directory of Open Access Journals (Sweden)

    Massimo Tinto

    2014-08-01

    Full Text Available Equal-arm detectors of gravitational radiation allow phase measurements many orders of magnitude below the intrinsic phase stability of the laser injecting light into their arms. This is because the noise in the laser light is common to both arms, experiencing exactly the same delay, and thus cancels when it is differenced at the photo detector. In this situation, much lower level secondary noises then set the overall performance. If, however, the two arms have different lengths (as will necessarily be the case with space-borne interferometers, the laser noise experiences different delays in the two arms and will hence not directly cancel at the detector. In order to solve this problem, a technique involving heterodyne interferometry with unequal arm lengths and independent phase-difference readouts has been proposed. It relies on properly time-shifting and linearly combining independent Doppler measurements, and for this reason it has been called time-delay interferometry (TDI. This article provides an overview of the theory, mathematical foundations, and experimental aspects associated with the implementation of TDI. Although emphasis on the application of TDI to the Laser Interferometer Space Antenna (LISA mission appears throughout this article, TDI can be incorporated into the design of any future space-based mission aiming to search for gravitational waves via interferometric measurements. We have purposely left out all theoretical aspects that data analysts will need to account for when analyzing the TDI data combinations.

  11. Efficient Timetable Information in the Presence of Delays

    Science.gov (United States)

    Müller-Hannemann, Matthias; Schnee, Mathias

    The search for train connections in state-of-the-art commercial timetable information systems is based on a static schedule. Unfortunately, public transportation systems suffer from delays for various reasons. Thus, dynamic changes of the planned schedule have to be taken into account. A system that has access to delay information about trains (and uses this information within search queries) can provide valid alternatives in case a connection does not work. Additionally, it can be used to actively guide passengers as these alternatives may be presented before the passenger is already stranded at a station due to an invalid transfer.

  12. 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...

  13. Determining team cognition from delay analysis using cross recurrence plot.

    Science.gov (United States)

    Hajari, Nasim; Cheng, Irene; Bin Zheng; Basu, Anup

    2016-08-01

    Team cognition is an important factor in evaluating and determining team performance. Forming a team with good shared cognition is even more crucial for laparoscopic surgery applications. In this study, we analyzed the eye tracking data of two surgeons during a laparoscopic simulation operation, then performed Cross Recurrence Analysis (CRA) on the recorded data to study the delay behaviour for good performer and poor performer teams. Dual eye tracking data for twenty two dyad teams were recorded during a laparoscopic task and then the teams were divided into good performer and poor performer teams based on the task times. Eventually we studied the delay between two team members for good and poor performer teams. The results indicated that the good performer teams show a smaller delay comparing to poor performer teams. This study is compatible with gaze overlap analysis between team members and therefore it is a good evidence of shared cognition between team members.

  14. Alternative Energies

    Energy Technology Data Exchange (ETDEWEB)

    Planting, A.; De saint Jacob, Y.; Verwijs, H.; Belin, H.; Preesman, L.

    2009-03-15

    In two articles, one interview and one column attention is paid to alternative energies. The article 'A new light on saving energy' discusses the option to save energy by modernising lighting systems in urban areas. The column 'View from Paris' focuses on investment decisions in France with regard to renewable energy and energy savings. The article 'Europe turns a blind eye to big battery' discusses developments in batteries to store energy. The interview concerns fuel cell expert and formerly President of UTC Power Jan van Dokkum. The last article gives a brief overview of the European Energy Research Alliance (EERA) and the challenges this alliance will have to face with regard to climate change and energy security.

  15. Delayed Speech or Language Development

    Science.gov (United States)

    ... to 2-Year-Old Delayed Speech or Language Development KidsHealth > For Parents > Delayed Speech or Language Development ... child is right on schedule. Normal Speech & Language Development It's important to discuss early speech and language ...

  16. Spontaneous eye blinks during creative task correlate with divergent processing.

    Science.gov (United States)

    Ueda, Yoshiyuki; Tominaga, Atsuko; Kajimura, Shogo; Nomura, Michio

    2016-07-01

    Creativity consists of divergent and convergent thinking, with both related to individual eye blinks at rest. To assess underlying mechanisms between eye blinks and traditional creativity tasks, we investigated the relationship between creativity performance and eye blinks at rest and during tasks. Participants performed an alternative uses and remote association task while eye blinks were recorded. Results showed that the relationship between eye blinks at rest and creativity performance was compatible with those of previous research. Interestingly, we found that the generation of ideas increased as a function of eye blink number during the alternative uses task. On the other hand, during the remote association task, accuracy was independent of eye blink number during the task, but response time increased with it. Moreover, eye blink changes in participants who responded quickly during the remote association task were different depending on their resting state eye blinks; that is, participants with many eye blinks during rest showed little increasing eye blinks and achieved solutions quickly. Positive correlations between eye blinks during creative tasks and yielding ideas on the alternative uses task and response time on the remote association task suggest that eye blinks during creativity tasks relate to divergent thinking processes such as conceptual reorganization.

  17. Lost ability to automatize task performance in old age.

    Science.gov (United States)

    Maquestiaux, François; Didierjean, André; Ruthruff, Eric; Chauvel, Guillaume; Hartley, Alan

    2013-12-01

    Can elderly adults automatize a new task? To address this question, 10 older adults each performed 10,080 training trials over 12 sessions on an easy but novel task. The psychological refractory period (PRP) procedure was then used to evaluate whether this highly practiced task, when presented as task 2 along with an unpracticed task 1, could proceed automatically. If automatic, task 2 processing should bypass the bottleneck and, therefore, not be delayed while central attention is devoted to task 1, yielding little dual-task interference. This is exactly what Maquestiaux, Laguë-Beauvais, Ruthruff, and Bherer (Memory and Cognition 36:1262-1282, 2008) previously observed for almost all younger adults, even with half the training on a more difficult task. Although extensive training reduced older adults' reaction times to only 307 ms, a value virtually identical to that attained by Maquestiaux et al.'s (Memory and Cognition 36:1262-1282, 2008) younger adults, the highly practiced task 2 was slowed by 485 ms in the dual-task PRP procedure. Such a large slowing in older adults is striking given the easy tasks and massive amounts of practice. These findings demonstrate a qualitative change with age, in which older adults lose the ability to automatize novel tasks, which cannot be attributed merely to generalized cognitive slowing.

  18. Launching Complex Tasks

    Science.gov (United States)

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

    2012-01-01

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

  19. 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 fr

  20. Time delay measurement in the frequency domain

    Science.gov (United States)

    Durbin, Stephen M.; Liu, Shih-Chieh; Dufresne, Eric M.; Li, Yuelin; Wen, Haidan

    2015-01-01

    Pump–probe studies at synchrotrons using X-ray and laser pulses require accurate determination of the time delay between pulses. This becomes especially important when observing ultrafast responses with lifetimes approaching or even less than the X-ray pulse duration (∼100 ps). The standard approach of inspecting the time response of a detector sensitive to both types of pulses can have limitations due to dissimilar pulse profiles and other experimental factors. Here, a simple alternative is presented, where the frequency response of the detector is monitored versus time delay. Measurements readily demonstrate a time resolution of ∼1 ps. Improved precision is possible by simply extending the data acquisition time. PMID:26289282

  1. Exploiting Deterministic TPG for Path Delay Testing

    Institute of Scientific and Technical Information of China (English)

    李晓维

    2000-01-01

    Detection of path delay faults requires two-pattern tests. BIST technique provides a low-cost test solution. This paper proposes an approach to designing a cost-effective deterministic test pattern generator (TPG) for path delay testing. Given a set of pre-generated test-pairs with pre-determined fault coverage, a deterministic TPG is synthesized to apply the given test-pair set in a limited test time. To achieve this objective, configurable linear feedback shift register (LFSR) structures are used. Techniques are developed to synthesize such a TPG, which is used to generate an unordered deterministic test-pair set. The resulting TPG is very efficient in terms of hardware size and speed performance. Simulation of academic benchmark circuits has given good results when compared to alternative solutions.

  2. Delaying information search

    Directory of Open Access Journals (Sweden)

    Yaniv Shani

    2012-11-01

    Full Text Available In three studies, we examined factors that may temporarily attenuate information search. People are generally curious and dislike uncertainty, which typically encourages them to look for relevant information. Despite these strong forces that promote information search, people sometimes deliberately delay obtaining valuable information. We find they may do so when they are concerned that the information might interfere with future pleasurable activities. Interestingly, the decision to search or to postpone searching for information is influenced not only by the value and importance of the information itself but also by well-being maintenance goals related to possible detrimental effects that negative knowledge may have on unrelated future plans.

  3. Delay discounting and utility for money or weight loss.

    Science.gov (United States)

    Sze, Y Y; Slaven, E M; Bickel, W K; Epstein, L H

    2017-03-01

    Obesity is related to a bias towards smaller immediate over larger delayed rewards. This bias is typically examined by studying single commodity discounting. However, weight loss often involves choices among multiple commodities. To our knowledge, no research has examined delay discounting of delayed weight loss compared with other commodities. We examined single commodity discounting of money and cross commodity discounting of money and weight loss in a sample of 84 adults with obesity or overweight statuses interested in weight loss. The exchange rate between money and weight loss was calculated, and participants completed two delay discounting tasks: money now versus money later and money now versus weight loss later. Participants discounted weight loss more than money (p commodity discounting, and greater discounting of weight loss across all participants provide insight on important challenges for weight control.

  4. LIQUID PHASE FISCHER-TROPSCH (III & IV) DEMONSTRATION IN THE LAPORTE ALTERNATIVE FUELS DEVELOPMENT UNIT. Final Topical Report. Volume I/II: Main Report. Task 1: Engineering Modifications (Fischer-Tropsch III & IV Demonstration) and Task 2: AFDU Shakedown, Operations, Deactivation (Shut-Down) and Disposal (Fischer-Tropsch III & IV Demonstration).

    Energy Technology Data Exchange (ETDEWEB)

    Bharat L. Bhatt

    1999-06-01

    Slurry phase Fischer-Tropsch technology was successfully demonstrated in DOE's Alternative Fuels Development Unit (AFDU) at LaPorte, Texas. Earlier work at LaPorte, with iron catalysts in 1992 and 1994, had established proof-of-concept status for the slurry phase process. The third campaign (Fischer-Tropsch III), in 1996, aimed at aggressively extending the operability of the slurry reactor using a proprietary cobalt catalyst. Due to an irreversible plugging of catalyst-wax separation filters as a result of unexpected catalyst fines generation, the operations had to be terminated after seven days on-stream. Following an extensive post-run investigation by the participants, the campaign was successfully completed in March-April 1998, with an improved proprietary cobalt catalyst. These runs were sponsored by the U. S. Department of Energy (DOE), Air Products & Chemicals, Inc., and Shell Synthetic Fuels, Inc. (SSFI). A productivity of approximately 140 grams (gm) of hydrocarbons (HC)/ hour (hr)-liter (lit) of expanded slurry volume was achieved at reasonable system stability during the second trial (Fischer-Tropsch IV). The productivity ranged from 110-140 at various conditions during the 18 days of operations. The catalyst/wax filters performed well throughout the demonstration, producing a clean wax product. For the most part, only one of the four filter housings was needed for catalyst/wax filtration. The filter flux appeared to exceed the design flux. A combination of use of a stronger catalyst and some innovative filtration techniques were responsible for this success. There was no sign of catalyst particle attrition and very little erosion of the slurry pump was observed, in contrast to the Fischer-Tropsch III operations. The reactor operated hydrodynamically stable with uniform temperature profile and gas hold-ups. Nuclear density and differential pressure measurements indicated somewhat higher than expected gas hold-up (45 - 50 vol%) during Fischer

  5. Evaluation of DCS III Transmission Alternatives, Phase II, Task 1.

    Science.gov (United States)

    1981-08-31

    Virtual circuits vs. "real" circuits. Particularly those digital services based on advanced concentration and multiple access schemes may not meet the...amplifiers, filters, modems, and line interface circuits; these devices are necessary for the realization of fully integrated digital services (e.g

  6. The Creative task Creator: a tool for the generation of customized, Web-based creativity tasks.

    Science.gov (United States)

    Pretz, Jean E; Link, John A

    2008-11-01

    This article presents a Web-based tool for the creation of divergent-thinking and open-ended creativity tasks. A Java program generates HTML forms with PHP scripting that run an Alternate Uses Task and/or open-ended response items. Researchers may specify their own instructions, objects, and time limits, or use default settings. Participants can also be prompted to select their best responses to the Alternate Uses Task (Silvia et al., 2008). Minimal programming knowledge is required. The program runs on any server, and responses are recorded in a standard MySQL database. Responses can be scored using the consensual assessment technique (Amabile, 1996) or Torrance's (1998) traditional scoring method. Adoption of this Web-based tool should facilitate creativity research across cultures and access to eminent creators. The Creative Task Creator may be downloaded from the Psychonomic Society's Archive of Norms, Stimuli, and Data, www.psychonomic.org/archive.

  7. Strategic Adaptation to Task Characteristics, Incentives, and Individual Differences in Dual-Tasking.

    Directory of Open Access Journals (Sweden)

    Christian P Janssen

    Full Text Available We investigate how good people are at multitasking by comparing behavior to a prediction of the optimal strategy for dividing attention between two concurrent tasks. In our experiment, 24 participants had to interleave entering digits on a keyboard with controlling a randomly moving cursor with a joystick. The difficulty of the tracking task was systematically varied as a within-subjects factor. Participants were also exposed to different explicit reward functions that varied the relative importance of the tracking task relative to the typing task (between-subjects. Results demonstrate that these changes in task characteristics and monetary incentives, together with individual differences in typing ability, influenced how participants choose to interleave tasks. This change in strategy then affected their performance on each task. A computational cognitive model was used to predict performance for a wide set of alternative strategies for how participants might have possibly interleaved tasks. This allowed for predictions of optimal performance to be derived, given the constraints placed on performance by the task and cognition. A comparison of human behavior with the predicted optimal strategy shows that participants behaved near optimally. Our findings have implications for the design and evaluation of technology for multitasking situations, as consideration should be given to the characteristics of the task, but also to how different users might use technology depending on their individual characteristics and their priorities.

  8. Are spatial responses to visuospatial stimuli and spoken responses to auditory letters ideomotor-compatible tasks? Examination of set-size effects on dual-task interference.

    Science.gov (United States)

    Shin, Yun-Kyoung; Proctor, Robert W

    2008-11-01

    Previous studies have paired a visual-manual Task 1 with an auditory-vocal Task 2 to evaluate whether the psychological refractory period (PRP) effect is eliminated with two ideomotor-compatible tasks (for which stimuli resemble the response feedback). The present study varied the number of stimulus-response alternatives for Task 1 in three experiments to determine whether set-size and PRP effects were absent, as would be expected if the tasks bypass limited-capacity response-selection processes. In Experiments 1 and 2, the visual-manual task was used as Task 1, with lever-movement and keypress responses, respectively. In Experiment 3, the auditory-vocal task was used as Task 1 and the visual-manual task as Task 2. A significant lengthening of reaction time for 4 vs. 2 alternatives was found for the visual-manual Task 1 and the Task 2 PRP effect in Experiments 1 and 2, suggesting that the visual-manual task is not ideomotor compatible. Neither effect of set size was significant for the auditory-vocal Task 1 in Experiment 3, but there was still a Task 2 PRP effect. Our results imply that neither version of the visual-manual task is ideomotor compatible; other considerations suggest that the auditory-vocal task may also still require response selection.

  9. Pseudotumoral delayed cerebral radionecrosis

    Energy Technology Data Exchange (ETDEWEB)

    Ciaudo-Lacroix, C.; Lapresle, J. (Centre Hospitalier de Bicetre, 94 - Le Kremlin-Bicetre (France))

    1985-01-01

    A 60 year-old woman with a scalp epithelioma underwent radiotherapy, the dose being 57 Gray. A first epileptic seizure occurred twenty months later. Neurological examination revealed signs of left hemisphere involvement. ..gamma..EG, angiography, CT scans, demonstrated a pseudotumoral avascular process. On account of the localisation, the patient being right-handed, no surgical procedure was performed. In spite of corticotherapy and anticonvulsive treatment, seizures recurred and neurological signs slowly progressed. The patient died, 22 months after the first seizure, of an associated disseminated carcinoma with cachexia. Neuropathological examination showed a massive lesion presenting all the features of delayed radionecrosis in the left hemisphere: situated mainly in the white matter; numerous vascular abnormalities; wide-spread demyelination; disappearance of oligoglial cells. The Authors recall the clinical and anatomical aspects of this condition for which the only successful treatment is surgical removal when location and size of the lesion permit. Finally, the mechanisms which have been proposed to explain this delayed cerebral radionecrosis are discussed.

  10. Epidemiology of delayed ejaculation.

    Science.gov (United States)

    Di Sante, Stefania; Mollaioli, Daniele; Gravina, Giovanni Luca; Ciocca, Giacomo; Limoncin, Erika; Carosa, Eleonora; Lenzi, Andrea; Jannini, Emmanuele A

    2016-08-01

    A large body of literature on diminished ejaculatory disorders has been generated without the use of a clear diagnostic definition. Many studies have not distinguished between the orgasm and ejaculation disorders leading to doubtful results. Delayed ejaculation (DE) is one of the diminished ejaculatory disorders, which range from varying delays in ejaculatory latency to a complete inability to ejaculate. The present review is aimed at providing a comprehensive overview of the current knowledge on the definition and epidemiology of diminished ejaculatory disorders. We focus on the acquired diseases, such as benign prostatic hyperplasia (BPH) and specific drug regimens that may cause an iatrogenic form of ejaculatory disorder. In addition, the impact of aging is discussed since the prevalence of DE appears to be moderately but positively related to age. Finally, we also focus on the importance of the hormonal milieu on male ejaculation. To date, evidence on the endocrine control of ejaculation is derived from small clinical trials, but the evidence suggests that hormones modulate the ejaculatory process by altering its overall latency.

  11. Overview of the ID, EPI and REL tasks of BioNLP Shared Task 2011

    Directory of Open Access Journals (Sweden)

    Pyysalo Sampo

    2012-06-01

    of performance sufficient for user-facing applications. In this study, we extend on previously reported results and perform further analyses of the outputs of the participating systems. We place specific emphasis on aspects of system performance relating to real-world applicability, considering alternate evaluation metrics and performing additional manual analysis of system outputs. We further demonstrate that the strengths of extraction systems can be combined to improve on the performance achieved by any system in isolation. The manually annotated corpora, supporting resources, and evaluation tools for all tasks are available from http://www.bionlp-st.org and the tasks continue as open challenges for all interested parties.

  12. A Comparative Study of Task-based vs. Task- supported Teaching Approaches in an EFL Context

    OpenAIRE

    Mahdieh Shafipoor; Farnaz Latif

    2015-01-01

    In spite of the numerous merits of task-based language instruction as claimed by its supporters in the last few decades, task-supported teaching approach as an alternative was introduced. Since then, there have been controversial debates over the superiority of each of these two approaches. Thus, in the current research project, the purpose was to consider these two teaching approaches in the scope of English language teaching, with the purpose of exploring the most efficient one in an Irania...

  13. Stability and delay sensitivity of neutral fractional-delay systems

    Science.gov (United States)

    Xu, Qi; Shi, Min; Wang, Zaihua

    2016-08-01

    This paper generalizes the stability test method via integral estimation for integer-order neutral time-delay systems to neutral fractional-delay systems. The key step in stability test is the calculation of the number of unstable characteristic roots that is described by a definite integral over an interval from zero to a sufficient large upper limit. Algorithms for correctly estimating the upper limits of the integral are given in two concise ways, parameter dependent or independent. A special feature of the proposed method is that it judges the stability of fractional-delay systems simply by using rough integral estimation. Meanwhile, the paper shows that for some neutral fractional-delay systems, the stability is extremely sensitive to the change of time delays. Examples are given for demonstrating the proposed method as well as the delay sensitivity.

  14. Saccades and fixations in children with delayed reading skills.

    Science.gov (United States)

    Vinuela-Navarro, Valldeflors; Erichsen, Jonathan T; Williams, Cathy; Woodhouse, J Margaret

    2017-07-01

    Previous studies have reported that eye movements differ between good/average and poor readers. However, these studies have been limited to investigating eye movements during reading related tasks, and thus, the differences found could arise from deficits in higher cognitive processes involved in reading rather than oculomotor performance. The purpose of the study is to determine the extent to which eye movements in children with delayed reading skills are different to those obtained from children with good/average reading skills in non-reading related tasks. After a screening optometric assessment, eye movement recordings were obtained from 120 children without delayed reading skills and 43 children with delayed reading skills (4 to 11 years) using a Tobii TX300 eye tracker. Cartoon characters were presented horizontally from -20° to +20° in steps of 5° to study saccades. An animated stimulus in the centre of the screen was presented for 8 seconds to study fixation stability. Saccadic main sequences, and the number and amplitude of the saccades during fixation were obtained for each participant. Children with delayed reading skills (n = 43) were unmasked after data collection was completed. Medians and quartiles were calculated for each eye movement parameter for children without (n = 120) and with (n = 43) delayed reading skills. Independent t-tests with Bonferroni correction showed no significant differences in any of the saccadic main sequence parameters (Slope, Intercept, A, n and Q ratio) between children without and with delayed reading (p > 0.01). Similarly, no significant differences were found in the number of saccades and their amplitude during the fixation task between the two groups (p > 0.05). Further, none of the gross optometric parameters assessed (visual acuity, refractive error, ocular alignment, convergence, stereopsis and accommodation accuracy) were found to be associated with delayed reading skills (p > 0.05). Eye movements in

  15. Parallel processing using an optical delay-based reservoir computer

    Science.gov (United States)

    Van der Sande, Guy; Nguimdo, Romain Modeste; Verschaffelt, Guy

    2016-04-01

    Delay systems subject to delayed optical feedback have recently shown great potential in solving computationally hard tasks. By implementing a neuro-inspired computational scheme relying on the transient response to optical data injection, high processing speeds have been demonstrated. However, reservoir computing systems based on delay dynamics discussed in the literature are designed by coupling many different stand-alone components which lead to bulky, lack of long-term stability, non-monolithic systems. Here we numerically investigate the possibility of implementing reservoir computing schemes based on semiconductor ring lasers. Semiconductor ring lasers are semiconductor lasers where the laser cavity consists of a ring-shaped waveguide. SRLs are highly integrable and scalable, making them ideal candidates for key components in photonic integrated circuits. SRLs can generate light in two counterpropagating directions between which bistability has been demonstrated. We demonstrate that two independent machine learning tasks , even with different nature of inputs with different input data signals can be simultaneously computed using a single photonic nonlinear node relying on the parallelism offered by photonics. We illustrate the performance on simultaneous chaotic time series prediction and a classification of the Nonlinear Channel Equalization. We take advantage of different directional modes to process individual tasks. Each directional mode processes one individual task to mitigate possible crosstalk between the tasks. Our results indicate that prediction/classification with errors comparable to the state-of-the-art performance can be obtained even with noise despite the two tasks being computed simultaneously. We also find that a good performance is obtained for both tasks for a broad range of the parameters. The results are discussed in detail in [Nguimdo et al., IEEE Trans. Neural Netw. Learn. Syst. 26, pp. 3301-3307, 2015

  16. Regret Expression and Social Learning Increases Delay to Sexual Gratification.

    Directory of Open Access Journals (Sweden)

    Amanda J Quisenberry

    Full Text Available Modification and prevention of risky sexual behavior is important to individuals' health and public health policy. This study employed a novel sexual discounting task to elucidate the effects of social learning and regret expression on delay to sexual gratification in a behavioral task.Amazon Mechanical Turk Workers were assigned to hear one of three scenarios about a friend who engages in similar sexual behavior. The scenarios included a positive health consequence, a negative health consequence or a negative health consequence with the expression of regret. After reading one scenario, participants were asked to select from 60 images, those with whom they would have casual sex. Of the selected images, participants chose one image each for the person they most and least want to have sex with and person most and least likely to have a sexually transmitted infection. They then answered questions about engaging in unprotected sex now or waiting some delay for condom-protected sex in each partner condition.Results indicate that the negative health outcome scenario with regret expression resulted in delayed sexual gratification in the most attractive and least STI partner conditions, whereas in the least attractive and most STI partner conditions the negative health outcome with and without regret resulted in delayed sexual gratification.Results suggest that the sexual discounting task is a relevant laboratory measure and the framing of information to include regret expression may be relevant for prevention of risky sexual behavior.

  17. Behavioral and neural correlates of delay of gratification 40 years later

    OpenAIRE

    Casey, B.J.; Somerville, Leah H.; Gotlib, Ian H.; Ayduk, Ozlem; Franklin, Nicholas T; Mary K Askren; Jonides, John; Berman, Marc G.; Nicole L. Wilson; Teslovich, Theresa; Glover, Gary; Zayas, Vivian; Mischel, Walter; Shoda, Yuichi

    2011-01-01

    We examined the neural basis of self-regulation in individuals from a cohort of preschoolers who performed the delay-of-gratification task 4 decades ago. Nearly 60 individuals, now in their mid-forties, were tested on “hot” and “cool” versions of a go/nogo task to assess whether delay of gratification in childhood predicts impulse control abilities and sensitivity to alluring cues (happy faces). Individuals who were less able to delay gratification in preschool and consistently showed low sel...

  18. Synchronizing time delay systems using variable delay in coupling

    Energy Technology Data Exchange (ETDEWEB)

    Ambika, G., E-mail: g.ambika@iiserpune.ac.in [Indian Institute of Science Education and Research, Pune 411 021 (India); Amritkar, R.E., E-mail: amritkar@prl.res.in [Physical Research Laboratory, Ahmedabad 380 009 (India)

    2011-11-15

    Highlights: > Delay and anticipation in coupling function varies with system dynamics. > Delay or anticipation of the synchronized state is independent of system delay. > Stability analysis developed is quite general. > We demonstrate enhanced security in communication. > Generalized synchronization possible over a wide range of parameter mismatch. - Abstract: We present a mechanism for synchronizing time delay systems using one way coupling with a variable delay in coupling that is reset at finite intervals. We present the analysis of the error dynamics that helps to isolate regions of stability of the synchronized state in the parameter space of interest for single and multiple delays. We supplement this by numerical simulations in a standard time delay system like Mackey Glass system. This method has the advantage that it can be adjusted to be delay or anticipatory in synchronization with a time which is independent of the system delay. We demonstrate the use of this method in communication using the bi channel scheme. We show that since the synchronizing channel carries information from transmitter only at intervals of reset time, it is not susceptible to an easy reconstruction.

  19. Small delay approximation of stochastic delay differential equations

    Science.gov (United States)

    Guillouzic, Steve; L'heureux, Ivan; Longtin, André

    1999-04-01

    Delay differential equations evolve in an infinite-dimensional phase space. In this paper, we consider the effect of external fluctuations (noise) on delay differential equations involving one variable, thus leading to univariate stochastic delay differential equations (SDDE's). For small delays, a univariate nondelayed stochastic differential equation approximating such a SDDE is presented. Another approximation, complementary to the first, is also obtained using an average of the SDDE's drift term over the delayed dynamical variable, which defines a conditional average drift. This second approximation is characterized by the fact that the diffusion term is identical to that of the original SDDE. For small delays, our approach yields a steady-state probability density and a conditional average drift which are in close agreement with numerical simulations of the original SDDE. We illustrate this scheme with the delayed linear Langevin equation and a stochastic version of the delayed logistic equation. The technique can be used with any type of noise, and is easily generalized to multiple delays.

  20. Theory and numerics of vibrational resonance in Duffing oscillators with time-delayed feedback.

    Science.gov (United States)

    Jeevarathinam, C; Rajasekar, S; Sanjuán, M A F

    2011-06-01

    The influence of linear time-delayed feedback on vibrational resonance is investigated in underdamped and overdamped Duffing oscillators with double-well and single-well potentials driven by both low frequency and high frequency periodic forces. This task is performed through both theoretical approach and numerical simulation. Theoretically determined values of the amplitude of the high frequency force and the delay time at which resonance occurs are in very good agreement with the numerical simulation. A major consequence of time-delayed feedback is that it gives rise to a periodic or quasiperiodic pattern of vibrational resonance profile with respect to the time-delayed parameter. An appropriate time delay is shown to induce a resonance in an overdamped single-well system which is otherwise not possible. For a range of values of the time-delayed parameters, the response amplitude is found to be larger than in delay-time feedback-free systems.

  1. Delay tolerant networks

    CERN Document Server

    Gao, Longxiang; Luan, Tom H

    2015-01-01

    This brief presents emerging and promising communication methods for network reliability via delay tolerant networks (DTNs). Different from traditional networks, DTNs possess unique features, such as long latency and unstable network topology. As a result, DTNs can be widely applied to critical applications, such as space communications, disaster rescue, and battlefield communications. The brief provides a complete investigation of DTNs and their current applications, from an overview to the latest development in the area. The core issue of data forward in DTNs is tackled, including the importance of social characteristics, which is an essential feature if the mobile devices are used for human communication. Security and privacy issues in DTNs are discussed, and future work is also discussed.

  2. Looking for an Alternative.

    Science.gov (United States)

    Kennedy, Jack

    1999-01-01

    Argues that high school newspapers might do well to create stronger ties with alternative weeklies. Discusses issues of niche marketing, alternative content, and alternative presentation. Notes that high school papers could learn a lot from alternative newspapers. (SR)

  3. Inhibition of propofol on single neuron and neuronal ensemble activity in prefrontal cortex of rats during working memory task.

    Science.gov (United States)

    Xu, Xinyu; Tian, Yu; Wang, Guolin; Tian, Xin

    2014-08-15

    Working memory (WM) refers to the temporary storage and manipulation of information necessary for performance of complex cognitive tasks. There is a growing interest in whether and how propofol anesthesia inhibits WM function. The aim of this study is to investigate the possible inhibition mechanism of propofol anesthesia from the view of single neuron and neuronal ensemble activities. Adult SD rats were randomly divided into two groups: propofol group (0.9 mg kg(-1)min(-1), 2h via a tail vein catheter) and control group. All the rats were tested for working memory performances in a Y-maze-rewarded alternation task (a task of delayed non-matched-to-sample) at 24, 48, 72 h after propofol anesthesia, and the behavior results of WM tasks were recorded at the same time. Spatio-temporal trains of action potentials were obtained from the original signals. Single neuron activity was characterized by peri-event time histograms analysis and neuron ensemble activities were characterized by Granger causality to describe the interactions within the neuron ensemble. The results show that: comparing with the control group, the percentage of neurons excited and related to WM was significantly decreased (pneuron ensemble were significantly weakened (p0.05), which were consistent with the behavior results. These findings could lead to improved understanding of the mechanism of anesthesia inhibition on WM functions from the view of single neuron activity and neuron ensemble interactions.

  4. Three Approaches to Task-Based Syllabus Design.

    Science.gov (United States)

    Long, Michael H.; Crookes, Graham

    1992-01-01

    A variety of units (e.g., word, structure, notion, function, and situation) are used in synthetic syllabi, but task has recently appeared as the unit of analysis in three primarily analytic, Type B alternatives: procedural, process, and task syllabi. Descriptions and limitations of each are presented. (138 references) (Author/LB)

  5. Delay and probability discounting of sexual and monetary outcomes in individuals with cocaine use disorders and matched controls.

    Science.gov (United States)

    Johnson, Matthew W; Johnson, Patrick S; Herrmann, Evan S; Sweeney, Mary M

    2015-01-01

    Individuals with cocaine use disorders are disproportionately affected by HIV/AIDS, partly due to higher rates of unprotected sex. Recent research suggests delay discounting of condom use is a factor in sexual HIV risk. Delay discounting is a behavioral economic concept describing how delaying an event reduces that event's value or impact on behavior. Probability discounting is a related concept describing how the uncertainty of an event decreases its impact on behavior. Individuals with cocaine use disorders (n = 23) and matched non-cocaine-using controls (n = 24) were compared in decision-making tasks involving hypothetical outcomes: delay discounting of condom-protected sex (Sexual Delay Discounting Task), delay discounting of money, the effect of sexually transmitted infection (STI) risk on likelihood of condom use (Sexual Probability Discounting Task), and probability discounting of money. The Cocaine group discounted delayed condom-protected sex (i.e., were more likely to have unprotected sex vs. wait for a condom) significantly more than controls in two of four Sexual Delay Discounting Task partner conditions. The Cocaine group also discounted delayed money (i.e., preferred smaller immediate amounts over larger delayed amounts) significantly more than controls. In the Sexual Probability Discounting Task, both groups showed sensitivity to STI risk, however the groups did not differ. The Cocaine group did not consistently discount probabilistic money more or less than controls. Steeper discounting of delayed, but not probabilistic, sexual outcomes may contribute to greater rates of sexual HIV risk among individuals with cocaine use disorders. Probability discounting of sexual outcomes may contribute to risk of unprotected sex in both groups. Correlations showed sexual and monetary results were unrelated, for both delay and probability discounting. The results highlight the importance of studying specific behavioral processes (e.g., delay and probability

  6. On the Gravitomagnetic Time Delay

    OpenAIRE

    Ciufolini, I.; Kopeikin, S.; Mashhoon, B.; Ricci, F

    2002-01-01

    We study the gravitational time delay in ray propagation due to rotating masses in the linear approximation of general relativity. Simple expressions are given for the gravitomagnetic time delay that occurs when rays of radiation cross a slowly rotating shell and propagate in the field of a distant rotating source. Moreover, we calculate the local gravitational time delay in the Goedel universe. The observational consequences of these results in the case of weak gravitational lensing are disc...

  7. Demographic determinants of delayed divorce.

    Science.gov (United States)

    Chan, L Y; Heaton, T B

    1989-01-01

    This study identifies factors that predict delayed divorce in the US. The findings show that factors which influence marital stability in general also correlate with delayed divorce in the same direction. Wife's age at marriage, age of the youngest child, wife's religion, region of residence, and metropolitan residence have substantial effects of delayed divorce, but the effects of race, parental divorce, premarital pregnancy, and socioeconomic status are small.

  8. Location Estimation using Delayed Measurements

    DEFF Research Database (Denmark)

    Bak, Martin; Larsen, Thomas Dall; Nørgård, Peter Magnus

    1998-01-01

    When combining data from various sensors it is vital to acknowledge possible measurement delays. Furthermore, the sensor fusion algorithm, often a Kalman filter, should be modified in order to handle the delay. The paper examines different possibilities for handling delays and applies a new techn...... technique to a sensor fusion system for estimating the location of an autonomous guided vehicle. The system fuses encoder and vision measurements in an extended Kalman filter. Results from experiments in a real environment are reported...

  9. Delay-independent stability of genetic regulatory networks.

    Science.gov (United States)

    Wu, Fang-Xiang

    2011-11-01

    Genetic regulatory networks can be described by nonlinear differential equations with time delays. In this paper, we study both locally and globally delay-independent stability of genetic regulatory networks, taking messenger ribonucleic acid alternative splicing into consideration. Based on nonnegative matrix theory, we first develop necessary and sufficient conditions for locally delay-independent stability of genetic regulatory networks with multiple time delays. Compared to the previous results, these conditions are easy to verify. Then we develop sufficient conditions for global delay-independent stability for genetic regulatory networks. Compared to the previous results, this sufficient condition is less conservative. To illustrate theorems developed in this paper, we analyze delay-independent stability of two genetic regulatory networks: a real-life repressilatory network with three genes and three proteins, and a synthetic gene regulatory network with five genes and seven proteins. The simulation results show that the theorems developed in this paper can effectively determine the delay-independent stability of genetic regulatory networks.

  10. Concurrent Delay in Construction Disputes

    DEFF Research Database (Denmark)

    Cavaleri, Sylvie Cécile

    period of delay can potentially be attributed to several events falling within both parties' spheres of responsibility, commonly termed concurrent delay, is rarely regulated in construction contracts in spite of its common occurrence. This book analyses both the theoretical foundations and the practical......Delay is one of the issues most frequently encountered in today’s construction industry; it causes significant economic damage to all parties involved. Construction contracts, standard and bespoke, almost invariably consider delay from a perspective of single liability. If the event causing...

  11. Time Delay of CGM Sensors

    Science.gov (United States)

    Schmelzeisen-Redeker, Günther; Schoemaker, Michael; Kirchsteiger, Harald; Freckmann, Guido; Heinemann, Lutz; del Re, Luigi

    2015-01-01

    Background: Continuous glucose monitoring (CGM) is a powerful tool to support the optimization of glucose control of patients with diabetes. However, CGM systems measure glucose in interstitial fluid but not in blood. Rapid changes in one compartment are not accompanied by similar changes in the other, but follow with some delay. Such time delays hamper detection of, for example, hypoglycemic events. Our aim is to discuss the causes and extent of time delays and approaches to compensate for these. Methods: CGM data were obtained in a clinical study with 37 patients with a prototype glucose sensor. The study was divided into 5 phases over 2 years. In all, 8 patients participated in 2 phases separated by 8 months. A total number of 108 CGM data sets including raw signals were used for data analysis and were processed by statistical methods to obtain estimates of the time delay. Results: Overall mean (SD) time delay of the raw signals with respect to blood glucose was 9.5 (3.7) min, median was 9 min (interquartile range 4 min). Analysis of time delays observed in the same patients separated by 8 months suggests a patient dependent delay. No significant correlation was observed between delay and anamnestic or anthropometric data. The use of a prediction algorithm reduced the delay by 4 minutes on average. Conclusions: Prediction algorithms should be used to provide real-time CGM readings more consistent with simultaneous measurements by SMBG. Patient specificity may play an important role in improving prediction quality. PMID:26243773

  12. Concurrent Delay in Construction Disputes

    DEFF Research Database (Denmark)

    Cavaleri, Sylvie Cécile

    Delay is one of the issues most frequently encountered in today’s construction industry; it causes significant economic damage to all parties involved. Construction contracts, standard and bespoke, almost invariably consider delay from a perspective of single liability. If the event causing...... period of delay can potentially be attributed to several events falling within both parties' spheres of responsibility, commonly termed concurrent delay, is rarely regulated in construction contracts in spite of its common occurrence. This book analyses both the theoretical foundations and the practical...

  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. What Task Designers Do.

    Science.gov (United States)

    Johnson, Keith

    2000-01-01

    Describes a research project that is concerned with the design procedures followed by those engaged in designing pedagogic tasks for use in classrooms. Focuses on the part of the project that involves actual observation of designers in the process of developing one specific task for class use. Findings are presented under three headers: control…

  15. Task usefulness affects perception of rivalrous images.

    Science.gov (United States)

    Chopin, Adrien; Mamassian, Pascal

    2010-12-01

    In bistable perception, several interpretations of the same physical stimulus are perceived in alternation. If one interpretation appears to help the observer to be successful in an auxiliary task, will that interpretation be seen more often than the other? We addressed this question using rivalrous stimuli. One of the elicited percepts presented an advantage for a separate visual search task that was run in close temporal proximity to the rivalry task. We found that the percept that was useful for the search task became dominant over the alternate percept. Observers were not aware of the manipulation that made one percept more useful, which suggests that usefulness was learned implicitly. The learning influenced only the first percept of each rivalrous presentation, but the bias persisted even when the useful percept was no longer useful. The long-lasting aspect of the effect distinguishes it from other documented attentional effects on bistable perception. Therefore, using implicit learning, we demonstrated that task usefulness can durably change the appearance of a stimulus.

  16. Dissociations in the effect of delay on object recognition: evidence for an associative model of recognition memory.

    Science.gov (United States)

    Tam, Shu K E; Robinson, Jasper; Jennings, Dómhnall J; Bonardi, Charlotte

    2014-01-01

    Rats were administered 3 versions of an object recognition task: In the spontaneous object recognition task (SOR) animals discriminated between a familiar object and a novel object; in the temporal order task they discriminated between 2 familiar objects, 1 of which had been presented more recently than the other; and, in the object-in-place task, they discriminated among 4 previously presented objects, 2 of which were presented in the same locations as in preexposure and 2 in different but familiar locations. In each task animals were tested at 2 delays (5 min and 2 hr) between the sample and test phases in the SOR and object-in-place task, and between the 2 sample phases in the temporal order task. Performance in the SOR was poorer with the longer delay, whereas in the temporal order task performance improved with delay. There was no effect of delay on object-in-place performance. In addition the performance of animals with neurotoxic lesions of the dorsal hippocampus was selectively impaired in the object-in-place task at the longer delay. These findings are interpreted within the framework of Wagner's (1981) model of memory.

  17. Exchanging the liquidity hypothesis: Delay discounting of money and self-relevant non-money rewards.

    Science.gov (United States)

    Stuppy-Sullivan, Allison M; Tormohlen, Kayla N; Yi, Richard

    2016-01-01

    Evidence that primary rewards (e.g., food and drugs of abuse) are discounted more than money is frequently attributed to money's high degree of liquidity, or exchangeability for many commodities. The present study provides some evidence against this liquidity hypothesis by contrasting delay discounting of monetary rewards (liquid) and non-monetary commodities (non-liquid) that are self-relevant and utility-matched. Ninety-seven (97) undergraduate students initially completed a conventional binary-choice delay discounting of money task. Participants returned one week later and completed a self-relevant commodity delay discounting task. Both conventional hypothesis testing and more-conservative tests of statistical equivalence revealed correspondence in rate of delay discounting of money and self-relevant commodities, and in one magnitude condition, less discounting for the latter. The present results indicate that liquidity of money cannot fully account for the lower rate of delay discounting compared to non-money rewards.

  18. Comparison of Alternative Processes for Support Decisions

    Directory of Open Access Journals (Sweden)

    Manuel Martínez-Álvarez

    2014-08-01

    Full Text Available There are many tasks that revolve around combinatorial analysis problems, same tasks found in Decision Support Systems (DSS as most of these are responsible for assessing a number of possibilities to deliver the best options. Within the analysis of possible solutions is performed by the DSS there are alternative procedures inside the engine for making decisions that involve them. As part of these alternative procedures today has highlighted the use of metaheuristics, thus in this paper we propose a comparison of some of them trying to broaden the spectrum we have for the applications nowadays.

  19. Alternating hemiplegia of childhood.

    Science.gov (United States)

    Kansagra, Sujay; Mikati, Mohamad A; Vigevano, Federico

    2013-01-01

    Alternating hemiplegia of childhood (AHC) is a very rare disease characterized by recurrent attacks of loss of muscular tone resulting in hypomobility of one side of the body. The etiology of the disease due to ATP1A3 gene mutations in the majority of patients. Few familial cases have been described. AHC has an onset in the first few months of life. Hemiplegic episodes are often accompanied by other paroxysmal manifestations, such as lateral eyes and head deviation toward the hemiplegic side and a very peculiar monocular nystagmus. As the attack progresses, hemiplegia can shift to the other side of the body. Sometimes the attack can provoke bilateral paralysis, and these patients may have severe clinical impairment, with difficulty in swallowing and breathing. Hemiplegic attacks may be triggered by different stimuli, like bath in warm water, motor activity, or emotion. The frequency of attacks is high, usually several in a month or in a week. The duration is variable from a few minutes to several hours or even days. Sleep can stop the attack. Movement disorders such as dystonia and abnormal movements are frequent. Cognitive delay of variable degree is a common feature. Epilepsy has been reported in 50% of the cases, but seizure onset is usually during the third or fourth year of life. Many drugs have been used in AHC with very few results. Flunarizine has the most supportive anecdotal evidence regarding efficacy.

  20. Supporting complex search tasks

    DEFF Research Database (Denmark)

    Gäde, Maria; Hall, Mark; Huurdeman, Hugo

    2015-01-01

    There is broad consensus in the field of IR that search is complex in many use cases and applications, both on the Web and in domain specific collections, and both professionally and in our daily life. Yet our understanding of complex search tasks, in comparison to simple look up tasks, is fragme......There is broad consensus in the field of IR that search is complex in many use cases and applications, both on the Web and in domain specific collections, and both professionally and in our daily life. Yet our understanding of complex search tasks, in comparison to simple look up tasks......, and recommendations, and supporting exploratory search to sensemaking and analytics, UI and UX design pose an overconstrained challenge. How do we know that our approach is any good? Supporting complex search task requires new collaborations across the whole field of IR, and the proposed workshop will bring together...

  1. Supporting complex search tasks

    DEFF Research Database (Denmark)

    Gäde, Maria; Hall, Mark; Huurdeman, Hugo;

    2015-01-01

    There is broad consensus in the field of IR that search is complex in many use cases and applications, both on the Web and in domain specific collections, and both professionally and in our daily life. Yet our understanding of complex search tasks, in comparison to simple look up tasks......, 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...... introductory to specialized, and from authoritative to speculative or opinionated, when to show what sources of information? How does the information seeking process evolve and what are relevant differences between different stages? With complex task and search process management, blending searching, browsing...

  2. Synchronization in networks of mutually delay-coupled phase-locked loops

    Science.gov (United States)

    Pollakis, Alexandros; Wetzel, Lucas; Jörg, David J.; Rave, Wolfgang; Fettweis, Gerhard; Jülicher, Frank

    2014-11-01

    Electronic components that perform tasks in a concerted way rely on a common time reference. For instance, parallel computing demands synchronous clocking of multiple cores or processors to reliably carry out joint computations. Here, we show that mutually coupled phase-locked loops (PLLs) enable synchronous clocking in large-scale systems with transmission delays. We present a phase description of coupled PLLs that includes filter kernels and delayed signal transmission. We find that transmission delays in the coupling enable the existence of stable synchronized states, while instantaneously coupled PLLs do not tend to synchronize. We show how filtering and transmission delays govern the collective frequency and the time scale of synchronization.

  3. 45 CFR 74.91 - Alternative dispute resolution.

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 1 2010-10-01 2010-10-01 false Alternative dispute resolution. 74.91 Section 74... NONPROFIT ORGANIZATIONS, AND COMMERCIAL ORGANIZATIONS Disputes § 74.91 Alternative dispute resolution. HHS... resolution (ADR) techniques. ADR often is effective in reducing the cost, delay and contentiousness...

  4. Task-baseret kommunikativ sprogundervisning

    DEFF Research Database (Denmark)

    Pedersen, Michael Svendsen

    2015-01-01

    Definition af task-baseret sprogundervisning, kriterier for task. Forskning i Second Language Acquisition med brug af task, tilrettelæggelse af task-baseret kommunikativ undervisning. Begrænsninger i og perspektiver for videreudvikling af task-baseret sprogundervising-......Definition af task-baseret sprogundervisning, kriterier for task. Forskning i Second Language Acquisition med brug af task, tilrettelæggelse af task-baseret kommunikativ undervisning. Begrænsninger i og perspektiver for videreudvikling af task-baseret sprogundervising-...

  5. Age and educational track influence adolescent discounting of delayed rewards

    Directory of Open Access Journals (Sweden)

    Nikki Christina Lee

    2013-12-01

    Full Text Available This study examined age-related changes in a specific aspect of adolescent decision-making, namely the preference for future versus immediate outcomes. A sample of 622 Dutch adolescents aged 12 -17 years completed a temporal discounting task. Participants were asked to choose between a delayed reward of €50 or an immediate reward of lower value. The delay interval was varied in three blocks (1 week, 1 month, 6 months. Results showed that preferences for large delayed rewards over smaller immediate rewards increased with age: late adolescents made more long-term decisions than early adolescents. This change was related to educational track. In the lower educational track, an age-related decrease in discounting was found for all three delay intervals. In the higher educational track this decrease only occurred for the six month delay interval. However, across all delay intervals enrolment in a higher level educational track was associated with an increased preference for long-term rewards. These results suggest that late adolescents are less susceptible to the competing presence of an immediate reward when making long-term decisions, a skill which becomes increasingly important as they transition into adulthood.

  6. Delay discounting and future-directed thinking in anhedonic individuals.

    Science.gov (United States)

    Lempert, Karolina M; Pizzagalli, Diego A

    2010-09-01

    Anhedonia (lack of reactivity to pleasurable stimuli) and a negatively skewed view of the future are important components of depression that could affect economic decisions in depressed individuals. Delay discounting paradigms might be useful for probing putative affective and cognitive underpinnings of such decisions. As a first step to evaluate whether difficulties experiencing pleasure might affect delay discounting, 36 undergraduate students with varying levels of anhedonia performed a delay discounting task in which they made choices between a small immediate and larger future monetary reward. Increasing levels of anhedonia (Snaith-Hamilton Pleasure Scale) were negatively associated with delay discounting rate, indicating that anhedonic individuals tended to choose the larger, albeit delayed reward. These correlations remained after controlling for variables previously linked to delay discounting (working memory capacity and impulsivity) and pessimistic future-directed thinking. The current findings provide preliminary evidence indicating that anhedonic individuals make less myopic decisions about their future, possibly due to their decreased responsiveness to immediate rewards. (c) 2010 Elsevier Ltd. All rights reserved.

  7. Transparent concurrent execution of mutually exclusive alternatives

    OpenAIRE

    Smith, Jonathan M.; Gerald Q. Maguire Jr.

    1988-01-01

    We examine the task of concurrently computing alternative solutions to a problem. We restrict our interest to the case where only one of the solutions is needed; in this case we need some rule for selecting between the solutions. We use "fastest first," where the first successful alternative is selected. For problems where the required execution time is unpredictable, such as database queries. this method can show substantial execution time performance increases. These increases are dependent...

  8. Registration Delay and Student Performance

    Science.gov (United States)

    Siefken, Jason

    2017-01-01

    Tracking the difference between the time a first-year student is allowed to register for a course and the time he or she does register for a course (a student's registration delay), we notice a negative correlation between registration delay and final grade in a course. The difference between a student who registers within the first two minutes…

  9. 78 FR 59422 - Delayed Applications

    Science.gov (United States)

    2013-09-26

    ... Pipeline and Hazardous Materials Safety Administration Delayed Applications AGENCY: Office of Hazardous... applications delayed more than 180 days. SUMMARY: In accordance with the requirements of 49 U.S.C. 5117(c), PHMSA is publishing the following list of special permit applications that have been in process for 180...

  10. High resolution digital delay timer

    Science.gov (United States)

    Martin, Albert D.

    1988-01-01

    Method and apparatus are provided for generating an output pulse following a trigger pulse at a time delay interval preset with a resolution which is high relative to a low resolution available from supplied clock pulses. A first lumped constant delay (20) provides a first output signal (24) at predetermined interpolation intervals corresponding to the desired high resolution time interval. Latching circuits (26, 28) latch the high resolution data (24) to form a first synchronizing data set (60). A selected time interval has been preset to internal counters (142, 146, 154) and corrected for circuit propagation delay times having the same order of magnitude as the desired high resolution. Internal system clock pulses (32, 34) count down the counters to generate an internal pulse delayed by an interval which is functionally related to the preset time interval. A second LCD (184) corrects the internal signal with the high resolution time delay. A second internal pulse is then applied to a third LCD (74) to generate a second set of synchronizing data (76) which is complementary with the first set of synchronizing data (60) for presentation to logic circuits (64). The logic circuits (64) further delay the internal output signal (72) to obtain a proper phase relationship of an output signal (80) with the internal pulses (32, 34). The final delayed output signal (80) thereafter enables the output pulse generator (82) to produce the desired output pulse (84) at the preset time delay interval following input of the trigger pulse (10, 12).

  11. Calibrating for Ionospheric Phase Delays

    Science.gov (United States)

    Macdoran, P. F.

    1985-01-01

    Technique determines ionospheric phase delay on real-time universally applicable basis in terms of electrons per meter squared by coherently modulating two L-band carrier frequencies received from two Global Positioning System satelites. Two pseudorandom number sequences cross-correlated to derive delay time.

  12. #FakeNobelDelayReasons

    CERN Multimedia

    2013-01-01

    Tuesday’s hour-long delay of the Nobel Prize in Physics announcement was (and still is) quite the cause for speculation. But on the Twittersphere, it was simply the catalyst for some fantastic puns, so-bad-they're-good physics jokes and other shenanigans. Here are some of our favourite #FakeNobelDelayReasons.    

  13. Imitation dynamics with time delay.

    Science.gov (United States)

    Wang, Shi-Chang; Yu, Jie-Ru; Kurokawa, Shun; Tao, Yi

    2017-05-07

    Based on the classic imitation dynamics (Hofbauer and Sigmund, 1998, Evolutionary Games and Population Dynamics, Cambridge University Press), the imitation dynamics with time delay is investigated, where the probability that an individual will imitate its opponent's own strategy is assumed to depend on the comparison between the past expected payoff of this individual's own strategy and the past expected payoff of its opponent's own strategy, i.e. there is a time delay effect. For the two-phenotype model, we show that if the system has an interior equilibrium and this interior equilibrium is stable when there is no time delay, then there must be a critical value of time delay such that the system tends to a stable periodic solution when the time delay is larger than the critical value. On the other hand, for three-phenotype (rock-scissors-paper) model, the numerical analysis shows that for the stable periodic solution induced by the time delay, the amplitude and the period will increase with the increase of the time delay. These results should help to understand the evolution of behavior based on the imitation dynamics with time delay. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Preschoolers' Preparation for Retrieval in Object Relocation Tasks.

    Science.gov (United States)

    Beal, Carole R.; Fleisig, Wayne E.

    The finding that young children do not prepare markers to help themselves relocate objects after a delay may have resulted from children's misunderstanding of the difficulty of unassisted retrieval. This study examined children's ability to recognize that they should prepare markers in two simplified object relocation tasks after they had been…

  15. Time-delay damping theory

    Institute of Scientific and Technical Information of China (English)

    洪峰

    2002-01-01

    In this paper, existing damping theories are briefly reviewed. On the basis of the existing damping theories, a new kind of damping theory, i.e., the time-delay damping theory, is developed. In the time-delay damping theory, the damping force is considered to be directly proportional to the increment of displacement. The response analysis of an SDOF time-delay damping system is carried out, and the methods for obtaining the solution for a time-delay damping system in the time domain as well as the frequency domain are given. The comparison between results from different damping theories shows that the time-delay damping theory is both reasonable and convenient.

  16. Asynchronous Bounded Expected Delay Networks

    CERN Document Server

    Bakhshi, Rena; Fokkink, Wan; Pang, Jun

    2010-01-01

    The commonly used asynchronous bounded delay (ABD) network models assume a fixed bound on message delay. We propose a probabilistic network model, called asynchronous bounded expected delay (ABE) model. Instead of a strict bound, the ABE model requires only a bound on the expected message delay. While the conditions of ABD networks restrict the set of possible executions, in ABE networks all asynchronous executions are possible, but executions with extremely long delays are less probable. In contrast to ABD networks, ABE networks cannot be synchronised efficiently. At the example of an election algorithm, we show that the minimal assumptions of ABE networks are sufficient for the development of efficient algorithms. For anonymous, unidirectional ABE rings of known size N we devise a probabilistic leader election algorithm having average message and time complexity O(N).

  17. Delayed radiation neuropathy

    Energy Technology Data Exchange (ETDEWEB)

    Nagashima, T.; Miyamoto, K.; Beppu, H.; Hirose, K.; Yamada, K. (Tokyo Metropolitan Neurological Hospital (Japan))

    1981-07-01

    A case of cervical plexus neuropathy was reported in association with chronic radio-dermatitis, myxedema with thyroid adenoma and epiglottic tumor. A 38-year-old man has noticed muscle weakness and wasting of the right shoulder girdle since age 33. A detailed history taking revealed a previous irradiation to the neck because of the cervical lymphadenopathy at age 10 (X-ray 3,000 rads), keroid skin change at age 19, obesity and edema since 26, and hoarseness at 34. Laryngoscopic examination revealed a tumor on the right vocal cord, diagnosed as benign papilloma by histological study. In addition, there were chronic radio-dermatitis around the neck, primary hypothyroidism with a benign functioning adenoma on the right lobe of the thyroid, the right phrenic nerve palsy and the right recurrent nerve palsy. All these lesions were considered to be the late sequellae of radiation to the neck in childhood. Other neurological signs were weakness and amyotrophy of the right shoulder girdle with patchy sensory loss, and areflexia of the right arm. Gross power was fairly well preserved in the right hand. EMG showed neurogenic changes in the tested muscles, suggesting a peripheral nerve lesion. Nerve conduction velocities were normal. No abnormal findings were revealed by myelography and spinal CT. The neurological findings of the patient were compatible with the diagnosis of middle cervical plexus palsy apparently due to late radiation effect. In the literature eight cases of post-radiation neuropathy with a long latency have been reported. The present case with the longest latency after the radiation should be included in the series of the reported cases of ''delayed radiation neuropathy.'' (author).

  18. Delayed neutrons measurement at the MEGAPIE target

    Energy Technology Data Exchange (ETDEWEB)

    Panebianco, S.; Bokov, P.; Dore, D.; Letourneau, A.; Prevost, A.; Ridikas, D. [CEA Saclay, Dept. d' Astrophysique de Physique des Particules, de Physique Nucleaire et de l' Instrumentation Associee (DSM/DAPNIA/SPhN), 91- Gif sur Yvette (France); Ledoux, X. [CEA Bruyeres-le-Chatel (CEA DIF, DPTA/SPN), 91 (France). Dept. de Physique Theorique et Appliquee

    2008-07-01

    In the framework of the Neutronic and Nuclear Assessment Task Group of the MEGAPIE experiment we measured the delayed neutron (DN) flux at the top of the target. The measurement was proposed mainly for radioprotection purposes since the DN flux at the top of the target has been estimated to be of the same order of magnitude as the prompt neutron flux. Given the strong model-dependence of DN predictions, the measurement of DN contribution to the total neutron activity at the top of the target was thus desired. Moreover, this measurement is complementary to the DN experiments performed at PNPI (Gatchina) on solid lead and bismuth targets. The DN measurement at MEGAPIE was performed during the start-up phase of the target. In this paper we present a detailed description of the experimental setup and some preliminary results on decay spectra. (authors)

  19. Delayed neutrons measurement at the MEGAPIE target

    CERN Document Server

    Panebianco, Stefano; Dore, Diane; Ledoux, Xavier; Letourneau, Alain; Prevost, Aurelien; Ridikas, Danas

    2007-01-01

    In the framework of the Neutronic and Nuclear Assessment Task Group of the MEGAPIE experiment we measured the delayed neutron (DN) flux at the top of the target. The measurement was proposed mainly for radioprotection purposes since the DN flux at the top of the target has been estimated to be of the same order of magnitude as the prompt neutron flux. Given the strong model-dependence of DN predictions, the measurement of DN contribution to the total neutron activity at the top of the target was thus desired. Moreover, this measurement is complementary to the DN experiments performed at PNPI (Gatchina) on solid lead and bismuth targets. The DN measurement at MEGAPIE was performed during the start-up phase of the target. In this paper we present a detailed description of the experimental setup and some preliminary results on decay spectra.

  20. Duration reproduction with sensory feedback delay: Differential involvement of perception and action time

    Directory of Open Access Journals (Sweden)

    Stephanie eGanzenmüller

    2012-10-01

    Full Text Available Previous research has shown that voluntary action can attract subsequent, delayed feedback events towards the action, and adaptation to the sensorimotor delay can even reverse motor-sensory temporal-order judgments. However, whether and how sensorimotor delay affects duration reproduction is still unclear. To investigate this, we injected an onset- or offset-delay to the sensory feedback signal from a duration reproduction task. We compared duration reproductions within (visual, auditory modality and across audiovisual modalities with feedback signal onset- and offset-delay manipulations. We found that the reproduced duration was lengthened in both visual and auditory feedback signal onset-delay conditions. The lengthening effect was evident immediately, on the first trial with the onset delay. However, when the onset of the feedback signal was prior to the action, the lengthening effect was diminished. In contrast, a shortening effect was found with feedback signal offset-delay, though the effect was weaker and manifested only in the auditory offset-delay condition. These findings indicate that participants tend to mix the onset of action and the feedback signal more when the feedback is delayed, and they heavily rely on motor-stop signals for the duration reproduction. Furthermore, auditory duration was overestimated compared to visual duration in crossmodal feedback conditions, and the overestimation of auditory duration (or the underestimation of visual duration was independent of the delay manipulation.

  1. Energy Efficient Task Light

    DEFF Research Database (Denmark)

    Logadottir, Asta; Ardkapan, Siamak Rahimi; Johnsen, Kjeld

    2014-01-01

    The objectives of this work is to develop a task light for office lighting that fulfils the minimum requirements of the European standard EN12464 - 1 : Light and lighting – Lighting of work places, Part 1: Indoor workplaces and the Danish standard DS 700 : Lys og belysning I arbejdsrum , or more...... specifically the requirements that apply to the work area and the immediate surrounding area. By providing a task light that fulfils the requirements for task lighting and the immediate surrounding area, the general lighting only needs to provide the illuminance levels required for background lighting...... and thereby a reduction in installed power for general lighting of about 40 % compared to the way illuminance levels are designed in an office environment in Denmark today. This lighting strategy is useful when the placement of the task area is not defined in the space before the lighting is design ed...

  2. Organizing Core Tasks

    DEFF Research Database (Denmark)

    Boll, Karen

    Civil servants conduct the work which makes welfare states functions on an everyday bases: Police men police, school teachers teach, and tax inspectors inspect. Focus in this paper is on the core tasks of tax inspectors. The paper argues that their core task of securing the collection of revenue...... has remained much the same within the last 10 years. However, how the core task has been organized has changed considerable under the influence of various “organizing devices”. The paper focusses on how organizing devices such as risk assessment, output-focus, effect orientation, and treatment...... projects influence the organization of core tasks within the tax administration. The paper shows that the organizational transformations based on the use of these devices have had consequences both for the overall collection of revenue and for the employees’ feeling of “making a difference”. All in all...

  3. Delay Tolerance in Underwater Wireless Communications: A Routing Perspective

    Directory of Open Access Journals (Sweden)

    Safdar Hussain Bouk

    2016-01-01

    Full Text Available Similar to terrestrial networks, underwater wireless networks (UWNs also aid several critical tasks including coastal surveillance, underwater pollution detection, and other maritime applications. Currently, once underwater sensor nodes are deployed at different levels of the sea, it is nearly impossible or very expensive to reconfigure the hardware, for example, battery. Taking this issue into account, considerable amount of research has been carried out to ensure minimum energy costs and reliable communication between underwater nodes and base stations. As a result, several different network protocols were proposed for UWN, including MAC, PHY, transport, and routing. Recently, a new paradigm was introduced claiming that the intermittent nature of acoustic channel and signal resulted in designing delay tolerant routing schemes for the UWN, known as an underwater delay tolerant network. In this paper, we provide a comprehensive survey of underwater routing protocols with emphasis on the limitations, challenges, and future open issues in the context of delay tolerant network routing.

  4. Alternating between pro- and antisaccades: switch-costs manifest via decoupling the spatial relations between stimulus and response.

    Science.gov (United States)

    Heath, Matthew; Gillen, Caitlin; Samani, Ashna

    2016-03-01

    Antisaccades are a nonstandard task requiring a response mirror-symmetrical to the location of a target. The completion of an antisaccade has been shown to delay the reaction time (RT) of a subsequent prosaccade, whereas the converse switch elicits a null RT cost (i.e., the unidirectional prosaccade switch-cost). The present study sought to determine whether the prosaccade switch-cost arises from low-level interference specific to the sensory features of a target (i.e., modality-dependent) or manifests via the high-level demands of dissociating the spatial relations between stimulus and response (i.e., modality-independent). Participants alternated between pro- and antisaccades wherein the target associated with the response alternated between visual and auditory modalities. Thus, the present design involved task-switch (i.e., switching from a pro- to antisaccade and vice versa) and modality-switch (i.e., switching from a visual to auditory target and vice versa) trials as well as their task- and modality-repetition counterparts. RTs were longer for modality-switch than modality-repetition trials. Notably, however, modality-switch trials did not nullify or lessen the unidirectional prosaccade switch-cost; that is, the magnitude of the RT cost for task-switch prosaccades was equivalent across modality-switch and modality-repetition trials. Thus, competitive interference within a sensory modality does not contribute to the unidirectional prosaccade switch-cost. Instead, the modality-independent findings evince that dissociating the spatial relations between stimulus and response instantiates a high-level and inertially persistent nonstandard task-set that impedes the planning of a subsequent prosaccade.

  5. Neuroticism Delays Detection of Facial Expressions.

    Science.gov (United States)

    Sawada, Reiko; Sato, Wataru; Uono, Shota; Kochiyama, Takanori; Kubota, Yasutaka; Yoshimura, Sayaka; Toichi, Motomi

    2016-01-01

    The rapid detection of emotional signals from facial expressions is fundamental for human social interaction. The personality factor of neuroticism modulates the processing of various types of emotional facial expressions; however, its effect on the detection of emotional facial expressions remains unclear. In this study, participants with high- and low-neuroticism scores performed a visual search task to detect normal expressions of anger and happiness, and their anti-expressions within a crowd of neutral expressions. Anti-expressions contained an amount of visual changes equivalent to those found in normal expressions compared to neutral expressions, but they were usually recognized as neutral expressions. Subjective emotional ratings in response to each facial expression stimulus were also obtained. Participants with high-neuroticism showed an overall delay in the detection of target facial expressions compared to participants with low-neuroticism. Additionally, the high-neuroticism group showed higher levels of arousal to facial expressions compared to the low-neuroticism group. These data suggest that neuroticism modulates the detection of emotional facial expressions in healthy participants; high levels of neuroticism delay overall detection of facial expressions and enhance emotional arousal in response to facial expressions.

  6. Personal relative deprivation, delay discounting, and gambling.

    Science.gov (United States)

    Callan, Mitchell J; Shead, N Will; Olson, James M

    2011-11-01

    Several lines of research have provided evidence for a relation between personal relative deprivation and gambling. Despite this knowledge, little is known about possible psychological mechanisms through which personal relative deprivation exerts its influence on gambling. The authors of this research sought to examine one such mechanism: the desire for immediate rewards. Using complementary approaches to studying psychological mechanisms, they tested in four studies the general hypothesis that personal relative deprivation translates into gambling urges and behavior in part via increased desires for immediate, even if smaller, rewards. Study 1 showed that an experimental manipulation of personal relative deprivation increased participants' preferences for smaller-sooner over larger-later rewards during a delay-discounting task. Studies 2 and 3 showed that a decreased willingness to delay gratification led to increased gambling behavior. Study 4 showed that preferences for smaller-sooner over larger-later rewards statistically mediated the relation between self-reported personal relative deprivation and gambling urges among a community sample of gamblers. The implications and potential applications of these findings are discussed.

  7. Comparing Motor Skills in Autism Spectrum Individuals With and Without Speech Delay.

    Science.gov (United States)

    Barbeau, Elise B; Meilleur, Andrée-Anne S; Zeffiro, Thomas A; Mottron, Laurent

    2015-12-01

    Movement atypicalities in speed, coordination, posture, and gait have been observed across the autism spectrum (AS) and atypicalities in coordination are more commonly observed in AS individuals without delayed speech (DSM-IV Asperger) than in those with atypical or delayed speech onset. However, few studies have provided quantitative data to support these mostly clinical observations. Here, we compared perceptual and motor performance between 30 typically developing and AS individuals (21 with speech delay and 18 without speech delay) to examine the associations between limb movement control and atypical speech development. Groups were matched for age, intelligence, and sex. The experimental design included: an inspection time task, which measures visual processing speed; the Purdue Pegboard, which measures finger dexterity, bimanual performance, and hand-eye coordination; the Annett Peg Moving Task, which measures unimanual goal-directed arm movement; and a simple reaction time task. We used analysis of covariance to investigate group differences in task performance and linear regression models to explore potential associations between intelligence, language skills, simple reaction time, and visually guided movement performance. AS participants without speech delay performed slower than typical participants in the Purdue Pegboard subtests. AS participants without speech delay showed poorer bimanual coordination than those with speech delay. Visual processing speed was slightly faster in both AS groups than in the typical group. Altogether, these results suggest that AS individuals with and without speech delay differ in visually guided and visually triggered behavior and show that early language skills are associated with slower movement in simple and complex motor tasks.

  8. The Optimal Sequence of Production Orders, Taking into Account the Cost of Delays

    Directory of Open Access Journals (Sweden)

    Dylewski Robert

    2016-06-01

    Full Text Available In flexible manufacturing systems the most important element in determining the proper course of technological processes, transport and storage is the control and planning subsystem. The key planning task is to determine the optimal sequence of production orders. This paper proposes a new method of determining the optimal sequence of production orders in view of the sum of the costs related to the delayed execution of orders. It takes into account the different unit costs of delays of individual orders and the amount of allowable delays of orders involving no delay costs. The optimum sequence of orders, in the single-machine problem, in view of the sum of the costs of delays may be significantly different from the optimal order, taking into account the sum of delay times.

  9. Temporal Dynamics of the Interaction between Reward and Time Delay during Intertemporal Choice

    Science.gov (United States)

    Gui, Dan-Yang; Li, Jin-Zhen; Li, Xiaoli; Luo, Yue-jia

    2016-01-01

    Intertemporal choice involves the processes of valuation and choice. Choice is often the result of subjective valuation, in which reward is integrated with time delay. Here, using event-related potential (ERP) signals as temporal hallmarks, we aim to investigate temporal dynamics of how reward interacts with time delay during a delayed discounting task. We found that participants preferred immediate rewards when delayed rewards were small or over long-term delays. Our ERP results suggested that the P200 component reflected an initial valuation of reward and time delay, while the frontal N2 component correlated with individual choices of immediate option of rewards. The LPP component was modulated by the N2 component. These findings demonstrate that the N2 component is the key component in temporal dynamics of the interaction between reward and time valuation.

  10. Alternative medicine - pain relief

    Science.gov (United States)

    Alternative medicine refers to treatments that are used instead of conventional (standard) ones. If you use an alternative ... with conventional medicine or therapy, it is considered complementary therapy. There are many forms of alternative medicine. Acupuncture ...

  11. Learning monopolies with delayed feedback on price expectations

    Science.gov (United States)

    Matsumoto, Akio; Szidarovszky, Ferenc

    2015-11-01

    We call the intercept of the price function with the vertical axis the maximum price and the slope of the price function the marginal price. In this paper it is assumed that a monopolistic firm has full information about the marginal price and its own cost function but is uncertain on the maximum price. However, by repeated interaction with the market, the obtained price observations give a basis for an adaptive learning process of the maximum price. It is also assumed that the price observations have fixed delays, so the learning process can be described by a delayed differential equation. In the cases of one or two delays, the asymptotic behavior of the resulting dynamic process is examined, stability conditions are derived. Three main results are demonstrated in the two delay learning processes. First, it is possible to stabilize the equilibrium which is unstable in the one delay model. Second, complex dynamics involving chaos, which is impossible in the one delay model, can emerge. Third, alternations of stability and instability (i.e., stability switches) occur repeatedly.

  12. Time Delay in Molecular Photoionization

    CERN Document Server

    Hockett, P; Villeneuve, D M; Corkum, P B

    2015-01-01

    Time-delays in the photoionization of molecules are investigated. As compared to atomic ionization, the time-delays expected from molecular ionization present a much richer phenomenon, with a strong spatial dependence due to the anisotropic nature of the molecular scattering potential. We investigate this from a scattering theory perspective, and make use of molecular photoionization calculations to examine this effect in representative homonuclear and hetronuclear diatomic molecules, nitrogen and carbon monoxide. We present energy and angle-resolved maps of the Wigner delay time for single-photon valence ionization, and discuss the possibilities for experimental measurements.

  13. Behavioral and neural correlates of delay of gratification 40 years later.

    Science.gov (United States)

    Casey, B J; Somerville, Leah H; Gotlib, Ian H; Ayduk, Ozlem; Franklin, Nicholas T; Askren, Mary K; Jonides, John; Berman, Marc G; Wilson, Nicole L; Teslovich, Theresa; Glover, Gary; Zayas, Vivian; Mischel, Walter; Shoda, Yuichi

    2011-09-06

    We examined the neural basis of self-regulation in individuals from a cohort of preschoolers who performed the delay-of-gratification task 4 decades ago. Nearly 60 individuals, now in their mid-forties, were tested on "hot" and "cool" versions of a go/nogo task to assess whether delay of gratification in childhood predicts impulse control abilities and sensitivity to alluring cues (happy faces). Individuals who were less able to delay gratification in preschool and consistently showed low self-control abilities in their twenties and thirties performed more poorly than did high delayers when having to suppress a response to a happy face but not to a neutral or fearful face. This finding suggests that sensitivity to environmental hot cues plays a significant role in individuals' ability to suppress actions toward such stimuli. A subset of these participants (n = 26) underwent functional imaging for the first time to test for biased recruitment of frontostriatal circuitry when required to suppress responses to alluring cues. Whereas the prefrontal cortex differentiated between nogo and go trials to a greater extent in high delayers, the ventral striatum showed exaggerated recruitment in low delayers. Thus, resistance to temptation as measured originally by the delay-of-gratification task is a relatively stable individual difference that predicts reliable biases in frontostriatal circuitries that integrate motivational and control processes.

  14. Preschoolers’ Delay of Gratification Predicts Their Body Mass 30 Years Later

    Science.gov (United States)

    Schlam, Tanya R.; Wilson, Nicole L.; Shoda, Yuichi; Mischel, Walter; Ayduk, Ozlem

    2012-01-01

    Objective To assess whether preschoolers’ performance on a delay of gratification task would predict their body mass index (BMI) 30 years later. Study design In the late 1960s/early 1970s, 4-year-olds from a university-affiliated preschool completed the classic delay of gratification task. As part of a longitudinal study, a subset (N = 164, 57% women) completed a follow-up approximately 30 years later and self-reported their height and weight. Data were analyzed using hierarchical regression. Results Performance on the delay of gratification task accounted for a significant portion of variance in BMI (4%, p delayed gratification predicted a .2 point reduction in BMI in adulthood. Conclusions Delaying gratification longer at 4 years of age was associated with having a lower BMI three decades later. The study is, however, correlational, and it is therefore not possible to make causal inferences regarding the relation between delay duration and BMI. Identifying children with greater difficulty delaying gratification could help detect children at risk of becoming overweight or obese. Interventions that improve self-control in young children have been developed and might reduce children’s risk of becoming overweight while having positive effects on other outcomes important to society. PMID:22906511

  15. Preschoolers' delay of gratification predicts their body mass 30 years later.

    Science.gov (United States)

    Schlam, Tanya R; Wilson, Nicole L; Shoda, Yuichi; Mischel, Walter; Ayduk, Ozlem

    2013-01-01

    To assess whether preschoolers' performance on a delay of gratification task would predict their body mass index (BMI) 30 years later. In the late 1960s/early 1970s, 4-year-olds from a university-affiliated preschool completed the classic delay of gratification task. As part of a longitudinal study, a subset (n = 164; 57% women) were followed up approximately 30 years later and self-reported their height and weight. Data were analyzed using hierarchical regression. Performance on the delay of gratification task accounted for a significant portion of variance in BMI (4%; P delayed gratification predicted a 0.2-point reduction in BMI in adulthood. Longer delay of gratification at age 4 years was associated with a lower BMI 3 decades later. Because this study is correlational, it is not possible to make causal inferences regarding the relationship between delay duration and BMI. Identifying children with greater difficulty in delaying gratification could help detect children at risk of becoming overweight or obese. Interventions that improve self-control in young children have been developed and might reduce children's risk of becoming overweight and also have positive effects on other outcomes important to society. Copyright © 2013 Mosby, Inc. All rights reserved.

  16. Delayed feedback during sensorimotor learning selectively disrupts adaptation but not strategy use.

    Science.gov (United States)

    Brudner, Samuel N; Kethidi, Nikhit; Graeupner, Damaris; Ivry, Richard B; Taylor, Jordan A

    2016-03-01

    In sensorimotor adaptation tasks, feedback delays can cause significant reductions in the rate of learning. This constraint is puzzling given that many skilled behaviors have inherently long delays (e.g., hitting a golf ball). One difference in these task domains is that adaptation is primarily driven by error-based feedback, whereas skilled performance may also rely to a large extent on outcome-based feedback. This difference suggests that error- and outcome-based feedback may engage different learning processes, and these processes may be associated with different temporal constraints. We tested this hypothesis in a visuomotor adaptation task. Error feedback was indicated by the terminal position of a cursor, while outcome feedback was indicated by points. In separate groups of participants, the two feedback signals were presented immediately at the end of the movement, after a delay, or with just the error feedback delayed. Participants learned to counter the rotation in a similar manner regardless of feedback delay. However, the aftereffect, an indicator of implicit motor adaptation, was attenuated with delayed error feedback, consistent with the hypothesis that a different learning process supports performance under delay. We tested this by employing a task that dissociates the contribution of explicit strategies and implicit adaptation. We find that explicit aiming strategies contribute to the majority of the learning curve, regardless of delay; however, implicit learning, measured over the course of learning and by aftereffects, was significantly attenuated with delayed error-based feedback. These experiments offer new insight into the temporal constraints associated with different motor learning processes.

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

    Science.gov (United States)

    Lien, Mei-Ching; Ruthruff, Eric

    2004-01-01

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

  18. Leibniz Dynamics with Time Delay

    OpenAIRE

    Albu, I. D.; Opris, D.

    2005-01-01

    In this paper we show that several dynamical systems with time delay can be described as vector fields associated to smooth functions via a bracket of Leibniz structure. Some examples illustrate the theoretical considerations.

  19. Delays and networked control systems

    CERN Document Server

    Hetel, Laurentiu; Daafouz, Jamal; Johansson, Karl

    2016-01-01

    This edited monograph includes state-of-the-art contributions on continuous time dynamical networks with delays. The book is divided into four parts. The first part presents tools and methods for the analysis of time-delay systems with a particular attention on control problems of large scale or infinite-dimensional systems with delays. The second part of the book is dedicated to the use of time-delay models for the analysis and design of Networked Control Systems. The third part of the book focuses on the analysis and design of systems with asynchronous sampling intervals which occur in Networked Control Systems. The last part of the book exposes several contributions dealing with the design of cooperative control and observation laws for networked control systems. The target audience primarily comprises researchers and experts in the field of control theory, but the book may also be beneficial for graduate students. .

  20. A Kac CROW Delay Line

    CERN Document Server

    Sumetsky, M

    2013-01-01

    A low-loss CROW delay line with a weak inter-resonator coupling determined by the Kac matrix is dispersionless and can be easily impedance-matched by adjusting the coupling to the input/output waveguide.

  1. Do Adults Show an Effect of Delayed First Language Acquisition When Calculating Scalar Implicatures?

    Science.gov (United States)

    Davidson, Kathryn; Mayberry, Rachel I

    Language acquisition involves learning not only grammatical rules and a lexicon, but also what someone is intending to convey with their utterance: the semantic/pragmatic component of language. In this paper we separate the contributions of linguistic development and cognitive maturity to the acquisition of the semantic/pragmatic component of language by comparing deaf adults who had either early or late first exposure to their first language (ASL). We focus on the particular type of meaning at the semantic/pragmatic interface called scalar implicature, for which preschool-age children typically differ from adults. Children's behavior has been attributed to either their not knowing appropriate linguistic alternatives to consider or to cognitive developmental differences between children and adults. Unlike children, deaf adults with late language exposure are cognitively mature, although they never fully acquire some complex linguistic structures, and thus serve as a test for the role of language in such interpretations. Our results indicate an overall high performance by late learners, especially when implicatures are not based on conventionalized items. However, compared to early language learners, late language learners compute fewer implicatures when conventionalized linguistic alternatives are involved (e.g. ). We conclude that (i) in general, Gricean pragmatic reasoning does not seem to be impacted by delayed first language acquisition and can account for multiple quantity implicatures, but (ii) the creation of a scale based on lexical items can lead to ease in alternative creation that may be advantageously learned early in life, and that this may be one of several factors contributing to differences between adults and children on scalar implicature tasks.

  2. Impact of early or delayed elective resection in complicated diverticulitis

    Institute of Scientific and Technical Information of China (English)

    Kai Bachmann; Geeske Krause; Tamina Rawnaq; Lena Tomkotter; Yogesh Vashist; Shanly Shahmiri; Jakob R Izbicki; Maximilian Bockhorn

    2011-01-01

    AIM: To investigate the outcomes of early and delayed elective resection after initial antibiotic treatment in patients with complicated diverticulitis.METHODS: The study, a non-randomized comparison of the two approaches, included 421 consecutive patients who underwent surgical resection for complicated sigmoid diverticulitis (Hinchey classification Ⅰ-Ⅱ) at the Department of Surgery, University Medical Center Hamburg-Eppendorf between 2004 and 2009. The operating procedure, duration of hospital and intensive care unit stay, outcome, complications and socioeconomic costs were analyzed, with comparison made between the early and delayed elective resection strategies. RESULTS: The severity of the diverticulitis and American Society of Anesthesiologists score were comparable for the two groups. Patients who underwent delayed elective resection had a shorter hospital stay and operating time, and the rate of successfully completed laparoscopic resections was higher (80% vs 75%). Eight patients who were scheduled for delayed elective resection required urgent surgery because of complications of the diverticulitis, which resulted in a high rate of morbidity. Analysis of the socioeconomic effects showed that hospitalization costs were significantly higher for delayed elective resection compared with early elective resection (9296 € ± 694 € vs 8423 € ± 968 €; P = 0.001). Delayed elective resection showed a trend toward lower complications, and the operation appeared simpler to perform than early elective resection. Nevertheless, delayed elective resection carries a risk of complications occurring during the period of 6-8 wk that could necessitate an urgent resection with its consequent high morbidity, which counterbalanced many of the advantages. CONCLUSION: Overall, early elective resection for complicated, non-perforated diverticulitis is shown to be a suitable alternative to delayed elective resection after 6-8 wk, with additional beneficial socioeconomic

  3. Systematics in delayed neutron yields

    Energy Technology Data Exchange (ETDEWEB)

    Ohsawa, Takaaki [Kinki Univ., Higashi-Osaka, Osaka (Japan). Atomic Energy Research Inst.

    1998-03-01

    An attempt was made to reproduce the systematic trend observed in the delayed neutron yields for actinides on the basis of the five-Gaussian representation of the fission yield together with available data sets for delayed neutron emission probability. It was found that systematic decrease in DNY for heavier actinides is mainly due to decrease of fission yields of precursors in the lighter side of the light fragment region. (author)

  4. Time Delay in Molecular Photoionization

    OpenAIRE

    Hockett, P.; Frumker, E.; Villeneuve, D M; Corkum, P. B.

    2015-01-01

    Time-delays in the photoionization of molecules are investigated. As compared to atomic ionization, the time-delays expected from molecular ionization present a much richer phenomenon, with a strong spatial dependence due to the anisotropic nature of the molecular scattering potential. We investigate this from a scattering theory perspective, and make use of molecular photoionization calculations to examine this effect in representative homonuclear and hetronuclear diatomic molecules, nitroge...

  5. Measuring information-transfer delays.

    Directory of Open Access Journals (Sweden)

    Michael Wibral

    Full Text Available In complex networks such as gene networks, traffic systems or brain circuits it is important to understand how long it takes for the different parts of the network to effectively influence one another. In the brain, for example, axonal delays between brain areas can amount to several tens of milliseconds, adding an intrinsic component to any timing-based processing of information. Inferring neural interaction delays is thus needed to interpret the information transfer revealed by any analysis of directed interactions across brain structures. However, a robust estimation of interaction delays from neural activity faces several challenges if modeling assumptions on interaction mechanisms are wrong or cannot be made. Here, we propose a robust estimator for neuronal interaction delays rooted in an information-theoretic framework, which allows a model-free exploration of interactions. In particular, we extend transfer entropy to account for delayed source-target interactions, while crucially retaining the conditioning on the embedded target state at the immediately previous time step. We prove that this particular extension is indeed guaranteed to identify interaction delays between two coupled systems and is the only relevant option in keeping with Wiener's principle of causality. We demonstrate the performance of our approach in detecting interaction delays on finite data by numerical simulations of stochastic and deterministic processes, as well as on local field potential recordings. We also show the ability of the extended transfer entropy to detect the presence of multiple delays, as well as feedback loops. While evaluated on neuroscience data, we expect the estimator to be useful in other fields dealing with network dynamics.

  6. The Effect of a Constant Time Delay Procedure on Teaching an Adult with Severe Mental Retardation a Recreation Bowling Skill

    Science.gov (United States)

    Zhang, Jiabei; Cote, Bridget; Chen, Shihui; Liu, John

    2004-01-01

    The purpose of this study was to examine the effect of a constant time delay (CTD) procedure on teaching a recreational bowling skill to a 39-year-old male with severe mental retardation. The CTD procedure used 5 seconds as delay interval, task direction as target stimulus, physical assistance as controlling prompt, and oral praise as reinforcer.…

  7. Testing the Reliability of Delay Discounting of Ten Commodities Using the Fill-in-the-Blank Method

    Science.gov (United States)

    Weatherly, Jeffrey N.; Derenne, Adam; Terrell, Heather K.

    2011-01-01

    Several measures of delay discounting have been shown to be reliable over periods of up to 3 months. In the present study, 115 participants completed a fill-in-the-blank (FITB) delay-discounting task on sets of 5 different commodities, 12 weeks apart. Results showed that discounting rates were not well described by a hyperbolic function but were…

  8. The Effect of a Constant Time Delay Procedure on Teaching an Adult with Severe Mental Retardation a Recreation Bowling Skill

    Science.gov (United States)

    Zhang, Jiabei; Cote, Bridget; Chen, Shihui; Liu, John

    2004-01-01

    The purpose of this study was to examine the effect of a constant time delay (CTD) procedure on teaching a recreational bowling skill to a 39-year-old male with severe mental retardation. The CTD procedure used 5 seconds as delay interval, task direction as target stimulus, physical assistance as controlling prompt, and oral praise as reinforcer.…

  9. Effects on visual functions during tasks of object handling in virtual environment with a head mounted display.

    Science.gov (United States)

    Kawara, T; Ohmi, M; Yoshizawa, T

    1996-11-01

    This study examined the effects on visual functions of a prolonged handling task within the helmet-mounted display environment. Both version eye movement and accommodative response became gradually slower during the 40-min task. Although delayed presentation of display after head movement noticeably worsened both visual responses, presentation delay after hand movement did not significantly change the sluggishness of responses. Therefore it is suggested that decreasing time delay after head movement is a more important factor in order to improve human performance of handling tasks within the HMD environment.

  10. Basin stability in delayed dynamics

    Science.gov (United States)

    Leng, Siyang; Lin, Wei; Kurths, Jürgen

    2016-02-01

    Basin stability (BS) is a universal concept for complex systems studies, which focuses on the volume of the basin of attraction instead of the traditional linearization-based approach. It has a lot of applications in real-world systems especially in dynamical systems with a phenomenon of multi-stability, which is even more ubiquitous in delayed dynamics such as the firing neurons, the climatological processes, and the power grids. Due to the infinite dimensional property of the space for the initial values, how to properly define the basin’s volume for delayed dynamics remains a fundamental problem. We propose here a technique which projects the infinite dimensional initial state space to a finite-dimensional Euclidean space by expanding the initial function along with different orthogonal or nonorthogonal basis. A generalized concept of basin’s volume in delayed dynamics and a highly practicable calculating algorithm with a cross-validation procedure are provided to numerically estimate the basin of attraction in delayed dynamics. We show potential applicabilities of this approach by applying it to study several representative systems of biological or/and physical significance, including the delayed Hopfield neuronal model with multistability and delayed complex networks with synchronization dynamics.

  11. Does Presentation Order Impact Choice After Delay?

    Science.gov (United States)

    Berger, Jonah

    2016-07-01

    Options are often presented incidentally in a sequence, but does serial position impact choice after delay, and if so, how? We address this question in a consequential real-world choice domain. Using 25 years of citation data, and a unique identification strategy, we examine the relationship between article order (i.e., position in a journal issue) and citation count. Results indicate that mere serial position affects the prominence that research achieves: Earlier-listed articles receive more citations. Furthermore, our identification strategy allows us to cast doubt on alternative explanations (i.e., editorial placement) and instead indicate that the effect is driven by psychological processes of attention and memory. These findings deepen the understanding of how presentation order impacts choice, suggest that subtle presentation factors can bias an important scientific metric, and shed light on how psychological processes shape collective outcomes.

  12. Board Task Performance

    DEFF Research Database (Denmark)

    Minichilli, Alessandro; Zattoni, Alessandro; Nielsen, Sabina

    2012-01-01

    This paper addresses recent calls to narrow the micro–macro gap in management research (Bamberger, 2008), by incorporating a macro-level context variable (country) in exploring micro-level determinants of board effectiveness. Following the integrated model proposed by Forbes and Milliken (1999), we...... 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...... influence board tasks, and how the context moderates the relationship between processes and tasks. Our hypotheses are tested on a survey-based dataset of 535 medium-sized and large industrial firms in Italy and Norway, which are considered to substantially differ along legal and cultural dimensions...

  13. An approach to constitutional delay of growth and puberty

    Directory of Open Access Journals (Sweden)

    Ashraf T Soliman

    2012-01-01

    Full Text Available Constitutional delay of growth and puberty is a transient state of hypogonadotropic hypogonadism associated with prolongation of childhood phase of growth, delayed skeletal maturation, delayed and attenuated pubertal growth spurt, and relatively low insulin-like growth factor-1 secretion. In a considerable number of cases, the final adult height (Ht does not reach the mid-parental or the predicted adult Ht for the individual, with some degree of disproportionately short trunk. In the pre-pubertal male, testosterone (T replacement therapy can be used to induce pubertal development, accelerate growth and relieve the psychosocial complaints of the adolescents. However, some issues in the management are still unresolved. These include type, optimal timing, dose and duration of sex steroid treatment and the possible use of adjunctive or alternate therapy including: oxandrolone, aromatase inhibitors and human growth hormone.

  14. What are task-sets: a single, integrated representation or a collection of multiple control representations?

    Directory of Open Access Journals (Sweden)

    Dragan eRangelov

    2013-09-01

    Full Text Available Performing two randomly alternating tasks typically results in higher reaction times (RTs following a task switch, relative to a task repetition. These task switch costs (TSC reflect processes of switching between control settings for different tasks. The present study investigated whether task sets operate as a single, integrated representation or as an agglomeration of relatively independent components. In a cued task switch paradigm, target detection (present/absent and discrimination (blue/green/right-/left-tilted tasks alternated randomly across trials. The target was either a color or an orientation singleton among homogeneous distractors. Across two trials, the task and target-defining dimension repeated or changed randomly. For task switch trials, agglomerated task sets predict a difference between dimension changes and repetitions: joint task and dimension switches require full task set reconfiguration, while dimension repetitions permit re-using some control settings from the previous trial. By contrast, integrated task sets always require full switches, predicting dimension repetition effects (DREs to be absent across task switches. RT analyses showed significant DREs across task switches as well as repetitions supporting the notion of agglomerated task sets. Additionally, two event-related potentials (ERP were analyzed: the Posterior-Contralateral-Negativity (PCN indexing spatial selection dynamics, and the Sustained-Posterior-Contralateral-Negativity (SPCN indexing post-selective perceptual/semantic analysis. Significant DREs across task switches were observed for both the PCN and SPCN components. Together, DREs across task switches for RTs and two functionally distinct ERP components suggest that re-using control settings across different tasks is possible. The results thus support the ‘agglomerated-task-set’ hypothesis, and are inconsistent with ‘integrated task sets’.

  15. Goal orientation, perceived task outcome and task demands in mathematics tasks: effects on students' attitude in actual task settings.

    Science.gov (United States)

    Seegers, Gerard; van Putten, Cornelis M; de Brabander, Cornelis J

    2002-09-01

    In earlier studies, it has been found that students' domain-specific cognitions and personal learning goals (goal orientation) influence task-specific appraisals of actual learning tasks. The relations between domain-specific and task-specific variables have been specified in the model of adaptive learning. In this study, additional influences, i.e., perceived task outcome on a former occasion and variations in task demands, were investigated. The purpose of this study was to identify personality and situational variables that mediate students' attitude when confronted with a mathematics task. Students worked on a mathematics task in two subsequent sessions. Effects of perceived task outcome at the first session on students' attitude at the second session were investigated. In addition, we investigated how differences in task demands influenced students' attitude. Variations in task demands were provoked by different conditions in task-instruction. In one condition, students were told that the result on the test would add to their mark on mathematics. This outcome orienting condition was contrasted with a task-orienting condition where students were told that the results on the test would not be used to give individual grades. Participants were sixth grade students (N = 345; aged 11-12 years) from 14 primary schools. Multivariate and univariate analyses of (co)variance were applied to the data. Independent variables were goal orientation, task demands, and perceived task outcome, with task-specific variables (estimated competence for the task, task attraction, task relevance, and willingness to invest effort) as the dependent variables. The results showed that previous perceived task outcome had a substantial impact on students' attitude. Additional but smaller effects were found for variation in task demands. Furthermore, effects of previous perceived task outcome and task demands were related to goal orientation. The resulting pattern confirmed that, in general

  16. From Fixed Points to Chaos: Three Models of Delayed Discrimination

    Science.gov (United States)

    Barak, Omri; Sussillo, David; Romo, Ranulfo; Tsodyks, Misha; Abbott, L.F.

    2013-01-01

    Working memory is a crucial component of most cognitive tasks. Its neuronal mechanisms are still unclear despite intensive experimental and theoretical explorations. Most theoretical models of working memory assume both time-invariant neural representations and precise connectivity schemes based on the tuning properties of network neurons. A different, more recent class of models assumes randomly connected neurons that have no tuning to any particular task, and bases task performance purely on adjustment of network readout. Intermediate between these schemes are networks that start out random but are trained by a learning scheme. Experimental studies of a delayed vibrotactile discrimination task indicate that some of the neurons in prefrontal cortex are persistently tuned to the frequency of a remembered stimulus, but the majority exhibit more complex relationships to the stimulus that vary considerably across time. We compare three models, ranging from a highly organized linear attractor model to a randomly connected network with chaotic activity, with data recorded during this task. The random network does a surprisingly good job of both performing the task and matching certain aspects of the data. The intermediate model, in which an initially random network is partially trained to perform the working memory task by tuning its recurrent and readout connections, provides a better description, although none of the models matches all features of the data. Our results suggest that prefrontal networks may begin in a random state relative to the task and initially rely on modified readout for task performance. With further training, however, more tuned neurons with less time-varying responses should emerge as the networks become more structured. PMID:23438479

  17. Effect of fixation tasks on multifocal visual evoked potentials.

    Science.gov (United States)

    Martins, Alessandra; Klistorner, Alexander; Graham, Stuart; Billson, Frank

    2005-10-01

    This study investigated the effects of cognitive influence on the multifocal visual evoked potential (mVEP) at different levels of eccentricity. Three different foveal fixation conditions were utilized involving varying levels of task complexity. A more complex visual fixation task has been known to suppress peripheral signals in subjective testing. Twenty normal subjects had monocular mVEPs recorded using the AccuMap objective perimeter. This allowed simultaneous stimulation of 58 segments of the visual field to an eccentricity of 24 degrees. The mVEP was recorded using three different fixation conditions in random order. During task 1 the subject passively viewed the central fixation area. For task 2 alternating numbers were displayed within the fixation area; the subject on viewing the number '3' in the central fixation area indicated recognition by pressing a button. Throughout task 3, numbers were displayed as in task 2. The subject had the cognitive task of summating all the numbers. Analysis revealed that the increased attention and concentration demanded by tasks 2 and 3 in comparison with task 1 resulted in significantly enhanced central amplitudes of 9.41% (Mann-Whitney P = 0.0002) and 13.45% (P = 0.0002), respectively. These amplitudes became reduced in the periphery and approached those of task 1, resulting in no significant difference between the three tasks. Latencies demonstrated no significant difference between each task nor at any eccentricity (P > 0.05). As the complexity of each task increased the amount of alpha rhythm was significantly reduced. Our findings indicate that task 1 required a minimal demand of cognition and was associated with the greatest amount of alpha rhythm. It was also the most difficult to perform because of loss of interest. The other two tasks required a greater demand of higher order cognitive skills resulting in significantly enhanced amplitudes centrally and the attenuation of alpha rhythm. Therefore, amplitudes are

  18. All About Alternatives

    Science.gov (United States)

    Barr, Robert D.; And Others

    1972-01-01

    A primer on alternative schools. Described are existing programs in different areas, philosophy of the alternative schools, funding, student behavior, community relations, accountability, State regulations, management, and the environment of the alternative school. A list of sources of additional information on alternative schools is included.…

  19. Algebra task & drill sheets

    CERN Document Server

    Reed, Nat

    2011-01-01

    For grades 6-8, our State Standards-based combined resource meets the algebraic concepts addressed by the NCTM standards and encourages the students to review the concepts in unique ways. The task sheets introduce the mathematical concepts to the students around a central problem taken from real-life experiences, while the drill sheets provide warm-up and timed practice questions for the students to strengthen their procedural proficiency skills. Included are opportunities for problem-solving, patterning, algebraic graphing, equations and determining averages. The combined task & drill sheets

  20. Algebra task & drill sheets

    CERN Document Server

    Reed, Nat

    2011-01-01

    For grades 3-5, our State Standards-based combined resource meets the algebraic concepts addressed by the NCTM standards and encourages the students to review the concepts in unique ways. The task sheets introduce the mathematical concepts to the students around a central problem taken from real-life experiences, while the drill sheets provide warm-up and timed practice questions for the students to strengthen their procedural proficiency skills. Included are opportunities for problem-solving, patterning, algebraic graphing, equations and determining averages. The combined task & drill sheets

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

    Science.gov (United States)

    Murphy, Jacky

    2003-01-01

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

  2. Attentional switches and dual-task interference.

    Directory of Open Access Journals (Sweden)

    Janne F Ettwig

    Full Text Available In four experiments, we studied the time course of interference between detection of an oddball orientation target (OT in an 8-item circular search display, and identification of a letter target (LT in a central stream of distractor letters. Dual-task performance for different temporal lags between targets was compared to single-task performance. When the LT preceded the OT, dual-task performance levels were reduced at short inter-target intervals of 0 and 166 ms; when the OT preceded the LT, the dual-task interference was unexpectedly stronger and lasted for up to 500 ms. Resource competition due to temporally overlapping target processing cannot account for this result, because the feature search task is easier than the letter identification task, and therefore would have generated less interference when presented first. Two alternative explanations were explored. First, by manipulating the spatial inter-target distance, we investigated to what degree there is a penalty associated with directing the attentional window from a large object (the search display to a smaller object (the central letter stream. Second, by varying the duration of the OT and subsequent mask, we studied whether the interference was caused by the difficulty of disengaging attention from the search display. Results support this second explanation and thus indicate that switching attention to the letter stream is hampered by the continuing presence of (masked search display items. This result shows that attentional effects may play a major role in dual-task execution and can easily obscure interference due to other factors such as resource competition.

  3. Delay Independent Criterion for Multiple Time-delay Systems

    Science.gov (United States)

    Chang, C. J.; Liu, K. F. R.; Yeh, K.; Chen, C. W.; Chung, P. Y.

    Based on the fuzzy Lyapunov method, this work addresses the stability conditions for nonlinear systems with multiple time delays to ensure the stability of building structure control systems. The delay independent conditions are derived via the traditional Lyapunov and fuzzy Lyapunov methods for multiple time-delay systems as approximated by the Tagagi-Sugeno (T-S) fuzzy model. The fuzzy Lyapunov function is defined as a fuzzy blending of quadratic Lyapunov functions. A parallel distributed compensation (PDC) scheme is utilized to construct a global fuzzy logic control (FLC) by blending all linear local state feedback controllers in the controller design procedure. Furthermore, the H infinity performance and robustness of the design for modeling errors also need to be considered in the stability conditions.

  4. Hubble Constant, Lensing, and Time Delay in Relativistic MOND

    OpenAIRE

    2012-01-01

    Time delay in galaxy gravitational lensing systems has been used to determine the value of Hubble constant. As in other dynamical phenomena at the scale of galaxy, dark matter is often invoked in gravitational lensing to account for the "missing mass" (the apparent discrepancy between the dynamical mass and the luminous mass). Alternatively, modified gravity can be used to explain the discrepancy. In this paper we adopt the Tensor-Vector-Scalar gravity (TeVeS), a relativistic version of MOdif...

  5. A Daunting Task Still

    Institute of Scientific and Technical Information of China (English)

    ZHANG ZHIPING

    2010-01-01

    @@ Despite steady economic growth for three decades, China is still a developing country facing daunting poverty alleviation tasks. According to the poverty line of 1,196 yuan ($176) per capita net income in a year set in March 2009, the country still has a poverty population of more than 40 million, mainly living in rural areas.

  6. Task 1 quarternary tectonics

    Energy Technology Data Exchange (ETDEWEB)

    Bell, J.W.

    1994-12-31

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

  7. Communication Delays Impact Behavior and Performance Aboard the International Space Station.

    Science.gov (United States)

    Kintz, Natalie M; Palinkas, Lawrence A

    Long-duration space explorations will involve significant communication delays that will likely impact individual and team outcomes. However, the extent of these impacts and the appropriate countermeasures for their mitigation remain largely unknown. This study examined the feasibility and acceptability of utilizing the International Space Station (ISS) as a research platform to assess the impacts of communication delays on individual and team behavior and performance. For this study, 3 ISS crewmembers and 18 mission support personnel performed 10 tasks identified by subject matter experts as meeting study criteria, 6 tasks without a delay in communication and 4 tasks with a 50-s one-way delay. Assessments of individual and team performance and behavior were obtained after each task. The completion rate of posttask assessments and postmission interviews with astronauts were used to assess feasibility and acceptability. Posttask assessments were completed in 100% of the instances where a crewmember was assigned to a task and in 83% where mission support personnel were involved. Qualitative analysis of postmission interviews found the study to be important and acceptable to the three astronauts. However, they also reported the study was limited in the number and type of tasks included, limitations in survey questions, and preference for open-ended to scaled items. Although the ISS is considered a high fidelity analog for long-duration space missions, future studies of communication delays on the ISS must take into considerations the constraints imposed by mission operations and subject preferences and priorities. Kintz KM, Palinkas LA. Communication delays impact behavior and performance aboard the International Space Station. Aerosp Med Hum Perform. 2017; 87(11):940-946.

  8. Can tasks be inherently boring?

    Science.gov (United States)

    Charney, Evan

    2013-12-01

    Kurzban et al. argue that the experiences of "effort," "boredom," and "fatigue" are indications that the costs of a task outweigh its benefits. Reducing the costs of tasks to "opportunity costs" has the effect of rendering tasks costless and of denying that they can be inherently boring or tedious, something that "vigilance tasks" were intentionally designed to be.

  9. Estimation of contrast agent bolus arrival delays for improved reproducibility of liver DCE MRI

    Science.gov (United States)

    Chouhan, Manil D.; Bainbridge, Alan; Atkinson, David; Punwani, Shonit; Mookerjee, Rajeshwar P.; Lythgoe, Mark F.; Taylor, Stuart A.

    2016-10-01

    Delays between contrast agent (CA) arrival at the site of vascular input function (VIF) sampling and the tissue of interest affect dynamic contrast enhanced (DCE) MRI pharmacokinetic modelling. We investigate effects of altering VIF CA bolus arrival delays on liver DCE MRI perfusion parameters, propose an alternative approach to estimating delays and evaluate reproducibility. Thirteen healthy volunteers (28.7  ±  1.9 years, seven males) underwent liver DCE MRI using dual-input single compartment modelling, with reproducibility (n  =  9) measured at 7 days. Effects of VIF CA bolus arrival delays were assessed for arterial and portal venous input functions. Delays were pre-estimated using linear regression, with restricted free modelling around the pre-estimated delay. Perfusion parameters and 7 days reproducibility were compared using this method, freely modelled delays and no delays using one-way ANOVA. Reproducibility was assessed using Bland-Altman analysis of agreement. Maximum percent change relative to parameters obtained using zero delays, were  -31% for portal venous (PV) perfusion, +43% for total liver blood flow (TLBF), +3247% for hepatic arterial (HA) fraction, +150% for mean transit time and  -10% for distribution volume. Differences were demonstrated between the 3 methods for PV perfusion (p  =  0.0085) and HA fraction (p  liver DCE MRI quantification. Pre-estimation of delays with constrained free modelling improved 7 days reproducibility of perfusion parameters in volunteers.

  10. Impact of communication delays to and from the International Space Station on self-reported individual and team behavior and performance: A mixed-methods study

    Science.gov (United States)

    Kintz, Natalie M.; Chou, Chih-Ping; Vessey, William B.; Leveton, Lauren B.; Palinkas, Lawrence A.

    2016-12-01

    Deep space explorations will involve significant delays in communication to and from Earth that will likely impact individual and team outcomes. However, the extent of these impacts and the appropriate countermeasures for their mitigation remain largely unknown. This study utilized the International Space Station (ISS), a high-fidelity analog for deep space, as a research platform to assess the impact of communication delays on individual and team performance, mood, and behavior. Three astronauts on the ISS and 18 mission support personnel performed tasks with and without communication delays (50-s one-way) during a mission lasting 166 days. Self-reported assessments of individual and team performance and mood were obtained after each task. Secondary outcomes included communication quality and task autonomy. Qualitative data from post-mission interviews with astronauts were used to validate and expand on quantitative data, and to elicit recommendations for countermeasures. Crew well-being and communication quality were significantly reduced in communication delay tasks compared to control. Communication delays were also significantly associated with increased individual stress/frustration. Qualitative data suggest communication delays impacted operational outcomes (i.e. task efficiency), teamwork processes (i.e. team/task coordination) and mood (i.e. stress/frustration), particularly when tasks involved high task-related communication demands, either because of poor communication strategies or low crew autonomy. Training, teamwork, and technology-focused countermeasures were identified to mitigate or prevent adverse impacts.

  11. 49 CFR 236.563 - Delay time.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Delay time. 236.563 Section 236.563 Transportation... Cab Signal Systems Rules and Instructions; Locomotives § 236.563 Delay time. Delay time of automatic... requirements of § 236.24 shall take into consideration the delay time....

  12. Stochastic modelling of train delays and delay propagation in stations

    NARCIS (Netherlands)

    Yuan, J.

    2006-01-01

    A trade-off exists between efficiently utilizing the capacity of railway networks and improving the reliability and punctuality of train operations. This dissertation presents a new analytical probability model based on blocking time theory which estimates the knock-on delays of trains caused by

  13. A Comparative Study of Task-based vs. Task- supported Teaching Approaches in an EFL Context

    Directory of Open Access Journals (Sweden)

    Mahdieh Shafipoor

    2015-09-01

    Full Text Available In spite of the numerous merits of task-based language instruction as claimed by its supporters in the last few decades, task-supported teaching approach as an alternative was introduced. Since then, there have been controversial debates over the superiority of each of these two approaches. Thus, in the current research project, the purpose was to consider these two teaching approaches in the scope of English language teaching, with the purpose of exploring the most efficient one in an Iranian EFL context. To this end, 120 sophomore students, majoring in English language translation course at Islamic Azad University, Shar-e-Qods branch were selected among 4 intact reading comprehension II classes. Next, they were divided into two experimental groups. The first experimental group received task-based instruction and for the second experimental group, task-trusted teaching approach was applied. The results of the data analyses turned out that task-trusted teaching approach was superior to task-based teaching in teaching reading to EFL learners.

  14. Delaying vortex breakdown by waves

    Science.gov (United States)

    Yao, M. F.; Jiang, L. B.; Wu, J. Z.; Ma, H. Y.; Pan, J. Y.

    1989-03-01

    The effect of spiral waves on delaying vortex breakdown in a tube is studied experimentally and theoretically. When a harmonic oscillation was imposed on one of guiding vanes in the tube, the breakdown was observed to be postponed appreciately. According to the generalized Lagrangian mean theory, proper forcing spiral waves may produce an additional streaming momentum, of which the effect is favorable and similar to an axial suction at downstream end. The delayed breakdown position is further predicted by using nonlinear wave theory. Qualitative agreement between theory and experiment is obtained, and experimental comparison of the effects due to forcing spiral wave and axial suction is made.

  15. Delay equations and radiation damping

    Science.gov (United States)

    Chicone, C.; Kopeikin, S. M.; Mashhoon, B.; Retzloff, D. G.

    2001-06-01

    Starting from delay equations that model field retardation effects, we study the origin of runaway modes that appear in the solutions of the classical equations of motion involving the radiation reaction force. When retardation effects are small, we argue that the physically significant solutions belong to the so-called slow manifold of the system and we identify this invariant manifold with the attractor in the state space of the delay equation. We demonstrate via an example that when retardation effects are no longer small, the motion could exhibit bifurcation phenomena that are not contained in the local equations of motion.

  16. Time-domain nature of group delay

    Institute of Scientific and Technical Information of China (English)

    王建武; 冯正和

    2015-01-01

    The characteristic of group delay is analyzed based on an electronic circuit, and its time-domain nature is studied with time-domain simulation and experiment. The time-domain simulations and experimental results show that group delay is the delay of the energy center of the amplitude-modulated pulse, rather than the propagation delay of the electromagnetic field. As group velocity originates from the definition of group delay and group delay is different from the propagation delay, the superluminality or negativity of group velocity does not mean the superluminal or negative propagation of the electromagnetic field.

  17. Effects of Reliability and Global Context on Explicit and Implicit Measures of Sensed Hand Position in Cursor-Control Tasks

    Science.gov (United States)

    Rand, Miya K.; Heuer, Herbert

    2016-01-01

    In a cursor-control task in which the motion of the cursor is rotated randomly relative to the movement of the hand, the sensed directions of hand and cursor are mutually biased. In our previous study, we used implicit and explicit measures of the bias of sensed hand direction toward the direction of the cursor and found different characteristics. The present study serves to explore further differences and commonalities of these measures. In Experiment 1, we examined the effects of different relative reliabilities of visual and proprioceptive information on the explicitly and implicitly assessed bias of sensed hand direction. In two conditions, participants made an aiming movement and returned to the start position immediately or after a delay of 6 s during which the cursor was no longer visible. The unimodal proprioceptive information on final hand position in the delayed condition served to increase its relative reliability. As a result, the bias of sensed hand direction toward the direction of the cursor was reduced for the explicit measure, with a complementary increase of the bias of sensed cursor direction, but unchanged for the implicit measure. In Experiment 2, we examined the influence of global context, specifically of the across-trial sequence of judgments of hand and cursor direction. Both explicitly and implicitly assessed biases of sensed hand direction did not significantly differ between the alternated condition (trial-to-trial alternations of judgments of hand and cursor direction) and the blocked condition (judgments of hand or cursor directions in all trials). They both substantially decreased from the alternated to the randomized condition (random sequence of judgments of hand and cursor direction), without a complementary increase of the bias of sensed cursor direction. We conclude that our explicit and implicit measures are equally sensitive to variations of coupling strength as induced by the variation of global context in Experiment 2, but

  18. Delay discounting as a function of intrinsic/extrinsic religiousness, religious fundamentalism, and regular church attendance.

    Science.gov (United States)

    Weatherly, Jeffrey N; Plumm, Karyn M

    2012-01-01

    Delay discounting occurs when the subjective value of an outcome decreases because its delivery is delayed. Previous research has suggested that the rate at which some, but not all, outcomes are discounted varies as a function of regular church attendance. In the present study, 509 participants completed measures of intrinsic religiousness, extrinsic religiousness, religious fundamentalism, and whether they regularly attended church services. They then completed a delay-discounting task involving five outcomes. Although religiousness was not a significant predictor of discounting for all outcomes, participants scoring high in intrinsic religiousness tended to display less delay discounting than participants scoring low. Likewise, participants scoring high in religious fundamentalism tended to display more delay discounting than participants scoring low. These results partially replicate previous ones in showing that the process of discounting may vary as a function of religiousness. The results also provide some direction for those interested in altering how individuals discount.

  19. Synchronization of Switched Neural Networks With Communication Delays via the Event-Triggered Control.

    Science.gov (United States)

    Wen, Shiping; Zeng, Zhigang; Chen, Michael Z Q; Huang, Tingwen

    2017-10-01

    This paper addresses the issue of synchronization of switched delayed neural networks with communication delays via event-triggered control. For synchronizing coupled switched neural networks, we propose a novel event-triggered control law which could greatly reduce the number of control updates for synchronization tasks of coupled switched neural networks involving embedded microprocessors with limited on-board resources. The control signals are driven by properly defined events, which depend on the measurement errors and current-sampled states. By using a delay system method, a novel model of synchronization error system with delays is proposed with the communication delays and event-triggered control in the unified framework for coupled switched neural networks. The criteria are derived for the event-triggered synchronization analysis and control synthesis of switched neural networks via the Lyapunov-Krasovskii functional method and free weighting matrix approach. A numerical example is elaborated on to illustrate the effectiveness of the derived results.

  20. Performing Task Integration

    DEFF Research Database (Denmark)

    Elkjaer, Bente; Nickelsen, Niels Christian Mossfeldt

    . Here cross-professional coordination of work was done by scheduled communication twice a day. When we proposed a way for further integration of tasks through an all-inclusive team organization, we were met with resistance. We use the study to discuss whether relational coordination theory is able to do......In the paper, we deal with how to organize work for cross-professional knowledge sharing. We do so inspired by relational coordination theory, which is affiliated with positive organizational scholarship. Relational coordination theory is constituted by a combination of relationships marked...... away with differences regarding task definitions and working conditions as well as professional knowledge hierarchies and responsibilities for parts and wholes....

  1. Evaluating the economy of alternative energies to petroleum

    Energy Technology Data Exchange (ETDEWEB)

    Mitate, H.

    1982-01-01

    An account is given of the present state of the use of alternative energies to petroleum. This is followed by descriptions of current economic evaluations of such energies (energy choice and economy, cost analysis of alternative energy use) and of future tasks for economic evaluations (international comparisons of energy prices, comprehensive evaluations of alternative energies and economic evaluations of new energy technologies.) (1 ref.) (In Japanese)

  2. Delay and Disruption Tolerant Networking MACHETE Model

    Science.gov (United States)

    Segui, John S.; Jennings, Esther H.; Gao, Jay L.

    2011-01-01

    To verify satisfaction of communication requirements imposed by unique missions, as early as 2000, the Communications Networking Group at the Jet Propulsion Laboratory (JPL) saw the need for an environment to support interplanetary communication protocol design, validation, and characterization. JPL's Multi-mission Advanced Communications Hybrid Environment for Test and Evaluation (MACHETE), described in Simulator of Space Communication Networks (NPO-41373) NASA Tech Briefs, Vol. 29, No. 8 (August 2005), p. 44, combines various commercial, non-commercial, and in-house custom tools for simulation and performance analysis of space networks. The MACHETE environment supports orbital analysis, link budget analysis, communications network simulations, and hardware-in-the-loop testing. As NASA is expanding its Space Communications and Navigation (SCaN) capabilities to support planned and future missions, building infrastructure to maintain services and developing enabling technologies, an important and broader role is seen for MACHETE in design-phase evaluation of future SCaN architectures. To support evaluation of the developing Delay Tolerant Networking (DTN) field and its applicability for space networks, JPL developed MACHETE models for DTN Bundle Protocol (BP) and Licklider/Long-haul Transmission Protocol (LTP). DTN is an Internet Research Task Force (IRTF) architecture providing communication in and/or through highly stressed networking environments such as space exploration and battlefield networks. Stressed networking environments include those with intermittent (predictable and unknown) connectivity, large and/or variable delays, and high bit error rates. To provide its services over existing domain specific protocols, the DTN protocols reside at the application layer of the TCP/IP stack, forming a store-and-forward overlay network. The key capabilities of the Bundle Protocol include custody-based reliability, the ability to cope with intermittent connectivity

  3. Features or tasks?

    DEFF Research Database (Denmark)

    Heilesen, Simon

    In this paper for the Workshop on Human-computer interaction and e-learning, NordiCHI 2002, the author argues that in developing innovative E-learning systems, especially if constructivist pedagogy is to be applied, it will be useful to model the user interface on the often complex tasks...... that the user has to perform rather than just focusing on technical features (and adapting system use to them)....

  4. Impact of size and delay on neural activity in the rat limbic corticostriatal system

    Directory of Open Access Journals (Sweden)

    Matthew R Roesch

    2011-12-01

    Full Text Available A number of factors influence an animal’s economic decisions. Two most commonly studied are the magnitude of and delay to reward. To investigate how these factors are represented in the firing rates of single neurons, we devised a behavioral task that independently manipulated the expected delay to and size of reward. Rats perceived the differently delayed and sized rewards as having different values and were more motivated under short-delay and big-reward conditions than under long-delay and small-reward conditions as measured by percent choice, accuracy and reaction time. Since the creation of this task, we have recorded from several different brain areas including, orbitofrontal cortex, striatum, amygdala, substantia nigra pars reticulata, and midbrain dopamine neurons. Here, we review and compare those data with a substantial focus on those areas that have been shown to be critical for performance on classic time discounting procedures and provide a potential mechanism by which they might interact when animals are deciding between differently delayed rewards. We found that most brain areas in the cortico-limbic circuit encode both the magnitude and delay to reward delivery in one form or another, but only a few encode them together at the single neuron level.

  5. Impact of Size and Delay on Neural Activity in the Rat Limbic Corticostriatal System

    Science.gov (United States)

    Roesch, Matthew R.; Bryden, Daniel W.

    2011-01-01

    A number of factors influence an animal’s economic decisions. Two most commonly studied are the magnitude of and delay to reward. To investigate how these factors are represented in the firing rates of single neurons, we devised a behavioral task that independently manipulated the expected delay to and size of reward. Rats perceived the differently delayed and sized rewards as having different values and were more motivated under short delay and big-reward conditions than under long delay and small reward conditions as measured by percent choice, accuracy, and reaction time. Since the creation of this task, we have recorded from several different brain areas including, orbitofrontal cortex, striatum, amygdala, substantia nigra pars reticulata, and midbrain dopamine neurons. Here, we review and compare those data with a substantial focus on those areas that have been shown to be critical for performance on classic time discounting procedures and provide a potential mechanism by which they might interact when animals are deciding between differently delayed rewards. We found that most brain areas in the cortico-limbic circuit encode both the magnitude and delay to reward delivery in one form or another, but only a few encode them together at the single neuron level. PMID:22363252

  6. Impact of size and delay on neural activity in the rat limbic corticostriatal system.

    Science.gov (United States)

    Roesch, Matthew R; Bryden, Daniel W

    2011-01-01

    A number of factors influence an animal's economic decisions. Two most commonly studied are the magnitude of and delay to reward. To investigate how these factors are represented in the firing rates of single neurons, we devised a behavioral task that independently manipulated the expected delay to and size of reward. Rats perceived the differently delayed and sized rewards as having different values and were more motivated under short delay and big-reward conditions than under long delay and small reward conditions as measured by percent choice, accuracy, and reaction time. Since the creation of this task, we have recorded from several different brain areas including, orbitofrontal cortex, striatum, amygdala, substantia nigra pars reticulata, and midbrain dopamine neurons. Here, we review and compare those data with a substantial focus on those areas that have been shown to be critical for performance on classic time discounting procedures and provide a potential mechanism by which they might interact when animals are deciding between differently delayed rewards. We found that most brain areas in the cortico-limbic circuit encode both the magnitude and delay to reward delivery in one form or another, but only a few encode them together at the single neuron level.

  7. Individual differences in delay discounting under acute stress: the role of trait perceived stress

    Directory of Open Access Journals (Sweden)

    Karolina M. Lempert

    2012-07-01

    Full Text Available Delay discounting refers to the reduction of the value of a future reward as the delay to that reward increases. The rate at which individuals discount future rewards varies as a function of both individual and contextual differences, and high delay discounting rates have been linked with problematic behaviors, including drug abuse and gambling. The current study investigated the effects of acute anticipatory stress on delay discounting, while considering two important factors: individual perceptions of stress and whether the stressful situation is future-focused or present-focused. Half of the participants experienced acute stress by anticipating giving a videotaped speech. This stress was either future-oriented (speech about future job or present-oriented (speech about physical appearance. They then performed a delay discounting task, in which they chose between smaller, immediate rewards and larger, delayed rewards. Their scores on the Perceived Stress Scale were also collected. The way in which one appraises a stressful situation interacts with acute stress to influence choices; under stressful conditions, delay discounting rate was highest in individuals with low perceived stress and lowest for individuals with high perceived stress. This result might be related to individual variation in reward responsiveness under stress. Furthermore, the time orientation of the task interacted with its stressfulness to affect the individual’s propensity to choose immediate rewards. These findings add to our understanding of the intermediary factors between stress and decision making.

  8. Gap Task Force

    CERN Multimedia

    Lissuaer, D

    One of the more congested areas in the ATLAS detector is the GAP region (the area between the Barrel Calorimeter and the End Cap calorimeter) where Inner Detector services, LAr Services and some Tile services all must co-habitat in a very limited area. It has been clear for some time that the space in the GAP region is not sufficient to accommodate all that is needed. In the last few month additional problems of routing all the services to Z=0 have been encountered due to the very limited space between the Tile Calorimeter and the first layer of Muon chambers. The Technical Management Board (TMB) and the Executive Board (EB) decided in the middle of March to establish a Task Force to look at this problem and come up with a solution within well-specified guidelines. The task force consisted of experts from the ID, Muon, Liquid Argon and Tile systems in addition to experts from the Technical Coordination team and the Physics coordinator. The task force held many meetings and in general there were some very l...

  9. Mobile Thread Task Manager

    Science.gov (United States)

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

    2013-01-01

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

  10. Vowel alternations in English

    OpenAIRE

    Kazumi, Yukiko

    1992-01-01

    The purpose of this study is to investigate the nature of vowel alternations observed in English. What we call vowel alternations here consists of shortening and lengthening triggered by Level I affixation: ...

  11. The acquisition of grade alternation in North Saami

    Directory of Open Access Journals (Sweden)

    Berit Anne Bals

    2005-02-01

    Full Text Available This paper looks at how the North Saami grade alternation system develops in children. Grade alternation is a morphophonological process, in which foot-medial consonants alternate between two forms, the strong and the weak grade. There are qualitative alternations, quantitative alternations and in some patterns, both the length and quality of the consonants alternate. These alternations happen in the declension of nouns and the conjugation of verbs. Some case forms of nouns and some forms of verbs are connected to the strong grade, whereas others are connected to the weak grade.The task with which children are faced, is to learn all the different phonological alternations and to connect them to morphology. This paper focuses on the order of acquisition of the various patterns, and on the types of mistakes that children make. We show that the type of alternations to be acquired first are quantity alternations, in which the length of the consonants alternates. The next patterns to be acquired are qualitative alternations, such as devoicing. In the third stage, children learn to combine qualitative and quantitative alternations, such as in deglottalization with nasal legthening. The last patterns to be acquired are patterns with complex foot medial consonants or consonant clusters. The article argues that children´s errors are purely phonological. Connecting the alternations to morphology happens early in the development, and that the remaining errors have to do with the complexity of the phonological alternation.

  12. Diagnostic Delay in Rheumatoid Arthritis

    DEFF Research Database (Denmark)

    Mølbaek, Karen; Hørslev-Petersen, Kim; Primdahl, Jette

    2016-01-01

    BACKGROUND: To prevent joint damage among patients with rheumatoid arthritis (RA), there is a need to minimize delays from the onset of symptoms until the initiation of appropriate therapy. The present study explored the factors that have an impact on the time it takes for Danish patients with RA...

  13. Livermore blasted for project delay

    CERN Multimedia

    1999-01-01

    In a 12 page report issued last week, a review committee set up by the University of California has concluded that mismanagement and poor planning are to blame for significant cost overruns and delays in the construction of NIF, the worlds largest laser (1 page).

  14. Providing delay guarantees in Bluetooth

    NARCIS (Netherlands)

    Ait Yaiz, R.; Heijenk, Gerhard J.; Titsworth, F.

    2003-01-01

    Bluetooth polling, also referred to as Bluetooth MAC scheduling or intra-piconet scheduling, is the mechanism that schedules the traffic between the participants in a Bluetooth network. Hence, this mechanism is highly determining with respect to the delay packets experience in a Bluetooth network.

  15. Deconstructing delayed posttraumatic stress disorder

    NARCIS (Netherlands)

    Smid, G.E.

    2011-01-01

    According to the Diagnostic and Statistical Manual of Mental Disorders, delayed posttraumatic stress disorder (PTSD) must be diagnosed in individuals fulfilling criteria for PTSD if the onset of symptoms is at least six months after the trauma. The purpose of this thesis was to establish the prevale

  16. Advanced optical delay line demonstrator

    NARCIS (Netherlands)

    Dool, T.C. van den; Kamphues, F.G.; Fouss, B.; Henrioulle, K.; Hogenhuis, H.

    2004-01-01

    TNO TPD, in cooperation with Micromega-Dynamics and Dutch Space, has designed an advanced Optical Delay Line (ODL) for use in future ground based and space interferometry missions. The work is performed under NIVR contract in preparation for GENIE and DARWIN. Using the ESO PRIMA DDL requirements as

  17. Providing Delay Guarantees in Bluetooth

    NARCIS (Netherlands)

    Ait Yaiz, Rachid; Heijenk, Geert; Titsworth, F.

    2003-01-01

    Bluetooth polling, also referred to as Bluetooth MAC scheduling or intra-piconet scheduling, is the mechanism that schedules the traffic between the participants in a Bluetooth network. Hence, this mechanism is highly determining with respect to the delay packets experience in a Bluetooth network. I

  18. Time Delay Circuits: A Quality Criterion for Delay Variations versus Frequency

    NARCIS (Netherlands)

    Garakoui, Seyed Kasra; Klumperink, Eric A.M.; Nauta, Bram; Vliet, van Frank E.

    2010-01-01

    This paper shows that the group delay of a delay circuit does not give sufficient information to predict the delay vs. frequency. A new criterion (fϕ=0) is proposed that characterizes the delay variations over a specified frequency range. The mathematical derivation of fϕ=0 for a single delay block

  19. THE ALL-DELAY STABILITY OF DEGENERATE DIFFERENTIAL SYSTEMS WITH DELAY

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In this paper,the all-delay stability of degenerate differential systems with delay is discussed.We come up with some new criteria for evaluating the all-delay stability of degenerate differential systems with delay and degenerate neutral differential systems with delay.Also,we give an example to illustrate the main results.

  20. Task Dominance Determines Backward Inhibition in Task Switching

    Directory of Open Access Journals (Sweden)

    Kerstin Jost

    2017-05-01

    Full Text Available Switching between tasks is assumed to be accompanied by inhibiting currently irrelevant, but competing tasks. A dominant task that strongly interferes with performing a weaker task may receive especially strong inhibition. We tested this prediction by letting participants switch among three tasks that differ in dominance: a location discrimination task with strong stimulus–response bindings (responding with left-hand and right-hand button presses to stimuli presented left or right to the fixation cross was combined with a color/pattern and a shape discrimination task, for which stimulus–response mappings were arbitrary (e.g., left-hand button press mapped to a red stimulus. Across three experiments, the dominance of the location task was documented by faster and more accurate responses than in the other tasks. This even held for incompatible stimulus–response mappings (i.e., right-hand response to a left-presented stimulus and vice versa, indicating that set-level compatibility (i.e., “dimension overlap” was sufficient for making this location task dominant. As a behavioral marker for backward inhibition, we utilized n-2 repetition costs that are defined by higher reaction times for a switch back to a just abandoned and thus just inhibited task (ABA sequence than for a switch to a less recently inhibited task (CBA, n-2 non-repetition. Reliable n-2 task repetition costs were obtained for all three tasks. Importantly, these costs were largest for the location task, suggesting that inhibition indeed was stronger for the dominant task. This finding adds to other evidence that the amount of inhibition is adjusted in a context-sensitive way.

  1. Systematic Task Allocation Evaluation in Distributed Software Development

    Science.gov (United States)

    Münch, Jürgen; Lamersdorf, Ansgar

    Systematic task allocation to different development sites in global software development projects can open business and engineering perspectives and help to reduce risks and problems inherent in distributed development. Relying only on a single evaluation criterion such as development cost when distributing tasks to development sites has shown to be very risky and often does not lead to successful solutions in the long run. Task allocation in global software projects is challenging due to a multitude of impact factors and constraints. Systematic allocation decisions require the ability to evaluate and compare task allocation alternatives and to effectively establish customized task allocation practices in an organization. In this article, we present a customizable process for task allocation evaluation that is based on results from a systematic interview study with practitioners. In this process, the relevant criteria for evaluating task allocation alternatives are derived by applying principles from goal-oriented measurement. In addition, the customization of the process is demonstrated, related work and limitations are sketched, and an outlook on future work is given.

  2. Spatial task context makes short-latency reaches prone to induced Roelofs illusion

    Directory of Open Access Journals (Sweden)

    Bahareh eTaghizadeh

    2014-08-01

    Full Text Available The perceptual localization of an object is often more prone to illusions than an immediate visuomotor action towards that object. The induced Roelofs effect (IRE probes the illusory influence of task-irrelevant visual contextual stimuli on the processing of task-relevant visuospatial instructions during movement preparation. In the IRE, the position of a task-irrelevant visual object induces a shift in the localization of a visual target when subjects indicate the position of the target by verbal response, key-presses or delayed pointing to the target (‘perception’ tasks, but not when immediately pointing or reaching towards it without instructed delay (‘action’ tasks. This discrepancy was taken as evidence for the dual-visual-stream or perception-action hypothesis, but was later explained by a phasic distortion of the egocentric spatial reference frame which is centered on subjective straight-ahead and used for reach planning. Both explanations critically depend on delayed movements to explain the IRE for action tasks. Here we ask: first, if the IRE can be observed for short-latency reaches; second, if the IRE in fact depends on a distorted egocentric frame of reference. Human subjects were tested in new versions of the IRE task in which the reach goal had to be localized with respect to another object, i.e., in an allocentric reference frame. First, we found an IRE even for immediate reaches in our allocentric task, but not for an otherwise similar egocentric control task. Second, the IRE depended on the position of the task-irrelevant frame relative to the reference object, not relative to subjective straight-ahead. We conclude that the IRE for reaching does not mandatorily depend on prolonged response delays, nor does it depend on motor planning in an egocentric reference frame. Instead, allocentric encoding of a movement goal is sufficient to make immediate reaches susceptible to IRE, underlining the context dependence of

  3. Calorimetry Task Force Report

    CERN Document Server

    Abdullin, Salavat; Banerjee, Sunanda; Beauceron, Stephanie; Beaudette, Florian; Bhatti, Anwar; Chlebana, Frank; Cossutti, Fabio; Hirschauer, James; Ivanchenko, V; Jang, Dong Wook; Jun, Soon Yung; Kunori, Shuichi; Kroeger, Rob; Liu, Yanwen; Moeller, Anthony; Paulini, Manfred; Piperov, Stefan; Rahmat, Rahmat; Rovelli, Chiara; Safronov, Grigory; Sharma, Seema; Spiropulu, Maria; Yetkin, Taylan

    2010-01-01

    In this note we summarize the progress made by the calorimeter simulation task force (CaloTF) over the past year. The CaloTF was established in February 2008 in order to understand and reconcile the discrepancies observed between the CMS calorimetry simulation and test beam data recorded during 2004 and 2006. The simulation has been significantly improved by using a newer version of Geant4 and an improved physics list for the full CMS detector simulation. Simulation times have been reduced by introducing flexible parameterizations to describe showering in the calorimeter (using a Gflash-like approach) which have been tuned to the test beam data.

  4. Quarternary tectonics, Task 1

    Energy Technology Data Exchange (ETDEWEB)

    Bell, J.W.

    1993-09-30

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

  5. Pair Negotiation When Developing English Speaking Tasks

    Directory of Open Access Journals (Sweden)

    Ingrid Liliana Bohórquez Suárez

    2011-12-01

    Full Text Available This study analyzes what characterizes the negotiations of seventh graders at a public school in Bogotá when working in pairs to develop speaking tasks in EFL classes. The inquiry is a descriptive case study that follows the qualitative paradigm. As a result of analyzing the data, we obtained four consecutive steps that characterize students’ negotiations: Establishing a connection with a partner to work with, proposing practical alternatives, refusing mates’ propositions, and making practical decisions. Moreover, we found that the constant performance of the process of negotiation provokes students to construct a sociolinguistic identity that allows agreements to emerge.

  6. Choice between delayed food and immediate opioids in rats: treatment effects and individual differences.

    Science.gov (United States)

    Panlilio, Leigh V; Secci, Maria E; Schindler, Charles W; Bradberry, Charles W

    2017-09-04

    Addiction involves maladaptive choice behavior in which immediate drug effects are valued more than delayed nondrug rewards. To model this behavior and extend our earlier work with the prescription opioid oxycodone, we allowed rats to choose between immediate intravenous delivery of the short-acting opioid remifentanil and delayed delivery of highly palatable food pellets. Treatment drugs were tested on a baseline where remifentanil was preferred over food. Treatment with a high dose of the opioid antagonist naltrexone decreased but did not reverse the preference for remifentanil. Treatment with the serotonin 5-HT2C agonist lorcaserin decreased remifentanil and food self-administration nonselectively. Across conditions in which the alternative to delayed food was either a moderate dose of oxycodone, a moderate or high dose of remifentanil, a smaller more immediate delivery of food, or timeout with no primary reinforcement, choice was determined by both the length of the delay and the nature of the alternative option. Delayed food was discounted most steeply when the alternative was a high dose of remifentanil, which was preferred over food when food was delayed by 30 s or more. Within-subject comparisons showed no evidence for trait-like impulsivity or sensitivity to delay across these conditions. Choice was determined more by the current contingencies of reinforcement than by innate individual differences. This finding suggests that people might develop steep delay-discounting functions because of the contingencies in their environment, and it supports the use of contingency management to enhance the relative value of delayed nondrug reinforcers.

  7. TASK ALLOCATION IN GEO-DISTRIBUTATED CYBER-PHYSICAL SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    Aggarwal, Rachel; Smidts, Carol

    2017-03-01

    This paper studies the task allocation algorithm for a distributed test facility (DTF), which aims to assemble geo-distributed cyber (software) and physical (hardware in the loop components into a prototype cyber-physical system (CPS). This allows low cost testing on an early conceptual prototype (ECP) of the ultimate CPS (UCPS) to be developed. The DTF provides an instrumentation interface for carrying out reliability experiments remotely such as fault propagation analysis and in-situ testing of hardware and software components in a simulated environment. Unfortunately, the geo-distribution introduces an overhead that is not inherent to the UCPS, i.e. a significant time delay in communication that threatens the stability of the ECP and is not an appropriate representation of the behavior of the UCPS. This can be mitigated by implementing a task allocation algorithm to find a suitable configuration and assign the software components to appropriate computational locations, dynamically. This would allow the ECP to operate more efficiently with less probability of being unstable due to the delays introduced by geo-distribution. The task allocation algorithm proposed in this work uses a Monte Carlo approach along with Dynamic Programming to identify the optimal network configuration to keep the time delays to a minimum.

  8. Delay of Vehicle Motion in Traffic Dynamics

    CERN Document Server

    Bando, M; Nakanishi, K; Nakayama, A; Bando, Masako; Hasebe, Katsuya; Nakanishi, Ken; Nakayama, Akihiro

    1996-01-01

    We demonstrate that in Optimal Velocity Model (OVM) delay times of vehicles coming from the dynamical equation of motion of OVM almost explain the order of delay times observed in actual traffic flows without introducing explicit delay times. Delay times in various cases are estimated: the case of a leader vehicle and its follower, a queue of vehicles controlled by traffic lights and many-vehicle case of highway traffic flow. The remarkable result is that in most of the situation for which we can make a reasonable definition of a delay time, the obtained delay time is of order 1 second.

  9. Novice supervisors' tasks and training

    DEFF Research Database (Denmark)

    Nielsen, Jan; Jacobsen, Claus Haugaard; Mathiesen, Birgit Bork

    2012-01-01

    were confronted with complicated jobs, e.g., group, internal and interdisciplinary supervision, but were not prepared, i.e. trained, prior to these tasks. These findings imply that more training is needed for novice supervisors. Preferably, this training should be introduced before, or at least...... parallel to, the first supervisor tasks, preparing the novice supervisors for the often complicated tasks they are meeting....

  10. Principles of Communicative Task Design.

    Science.gov (United States)

    Nunan, David

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

  11. TASK: Let's Have a Party!

    Science.gov (United States)

    Rees, James

    2012-01-01

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

  12. TASK: Let's Have a Party!

    Science.gov (United States)

    Rees, James

    2012-01-01

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

  13. Delay locked loop integrated circuit.

    Energy Technology Data Exchange (ETDEWEB)

    Brocato, Robert Wesley

    2007-10-01

    This report gives a description of the development of a Delay Locked Loop (DLL) integrated circuit (IC). The DLL was developed and tested as a stand-alone IC test chip to be integrated into a larger application specific integrated circuit (ASIC), the Quadrature Digital Waveform Synthesizer (QDWS). The purpose of the DLL is to provide a digitally programmable delay to enable synchronization between an internal system clock and external peripherals with unknown clock skew. The DLL was designed and fabricated in the IBM 8RF process, a 0.13 {micro}m CMOS process. It was designed to operate with a 300MHz clock and has been tested up to 500MHz.

  14. Minimum Delay Moving Object Detection

    KAUST Repository

    Lao, Dong

    2017-01-08

    We present a general framework and method for detection of an object in a video based on apparent motion. The object moves relative to background motion at some unknown time in the video, and the goal is to detect and segment the object as soon it moves in an online manner. Due to unreliability of motion between frames, more than two frames are needed to reliably detect the object. Our method is designed to detect the object(s) with minimum delay, i.e., frames after the object moves, constraining the false alarms. Experiments on a new extensive dataset for moving object detection show that our method achieves less delay for all false alarm constraints than existing state-of-the-art.

  15. Time delay and distance measurement

    Science.gov (United States)

    Abshire, James B. (Inventor); Sun, Xiaoli (Inventor)

    2011-01-01

    A method for measuring time delay and distance may include providing an electromagnetic radiation carrier frequency and modulating one or more of amplitude, phase, frequency, polarization, and pointing angle of the carrier frequency with a return to zero (RZ) pseudo random noise (PN) code. The RZ PN code may have a constant bit period and a pulse duration that is less than the bit period. A receiver may detect the electromagnetic radiation and calculate the scattering profile versus time (or range) by computing a cross correlation function between the recorded received signal and a three-state RZ PN code kernel in the receiver. The method also may be used for pulse delay time (i.e., PPM) communications.

  16. Air congestion delay: a review

    Directory of Open Access Journals (Sweden)

    Daniel Alberto Pamplona

    2016-04-01

    Full Text Available This article is a literature review of the air congestion delay and its costs. Air congestion is a worldwide problem. Its existence brings costs for airlines and discomfort for passengers. With the increasing demand for air transport, the study of air congestion has attracted the attention of many researchers around the world. The cause for the delays is erroneously attributed only to the lack of infrastructure investments. The literature review shows that other factors such as population growth, increasing standards of living, lack of operational planning and environmental issues exercise decisive influence. Several studies have been conducted in order to analyze and propose solutions to this problem that affects society as a whole.

  17. Delayed amputation in lower limb trauma: an analysis of factors leading to delayed amputation.

    Science.gov (United States)

    Thiagarajan, P

    1999-03-01

    An in-depth analysis of the course of events leading to 49 delayed amputation of the lower extremity in 47 patients with open lower limb fractures is presented. Seventeen amputations were performed within one month mainly for vascular reasons. Eleven were between one month and one year, due to persistent sepsis and 21 amputations were performed more than a year after the original injury for infected non-union. Below-knee amputation was done in 32 limbs, above-knee amputation in 13 limbs and Symes' amputation in 4 limbs. The delay in timing of the amputation was analysed with respect to the nature of the injury, the primary treatment and the Mangled Extremity Severity Score (MESS). The MESS score was computed for all injuries and a score of 7 or more predicted an early amputation. We suggest that in all severe lower limb injuries, particularly in Type III C fractures with associated neurological injury, the benefits of an early amputation be considered as an alternative to a limb salvage procedure.

  18. Teriparatide Induced Delayed Persistent Hypercalcemia

    Directory of Open Access Journals (Sweden)

    Nirosshan Thiruchelvam

    2014-01-01

    Full Text Available Teriparatide, a recombinant PTH, is an anabolic treatment for osteoporosis that increases bone density. Transient hypercalcemia is a reported side effect of teriparatide that is seen few hours following administration of teriparatide and resolves usually within 16 hours of drug administration. Persistent hypercalcemia, although not observed in clinical trials, is rarely reported. The current case describes a rare complication of teriparatide induced delayed persistent hypercalcemia.

  19. Six Channel Digital Delay Generator

    Science.gov (United States)

    1980-01-01

    Historically, delays were generated by R-C networks that fired thyratrons to provide the re- quired output pulses. Because of severe electrical interference...instruction manual. The system clock was an M. F. electronics model 5401-1 in a printed circuit mounting package. This particular model has a 10 MHz...constructed in-house to provide the high voltages required to trip flash x-ray systems and thyratron controlled firing units. Details of this circuit are

  20. Assembly delay line pulse generators

    CERN Document Server

    1971-01-01

    Assembly of six of the ten delay line pulse generators that will power the ten kicker magnet modules. One modulator part contains two pulse generators. Capacitors, inductances, and voltage dividers are in the oil tank on the left. Triggered high-pressure spark gap switches are on the platforms on the right. High voltage pulse cables to the kicker magnet emerge under the spark gaps. In the centre background are the assembled master gaps.

  1. Reduced Delay of Gratification and Effortful Control among Young Children with Autism Spectrum Disorders

    Science.gov (United States)

    Faja, Susan; Dawson, Geraldine

    2015-01-01

    We explored internal control of behavior using direct observation and parent report. Previous research has found that both the delay of gratification task and parent-reported effortful control predict later social ability and more positive outcomes in typically developing children. Children with autism spectrum disorder have previously been…

  2. Age and Overt Verbalization in Delay-Maintenance Behavior in Children

    Science.gov (United States)

    Toner, Ignatius J.; Smith, Romayne A.

    1977-01-01

    This study investigated the effect of overt self-verbalization of various contents on the delay maintenance behavior of preschool, second grade and third grade children in a task in which the child's possession of accumulating candy rewards was made contingent upon the child's stopping further accumulation. (BD)

  3. The Negative Effects of Positive Reinforcement in Teaching Children with Developmental Delay.

    Science.gov (United States)

    Biederman, Gerald B.; And Others

    1994-01-01

    This study compared the performance of 12 children (ages 4 to 10) with developmental delay, each trained in 2 tasks, one through interactive modeling (with or without verbal reinforcement) and the other through passive modeling. Results showed that passive modeling produced better rated performance than interactive modeling and that verbal…

  4. Motor Asymmetry and Substantia Nigra Volume Are Related to Spatial Delayed Response Performance in Parkinson Disease

    Science.gov (United States)

    Foster, Erin R.; Black, Kevin J.; Antenor-Dorsey, Jo Ann V.; Perlmutter, Joel S.; Hershey, Tamara

    2008-01-01

    Studies suggest motor deficit asymmetry may help predict the pattern of cognitive impairment in individuals with Parkinson disease (PD). We tested this hypothesis using a highly validated and sensitive spatial memory task, spatial delayed response (SDR), and clinical and neuroimaging measures of PD asymmetry. We predicted SDR performance would be…

  5. Effect of Presentation Modality on Immediate and Delayed Recall in Individuals with Alzheimer's Disease

    Science.gov (United States)

    Mahendra, Nidhi; Bayles, Kathryn A.; Harris, Frances P.

    2005-01-01

    Episodic memory (EM) deficits are the hall-mark of Alzheimer's disease (AD). Story-retelling tasks are particularly sensitive to EM impairments and require participants to recall a short story immediately and after a delay. The purpose of this study was to determine whether presentation modality influences story recall in AD participants. Thirty…

  6. A quantum delayed choice experiment

    CERN Document Server

    Peruzzo, Alberto; Brunner, Nicolas; Popescu, Sandu; O'Brien, Jeremy L

    2012-01-01

    Quantum systems exhibit particle-like or wave-like behaviour depending on the experimental apparatus they are confronted by. This wave-particle duality is at the heart of quantum mechanics, and is fully captured in Wheeler's famous delayed choice gedanken experiment. In this variant of the double slit experiment, the observer chooses to test either the particle or wave nature of a photon after it has passed through the slits. Here we report on a quantum delayed choice experiment, based on a quantum controlled beam-splitter, in which both particle and wave behaviours can be investigated simultaneously. The genuinely quantum nature of the photon's behaviour is tested via a Bell inequality, which here replaces the delayed choice of the observer. We observe strong Bell inequality violations, thus showing that no model in which the photon knows in advance what type of experiment it will be confronted by, hence behaving either as a particle or as wave, can account for the experimental data.

  7. Minimum Delay Moving Object Detection

    KAUST Repository

    Lao, Dong

    2017-05-14

    This thesis presents a general framework and method for detection of an object in a video based on apparent motion. The object moves, at some unknown time, differently than the “background” motion, which can be induced from camera motion. The goal of proposed method is to detect and segment the object as soon it moves in an online manner. Since motion estimation can be unreliable between frames, more than two frames are needed to reliably detect the object. Observing more frames before declaring a detection may lead to a more accurate detection and segmentation, since more motion may be observed leading to a stronger motion cue. However, this leads to greater delay. The proposed method is designed to detect the object(s) with minimum delay, i.e., frames after the object moves, constraining the false alarms, defined as declarations of detection before the object moves or incorrect or inaccurate segmentation at the detection time. Experiments on a new extensive dataset for moving object detection show that our method achieves less delay for all false alarm constraints than existing state-of-the-art.

  8. Infant overweight is associated with delayed motor development

    Science.gov (United States)

    Slining, Meghan; Adair, Linda S.; Goldman, Barbara Davis; Borja, Judith B.; Bentley, Margaret

    2012-01-01

    Objective To examine how infant overweight and high subcutaneous fat relate to infant motor development. Study design Participants are from the Infant Care, Feeding, and Risk of Obesity Project, a prospective, longitudinal study of low-income African American mother-infant dyads assessed from 3 -18 months of age (836 observations on 217 infants). Exposures were overweight (weight-for-length z-score ≥90th percentile of 2000 CDC/NCHS growth reference) and high subcutaneous fat (sum of three skinfold measurements >90th percentile of our sample). Motor development was assessed using Bayley Scales of Infant Development-II. Developmental delay was characterized as a standardized Psychomotor Development Index score <85. Longitudinal models estimated developmental outcomes as functions of time-varying overweight and subcutaneous fat, controlling for age and sex. Alternate models tested concurrent and lagged relationships (prior weight or subcutaneous fat predicting current motor development). Results Motor delay was 1.80 times as likely in overweight compared with non-overweight infants (95% CI:1.09, 2.97), and 2.32 times as likely in infants with high subcutaneous fat compared with lower subcutaneous fat (95% CI:1.26, 4.29). High subcutaneous fat was also associated with delay in subsequent motor development (OR=2.27, 95% CI:1.08, 4.76). Conclusions Pediatric overweight and high subcutaneous fat are associated with delayed infant motor development. PMID:20227724

  9. Pattern reverberation in networks of excitable systems with connection delays

    Science.gov (United States)

    Lücken, Leonhard; Rosin, David P.; Worlitzer, Vasco M.; Yanchuk, Serhiy

    2017-01-01

    We consider the recurrent pulse-coupled networks of excitable elements with delayed connections, which are inspired by the biological neural networks. If the delays are tuned appropriately, the network can either stay in the steady resting state, or alternatively, exhibit a desired spiking pattern. It is shown that such a network can be used as a pattern-recognition system. More specifically, the application of the correct pattern as an external input to the network leads to a self-sustained reverberation of the encoded pattern. In terms of the coupling structure, the tolerance and the refractory time of the individual systems, we determine the conditions for the uniqueness of the sustained activity, i.e., for the functionality of the network as an unambiguous pattern detector. We point out the relation of the considered systems with cyclic polychronous groups and show how the assumed delay configurations may arise in a self-organized manner when a spike-time dependent plasticity of the connection delays is assumed. As excitable elements, we employ the simplistic coincidence detector models as well as the Hodgkin-Huxley neuron models. Moreover, the system is implemented experimentally on a Field-Programmable Gate Array.

  10. Dynamics of an HBV/HCV infection model with intracellular delay and cell proliferation

    Science.gov (United States)

    Zhang, Fengqin; Li, Jianquan; Zheng, Chongwu; Wang, Lin

    2017-01-01

    A new mathematical model of hepatitis B/C virus (HBV/HCV) infection which incorporates the proliferation of healthy hepatocyte cells and the latent period of infected hepatocyte cells is proposed and studied. The dynamics is analyzed via Pontryagin's method and a newly proposed alternative geometric stability switch criterion. Sharp conditions ensuring stability of the infection persistent equilibrium are derived by applying Pontryagin's method. Using the intracellular delay as the bifurcation parameter and applying an alternative geometric stability switch criterion, we show that the HBV/HCV infection model undergoes stability switches. Furthermore, numerical simulations illustrate that the intracellular delay can induce complex dynamics such as persistence bubbles and chaos.

  11. First interim report of the Federal Fleet Conversion Task Force

    Energy Technology Data Exchange (ETDEWEB)

    1993-08-01

    The Federal Fleet Conversion Task Force was created by Executive Order 12844, signed by President Clinton on April 21, 1993. In the Order, the President directed that purchases of alternative fueled vehicles by the Federal Government be substantially increased beyond the levels required by current law. The President charged the Task Force with developing recommendations for carrying out the Executive Order, with special emphasis on setting a course that will lead to the widespread use of alternative fueled vehicles by Federal, State, and local government fleets, by private fleets and, ultimately, by individuals. The chief recommendation of the Task Force is the establishment of a Presidential Clean Cities Initiative. To support creation of the Presidential Initiative, the Task Force identified 38 cities and regions, prioritized into three tiers, for concentrating the Initiative`s efforts in Fiscal Years 1994 through 1996. This concentration of effort is key to the effectiveness of the Initiative. The 38 cities and regions would receive priority funding for Federal vehicle purchases and for infrastructure development. In addition, the Task Force has made specific recommendations for overcoming numerous regulatory, economic, and technical barriers that have slowed the introduction of alternative fueled vehicles into general use.

  12. Alternative vaccination schedule preferences among parents of young children.

    Science.gov (United States)

    Dempsey, Amanda F; Schaffer, Sarah; Singer, Dianne; Butchart, Amy; Davis, Matthew; Freed, Gary L

    2011-11-01

    Increasing numbers of parents use alternative vaccination schedules that differ from the recommended childhood vaccination schedule for their children. We sought to describe national patterns of alternative vaccination schedule use and the potential "malleability" of parents' current vaccination schedule choices. We performed a cross-sectional, Internet-based survey of a nationally representative sample of parents of children 6 months to 6 years of age. Bivariate and multivariate analyses determined associations between demographic and attitudinal factors and alternative vaccination schedule use. The response rate was 61% (N = 748). Of the 13% of parents who reported following an alternative vaccination schedule, most refused only certain vaccines (53%) and/or delayed some vaccines until the child was older (55%). Only 17% reported refusing all vaccines. In multivariate models, nonblack race and not having a regular health care provider for the child were the only factors significantly associated with higher odds of using an alternative schedule. A large proportion of alternative vaccinators (30%) reported having initially followed the recommended vaccination schedule. Among parents following the recommended vaccination schedule, 28% thought that delaying vaccine doses was safer than the schedule they used, and 22% disagreed that the best vaccination schedule to follow was the one recommended by vaccination experts. More than 1 of 10 parents of young children currently use an alternative vaccination schedule. In addition, a large proportion of parents currently following the recommended schedule seem to be "at risk" for switching to an alternative schedule.

  13. Nonstrategic Contributions to Putatively Strategic Effects in Selective Attention Tasks

    Science.gov (United States)

    Risko, Evan F.; Blais, Chris; Stolz, Jennifer A.; Besner, Derek

    2008-01-01

    Proportion compatible manipulations are often used to index strategic processes in selective attention tasks. Here, a subtle confound in proportion compatible manipulations is considered. Specifically, as the proportion of compatible trials increases, the ratio of complete repetitions and complete alternations to partial repetitions increases on…

  14. Optical Vorticity Meter Task

    Science.gov (United States)

    1978-05-05

    should have a high-reflect- ______ ing power R of 95% to SO% transmitting only a small * percentage of the light. An auxiliary, usually much Ftc.1. wo- eam ...medium occupies the entire optical path of the ring cavity, which is drilled out of a Magneto-optic alternatives monolithic block of a special low...as the light So urce the rilninim delectable rotation rate i.s (for 1? 15 cm, c, = 2 dBr /hu, R - 10 se~,and to 0.5): -1.5 X 10 -9 rad,ec

  15. Alternative Solar Indices

    Energy Technology Data Exchange (ETDEWEB)

    Lantz, L.J.

    1980-07-01

    Possible alternative Solar Indices which could either be a perturbation from the currently defined Solar Index or possible indices based on current technologies for other media markets are discussed. An overview is given of the current project, including the logic that was utilized in defining its current structure and then alternative indices and definitions are presented and finally, recommendations are made for adopting alternative indices.

  16. On alternating quantum walks

    Science.gov (United States)

    Rousseva, Jenia; Kovchegov, Yevgeniy

    2017-03-01

    We study an inhomogeneous quantum walk on a line that evolves according to alternating coins, each a rotation matrix. For the quantum walk with the coin alternating between clockwise and counterclockwise rotations by the same angle, we derive a closed form solution for the propagation of probabilities, and provide its asymptotic approximation via the method of stationary phase. Finally, we observe that for a x03c0;/4 angle, this alternating rotation walk will replicate the renown Hadamard walk.

  17. On an Alternative Cosmology

    CERN Document Server

    Vankov, A

    1998-01-01

    The suggested alternative cosmology is based on the idea of barion symmetric universe, in which our home universe is a representative of multitude of typical matter and antimatter universes. This alternative concept gives a physically reasonable explanation of all major problems of the Standard Cosmological Model. Classification Code MSC: Cosmology 524.8 Key words: standard cosmological model, alternative cosmology, barionic symmetry, typical universe, quasars, cosmic rays.

  18. An Investigation of Differential Reinforcement of Alternative Behavior without Extinction

    Science.gov (United States)

    Athens, Elizabeth S.; Vollmer, Timothy R.

    2010-01-01

    We manipulated relative reinforcement for problem behavior and appropriate behavior using differential reinforcement of alternative behavior (DRA) without an extinction component. Seven children with developmental disabilities participated. We manipulated duration (Experiment 1), quality (Experiment 2), delay (Experiment 3), or a combination of…

  19. AN INVESTIGATION OF DIFFERENTIAL REINFORCEMENT OF ALTERNATIVE BEHAVIOR WITHOUT EXTINCTION

    OpenAIRE

    Athens, Elizabeth S; Vollmer, Timothy R

    2010-01-01

    We manipulated relative reinforcement for problem behavior and appropriate behavior using differential reinforcement of alternative behavior (DRA) without an extinction component. Seven children with developmental disabilities participated. We manipulated duration (Experiment 1), quality (Experiment 2), delay (Experiment 3), or a combination of each (Experiment 4), such that reinforcement favored appropriate behavior rather than problem behavior even though problem behavior still produced rei...

  20. Application of ray-traced tropospheric slant delays to geodetic VLBI analysis

    Science.gov (United States)

    Hofmeister, Armin; Böhm, Johannes

    2017-02-01

    The correction of tropospheric influences via so-called path delays is critical for the analysis of observations from space geodetic techniques like the very long baseline interferometry (VLBI). In standard VLBI analysis, the a priori slant path delays are determined using the concept of zenith delays, mapping functions and gradients. The a priori use of ray-traced delays, i.e., tropospheric slant path delays determined with the technique of ray-tracing through the meteorological data of numerical weather models (NWM), serves as an alternative way of correcting the influences of the troposphere on the VLBI observations within the analysis. In the presented research, the application of ray-traced delays to the VLBI analysis of sessions in a time span of 16.5 years is investigated. Ray-traced delays have been determined with program RADIATE (see Hofmeister in Ph.D. thesis, Department of Geodesy and Geophysics, Faculty of Mathematics and Geoinformation, Technische Universität Wien. http://resolver.obvsg.at/urn:nbn:at:at-ubtuw:1-3444, 2016) utilizing meteorological data provided by NWM of the European Centre for Medium-Range Weather Forecasts (ECMWF). In comparison with a standard VLBI analysis, which includes the tropospheric gradient estimation, the application of the ray-traced delays to an analysis, which uses the same parameterization except for the a priori slant path delay handling and the used wet mapping factors for the zenith wet delay (ZWD) estimation, improves the baseline length repeatability (BLR) at 55.9% of the baselines at sub-mm level. If no tropospheric gradients are estimated within the compared analyses, 90.6% of all baselines benefit from the application of the ray-traced delays, which leads to an average improvement of the BLR of 1 mm. The effects of the ray-traced delays on the terrestrial reference frame are also investigated. A separate assessment of the RADIATE ray-traced delays is carried out by comparison to the ray-traced delays from the

  1. Application of ray-traced tropospheric slant delays to geodetic VLBI analysis

    Science.gov (United States)

    Hofmeister, Armin; Böhm, Johannes

    2017-08-01

    The correction of tropospheric influences via so-called path delays is critical for the analysis of observations from space geodetic techniques like the very long baseline interferometry (VLBI). In standard VLBI analysis, the a priori slant path delays are determined using the concept of zenith delays, mapping functions and gradients. The a priori use of ray-traced delays, i.e., tropospheric slant path delays determined with the technique of ray-tracing through the meteorological data of numerical weather models (NWM), serves as an alternative way of correcting the influences of the troposphere on the VLBI observations within the analysis. In the presented research, the application of ray-traced delays to the VLBI analysis of sessions in a time span of 16.5 years is investigated. Ray-traced delays have been determined with program RADIATE (see Hofmeister in Ph.D. thesis, Department of Geodesy and Geophysics, Faculty of Mathematics and Geoinformation, Technische Universität Wien. http://resolver.obvsg.at/urn:nbn:at:at-ubtuw:1-3444, 2016) utilizing meteorological data provided by NWM of the European Centre for Medium-Range Weather Forecasts (ECMWF). In comparison with a standard VLBI analysis, which includes the tropospheric gradient estimation, the application of the ray-traced delays to an analysis, which uses the same parameterization except for the a priori slant path delay handling and the used wet mapping factors for the zenith wet delay (ZWD) estimation, improves the baseline length repeatability (BLR) at 55.9% of the baselines at sub-mm level. If no tropospheric gradients are estimated within the compared analyses, 90.6% of all baselines benefit from the application of the ray-traced delays, which leads to an average improvement of the BLR of 1 mm. The effects of the ray-traced delays on the terrestrial reference frame are also investigated. A separate assessment of the RADIATE ray-traced delays is carried out by comparison to the ray-traced delays from the

  2. On Hamlet's Delay in the Revenge

    Institute of Scientific and Technical Information of China (English)

    刘莎

    2009-01-01

    Hamlet is a representative tragedy written by Shakespeare. Question on Hemlet's delay has been drawing the interest of many literature critics. It is still under discussion today. This thesis focuses on analyzing the reasons for Hamlet's delay in the revenge.

  3. Timing matters: the impact of immediate and delayed feedback on artificial language learning.

    Science.gov (United States)

    Opitz, Bertram; Ferdinand, Nicola K; Mecklinger, Axel

    2011-01-01

    In the present experiment, we used event-related potentials (ERP) to investigate the role of immediate and delayed feedback in an artificial grammar learning (AGL) task. Two groups of participants were engaged in classifying non-word strings according to an underlying rule system, not known to the participants. Visual feedback was provided after each classification either immediately or with a short delay of 1 s. Both groups were able to learn the artificial grammar system as indicated by an increase in classification performance. However, the gain in performance was significantly larger for the group receiving immediate feedback as compared to the group receiving delayed feedback. Learning was accompanied by an increase in P300 activity in the ERP for delayed as compared to immediate feedback. Irrespective of feedback delay, both groups exhibited learning related decreases in the feedback-related positivity (FRP) elicited by positive feedback only. The feedback-related negativity (FRN), however, remained constant over the course of learning. These results suggest, first, that delayed feedback is less effective for AGL as task requirements are very demanding, and second, that the FRP elicited by positive prediction errors decreases with learning while the FRN to negative prediction errors is elicited in an all-or-none fashion by negative feedback throughout the entire experiment.

  4. Undervaluing delayed rewards explains adolescents’ impulsivity in inter-temporal choice: an ERP study

    Science.gov (United States)

    Huang, Yunyun; Hu, Ping; Li, Xueting

    2017-01-01

    Adolescence has frequently been characterized as a period of choice impulsivity relative to adulthood. According to the control-integrated valuation model of inter-temporal choice, this choice impulsivity may be driven partly by an age-related difference in reward processing. We hypothesized that, compared to adults, adolescents would undervalue delayed rewards during reward processing and would thus be more impulsive in inter-temporal choice. To test this hypothesis at the behavioural and neural levels, we first measured the choice impulsivity of 18 adolescents and 19 adults using a delay discounting task (DDT). Then, we recorded event-related potentials (ERPs) from the participants while they were performing the valuation task, in which monetary gains and losses were either immediate or delayed. The behavioural results showed that adolescents were more impulsive than adults in the DDT. The ERP results showed that, whilst both groups valued immediate rewards, implied by a similarly strong feedback-related negativity (FRN) effect associated with immediate outcomes, adolescents devalued delayed rewards more than adults did, as they produced a significantly smaller FRN effect associated with delayed outcomes. As predicted, the mediation analysis revealed that the adolescents’ lower FRN effect of delayed outcomes underpinned their stronger impulsive decision making in the DDT. PMID:28198452

  5. Timing matters: The impact of immediate and delayed feedback on artificial language learning

    Directory of Open Access Journals (Sweden)

    Bertram Opitz

    2011-02-01

    Full Text Available In the present experiment, we used event-related potentials (ERP to investigate the role of immediate and delayed feedback in an artificial grammar learning task. Two groups of participants were engaged in classifying non-word strings according to an underlying rule system, not known to the participants. Visual feedback was provided after each classification either immediately or with a short delay of one second. Both groups were able to learn the artificial grammar system as indicated by an increase in classification performance. However, the gain in performance was significantly larger for the group receiving immediate feedback as compared to the group receiving delayed feedback. Learning was accompanied by an increase in P300 activity in the ERP for delayed as compared to immediate feedback. Irrespective of feedback delay, both groups exhibited learning related decreases in the feedback-related positivity (FRP elicited by positive feedback only. The feedback-related negativity (FRN, however, remained constant over the course of learning. These results suggest, first, that delayed feedback is less effective for artificial grammar learning as task requirements are very demanding, and second, that the FRP elicited by positive prediction errors decreases with learning while the FRN to negative prediction errors is elicited in an all-or-none fashion by negative feedback throughout the entire experiment.

  6. Undervaluing delayed rewards explains adolescents' impulsivity in inter-temporal choice: an ERP study.

    Science.gov (United States)

    Huang, Yunyun; Hu, Ping; Li, Xueting

    2017-02-15

    Adolescence has frequently been characterized as a period of choice impulsivity relative to adulthood. According to the control-integrated valuation model of inter-temporal choice, this choice impulsivity may be driven partly by an age-related difference in reward processing. We hypothesized that, compared to adults, adolescents would undervalue delayed rewards during reward processing and would thus be more impulsive in inter-temporal choice. To test this hypothesis at the behavioural and neural levels, we first measured the choice impulsivity of 18 adolescents and 19 adults using a delay discounting task (DDT). Then, we recorded event-related potentials (ERPs) from the participants while they were performing the valuation task, in which monetary gains and losses were either immediate or delayed. The behavioural results showed that adolescents were more impulsive than adults in the DDT. The ERP results showed that, whilst both groups valued immediate rewards, implied by a similarly strong feedback-related negativity (FRN) effect associated with immediate outcomes, adolescents devalued delayed rewards more than adults did, as they produced a significantly smaller FRN effect associated with delayed outcomes. As predicted, the mediation analysis revealed that the adolescents' lower FRN effect of delayed outcomes underpinned their stronger impulsive decision making in the DDT.

  7. Alternative medicine studies

    National Research Council Canada - National Science Library

    2011-01-01

    A peer-reviewed, open-access journal about alternative medicine systems including acupuncture, anthroposophic medicine, ayurveda, chiropractic, herbalism and natural products, homeopathy, naturopathy...

  8. Alternative Auditing Approaches

    Energy Technology Data Exchange (ETDEWEB)

    Kandt, Alicen J [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-09-15

    This presentation for the 2017 Energy Exchange in Tampa, Florida, offers information about advanced auditing technologies and techniques including alternative auditing approaches and considerations and caveats.

  9. Brandmodstandsbidrag for alternative isoleringsmaterialer

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan de Place

    2001-01-01

    Resume af rapport om alternative isoleringsmaterialers brandmodstandsbidrag, udarbejdet af Dansk Brandteknisk Institut under Energistyrelsens udviklingsprogram "Miljø- og arbejdsmiljøvenlig isolering"...

  10. Delay of gratification and time comprehension is impaired in very preterm children at the age of 4years.

    Science.gov (United States)

    Hüning, B M; Assing, B; Weishaupt, E; Dransfeld, F; Felderhoff-Müser, U; Zmyj, N

    2017-09-24

    Very preterm infants more likely exhibit deficient executive functions than term born controls. Delay of gratification, as part of the executive functions, allows for rejecting an immediate in favor of a greater future reward. Time comprehension might help to delay gratification. We hypothesized that delay of gratification and time comprehension is less developed in preterm children and that time comprehension is associated with the ability to wait for a greater reward. Very preterm children (preterm subjects (12 female; median: gestational age (GA) 28.3weeks, corrected age 4years, 22days) and 26 controls (16 female, median GA: 40.0weeks, age 4years, 25days) participated. Correct answers in the time comprehension and receptive language task, waiting time in the delay-of-gratification task were measured. Preterm subjects had less time comprehension than controls (43% vs. 53%, p=0.017, one-tailed) but receptive language skills were similar. Waiting time in the delay-of-gratification task was 3:42min in preterm subjects, versus 10:09min in controls (p=0.043, one-tailed). Even after controlling for language skills, waiting time correlated positively with time comprehension in both groups (r=0.399, p=0.004, two-tailed). Preterm children's time comprehension and delay of gratification ability is impaired. Future research is warranted to investigate whether training in time comprehension increases the ability to delay gratification. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Influence of Ongoing Task Difficulty and Motivation Level on Children's Prospective Memory in a Chinese Sample.

    Science.gov (United States)

    Han, Pi-Guo; Han, Lei; Bian, Yu-Long; Tian, Yu; Xu, Min-Xia; Gao, Feng-Qiang

    2017-01-01

    Prospective memory (PM) is the process associated with the task of realizing delayed intentions in the future. Researchers distinguish two types of PM, namely time-based PM (tbPM) and event-based PM (ebPM). Experiment 1 investigated the developmental trajectory of 3- to 5-year-old preschool children's PM ability, and the occurrence of delayed retrieval (children execute the PM task in a larger window of opportunity) in both tbPM and ebPM tasks. Results revealed that the 5-year-old children outperformed the 3- and 4-year-old children in PM. Moreover, delayed retrieval was more likely to occur in tbPM task than in ebPM task. In Experiment 2, the influence of ongoing task (OT) difficulty on PM performance was investigated with a sample of 5-year-old children. Results revealed no significant effect of OT difficulty on PM performance. In Experiment 3, we improved children's motivation level to complete the OT, then explored the influence of OT difficulty on children's PM performance. Results revealed that the effect of OT difficulty on PM performance became significant after increasing the children's motivation to complete the OT. These results provide insights into the mechanism of attentional resource allocation in PM tasks and have crucial educational and social implications.

  12. Units of analysis in task-analytic research.

    Science.gov (United States)

    Haring, T G; Kennedy, C H

    1988-01-01

    We develop and discuss four criteria for evaluating the appropriateness of units of analysis for task-analytic research and suggest potential alternatives to the units of analysis currently used. Of the six solutions discussed, the most commonly used unit of analysis in current behavior analytic work, percentage correct, meets only one of the four criteria. Five alternative units of analysis are presented and evaluated: (a) percentage of opportunities to perform meeting criterion, (b) trials to criteria, (c) cumulative competent performances, (d) percentage correct with competent performance coded, and (e) percentage correct with competent performance coded and a grid showing performance on individual steps of the task analysis. Of the solutions evaluated, only one--percentage correct with competent performance coded and a task analysis grid--met all four criteria.

  13. Music-dependent memory in immediate and delayed word recall.

    Science.gov (United States)

    Balch, W R; Bowman, K; Mohler, L

    1992-01-01

    Undergraduate volunteers rated a series of words for pleasantness while hearing a particular background music. The subjects in Experiment 1 received, immediately or after a 48-h delay, an unexpected word-recall test in one of the following musical cue contexts: same cue (S), different cue (D), or no cue (N). For immediate recall, context dependency (S-D) was significant but same-cue facilitation (S-N) was not. No cue effects at all were found for delayed recall, and there was a significant interaction between cue and retention interval. A similar interaction was also found in Experiment 3, which was designed to rule out an alternative explanation with respect to distraction. When the different musical selection was changed specifically in either tempo or form (genre), only pieces having an altered tempo produced significantly lower immediate recall compared with the same pieces (Experiment 2). The results support a stimulus generalization view of music-dependent memory.

  14. Nonverbal imitation skills in children with specific language delay.

    Science.gov (United States)

    Dohmen, Andrea; Chiat, Shula; Roy, Penny

    2013-10-01

    Research in children with language problems has focussed on verbal deficits, and we have less understanding of children's deficits with nonverbal sociocognitive skills which have been proposed to be important for language acquisition. This study was designed to investigate elicited nonverbal imitation in children with specific language delay (SLD). It is argued that difficulties in nonverbal imitation, which do not involve the processing of structural aspects of language, may be indicative of sociocognitive deficits. Participants were German-speaking typically developing children (n=60) and children with SLD (n=45) aged 2-3 ½ years. A novel battery of tasks measured their ability to imitate a range of nonverbal target acts that to a greater or lesser extent involve sociocognitive skills (body movements, instrumental acts on objects, pretend acts). Significant group differences were found for all body movement and pretend act tasks, but not for the instrumental act tasks. The poorer imitative performance of the SLD sample was not explained by motor or nonverbal cognitive skills. Thus, it appeared that the nature of the task affected children's imitation performance. It is argued that the ability to establish a sense of connectedness with the demonstrator was at the core of children's imitation difficulty in the SLD sample. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Dynamic Cournot Duopoly Game with Delay

    Directory of Open Access Journals (Sweden)

    A. A. Elsadany

    2014-01-01

    Full Text Available The delay Cournot duopoly game is studied. Dynamical behaviors of the game are studied. Equilibrium points and their stability are studied. The results show that the delayed system has the same Nash equilibrium point and the delay can increase the local stability region.

  16. Modelling delay propagation within an airport network

    NARCIS (Netherlands)

    Pyrgiotis, N.; Malone, K.M.; Odoni, A.

    2013-01-01

    We describe an analytical queuing and network decomposition model developed to study the complex phenomenon of the propagation of delays within a large network of major airports. The Approximate Network Delays (AND) model computes the delays due to local congestion at individual airports and capture

  17. Delayed umbilical cord separation in alloimmune neutropenia.

    OpenAIRE

    Kemp, A S; Lubitz, L

    1993-01-01

    Delayed umbilical cord separation in association with neonatal alloimmune neutropenia is reported. Delayed umbilical cord separation has been described in association with defects in neutrophil function. The present case indicates that deficiency in neutrophil number should also be considered as a cause of delayed cord separation.

  18. Modelling delay propagation within an airport network

    NARCIS (Netherlands)

    Pyrgiotis, N.; Malone, K.M.; Odoni, A.

    2013-01-01

    We describe an analytical queuing and network decomposition model developed to study the complex phenomenon of the propagation of delays within a large network of major airports. The Approximate Network Delays (AND) model computes the delays due to local congestion at individual airports and

  19. Energy Constrained Hierarchical Task Scheduling Algorithm for Mobile Grids

    Directory of Open Access Journals (Sweden)

    Arjun Singh

    2014-05-01

    Full Text Available In mobile grids, scheduling the computation tasks and the communication transactions onto the target architecture is the important problem when a mobile grid environment and a pre-selected architecture are given. Even though the scheduling problem is a traditional topic, almost all previous work focuses on maximizing the performance through the scheduling process. The algorithms developed this way are not suitable for real-time embedded applications, in which the main objective is to minimize the energy consumption of the system under tight performance constraints. This paper entails an energy constrained hierarchical task scheduling algorithm for Mobile Grids to minimize the power consumption of the mobile nodes. The task is rescheduled when the mobile node moves beyond the transmission range. The performance is estimated based on the average delay and packet delivery ratio based on nodes and flows. The performance metrics are analysed using NS-2 simulator.

  20. Effects of a thermal-insulating mouse pad on temperature of forearm and hand during computer tasks

    NARCIS (Netherlands)

    E.M. Meijer; M.A.G. Formanoy; B. Visser; J.K. Sluiter; M.H.W. Frings-Dresen

    2006-01-01

    This laboratory experiment studied the effects of a thermal-insulating mouse pad on arm temperature and comfort during computer work. Fourteen subjects performed two 20-min computer tasks ( a mouse task and a combined task alternating keyboard and mouse use), under three conditions, namely with: 1)

  1. Alternative fiber optic conductor for laboratory practices

    Science.gov (United States)

    Calderon Ocampo, Juan F.; Jaramillo Florez, Samuel A.; Amaya Rodriguez, Juan C.

    1995-10-01

    Due to the high cost and difficulty in obtaining an optical fiber sample to be used in laboratory tests, we have given ourselves the task of looking for an adequate optical-fiber alternative for laboratory practices. We have as a result, found an object that can be used as an alternate optical conductor. This object called 'Venoclisis Hose', is a cylindrical plastic tube, hollow inside, whose main use has been in medical applications as a conveyor of liquids going in or coming out of the human body. In this document, the tests carried out and the results obtained to characterize the venoclisis as an optical fiber are described. This project was undertaken in order to propose the use of Venoclisis as an alternate optical fiber for laboratory work, due primarily to its low costs, as well as how easy it to acquire and measure its parameters as an optical fiber.

  2. BOLD delay times using group delay in sickle cell disease

    Science.gov (United States)

    Coloigner, Julie; Vu, Chau; Bush, Adam; Borzage, Matt; Rajagopalan, Vidya; Lepore, Natasha; Wood, John

    2016-03-01

    Sickle cell disease (SCD) is an inherited blood disorder that effects red blood cells, which can lead to vasoocclusion, ischemia and infarct. This disease often results in neurological damage and strokes, leading to morbidity and mortality. Functional Magnetic Resonance Imaging (fMRI) is a non-invasive technique for measuring and mapping the brain activity. Blood Oxygenation Level-Dependent (BOLD) signals contain also information about the neurovascular coupling, vascular reactivity, oxygenation and blood propagation. Temporal relationship between BOLD fluctuations in different parts of the brain provides also a mean to investigate the blood delay information. We used the induced desaturation as a label to profile transit times through different brain areas, reflecting oxygen utilization of tissue. In this study, we aimed to compare blood flow propagation delay times between these patients and healthy subjects in areas vascularized by anterior, middle and posterior cerebral arteries. In a group comparison analysis with control subjects, BOLD changes in these areas were found to be almost simultaneous and shorter in the SCD patients, because of their increased brain blood flow. Secondly, the analysis of a patient with a stenosis on the anterior cerebral artery indicated that signal of the area vascularized by this artery lagged the MCA signal. These findings suggest that sickle cell disease causes blood propagation modifications, and that these changes could be used as a biomarker of vascular damage.

  3. An alternative parameterization of R-matrix theory

    Energy Technology Data Exchange (ETDEWEB)

    Brune, C.R

    2003-05-05

    An alternative parameterization of R-matrix theory is described which is mathematically equivalent to the standard approach, but which has no level shifts. The positions and partial widths of an arbitrary number of levels can thus be easily fixed in an analysis. These alternative parameters can be converted to standard R-matrix parameters by a straightforward matrix diagonalization procedure, and a 'level matrix' formulation is possible which allows the collision matrix to be expressed directly in terms of the alternative parameters. The applications to radiative capture reactions and {beta}-delayed particle spectra are briefly discussed.

  4. Alternative health insurance schemes

    DEFF Research Database (Denmark)

    Keiding, Hans; Hansen, Bodil O.

    2002-01-01

    In this paper, we present a simple model of health insurance with asymmetric information, where we compare two alternative ways of organizing the insurance market. Either as a competitive insurance market, where some risks remain uninsured, or as a compulsory scheme, where however, the level...... competitive insurance; this situation turns out to be at least as good as either of the alternatives...

  5. Acquisition of Voicing Alternations

    NARCIS (Netherlands)

    Kerkhoff, Annemarie

    2004-01-01

    "Morpho-phonological alternations are central to phonological theory, but little is known about how they are acquired. Acquiring alternations amounts to dealing with variation in a morpheme’s shape depending on its morphological context. It is generally assumed that children start with an initial st

  6. Alternative Schools, Mainstream Education

    Science.gov (United States)

    McKee, Jan; Conner, Evguenia

    2007-01-01

    Alternative education has its own history. Having emerged in the sixties as a response to the social crisis, its goal was primarily to fight increasing bureaucracy and the depersonalization of public education by giving students more freedom and minimal adult supervision. In the eighties, the understanding of "alternative education" narrowed to…

  7. Alternative Fuels Data Center

    Energy Technology Data Exchange (ETDEWEB)

    None

    2013-06-01

    Fact sheet describes the Alternative Fuels Data Center, which provides information, data, and tools to help fleets and other transportation decision makers find ways to reduce petroleum consumption through the use of alternative and renewable fuels, advanced vehicles, and other fuel-saving measures.

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

    Science.gov (United States)

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

    2016-01-01

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

  9. Delayed saccadic eye movements in glaucoma

    Directory of Open Access Journals (Sweden)

    Kanjee R

    2012-11-01

    Full Text Available Raageen Kanjee,1 Yeni H Yücel,1,2 Martin J Steinbach,3,4 Esther G González,3,4 Neeru Gupta1,2,51Ophthalmology and Vision Sciences, Laboratory Medicine and Pathobiology, St Michael's Hospital, University of Toronto, 2Keenan Research Centre at the Li Ka Shing Knowledge Institute of St Michael's Hospital, 3Toronto Western Hospital, University Health Network, 4Centre for Vision Research, York University, 5Glaucoma and Nerve Protection Unit, St Michael's Hospital, Toronto, ON, CanadaPurpose: To determine whether saccadic eye movements are altered in glaucoma patients.Patients and methods: Sixteen patients with glaucoma and 21 control subjects were prospectively studied. Patients participated in a pro-saccade step task. Saccades were recorded using a noninvasive infrared oculometric device with head-mounted target projection. Medians of saccade reaction time, duration, amplitude, and peak velocity; frequency of express saccades; and percentage of trials with direction error were recorded. t-tests were used to compare the glaucoma and age-matched control groups. A correlation analysis of saccade parameters with visual field loss was also performed.Results: Median saccade reaction times were significantly prolonged in glaucoma patients compared with controls (220.9 ± 49.02 ms vs 192.1 ± 31.24 ms; t-test: P = 0.036. Median duration, median amplitude, and median peak velocity of saccades did not show significant differences between glaucoma and control groups (P > 0.05. Frequency of express saccades was significantly decreased in glaucoma patients compared with controls (1.75 ± 2.32 vs 7.0 ± 6.99; t-test: P = 0.007. Saccade parameters in glaucoma patients showed no significant correlation with visual field loss.Conclusion: Saccadic eye movements are significantly delayed in patients with early, moderate, or advanced glaucoma. Determination of median saccade reaction time may offer a novel functional test to quantify visual function in glaucoma

  10. Reactor shutdown delays medical procedures

    Science.gov (United States)

    Gwynne, Peter

    2008-01-01

    A longer-than-expected maintenance shutdown of the Canadian nuclear reactor that produces North America's entire supply of molybdenum-99 - from which the radioactive isotopes technetium-99 and iodine-131 are made - caused delays to the diagnosis and treatment of thousands of seriously ill patients last month. Technetium-99 is a key component of nuclear-medicine scans, while iodine-131 is used to treat cancer and other diseases of the thyroid. Production eventually resumed, but only after the Canadian government had overruled the Canadian Nuclear Safety Commission (CNSC), which was still concerned about the reactor's safety.

  11. Delay modeling in logic simulation

    Energy Technology Data Exchange (ETDEWEB)

    Acken, J. M.; Goldstein, L. H.

    1980-01-01

    As digital integrated circuit size and complexity increases, the need for accurate and efficient computer simulation increases. Logic simulators such as SALOGS (SAndia LOGic Simulator), which utilize transition states in addition to the normal stable states, provide more accurate analysis than is possible with traditional logic simulators. Furthermore, the computational complexity of this analysis is far lower than that of circuit simulation such as SPICE. An eight-value logic simulation environment allows the use of accurate delay models that incorporate both element response and transition times. Thus, timing simulation with an accuracy approaching that of circuit simulation can be accomplished with an efficiency comparable to that of logic simulation. 4 figures.

  12. The delay effect on outcome evaluation: results from an Event-related Potential study

    Directory of Open Access Journals (Sweden)

    Chen eQu

    2013-11-01

    Full Text Available Behavioral studies demonstrate that the timing of receiving gains or losses affects decision-making, a phenomenon known as temporal discounting, as participants are inclined to prefer immediate rewards over delayed ones and vice versa for losses. The present study used the event-related potential (ERP technique with a simple gambling task to investigate how delayed rewards and losses affected the brain activity in outcome evaluations made by 20 young adults. Statistical analysis revealed a larger feedback related negativity (FRN effect between loss and gain following immediate outcomes than following future outcomes. In addition, delay impacted FRN only in gain conditions, with delayed winning eliciting a more negative FRN than immediatewinning. These results suggest that temporal discounting and sign effect could be encoded in the FRN in the early stage of outcome evaluation.

  13. Delay Variation Model with Two Service Queues

    Directory of Open Access Journals (Sweden)

    Filip Rezac

    2010-01-01

    Full Text Available Delay in VoIP technology is very unpleasant issue and therefore a voice packets prioritization must be ensured. To maintain the high call quality a maximum information delivery time from the sender to the recipient is set to 150 ms. This paper focuses on the design of a mathematical model of end-to-end delay of a VoIP connection, in particular on a delay variation. It describes all partial delay components and mechanisms, their generation, facilities and mathematical formulations. A new approach to the delay variation model is presented and its validation has been done by experimention.

  14. H∞ State Feedback Delay-dependent Control for Discrete Systems with Multi-time-delay

    Institute of Scientific and Technical Information of China (English)

    Bai-Da Qu

    2005-01-01

    In this paper,H∞ state feedback control with delay information for discrete systems with multi-time-delay is discussed. Making use of linear matrix inequality (LMI) approach, a time-delay-dependent criterion for a discrete system with multi-time-delay to satisfy H∞ performance indices is induced, and then a strategy for H∞ state feedback control with delay values for plant with multi-time-delay is obtained. By solving corresponding LMI, a delay-dependent state feedback controller satisfying H∞ performance indices is designed. Finally, a simulation example demonstrates the validity of the proposed approach.

  15. The go/no-go priming task: automatic evaluation and categorisation beyond response interference.

    Science.gov (United States)

    de Paula Couto, Maria Clara P; Wentura, Dirk

    2017-08-01

    The response-window version of a go/no-go (GNG) response priming task is introduced using both evaluative (Experiment 1) and animacy decision (Experiment 2). In each trial a cue indicates which target category should lead to a key-press. The target is preceded by either a congruent or incongruent prime. The standard priming task was added as well. Both tasks yielded robust priming effects. However, they differed regarding a signature of response activation paradigms, that is, the Gratton effect (i.e. smaller priming effects following incongruent trials compared to congruent trials), which is present in the standard task but absent in the GNG task. This indicates that effects found with the GNG task are caused by different processes compared to the standard task. Experiment 3 tested an alternative account to explain priming effects in the GNG task. By manipulating response biases, Experiment 3 provides evidence for this account.

  16. Asymptotic Delay Analysis for Cross-Layer Delay-Based Routing in Ad Hoc Networks

    Directory of Open Access Journals (Sweden)

    Philippe Jacquet

    2007-01-01

    Full Text Available This paper addresses the problem of the evaluation of the delay distribution via analytical means in IEEE 802.11 wireless ad hoc networks. We show that the asymptotic delay distribution can be expressed as a power law. Based on the latter result, we present a cross-layer delay estimation protocol and we derive new delay-distribution-based routing algorithms, which are well adapted to the QoS requirements of real-time multimedia applications. In fact, multimedia services are not sensitive to average delays, but rather to the asymptotic delay distributions. Indeed, video streaming applications drop frames when they are received beyond a delay threshold, determined by the buffer size. Although delay-distribution-based routing is an NP-hard problem, we show that it can be solved in polynomial time when the delay threshold is large, because of the asymptotic power law distribution of the link delays.

  17. Delay-Dependent Observers for Uncertain Nonlinear Time-Delay Systems

    Directory of Open Access Journals (Sweden)

    Dongmei Yan

    2013-05-01

    Full Text Available This paper is concerned with the observer design problem for a class of discrete-time uncertain nonlinear systems with time-varying delay. The nonlinearities are assumed to satisfy global Lipschitz conditions which appear in both the state and measurement equations. The uncertainties are assumed to be time-varying but norm-bounded. Two Luenberger-like observers are proposed. One is delay observer and the other is delay-free observer. The delay observer which has an internal time delay is applicable when the time delay is known. The delay-free observer which does not use delayed information is especially applicable when the time delay is not known explicitly. Delay-dependent conditions for the existences of these two observers are derived based on Lyapunpv functional approach. Based on these conditions, the observer gains are obtained using the cone complementarity linearization algorithm. Finally, a numerical example is given to illustrate the effectiveness of the proposed method.

  18. Precise delay measurement through combinatorial logic

    Science.gov (United States)

    Burke, Gary R. (Inventor); Chen, Yuan (Inventor); Sheldon, Douglas J. (Inventor)

    2010-01-01

    A high resolution circuit and method for facilitating precise measurement of on-chip delays for FPGAs for reliability studies. The circuit embeds a pulse generator on an FPGA chip having one or more groups of LUTS (the "LUT delay chain"), also on-chip. The circuit also embeds a pulse width measurement circuit on-chip, and measures the duration of the generated pulse through the delay chain. The pulse width of the output pulse represents the delay through the delay chain without any I/O delay. The pulse width measurement circuit uses an additional asynchronous clock autonomous from the main clock and the FPGA propagation delay can be displayed on a hex display continuously for testing purposes.

  19. Estimation of time delay by coherence analysis

    CERN Document Server

    Govindan, R B; Kopper, F; Claussen, J C; Deuschl, G

    2004-01-01

    Using coherence analysis (which is an extensively used method to study the correlations in frequency domain, between two simultaneously measured signals) we estimate the time delay between two signals. This method is suitable for time delay estimation of narrow band coherence signals for which the conventional methods cannot be reliably applied. We show by analysing coupled R\\"ossler attractors with a known delay, that the method yields satisfactory results. Then, we apply this method to human pathologic tremor. The delay between simultaneously measured traces of Electroencephalogram (EEG) and Electromyogram (EMG) data of subjects with essential hand tremor is calculated. We find that there is a delay of 11-27 milli-seconds ($ms$) between the tremor correlated parts (cortex) of the brain (EEG) and the trembling hand (EMG) which is in agreement with the experimentally observed delay value of 15 $ms$ for the cortico-muscular conduction time. By surrogate analysis we calculate error-bars of the estimated delay.

  20. Synchronization of time-delay chaotic systems on small-world networks with delayed coupling

    Institute of Scientific and Technical Information of China (English)

    Qi Wei; Wang Ying-Hai

    2009-01-01

    By using the well-known Ikeda model as the node dynamics,this paper studies synchronization of time-delay systems on small-world networks where the connections between units involve time delays.It shows that,in contrast with the undelayed case,networks with delays can actually synchronize more easily.Specifically,for randomly distributed delays,time-delayed mutual coupling suppresses the chaotic behaviour by stabilizing a fixed point that is unstable for the uncoupled dynamical system.

  1. Time-delay feedback control in a delayed dynamical chaos system and its applications

    Institute of Scientific and Technical Information of China (English)

    Ye Zhi-Yong; Yang Guang; Deng Cun-Bing

    2011-01-01

    The feedback control of a delayed dynamical system, which also includes various chaotic systems with time delays, is investigated. On the basis of stability analysis of a nonautonomons system with delays, some simple yet less conservative criteria are obtained for feedback control in a delayed dynamical system. Finally, the theoretical result is applied to a typical class of chaotic Lorenz system and Chua circuit with delays. Numerical simulations are also given to verify the theoretical results.

  2. [Delayed post effort muscle soreness].

    Science.gov (United States)

    Coudreuse, J M; Dupont, P; Nicol, C

    2004-08-01

    Muscle intolerance to exercise may result from different processes. Diagnosis involves confirming first the source of pain, then potential pathological myalgia. Delayed-onset muscle soreness (DOMS), commonly referred as tiredness, occurs frequently in sport. DOMS usually develops 12-48 h after intensive and/or unusual eccentric muscle action. Symptoms usually involve the quadriceps muscle group but may also affect the hamstring and triceps surae groups. The muscles are sensitive to palpation, contraction and passive stretch. Acidosis, muscle spasm and microlesions in both connective and muscle tissues may explain the symptoms. However, inflammation appears to be the most common explanation. Interestingly, there is strong evidence that the progression of the exercise-induced muscle injury proceeds no further in the absence of inflammation. Even though unpleasant, DOMS should not be considered as an indicator of muscle damage but, rather, a sign of the regenerative process, which is well known to contribute to the increased muscle mass. DOMS can be associated with decreased proprioception and range of motion, as well as maximal force and activation. DOMS disappears 2-10 days before complete functional recovery. This painless period is ripe for additional joint injuries. Similarly, if some treatments are well known to attenuate DOMS, none has been demonstrated to accelerate either structural or functional recovery. In terms of the role of the inflammatory process, these treatments might even delay overall recovery.

  3. Elite athletes and pubertal delay.

    Science.gov (United States)

    Kapczuk, Karina

    2017-10-01

    Intensive physical training and participation in competitive sports during childhood and early adolescence may affect athletes' pubertal development. On the other hand, pubertal timing, early or late, may impact on an athlete selection for a particular sport. Genetic predisposition, training load, nutritional status and psychological stress determine athletes' pubertal timing. Athletes that practice esthetic sports, especially gymnasts, are predisposed to a delay in pubertal development. The growing evidence indicates that energy deficiency, not a systemic training per se, plays a crucial role in the pathogenesis of functional hypothalamic hypogonadism in female athletes. Metabolic and psychologic stress activate hypothalamic-pituitary-adrenal axis and suppress hypothalamic-pituitary-ovarian axis. Female athletes who do not begin secondary sexual development by the age of 14 or menstruation by the age of 16 warrant a comprehensive evaluation and a targeted treatment. Somatic growth and sexual maturation of elite female athletes are largely sport-specific since each sport favors a particular somatotype and requires a specific training. Chronic negative energy balance resulting from a systemic physical training and inadequate energy intake may delay pubertal development in elite athletes. Youth athletes, especially those engaged in competitive sports that emphasize prepubertal or lean appearance, are at risk of developing relative energy deficiency in sport associated with disordered eating or eating disorders. Management strategies should address the complex conditions underlying functional hypothalamic hypogonadism.

  4. Task Analyses for Difficult-to-Assess Collective Tasks

    Science.gov (United States)

    2014-02-01

    Counterintelligence and Human Intelligence Analysis and Production (34-4-1305) • Conduct Counterintelligence and Human Intelligence Analysis (34-4...Research Product 2014-05 Task Analyses for Difficult-to-Assess Collective Tasks Jonathan J. Bryson Rachel D. Barney...Christina K. Curnow Trevor M. Conrad Arnold L. Leonard Heidi Keller-Glaze ICF International Jennifer S. Tucker Christopher L. Vowels

  5. Trading Later Rewards for Current Pleasure: Pornography Consumption and Delay Discounting.

    Science.gov (United States)

    Negash, Sesen; Sheppard, Nicole Van Ness; Lambert, Nathaniel M; Fincham, Frank D

    2016-01-01

    Internet pornography is a multi-billion-dollar industry that has grown increasingly accessible. Delay discounting involves devaluing larger, later rewards in favor of smaller, more immediate rewards. The constant novelty and primacy of sexual stimuli as particularly strong natural rewards make Internet pornography a unique activator of the brain's reward system, thereby having implications for decision-making processes. Based on theoretical studies of evolutionary psychology and neuroeconomics, two studies tested the hypothesis that consuming Internet pornography would relate to higher rates of delay discounting. Study 1 used a longitudinal design. Participants completed a pornography use questionnaire and a delay discounting task at Time 1 and then again four weeks later. Participants reporting higher initial pornography use demonstrated a higher delay discounting rate at Time 2, controlling for initial delay discounting. Study 2 tested for causality with an experimental design. Participants were randomly assigned to abstain from either their favorite food or pornography for three weeks. Participants who abstained from pornography use demonstrated lower delay discounting than participants who abstained from their favorite food. The finding suggests that Internet pornography is a sexual reward that contributes to delay discounting differently than other natural rewards. Theoretical and clinical implications of these studies are highlighted.

  6. HL-LHC alternatives

    CERN Document Server

    Tomás, R; White, S

    2014-01-01

    The HL-LHC parameters assume unexplored regimes for hadron colliders in various aspects of accelerator beam dynamics and technology. This paper reviews three alternatives that could potentially improve the LHC performance: (i) the alternative filling scheme 8b+4e, (ii) the use of a 200 MHz RF system in the LHC and (iii) the use of proton cooling methods to reduce the beam emittance (at top energy and at injection). The alternatives are assessed in terms of feasibility, pros and cons, risks versus benefits and the impact on beam availability.

  7. Alternative loop rings

    CERN Document Server

    Goodaire, EG; Polcino Milies, C

    1996-01-01

    For the past ten years, alternative loop rings have intrigued mathematicians from a wide cross-section of modern algebra. As a consequence, the theory of alternative loop rings has grown tremendously. One of the main developments is the complete characterization of loops which have an alternative but not associative, loop ring. Furthermore, there is a very close relationship between the algebraic structures of loop rings and of group rings over 2-groups. Another major topic of research is the study of the unit loop of the integral loop ring. Here the interaction between loop rings and group ri

  8. Pre-stimulus EEG effects related to response speed, task switching and upcoming response hand

    NARCIS (Netherlands)

    Gladwin, T.E.; Lindsen, J.P.; Jong, R. de

    2006-01-01

    The task-switching paradigm provides an opportunity to study whether oscillatory relations in neuronal activity are involved in switching between and maintaining task sets. The EEG of subjects performing an alternating runs [Rogers, R.D., Monsell, S., 1995. Costs of a predictable switch between simp

  9. Continuous neural identifier for uncertain nonlinear systems with time delays in the input signal.

    Science.gov (United States)

    Alfaro-Ponce, M; Argüelles, A; Chairez, I

    2014-12-01

    Time-delay systems have been successfully used to represent the complexity of some dynamic systems. Time-delay is often used for modeling many real systems. Among others, biological and chemical plants have been described using time-delay terms with better results than those models that have not consider them. However, getting those models represented a challenge and sometimes the results were not so satisfactory. Non-parametric modeling offered an alternative to obtain suitable and usable models. Continuous neural networks (CNN) have been considered as a real alternative to provide models over uncertain non-parametric systems. This article introduces the design of a specific class of non-parametric model for uncertain time-delay system based on CNN considering the so-called delayed learning laws analysis. The convergence analysis as well as the learning laws were produced by means of a Lyapunov-Krasovskii functional. Three examples were developed to demonstrate the effectiveness of the modeling process forced by the identifier proposed in this study. The first example was a simple nonlinear model used as benchmark example. The second example regarded the human immunodeficiency virus dynamic behavior is used to show the performance of the suggested non-parametric identifier based on CNN for no fictitious neither academic models. Finally, a third example describing the evolution of hepatitis B virus served to test the identifier presented in this study and was also useful to provide evidence of its superior performance against a non-delayed identifier based on CNN.

  10. Development of a new Delayed Memory Index for the WMS-III.

    Science.gov (United States)

    Tulsky, David S; Chelune, Gordon J; Price, Larry R

    2004-06-01

    This paper presents the Delayed Memory Index (DMI) as an alternative to the General Memory Index (GMI) of the Weschler Memory Scale-Third Edition (WMS-III). The WMS-III Immediate Memory Index (IMI) and the GMI are not parallel in structure, making a direct comparison between these index scores (i.e., immediate vs. delayed memory variables) difficult. The IMI is composed of the sum of scaled scores of four subtests (Logical Memory I, Verbal Paired Associates I, Faces I, and Family Pictures I) while the GMI is composed of the sum of scaled scores of five subtests (Logical Memory II, Verbal Paired Associates II, Faces II, Family Pictures II and Auditory Recognition Delayed). Inclusion of Auditory Recognition Delayed in the GMI is also problematic as it is highly skewed and limited by extreme ceiling effects (see Tulsky, Chiaravalloti, Palmer, & Chelune, 2003). To remedy these problems, we present a new index score that does not include auditory recognition, the Delayed Memory Index. Normative tables for the new Delayed Memory Index based on the inclusion of the Faces subtest, or alternatively the Visual Reproduction subtest, are presented, and initial estimates of their psychometric properties are described.

  11. Bayesian Alternation During Tactile Augmentation

    Directory of Open Access Journals (Sweden)

    Caspar Mathias Goeke

    2016-10-01

    Full Text Available A large number of studies suggest that the integration of multisensory signals by humans is well described by Bayesian principles. However, there are very few reports about cue combination between a native and an augmented sense. In particular, we asked the question whether adult participants are able to integrate an augmented sensory cue with existing native sensory information. Hence for the purpose of this study we build a tactile augmentation device. Consequently, we compared different hypotheses of how untrained adult participants combine information from a native and an augmented sense. In a two-interval forced choice (2 IFC task, while subjects were blindfolded and seated on a rotating platform, our sensory augmentation device translated information on whole body yaw rotation to tactile stimulation. Three conditions were realized: tactile stimulation only (augmented condition, rotation only (native condition, and both augmented and native information (bimodal condition. Participants had to choose one out of two consecutive rotations with higher angular rotation. For the analysis, we fitted the participants’ responses with a probit model and calculated the just notable difference (JND. Then we compared several models for predicting bimodal from unimodal responses. An objective Bayesian alternation model yielded a better prediction (χred2 = 1.67 than the Bayesian integration model (χred2= 4.34. Slightly higher accuracy showed a non-Bayesian winner takes all model (χred2= 1.64, which either used only native or only augmented values per subject for prediction. However the performance of the Bayesian alternation model could be substantially improved (χred2= 1.09 utilizing subjective weights obtained by a questionnaire. As a result, the subjective Bayesian alternation model predicted bimodal performance most accurately among all tested models. These results suggest that information from augmented and existing sensory modalities in

  12. Delaying Trains of Short Light Pulses in WGM Resonators

    Science.gov (United States)

    Matsko, Andrey; Iltchenko, Vladimir; Strekalov, Dmitry; Savchenkov, Anatoliy; Maleki, Lute

    2008-01-01

    Suitably configured whispering-gallery-mode (WGM) optical resonators have been proposed as delay lines for trains of short light pulses. Until now, it has been common practice to implement an optical delay line as a coiled long optical fiber, which is bulky and tends to be noisy. An alternative has been to implement an optical delay line as a coupled-resonator optical waveguide (a chain of coupled optical resonators), which is compact but limits the width of the pulse spectrum to the width of an optical resonance and thereby places a lower limit on the duration of a pulse. In contrast, a delay line according to the proposal could be implemented as a single WGM resonator, and the pulses delayed by the resonator could be so short that their spectral widths could greatly exceed the spectral width of any single resonance. The proposal emerged from theoretical and experimental studies of the propagation of a pulse train in a WGM resonator. An important element of the theoretical study was recognition that the traditional definition of group velocity in effect, the velocity of a single pulse comprising a packet of waves propagating in a medium, the responsivity of which is a monotonous function of frequency does not necessarily apply in the case of a WGM resonator or other medium having a spectrum consisting of discrete resonance peaks at different frequencies. A new definition of group velocity, applicable to a train of pulses propagating in such a medium, was introduced and found to lead to the discovery of previously unknown features of propagation. Notably, it was found that in a micro - sphere optical resonator that supports a suitable combination of WGM modes, the group velocity for a train of light pulses could be positive, zero, or negative. A positive group velocity could be so small that the delay could be much longer than the ring-down time of the resonator; a delay of such great length is impossible for a single pulse interacting with either a linearly

  13. Temporal dynamics of interference in Simon and Eriksen tasks considered within the context of a dual-process model.

    Science.gov (United States)

    Mansfield, Karen L; van der Molen, Maurits W; Falkenstein, Michael; van Boxtel, Geert J M

    2013-08-01

    Behavioral and brain potential measures were employed to compare interference in Eriksen and Simon tasks. Assuming a dual-process model of interference elicited in speeded response tasks, we hypothesized that only lateralized stimuli in the Simon task induce fast S-R priming via direct unconditional processes, while Eriksen interference effects are induced later via indirect conditional processes. Delays to responses for incongruent trials were indeed larger in the Eriksen than in the Simon task. Only lateralized stimuli in the Simon task elicited early S-R priming, maximal at parietal areas. Incongruent flankers in the Eriksen task elicited interference later, visible as a lateralized N2. Eriksen interference also elicited an additional component (N350), which accounted for the larger behavioral interference effects in the Eriksen task. The findings suggest that interference and its resolution involve different processes for Simon and Eriksen tasks.

  14. Reward-based decision making in pathological gambling: the roles of risk and delay.

    Science.gov (United States)

    Wiehler, Antonius; Peters, Jan

    2015-01-01

    Pathological gambling (PG) is a non-substance based addiction that shares many behavioral and neural features with substance based addictions. However, in PG behavioral and neural changes are unlikely to be confounded by effects of acute or chronic drug exposure. Changes in reward based decision-making in particular increases in impulsivity are hallmark features of addictions. Here we review studies in PG that applied three reward-related decision tasks: the Iowa Gambling Task, probability discounting and delay discounting. We discuss the findings and focus on the impact of addiction severity and the relation of effects to impulsivity measures. While there is evidence that PGs differ from healthy controls on all three tasks, there is only little support for a further modulation of impairments by addiction severity. Conceptually, delay discounting is related to impulsivity measures and findings in this task show a considerable correlation with e.g. questionnaire-based measures of impulsivity. Taken together, impairments in PG on these three tasks are relatively well replicated, although impairments appear to be largely uncorrelated between tasks. An important next step will be to conceptualize a process-based account of behavioral impairments in PG.

  15. Designing reading tasks to foster critical thinking Designing reading tasks to foster critical thinking

    Directory of Open Access Journals (Sweden)

    Leda Maria Braga Tomitch

    2008-04-01

    Full Text Available What else is there besides multiple choice exercises, questions or true-false statements? What kind of readers do we EFL/ESL teachers, want to develop? Fortunately, there are alternative possibilities for designing reading activities which, besides being more interesting and fun for the students than the traditional tasks, can help develop more active and critical readers. A search in EFL/ESL reading textbooks has revealed that the most frequently encountered types of reading activities are comprehension questions, multiple-choice exercises, and true-false statements (Tomitch, in press a. These tasks have been used throughout the history of language teaching, and one must agree that they have their merits. However, there are reasons why they should not be used as the only source of activity in the classroom. What else is there besides multiple choice exercises, questions or true-false statements? What kind of readers do we EFL/ESL teachers, want to develop? Fortunately, there are alternative possibilities for designing reading activities which, besides being more interesting and fun for the students than the traditional tasks, can help develop more active and critical readers. A search in EFL/ESL reading textbooks has revealed that the most frequently encountered types of reading activities are comprehension questions, multiple-choice exercises, and true-false statements (Tomitch, in press a. These tasks have been used throughout the history of language teaching, and one must agree that they have their merits. However, there are reasons why they should not be used as the only source of activity in the classroom.

  16. Vaginal dryness alternative treatments

    Science.gov (United States)

    Alternative treatments for vaginal dryness ... Question: Is there a drug-free treatment for vaginal dryness? Answer: There are many causes of vaginal dryness . It may be caused by reduced estrogen level, infection, medicines, and ...

  17. Breast Reconstruction Alternatives

    Science.gov (United States)

    ... Breast Reconstruction Surgery Breast Cancer Breast Reconstruction Surgery Breast Reconstruction Alternatives Some women who have had a ... chest. What if I choose not to get breast reconstruction? Some women decide not to have any ...

  18. Alternative disinfectant water treatments

    Science.gov (United States)

    Alternative disinfestant water treatments are disinfestants not as commonly used by the horticultural industry. Chlorine products that produce hypochlorous acid are the main disinfestants used for treating irrigation water. Chlorine dioxide will be the primary disinfestant discussed as an alternativ...

  19. Seal design alternatives study

    Energy Technology Data Exchange (ETDEWEB)

    Van Sambeek, L.L. [RE/SPEC Inc., Rapid City, SD (US); Luo, D.D.; Lin, M.S.; Ostrowski, W.; Oyenuga, D. [Parsons Brinckerhoff Quade & Douglas, Inc., San Francisco, CA (US)

    1993-06-01

    This report presents the results from a study of various sealing alternatives for the WIPP sealing system. Overall, the sealing system has the purpose of reducing to the extent possible the potential for fluids (either gas or liquid) from entering or leaving the repository. The sealing system is divided into three subsystems: drift and panel seals within the repository horizon, shaft seals in each of the four shafts, and borehole seals. Alternatives to the baseline configuration for the WIPP seal system design included evaluating different geometries and schedules for seal component installations and the use of different materials for seal components. Order-of-magnitude costs for the various alternatives were prepared as part of the study. Firm recommendations are not presented, but the advantages and disadvantages of the alternatives are discussed. Technical information deficiencies are identified and studies are outlined which can provide required information.

  20. Alternative fuel information sources

    Energy Technology Data Exchange (ETDEWEB)

    1994-06-01

    This short document contains a list of more than 200 US sources of information (Name, address, phone number, and sometimes contact) related to the use of alternative fuels in automobiles and trucks. Electric-powered cars are also included.

  1. Photobiomodulation delays the onset of skeletal muscle fatigue in a dose-dependent manner.

    Science.gov (United States)

    Larkin-Kaiser, Kelly A; Borsa, Paul A; Baweja, Harsimran S; Moore, Molly A; Tillman, Mark D; George, Steven Z; Christou, Evangelos A

    2016-09-01

    Photobiomodulation (PBM) therapy has been implicated as an effective ergogenic aid to delay the onset of muscle fatigue. The purpose of this study was to examine the dose-response ergogenic properties of PBM therapy and its ability to prolong time to task failure by enhancing muscle activity and delaying the onset of muscle fatigue using a static positioning task. Nine participants (24.3 ± 4.9 years) received three doses of near-infrared (NIR) light therapy randomly on three separate sessions (sham, 240, and 480 J). For the positioning task, participants held a 30 % one-repetition maximum (1-RM) load using the index finger until volitional fatigue. Surface electromyography (sEMG) of the first dorsal interosseous muscle was recorded for the length of the positioning task. Outcomes included time to task failure (TTF), muscle fatigue, movement accuracy, motor output variability, and muscle activity (sEMG). The 240-J dose significantly extended TTF by 26 % (p = 0.032) compared with the sham dose. TTF for the 240-J dose was strongly associated with a decrease in muscle fatigue (R (2) = 0.54, p = 0.024). Our findings show that a 240-J dose of NIR light therapy is efficacious in delaying the onset and extent of muscle fatigue during submaximal isometric positioning tasks. Our findings suggest that NIR light therapy may be used as an ergogenic aid during functional tasks or post-injury rehabilitation.

  2. The absence of numbers to express the amount may affect delay discounting with humans.

    Science.gov (United States)

    Reyes-Huerta, Hugo E; Dos Santos, Cristiano V

    2016-09-01

    Human delay discounting is usually studied with experimental protocols that use symbols to express delay and amount. In order to further understand discounting, we evaluated whether the absence of numbers to represent reward amounts affects discount rate in general, and whether the magnitude effect is generalized to nonsymbolic situations in particular. In Experiment 1, human participants were exposed to a delay-discounting task in which rewards were presented using dots to represent monetary rewards (nonsymbolic); under this condition the magnitude effect did not occur. Nevertheless, the magnitude effect was observed when equivalent reward amounts were presented using numbers (symbolic). Moreover, in estimation tasks, magnitude increments produced underestimation of large amounts. In Experiment 2, participants were exposed only to the nonsymbolic discounting task and were required to estimate reward amounts in each trial. Consistent with Experiment 1, the absence of numbers representing reward amounts produced similar discount rates of small and large rewards. These results suggest that value of nonsymbolic rewards is a nonlinear function of amount and that value attribution depends on perceived difference between the immediate and the delayed nonsymbolic rewards.

  3. Delay discounting, risk-taking, and rejection sensitivity among individuals with Internet and Video Gaming Disorders

    Science.gov (United States)

    Weinstein, Aviv; Abu, Hodaya Ben; Timor, Ayelet; Mama, Yaniv

    2016-01-01

    Background and aims There is a previous evidence for impulsivity in individuals with Internet and Video Gaming Disorders. The aim of this study was to examine whether Internet and video game addictions are associated with experiential delay discounting, risk-taking, and sensitivity to social rejection using computerized tasks and questionnaires. Methods Twenty participants (mean age 24, SD = 1.55) with high score on the Problematic Online Gaming Questionnaire (POGQ) were compared with 20 participants (mean age 24.8, SD = 1.34) with low score on the POGQ. They performed on computerized Balloon Analog Risk Task and Experiential Delay discounting Task (EDT), and filled in the sensitivity to social rejection questionnaire. Results Participants with high POGQ scores had lower measures of delay discounting, higher measures of risk-taking, and higher measures of sensitivity to social rejection compared with participants with low POGQ scores. Discussion The results of this study support the previous evidence of risk-taking and provide new evidence for difficulties in delay discounting and sensitivity to social rejection among those who score high on Internet and video games. Conclusions The results suggest that Internet- and video game-addicted individuals seek immediate gratification and cannot wait for later reward. Furthermore, these individuals spend time in the virtual world, where they feel safe, and avoid social interactions presumably due to fears of social rejection. PMID:27958761

  4. Approximate Controllability of Semilinear Neutral Stochastic Integrodifferential Inclusions with Infinite Delay

    Directory of Open Access Journals (Sweden)

    Meili Li

    2015-01-01

    Full Text Available The approximate controllability of semilinear neutral stochastic integrodifferential inclusions with infinite delay in an abstract space is studied. Sufficient conditions are established for the approximate controllability. The results are obtained by using the theory of analytic resolvent operator, the fractional power theory, and the theorem of nonlinear alternative for Kakutani maps. Finally, an example is provided to illustrate the theory.

  5. A Comparison of Simultaneous Prompting and Constant Time Delay Procedures in Teaching State Capitals

    Science.gov (United States)

    Head, Kenneth David; Collins, Belva C.; Schuster, John W.; Ault, Melinda Jones

    2011-01-01

    This investigation compared the effectiveness and efficiency of constant time delay (CTD) and simultaneous prompting (SP) procedures in teaching discrete social studies facts to 4 high school students with learning and behavior disorders using an adapted alternating treatments design nested within a multiple probe design. The results indicated…

  6. Simultaneous and Delayed Video Modeling: An Examination of System Effectiveness and Student Preferences

    Science.gov (United States)

    Taber-Doughyt, Teresa; Patton, Scott E.; Brennan, Stephanie

    2009-01-01

    The effectiveness of simultaneous and delayed video modeling when used by three middle-school students with moderate intellectual disabilities was examined. Alternating between modeling systems, students were taught to use the public library computer to locate specific book call numbers and use the Dewey Decimal Classification System to locate…

  7. Conversion of linear time-invariant time-delay feedback systems into delay-differential equations with commensurate delays

    Science.gov (United States)

    Yamazaki, Tatsuya; Hagiwara, Tomomichi

    2014-08-01

    A new stability analysis method of time-delay systems (TDSs) called the monodromy operator approach has been studied under the assumption that a TDS is represented as a time-delay feedback system consisting of a finite-dimensional linear time-invariant (LTI) system and a pure delay. For applying this approach to TDSs described by delay-differential equations (DDEs), the problem of converting DDEs into representation as time-delay feedback systems has been studied. With regard to such a problem, it was shown that, under discontinuous initial functions, it is natural to define the solutions of DDEs in two different ways, and the above conversion problem was solved for each of these two definitions. More precisely, the solution of a DDE was represented as either the state of the finite-dimensional part of a time-delay feedback system or a part of the output of another time-delay feedback system, depending on which definition of the DDE solution one is talking about. Motivated by the importance in establishing a thorough relationship between time-delay feedback systems and DDEs, this paper discusses the opposite problem of converting time-delay feedback systems into representation as DDEs, including the discussions about the conversion of the initial conditions. We show that the state of (the finite-dimensional part of) a time-delay feedback system can be represented as the solution of a DDE in the sense of one of the two definitions, while its 'essential' output can be represented as that of another DDE in the sense of the other type of definition. Rigorously speaking, however, it is also shown that the latter representation is possible regardless of the initial conditions, while some initial condition could prevent the conversion into the former representation. This study hence establishes that the representation of TDSs as time-delay feedback systems possesses higher ability than that with DDEs, as description methods for LTI TDSs with commensurate delays.

  8. Mixed delay-independent/delay-dependent stability of uncertain linear time-delayed systems

    Institute of Scientific and Technical Information of China (English)

    LI Wenlin; DONG Rui

    2004-01-01

    @@ Consider uncertain linear time delay systems described by the following state equation: x(t)=[A0+Δ A0(t)]x(t)+∑ri=1[Ai+ΔAi(t)]x(t-τi).(1) x(t)=(t)t∈[-,0];=maxri=1{τi}(2) where Δ A0(*) and Δ Ai(*)(i=1,…,r) are real matrix functions.Δ Ai(t)=LiFi(t)Ei,ΔA0(t)=L0F0(t)E0, where Li,Ei are known real constant matrices and Fi(t) are unknown real time-varying matrices with Lebesgue measurable elements satisfying ‖Fi(t)‖I,t(i=0,1,…,r). In this note, we develop the methods of robust stability which is dependent on the size of some delays but independent on the size of the others and is based on the solution of linear matrix inequalities.

  9. Putting Mathematical Tasks into Context

    Science.gov (United States)

    Nagle, Courtney R.; Styers, Jodie L.

    2015-01-01

    Although many factors affect students' mathematical activity during a lesson, the teacher's selection and implementation of tasks is arguably the most influential in determining the level of student engagement. Mathematical tasks are intended to focus students' attention on a particular mathematical concept and it is the careful developing and…

  10. Human-System task integration

    NARCIS (Netherlands)

    Schraagen, J.M.C.

    2005-01-01

    The Dutch Ministry of Defence research programme Human-System Task Integration aims at acquiring knowledge for the optimal cooperation between human and computer, under the following constraints: freedom of choice in decisions to automate and multiple, dynamic task distributions. This paper describe

  11. Designing for dynamic task allocation

    NARCIS (Netherlands)

    Dongen, C.J.G. van; Maanen, P.P. van

    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 co

  12. Task modeling for collaborative authoring

    NARCIS (Netherlands)

    Veer, van der Gerrit; Kulyk, Olga; Vyas, Dhaval; Kubbe, Onno; Ebert, Achim; Dittmar, A.; Forbrig, P.

    2011-01-01

    Motivation –Task analysis for designing modern collaborative work needs a more fine grained approach. Especially in a complex task domain, like collaborative scientific authoring, when there is a single overall goal that can only be accomplished only by collaboration between multiple roles, each req

  13. Virtual unit delay for digital frequency adaptive T/4 delay phase-locked loop system

    DEFF Research Database (Denmark)

    Yang, Yongheng; Zhou, Keliang; Blaabjerg, Frede

    2016-01-01

    -controller/processor with a fixed sampling rate considering the cost and complexity, where the number of unit delays that have been adopted should be an integer. For instance, in conventional digital control systems, a single-phase T/4 Delay Phase-Locked Loop (PLL) system takes 50 unit delays (i.e., in a 50-Hz system...... Delay PLL system should be done in its implementation. This process will result in performance degradation in the digital control system, as the exactly required number of delays is not realized. Hence, in this paper, a Virtual Unit Delay (VUD) has been proposed to address such challenges to the digital...... T/4 Delay PLL system. The proposed VUD adopts linear interpolation polynomial to approximate the fractional delay induced by the varying grid frequency in such a way that the control performance is enhanced. The proposed VUD has been demonstrated on a digitally controlled T/4 Delay PLL system...

  14. Variable-delay feedback control of unstable steady states in retarded time-delayed systems

    CERN Document Server

    Gjurchinovski, Aleksandar; 10.1103/PhysRevE.81.016209

    2010-01-01

    We study the stability of unstable steady states in scalar retarded time-delayed systems subjected to a variable-delay feedback control. The important aspect of such a control problem is that time-delayed systems are already infinite-dimensional before the delayed feedback control is turned on. When the frequency of the modulation is large compared to the system's dynamics, the analytic approach consists of relating the stability properties of the resulting variable-delay system with those of an analogous distributed delay system. Otherwise, the stability domains are obtained by a numerical integration of the linearized variable-delay system. The analysis shows that the control domains are significantly larger than those in the usual time-delayed feedback control, and that the complexity of the domain structure depends on the form and the frequency of the delay modulation.

  15. Post-CTS Delay Insertion

    Directory of Open Access Journals (Sweden)

    Jianchao Lu

    2010-01-01

    clock skew operation is performed only at the clock sinks in order to preserve the structure and the optimizations implemented in the clock tree synthesis stage. The methodology is implemented as a linear programming model amenable to two design objectives: fixing timing violations or optimizing the clock period. Experimental results show that the clock networks of the largest ISCAS'89 circuits can be corrected post-CTS to resolve the timing conflicts in approximately 90% of the circuits with minimal delay insertion (0.159  ×  clock period per clock path on average. It is also shown that the majority of the clock period improvement achievable through unrestricted clock skew scheduling are obtained through very limited insertion (≈43% average improvement through 10% of max insertion.

  16. Transition delay using control theory.

    Science.gov (United States)

    Bagheri, S; Henningson, D S

    2011-04-13

    This review gives an account of recent research efforts to use feedback control for the delay of laminar-turbulent transition in wall-bounded shear flows. The emphasis is on reducing the growth of small-amplitude disturbances in the boundary layer using numerical simulations and a linear control approach. Starting with the application of classical control theory to two-dimensional perturbations developing in spatially invariant flows, flow control based on control theory has progressed towards more realistic three-dimensional, spatially inhomogeneous flow configurations with localized sensing/actuation. The development of low-dimensional models of the Navier-Stokes equations has played a key role in this progress. Moreover, shortcomings and future challenges, as well as recent experimental advances in this multi-disciplinary field, are discussed.

  17. A behavioral economic analysis of texting while driving: Delay discounting processes.

    Science.gov (United States)

    Hayashi, Yusuke; Miller, Kimberly; Foreman, Anne M; Wirth, Oliver

    2016-12-01

    The purpose of the present study was to examine an impulsive decision-making process underlying texting while driving from a behavioral economic perspective. A sample of 108 college students completed a novel discounting task that presented participants with a hypothetical scenario in which, after receiving a text message while driving, they rated the likelihood of replying to a text message immediately versus waiting to reply for a specific period of time. Participants also completed a delay discounting task in which they made repeated hypothetical choices between obtaining a larger amount of money available after a delay and an equal or lesser amount of money available immediately. The results show that the duration of the delay is a critical variable that strongly determines whether participants choose to wait to reply to a text message, and that the decrease in the likelihood of waiting as a function of delay is best described by a hyperbolic delay discounting function. The results also show that participants who self-reported higher frequency of texting while driving discounted the opportunity to reply to a text message at greater rates, whereas there was no relation between the rates of discounting of hypothetical monetary rewards and the frequency of texting while driving. The results support the conclusion that texting while driving is fundamentally an impulsive choice.

  18. Significance of Joint Features Derived from the Modified Group Delay Function in Speech Processing

    Directory of Open Access Journals (Sweden)

    Murthy Hema A

    2007-01-01

    Full Text Available This paper investigates the significance of combining cepstral features derived from the modified group delay function and from the short-time spectral magnitude like the MFCC. The conventional group delay function fails to capture the resonant structure and the dynamic range of the speech spectrum primarily due to pitch periodicity effects. The group delay function is modified to suppress these spikes and to restore the dynamic range of the speech spectrum. Cepstral features are derived from the modified group delay function, which are called the modified group delay feature (MODGDF. The complementarity and robustness of the MODGDF when compared to the MFCC are also analyzed using spectral reconstruction techniques. Combination of several spectral magnitude-based features and the MODGDF using feature fusion and likelihood combination is described. These features are then used for three speech processing tasks, namely, syllable, speaker, and language recognition. Results indicate that combining MODGDF with MFCC at the feature level gives significant improvements for speech recognition tasks in noise. Combining the MODGDF and the spectral magnitude-based features gives a significant increase in recognition performance of 11% at best, while combining any two features derived from the spectral magnitude does not give any significant improvement.

  19. Significance of Joint Features Derived from the Modified Group Delay Function in Speech Processing

    Directory of Open Access Journals (Sweden)

    Rajesh M. Hegde

    2006-12-01

    Full Text Available This paper investigates the significance of combining cepstral features derived from the modified group delay function and from the short-time spectral magnitude like the MFCC. The conventional group delay function fails to capture the resonant structure and the dynamic range of the speech spectrum primarily due to pitch periodicity effects. The group delay function is modified to suppress these spikes and to restore the dynamic range of the speech spectrum. Cepstral features are derived from the modified group delay function, which are called the modified group delay feature (MODGDF. The complementarity and robustness of the MODGDF when compared to the MFCC are also analyzed using spectral reconstruction techniques. Combination of several spectral magnitude-based features and the MODGDF using feature fusion and likelihood combination is described. These features are then used for three speech processing tasks, namely, syllable, speaker, and language recognition. Results indicate that combining MODGDF with MFCC at the feature level gives significant improvements for speech recognition tasks in noise. Combining the MODGDF and the spectral magnitude-based features gives a significant increase in recognition performance of 11% at best, while combining any two features derived from the spectral magnitude does not give any significant improvement.

  20. Fuzzy delay model based fault simulator for crosstalk delay fault test generation in asynchronous sequential circuits

    Indian Academy of Sciences (India)

    S Jayanthy; M C Bhuvaneswari

    2015-02-01

    In this paper, a fuzzy delay model based crosstalk delay fault simulator is proposed. As design trends move towards nanometer technologies, more number of new parameters affects the delay of the component. Fuzzy delay models are ideal for modelling the uncertainty found in the design and manufacturing steps. The fault simulator based on fuzzy delay detects unstable states, oscillations and non-confluence of settling states in asynchronous sequential circuits. The fuzzy delay model based fault simulator is used to validate the test patterns produced by Elitist Non-dominated sorting Genetic Algorithm (ENGA) based test generator, for detecting crosstalk delay faults in asynchronous sequential circuits. The multi-objective genetic algorithm, ENGA targets two objectives of maximizing fault coverage and minimizing number of transitions. Experimental results are tabulated for SIS benchmark circuits for three gate delay models, namely unit delay model, rise/fall delay model and fuzzy delay model. Experimental results indicate that test validation using fuzzy delay model is more accurate than unit delay model and rise/fall delay model.