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Sample records for avoidance learning

  1. Avoidance learning, Pavlovian conditioning, and the development of phobias.

    Science.gov (United States)

    Siddle, D A; Bond, N W

    1988-10-01

    This paper examines the role of Pavlovian conditioning in the acquisition, maintenance and elimination of human phobias. Because many conceptualizations of human fears and phobias are based on data from studies of avoidance learning in animals, we first review theories of avoidance. Our conclusion is that none of the extant theories provides an adequate account of avoidance learning, and we propose a model of avoidance that involves Pavlovian, but not instrumental learning. We then analyse critically arguments that Pavlovian conditioning plays only a small role in the aetiology of fears. Finally, the paper examines the implications of a conditioning model of avoidance for the study of human fears and phobias.

  2. Action Learning: Avoiding Conflict or Enabling Action

    Science.gov (United States)

    Corley, Aileen; Thorne, Ann

    2006-01-01

    Action learning is based on the premise that action and learning are inextricably entwined and it is this potential, to enable action, which has contributed to the growth of action learning within education and management development programmes. However has this growth in action learning lead to an evolution or a dilution of Revan's classical…

  3. Avoidance learning : a review of theoretical models and recent developments

    NARCIS (Netherlands)

    Krypotos, Angelos-Miltiadis; Effting, Marieke; Kindt, Merel; Beckers, Tom

    2015-01-01

    Avoidance is a key characteristic of adaptive and maladaptive fear. Here, we review past and contemporary theories of avoidance learning. Based on the theories, experimental findings and clinical observations reviewed, we distill key principles of how adaptive and maladaptive avoidance behavior is a

  4. Is avoiding an aversive outcome rewarding? Neural substrates of avoidance learning in the human brain.

    Directory of Open Access Journals (Sweden)

    Hackjin Kim

    2006-07-01

    Full Text Available Avoidance learning poses a challenge for reinforcement-based theories of instrumental conditioning, because once an aversive outcome is successfully avoided an individual may no longer experience extrinsic reinforcement for their behavior. One possible account for this is to propose that avoiding an aversive outcome is in itself a reward, and thus avoidance behavior is positively reinforced on each trial when the aversive outcome is successfully avoided. In the present study we aimed to test this possibility by determining whether avoidance of an aversive outcome recruits the same neural circuitry as that elicited by a reward itself. We scanned 16 human participants with functional MRI while they performed an instrumental choice task, in which on each trial they chose from one of two actions in order to either win money or else avoid losing money. Neural activity in a region previously implicated in encoding stimulus reward value, the medial orbitofrontal cortex, was found to increase, not only following receipt of reward, but also following successful avoidance of an aversive outcome. This neural signal may itself act as an intrinsic reward, thereby serving to reinforce actions during instrumental avoidance.

  5. Asymmetric learning to avoid heterospecific males in Mesocricetus hamsters

    OpenAIRE

    delBarco-Trillo, Javier; Johnston, Robert E.

    2012-01-01

    If a female mates with a male of a closely related species, her fitness is likely to decline. Consequently, females may develop behavioral mechanisms to avoid mating with heterospecific males. In some species, one such mechanism is for adult females to learn to discriminate against heterospecific males after exposure to such males. We have previously shown that adult, female Syrian hamsters (Mesocricetus auratus) learn to discriminate against male Turkish hamsters (Mesocricetus brandti) after...

  6. Food Avoidance Learning in Squirrel Monkeys and Common Marmosets

    OpenAIRE

    Laska, Matthias; Metzker, Karin

    1998-01-01

    Using a conditioned food avoidance learning paradigm, six squirrel monkeys (Saimiri sciureus) and six common marmosets (Callithrix jacchus) were tested for their ability to (1) reliably form associations between visual or olfactory cues of a potential food and its palatability and (2) remember such associations over prolonged periods of time. We found (1) that at the group level both species showed one-trial learning with the visual cues color and shape, whereas only the marmosets were able t...

  7. Odour avoidance learning in the larva of Drosophila melanogaster

    Indian Academy of Sciences (India)

    Sukant Khurana; Mohammed Bin AbuBaker; Obaid Siddiqi

    2009-10-01

    Drosophila larvae can be trained to avoid odours associated with electric shock. We describe here, an improved method of aversive conditioning and a procedure for decomposing learning retention curve that enables us to do a quantitative analysis of memory phases, short term (STM), middle term (MTM) and long term (LTM) as a function of training cycles. The same method of analysis when applied to learning mutants dunce, amnesiac, rutabaga and radish reveals memory deficits characteristic of the mutant strains.

  8. Learning obstacle avoidance with an operant behavior model.

    Science.gov (United States)

    Gutnisky, D A; Zanutto, B S

    2004-01-01

    Artificial intelligence researchers have been attracted by the idea of having robots learn how to accomplish a task, rather than being told explicitly. Reinforcement learning has been proposed as an appealing framework to be used in controlling mobile agents. Robot learning research, as well as research in biological systems, face many similar problems in order to display high flexibility in performing a variety of tasks. In this work, the controlling of a vehicle in an avoidance task by a previously developed operant learning model (a form of animal learning) is studied. An environment in which a mobile robot with proximity sensors has to minimize the punishment for colliding against obstacles is simulated. The results were compared with the Q-Learning algorithm, and the proposed model had better performance. In this way a new artificial intelligence agent inspired by neurobiology, psychology, and ethology research is proposed.

  9. Escape and avoidance learning in the earthworm Eisenia hortensis

    Directory of Open Access Journals (Sweden)

    W. Jeffrey Wilson

    2014-01-01

    Full Text Available Interest in instrumental learning in earthworms dates back to 1912 when Yerkes concluded that they can learn a spatial discrimination in a T-maze. Rosenkoetter and Boice determined in the 1970s that the “learning” that Yerkes observed was probably chemotaxis and not learning at all. We examined a different form of instrumental learning: the ability to learn both to escape and to avoid an aversive stimulus. Freely moving “master” worms could turn off an aversive white light by increasing their movement; the behavior of yoked controls had no effect on the light. We demonstrate that in as few as 12 trials the behavior of the master worms comes under the control of this contingency.

  10. Ontogenetic development of avoidance learning in rats after eye opening.

    Science.gov (United States)

    Köllner, O; Köllner, U; Göb, R; Klingberg, F

    1988-01-01

    Five male and one female group of 8 pups were selected from 8 liters on the second postnatal day and returned to 6 dams. The animals were investigated in two subsequent tests; first, in a peripheral field avoidance test using a 60 x 75 x 22 cm open field subdivided into 20 equal squares of 15 x 15 cm with separate floor grids for electrical punishment and, second, in a W-like maze with a start arm falling into a common alley from which left and right each two goal arms branched off. Four qualities were measured in the first test: finding out that only central fields remained unpunished; the stay duration in central fields indicating passive avoidance; the response to a conditioned stimulus, when they entered peripheral fields indicating active avoidance; the quality of extinction. The differences of these qualities changed significantly from week to week as the acquisition speed and the consolidation increased, the extinction was rapid in the third week, very slow in the fourth week and adult-like in the fifth week. The self-chosen strategy of pups showed dominance of escape with subsequent motor inhibition in the third week, dominance of trials and active avoidance in the fourth week, dominance of passive avoidance in the fifth week. We found no difference between males and females, or between blind and control rats. The W-maze test revealed additionally that reversal learning from left goal to right goal was still difficult in the fourth week and that brightness-cued alteration of goals in which wrong choices were punished when a time limit was overcome could not be learned before the sixth week and not consolidated before the end of the seventh week. The results suggest that various brain processes are involved in the development of avoidance and learning strategies which mature unevenly and reach their peaks at different ages. PMID:3254159

  11. Socially dependent avoidance learning : mechanisms of adaptive behavior

    OpenAIRE

    Lindström, Björn

    2014-01-01

    Many aspects of human social behavior are likely to be shaped by punishment, threats of punishment, and avoidance of punishment. However, surprisingly little is known about the psychological mechanisms underpinning these influences. The goal of the research presented in this thesis was to investigate how basic reinforcement-based learning processes contribute to adaptive social behavior. To this end, we investigated how human behavior is shaped by punishment and threats of punishment in simpl...

  12. Providing a food reward reduces inhibitory avoidance learning in zebrafish.

    Science.gov (United States)

    Manuel, Remy; Zethof, Jan; Flik, Gert; van den Bos, Ruud

    2015-11-01

    As shown in male rats, prior history of subjects changes behavioural and stress-responses to challenges: a two-week history of exposure to rewards at fixed intervals led to slightly, but consistently, lower physiological stress-responses and anxiety-like behaviour. Here, we tested whether similar effects are present in zebrafish (Danio rerio). After two weeks of providing Artemia (brine shrimp; Artemia salina) as food reward or flake food (Tetramin) as control at fixed intervals, zebrafish were exposed to a fear-avoidance learning task using an inhibitory avoidance protocol. Half the number of fish received a 3V shock on day 1 and were tested and sacrificed on day 2; the other half received a second 3V shock on day 2 and were tested and sacrificed on day 3. The latter was done to assess whether effects are robust, as effects in rats have been shown to be modest. Zebrafish that were given Artemia showed less inhibitory avoidance after one shock, but not after two shocks, than zebrafish that were given flake-food. Reduced avoidance behaviour was associated with lower telencepahalic gene expression levels of cannabinoid receptor 1 (cnr1) and higher gene expression levels of corticotropin releasing factor (crf). These results suggest that providing rewards at fixed intervals alters fear avoidance behaviour, albeit modestly, in zebrafish. We discuss the data in the context of similar underlying brain structures in mammals and fish. PMID:26342856

  13. Reinforcement learning for congestion-avoidance in packet flow

    Science.gov (United States)

    Horiguchi, Tsuyoshi; Hayashi, Keisuke; Tretiakov, Alexei

    2005-04-01

    Occurrence of congestion of packet flow in computer networks is one of the unfavorable problems in packet communication and hence its avoidance should be investigated. We use a neural network model for packet routing control in a computer network proposed in a previous paper by Horiguchi and Ishioka (Physica A 297 (2001) 521). If we assume that the packets are not sent to nodes whose buffers are already full of packets, then we find that traffic congestion occurs when the number of packets in the computer network is larger than some critical value. In order to avoid the congestion, we introduce reinforcement learning for a control parameter in the neural network model. We find that the congestion is avoided by the reinforcement learning and at the same time we have good performance for the throughput. We investigate the packet flow on computer networks of various types of topology such as a regular network, a network with fractal structure, a small-world network, a scale-free network and so on.

  14. Trust-based learning and behaviors for convoy obstacle avoidance

    Science.gov (United States)

    Mikulski, Dariusz G.; Karlsen, Robert E.

    2015-05-01

    In many multi-agent systems, robots within the same team are regarded as being fully trustworthy for cooperative tasks. However, the assumption of trustworthiness is not always justified, which may not only increase the risk of mission failure, but also endanger the lives of friendly forces. In prior work, we addressed this issue by using RoboTrust to dynamically adjust to observed behaviors or recommendations in order to mitigate the risks of illegitimate behaviors. However, in the simulations in prior work, all members of the convoy had knowledge of the convoy goal. In this paper, only the lead vehicle has knowledge of the convoy goals and the follow vehicles must infer trustworthiness strictly from lead vehicle performance. In addition, RoboTrust could only respond to observed performance and did not dynamically learn agent behavior. In this paper, we incorporate an adaptive agent-specific bias into the RoboTrust algorithm that modifies its trust dynamics. This bias is learned incrementally from agent interactions, allowing good agents to benefit from faster trust growth and slower trust decay and bad agents to be penalized with slower trust growth and faster trust decay. We then integrate this new trust model into a trust-based controller for decentralized autonomous convoy operations. We evaluate its performance in an obstacle avoidance mission, where the convoy attempts to learn the best speed and following distances combinations for an acceptable obstacle avoidance probability.

  15. Effect of Silver nanoparticles on Passive Avoidance learning in Rats

    Directory of Open Access Journals (Sweden)

    parvin khodarahmi

    2015-09-01

    Full Text Available Background & aim: Silver nanoparticles (Ag NPs have been widely used in many technologies to produce medical devices, food technology and textiles. Silver nanoparticles may be absorbed through the lungs and intestine into circulation and thus may reach such organs as the liver, kidney, spleen, heart and testes and brain. It has been demonstrated that silver nanoparticles may have toxic effects on mammalian cells. There are some alarming reports on the adverse effects of silver nanoparticles on reproduction of experimental animals. Exposure to silver nanoparticles may exert a neurotoxic effect and affect cognitive functions, causing the impairment of short-term and working memory. The purpose of this study was to investigate the possible protective role of Ag NP on the learning and memory of rats. Methods: The present experimental study was conducted on forty male Wistar rats weighing 200 to 250 g which were divided into five groups of eight as follows: control group and 4 groups of treatment. Control group rats received saline and treatment group’s rats received Ag NP at doses of 50, 250,500 and 1000 mg/ kg/ day using Intra Peritoneal injection (IP for 14 days. One day after the last injection, the learning and memory function in the rats was examined by the passive avoidance task. Measure of memory and learning were assessed using One-Way ANOVA by SPSS using the  Tukey s' test. Results: The results showed that Ag NP at dose of 50, 250, 500 mg/kg made no significant change in the STL (step-through latency and TDC (Time in Dark Compartment, compared to the control group in the passive avoidance task. Despite, Ag NP at dose of 1000 mg/kg significantly reduced the STL (p<0.01 and increased TDC (p0.05 compared to the control group. Conclusion: These data suggest that ip microinjection of Ag NP could impair learning and memory at high doses.

  16. Rats learn to eat more to avoid hunger.

    Science.gov (United States)

    Jarvandi, Soghra; Thibault, Louise; Booth, David A

    2009-04-01

    Several recent experiments have provided evidence that the ingestion of a distinctive food by rats can be a learnt instrumental act as well as an associatively conditioned reaction. In the previous work, maintenance food was withheld for shorter and longer durations on different days following access to the training food. Extra eating before the longer fast was interpreted as avoidance of hunger. This interpretation was based on the evidence showing that extra eating as a result of classical conditioning comes from pairing food stimuli with the presence of little or no hunger because of repletion with energy nutrients. The theory that the extra eating arose from a response-depletion contingency was tested in the present experiment by training rats on only a long fast or only a short fast. Greater increase in intake was seen before the longer fast. The results also replicated previously seen cycles of increase, decrease, and renewed increase in putative deficit-avoidant eating over about three trials, indicating that the extra eating reduces the response-reinforcing hunger and that the consequent part-extinction restores reinforcement. The shape of the learning curve was consistent with these cycles occurring from the start of training, further supporting the view that the increase in food intake before a long delay in refeeding is hunger-reinforced instrumental behaviour. PMID:19048448

  17. The Relationship among Student Basic Need Satisfaction, Approaches to Learning, Reporting of Avoidance Strategies and Achievement

    Science.gov (United States)

    Betoret, Fernando Domenech; Artiga, Amparo Gomez

    2011-01-01

    Introduction: This study examines the relationship between student basic need satisfaction (autonomy, competence, relatedness and belonging), their reporting of approaches to learning (deep and surface), their reporting of avoidance strategies (avoidance of effort and challenge, avoidance of help seeking and preference to avoid novelty) and…

  18. Safe from harm: learned, instructed, and symbolic generalization pathways of human threat-avoidance.

    Directory of Open Access Journals (Sweden)

    Simon Dymond

    Full Text Available Avoidance of threatening or unpleasant events is usually an adaptive behavioural strategy. Sometimes, however, avoidance can become chronic and lead to impaired daily functioning. Excessive threat-avoidance is a central diagnostic feature of anxiety disorders, yet little is known about whether avoidance acquired in the absence of a direct history of conditioning with a fearful event differs from directly learned avoidance. In the present study, we tested whether avoidance acquired indirectly via verbal instructions and symbolic generalization result in similar levels of avoidance behaviour and threat-beliefs to avoidance acquired after direct learning. Following fear conditioning in which one conditioned stimulus was paired with shock (CS+ and another was not (CS-, participants either learned or were instructed to make a response that cancelled impending shock. Three groups were then tested with a learned CS+ and CS- (learned group, instructed CS+ (instructed group, and generalized CS+ (derived group presentations. Results showed similar levels of avoidance behaviour and threat-belief ratings about the likelihood of shock across each of the three pathways despite the different mechanisms by which they were acquired. Findings have implications for understanding the aetiology of clinical avoidance in anxiety.

  19. Effect of Royal Jelly on Improving Passive Avoidance Learning and Spatial Learning and Memory in Rats

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    H Alaei

    2012-06-01

    Full Text Available Introduction: Studies have proposed that royal jelly(RJ has various biological activities in different cells and tissues. Since it has been demonstrated that RJ contains compounds having desirable effects on central neurons system and neural functions, the present study aimed to investigate the effect of royal jelly on learning and memory in rats. Methods: Male wistar rats were divided into two groups, the royal jelly and the control. In the RJ group, the rats received a food that contained 3% RJ instead of regular food for 10 days. Then learning and memory were investigated in these animals through both passive avoidance learning test(1 day and 1 week after receiving electrical shock and Morris water maze test(1 day and 1 week after a 4-day learning period. Results: The study results indicated that the food containing RJ in the RJ group significantly increased the time of the first entrance to the dark room one week after the electrical shock in passive avoidance learning test. In other words, the findings suggest an improvement of learning and memory in RJ group. In the acquisition phase of Morris water maze test, rats receiving RJ found the underwater escape plate during less time and distance comparing with the control group. Furthermore, one week after the acquisition phase, in the retention phase, rats spent more time in the quadrant in which the escape plate was previously located. Conclusion: The present study findings propose that Royal Jelly can improve cognitive processes through positive effects on neural functions and probably has a significant influence on prevention and therapy of some neuronal disorders.

  20. Hear no evil: The effect of auditory warning signals on avian innate avoidance, learned avoidance and memory

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    Emma C. SIDDALL, Nicola M. MARPLES

    2011-04-01

    Full Text Available Many aposematic insect species advertise their toxicity to potential predators using olfactory and auditory signals, in addition to visual signals, to produce a multimodal warning display. The olfactory signals in these displays may have interesting effects, such as eliciting innate avoidance against novel colored prey, or improving learning and memory of defended prey. However, little is known about the effects of such ancillary signals when they are auditory rather than olfactory. The few studies that have investigated this question have provided conflicting results. The current study sought to clarify and extend understanding of the effects of prey auditory signals on avian predator responses. The domestic chick Gallus gallus domesticus was used as a model avian predator to examine how the defensive buzzing sound of a bumblebee Bombus terrestris affected the chick’s innate avoidance behavior, and the learning and memory of prey avoidance. The results demonstrate that the buzzing sound had no effect on the predator’s responses to unpalatable aposematically colored crumbs, suggesting that the agitated buzzing of B. terrestris may provide no additional protection from avian predators [Current Zoology 57 (2: 197–207, 2011].

  1. Hear no evil:The effect of auditory warning signals on avian innate avoidance,learned avoidance and memory

    Institute of Scientific and Technical Information of China (English)

    Emma C.SIDDALL; Nicola M.MARPLES

    2011-01-01

    Many aposematic insect species advertise their toxicity to potential predators using olfactory and auditory signals,in addition to visual signals,to produce a multimodal warning display.The olfactory signals in these displays may have interesting effects,such as eliciting innate avoidance against novel colored prey,or improving learning and memory of defended prey.However,little is known about the effects of such ancillary signals when they are auditory rather than olfactory.The few studies that have investigated this question have provided confficting results.The current study sought to clarify and extend understanding of the effects of prey auditory signals on avian predator responses.The domestic chick Gallus gallus domesticus was used as a model avian predator to examine how the defensive buzzing sound of a bumblebee Bombus terrestris affected the chick's innate avoidance behavior,and the learning and memory of prey avoidance.The resuits demonstrate that the buzzing sound had no effect on the predator's responses to unpalalable aposematically colored crumbs,suggesting that the agitated buzzing of B.terrestris may provide no additional protection from avian predators.

  2. Effects of active shock avoidance learning on hippocampal neurogenesis and plasma levels of corticosterone

    NARCIS (Netherlands)

    van der Borght, Karin; Meerlo, Peter; Luiten, Paul G.M.; Eggen, Bart J.L.; van der Zee, Eddy A.

    2005-01-01

    Hippocampal granule neurons that are newly formed during adulthood might be involved in learning and memory processes. Experimental data suggest that only hippocampus-dependent learning tasks stimulate neurogenesis. To further address this issue, the effects of active shock avoidance (ASA) learning

  3. The time course of location-avoidance learning in fear of spiders.

    Science.gov (United States)

    Rinck, Mike; Koene, Marieke; Telli, Sibel; Moerman-van den Brink, Wiltine; Verhoeven, Barbara; Becker, Eni S

    2016-01-01

    Two experiments were designed to study the time course of avoidance learning in spider fearfuls (SFs) under controlled experimental conditions. To achieve this, we employed an immersive virtual environment (IVE): While walking freely through a virtual art museum to search for specific paintings, the participants were exposed to virtual spiders. Unbeknown to the participants, only two of four museum rooms contained spiders, allowing for avoidance learning. Indeed, the more SF the participants were, the faster they learned to avoid the rooms that contained spiders (Experiment. 1), and within the first six trials, high fearfuls already developed a preference for starting their search task in rooms without spiders (Experiment 2). These results illustrate the time course of avoidance learning in SFs, and they speak to the usefulness of IVEs in fundamental anxiety research. PMID:25707541

  4. Is all motivation good for learning? Dissociable influences of approach and avoidance motivation in declarative memory

    OpenAIRE

    Murty, Vishnu P.; LaBar, Kevin S.; Hamilton, Derek A.; Adcock, R. Alison

    2011-01-01

    The present study investigated the effects of approach versus avoidance motivation on declarative learning. Human participants navigated a virtual reality version of the Morris water task, a classic spatial memory paradigm, adapted to permit the experimental manipulation of motivation during learning. During this task, participants were instructed to navigate to correct platforms while avoiding incorrect platforms. To manipulate motivational states participants were either rewarded for naviga...

  5. Random neural Q-learning for obstacle avoidance of a mobile robot in unknown environments

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    Jing Yang

    2016-07-01

    Full Text Available The article presents a random neural Q-learning strategy for the obstacle avoidance problem of an autonomous mobile robot in unknown environments. In the proposed strategy, two independent modules, namely, avoidance without considering the target and goal-seeking without considering obstacles, are first trained using the proposed random neural Q-learning algorithm to obtain their best control policies. Then, the two trained modules are combined based on a switching function to realize the obstacle avoidance in unknown environments. For the proposed random neural Q-learning algorithm, a single-hidden layer feedforward network is used to approximate the Q-function to estimate the Q-value. The parameters of the single-hidden layer feedforward network are modified using the recently proposed neural algorithm named the online sequential version of extreme learning machine, where the parameters of the hidden nodes are assigned randomly and the sample data can come one by one. However, different from the original online sequential version of extreme learning machine algorithm, the initial output weights are estimated subjected to quadratic inequality constraint to improve the convergence speed. Finally, the simulation results demonstrate that the proposed random neural Q-learning strategy can successfully solve the obstacle avoidance problem. Also, the higher learning efficiency and better generalization ability are achieved by the proposed random neural Q-learning algorithm compared with the Q-learning based on the back-propagation method.

  6. Is All Motivation Good for Learning? Dissociable Influences of Approach and Avoidance Motivation in Declarative Memory

    Science.gov (United States)

    Murty, Vishnu P.; LaBar, Kevin S.; Hamilton, Derek A.; Adcock, R. Alison

    2011-01-01

    The present study investigated the effects of approach versus avoidance motivation on declarative learning. Human participants navigated a virtual reality version of the Morris water task, a classic spatial memory paradigm, adapted to permit the experimental manipulation of motivation during learning. During this task, participants were instructed…

  7. Individual differences in sensitivity to reward and punishment and neural activity during reward and avoidance learning.

    Science.gov (United States)

    Kim, Sang Hee; Yoon, HeungSik; Kim, Hackjin; Hamann, Stephan

    2015-09-01

    In this functional neuroimaging study, we investigated neural activations during the process of learning to gain monetary rewards and to avoid monetary loss, and how these activations are modulated by individual differences in reward and punishment sensitivity. Healthy young volunteers performed a reinforcement learning task where they chose one of two fractal stimuli associated with monetary gain (reward trials) or avoidance of monetary loss (avoidance trials). Trait sensitivity to reward and punishment was assessed using the behavioral inhibition/activation scales (BIS/BAS). Functional neuroimaging results showed activation of the striatum during the anticipation and reception periods of reward trials. During avoidance trials, activation of the dorsal striatum and prefrontal regions was found. As expected, individual differences in reward sensitivity were positively associated with activation in the left and right ventral striatum during reward reception. Individual differences in sensitivity to punishment were negatively associated with activation in the left dorsal striatum during avoidance anticipation and also with activation in the right lateral orbitofrontal cortex during receiving monetary loss. These results suggest that learning to attain reward and learning to avoid loss are dependent on separable sets of neural regions whose activity is modulated by trait sensitivity to reward or punishment.

  8. Genetic determinants of individual differences in avoidance learning: behavioral and endocrine characteristics.

    Science.gov (United States)

    Brush, F R

    1991-10-15

    Bidirectional genetic selection for good and poor active avoidance learning in a shuttle box has been carried out in three independent laboratories using remarkably similar discrete-trial training procedures. The resulting strains are known as the Roman High and Low Avoidance (RHA and RLA), the Syracuse High and Low Avoidance (SHA and SLA) and the Australian High and Low Avoidance (AHA and ALA) strains, respectively. An additional unidirectionally selected strain, known as the Tokai High Avoider (THA) strain was developed in Japan using a free-operant Sidman avoidance procedure in a Skinner box. This paper reviews the selection of the Syracuse strains, enumerates the various behavioral and endocrine characteristics of the strains, and compares them to the other similarly selected strains. The behavioral work suggests that genetic selection from diverse breeding stocks has resulted in common characteristics that differentiate the strains in the emotional, not learning, domain. The endocrine data, however, are somewhat at odds. The Syracuse strains differentiate one way with respect to endocrine function, and the Roman strains differentiate in the opposite way. We suggest, therefore, that the endocrine correlates are not tightly linked to the avoidance genotype. Genetic analysis of all of the selected strains for both the avoidance phenotype and the endocrine correlates will be needed to test this hypothesis.

  9. The effect of pyrazine odor on avoidance learning and memory in wild robins Erithacus rubecula

    Institute of Scientific and Technical Information of China (English)

    Emma C.SIDDALL; Nicola M.MARPLES

    2011-01-01

    Toxic insects advertise their defended state to potential predators using warning displays.Frequently these displays use cues through more than one sensory modality,and combine color,smell and sound to produce a multimodal warning display.Signailing through more than one sensory pathway may enhance the rate of avoidance learning,and the memorability of the learned avoidance.A common insect warning odor,pyrazine,has previously been shown to increase the rate of leamed avoidance of unpalatable yellow prey by domestic chicks(Gallus gallus domesticus),and the odor also improved memory of this learned avoidance.However,to date no research has examined this response to pyraZine odor using wild birds under natural conditions.This study used wild robins(Erithacus rubecula)to investigate whether wild birds avoided yellow baits that smelled of pyrazine more strongly than those presented with no odor.The results provide some evidence that pyrazine odor does increase the level of protection an aposematic insect gains from a wild avian predator,but that the effect of pyrazine on learned avoiddance was much weaker than was found with domestic chicks.

  10. Social transmission of avoidance behavior under situational change in learned and unlearned rats.

    Directory of Open Access Journals (Sweden)

    Akira Masuda

    Full Text Available BACKGROUND: Rats receive information from other conspecifics by observation or other types of social interaction. Such social interaction may contribute to the effective adaptation to changes of environment such as situational switching. Learning to avoid dangerous places or objects rapidly occurs with even a single conditioning session, and the conditioned memory tends to be sustained over long periods. The avoidance is important for adaptation, but the details of the conditions under which the social transmission of avoidance is formed are unknown. We demonstrate that the previous experience of avoidance learning is important for the formation of behaviors for social transmission of avoidance and that the experienced rats adapt to a change of situation determined by the presence or absence of aversive stimuli. We systematically investigated social influence on avoidance behavior using a passive avoidance test in a light/dark two-compartment apparatus. METHODOLOGY/PRINCIPAL FINDINGS: Rats were divided into two groups, one receiving foot shocks and another with no aversive experience in a dark compartment. Experienced and inexperienced rats were further divided into subjects and partners. In Experiment 1, each subject experienced (1 interaction with an experienced partner, (2 interaction with an inexperienced partner, or (3 no interaction. In Experiment 2, each subject experienced interaction with a partner that received a shock. The entering latency to a light compartment was measured. The avoidance behavior of experienced rats was inhibited by interaction with inexperienced or experienced partners in a safely-changed situation. The avoidance of experienced rats was reinstated in a dangerously-changed situation by interaction with shocked rats. In contrast, the inexperienced rats were not affected by any social circumstances. CONCLUSIONS/SIGNIFICANCE: These results suggest that transmitted information among rats can be updated under a

  11. Effects of Exercise on Memory Consolidation and Retrieval of Passive Avoidance Learning In Young Male Rats

    Directory of Open Access Journals (Sweden)

    Saadati

    2010-09-01

    Full Text Available Purpose Previous studies have shown that physical activity improves learning and memory. Present study was performed to determine the effects of short term and long term treadmill exercise on learning, memory consolidation and retrieval of passive avoidance learning in an animal model. Methods In this study fifty male Wistar rats with 3-4 months of age were randomly divided into five groups (n=10 in each group. Control group was trained in passive avoidance box and was tested 10 min, 24 hr, 10 days and 3 months later. Two groups exercised on treadmill one hour at 17 m. min for 10 days and 3 months respectively and then were trained in passive avoidance box and were tested 10 min and 24 hr later. The other two groups were trained and were tested 10 days and 24 hr later and then exercised on treadmill as same as other exercised groups. Results Obtained results showed that short-term (10 days and long-term (3 months treadmill running before training by passive avoidance test had significant (P=0.006 and P=0.001 respectively effects on memory consolidation. However, no significant difference was observed between latency time of rats before and after exercise in exercised groups retrieval (P>0.05. Conclusion Our results showed that physical activity promoted learning and memory consolidation but it did not affect retrieval memory performance.

  12. The time course of location-avoidance learning in fear of spiders

    NARCIS (Netherlands)

    Rinck, M.; Koene, M.; Telli, S.; Moerman-van den Brink, W.; Verhoeven, B.; Becker, E.S.

    2016-01-01

    Two experiments were designed to study the time course of avoidance learning in spider fearfuls (SFs) under controlled experimental conditions. To achieve this, we employed an immersive virtual environment (IVE): While walking freely through a virtual art museum to search for specific paintings, the

  13. Larger error signals in major depression are associated with better avoidance learning

    Directory of Open Access Journals (Sweden)

    James F eCavanagh

    2011-11-01

    Full Text Available The medial prefrontal cortex (mPFC is particularly reactive to signals of error, punishment, and conflict in the service of behavioral adaptation and it is consistently implicated in the etiology of Major Depressive Disorder (MDD. This association makes conceptual sense, given that MDD has been associated with hyper-reactivity in neural systems associated with punishment processing. Yet in practice, depression-related variance in measures of mPFC functioning often fails to relate to performance. For example, neuroelectric reflections of mediofrontal error signals are often found to be larger in MDD, but a deficit in post-error performance suggests that these error signals are not being used to rapidly adapt behavior. Thus, it remains unknown if depression-related variance in error signals reflects a meaningful alteration in the use of error or punishment information. However, larger mediofrontal error signals have also been related to another behavioral tendency: increased accuracy in avoidance learning. The integrity of this error-avoidance system remains untested in MDD. In this study, EEG was recorded as 21 symptomatic, drug-free participants with current or past MDD and 24 control participants performed a probabilistic reinforcement learning task. Depressed participants had larger mPFC EEG responses to error feedback than controls. The direct relationship between error signal amplitudes and avoidance learning accuracy was replicated. Crucially, this relationship was stronger in depressed participants for high conflict lose-lose situations, demonstrating a selective alteration of avoidance learning. This investigation provided evidence that larger error signal amplitudes in depression are associated with increased avoidance learning, identifying a candidate mechanistic model for hypersensitivity to negative outcomes in depression.

  14. The Effect of Salmon Fish’s Oil on Avoidance Learning in Mature Male Rats

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    Seyed Ebrahim Hosseini

    2013-09-01

    Full Text Available  Background & Objective: There is plenty of fatty acids of omega-3 in Salmon Fish that affect brain development and function, therefore, this study aimed to investigate the effect of Salmon fish’s oil on learning avoidance in mature male rats.   Materials & Methods: In this empirical study, we used 40 mature male rats that were enrolled into control, sham and experimental groups. The control group was not treated. The sham group received only 1 ml saline daily, 3 experimental groups of different types received 0.25, 0.5 and 0.75 ml/kg body weight respectively, for 28 days. For the evaluation of avoidance learning behavior, the shuttle box was used. The data was evaluated using ANOVA.    Results: The results suggest that consumption of salmon oil significantly increases in minimum and maximum doses (P<0.01 and average doses (P<0.001 the process of avoidance learning.   Conclusion: Salmon oil can lead to increased learning. Therefore, further investigation can be used to treat learning disorders and memory . 

  15. Avfail in color avoidance learning by starlings (Sturnus vulgaris) and red-winged blackbirds (Agelaius phoeniceus).

    Science.gov (United States)

    Mason, J R; Arzt, A H; Reidinger, R F

    1985-12-01

    Certain unconditioned stimuli (UCS) in flavor avoidance learning sometimes become ineffective after pairings with relatively stronger UCS. This failure of avoidance learning (avfail) has been demonstrated only with rodents. The present investigations were conducted to determine whether avfail might also occur with avian species, the food selection of which is guided primarily by visual cues. In Experiment 1, starlings were given pairings of methiocarb (a relatively weak UCS) and LiCl (a relatively strong UCS). In Experiment 2, red-winged blackbirds were given pairings of two concentrations of methiocarb (relatively weak and relatively strong UCS, respectively). Pairings were followed by a conditioning trial (UCS gavage in the presence of a color cue) and two-choice tests. Conditioned avoidance was always observed except when methiocarb preceded LiCl and when the low preceded the high methiocarb dose in preconditioning pairings. Experiment 3 demonstrated that UCS habituation could not account for the results of Experiments 1 and 2. The data reflect avfail in the visual modality, and a biological implication of the results is that birds may not learn strong avoidance of aposematic prey containing varied levels of toxicant. PMID:3000688

  16. Dopamine and octopamine influence avoidance learning of honey bees in a place preference assay.

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    Maitreyi Agarwal

    Full Text Available Biogenic amines are widely characterized in pathways evaluating reward and punishment, resulting in appropriate aversive or appetitive responses of vertebrates and invertebrates. We utilized the honey bee model and a newly developed spatial avoidance conditioning assay to probe effects of biogenic amines octopamine (OA and dopamine (DA on avoidance learning. In this new protocol non-harnessed bees associate a spatial color cue with mild electric shock punishment. After a number of experiences with color and shock the bees no longer enter the compartment associated with punishment. Intrinsic aspects of avoidance conditioning are associated with natural behavior of bees such as punishment (lack of food, explosive pollination mechanisms, danger of predation, heat, etc. and their association to floral traits or other spatial cues during foraging. The results show that DA reduces the punishment received whereas octopamine OA increases the punishment received. These effects are dose-dependent and specific to the acquisition phase of training. The effects during acquisition are specific as shown in experiments using the antagonists Pimozide and Mianserin for DA and OA receptors, respectively. This study demonstrates the integrative role of biogenic amines in aversive learning in the honey bee as modeled in a novel non-appetitive avoidance learning assay.

  17. Dopamine and octopamine influence avoidance learning of honey bees in a place preference assay.

    Science.gov (United States)

    Agarwal, Maitreyi; Giannoni Guzmán, Manuel; Morales-Matos, Carla; Del Valle Díaz, Rafael Alejandro; Abramson, Charles I; Giray, Tugrul

    2011-01-01

    Biogenic amines are widely characterized in pathways evaluating reward and punishment, resulting in appropriate aversive or appetitive responses of vertebrates and invertebrates. We utilized the honey bee model and a newly developed spatial avoidance conditioning assay to probe effects of biogenic amines octopamine (OA) and dopamine (DA) on avoidance learning. In this new protocol non-harnessed bees associate a spatial color cue with mild electric shock punishment. After a number of experiences with color and shock the bees no longer enter the compartment associated with punishment. Intrinsic aspects of avoidance conditioning are associated with natural behavior of bees such as punishment (lack of food, explosive pollination mechanisms, danger of predation, heat, etc.) and their association to floral traits or other spatial cues during foraging. The results show that DA reduces the punishment received whereas octopamine OA increases the punishment received. These effects are dose-dependent and specific to the acquisition phase of training. The effects during acquisition are specific as shown in experiments using the antagonists Pimozide and Mianserin for DA and OA receptors, respectively. This study demonstrates the integrative role of biogenic amines in aversive learning in the honey bee as modeled in a novel non-appetitive avoidance learning assay.

  18. Place avoidance learning and stress-induced analgesia in the attacked mouse: role of endogenous opioids.

    Science.gov (United States)

    Siegfried, B; Frischknecht, H R

    1989-07-01

    In this study, mechanisms of pain inhibition (tail-flick test) and memory (place avoidance paradigm) were investigated in attacked, DBA/2 and C57BL/6, mice. During training, exposure of test animals to 10 or 30 bites by an aggressive, isolated ICR mouse situated in the dark half of a bright/dark conditioning box induced a significantly higher social conflict analgesia in DBA than in C57 mice. Naltrexone (0.5 and 2.0 mg/kg) reduced this response in DBA mice that received 30, but not 10, bites and was ineffective in C57 mice. This points to different, opioid versus naltrexone-insensitive nonopioid, analgesic mechanisms. During place choice testing in the same box 24 h later, DBA mice that had received 30, but not 10, bites showed a significant, naltrexone-reversible, avoidance of the attack place. No place avoidance learning was observed in C57 mice. The data provided unequivocal evidence that place avoidance learning was a result of associative conditioning, in that neither pairing nor social conflict per se significantly changed the preference for the dark side seen in experimentally naive DBA mice. Antagonism of place avoidance conditioning was observed regardless of whether testing was carried out in the drugged or undrugged state, excluding possible state-dependent effects as an explanation for the naltrexone-induced impairment. Individual correlational analysis in saline-injected, attacked DBA mice revealed a negative relationship between the analgesic state immediately after training and the avoidance of attack place during testing. In summary, the results suggest strain-dependent analgesic and learning mechanisms and indicate that endogenous opioids released in attacked DBA mice support pain inhibition and modulate the memorization of attack place by their analgesic effects, as well as by mechanisms independent of pain inhibitory systems.

  19. Palatable food avoidance and acceptance learning with different stressors in female rats

    OpenAIRE

    Liang, Nu-Chu; Smith, Megan E.; Moran, Timothy H.

    2013-01-01

    Stress activates the hypothalamus- pituitary-adrenal (HPA) axis leading to the release of glucocorticoids (GC). Increased activity of the HPA axis and GC exposure has been suggested to facilitate the development of obesity and metabolic syndrome. Nonetheless, different stressors can produce distinct effects on food intake and may support different directions of food learning e.g. avoidance or acceptance. This study examined whether interoceptive (LiCl and exendin-4) and restraint stress suppo...

  20. Chronic Rumex Patientia Seed Feeding Improves Passive Avoidance Learning and Memory in Streptozotocin-Diabetic Rats

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    Tourandokht Baluchnejadmojarad

    2010-08-01

    Full Text Available A B S T R A C T Introduction: Diabetes mellitus is accompanied with disturbances in learning, memory, and cognitive skills in the human society and experimental animals. Due to anti-diabetic and antioxidant activity of Rumex patientia (RP, this research study was conducted to evaluate the efficacy of chronic Rumex patientia feeding on alleviation of learning and memory disturbance in streptozotocindiabetic rats. Methods: Male Wistar rats were divided into control, diabetic, RP-treatedcontrol and -diabetic groups. For induction of diabetes, streptozotcin (STZ was administered at a dose of 60 mg/Kg. Meanwhile, RP-treated groups received RP seed powder mixed with standard pelleted food at a weight ratio of 6% for 4 weeks. For evaluation of learning and memory, initial latency (IL and step-through latency (STL were determined at the end of study using passive avoidance test. Results: It was found out that regarding initial latency, there was no significant difference among the groups. In addition, diabetic rats developed a significant impairment in retention and recall in passive avoidance test (p<0.01, as it is evident by a lower STL. Furthermore, RP treatment of diabetic rats did produce a significant improvement in retention and recall (p<0.05. Discussion: Taken together, chronic RP feeding could improve retention and recall capability in passive avoidance test in STZ-diabetic rats

  1. Operant avoidance learning in crayfish, Orconectes rusticus: Computational ethology and the development of an automated learning paradigm.

    Science.gov (United States)

    Bhimani, Rohan; Huber, Robert

    2016-09-01

    Research in crustaceans offers a valuable perspective for studying the neural implementation of conserved behavioral phenomena, including motivation, escape, aggression, and drug-sensitive reward. The present work adds to this literature by demonstrating that crayfish successfully learn to respond to spatially contingent cues. An integrated video-tracking system automatically delivered a mild electric shock when a test animal entered or remained on a substrate paired with punishment. Following a few instances of shock delivery, crayfish quickly learned to avoid these areas. Comparable changes in substrate preference were not exhibited by yoked controls, but locomotion differed significantly from both pre-conditioning levels and from those of their masters receiving shock in a contingent fashion. The results of this work provide valuable insights into the principles governing avoidance learning in an invertebrate system and provide a behavioral template for exploring the neural changes during associative learning. Serving as a case study, this project introduces a new computer framework for the automated control of learning paradigms. Based on routines contained within the JavaGrinders library (free download at iEthology.com), it integrates real-time video tracking with robotic interfaces, and provides a suitable framework for implementing automated learning paradigms. PMID:26542703

  2. EtOH self-administration on shuttle box avoidance learning and extinction in rats.

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    Pallarés, M A; Nadal, R A; Hernández-Torres, M; Ferré, N A

    1997-01-01

    The effects of ethanol on the acquisition and extinction of the two-way active avoidance response were examined in adult, male Wistar rats from two treatment groups, oral self-administration of alcohol solution (10% v/v ethanol and 3% w/v glucose in distilled water) and oral self-administration of control solution (3% w/v glucose in distilled water). Alcohol or control solutions were available 1 h per day during 15 days simultaneously with food, with free water for the rest of the day. Blood was drawn in the last day of this phase to evaluate blood ethanol levels (BEL). After this period, rats were tested in a two-bottle paradigm for 1 h per day and placed in a shuttle box immediately afterwards. This phase went lasted for 10 days. Subjects were trained to avoid an electric foot shock in the first 5 days (15 trials per day). Following this, half of the subjects were tested in an "easy extinction with punishment" (EEP) and the other half in a "difficult extinction with punishment" (DEP) of the avoidance response for the last 5 days. Alcohol accelerates the avoidance responding acquisition, and no significant effects of alcohol were seen in the extinction phase. Data are discussed in terms of the specificity of the effects of alcohol on learning. PMID:9305467

  3. Telencephalic neural activation following passive avoidance learning in a terrestrial toad.

    Science.gov (United States)

    Puddington, Martín M; Daneri, M Florencia; Papini, Mauricio R; Muzio, Rubén N

    2016-12-15

    The present study explores passive avoidance learning and its neural basis in toads (Rhinella arenarum). In Experiment 1, two groups of toads learned to move from a lighted compartment into a dark compartment. After responding, animals in the experimental condition were exposed to an 800-mM strongly hypertonic NaCl solution that leads to weight loss. Control animals received exposure to a 300-mM slightly hypertonic NaCl solution that leads to neither weight gain nor loss. After 10 daily acquisition trials, animals in the experimental group showed significantly longer latency to enter the dark compartment. Additionally, 10 daily trials in which both groups received the 300-mM NaCl solution after responding eliminated this group effect. Thus, experimental animals showed gradual acquisition and extinction of a passive avoidance respond. Experiment 2 replicated the gradual acquisition effect, but, after the last trial, animals were sacrificed and neural activation was assessed in five brain regions using AgNOR staining for nucleoli-an index of brain activity. Higher activation in the experimental animals, relative to controls, was observed in the amygdala and striatum. Group differences in two other regions, lateral pallium and septum, were borderline, but nonsignificant, whereas group differences in the medial pallium were nonsignificant. These preliminary results suggest that a striatal-amygdala activation could be a key component of the brain circuit controlling passive avoidance learning in amphibians. The results are discussed in relation to the results of analogous experiments with other vertebrates. PMID:27498147

  4. Learned parasite avoidance is driven by host personality and resistance to infection in a fish-trematode interaction.

    Science.gov (United States)

    Klemme, Ines; Karvonen, Anssi

    2016-09-14

    Cognitive abilities related to the assessment of risk improve survival. While earlier studies have examined the ability of animals to learn to avoid predators, learned parasite avoidance has received little interest. In a series of behavioural trials with the trematode parasite Diplostomum pseudospathaceum, we asked whether sea trout (Salmo trutta trutta) hosts show associative learning in the context of parasitism and if so, whether learning capacity is related to the likelihood of infection mediated through host personality and resistance. We show that animals are capable of learning to avoid visual cues associated with the presence of parasites. However, avoidance behaviour ceased after the likely activation of host resistance following consecutive exposures during learning, suggesting that resistance to infection outweighs avoidance. Further, we found a positive relationship between learning ability and boldness, suggesting a compensation of risky lifestyles through increased investment in cognitive abilities. By contrast, an increased risk of infection due to low resistance was not balanced by learning ability. Instead, these traits were positively related, which may be explained by inherent physiological qualities controlling both traits. Overall, the results demonstrate that parasitism, in addition to other biological interactions such as predation, is an important selective factor in the evolution of animal cognition. PMID:27605504

  5. Requirement of Dopamine Signaling in the Amygdala and Striatum for Learning and Maintenance of a Conditioned Avoidance Response

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    Darvas, Martin; Fadok, Jonathan P.; Palmiter, Richard D.

    2011-01-01

    Two-way active avoidance (2WAA) involves learning Pavlovian (association of a sound cue with a foot shock) and instrumental (shock avoidance) contingencies. To identify regions where dopamine (DA) is involved in mediating 2WAA, we restored DA signaling in specific brain areas of dopamine-deficient (DD) mice by local reactivation of conditionally…

  6. Hispanics' SAT Scores: The Influences of Level of Parental Education, Performance-Avoidance Goals, and Knowledge about Learning

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    Hannon, Brenda

    2015-01-01

    This study uncovers which learning (epistemic belief of learning), socioeconomic background (level of parental education, family income) or social-personality factors (performance-avoidance goals, test anxiety) mitigate the ethnic gap in SAT (Scholastic Assessment Test) scores. Measures assessing achievement motivation, test anxiety, socioeconomic…

  7. Post-attack aposematic display in prey facilitates predator avoidance learning

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    Changku eKang

    2016-04-01

    Full Text Available Warning signals protect unpalatable prey from predation because predators who learn the association between the warning signal and prey unprofitability decrease attacks on the prey. Most of the research have focused on visual aposematic signals that are constantly presented and visible to the predators. But a variety of chemically defended insects are rather cryptic when resting, and only in response to predator attacks (post-attack they perform displays of conspicuous abdomens or hindwings normally hidden under forewings. The function of those displays in unpalatable insects is not well understood. We examined two adaptive hypotheses on this facultative aposematic display using wild-caught oriental tits (Parus minor as predators. First, we tested whether the display increases the rejection of the prey by predators upon seeing the display (i.e. at the moment of attack through learning trials (aposematic signaling hypothesis. Second, we tested whether the display facilitates the memory formation between cryptic visible form of the prey and prey defense so that it prevents the predators initiate an attack upon seeing the cryptic form (facilitation hypothesis. We found that predators learned to avoid attacking the prey which supports the facilitation hypothesis. However, the support for the aposematic signaling hypothesis was equivocal. Our results open new directions of research by highlighting the possibility that similar facilitation effects may contribute to the evolution of various forms of post-attack visual displays in chemically, or otherwise, defended animals.

  8. Spontaneous and artificial lesions of magnocellular reticular formation of brainstem deteriorate avoidance learning in senescence-accelerated mouse SAM.

    Science.gov (United States)

    Yagi, H; Akiguchi, I; Ohta, A; Yagi, N; Hosokawa, M; Takeda, T

    1998-04-27

    The role of the magnocellular reticular formation (MGRF) of the brainstem on learning and memory was examined in memory-deficient mice with spontaneous spongy degeneration in the brainstem (senescence-accelerated mouse, SAMP8) and control mice (accelerated-senescence resistant mouse, SAMR 1). SAMP8 showed spontaneous age-related impairment of learning and memory, as determined by passive and active avoidance responses. The deficits of learning and memory function in passive avoidance performances began at two months of age and increased with ageing. In the brains of SAMP8 at one month of age and older, spongy degeneration was mainly observed in the brainstem, while no vacuoles were evident in SAMR1 control (normal ageing mouse) brains in the age range tested (up to 12 months). The vacuolization in SAMP8 was marked in the MGRF, especially in the dorsomedial MGRF. Quantitative analysis of the vacuolization showed that the total area and number of vacuoles in the MGRF increased with age, and they were affected by the degree of deficits in learning and memory. The latency 24 h after footshock in passive avoidance tests decreased with the increase in total area and number of vacuoles in MGRF. The number of shocks in active avoidance tests increased with the increase in total number and area of vacuoles. Thus, learning and memory ability in passive and active avoidance responses deteriorated with enlargement in the vacuolated area in MGRF, and it was assumed that MGRF (especially, the dorsomedial part) possesses functions related to learning and memory. To confirm this notion, behavior and memory tests (passive avoidance and active avoidance tests, open field tests and shock sensitivity measurements) were carried out in SAMR1 mice, whose bilateral dorsomedial MGRF was destroyed electrolytically (MGRF-lesioned mice). The MGRF-lesioned mice showed no difference from sham mice in sensory threshold or open field activity; however, there was severe deterioration in passive

  9. The Effect of Synchronized Running Activity with Chronic Stress on Passive Avoidance Learning and Body Weight in Rats

    OpenAIRE

    Maryam Radahmadi; Hojjatallah Alaei; Mohammad R Sharifi; Nasrin Hosseini

    2013-01-01

    Background: Different stressors induce learning and memory impairment and physical activity influence learning and memory enhancement. In this research, we investigated the effect of synchronized running activity with stress on acquisition and retention time of passive avoidance test. Methods: Male Wistar rats were randomly divided into five groups as follows: Control (Co), Sham (Sh), Exercise (Ex), Stress (St), synchronized exercise with stress (St and Ex) groups. Chronic restraint stres...

  10. Effect of Calendula officinalis hydroalcoholic extract on passive avoidance learning and memory in streptozotocin-induced diabetic rats

    OpenAIRE

    Shirin Moradkhani; Iraj Salehi; Somayeh Abdolmaleki; Alireza Komaki

    2015-01-01

    Background: Medicinal plants, owing to their different mechanisms such as antioxidants effects, may improve learning and memory impairments in diabetic rats. Calendula officinalis (CO), has a significant antioxidant activity. Aims: To examine the effect of hydroalcoholic extract of CO on passive avoidance learning (PAL) and memory in streptozotocin (STZ)-induced diabetic male rats. Settings and Design: A total of 32 adult male Wistar rats were randomly allocated to four groups: Contro...

  11. Learned helplessness and social avoidance in the Wistar-Kyoto rat

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    Hyungwoo eNam

    2014-04-01

    Full Text Available The Wistar-Kyoto (WKY rat is an established depression model characterized by elevated anxiety- and depression-like behavior across a variety of tests. Here we further characterized specific behavioral and functional domains relevant to depression that are altered in WKY rats. Moreover, since early-life experience potently shapes emotional behavior, we also determined whether aspects of WKYs’ phenotype were modifiable by early-life factors using neonatal handling or maternal separation. We first compared WKYs’ behavior to that of Sprague-Dawley (SD, Wistar, and Spontaneously Hypertensive (SHR rats in: the open field test, elevated plus maze, novelty-suppressed feeding test, a social interaction test, and the forced swim test (FST. WKYs exhibited high baseline immobility in the FST and were the only strain to show increased immobility on FST Day 2 vs. Day 1 (an indicator of learned helplessness. WKYs also showed greater social avoidance, along with enlarged adrenal glands and hearts relative to other strains. We next tested whether neonatal handling or early-life maternal separation stress influenced WKYs’ behavior. Neither manipulation affected their anxiety- and depressive-like behaviors, likely due to a strong genetic underpinning of their phenotype. Our findings indicate that WKY rats are a useful model that captures specific functional domains relevant to clinical depression including: psychomotor retardation, behavioral inhibition, learned helplessness, social withdrawal, and physiological dysfunction. WKY rats appear to be resistant to early-life manipulations (i.e. neonatal handling that are therapeutic in other strains, and may be a useful model for the development of personalized anti-depressant therapies for treatment resistant depression.

  12. Modulation of NR1 Subunit of N-Methyl-D-Aspartate Receptor by Ovariectomy and Passive Avoidance Learning

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    Mahnaz Taherianfard

    2012-10-01

    Full Text Available BACKGROUND: Learning and memory are the most intensively studied subjects in neuroscience. Various approaches have been used to understand the underlying cellular and molecular mechanisms. Numerous studies have shown that different sites of brain are involved in learning and memory mechanisms. Two sites of mammalian brain that show high density of these receptors are CA1 region of hippocampus and Purkinje cell layer of cerebellum.METHODS: Twenty four Sprague-Dawley rats were used in 4 groups: Control-1 (intact without learning; control-2 (intact with learning; ovariectomy (OVX without learning and OVX with learning. A shuttle box apparatus used for passive avoidance learning procedure. Immunohistochemical procedure was used for determination of NR1 subunit of N-methyl-D-aspartate (NMDA receptor. Photoshop software was used for determination of color intensity.RESULTS: Immunohistological finding of this experiment indicated that OVX has a negative effect on density of NR1 subunit of NMDA receptors in two brain regions. Other finding of this study showed that passive avoidance learning significantly increased density of NR1 subunit of NMDA receptors in two brain regions.CONCLUSION: These results indicated that the sex hormone can modulate function and expression of the NR1 subunit of NMDA receptor in CA1 region of hippocampus and Purkinje cell layer of cerebellum.

  13. Absence of "Warm-Up" during Active Avoidance Learning in a Rat Model of Anxiety Vulnerability: Insights from Computational Modeling.

    Science.gov (United States)

    Myers, Catherine E; Smith, Ian M; Servatius, Richard J; Beck, Kevin D

    2014-01-01

    Avoidance behaviors, in which a learned response causes omission of an upcoming punisher, are a core feature of many psychiatric disorders. While reinforcement learning (RL) models have been widely used to study the development of appetitive behaviors, less attention has been paid to avoidance. Here, we present a RL model of lever-press avoidance learning in Sprague-Dawley (SD) rats and in the inbred Wistar Kyoto (WKY) rat, which has been proposed as a model of anxiety vulnerability. We focus on "warm-up," transiently decreased avoidance responding at the start of a testing session, which is shown by SD but not WKY rats. We first show that a RL model can correctly simulate key aspects of acquisition, extinction, and warm-up in SD rats; we then show that WKY behavior can be simulated by altering three model parameters, which respectively govern the tendency to explore new behaviors vs. exploit previously reinforced ones, the tendency to repeat previous behaviors regardless of reinforcement, and the learning rate for predicting future outcomes. This suggests that several, dissociable mechanisms may contribute independently to strain differences in behavior. The model predicts that, if the "standard" inter-session interval is shortened from 48 to 24 h, SD rats (but not WKY) will continue to show warm-up; we confirm this prediction in an empirical study with SD and WKY rats. The model further predicts that SD rats will continue to show warm-up with inter-session intervals as short as a few minutes, while WKY rats will not show warm-up, even with inter-session intervals as long as a month. Together, the modeling and empirical data indicate that strain differences in warm-up are qualitative rather than just the result of differential sensitivity to task variables. Understanding the mechanisms that govern expression of warm-up behavior in avoidance may lead to better understanding of pathological avoidance, and potential pathways to modify these processes. PMID:25183956

  14. Absence of warm-up during active avoidance learning in a rat model of anxiety vulnerability: Insights from computational modeling

    Directory of Open Access Journals (Sweden)

    Catherine E Myers

    2014-08-01

    Full Text Available Avoidance behaviors, in which a learned response causes omission of an upcoming punisher, are a core feature of many psychiatric disorders. While reinforcement learning (RL models have been widely used to study the development of appetitive behaviors, less attention has been paid to avoidance. Here, we present a RL model of leverpress avoidance learning in Sprague-Dawley (SD rats, and in the inbred Wistar-Kyoto (WKY rat, which has been proposed as a model of anxiety vulnerability. We focus on warm-up, transiently decreased avoidance responding at the start of a testing session, which is shown by SD but not WKY rats. We first show that a RL model can correctly simulate key aspects of acquisition, extinction, and warm-up in SD rats; we then show that WKY behavior can be simulated by altering three model parameters, which respectively govern the tendency to explore new behaviors vs. exploit previously-reinforced ones, the tendency to repeat previous behaviors regardless of reinforcement, and the learning rate for predicting future outcomes. This suggests that several, dissociable mechanisms may contribute independently to strain differences in behavior. The model predicts that, if the standard inter-session interval is shortened from 48 to 24 hours, SD rats (but not WKY will continue to show warm-up; we confirm this prediction in an empirical study with SD and WKY rats. The model further predicts that SD rats will continue to show warm-up with inter-session intervals as short as a few minutes, while WKY rats will not show warm-up, even with inter-session intervals as long as a month. Together, the modeling and empirical data indicate that strain differences in warm-up are qualitative, rather than just the result of differential sensitivity to task variables. Understanding the mechanisms that govern expression of warm-up behavior in avoidance may lead to better understanding of pathological avoidance, and potential pathways to modify these processes.

  15. α1-Adrenoceptors in the hippocampal dentate gyrus involved in learning-dependent long-term potentiation during active-avoidance learning in rats.

    Science.gov (United States)

    Lv, Jing; Zhan, Su-Yang; Li, Guang-Xie; Wang, Dan; Li, Ying-Shun; Jin, Qing-Hua

    2016-11-01

    The hippocampus is the key structure for learning and memory in mammals and long-term potentiation (LTP) is an important cellular mechanism responsible for learning and memory. The influences of norepinephrine (NE) on the modulation of learning and memory, as well as LTP, through β-adrenoceptors are well documented, whereas the role of α1-adrenoceptors in learning-dependent LTP is not yet clear. In the present study, we measured extracellular concentrations of NE in the hippocampal dentate gyrus (DG) region using an in-vivo brain microdialysis and high-performance liquid chromatography techniques during the acquisition and extinction of active-avoidance behavior in freely moving conscious rats. Next, the effects of prazosin (an antagonist of α1-adrenoceptor) and phenylephrine (an agonist of the α1-adrenoceptor) on amplitudes of field excitatory postsynaptic potential were measured in the DG region during the active-avoidance behavior. Our results showed that the extracellular concentration of NE in the DG was significantly increased during the acquisition of active-avoidance behavior and gradually returned to the baseline level following extinction training. A local microinjection of prazosin into the DG significantly accelerated the acquisition of the active-avoidance behavior, whereas a local microinjection of phenylephrine retarded the acquisition of the active-avoidance behavior. Furthermore, in all groups, the changes in field excitatory postsynaptic potential amplitude were accompanied by corresponding changes in active-avoidance behavior. Our results suggest that NE activation of α1-adrenoceptors in the hippocampal DG inhibits active-avoidance learning by modulation of synaptic efficiency in rats.

  16. Changes in brain oxidative metabolism induced by inhibitory avoidance learning and acute administration of amitriptyline.

    Science.gov (United States)

    González-Pardo, Héctor; Conejo, Nélida M; Arias, Jorge L; Monleón, Santiago; Vinader-Caerols, Concepción; Parra, Andrés

    2008-05-01

    The effects of antidepressant drugs on memory have been somewhat ignored, having been considered a mere side effect of these compounds. However, the memory impairment caused by several antidepressants could be considered to form part of their therapeutic effects. Amitriptyline is currently one of the most prescribed tricyclic antidepressants, and exerts marked anticholinergic and antihistaminergic effects. In this study, we evaluated the effects of inhibitory avoidance (IA) learning and acute administration of amitriptyline on brain oxidative metabolism. Brain oxidative metabolism was measured in several limbic regions using cytochrome oxidase (CO) quantitative histochemistry. Amitriptyline produced a clear impairment in the IA task. In animals exposed only to the apparatus, amitriptyline decreased CO activity in nine brain regions, without affecting the remaining regions. In animals that underwent the IA training phase, amitriptyline reduced CO activity in only three of these nine regions. In animals treated with saline, IA acquisition increased CO activity in the medial prefrontal cortex, the prelimbic cortex, and the medial mammillary body, and diminished it in the medial septum and the nucleus basalis of Meynert with respect to animals exposed only to the IA apparatus. In animals treated with amitriptyline, IA acquisition did not modify CO activity in any of these regions, but increased it in the anteromedial nucleus of the thalamus, the diagonal band of Broca, and the dentate gyrus. The results reveal a pattern of changes in brain oxidative metabolism induced by IA training in saline-treated animals that was clearly absent in animals submitted to the same behavioural training but treated with amitriptyline. PMID:18313125

  17. Age-dependent improvement in passive avoidance learning of the young chick: cholinergic mediation?

    Science.gov (United States)

    Zolman, J F; Mattingly, B A

    1982-06-01

    Cholinergic mediation of the age-dependent improvement in response suppression of the young chick was studied by determining the performance of 4-day-old chicks, pretreated with scopolamine, during passive avoidance (PA) and extinction testing. In Experiment 1, chicks were trained briefly to key peck for heat reward (prepunishment training), and then tested for PA learning under immediate, 2-sec-delayed, or no shock condition. Half of the chicks in each wing-shock (5 mA, 5 sec) condition received saline injections before prepunishment training and .5 mg/kg scopolamine injections after prepunishment training. The rest of the chicks received .5 mg/kg scopolamine injections both before and after prepunishment training. For chicks in both scopolamine groups, delaying shock onset resulted in significantly less response suppression than immediate response-contingent shock. In Experiment 2, 4-day-old chicks injected with either saline or scopolamine were trained to key peck for heat reward and then tested for resistance to extinction under either response-contingent shock or nonshock conditions. Punishment decreased the number of extinction responses for both saline and scopolamine groups of chicks. Previous studies have shown that normal 1-day-old chicks do not show a significant delay of punishment effect during PA testing and that response-contingent punishment increases the number of their responses during extinction. Hence, the results of the present experiments indicate that the age-dependent improvement in response suppression of the young chick cannot be explained solely by a significant increase in central cholinergic functioning. PMID:7096681

  18. Hemispheric Asymmetries in Striatal Reward Responses Relate to Approach-Avoidance Learning and Encoding of Positive-Negative Prediction Errors in Dopaminergic Midbrain Regions.

    Science.gov (United States)

    Aberg, Kristoffer Carl; Doell, Kimberly C; Schwartz, Sophie

    2015-10-28

    Some individuals are better at learning about rewarding situations, whereas others are inclined to avoid punishments (i.e., enhanced approach or avoidance learning, respectively). In reinforcement learning, action values are increased when outcomes are better than predicted (positive prediction errors [PEs]) and decreased for worse than predicted outcomes (negative PEs). Because actions with high and low values are approached and avoided, respectively, individual differences in the neural encoding of PEs may influence the balance between approach-avoidance learning. Recent correlational approaches also indicate that biases in approach-avoidance learning involve hemispheric asymmetries in dopamine function. However, the computational and neural mechanisms underpinning such learning biases remain unknown. Here we assessed hemispheric reward asymmetry in striatal activity in 34 human participants who performed a task involving rewards and punishments. We show that the relative difference in reward response between hemispheres relates to individual biases in approach-avoidance learning. Moreover, using a computational modeling approach, we demonstrate that better encoding of positive (vs negative) PEs in dopaminergic midbrain regions is associated with better approach (vs avoidance) learning, specifically in participants with larger reward responses in the left (vs right) ventral striatum. Thus, individual dispositions or traits may be determined by neural processes acting to constrain learning about specific aspects of the world. PMID:26511241

  19. Hemispheric Asymmetries in Striatal Reward Responses Relate to Approach-Avoidance Learning and Encoding of Positive-Negative Prediction Errors in Dopaminergic Midbrain Regions.

    Science.gov (United States)

    Aberg, Kristoffer Carl; Doell, Kimberly C; Schwartz, Sophie

    2015-10-28

    Some individuals are better at learning about rewarding situations, whereas others are inclined to avoid punishments (i.e., enhanced approach or avoidance learning, respectively). In reinforcement learning, action values are increased when outcomes are better than predicted (positive prediction errors [PEs]) and decreased for worse than predicted outcomes (negative PEs). Because actions with high and low values are approached and avoided, respectively, individual differences in the neural encoding of PEs may influence the balance between approach-avoidance learning. Recent correlational approaches also indicate that biases in approach-avoidance learning involve hemispheric asymmetries in dopamine function. However, the computational and neural mechanisms underpinning such learning biases remain unknown. Here we assessed hemispheric reward asymmetry in striatal activity in 34 human participants who performed a task involving rewards and punishments. We show that the relative difference in reward response between hemispheres relates to individual biases in approach-avoidance learning. Moreover, using a computational modeling approach, we demonstrate that better encoding of positive (vs negative) PEs in dopaminergic midbrain regions is associated with better approach (vs avoidance) learning, specifically in participants with larger reward responses in the left (vs right) ventral striatum. Thus, individual dispositions or traits may be determined by neural processes acting to constrain learning about specific aspects of the world.

  20. The role of dopamine in the context of aversive stimuli with particular reference to acoustically signaled avoidance learning

    Directory of Open Access Journals (Sweden)

    Anton eIlango

    2012-09-01

    Full Text Available Learning from punishment is a powerful means for behavioral adaptation with high relevance for various mechanisms of self-protection. Several studies have explored the contribution of released dopamine (DA or responses of DA neurons on reward seeking using rewards such as food, water, and sex. Phasic DA signals evoked by rewards or conditioned reward predictors are well documented, as are modulations of these signals by such parameters as reward magnitude, probability, and deviation of actually occurring from expected rewards. Less attention has been paid to DA neuron firing and DA release in response to aversive stimuli, and the prediction and avoidance of punishment. In this review, we first focus on DA changes in response to aversive stimuli as measured by microdialysis and voltammetry followed by the change in electrophysiological signatures by aversive stimuli and fearful events. We subsequently focus on the role of DA and effect of DA manipulations on signaled avoidance learning, which consists of learning the significance of a warning cue through Pavlovian associations and the execution of an instrumental avoidance response. We present a coherent framework utilizing the data on microdialysis, voltammetry, electrophysiological recording, electrical brain stimulation and behavioral analysis. We end by outlining current gaps in the literature and proposing future directions aimed at incorporating technical and conceptual progress to understand the involvement of reward circuit on punishment based decisions.

  1. Avoidance learning under delayed shock termination in prenatally x-irradiated rats

    International Nuclear Information System (INIS)

    Groups of MPI male albino rats were exposed to x-irradiation of 200 rad on Day 17 of gestation. Irradiated and control rats were trained in a shuttle box with either immediate or .5-sec delayed termination of both the electric shock and the conditioned stimulus on escape trials. An avoidance response always produced prompt CS termination. Irradiated rats showed a higher degree of avoidance behavior than controls and, under the delay condition, tended to run rapidly in the CS-US interval

  2. Associative learning for danger avoidance nullifies innate positive chemotaxis to host olfactory stimuli in a parasitic wasp.

    Science.gov (United States)

    Benelli, Giovanni; Stefanini, Cesare; Giunti, Giulia; Geri, Serena; Messing, Russell H; Canale, Angelo

    2014-09-01

    Animals rely on associative learning for a wide range of purposes, including danger avoidance. This has been demonstrated for several insects, including cockroaches, mosquitoes, drosophilid flies, paper wasps, stingless bees, bumblebees and honeybees, but less is known for parasitic wasps. We tested the ability of Psyttalia concolor (Hymenoptera: Braconidae) females to associate different dosages of two innately attractive host-induced plant volatiles (HIPVs), ethyl octanoate and decanal, with danger (electric shocks). We conducted an associative treatment involving odours and shocks and two non-associative controls involving shocks but not odours and odours but not shocks. In shock-only and odour-only trained wasps, females preferred on HIPV-treated than on blank discs. In associative-trained wasps, however, P. concolor's innate positive chemotaxis for HIPVs was nullified (lowest HIPV dosage tested) or reversed (highest HIPV dosage tested). This is the first report of associative learning of olfactory cues for danger avoidance in parasitic wasps, showing that the effects of learning can override innate positive chemotaxes.

  3. Associative learning for danger avoidance nullifies innate positive chemotaxis to host olfactory stimuli in a parasitic wasp

    Science.gov (United States)

    Benelli, Giovanni; Stefanini, Cesare; Giunti, Giulia; Geri, Serena; Messing, Russell H.; Canale, Angelo

    2014-09-01

    Animals rely on associative learning for a wide range of purposes, including danger avoidance. This has been demonstrated for several insects, including cockroaches, mosquitoes, drosophilid flies, paper wasps, stingless bees, bumblebees and honeybees, but less is known for parasitic wasps. We tested the ability of Psyttalia concolor (Hymenoptera: Braconidae) females to associate different dosages of two innately attractive host-induced plant volatiles (HIPVs), ethyl octanoate and decanal, with danger (electric shocks). We conducted an associative treatment involving odours and shocks and two non-associative controls involving shocks but not odours and odours but not shocks. In shock-only and odour-only trained wasps, females preferred on HIPV-treated than on blank discs. In associative-trained wasps, however, P. concolor's innate positive chemotaxis for HIPVs was nullified (lowest HIPV dosage tested) or reversed (highest HIPV dosage tested). This is the first report of associative learning of olfactory cues for danger avoidance in parasitic wasps, showing that the effects of learning can override innate positive chemotaxes.

  4. Effects of chronic treatment with commonly used antiepileptic drugs on passive avoidance learning in prepubertal rats

    OpenAIRE

    Yildirim, Mehmet; ABİDİN, Ismail; CANSU, Ali

    2013-01-01

    Antiepileptic drugs (AEDs), which are widely used to control and prevent epileptic seizures in children with epilepsy, have potential cognitive side effects. There have been several reports respecting different effects of the first and second generation ADEs on learning and memory. Therefore, we investigated the effects of valproate, carbamazepine, levetiracetam, oxcarbazepine, lamotrigine and topiramate, administered chronically by gavage for 21 days, on learning and memory retention of male...

  5. The Effect of Ginkgo on Baclofen Induced Amnesia using Passive Avoidance Learning and Memory in Rats

    OpenAIRE

    Elaheh Nooshinfar; Mostafa Rezaei Tavirani; Akram Safaei; Yara Tambrchi

    2015-01-01

    Background & Objective: Ginkgo biloba is an herbal medicine that has a positive effect on improving memory. It prevents oxidative damage in mitochondria and cell death in a variety of Neuropathies. Besides, baclofen is prescribed for its analgesic and anti-inflammatory effects but has negative impact on memory. The objective of this study is to investigate the interaction of ginkgo with GABA b receptor agonist (baclofen) by passive avoidance behavior in mice. Materials & Methods: Passive ...

  6. Brief postnatal exposure to phenobarbital impairs passive avoidance learning and sensorimotor gating in rats.

    Science.gov (United States)

    Gutherz, Samuel B; Kulick, Catherine V; Soper, Colin; Kondratyev, Alexei; Gale, Karen; Forcelli, Patrick A

    2014-08-01

    Phenobarbital is the most commonly utilized drug for the treatment of neonatal seizures. However, mounting preclinical evidence suggests that even brief exposure to phenobarbital in the neonatal period can induce neuronal apoptosis, alterations in synaptic development, and long-lasting changes in behavioral functions. In the present report, we treated neonatal rat pups with phenobarbital and evaluated behavior in adulthood. Pups were treated initially with a loading dose (80 mg/kg) on postnatal day (P)7 and with a lower dose (40 mg/kg) on P8 and P9. We examined sensorimotor gating (prepulse inhibition), passive avoidance, and conditioned place preference for cocaine when the animals reached adulthood. Consistent with our previous reports, we found that three days of neonatal exposure to phenobarbital significantly impaired prepulse inhibition compared with vehicle-exposed control animals. Using a step-though passive avoidance paradigm, we found that animals exposed to phenobarbital as neonates and tested as adults showed significant deficits in passive avoidance retention compared with matched controls, indicating impairment in associative memory and/or recall. Finally, we examined place preference conditioning in response to cocaine. Phenobarbital exposure did not alter the normal conditioned place preference associated with cocaine exposure. Our findings expand the profile of behavioral toxicity induced by phenobarbital. PMID:25112558

  7. Avoidance and contextual learning induced by a kairomone, a pheromone and a common odorant in female CD1 mice

    Directory of Open Access Journals (Sweden)

    Lluís eFortes-Marco

    2015-10-01

    Full Text Available Chemosignals mediate both intra- and inter-specific communication in most mammals. Pheromones elicit stereotyped reactions in conspecifics, whereas kairomones provoke a reaction in an allospecific animal. For instance, predator kairomones elicit anticipated defensive responses in preys. The aim of this work was to test the behavioral responses of female mice to two chemosignals: 2-heptanone (2-HP, a putative alarm pheromone, and 2,4,5-trimethylthiazoline (TMT, a fox-derived putative kairomone, widely used to investigate fear and anxiety in rodents. The banana-like odorant isoamyl acetate (IA, unlikely to act as a chemosignal, served as a control odorant. We first presented increasing amounts of these odorants in consecutive days, in a test box in which mice could explore or avoid them. Female mice avoided the highest amounts of all three compounds, with TMT and IA eliciting avoidance at lower amounts (3.8 pmol and 0.35 μmol, respectively than 2-HP (35 μmol. All three compounds induced minimal effects in global locomotion and immobility in this set up. Further, mice detected 3.5 pmol of TMT and IA in a habituation-dishabituation test, so avoidance of IA started well beyond the detection threshold. Finally, both TMT and IA, but not 2-HP, induced conditioned place avoidance and increased immobility in the neutral compartment during a contextual memory test. These data suggest that intense odors can induce contextual learning irrespective of their putative biological significance. Our results support that synthetic predator-related compounds (like TMT or other intense odorants are useful to investigate the neurobiological basis of emotional behaviors in rodents. Since intense odorants unlikely to act as chemosignals can elicit similar behavioral reactions than chemosignals, we stress the importance of using behavioral measures in combination with other physiological (e.g. hormonal levels or neural measures (e.g. immediate early gene expression to

  8. The effect of synchronized running activity with chronic stress on passive avoidance learning and body weight in rats

    Directory of Open Access Journals (Sweden)

    Maryam Radahmadi

    2013-01-01

    Results: Our results showed that: (1 Exercise under no stress provides beneficial effects on memory acquisition and retention time compared to Control group; especially retention time had significantly (P < 0.05 increased in exercised group. (2 Chronic stress with and without synchronized exercise significantly (P < 0.01, P < 0.05, respectively impaired acquisition and retention time. (3 Body weight differences were significantly (P < 0.01, P < 0.001 and P < 0.001 lower than Control group in exercise, stress and synchronized exercise with stress groups, respectively. (4 Adverse effects of restraint stress (psychical stress were probably greater than physical activity effects on learning, memory and weight loss. Conclusions: The data confirmed that synchronized exercise with stress had not significantly protective role in improvement of passive avoidance acquisition and retention time; hence it did not significantly improve learning and memory deficit in stressed rats; whereas exercise alone could improve memory deficit in rats.

  9. Learning and extinction of a passive avoidance response in mice with high levels of predisposition to catalepsy.

    Science.gov (United States)

    Dubrovina, N I; Zinov'ev, D R; Zinov'eva, D V; Kulikov, A V

    2009-06-01

    This report presents results obtained from comparative analysis of learning and the dynamics of extinction of a conditioned passive avoidance response in ASC mice, which were bred for a high level of predisposition to catalepsy, and in CBA and AKR mice. The following findings were obtained: 1) impairments to the extinction of the memory of fear represent an important symptom of depression in ASC mice; 2) extinction is delayed in CBA mice; and 3) new inhibitory learning occurs quickly in AKR mice. Prolonged retention of the fear memory in ASC mice appears to be related to increased anxiety on prolonged testing without a punishment. The deficit of inhibition of the fear reaction in ASC mice allows this strain to be regarded as a genetic model of depression.

  10. Learning and extinction of a passive avoidance response in mice with high levels of predisposition to catalepsy.

    Science.gov (United States)

    Dubrovina, N I; Zinov'ev, D R; Zinov'eva, D V; Kulikov, A V

    2009-06-01

    This report presents results obtained from comparative analysis of learning and the dynamics of extinction of a conditioned passive avoidance response in ASC mice, which were bred for a high level of predisposition to catalepsy, and in CBA and AKR mice. The following findings were obtained: 1) impairments to the extinction of the memory of fear represent an important symptom of depression in ASC mice; 2) extinction is delayed in CBA mice; and 3) new inhibitory learning occurs quickly in AKR mice. Prolonged retention of the fear memory in ASC mice appears to be related to increased anxiety on prolonged testing without a punishment. The deficit of inhibition of the fear reaction in ASC mice allows this strain to be regarded as a genetic model of depression. PMID:19430979

  11. Estradiol to aged female or male mice improves learning in inhibitory avoidance and water maze tasks

    OpenAIRE

    Frye, Cheryl A.; Rhodes, Madeline E; Dudek, Bruce

    2005-01-01

    Although 17β-Estradiol (E2) improves cognitive performance of aged female mice, its mnemonic effects when administered post-training to aged male mice have not been examined. E2 (10 µg, SC) or oil vehicle was administered to intact, 24-month-old female or male congenic (primarily C57BL/6 background) mice immediately after training in the inhibitory avoidance or water maze tasks. Following behavioral testing, effects of 1 or 24 h of E2 exposure on hippocampal levels of E2 and brain-derived neu...

  12. Pharmacological differences between memory consolidation of habituation to an open field and inhibitory avoidance learning

    Directory of Open Access Journals (Sweden)

    Vianna M.R.M.

    2001-01-01

    Full Text Available Rats implanted bilaterally with cannulae in the CA1 region of the dorsal hippocampus or the entorhinal cortex were submitted to either a one-trial inhibitory avoidance task, or to 5 min of habituation to an open field. Immediately after training, they received intrahippocampal or intraentorhinal 0.5-µl infusions of saline, of a vehicle (2% dimethylsulfoxide in saline, of the glutamatergic N-methyl-D-aspartate (NMDA receptor antagonist 2-amino-5-phosphono pentanoic acid (AP5, of the protein kinase A inhibitor Rp-cAMPs (0.5 µg/side, of the calcium-calmodulin protein kinase II inhibitor KN-62, of the dopaminergic D1 antagonist SCH23390, or of the mitogen-activated protein kinase kinase inhibitor PD098059. Animals were tested in each task 24 h after training. Intrahippocampal KN-62 was amnestic for habituation; none of the other treatments had any effect on the retention of this task. In contrast, all of them strongly affected memory of the avoidance task. Intrahippocampal Rp-cAMPs, KN-62 and AP5, and intraentorhinal Rp-cAMPs, KN-62, PD098059 and SCH23390 caused retrograde amnesia. In view of the known actions of the treatments used, the present findings point to important biochemical differences in memory consolidation processes of the two tasks.

  13. Effect of central muscarinic receptors on passive-avoidance learning deficits induced by prenatal pentylenetetrazol kindling in male offspring.

    Science.gov (United States)

    Pourmotabbed, A; Mahmoodi, G; Mahmoodi, S; Mohammadi-Farani, A; Nedaei, S E; Pourmotabbed, T; Pourmotabbed, T

    2014-10-24

    Occurrence of the epileptic seizures during gestation might affect the neurodevelopment of the fetus resulting in cognitive problems for the child later in life. We have previously reported that prenatal pentylenetetrazol (PTZ)-kindling induces learning and memory deficits in the children born to kindled mothers, later in life but the mechanisms involved in this processes are unknown. The cholinergic system plays a major role in learning and memory. The present study was performed to investigate the possible involvement of central muscarinic cholinergic receptors on learning and memory deficits induced by prenatal PTZ-kindling in male offspring. Pregnant Wistar rats were kindled by repetitive i.p. injection of 25mg/kg of PTZ on day 13 of their pregnancy. The effect of intracerebroventricular (ICV) microinjection of scopolamine and pilocarpine, muscarinic cholinergic receptors antagonist and agonist, respectively on passive-avoidance learning of pups were tested at 12weeks of age using shuttle-box apparatus. Our data showed that the retention latencies of pups that received scopolamine (2 or 3μg) were significantly reduced compared to those received normal saline (pkindled dams and suggest a central mechanism for the cognitive and memory dysfunction, associated with seizures during pregnancy.

  14. Comparing different approach and avoidance models of learning and personality in the prediction of work, university, and leadership outcomes.

    Science.gov (United States)

    Jackson, Chris J; Hobman, Elizabeth V; Jimmieson, Nerina L; Martin, Robin

    2009-05-01

    Jackson (2005) developed a hybrid model of personality and learning, known as the learning styles profiler (LSP) which was designed to span biological, socio-cognitive, and experiential research foci of personality and learning research. The hybrid model argues that functional and dysfunctional learning outcomes can be best understood in terms of how cognitions and experiences control, discipline, and re-express the biologically based scale of sensation-seeking. In two studies with part-time workers undertaking tertiary education (N = 137 and 58), established models of approach and avoidance from each of the three different research foci were compared with Jackson's hybrid model in their predictiveness of leadership, work, and university outcomes using self-report and supervisor ratings. Results showed that the hybrid model was generally optimal and, as hypothesized, that goal orientation was a mediator of sensation-seeking on outcomes (work performance, university performance, leader behaviours, and counterproductive work behaviour). Our studies suggest that the hybrid model has considerable promise as a predictor of work and educational outcomes as well as dysfunctional outcomes.

  15. Cysteamine and pantethine effects on passive avoidance behavior, shuttle box learning, open-field activity, striatal catecholamines and somatostatin.

    Science.gov (United States)

    Vécsei, L; Widerlöv, E; Ekman, R; Alling, C

    1989-01-01

    The effects of cysteamine and pantethine were compared on different behavioral tests and neurochemical parameters in rats. Cysteamine, administered in high dose (3.90 mM/kg s.c.), decreased the locomotor and rearing activities of rats, while it slightly but not significantly increased the avoidance latency in a passive avoidance test. Pantethine, 24 hr after its administration, significantly increased the dihydroxyphenyl acetic acid (DOPAC) levels in the striatum. Cysteamine slightly reduced the DOPAC level without influencing the catecholamine levels in this brain area. The striatal somatostatin concentration was reduced 24 hr after the administration of cysteamine, while pantethine did not influence it. After repeated daily injections of pantethine, the drug facilitated the shuttle box learning process and increased the intertrial and open-field activities of the animals. Cysteamine only slightly increased the locomotion and rearing and did not influence the shuttle box learning. Both pantethine and cysteamine slowed the rate of the "body weight increase" of the animals when compared to a saline-treated group. These findings suggest that the locomotor activation induced by pantethine 24 hr after its administration plays an important role in its behavioral effects. It might be that the striatal dopaminergic transmission, modified by administration of pantethine, plays some role in the higher locomotor activity induced by the substance. PMID:2570553

  16. The Effect of Treadmill Running on Passive Avoidance Learning in Animal Model of Alzheimer Disease

    OpenAIRE

    Nasrin Hosseini; Hojjatallah Alaei; Parham Reisi; Maryam Radahmadi

    2013-01-01

    Background : Alzheimer′s disease was known as a progressive neurodegenerative disorder in the elderly and is characterized by dementia and severe neuronal loss in the some regions of brain such as nucleus basalis magnocellularis. It plays an important role in the brain functions such as learning and memory. Loss of cholinergic neurons of nucleus basalis magnocellularis by ibotenic acid can commonly be regarded as a suitable model of Alzheimer′s disease. Previous studies reported that exercise...

  17. Obstacle avoidance during human walking: learning rate and cross-modal transfer.

    Science.gov (United States)

    Erni, T; Dietz, V

    2001-07-01

    1. The aim of this study was to investigate the significance of specific afferent information during motor learning. Blindfolded subjects stepped over an obstacle on a treadmill while different stimuli (acoustic (ACU), somatosensory (SOM) and light flash (LED)) signalled the approaching obstacle. The effect of the above stimuli was then evaluated and compared to full vision (VIS) locomotion. In the non-visual conditions feedback information about the performance was provided by an acoustic signal. 2. Using each of the different stimuli for information the level of subject performance was assessed by noting foot clearance and analysing both leg muscle electromyographic activity and movement trajectories during three successive runs. Each of these runs consisted of 100 steps over the obstacle. 3. The best performance at the onset of the first run was achieved during the VIS condition. When the VIS condition (run 1 + 2) was followed by ACU or SOM information or when the ACU condition (run 1 + 2) was followed by LED, little cross-modal transfer (CMT) occurred, i.e. adaptation in run 3 started again at a low level of performance. In contrast, if adaptation started with ACU stimuli followed by SOM stimuli, almost full CMT occurred. The absolute level of performance achieved after the second or third runs was similar in the VIS and non-VIS conditions. 4. In conclusion, the course of motor learning depends on specific afferent information, and feedforward control has a special influence on the performance only at the onset of the experiment but not on the rate of learning. The fact that little CMT occurs from visual to non-visual stimuli and from ACU to LED suggests that visual afferent input is processed in a different way to non-visual stimuli.

  18. Defensive copers show a deficit in passive avoidance learning on Newman's go/no-go task: implications for self-deception and socialization.

    Science.gov (United States)

    Shane, Matthew S; Peterson, Jordan B

    2004-10-01

    The present study investigated whether passive avoidance learning was retarded by defensive coping strategies designed to minimize exposure to negatively valenced stimuli. High-anxious individuals, low-anxious individuals, and defensive copers completed a computerized go/no-go task, in which they learned when to press or not to press a button, in response to contingent positive and negative feedback. The duration that feedback remained onscreen was self-regulated. Defensive copers showed preferential reflection away from negative feedback, committed more passive-avoidance errors, and were characterized by impaired learning, overall. Further, the ratio of reflection on negative feedback to reflection on positive feedback directly mediated both passive-avoidance errors and overall learning. Defensive coping strategies, therefore, appear to interfere with passive avoidance learning, thereby fostering perseverative, dysfunctional action patterns by reducing knowledge gained from previous mistakes. Implications for the learning of effective socialization strategies, and for psychopathy-which is commonly characterized by similar passive-avoidance deficits-are subsequently considered. PMID:15335333

  19. Histamine in the basolateral amygdala promotes inhibitory avoidance learning independently of hippocampus

    Science.gov (United States)

    Benetti, Fernando; Furini, Cristiane Regina Guerino; de Carvalho Myskiw, Jociane; Provensi, Gustavo; Passani, Maria Beatrice; Baldi, Elisabetta; Bucherelli, Corrado; Munari, Leonardo; Izquierdo, Ivan; Blandina, Patrizio

    2015-01-01

    Recent discoveries demonstrated that recruitment of alternative brain circuits permits compensation of memory impairments following damage to brain regions specialized in integrating and/or storing specific memories, including both dorsal hippocampus and basolateral amygdala (BLA). Here, we first report that the integrity of the brain histaminergic system is necessary for long-term, but not for short-term memory of step-down inhibitory avoidance (IA). Second, we found that phosphorylation of cyclic adenosine monophosphate (cAMP) responsive-element-binding protein, a crucial mediator in long-term memory formation, correlated anatomically and temporally with histamine-induced memory retrieval, showing the active involvement of histamine function in CA1 and BLA in different phases of memory consolidation. Third, we found that exogenous application of histamine in either hippocampal CA1 or BLA of brain histamine-depleted rats, hence amnesic, restored long-term memory; however, the time frame of memory rescue was different for the two brain structures, short lived (immediately posttraining) for BLA, long lasting (up to 6 h) for the CA1. Moreover, long-term memory was formed immediately after training restoring of histamine transmission only in the BLA. These findings reveal the essential role of histaminergic neurotransmission to provide the brain with the plasticity necessary to ensure memorization of emotionally salient events, through recruitment of alternative circuits. Hence, our findings indicate that the histaminergic system comprises parallel, coordinated pathways that provide compensatory plasticity when one brain structure is compromised. PMID:25918368

  20. Histamine in the basolateral amygdala promotes inhibitory avoidance learning independently of hippocampus.

    Science.gov (United States)

    Benetti, Fernando; Furini, Cristiane Regina Guerino; de Carvalho Myskiw, Jociane; Provensi, Gustavo; Passani, Maria Beatrice; Baldi, Elisabetta; Bucherelli, Corrado; Munari, Leonardo; Izquierdo, Ivan; Blandina, Patrizio

    2015-05-12

    Recent discoveries demonstrated that recruitment of alternative brain circuits permits compensation of memory impairments following damage to brain regions specialized in integrating and/or storing specific memories, including both dorsal hippocampus and basolateral amygdala (BLA). Here, we first report that the integrity of the brain histaminergic system is necessary for long-term, but not for short-term memory of step-down inhibitory avoidance (IA). Second, we found that phosphorylation of cyclic adenosine monophosphate (cAMP) responsive-element-binding protein, a crucial mediator in long-term memory formation, correlated anatomically and temporally with histamine-induced memory retrieval, showing the active involvement of histamine function in CA1 and BLA in different phases of memory consolidation. Third, we found that exogenous application of histamine in either hippocampal CA1 or BLA of brain histamine-depleted rats, hence amnesic, restored long-term memory; however, the time frame of memory rescue was different for the two brain structures, short lived (immediately posttraining) for BLA, long lasting (up to 6 h) for the CA1. Moreover, long-term memory was formed immediately after training restoring of histamine transmission only in the BLA. These findings reveal the essential role of histaminergic neurotransmission to provide the brain with the plasticity necessary to ensure memorization of emotionally salient events, through recruitment of alternative circuits. Hence, our findings indicate that the histaminergic system comprises parallel, coordinated pathways that provide compensatory plasticity when one brain structure is compromised. PMID:25918368

  1. Muscarinic receptor binding increases in anterior thalamus and cingulate cortex during discriminative avoidance learning

    International Nuclear Information System (INIS)

    Training-induced neuronal activity develops in the mammalian limbic system during discriminative avoidance conditioning. This study explores behaviorally relevant changes in muscarinic ACh receptor binding in 52 rabbits that were trained to one of five stages of conditioned response acquisition. Sixteen naive and 10 animals yoked to criterion performance served as control cases. Upon reaching a particular stage of training, the brains were removed and autoradiographically assayed for 3H-oxotremorine-M binding with 50 nM pirenzepine (OxO-M/PZ) or for 3H-pirenzepine binding in nine limbic thalamic nuclei and cingulate cortex. Specific OxO-M/PZ binding increased in the parvocellular division of the anterodorsal nucleus early in training when the animals were first exposed to pairing of the conditional and unconditional stimuli. Elevated binding in this nucleus was maintained throughout subsequent training. In the parvocellular division of the anteroventral nucleus (AVp), OxO-M/PZ binding progressively increased throughout training, reached a peak at the criterion stage of performance, and returned to control values during extinction sessions. Peak OxO-M/PZ binding in AVp was significantly elevated over that for cases yoked to criterion performance. In the magnocellular division of the anteroventral nucleus (AVm), OxO-M/PZ binding was elevated only during criterion performance of the task, and it was unaltered in any other limbic thalamic nuclei. Specific OxO-M/PZ binding was also elevated in most layers in rostral area 29c when subjects first performed a significant behavioral discrimination. Training-induced alterations in OxO-M/PZ binding in AVp and layer Ia of area 29c were similar and highly correlated

  2. The activation of histamine-sensitive sites of the ventral hippocampus modulates the consolidation of a learned active avoidance response in rats.

    Science.gov (United States)

    Alvarez, Edgardo O; Banzan, Arturo M

    2008-05-16

    Previous evidence from our laboratory has shown that histamine receptors located into the ventral hippocampus modulate learning and memory processes. Stimulation of histamine hippocampal sensitive receptors during the acquisition phase of a conditioned avoidance response to an ultrasonic tone was able to increase latency to escape and impair memory in the rat. Histamine application into the same hippocampal region also impaired the evocation of the response. The purpose of the present work was to evaluate if histaminergic neuron circuits have participation on the consolidation processes of the conditioned avoiding response. Male adult rats were implanted into the ventral hippocampus with microinjection cannulae and subjected consecutively to 2 sessions of 8 trials to learn an avoidance response after an ultrasonic tone of 40 kHz was on, as it was previously described. Immediately after the training period was over, or 15 min after, different groups of rats were microinjected with saline, histamine or a combination of histamine H(1)- or H(2)-receptor antagonists. Twenty four hours later, animals were tested in a new session for the retention of the avoiding response. Results showed that histamine treatment interfered with the consolidation of the avoiding response, affecting latency and the memory efficiency. This interference was mediated by histamine H(1)- and H(2)-receptors, since pretreatment with pyrilamine or ranitidine blocked the inhibitory effect of histamine. Results support the concept that histaminergic neurotransmission modulates learning and memory by affecting selectively the three stages of learning.

  3. The roles of the nucleus accumbens core, dorsomedial striatum, and dorsolateral striatum in learning: performance and extinction of Pavlovian fear-conditioned responses and instrumental avoidance responses.

    Science.gov (United States)

    Wendler, Etieli; Gaspar, Jessica C C; Ferreira, Tatiana L; Barbiero, Janaína K; Andreatini, Roberto; Vital, Maria A B F; Blaha, Charles D; Winn, Philip; Da Cunha, Claudio

    2014-03-01

    This study examined the effects of bilateral excitotoxic lesions of the nucleus accumbens core (NAc-co), dorsomedial striatum (DMS) or dorsolateral striatum (DLS) of rats on the learning and extinction of Pavlovian and instrumental components of conditioned avoidance responses (CARs). None of the lesions caused sensorimotor deficits that could affect locomotion. Lesions of the NAc-co, but not DMS or DLS, decreased unconditioned and conditioned freezing. The NAc-co and DLS lesioned rats learned the 2-way active avoidance task more slowly. These results suggest: (i) CARs depend on both Pavlovian and instrumental learning; (ii) learning the Pavlovian component of CARs depends on the NAc-co; learning the instrumental component of CARs depends on the DLS, NAc and DMS; (iii) although the NAc-co is also needed for learning the instrumental component, it is not clear whether it plays a role in learning the instrumental component per se or if it simply allows learning of the Pavlovian component which is a pre-condition for learning the instrumental component; (iv) we did not find evidence that the DMS and DLS play the same roles in habit and goal-directed aspects of the instrumental component of CARs as observed in appetitive motivated instrumental responding.

  4. Ultrasonic vocalization ratios reflect the influence of motivational state and amygdala lesions on different types of taste avoidance learning.

    Science.gov (United States)

    Hamdani, Selma; White, Norman M

    2011-02-01

    Consumption of a sweet solution (the CS) and ultrasonic vocalizations (USVs) emitted by rats were recorded in a conditioned taste avoidance paradigm. The rats' affective states were inferred from a ratio of high to low-frequency ultrasonic calls, which have been associated with positive and negative affect, respectively. The interacting effects of deprivation state and lesions of the basolateral amygdala (BLA) on CS consumption and affective state were examined. Rats were trained during the light phase while either 23 h or 3h water deprived by exposing them to the CS and then injecting them with LiCl or saline. They were tested by re-exposing them to the CS while either 23 or 3h deprived. Sham-lesioned rats that received LiCl injections consumed significantly less of the CS and evidenced relatively negative affect (inferred from the USV ratio) compared to control rats that received saline injections, regardless of the deprivation state in which they were trained or tested. Rats with BLA lesions trained while 23 h deprived failed to exhibit either reduced consumption or negative affect, regardless of whether they were tested while deprived for 23 or 3h. Identical lesions had no effect on reduced consumption or on negative affect in rats trained while 3h deprived, regardless of whether they were tested while deprived for 3 or 23 h. The findings suggest that both reduced consumption and negative affect are the results of different learning processes in deprived (23 h) and nearly satiated (3h, during the light phase) rats. The amygdala-dependent negative affective shift observed in deprived rats may be due to an aversive Pavlovian conditioned response that acts to suppress drinking. The amygdala-independent negative affective response and reduced consumption in nearly satiated rats could be due to a form of latent learning of a stimulus-outcome association. PMID:20888864

  5. Dizocilpine (MK-801) impairs learning in the active place avoidance task but has no effect on the performance during task/context alternation.

    Science.gov (United States)

    Vojtechova, Iveta; Petrasek, Tomas; Hatalova, Hana; Pistikova, Adela; Vales, Karel; Stuchlik, Ales

    2016-05-15

    The prevention of engram interference, pattern separation, flexibility, cognitive coordination and spatial navigation are usually studied separately at the behavioral level. Impairment in executive functions is often observed in patients suffering from schizophrenia. We have designed a protocol for assessing these functions all together as behavioral separation. This protocol is based on alternated or sequential training in two tasks testing different hippocampal functions (the Morris water maze and active place avoidance), and alternated or sequential training in two similar environments of the active place avoidance task. In Experiment 1, we tested, in adult rats, whether the performance in two different spatial tasks was affected by their order in sequential learning, or by their day-to-day alternation. In Experiment 2, rats learned to solve the active place avoidance task in two environments either alternately or sequentially. We found that rats are able to acquire both tasks and to discriminate both similar contexts without obvious problems regardless of the order or the alternation. We used two groups of rats, controls and a rat model of psychosis induced by a subchronic intraperitoneal application of 0.08mg/kg of dizocilpine (MK-801), a non-competitive antagonist of NMDA receptors. Dizocilpine had no selective effect on parallel/sequential learning of tasks/contexts. However, it caused hyperlocomotion and a significant deficit in learning in the active place avoidance task regardless of the task alternation. Cognitive coordination tested by this task is probably more sensitive to dizocilpine than spatial orientation because no hyperactivity or learning impairment was observed in the Morris water maze. PMID:26970577

  6. Learning to obtain reward, but not avoid punishment, is affected by presence of PTSD symptoms in male veterans: empirical data and computational model.

    Directory of Open Access Journals (Sweden)

    Catherine E Myers

    Full Text Available Post-traumatic stress disorder (PTSD symptoms include behavioral avoidance which is acquired and tends to increase with time. This avoidance may represent a general learning bias; indeed, individuals with PTSD are often faster than controls on acquiring conditioned responses based on physiologically-aversive feedback. However, it is not clear whether this learning bias extends to cognitive feedback, or to learning from both reward and punishment. Here, male veterans with self-reported current, severe PTSD symptoms (PTSS group or with few or no PTSD symptoms (control group completed a probabilistic classification task that included both reward-based and punishment-based trials, where feedback could take the form of reward, punishment, or an ambiguous "no-feedback" outcome that could signal either successful avoidance of punishment or failure to obtain reward. The PTSS group outperformed the control group in total points obtained; the PTSS group specifically performed better than the control group on reward-based trials, with no difference on punishment-based trials. To better understand possible mechanisms underlying observed performance, we used a reinforcement learning model of the task, and applied maximum likelihood estimation techniques to derive estimated parameters describing individual participants' behavior. Estimations of the reinforcement value of the no-feedback outcome were significantly greater in the control group than the PTSS group, suggesting that the control group was more likely to value this outcome as positively reinforcing (i.e., signaling successful avoidance of punishment. This is consistent with the control group's generally poorer performance on reward trials, where reward feedback was to be obtained in preference to the no-feedback outcome. Differences in the interpretation of ambiguous feedback may contribute to the facilitated reinforcement learning often observed in PTSD patients, and may in turn provide new insight

  7. Learning to obtain reward, but not avoid punishment, is affected by presence of PTSD symptoms in male veterans: empirical data and computational model.

    Science.gov (United States)

    Myers, Catherine E; Moustafa, Ahmed A; Sheynin, Jony; Vanmeenen, Kirsten M; Gilbertson, Mark W; Orr, Scott P; Beck, Kevin D; Pang, Kevin C H; Servatius, Richard J

    2013-01-01

    Post-traumatic stress disorder (PTSD) symptoms include behavioral avoidance which is acquired and tends to increase with time. This avoidance may represent a general learning bias; indeed, individuals with PTSD are often faster than controls on acquiring conditioned responses based on physiologically-aversive feedback. However, it is not clear whether this learning bias extends to cognitive feedback, or to learning from both reward and punishment. Here, male veterans with self-reported current, severe PTSD symptoms (PTSS group) or with few or no PTSD symptoms (control group) completed a probabilistic classification task that included both reward-based and punishment-based trials, where feedback could take the form of reward, punishment, or an ambiguous "no-feedback" outcome that could signal either successful avoidance of punishment or failure to obtain reward. The PTSS group outperformed the control group in total points obtained; the PTSS group specifically performed better than the control group on reward-based trials, with no difference on punishment-based trials. To better understand possible mechanisms underlying observed performance, we used a reinforcement learning model of the task, and applied maximum likelihood estimation techniques to derive estimated parameters describing individual participants' behavior. Estimations of the reinforcement value of the no-feedback outcome were significantly greater in the control group than the PTSS group, suggesting that the control group was more likely to value this outcome as positively reinforcing (i.e., signaling successful avoidance of punishment). This is consistent with the control group's generally poorer performance on reward trials, where reward feedback was to be obtained in preference to the no-feedback outcome. Differences in the interpretation of ambiguous feedback may contribute to the facilitated reinforcement learning often observed in PTSD patients, and may in turn provide new insight into how

  8. Signaled two-way avoidance learning using electrical stimulation of the inferior colliculus as negative reinforcement: effects of visual and auditory cues as warning stimuli

    Directory of Open Access Journals (Sweden)

    A.C. Troncoso

    1998-03-01

    Full Text Available The inferior colliculus is a primary relay for the processing of auditory information in the brainstem. The inferior colliculus is also part of the so-called brain aversion system as animals learn to switch off the electrical stimulation of this structure. The purpose of the present study was to determine whether associative learning occurs between aversion induced by electrical stimulation of the inferior colliculus and visual and auditory warning stimuli. Rats implanted with electrodes into the central nucleus of the inferior colliculus were placed inside an open-field and thresholds for the escape response to electrical stimulation of the inferior colliculus were determined. The rats were then placed inside a shuttle-box and submitted to a two-way avoidance paradigm. Electrical stimulation of the inferior colliculus at the escape threshold (98.12 ± 6.15 (A, peak-to-peak was used as negative reinforcement and light or tone as the warning stimulus. Each session consisted of 50 trials and was divided into two segments of 25 trials in order to determine the learning rate of the animals during the sessions. The rats learned to avoid the inferior colliculus stimulation when light was used as the warning stimulus (13.25 ± 0.60 s and 8.63 ± 0.93 s for latencies and 12.5 ± 2.04 and 19.62 ± 1.65 for frequencies in the first and second halves of the sessions, respectively, P0.05 in both cases. Taken together, the present results suggest that rats learn to avoid the inferior colliculus stimulation when light is used as the warning stimulus. However, this learning process does not occur when the neutral stimulus used is an acoustic one. Electrical stimulation of the inferior colliculus may disturb the signal transmission of the stimulus to be conditioned from the inferior colliculus to higher brain structures such as amygdala

  9. Absence of “Warm-Up” during Active Avoidance Learning in a Rat Model of Anxiety Vulnerability: Insights from Computational Modeling

    Science.gov (United States)

    Myers, Catherine E.; Smith, Ian M.; Servatius, Richard J.; Beck, Kevin D.

    2014-01-01

    Avoidance behaviors, in which a learned response causes omission of an upcoming punisher, are a core feature of many psychiatric disorders. While reinforcement learning (RL) models have been widely used to study the development of appetitive behaviors, less attention has been paid to avoidance. Here, we present a RL model of lever-press avoidance learning in Sprague-Dawley (SD) rats and in the inbred Wistar Kyoto (WKY) rat, which has been proposed as a model of anxiety vulnerability. We focus on “warm-up,” transiently decreased avoidance responding at the start of a testing session, which is shown by SD but not WKY rats. We first show that a RL model can correctly simulate key aspects of acquisition, extinction, and warm-up in SD rats; we then show that WKY behavior can be simulated by altering three model parameters, which respectively govern the tendency to explore new behaviors vs. exploit previously reinforced ones, the tendency to repeat previous behaviors regardless of reinforcement, and the learning rate for predicting future outcomes. This suggests that several, dissociable mechanisms may contribute independently to strain differences in behavior. The model predicts that, if the “standard” inter-session interval is shortened from 48 to 24 h, SD rats (but not WKY) will continue to show warm-up; we confirm this prediction in an empirical study with SD and WKY rats. The model further predicts that SD rats will continue to show warm-up with inter-session intervals as short as a few minutes, while WKY rats will not show warm-up, even with inter-session intervals as long as a month. Together, the modeling and empirical data indicate that strain differences in warm-up are qualitative rather than just the result of differential sensitivity to task variables. Understanding the mechanisms that govern expression of warm-up behavior in avoidance may lead to better understanding of pathological avoidance, and potential pathways to modify these processes. PMID

  10. Algorithm of multi-robot collision avoidance based on reinforcement learning%基于强化学习的多机器人避碰算法研究

    Institute of Scientific and Technical Information of China (English)

    段勇; 陈腾峰

    2012-01-01

    This paper adopts reinforcement learning to solve multi-robot collision avoidance problems. Then in allusion to the insufficiency that tabular Q-leaming algorithm can only be used for discrete states and learning time is too long, difficult to convergence, it puts forward combination of neural networks and Q-leaming algorithms. Finally the algorithm is applied to multi-robot collision avoidance problems. The simulation experiments show that the algorithm is effective and well solve the multi-robot collision avoidance problems.%采用强化学习解决多机器人避碰问题.然后针对表格式Q学习算法只能用于离散的状态并且学习时间过长,难以收敛的不足,提出了神经网络和Q学习相结合的算法.最后将该算法应用到多机器人避碰问题中,仿真实验表明该算法有效,能较好地解决多机器人避碰问题.

  11. Unpredictable chronic stress decreases inhibitory avoidance learning in Tuebingen long-fin zebrafish: stronger effects in the resting phase than in the active phase.

    Science.gov (United States)

    Manuel, Remy; Gorissen, Marnix; Zethof, Jan; Ebbesson, Lars O E; van de Vis, Hans; Flik, Gert; van den Bos, Ruud

    2014-11-01

    Zebrafish (Danio rerio Hamilton) are increasingly used as a model to study the effects of chronic stress on brain and behaviour. In rodents, unpredictable chronic stress (UCS) has a stronger effect on physiology and behaviour during the active phase than during the resting phase. Here, we applied UCS during the daytime (active phase) for 7 and 14 days or during the night-time (resting phase) for 7 nights in an in-house-reared Tuebingen long-fin (TLF) zebrafish strain. Following UCS, inhibitory avoidance learning was assessed using a 3 day protocol where fish learn to avoid swimming from a white to a black compartment where they will receive a 3 V shock. Latencies of entering the black compartment were recorded before training (day 1; first shock) and after training on day 2 (second shock) and day 3 (no shock, tissue sampling). Fish whole-body cortisol content and expression levels of genes related to stress, fear and anxiety in the telencephalon were quantified. Following 14 days of UCS during the day, inhibitory avoidance learning decreased (lower latencies on days 2 and 3); minor effects were found following 7 days of UCS. Following 7 nights of UCS, inhibitory avoidance learning decreased (lower latency on day 3). Whole-body cortisol levels showed a steady increase compared with controls (100%) from 7 days of UCS (139%), to 14 days of UCS (174%) to 7 nights of UCS (231%), suggestive of an increasing stress load. Only in the 7 nights of UCS group did expression levels of corticoid receptor genes (mr, grα, grβ) and of bdnf increase. These changes are discussed as adaptive mechanisms to maintain neuronal integrity and prevent overload, and as being indicative of a state of high stress load. Overall, our data suggest that stressors during the resting phase have a stronger impact than during the active phase. Our data warrant further studies on the effect of UCS on stress axis-related genes, especially grβ; in mammals this receptor has been implicated in

  12. Avoid Logs to Avoid Ticks

    Institute of Scientific and Technical Information of China (English)

    莫文佳

    2004-01-01

    扁虱是莱姆关节炎的罪魁祸首。研究人员为了弄明白何处扁虱最猖獗, 不惜以身作饵,他们发现:The ticks were all over the log surface。因此告诫人 们:Avoid sitting on logs。

  13. Performance Approach-Avoidance Motivation and Planned Behavior Theory: Model Stability With Greek Students With and Without Learning Disabilities

    Science.gov (United States)

    Sideridis, Georgios D.

    2005-01-01

    Two studies evaluated the contribution of goal orientation--over and above the constructs of planned behavior theory--in explaining the relationship between attitudes, motivation, and academic achievement for students with and without learning disabilities. Results indicated that a performance-approach orientation exerted significant positive…

  14. Long-lasting mnemotropic effect of substance P and its N-terminal fragment (SP1-7 on avoidance learning

    Directory of Open Access Journals (Sweden)

    C. Tomaz

    1997-02-01

    Full Text Available We investigated the long-lasting effect of peripheral injection of the neuropeptide substance P (SP and of some N- or C-terminal SP fragments (SPN and SPC, respectively on retention test performance of avoidance learning. Male Wistar rats (220 to 280 g were trained in an inhibitory step-down avoidance task and tested 24 h or 21 days later. Immediately after the training trial rats received an intraperitoneal injection of SP (50 µg/kg, SPN 1-7 (167 µg/kg or SPC 7-11 (134 µg/kg. Control groups were injected with vehicle or SP 5 h after the training trial. The immediate post-training administration of SP and SPN, but not SPC, facilitated avoidance behavior in rats tested 24 h or 21 days later, i.e., the retention test latencies of the SP and SPN groups were significantly longer (P<0.05, Mann-Whitney U-test during both training-test intervals. These observations suggest that the memory-enhancing effect of SP is long-lasting and that the amino acid sequence responsible for this effect is encoded by its N-terminal part

  15. The Global Role of Health Care Delivery Science: Learning from Variation to Build Health Systems that Avoid Waste and Harm

    OpenAIRE

    Mulley, Albert G.

    2013-01-01

    This paper addresses the fourth theme of the Indiana Global Health Research Working Conference, Clinical Effectiveness and Health Systems Research. It explores geographic variation in health care delivery and health outcomes as a source of learning how to achieve better health outcomes at lower cost. It focuses particularly on the relationship between investments made in capacities to deliver different health care services to a population and the value thereby created by that care for individ...

  16. The global role of health care delivery science: learning from variation to build health systems that avoid waste and harm.

    Science.gov (United States)

    Mulley, Albert G

    2013-09-01

    This paper addresses the fourth theme of the Indiana Global Health Research Working Conference, Clinical Effectiveness and Health Systems Research. It explores geographic variation in health care delivery and health outcomes as a source of learning how to achieve better health outcomes at lower cost. It focuses particularly on the relationship between investments made in capacities to deliver different health care services to a population and the value thereby created by that care for individual patients. The framing begins with the dramatic variation in per capita health care expenditures across the nations of the world, which is largely explained by variations in national wealth. The 1978 Declaration of Alma Ata is briefly noted as a response to such inequities with great promise that has not as yet been realized. This failure to realize the promise of Alma Ata grows in significance with the increasing momentum for universal health coverage that is emerging in the current global debate about post-2015 development goals. Drawing upon work done at Dartmouth over more than three decades, the framing then turns to within-country variations in per capita expenditures, utilization of different services, and health outcomes. A case is made for greater attention to the question of value by bringing better information to bear at both the population and individual levels. Specific opportunities to identify and reduce waste in health care, and the harm that is so often associated with it, are identified by learning from outcome variations and practice variations. PMID:23797914

  17. The global role of health care delivery science: learning from variation to build health systems that avoid waste and harm.

    Science.gov (United States)

    Mulley, Albert G

    2013-09-01

    This paper addresses the fourth theme of the Indiana Global Health Research Working Conference, Clinical Effectiveness and Health Systems Research. It explores geographic variation in health care delivery and health outcomes as a source of learning how to achieve better health outcomes at lower cost. It focuses particularly on the relationship between investments made in capacities to deliver different health care services to a population and the value thereby created by that care for individual patients. The framing begins with the dramatic variation in per capita health care expenditures across the nations of the world, which is largely explained by variations in national wealth. The 1978 Declaration of Alma Ata is briefly noted as a response to such inequities with great promise that has not as yet been realized. This failure to realize the promise of Alma Ata grows in significance with the increasing momentum for universal health coverage that is emerging in the current global debate about post-2015 development goals. Drawing upon work done at Dartmouth over more than three decades, the framing then turns to within-country variations in per capita expenditures, utilization of different services, and health outcomes. A case is made for greater attention to the question of value by bringing better information to bear at both the population and individual levels. Specific opportunities to identify and reduce waste in health care, and the harm that is so often associated with it, are identified by learning from outcome variations and practice variations.

  18. Triumph of hope over experience: learning from interventions to reduce avoidable hospital admissions identified through an Academic Health and Social Care Network

    Directory of Open Access Journals (Sweden)

    Woodhams Victoria

    2012-06-01

    Full Text Available Abstract Background Internationally health services are facing increasing demands due to new and more expensive health technologies and treatments, coupled with the needs of an ageing population. Reducing avoidable use of expensive secondary care services, especially high cost admissions where no procedure is carried out, has become a focus for the commissioners of healthcare. Method We set out to identify, evaluate and share learning about interventions to reduce avoidable hospital admission across a regional Academic Health and Social Care Network (AHSN. We conducted a service evaluation identifying initiatives that had taken place across the AHSN. This comprised a literature review, case studies, and two workshops. Results We identified three types of intervention: pre-hospital; within the emergency department (ED; and post-admission evaluation of appropriateness. Pre-hospital interventions included the use of predictive modelling tools (PARR – Patients at risk of readmission and ACG – Adjusted Clinical Groups sometimes supported by community matrons or virtual wards. GP-advisers and outreach nurses were employed within the ED. The principal post-hoc interventions were the audit of records in primary care or the application of the Appropriateness Evaluation Protocol (AEP within the admission ward. Overall there was a shortage of independent evaluation and limited evidence that each intervention had an impact on rates of admission. Conclusions Despite the frequency and cost of emergency admission there has been little independent evaluation of interventions to reduce avoidable admission. Commissioners of healthcare should consider interventions at all stages of the admission pathway, including regular audit, to ensure admission thresholds don’t change.

  19. Fostering assumption-based stress-test thinking in managing groundwater systems: learning to avoid failures due to basic dynamics

    Science.gov (United States)

    Guillaume, Joseph H. A.; El Sawah, Sondoss

    2014-06-01

    Sustainable groundwater resource management can only be achieved if planning processes address the basic dynamics of the groundwater system. Conceptual and distributed groundwater models do not necessarily translate into an understanding of how a plan might operate in reality. Prompted by Australian experiences, `iterative closed-question modelling' has been used to develop a process of iterative dialogue about management options, objectives and knowledge. Simple hypothetical models of basic system dynamics that satisfy agreed assumptions are used to stress-test the ability of a proposed management plan to achieve desired future conditions. Participants learn from models in which a plan succeeds and fails, updating their assumptions, expectations or plan. Their new understanding is tested against further hypothetical models. The models act as intellectual devices that confront users with new scenarios to discuss. This theoretical approach is illustrated using simple one and two-cell groundwater models that convey basic notions of capture and spatial impacts of pumping. Simple extensions can address uncertain climate, managed-aquifer recharge and alternate water sources. Having learnt to address the dynamics captured by these models, participants may be better placed to address local conditions and develop more effective arrangements to achieve management outcomes.

  20. The Effect of Chronic Oral Administration of Withania Somnifera Root on Learning and Memory in Diabetic Rats Using Passive Avoidance Test

    Directory of Open Access Journals (Sweden)

    M. Roghani

    2006-07-01

    Full Text Available Introduction & Objective: Diabetes mellitus (especially type I is accompanied with disturbances in learning, memory, and cognitive skills in the human society and experimental animals. Considering the potential anti-diabetic effect of the medicinal plant Withania somnifera (ashwagandha and the augmenting effect of its consumption on the memory and mental health, this study was conducted to evaluate the effect of chronic oral administration of ashwagandha root on learning and memory in diabetic rats using passive avoidance test. Materials & Methods: For this purpose, male Wistar diabetic rats were randomly divided into control, ashwagandha-treated control, diabetic, and ashwagandha-treated diabetic groups. Ashwagandha treatment continued for 1 to 2 months. For induction of diabetes, streptozotocin was injected i.p. at a single dose of 60 mg/kg. Serum glucose level was determined before the study and at 4th and 8th weeks after the experiment. In addition, for evaluation of learning and memory, initial latency (IL and step-through latency (STL were determined after 1 and 2 months using passive avoidance test. Results: It was found that one- and two-month administration of ashwagandha root at a weight ratio of 1/15 has not any significant hypoglycemic effect in treated control and diabetic groups. Furthermore, there was a significant increase (p<0.05 in IL in diabetic and ashwagandha-treated diabetic groups after two months compared to control group. In this respect, there was no significant difference between diabetic and ashwagandha-treated diabetic groups. In addition, STL significantly increased in ashwagandha-treated control group after 1 (p<0.01 and 2 (p<0.05 month in comparison to control group. On the other hand, STL significantly decreased (p<0.05 in diabetic group and significantly increased (p<0.05 in ashwagandha-treated diabetic group as compared to control group after two months. Conclusion: In summary, chronic oral administration of

  1. Motive to Avoid Success, Locus of Control, and Reinforcement Avoidance.

    Science.gov (United States)

    Katovsky, Walter

    Subjects were four groups of 12 college women, high or low in motive to avoid success (MAS) and locus of control (LC), were reinforced for response A on a fixed partial reinforcement schedule on three concept learning tasks, one task consisting of combined reward and punishment, another of reward only, and one of punishment only. Response B was…

  2. Teachers Avoiding Learners' Avoidance: Is It Possible?

    Science.gov (United States)

    Tadayyon, Maedeh; Zarrinabadi, Nourollah; Ketabi, Saeed

    2016-01-01

    Dealing with learners who prefer to take the back seat and avoid classroom participation can be every teacher's nightmare. This lack of participation may cause teacher frustration, and possibly the only way to reduce this lack of participation is to access the concept of avoidance strategy. Avoidance strategy is the abandonment of a classroom task…

  3. Chemical avoidance responses of fishes.

    Science.gov (United States)

    Tierney, Keith B

    2016-05-01

    The hydrosphere is a repository for all of our waste and mistakes, be they sewage, garbage, process-affected waters, runoff, and gases. For fish living in environments receiving undesirable inputs, moving away seems an obvious way to avoid harm. While this should occur, there are numerous examples where it will not. The inability to avoid harmful environments may lead to sensory impairments that in turn limit the ability to avoid other dangers or locate benefits. For avoidance to occur, the danger must first be perceived, which may not happen if the fish is 'blinded' in some capacity. Second, the danger must be recognized for what it is, which may also not happen if the fish is cognitively confused or impaired. Third, it is possible that the fish may not be able to leave the area, or worse, learns to prefer a toxic environment. Concerning generating regulations around avoidance, there are two possibilities: that an avoidance threshold be used to set guidelines for effluent release with the intention of driving fishes away; the second is to set a contaminant concentration that would not affect the avoidance or attraction responses to other cues. With the complexities of the modern world in which we release diverse pollutants, from light to municipal effluents full of 1000s of chemicals, to the diversity present in ecosystems, it is impossible to have avoidance data on every stimulus-species combination. Nevertheless, we may be able to use existing avoidance response data to predict the likelihood of avoidance of untested stimuli. Where we cannot, this review includes a framework that can be used to direct new research. This review is intended to collate existing avoidance response data, provide a framework for making decisions in the absence of data, and suggest studies that would facilitate the prediction of risk to fish health in environments receiving intentional and unintentional human-based chemical inputs. PMID:26970365

  4. Chemical avoidance responses of fishes.

    Science.gov (United States)

    Tierney, Keith B

    2016-05-01

    The hydrosphere is a repository for all of our waste and mistakes, be they sewage, garbage, process-affected waters, runoff, and gases. For fish living in environments receiving undesirable inputs, moving away seems an obvious way to avoid harm. While this should occur, there are numerous examples where it will not. The inability to avoid harmful environments may lead to sensory impairments that in turn limit the ability to avoid other dangers or locate benefits. For avoidance to occur, the danger must first be perceived, which may not happen if the fish is 'blinded' in some capacity. Second, the danger must be recognized for what it is, which may also not happen if the fish is cognitively confused or impaired. Third, it is possible that the fish may not be able to leave the area, or worse, learns to prefer a toxic environment. Concerning generating regulations around avoidance, there are two possibilities: that an avoidance threshold be used to set guidelines for effluent release with the intention of driving fishes away; the second is to set a contaminant concentration that would not affect the avoidance or attraction responses to other cues. With the complexities of the modern world in which we release diverse pollutants, from light to municipal effluents full of 1000s of chemicals, to the diversity present in ecosystems, it is impossible to have avoidance data on every stimulus-species combination. Nevertheless, we may be able to use existing avoidance response data to predict the likelihood of avoidance of untested stimuli. Where we cannot, this review includes a framework that can be used to direct new research. This review is intended to collate existing avoidance response data, provide a framework for making decisions in the absence of data, and suggest studies that would facilitate the prediction of risk to fish health in environments receiving intentional and unintentional human-based chemical inputs.

  5. Generalization of socially transmitted and instructed avoidance

    Directory of Open Access Journals (Sweden)

    Gemma eCameron

    2015-06-01

    Full Text Available Excessive avoidance behavior, in which an instrumental action prevents an upcoming aversive event, is a defining feature of anxiety disorders. Left unchecked, both fear and avoidance of potentially threatening stimuli may generalize to perceptually related stimuli and situations. The behavioral consequences of generalization mean that aversive learning experiences with specific threats may lead people to infer that classes of related stimuli are threatening, potentially dangerous, and need to be avoided, despite differences in physical form. Little is known about avoidance generalization in humans and the learning pathways by which it may be transmitted. In the present study, we compared two pathways to avoidance, instructions and social observation, on subsequent generalization of avoidance behavior, fear expectancy and physiological arousal. Participants first learned that one cue was a danger cue (conditioned stimulus, CS+ and another was a safety cue (CS-. Groups then were either instructed that a simple avoidance response in the presence of the CS+ cancelled upcoming shock presentations (instructed-learning group or observed a short movie showing a demonstrator performing the avoidance response to prevent shock (observational-learning group. During generalization testing, danger and safety cues were presented along with generalization stimuli that parametrically varied in perceptual similarity to the CS+. Reinstatement of fear and avoidance was also tested. Findings demonstrate, for the first time, generalization of socially transmitted and instructed avoidance: both groups showed comparable generalization gradients in fear expectancy, avoidance behavior and arousal. Return of fear was evident, suggesting that generalized avoidance remains persistent following extinction testing. The utility of the present paradigm for research on avoidance generalization is discussed.

  6. Predator Avoidance in Extremophile Fish

    Directory of Open Access Journals (Sweden)

    Martin Plath

    2013-02-01

    Full Text Available Extreme habitats are often characterized by reduced predation pressures, thus representing refuges for the inhabiting species. The present study was designed to investigate predator avoidance of extremophile populations of Poecilia mexicana and P. sulphuraria that either live in hydrogen sulfide-rich (sulfidic springs or cave habitats, both of which are known to have impoverished piscine predator regimes. Focal fishes that inhabited sulfidic springs showed slightly weaker avoidance reactions when presented with several naturally occurring predatory cichlids, but strongest differences to populations from non-sulfidic habitats were found in a decreased shoaling tendency with non-predatory swordtail (Xiphophorus hellerii females. When comparing avoidance reactions between P. mexicana from a sulfidic cave (Cueva del Azufre and the adjacent sulfidic surface creek (El Azufre, we found only slight differences in predator avoidance, but surface fish reacted much more strongly to the non-predatory cichlid Vieja bifasciata. Our third experiment was designed to disentangle learned from innate effects of predator recognition. We compared laboratory-reared (i.e., predator-naïve and wild-caught (i.e., predator-experienced individuals of P. mexicana from a non-sulfidic river and found no differences in their reaction towards the presented predators. Overall, our results indicate (1 that predator avoidance is still functional in extremophile Poecilia spp. and (2 that predator recognition and avoidance reactions have a strong genetic basis.

  7. Significant Changes in the Environment and in Teaching Methodology of an E-Learning Discipline to Avoid Dropouts in a Course at the Federal Institute

    Science.gov (United States)

    Oliveira, Gustavo Prado; Aarreniemi-Jokipelto, Päivi; Boaventura, Ricardo Soares

    2015-01-01

    The research is conducted in a public institute of education and technology to boost graduation especially with the help of an e-learning environment adopted. The Directory of E-learning Education from Federal Institute of Triangulo Mineiro coordinates all administrative and pedagogical aspects of 4,000 students registered in 11 e-learning…

  8. Avoidable mortality in Lithuania.

    OpenAIRE

    Gaizauskiene, A.; Gurevicius, R

    1995-01-01

    STUDY OBJECTIVE--The study aimed to analyse avoidable mortality in Lithuania as an index of the quality of health care and to assess trends in avoidable mortality from 1970-90. SETTING AND PARTICIPANTS--All deaths of Lithuanian residents aged between 0 and 64 years between 1970 and 1990 were analysed. MEASUREMENTS AND MAIN RESULTS--Twenty seven per cent of all deaths in this age group were avoidable. Avoidable deaths were grouped into preventable and treatable ones. Treatable causes of death ...

  9. Avoidant personality disorder

    Science.gov (United States)

    ... Names Personality disorder - avoidant References American Psychiatric Association. Diagnostic and statistical manual of mental disorders. 5th ed. Arlington, VA: American Psychiatric Publishing. 2013. ...

  10. Avoided by association: acquisition, extinction, and renewal of avoidance tendencies toward conditioned fear stimuli

    NARCIS (Netherlands)

    A.M. Krypotos; M. Effting; I. Arnaudova; M. Kindt; T. Beckers

    2013-01-01

    Traditional theoretical models hold that avoidance reflects the interplay of Pavlovian and instrumental learning. Here we suggest that avoidance tendencies to intrinsically neutral cues may be established by mere Pavlovian association. Following fear conditioning, in which pictures of one object wer

  11. Using Life-Cycle Human Factors Engineering to Avoid $2.4 Million in Costs: Lessons Learned from NASA's Requirements Verification Process for Space Payloads

    Science.gov (United States)

    Carr, Daniel; Ellenberger, Rich

    2008-01-01

    The Human Factors Implementation Team (HFIT) process has been used to verify human factors requirements for NASA International Space Station (ISS) payloads since 2003, resulting in $2.4 million in avoided costs. This cost benefit has been realized by greatly reducing the need to process time-consuming formal waivers (exceptions) for individual requirements violations. The HFIT team, which includes astronauts and their technical staff, acts as the single source for human factors requirements integration of payloads. HFIT has the authority to provide inputs during early design phases, thus eliminating many potential requirements violations in a cost-effective manner. In those instances where it is not economically or technically feasible to meet the precise metric of a given requirement, HFIT can work with the payload engineers to develop common sense solutions and formally document that the resulting payload design does not materially affect the astronaut s ability to operate and interact with the payload. The HFIT process is fully ISO 9000 compliant and works concurrently with NASA s formal systems engineering work flow. Due to its success with payloads, the HFIT process is being adapted and extended to ISS systems hardware. Key aspects of this process are also being considered for NASA's Space Shuttle replacement, the Crew Exploration Vehicle.

  12. Avoiding Computer Viruses.

    Science.gov (United States)

    Rowe, Joyce; And Others

    1989-01-01

    The threat of computer sabotage is a real concern to business teachers and others responsible for academic computer facilities. Teachers can minimize the possibility. Eight suggestions for avoiding computer viruses are given. (JOW)

  13. Gamma-butyrolactone (GBL) disruption of passive avoidance learning in the day-old chick appears to be due to its effect on GABAB not gamma-hydroxybutyric [corrected] acid (GHB) receptors.

    Science.gov (United States)

    Sherry, Joanne M; Hazi, Agnes; Hale, Mathew W; Milsome, Sarah L; Crowe, Simon F

    2009-02-11

    Gamma-butyrolactone (GBL) is a prodrug to gamma-hydroxybutyric acid (GHB) and metabolises to GHB when ingested. Discrimination stimulus studies report generalisation of effects of GHB to GBL. While amnesia is one of the most commonly reported symptoms of GHB's ingestion in human users, as yet few studies have examined this effect. Although an endogenous GHB specific receptor is present in the brain, several studies have indicated that the clinical effects of exogenous doses of GBL/GHB are due to its action on GABA(B) receptors rather than on the GHB receptor. In this series of studies, New Hampshire x White leghorn cockerels were trained using a modified version of the passive avoidance learning task. Subcutaneous injections of GBL induced a memory deficit by 10 min post-training, which persisted for at least 24 h. No effect on memory was seen with administration of the specific GHB agonist NCS-356 (gamma-p-chlorophenyl-trans-4-hydroxycrotonate). The GBL-induced memory deficit appeared similar to the deficit produced by baclofen, where the antagonist facilitated learning. Additionally, GBL-induced memory deficit was ameliorated by application of a GABA(B) antagonist. The results support the hypothesis that GBL exerts its influence on memory via the GABA(B) receptor rather than by the specific GHB receptor.

  14. Myelin Avoids the JAM.

    Science.gov (United States)

    Follis, Rose M; Carter, Bruce D

    2016-08-17

    In this issue of Neuron, Redmond et al. (2016) identify junction adhesion molecule 2 (JAM2) as an inhibitor of somatodendritic myelination in spinal cord neurons, thereby elucidating how myelin forms on axons but avoids dendrites and cell bodies. PMID:27537479

  15. Avoiding the Flu

    Science.gov (United States)

    ... of this page please turn Javascript on. Feature: Flu Avoiding the Flu Past Issues / Fall 2009 Table of Contents Children ... should still get the 2009 H1N1 vaccine. H1N1 Flu: Who Should Be Vaccinated First The Centers for ...

  16. The challenges for scientists in avoiding plagiarism.

    Science.gov (United States)

    Fisher, E R; Partin, K M

    2014-01-01

    Although it might seem to be a simple task for scientists to avoid plagiarism and thereby an allegation of research misconduct, assessment of trainees in the Responsible Conduct of Research and recent findings from the National Science Foundation Office of Inspector General regarding plagiarism suggests otherwise. Our experiences at a land-grant academic institution in assisting researchers in avoiding plagiarism are described. We provide evidence from a university-wide multi-disciplinary course that understanding how to avoid plagiarism in scientific writing is more difficult than it might appear, and that a failure to learn the rules of appropriate citation may cause dire consequences. We suggest that new strategies to provide training in avoiding plagiarism are required.

  17. The challenges for scientists in avoiding plagiarism.

    Science.gov (United States)

    Fisher, E R; Partin, K M

    2014-01-01

    Although it might seem to be a simple task for scientists to avoid plagiarism and thereby an allegation of research misconduct, assessment of trainees in the Responsible Conduct of Research and recent findings from the National Science Foundation Office of Inspector General regarding plagiarism suggests otherwise. Our experiences at a land-grant academic institution in assisting researchers in avoiding plagiarism are described. We provide evidence from a university-wide multi-disciplinary course that understanding how to avoid plagiarism in scientific writing is more difficult than it might appear, and that a failure to learn the rules of appropriate citation may cause dire consequences. We suggest that new strategies to provide training in avoiding plagiarism are required. PMID:24785995

  18. AVOIDING MANUSCRIPT MISTAKES

    OpenAIRE

    Grindstaff, Terry L.; Saliba, Susan A.

    2012-01-01

    Writing a scientific manuscript can be a consuming, but rewarding task with a number of intrinsic and extrinsic benefits. The ability to write a scientific manuscript is typically not an emphasized component of most entry‐level professional programs. The purpose of this overview is to provide authors with suggestions to improve manuscript quality and to provide mechanisms to avoid common manuscript mistakes that are often identified by journal reviewers and editors.

  19. Indonesia : Avoiding the Trap

    OpenAIRE

    World Bank

    2014-01-01

    Within the next two decades Indonesia aspires to generate prosperity, avoid a middle-income trap and leave no one behind as it tries to catch up with high-income economies. These are ambitious goals. Realizing them requires sustained high growth and job creation, as well as reduced inequality. Can Indonesia achieve them? This report argues that the country has the potential to rise and bec...

  20. Prion Disease: Learn the Facts. Avoid Exposure.

    Centers for Disease Control (CDC) Podcasts

    2011-05-23

    This podcast discusses prion diseases and the risk of exposure associated with some common activities.  Created: 5/23/2011 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 5/23/2011.

  1. Avoiding Neurological Pitfalls

    Science.gov (United States)

    Crossland, John

    2014-01-01

    In the past, teaching has suffered from applying tentative research from neuroscience directly to the classroom. Even though the last decade has seen a step change in efforts to bring together education and neuroscience research, the dialogue is still in its infancy. What do you do if you want to learn more? What does the research really tell us?…

  2. On partitions avoiding right crossings

    OpenAIRE

    Yan, Sherry H. F.; Xu, Yuexiao

    2011-01-01

    Recently, Chen et al. derived the generating function for partitions avoiding right nestings and posed the problem of finding the generating function for partitions avoiding right crossings. In this paper, we derive the generating function for partitions avoiding right crossings via an intermediate structure of partial matchings avoiding 2-right crossings and right nestings. We show that there is a bijection between partial matchings avoiding 2-right crossing and right nestings and partitions...

  3. Avoidable waste management costs

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, K.; Burns, M.; Priebe, S.; Robinson, P.

    1995-01-01

    This report describes the activity based costing method used to acquire variable (volume dependent or avoidable) waste management cost data for routine operations at Department of Energy (DOE) facilities. Waste volumes from environmental restoration, facility stabilization activities, and legacy waste were specifically excluded from this effort. A core team consisting of Idaho National Engineering Laboratory, Los Alamos National Laboratory, Rocky Flats Environmental Technology Site, and Oak Ridge Reservation developed and piloted the methodology, which can be used to determine avoidable waste management costs. The method developed to gather information was based on activity based costing, which is a common industrial engineering technique. Sites submitted separate flow diagrams that showed the progression of work from activity to activity for each waste type or treatability group. Each activity on a flow diagram was described in a narrative, which detailed the scope of the activity. Labor and material costs based on a unit quantity of waste being processed were then summed to generate a total cost for that flow diagram. Cross-complex values were calculated by determining a weighted average for each waste type or treatability group based on the volume generated. This study will provide DOE and contractors with a better understanding of waste management processes and their associated costs. Other potential benefits include providing cost data for sites to perform consistent cost/benefit analysis of waste minimization and pollution prevention (WMIN/PP) options identified during pollution prevention opportunity assessments and providing a means for prioritizing and allocating limited resources for WMIN/PP.

  4. Avoidable waste management costs

    International Nuclear Information System (INIS)

    This report describes the activity based costing method used to acquire variable (volume dependent or avoidable) waste management cost data for routine operations at Department of Energy (DOE) facilities. Waste volumes from environmental restoration, facility stabilization activities, and legacy waste were specifically excluded from this effort. A core team consisting of Idaho National Engineering Laboratory, Los Alamos National Laboratory, Rocky Flats Environmental Technology Site, and Oak Ridge Reservation developed and piloted the methodology, which can be used to determine avoidable waste management costs. The method developed to gather information was based on activity based costing, which is a common industrial engineering technique. Sites submitted separate flow diagrams that showed the progression of work from activity to activity for each waste type or treatability group. Each activity on a flow diagram was described in a narrative, which detailed the scope of the activity. Labor and material costs based on a unit quantity of waste being processed were then summed to generate a total cost for that flow diagram. Cross-complex values were calculated by determining a weighted average for each waste type or treatability group based on the volume generated. This study will provide DOE and contractors with a better understanding of waste management processes and their associated costs. Other potential benefits include providing cost data for sites to perform consistent cost/benefit analysis of waste minimization and pollution prevention (WMIN/PP) options identified during pollution prevention opportunity assessments and providing a means for prioritizing and allocating limited resources for WMIN/PP

  5. Communication Avoiding ILU0 Preconditioner

    OpenAIRE

    Grigori, Laura; Moufawad, Sophie

    2013-01-01

    In this paper we present a communication avoiding ILU0 preconditioner for solving large linear systems of equations by using iterative Krylov subspace methods. Recent research has focused on communication avoiding Krylov subspace methods based on so called s-step methods. However there is no communication avoiding preconditioner yet, and this represents a serious limitation of these methods. Our preconditioner allows to perform s iterations of the iterative method with no communication, throu...

  6. Stimulus conflict triggers behavioral avoidance.

    Science.gov (United States)

    Dignath, David; Eder, Andreas B

    2015-12-01

    According to a recent extension of the conflict-monitoring theory, conflict between two competing response tendencies is registered as an aversive event and triggers a motivation to avoid the source of conflict. In the present study, we tested this assumption. Over five experiments, we examined whether conflict is associated with an avoidance motivation and whether stimulus conflict or response conflict triggers an avoidance tendency. Participants first performed a color Stroop task. In a subsequent motivation test, participants responded to Stroop stimuli with approach- and avoidance-related lever movements. These results showed that Stroop-conflict stimuli increased the frequency of avoidance responses in a free-choice motivation test, and also increased the speed of avoidance relative to approach responses in a forced-choice test. High and low proportions of response conflict in the Stroop task had no effect on avoidance in the motivation test. Avoidance of conflict was, however, obtained even with new conflict stimuli that had not been presented before in a Stroop task, and when the Stroop task was replaced with an unrelated filler task. Taken together, these results suggest that stimulus conflict is sufficient to trigger avoidance.

  7. Acquaintance Rape: Effective Avoidance Strategies.

    Science.gov (United States)

    Levine-MacCombie, Joyce; Koss, Mary P.

    1986-01-01

    Determined that acknowledged and unacknowledged acquaintance rape victims and rape avoiders could be discriminated by situational variables and response strategies. Avoiders were less likely to have experienced passive or internalizing emotions at the time of the assault, perceived the assault as less violent, and were more likely to have utilized…

  8. Panic disorder and exercise avoidance

    Directory of Open Access Journals (Sweden)

    Ricardo W. Muotri

    2014-03-01

    Full Text Available Objectives: 1 To identify whether patients with panic disorder in general and those with the respiratory subtype in particular actively avoid exercise; 2 to investigate physiological differences in cardiopulmonary function parameters in patients with panic disorder in general, patients with the respiratory subtype of panic disorder, and healthy controls upon exercise challenge. Methods: Patients with panic disorder were classified as having either the respiratory or the non-respiratory subtype. Both groups were compared to controls in terms of exercise avoidance patterns and performance on cardiopulmonary exercise testing. Results: Patients with panic disorder exhibited higher exercise avoidance scores and worse performance on cardiopulmonary exercise testing as compared with controls. No differences were found between patients with the respiratory and non-respiratory subtypes. Conclusions: Exercise avoidance is present in panic disorder and is associated with poorer performance on cardiopulmonary exercise testing. These findings are not limited to patients with the respiratory subtype of the disorder.

  9. Neuromorphic UAS Collision Avoidance Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Using biologically-inspired neuromorphic optic flow algorithms is a novel approach in collision avoidance for UAS. Traditional computer vision algorithms rely on...

  10. Vision-based obstacle avoidance

    Science.gov (United States)

    Galbraith, John

    2006-07-18

    A method for allowing a robot to avoid objects along a programmed path: first, a field of view for an electronic imager of the robot is established along a path where the electronic imager obtains the object location information within the field of view; second, a population coded control signal is then derived from the object location information and is transmitted to the robot; finally, the robot then responds to the control signal and avoids the detected object.

  11. The developmental dynamics of task-avoidant behavior and math performance in kindergarten and elementary school

    OpenAIRE

    Hirvonen, Riikka; Tolvanen, Asko; Aunola, Kaisa; Nurmi, Jari-Erik

    2012-01-01

    Besides cognitive factors, children's learning at school may be influenced by more dynamic phenomena, such as motivation and achievement-related task-avoidant behavior. The present study examined the developmental dynamics of task-avoidant behavior and math performance from kindergarten to Grade 4. A total of 225 children were tested for their arithmetic skills in kindergarten and in Grades 1, 2, and 4 of elementary school. Children's task-avoidant behavior in learning situations was rated by...

  12. Avoiding Confusion between Predictors and Inhibitors in Value Function Approximation

    OpenAIRE

    Connor, Patrick C.; Trappenberg, Thomas P

    2013-01-01

    In reinforcement learning, the goal is to seek rewards and avoid punishments. A simple scalar captures the value of a state or of taking an action, where expected future rewards increase and punishments decrease this quantity. Naturally an agent should learn to predict this quantity to take beneficial actions, and many value function approximators exist for this purpose. In the present work, however, we show how value function approximators can cause confusion between predictors of an outcome...

  13. Levels of arginine-vasopressin in cerebrospinal fluid during passive avoidance behavior in rats

    OpenAIRE

    Kloet, E.R. de; Laczi, F.; Gaffori, O.; Fekete, M.; Wied, D. de

    1984-01-01

    The concentration of immunoreactive arginine-vasopressin (IR-AVP) was measured in the cerebrospinal fluid (CSF) during acquisition and retention of passive avoidance behavior. IR-AVP level in CSF of male Wistar rats immediately after the learning trial was increased; the rate of which was related to the intensity of the electric footschock during the learning trial and the avoidance latency as measured 1 day after the learning trial. Immediately after the 24 h retention test IR-AVP levels wer...

  14. Avoiding plagiarism in academic writing.

    Science.gov (United States)

    Anderson, Irene

    Plagiarism means taking the work of another and presenting it as one's own, resulting in potential upset for the original author and disrepute for the professions involved. This article aims to explore the issue of plagiarism and some mechanisms for detection and avoidance.

  15. Avoiding unfavourable outcomes in liposuction

    Directory of Open Access Journals (Sweden)

    Atul Khanna

    2013-01-01

    Full Text Available The origin of liposuction can be traced to an adverse event by Dujarrier in 1921 when he used a uterine curette to remove fat from the knees of a ballerina ending in an amputation secondary to damage of the femoral artery. The history of liposuction since then has been one of avoiding complications and optimising outcome. After this adverse event, liposuction was abandoned until the 1960′s when Schrudde revived the practice using small stab incisions and sharp curettage with the secondary suction to aspirate the freed tissue. This technique was associated with a high incidence of complications especially seroma and skin necrosis. Illouz then replaced the curette with a blunt cannula connected to vacuum pump thus avoiding the complications of a sharp curette. Despite the presence of various techniques for liposuction, suction assisted liposuction (SAL is still the standard technique of liposuction. This article aims to discuss literature regarding the various aspects of liposuction (SAL and to highlight the salient points in the literature and in the senior author′s experience in order to avoid unfavourable outcomes in liposuction. A literature review on avoiding complication is in liposuction including some of the seminal papers on liposuction. Liposuction is generally a safe procedure with reproducible outcome. Just like any surgical procedure it should be treated with the utmost care. Illouz published 10 commandments for liposuction in 1989 and we review these commandments to demonstrate how liposuction has evolved.

  16. Avoiding plagiarism in academic writing.

    Science.gov (United States)

    Anderson, Irene

    Plagiarism means taking the work of another and presenting it as one's own, resulting in potential upset for the original author and disrepute for the professions involved. This article aims to explore the issue of plagiarism and some mechanisms for detection and avoidance. PMID:19186631

  17. Plagiarism Avoidance in Academic Submissions

    OpenAIRE

    Cully, Philip

    2013-01-01

    The purpose of this paper is to provide undergraduate students with an introductory resource focusing on plagiarism avoidance. It sets out to identify often confusing associated nuances. From the perspective of paraphrasing, the requirements attaching to the necessary provision of proper citations are explored. The paper concludes by pondering the topic of reliability of sources.

  18. Avoidance: grammatical or semantic causes?

    NARCIS (Netherlands)

    J.H. Hulstijn; E. Marchena

    1989-01-01

    This article follows up on a study by Dagut and Laufer (1985), who found that Hebrew learners of English avoid phrasal verbs, such as ‘let down’, while preferring one-word verbs, such as ‘;disappoint’, since phrasal verbs do not exist in Hebrew. A corollary derived from Dagut and Laufer's study is t

  19. How to avoid exercise injuries

    Science.gov (United States)

    ... such as: Walking Swimming Riding a stationary bike Golf These types of exercise are less likely to ... good working condition Is used correctly and consistently Learn Good Form If you are new to an ...

  20. Obstacle Avoidance Through Visual Teleoperation

    Directory of Open Access Journals (Sweden)

    Muhammad Usman Keerio

    2009-01-01

    Full Text Available This paper presents a novel controlling approach forHumanoid Robot to work safely in critical situations like badlight environment using Visual Teleoperation. In this regardmodeling environments for Humanoid Teleoperation Systemis developed. Here virtual reality modeling environmentincludes development of virtual Humanoid BHR-2, andvirtual objects like table etc. The main goal of this work is toenhance our visual teleoperation system for BHR-2 in orderto avoid any collision during real time operation. SoftwareMaya is used for modeling and simulations. Maya plug-insin VC++ provides efficient modeling rule, real timeinteraction, and time saving rendering approach in a virtualenvironment. In this paper the validity of proposed scheme isshown by conducting experiments using offline step overtrajectory to avoid obstacle in bad light environment.

  1. Jam avoidance with autonomous systems

    OpenAIRE

    Tordeux, Antoine; Lassarre, Sylvain

    2015-01-01

    Many car-following models are developed for jam avoidance in highways. Two mechanisms are used to improve the stability: feedback control with autonomous models and increasing of the interaction within cooperative ones. In this paper, we compare the linear autonomous and collective optimal velocity (OV) models. We observe that the stability is significantly increased by adding predecessors in interaction with collective models. Yet autonomous and collective approaches are close when the speed...

  2. Consumer Privacy and Marketing Avoidance

    OpenAIRE

    Il-Horn Hann; Kai-Lung Hui; Sang-Yong Tom Lee; Ivan Png

    2005-01-01

    We introduce consumer avoidance into analytical marketing research. We show that consumer efforts to conceal themselves and to deflect marketing have a crucial impact on sellers¡¯ marketing strategy. Under reasonable conditions, seller marketing is a strategic complement with consumer concealment. Hence, consumer measures to conceal themselves from marketing will increase its cost-effectiveness and lead sellers to market more. Policies that encourage consumers to conceal their identities woul...

  3. Avoiding congestion in recommender systems

    International Nuclear Information System (INIS)

    Recommender systems use the historical activities and personal profiles of users to uncover their preferences and recommend objects. Most of the previous methods are based on objects’ (and/or users’) similarity rather than on their difference. Such approaches are subject to a high risk of increasingly exposing users to a narrowing band of popular objects. As a result, a few objects may be recommended to an enormous number of users, resulting in the problem of recommendation congestion, which is to be avoided, especially when the recommended objects are limited resources. In order to quantitatively measure a recommendation algorithm's ability to avoid congestion, we proposed a new metric inspired by the Gini index, which is used to measure the inequality of the individual wealth distribution in an economy. Besides this, a new recommendation method called directed weighted conduction (DWC) was developed by considering the heat conduction process on a user–object bipartite network with different thermal conductivities. Experimental results obtained for three benchmark data sets showed that the DWC algorithm can effectively avoid system congestion, and greatly improve the novelty and diversity, while retaining relatively high accuracy, in comparison with the state-of-the-art methods. (paper)

  4. ITI-signals and prelimbic cortex facilitate avoidance acquisition and reduce avoidance latencies, respectively, in male WKY rats

    Directory of Open Access Journals (Sweden)

    Kevin D Beck

    2014-11-01

    Full Text Available As a model of anxiety disorder vulnerability, male Wistar-Kyoto (WKY rats acquire lever-press avoidance behavior more readily than outbred Sprague Dawley rats, and their acquisition is enhanced by the presence of a discrete signal presented during the inter-trial intervals (ITIs, suggesting it is perceived as a safety signal. A series of experiments were conducted to determine if this is the case. Additional experiments investigated if the avoidance facilitation relies upon processing through medial prefrontal cortex (mPFC. The results suggest that the ITI-signal facilitates acquisition during the early stages of the avoidance acquisition process, when the rats are initially acquiring escape behavior and then transitioning to avoidance behavior. Post-avoidance introduction of the visual ITI-signal into other associative learning tasks failed to confirm that the visual stimulus had acquired the properties of a conditioned inhibitor. Shortening the signal from the entirety of the 3 min ITI to only the first 5 s of the 3 min ITI slowed acquisition during the first 4 sessions, suggesting the flashing light is not functioning as a feedback signal. The prelimbic (PL cortex showed greater activation during the period of training when the transition from escape responding to avoidance responding occurs. Only combined PL+infralimbic cortex lesions modestly slowed avoidance acquisition, but PL cortex lesions slowed avoidance response latencies. Thus, the flashing light ITI-signal is not likely perceived as a safety signal nor is it serving as a feedback signal. The functional role of the PL cortex appears to be to increase the drive towards responding to the threat of the warning signal. Hence, avoidance susceptibility displayed by male WKY rats may be driven, in part, both by external stimuli (ITI signal as well as by enhanced threat recognition to the warning signal via the PL cortex.

  5. Jam avoidance with autonomous systems

    CERN Document Server

    Tordeux, Antoine

    2016-01-01

    Many car-following models are developed for jam avoidance in highways. Two mechanisms are used to improve the stability: feedback control with autonomous models and increasing of the interaction within cooperative ones. In this paper, we compare the linear autonomous and collective optimal velocity (OV) models. We observe that the stability is significantly increased by adding predecessors in interaction with collective models. Yet autonomous and collective approaches are close when the speed difference term is taking into account. Within the linear OV models tested, the autonomous models including speed difference are sufficient to maximise the stability.

  6. Avoiding unfavourable outcomes in liposuction

    OpenAIRE

    Atul Khanna; George Filobbos

    2013-01-01

    The origin of liposuction can be traced to an adverse event by Dujarrier in 1921 when he used a uterine curette to remove fat from the knees of a ballerina ending in an amputation secondary to damage of the femoral artery. The history of liposuction since then has been one of avoiding complications and optimising outcome. After this adverse event, liposuction was abandoned until the 1960′s when Schrudde revived the practice using small stab incisions and sharp curettage with the secondary suc...

  7. Traveler's Health: Avoid Bug Bites

    Science.gov (United States)

    ... Guide Learn About Destination See a Doctor Pre-Travel Appointment Your Health Status How Diseases Spread Pack Smart Plan Ahead ... During Trip After Your Trip CDC-TV Videos Travel to the Olympics ... Presentations for Health Professionals Yellow Fever Vaccine Course About the Yellow ...

  8. Learning

    Directory of Open Access Journals (Sweden)

    Mohsen Laabidi

    2014-01-01

    Full Text Available Nowadays learning technologies transformed educational systems with impressive progress of Information and Communication Technologies (ICT. Furthermore, when these technologies are available, affordable and accessible, they represent more than a transformation for people with disabilities. They represent real opportunities with access to an inclusive education and help to overcome the obstacles they met in classical educational systems. In this paper, we will cover basic concepts of e-accessibility, universal design and assistive technologies, with a special focus on accessible e-learning systems. Then, we will present recent research works conducted in our research Laboratory LaTICE toward the development of an accessible online learning environment for persons with disabilities from the design and specification step to the implementation. We will present, in particular, the accessible version “MoodleAcc+” of the well known e-learning platform Moodle as well as new elaborated generic models and a range of tools for authoring and evaluating accessible educational content.

  9. Obstacle-avoiding navigation system

    Science.gov (United States)

    Borenstein, Johann; Koren, Yoram; Levine, Simon P.

    1991-01-01

    A system for guiding an autonomous or semi-autonomous vehicle through a field of operation having obstacles thereon to be avoided employs a memory for containing data which defines an array of grid cells which correspond to respective subfields in the field of operation of the vehicle. Each grid cell in the memory contains a value which is indicative of the likelihood, or probability, that an obstacle is present in the respectively associated subfield. The values in the grid cells are incremented individually in response to each scan of the subfields, and precomputation and use of a look-up table avoids complex trigonometric functions. A further array of grid cells is fixed with respect to the vehicle form a conceptual active window which overlies the incremented grid cells. Thus, when the cells in the active window overly grid cell having values which are indicative of the presence of obstacles, the value therein is used as a multiplier of the precomputed vectorial values. The resulting plurality of vectorial values are summed vectorially in one embodiment of the invention to produce a virtual composite repulsive vector which is then summed vectorially with a target-directed vector for producing a resultant vector for guiding the vehicle. In an alternative embodiment, a plurality of vectors surrounding the vehicle are computed, each having a value corresponding to obstacle density. In such an embodiment, target location information is used to select between alternative directions of travel having low associated obstacle densities.

  10. Adaptive avoidance of reef noise.

    Directory of Open Access Journals (Sweden)

    Stephen D Simpson

    Full Text Available Auditory information is widely used throughout the animal kingdom in both terrestrial and aquatic environments. Some marine species are dependent on reefs for adult survival and reproduction, and are known to use reef noise to guide orientation towards suitable habitat. Many others that forage in food-rich inshore waters would, however, benefit from avoiding the high density of predators resident on reefs, but nothing is known about whether acoustic cues are used in this context. By analysing a sample of nearly 700,000 crustaceans, caught during experimental playbacks in light traps in the Great Barrier Reef lagoon, we demonstrate an auditory capability in a broad suite of previously neglected taxa, and provide the first evidence in any marine organisms that reef noise can act as a deterrent. In contrast to the larvae of species that require reef habitat for future success, which showed an attraction to broadcasted reef noise, taxa with a pelagic or nocturnally emergent lifestyle actively avoided it. Our results suggest that a far greater range of invertebrate taxa than previously thought can respond to acoustic cues, emphasising yet further the potential negative impact of globally increasing levels of underwater anthropogenic noise.

  11. [Alteration of neural oscillations in hippocampal CA3 area in the fast avoidance response rat before and after electric shock avoidance training].

    Science.gov (United States)

    Wang, Wei-Wei; Wang, Dan-Dan; Wang, Dan; Guan, Yan; Tang, Ying-Ying; Ye, Zheng; Li, Jing; Li, Min; Zhu, Zai-Man; Pan, Qun-Wan

    2015-10-25

    The purpose of the present study is to explore the relationship of spatial learning ability and specific electrical activities of neural oscillations in the rat. The fast and general avoidance response groups were selected on the basis of the animals' responses to the electric shock in Y type maze, and their local field potentials (LFPs) of hippocampal CA3 area were recorded by wireless telemetry before and after shock avoidance training, respectively. The components of neural oscillations related to spatial identifying and learning ability were analyzed. The results showed that, compared with the general avoidance response group, the fast avoidance response group did not show any differences of LFPs in hippocampal CA3 area before electric shock avoidance trial, but showed significantly increased percentages of 0-10 Hz and 30-40 Hz rhythm in right hippocampal CA3 area after the shock avoidance training (P avoidance response rats after training, while the θ rhythm percentage remained unchanged. In contrast, θ rhythm percentage and the large amplitude (intensity: +2.5 - -2.5 db) θ waves in right CA3 area of general avoidance response rats were significantly reduced after training (P avoidance response rats.

  12. Avoiding Braess' Paradox Through Collective Intelligence

    Science.gov (United States)

    Wolpert , David H.; Tumer, Kagan

    1999-01-01

    In an Ideal Shortest Path Algorithm (ISPA), at each moment each router in a network sends all of its traffic down the path that will incur the lowest cost to that traffic. In the limit of an infinitesimally small amount of traffic for a particular router, its routing that traffic via an ISPA is optimal, as far as cost incurred by that traffic is concerned. We demonstrate though that in many cases, due to the side-effects of one router's actions on another routers performance, having routers use ISPA's is suboptimal as far as global aggregate cost is concerned, even when only used to route infinitesimally small amounts of traffic. As a particular example of this we present an instance of Braess' paradox for ISPA'S, in which adding new links to a network decreases overall throughput. We also demonstrate that load-balancing, in which the routing decisions are made to optimize the global cost incurred by all traffic currently being routed, is suboptimal as far as global cost averaged across time is concerned. This is also due to "side-effects", in this case of current routing decision on future traffic. The theory of COllective INtelligence (COIN) is concerned precisely with the issue of avoiding such deleterious side-effects. We present key concepts from that theory and use them to derive an idealized algorithm whose performance is better than that of the ISPA, even in the infinitesimal limit. We present experiments verifying this, and also showing that a machine-learning-based version of this COIN algorithm in which costs are only imprecisely estimated (a version potentially applicable in the real world) also outperforms the ISPA, despite having access to less information than does the ISPA. In particular, this COIN algorithm avoids Braess' paradox.

  13. Optimizing Sampling Design to Deal with Mist-Net Avoidance in Amazonian Birds and Bats

    OpenAIRE

    João Tiago Marques; Ramos Pereira, Maria J.; Marques, Tiago A.; Carlos David Santos; Joana Santana; Pedro Beja; Palmeirim, Jorge M.

    2013-01-01

    Mist netting is a widely used technique to sample bird and bat assemblages. However, captures often decline with time because animals learn and avoid the locations of nets. This avoidance or net shyness can substantially decrease sampling efficiency. We quantified the day-to-day decline in captures of Amazonian birds and bats with mist nets set at the same location for four consecutive days. We also evaluated how net avoidance influences the efficiency of surveys under different logistic scen...

  14. The Role of Informative and Ambiguous Feedback in Avoidance Behavior: Empirical and Computational Findings

    OpenAIRE

    Ahmed A. Moustafa; Jony Sheynin; Myers, Catherine E.

    2015-01-01

    Avoidance behavior is a critical component of many psychiatric disorders, and as such, it is important to understand how avoidance behavior arises, and whether it can be modified. In this study, we used empirical and computational methods to assess the role of informational feedback and ambiguous outcome in avoidance behavior. We adapted a computer-based probabilistic classification learning task, which includes positive, negative and no-feedback outcomes; the latter outcome is ambiguous as i...

  15. Evidence that conditioned avoidance responses are reinforced by positive prediction errors signaled by tonic striatal dopamine.

    Science.gov (United States)

    Dombrowski, Patricia A; Maia, Tiago V; Boschen, Suelen L; Bortolanza, Mariza; Wendler, Etieli; Schwarting, Rainer K W; Brandão, Marcus Lira; Winn, Philip; Blaha, Charles D; Da Cunha, Claudio

    2013-03-15

    We conducted an experiment in which hedonia, salience and prediction error hypotheses predicted different patterns of dopamine (DA) release in the striatum during learning of conditioned avoidance responses (CARs). The data strongly favor the latter hypothesis. It predicts that during learning of the 2-way active avoidance CAR task, positive prediction errors generated when rats do not receive an anticipated footshock (which is better than expected) cause DA release that reinforces the instrumental avoidance action. In vivo microdialysis in the rat striatum showed that extracellular DA concentration increased during early CAR learning and decreased throughout training returning to baseline once the response was well learned. In addition, avoidance learning was proportional to the degree of DA release. Critically, exposure of rats to the same stimuli but in an unpredictable, unavoidable, and inescapable manner, did not produce alterations from baseline DA levels as predicted by the prediction error but not hedonic or salience hypotheses. In addition, rats with a partial lesion of substantia nigra DA neurons, which did not show increased DA levels during learning, failed to learn this task. These data represent clear and unambiguous evidence that it was the factor positive prediction error, and not hedonia or salience, which caused increase in the tonic level of striatal DA and which reinforced learning of the instrumental avoidance response. PMID:22771418

  16. A neuro-collision avoidance strategy for robot manipulators

    Science.gov (United States)

    Onema, Joel P.; Maclaunchlan, Robert A.

    1992-01-01

    The area of collision avoidance and path planning in robotics has received much attention in the research community. Our study centers on a combination of an artificial neural network paradigm with a motion planning strategy that insures safe motion of the Articulated Two-Link Arm with Scissor Hand System relative to an object. Whenever an obstacle is encountered, the arm attempts to slide along the obstacle surface, thereby avoiding collision by means of the local tangent strategy and its artificial neural network implementation. This combination compensates the inverse kinematics of a robot manipulator. Simulation results indicate that a neuro-collision avoidance strategy can be achieved by means of a learning local tangent method.

  17. Predictive Potential Field-Based Collision Avoidance for Multicopters

    Science.gov (United States)

    Nieuwenhuisen, M.; Schadler, M.; Behnke, S.

    2013-08-01

    Reliable obstacle avoidance is a key to navigating with UAVs in the close vicinity of static and dynamic obstacles. Wheel-based mobile robots are often equipped with 2D or 3D laser range finders that cover the 2D workspace sufficiently accurate and at a high rate. Micro UAV platforms operate in a 3D environment, but the restricted payload prohibits the use of fast state-of-the-art 3D sensors. Thus, perception of small obstacles is often only possible in the vicinity of the UAV and a fast collision avoidance system is necessary. We propose a reactive collision avoidance system based on artificial potential fields, that takes the special dynamics of UAVs into account by predicting the influence of obstacles on the estimated trajectory in the near future using a learned motion model. Experimental evaluation shows that the prediction leads to smoother trajectories and allows to navigate collision-free through passageways.

  18. Learning

    OpenAIRE

    Mohsen Laabidi; Mohamed Jemni; Leila Jemni Ben Ayed; Hejer Ben Brahim; Amal Ben Jemaa

    2014-01-01

    Nowadays learning technologies transformed educational systems with impressive progress of Information and Communication Technologies (ICT). Furthermore, when these technologies are available, affordable and accessible, they represent more than a transformation for people with disabilities. They represent real opportunities with access to an inclusive education and help to overcome the obstacles they met in classical educational systems. In this paper, we will cover basic concepts of e-access...

  19. The Developmental Dynamics of Task-Avoidant Behavior and Math Performance in Kindergarten and Elementary School

    Science.gov (United States)

    Hirvonen, Riikka; Tolvanen, Asko; Aunola, Kaisa; Nurmi, Jari-Erik

    2012-01-01

    Besides cognitive factors, children's learning at school may be influenced by more dynamic phenomena, such as motivation and achievement-related task-avoidant behavior. The present study examined the developmental dynamics of task-avoidant behavior and math performance from kindergarten to Grade 4. A total of 225 children were tested for their…

  20. Graduated Exposure and Positive Reinforcement to Overcome Setting and Activity Avoidance in an Adolescent with Autism

    Science.gov (United States)

    Schmidt, Jonathan D.; Luiselli, James K.; Rue, Hanna; Whalley, Katherine

    2013-01-01

    Some students who have developmental disabilities avoid settings and activities that can improve their learning and quality of life. This two-phase study concerned an adolescent boy with autism who avoided the gross-motor exercise room, gymnasium, and music room at his school; he demonstrated distress, agitation, and problem behaviors when…

  1. Genetic Contributions to Avoidance-Based Decisions: Striatal D2 receptor Polymorphisms

    OpenAIRE

    Frank, Michael J.; Hutchison, Kent

    2009-01-01

    Individuals differ in their tendencies to seek positive decision outcomes or to avoid negative ones. At the neurobiological level, our model suggests that phasic changes in dopamine support learning to reinforce good decisions via striatal D1 receptors, and to avoid maladaptive choices via striatal D2 receptors. Accordingly, in a previous study individual differences in positive and negative learning were strongly modulated by two genetic polymorphisms factors related to striatal D1 and D2 fu...

  2. Effects of emotional reactivity on inhibitory avoidance in the elevated T-maze

    Directory of Open Access Journals (Sweden)

    C. Conde

    2000-02-01

    Full Text Available The possibility of the presence of inter-individual emotional differences and the memory performance of rats was examined in the elevated T-maze. Two kinds of aversively motivated behaviors, inhibitory avoidance and escape learning, were measured. Based on the number of trials to achieve a learning criterion, rats were divided into two subgroups with either low or high avoidance reactivity (LAR or HAR, respectively. Retention test avoidance latencies showed that HAR animals had better avoidance memory (Mann-Whitney rank sum test, P = 0.0035. No such differences were found for the escape component of this test. These data suggest that individual emotional differences affect inhibitory avoidance performance, which may help to explain the dispersion of the data observed in other studies using this paradigm.

  3. Disgust as an adaptive system for disease avoidance behaviour.

    Science.gov (United States)

    Curtis, Valerie; de Barra, Mícheál; Aunger, Robert

    2011-02-12

    Disgust is an evolved psychological system for protecting organisms from infection through disease avoidant behaviour. This 'behavioural immune system', present in a diverse array of species, exhibits universal features that orchestrate hygienic behaviour in response to cues of risk of contact with pathogens. However, disgust is also a dynamic adaptive system. Individuals show variation in pathogen avoidance associated with psychological traits like having a neurotic personality, as well as a consequence of being in certain physiological states such as pregnancy or infancy. Three specialized learning mechanisms modify the disgust response: the Garcia effect, evaluative conditioning and the law of contagion. Hygiene behaviour is influenced at the group level through social learning heuristics such as 'copy the frequent'. Finally, group hygiene is extended symbolically to cultural rules about purity and pollution, which create social separations and are enforced as manners. Cooperative hygiene endeavours such as sanitation also reduce pathogen prevalence. Our model allows us to integrate perspectives from psychology, ecology and cultural evolution with those of epidemiology and anthropology. Understanding the nature of disease avoidance psychology at all levels of human organization can inform the design of programmes to improve public health. PMID:21199843

  4. The Role of Informative and Ambiguous Feedback in Avoidance Behavior: Empirical and Computational Findings.

    Directory of Open Access Journals (Sweden)

    Ahmed A Moustafa

    Full Text Available Avoidance behavior is a critical component of many psychiatric disorders, and as such, it is important to understand how avoidance behavior arises, and whether it can be modified. In this study, we used empirical and computational methods to assess the role of informational feedback and ambiguous outcome in avoidance behavior. We adapted a computer-based probabilistic classification learning task, which includes positive, negative and no-feedback outcomes; the latter outcome is ambiguous as it might signal either a successful outcome (missed punishment or a failure (missed reward. Prior work with this task suggested that most healthy subjects viewed the no-feedback outcome as strongly positive. Interestingly, in a later version of the classification task, when healthy subjects were allowed to opt out of (i.e. avoid responding, some subjects ("avoiders" reliably avoided trials where there was a risk of punishment, but other subjects ("non-avoiders" never made any avoidance responses at all. One possible interpretation is that the "non-avoiders" valued the no-feedback outcome so positively on punishment-based trials that they had little incentive to avoid. Another possible interpretation is that the outcome of an avoided trial is unspecified and that lack of information is aversive, decreasing subjects' tendency to avoid. To examine these ideas, we here tested healthy young adults on versions of the task where avoidance responses either did or did not generate informational feedback about the optimal response. Results showed that provision of informational feedback decreased avoidance responses and also decreased categorization performance, without significantly affecting the percentage of subjects classified as "avoiders." To better understand these results, we used a modified Q-learning model to fit individual subject data. Simulation results suggest that subjects in the feedback condition adjusted their behavior faster following better

  5. Safety training: the elimination of avoidance-motivated aggression in dogs.

    Science.gov (United States)

    Tortora, D F

    1983-06-01

    This study sought to identify the behavioral characteristics and appropriate treatment of a form of instrumental aggression in companion dogs, herein recognized as avoidance-motivated aggression. In Experiment 1, retrospective data on 92 cases of dangerously aggressive dogs demonstrated the avoidance nature of the aggressive response and its intractability to established counterconditioning treatments. In Experiment 2, safety training, a modified avoidance-learning procedure, resulted in complete and permanent elimination of aggression in all of the 36 dogs tested. In addition, it produced extremely extinction-resistant prosocial avoidance responses, significant increases in the dogs' emotional stability, an avoidance-learning and safety acquisition response set, and improvements in measures of the dog's "carriage." Experiment 3 showed how effective safety training is when compared with other behavior modification techniques that, in theory, should have an impact on avoidance-motivated aggression. Experiment 4 demonstrated the critical importance of using the conditioned safety cue as a positive reinforcement. The relationship of avoidance-motivated aggression to other forms of aggression is discussed. The success of safety training compared with the failure of electrical aversion therapy is analyzed. The theoretical concepts of behavioral balance and an avoidance-learning set are presented. Suggestions to improve the effectiveness of counterconditioning for human avoidance-motivated pathologies are offered. All in all, the data seem to suggest that safety training may create in dogs a sense of control over environmental stressors. By teaching the dogs a behaviorally balanced battery of prosocial "coping" responses, they may be developing the canine counterpart of "self-efficacy" or "courage." It is suggested that this cognitive modification may provide the antithesis of "learned helplessness" and may be of prime importance to the success and stability of the

  6. Strategic Avoidance: Can Universities Learn from Other Sectors?

    Science.gov (United States)

    Kerr, Greg; Hosie, Peter

    2013-01-01

    Universities live in interesting times. For instance, government policies in Australia are allowing for more deregulation of the student market while overseas universities are entering the Australian domestic market. In an environment of increasing uncertainty, sound strategic planning is important. Processes including benchmarking, environmental…

  7. Low-Cost Avoidance Behaviors Are Resistant To Fear Extinction In Humans

    Directory of Open Access Journals (Sweden)

    Bram eVervliet

    2015-12-01

    Full Text Available Elevated levels of fear and avoidance are core symptoms across the anxiety disorders. It has long been known that fear serves to motivate avoidance. Consequently, fear extinction has been the primary focus in pre-clinical anxiety research for decades, under the implicit assumption that removing the motivator of avoidance (fear would automatically mitigate the avoidance behaviors as well. Although this assumption has intuitive appeal, it has received little scientific scrutiny. The scarce evidence from animal studies is mixed, while the assumption remains untested in humans. The current study applied an avoidance conditioning protocol in humans to investigate the effects of fear extinction on the persistence of low-cost avoidance. Online danger-safety ratings and skin conductance responses documented the dynamics of conditioned fear across avoidance and extinction phases. Anxiety- and avoidance-related questionnaires explored individual differences in rates of avoidance. Participants first learned to click a button during a predictive danger signal, in order to cancel an upcoming aversive electrical shock (avoidance conditioning. Next, fear extinction was induced by presenting the signal in the absence of shocks while button-clicks were prevented (by removing the button in Experiment 1, or by instructing not to click the button in Experiment 2. Most importantly, post-extinction availaibility of the button caused a significant return of avoidant button-clicks. In addition, trait-anxiety levels correlated positively with rates of avoidance during a predictive safety signal, and with the rate of pre- to post-extinction decrease during this signal. Fear measures gradually decreased during avoidance conditioning, as participants learned that button-clicks effectively canceled the shock. Preventing button-clicks elicited a sharp increase in fear, which subsequently extinguished. Fear remained low during avoidance testing, but danger-safety ratings

  8. Low-Cost Avoidance Behaviors are Resistant to Fear Extinction in Humans.

    Science.gov (United States)

    Vervliet, Bram; Indekeu, Ellen

    2015-01-01

    Elevated levels of fear and avoidance are core symptoms across the anxiety disorders. It has long been known that fear serves to motivate avoidance. Consequently, fear extinction has been the primary focus in pre-clinical anxiety research for decades, under the implicit assumption that removing the motivator of avoidance (fear) would automatically mitigate the avoidance behaviors as well. Although this assumption has intuitive appeal, it has received little scientific scrutiny. The scarce evidence from animal studies is mixed, while the assumption remains untested in humans. The current study applied an avoidance conditioning protocol in humans to investigate the effects of fear extinction on the persistence of low-cost avoidance. Online danger-safety ratings and skin conductance responses documented the dynamics of conditioned fear across avoidance and extinction phases. Anxiety- and avoidance-related questionnaires explored individual differences in rates of avoidance. Participants first learned to click a button during a predictive danger signal, in order to cancel an upcoming aversive electrical shock (avoidance conditioning). Next, fear extinction was induced by presenting the signal in the absence of shocks while button-clicks were prevented (by removing the button in Experiment 1, or by instructing not to click the button in Experiment 2). Most importantly, post-extinction availability of the button caused a significant return of avoidant button-clicks. In addition, trait-anxiety levels correlated positively with rates of avoidance during a predictive safety signal, and with the rate of pre- to post-extinction decrease during this signal. Fear measures gradually decreased during avoidance conditioning, as participants learned that button-clicks effectively canceled the shock. Preventing button-clicks elicited a sharp increase in fear, which subsequently extinguished. Fear remained low during avoidance testing, but danger-safety ratings increased again when

  9. Low-Cost Avoidance Behaviors are Resistant to Fear Extinction in Humans.

    Science.gov (United States)

    Vervliet, Bram; Indekeu, Ellen

    2015-01-01

    Elevated levels of fear and avoidance are core symptoms across the anxiety disorders. It has long been known that fear serves to motivate avoidance. Consequently, fear extinction has been the primary focus in pre-clinical anxiety research for decades, under the implicit assumption that removing the motivator of avoidance (fear) would automatically mitigate the avoidance behaviors as well. Although this assumption has intuitive appeal, it has received little scientific scrutiny. The scarce evidence from animal studies is mixed, while the assumption remains untested in humans. The current study applied an avoidance conditioning protocol in humans to investigate the effects of fear extinction on the persistence of low-cost avoidance. Online danger-safety ratings and skin conductance responses documented the dynamics of conditioned fear across avoidance and extinction phases. Anxiety- and avoidance-related questionnaires explored individual differences in rates of avoidance. Participants first learned to click a button during a predictive danger signal, in order to cancel an upcoming aversive electrical shock (avoidance conditioning). Next, fear extinction was induced by presenting the signal in the absence of shocks while button-clicks were prevented (by removing the button in Experiment 1, or by instructing not to click the button in Experiment 2). Most importantly, post-extinction availability of the button caused a significant return of avoidant button-clicks. In addition, trait-anxiety levels correlated positively with rates of avoidance during a predictive safety signal, and with the rate of pre- to post-extinction decrease during this signal. Fear measures gradually decreased during avoidance conditioning, as participants learned that button-clicks effectively canceled the shock. Preventing button-clicks elicited a sharp increase in fear, which subsequently extinguished. Fear remained low during avoidance testing, but danger-safety ratings increased again when

  10. 47 CFR 74.604 - Interference avoidance.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Interference avoidance. 74.604 Section 74.604 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES EXPERIMENTAL RADIO... Stations § 74.604 Interference avoidance. (a) (b) Where two or more licensees are assigned a common...

  11. AVOID BECOMING A VICTIM OF COUNTERFEIT ITEMS

    Energy Technology Data Exchange (ETDEWEB)

    WARRINER RD

    2011-07-13

    In today's globalized economy, we cannot live without imported products. Most people do not realize how thin the safety net of regulation and inspection really is. Less than three percent of imported products receive any form of government inspection prior to sale. Avoid flea markets, street vendors and deep discount stores. The sellers of counterfeit wares know where to market their products. They look for individuals who are hungry for a brand name item but do not want to pay a brand name price for it. The internet provides anonymity to the sellers of counterfeit products. Unlike Europe, U.S. law does not hold internet-marketing organizations, responsible for the quality of the products sold on their websites. These organizations will remove an individual vendor when a sufficient number of complaints are lodged, but they will not take responsibility for the counterfeit products you may have purchased. EBay has a number of counterfeit product guides to help you avoid being a victim of the sellers of these products. Ten percent of all medications taken worldwide are counterfeit. If you do buy medications on-line, be sure that the National Association of Boards of Pharmacy Verified Internet Pharmacy Practice Sites (VIPPS) recommends the pharmacy you choose to use. Inspect all medication purchases and report any change in color, shape, imprinting or odor to your pharmacist. If you take generic medications these attributes may change from one manufacturer to another. Your pharmacist should inform you of any changes when you refill your prescription. If they do not, get clarification prior to taking the medication. Please note that the Federal Drug Administration (FDA) does not regulate supplements. The FDA only steps in when a specific supplement proves to cause physical harm or contains a regulated ingredient. Due to counterfeiting, Underwriters Laboratories (UL) changed their label design three times since 1996. The new gold label should be attached to the cord

  12. Conditioned Flavor Aversion: A Mechanism for Goats to Avoid Condensed Tannins in Blackbrush

    OpenAIRE

    Provenza, Frederick D; Burritt, Elizabeth A; Clausen, T. P.; Bryant, J. P.; Reichardt, P. B.; Distel, Roberto A.

    1990-01-01

    It has been hypothesized that herbivores instinctively avoid tannin-containing plant parts in response to the adverse effects of tannins on forage digestion. However, we found that goats learned to avoid condensed tannins (CTs) from blackbrush current season's growth by associating the flavor of foods containing CTs with aversive postingestive consequences. The aversive consequences experienced by goats apparently are not related to digestion inhibition and may depend on the structure ...

  13. Signaled avoidance in the eye withdrawal reflex of the green crab

    OpenAIRE

    Abramson, Charles I.; ARMSTRONG, PHILIP M.; Feinman, Robin A.; Feinman, Richard D.

    1988-01-01

    Learning in a signaled avoidance procedure was studied in the eye withdrawal reflex of the green crab, Carcinus maenas. A puff of air to the eye, which causes eye retraction, was used as the unconditioned stimulus (US). A mild vibration on the carapace, which has no effect on untrained animals, was used as a warning (conditioned) stimulus (CS). Eye withdrawal during the CS led to the omission of the otherwise scheduled US. Acquisition was rapid, reaching about 75% avoidance after 30 trials. E...

  14. Failure of α-MSH to delay extinction of conditioned avoidance behavior in rats with lesions in the parafascicular nuclei of the thalamus

    NARCIS (Netherlands)

    Bohus, B.; Wied, D. de

    1967-01-01

    Bilateral lesions in the thalamic parafascicular area facilitate the rate of extinction of a conditioned avoidance response without affecting avoidance learning. Treatment with long-acting α-MSH during extinction failed to affect the rate of extinction of the avoidance response. Since this peptide d

  15. Conjecture on Avoidance of Big Crunch

    Institute of Scientific and Technical Information of China (English)

    SUN Cheng-Yi; ZHANG De-Hai

    2006-01-01

    By conjecturing the physics at the Planck scale, we modify the definition of the Hawking temperature and modify the Friedmann equation. It is found that we can avoid the singularity of the big crunch and obtain a bouncing cosmological model.

  16. Avoidant/Restrictive Food Intake Disorder

    Science.gov (United States)

    ... Intake Disorder Binge Eating Disorder Bulimia Nervosa Pica Rumination Disorder Avoidant/restrictive food intake disorder is characterized ... Intake Disorder Binge Eating Disorder Bulimia Nervosa Pica Rumination Disorder NOTE: This is the Consumer Version. CONSUMERS: ...

  17. Avoiding Anemia: Boost Your Red Blood Cells

    Science.gov (United States)

    ... link, please review our exit disclaimer . Subscribe Avoiding Anemia Boost Your Red Blood Cells If you’re ... and sluggish, you might have a condition called anemia. Anemia is a common blood disorder that many ...

  18. Family Key to Helping Teens Avoid Obesity

    Science.gov (United States)

    ... 159681.html Family Key to Helping Teens Avoid Obesity Good relationship with parents, especially between fathers and ... develop healthy habits that may protect them against obesity, a new study suggests. The researchers also found ...

  19. GSA IT Reform Cost Savings/Avoidance

    Data.gov (United States)

    General Services Administration — GSA IT provides data related to Agency IT initiatives that save or avoid expenditures. This data is provided as a requirement of OMB's Integrated Data Collection...

  20. Dual Eligibles and Potentially Avoidable Hospitalizations

    Data.gov (United States)

    U.S. Department of Health & Human Services — About 25 percent of the hospitalizations for dual eligible beneficiaries in 2005 were potentially avoidable. Medicare and Medicaid spending for those potentially...

  1. Avoid the Consequences of High Blood Pressure

    Science.gov (United States)

    ... Resources Stroke More Avoid the Consequences of High Blood Pressure Infographic Updated:Jun 19,2014 View a downloadable version of this infographic High Blood Pressure • Home • About High Blood Pressure (HBP) • Why HBP ...

  2. Active Collision Avoidance for Planetary Landers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advancements in radar technology have resulted in commercial, automotive collision avoidance radars. These radar systems typically use 37GHz or 77GHz interferometry...

  3. How to avoid overheating during exercise

    Science.gov (United States)

    ... patientinstructions/000865.htm How to avoid overheating during exercise To use the sharing features on this page, ... condition can get heat illness. Stay Cool During Exercise Try these tips to help prevent heat-related ...

  4. Self-Assessment of the Use of Plagiarism Avoiding Techniques to Create Ethical Scholarship Among Research Students

    OpenAIRE

    Saeed Ahmad; Ahsan Ullah

    2015-01-01

    The use of plagiarism avoiding techniques can be helpful to maintain academic integrity, a better learning environment and intellectual honesty. This explored the use of plagiarism avoiding techniques for creating ethical scholarship among research students. It also measured the association between the frequency of using plagiarism avoiding techniques and the satisfaction about knowledge of plagiarism. Data were collected from seven universities through an online self-struct...

  5. Information Dilemmas and Blame-Avoidance Strategies

    DEFF Research Database (Denmark)

    Erik, Baekkeskov; Rubin, Olivier

    2016-01-01

    from day one about 2009 H1N1 flu. To explore why, this article links crisis information dilemmas to blame avoidance concepts from democratic political theories. We argue that greater Chinese transparency about infectious disease response reflects evolution in blame avoidance, from heavy reliance...... in place public health specialists and institutions as responsible for H1N1 information and responses, thereby insulating the top-tier leadership....

  6. Mobile Robot Collision Avoidance in Human Environments

    Directory of Open Access Journals (Sweden)

    Lingqi Zeng

    2013-01-01

    Full Text Available Collision avoidance is a fundamental requirement for mobile robots. Avoiding moving obstacles (also termed dynamic obstacles with unpredictable direction changes, such as humans, is more challenging than avoiding moving obstacles whose motion can be predicted. Precise information on the future moving directions of humans is unobtainable for use in navigation algorithms. Furthermore, humans should be able to pursue their activities unhindered and without worrying about the robots around them. In this paper, both active and critical regions are used to deal with the uncertainty of human motion. A procedure is introduced to calculate the region sizes based on worst‐case avoidance conditions. Next, a novel virtual force field‐based mobile robot navigation algorithm (termed QVFF is presented. This algorithm may be used with both holonomic and nonholonomic robots. It incorporates improved virtual force functions for avoiding moving obstacles and its stability is proven using a piecewise continuous Lyapunov function. Simulation and experimental results are provided for a human walking towards the robot and blocking the path to a goal location. Next, the proposed algorithm is compared with five state‐of‐the‐art navigation algorithms for an environment with one human walking with an unpredictable change in direction. Finally, avoidance results are presented for an environment containing three walking humans. The QVFF algorithm consistently generated collision‐free paths to the goal.

  7. Avoidance Expression in Rats as a Function of Signal-Shock Interval: Strain and Sex Differences

    Directory of Open Access Journals (Sweden)

    Richard J Servatius

    2015-07-01

    Full Text Available Inbred Wistar Kyoto (WKY rats express inhibited temperament, increased sensitivity to stress, and exaggerated expressions of avoidance. A long-standing observation for lever press escape/avoidance learning in rats is the duration of the warning signal (WS determines whether avoidance is expressed over escape. Outbred female Sprague-Dawley (SD rats trained with a 10-s WS efficiently escaped, but failed to exhibit avoidance; avoidance was exhibited to a high degree with WSs longer than 20-s. We examined this longstanding WS duration function and extended it to male SD and male and female WKY rats. A cross-over design with two WS durations (10 s or 60 s was employed. Rats were trained (20 trials/session in four phases: acquisition (10 sessions, extinction (10 sessions, re-acquisition (8 sessions and re-extinction (8 sessions. Consistent with the literature, female and male SD rats failed to express avoidance to an appreciable degree with a 10-s WS. When these rats were switched to a 60-s WS, performance levels in the initial session of training resembled the peak performance of rats trained with a 60-s WS. Therefore, the avoidance relationship was acquired, but not expressed at 10-s WS. Further, poor avoidance at 10-s does not adversely affect expression at 60-s. Failure to express avoidance with a 10-s WS likely reflects contrasting reinforcement value of avoidance, not a reduction in the amount of time available to respond or competing responses. In contrast, WKY rats exhibited robust avoidance with a 10-s WS, which was most apparent in female WKY rats. Exaggerated expression of avoidances by WKY rats, especially female rats, further confirms this inbred strain as a model of anxiety vulnerability.

  8. The Role of Informative and Ambiguous Feedback in Avoidance Behavior: Empirical and Computational Findings

    Science.gov (United States)

    Moustafa, Ahmed A.; Sheynin, Jony; Myers, Catherine E.

    2015-01-01

    Avoidance behavior is a critical component of many psychiatric disorders, and as such, it is important to understand how avoidance behavior arises, and whether it can be modified. In this study, we used empirical and computational methods to assess the role of informational feedback and ambiguous outcome in avoidance behavior. We adapted a computer-based probabilistic classification learning task, which includes positive, negative and no-feedback outcomes; the latter outcome is ambiguous as it might signal either a successful outcome (missed punishment) or a failure (missed reward). Prior work with this task suggested that most healthy subjects viewed the no-feedback outcome as strongly positive. Interestingly, in a later version of the classification task, when healthy subjects were allowed to opt out of (i.e. avoid) responding, some subjects (“avoiders”) reliably avoided trials where there was a risk of punishment, but other subjects (“non-avoiders”) never made any avoidance responses at all. One possible interpretation is that the “non-avoiders” valued the no-feedback outcome so positively on punishment-based trials that they had little incentive to avoid. Another possible interpretation is that the outcome of an avoided trial is unspecified and that lack of information is aversive, decreasing subjects’ tendency to avoid. To examine these ideas, we here tested healthy young adults on versions of the task where avoidance responses either did or did not generate informational feedback about the optimal response. Results showed that provision of informational feedback decreased avoidance responses and also decreased categorization performance, without significantly affecting the percentage of subjects classified as “avoiders.” To better understand these results, we used a modified Q-learning model to fit individual subject data. Simulation results suggest that subjects in the feedback condition adjusted their behavior faster following better

  9. Avoiding barriers in control of mowing robot

    Institute of Scientific and Technical Information of China (English)

    QIU Bai-jing; QIAN Guo-hong; XIANG Zhong-ping; LI Zuo-peng

    2006-01-01

    Due to complicated barriers,it is difficult to track the path of the mowing robot and to avoid barriers.In order to solve the problem,a method based on distance-measuring sensors and fuzzy control inputs was proposed.Its track was composed of beelines and was easy to tail.The fuzzy control inputs were based on the front barrier distance and the difference between the left and right barrier distance measured by ultrasonic sensors;the output was the direction angle.The infrared sensors around the robot improved its safety in avoiding barriers.The result of the method was feasible,agile,and stable.The distance between the robot and the barriers could be changed by altering the inputs and outputs of fuzzy control and the length of the beelines.The disposed sensors can fulfill the need of the robot in avoiding barriers.

  10. Avoidable cancers in the Nordic countries. Radiation

    DEFF Research Database (Denmark)

    Winther, J F; Ulbak, Kaare; Dreyer, L;

    1997-01-01

    cases of lung cancer (1% of all lung cancer cases) per year could be avoided in the Nordic countries around the year 2000 if indoor exposure to radon were eliminated, and that an additional 720 cases (6%) could be avoided annually if either radon or tobacco smoking were eliminated. Similarly......Exposure to solar and ionizing radiation increases the risk for cancer in humans. Some 5% of solar radiation is within the ultraviolet spectrum and may cause both malignant melanoma and non-melanocytic skin cancer; the latter is regarded as a benign disease and is accordingly not included in our...... estimation of avoidable cancers. Under the assumption that the rate of occurrence of malignant melanoma of the buttocks of both men and women and of the scalp of women would apply to all parts of the body in people completely unexposed to solar radiation, it was estimated that approximately 95% of all...

  11. Engaging Math-Avoidant College Students

    Directory of Open Access Journals (Sweden)

    M. Paul Latiolais

    2009-07-01

    Full Text Available This paper is an informal, personal account of how we, as two college teachers, became interested in math anxiety, decided to explore it amongst students at our institution in order to inform our teaching, and became convinced that the massive problem is math avoidance. We tried discussion groups, but few students attended, although those that did made useful suggestions. Thus informed, we designed an innovative course, Confronting College Mathematics as a Humanities course with the possibility of credit toward the math requirement, but it was undersubscribed in its first offering and had to be canceled. How can we get college students who avoid math to break through the barrier of math avoidance? We have now begun to explore a new approach: Second Life, where students can engage math—and quantitative literacy—virtually, and anonymously.

  12. A collision avoidance system for workpiece protection

    Energy Technology Data Exchange (ETDEWEB)

    Schmitt, D.J.; Weber, T.M.; Novak, J.L. [Sandia National Labs., Albuquerque, NM (United States); Maslakowski, J.E. [Rockwell International Corp., Canoga Park, CA (United States). Rocketdyne Div.

    1995-04-01

    This paper describes an application of Sandia`s non-contact capacitive sensing technology for collision avoidance during the manufacturing of rocket engine thrust chambers. The collision avoidance system consists of an octagon shaped collar with a capacitive proximity sensor mounted on each face. The sensors produced electric fields which extend several inches from the face of the collar and detect potential collisions between the robot and the workpiece. A signal conditioning system processes the sensor output and provides varying voltage signals to the robot controller for stopping the robot.

  13. Inductive Learning

    Institute of Scientific and Technical Information of China (English)

    吴信东

    1993-01-01

    Machine learning(ML)is a major subfield of artificial intelligence(AI).It has been seen as a feasible way of avoiding the knowledge bottleneck problem in knowledge-based systems development.Research on ML has concentrated in the main on inductive learning,a paradigm for inducing rules from unordered sets of exmaples.AQ11 and ID3,the two most widespred algorithms in ML,are both inductive.This paper first summarizes AQ11,ID3 and the newly-developed extension matrix approach based HCV algorithm;and then reviews the recent development of inductive learing and automatic knowledge acquisition from data bases.

  14. Steps to Take with the Board to Avoid Walking the Plank.

    Science.gov (United States)

    Papallo, William R.

    1990-01-01

    A veteran superintendent outlines an eight-step method for achieving success, including assessing the situation, avoiding board overload, coping with stress, deemphasizing egoism, learning to live in the gray zone between policy formation and administration, ensuring effective board decisions, identifying prospective board members, and knowing…

  15. Intrahippocampal Insulin Improves Memory in a Passive-Avoidance Task in Male Wistar Rats

    Science.gov (United States)

    Babri, Shirin; Badie, Hamid Gholamipour; Khamenei, Saeed; Seyedlar, Mehdi Ordikhani

    2007-01-01

    The main impacts of insulin favor the peripheral organs. Although it functions as a neuropeptide, insulin possesses also some central effects. The aim of this study was to determine the effect of intrahippocampal infusion of insulin on passive avoidance learning in healthy male rats. Thirty male wistar rats were divided into three groups (n = 10…

  16. Levels of arginine-vasopressin in cerebrospinal fluid during passive avoidance behavior in rats

    NARCIS (Netherlands)

    Kloet, E.R. de; Laczi, F.; Gaffori, O.; Fekete, M.; Wied, D. de

    1984-01-01

    The concentration of immunoreactive arginine-vasopressin (IR-AVP) was measured in the cerebrospinal fluid (CSF) during acquisition and retention of passive avoidance behavior. IR-AVP level in CSF of male Wistar rats immediately after the learning trial was increased; the rate of which was related to

  17. Using Sounder Foundations to Help Avoid the "Why New Teachers Cry" Phenomenon

    Science.gov (United States)

    Duck, Lloyd

    2007-01-01

    How can we avoid the "why new teachers cry" phenomenon and the high dropout rate for beginning teachers? Start teacher preparation with an introductory foundations class that is experience based and allows students to study themselves and their preferences for teaching styles, learning styles, and classroom management by living through case…

  18. Anterograde effects of a single electroconvulsive shock on inhibitory avoidance and on cued fear conditioning

    Directory of Open Access Journals (Sweden)

    Oliveira M.G.M.

    1998-01-01

    Full Text Available A single electroconvulsive shock (ECS or a sham ECS was administered to male 3-4-month-old Wistar rats 1, 2, and 4 h before training in an inhibitory avoidance test and in cued classical fear conditioning (measured by means of freezing time in a new environment. ECS impaired inhibitory avoidance at all times and, at 1 or 2 h before training, reduced freezing time before and after re-presentation of the ECS. These results are interpreted as a transient conditioned stimulus (CS-induced anxiolytic or analgesic effect lasting about 2 h after a single treatment, in addition to the known amnesic effect of the stimulus. This suggests that the effect of anterograde learning impairment is demonstrated unequivocally only when the analgesic/anxiolytic effect is over (about 4 h after ECS administration and that this impairment of learning is selective, affecting inhibitory avoidance but not classical fear conditioning to a discrete stimulus.

  19. Odor-cued taste avoidance: a simple and robust test of mouse olfaction.

    Science.gov (United States)

    Slotnick, Burton; Coppola, David M

    2015-05-01

    In odor-cued taste avoidance (OCTA), thirsty mice, offered either an odorized nonaversive fluid (S+) or an odorized aversive fluid (S-), quickly learn to use odor to avoid drinking the S-. Acquisition of both odor detection and odor discrimination tasks is very rapid with learning evidenced in most cases by either long response times or total avoidance on the second presentation of the S- stimulus. OCTA is perhaps one of the simplest conditioning procedures for assessing olfaction in mice; it requires only a test box, drinkometer circuit, and thirsty mice accustomed to drinking in the apparatus. Its advantages over the most commonly used alternatives, habituation-dishabituation, and the mouse dig test, are discussed.

  20. No man is an island: the need to belong and dismissing avoidant attachment style.

    Science.gov (United States)

    Carvallo, Mauricio; Gabriel, Shira

    2006-05-01

    The need to belong theory proposes that all human beings need social connections. However, dismissive avoidant individuals claim to be comfortable without close relationships and appear to be indifferent to how other people think of them. The current studies examined the association between dismissing avoidant attachment and the desire to feel accepted by others. In Study 1, high-dismissive participants reported experiencing higher than average levels of positive affect and state self-esteem after learning that other participants accepted them. In Study 2, high-dismissive participants felt better about themselves and experienced higher levels of positive affect after learning that in the future they would be successful in interpersonal relative to independent domains or controls. The results of these studies suggest that dismissive avoidants do not represent a counterexample to the hypothesis that all human beings have a fundamental need and desire to belong.

  1. Avoidance Motivation and Conservation of Energy

    NARCIS (Netherlands)

    Roskes, Marieke; Elliot, Andrew J.; Nijstad, Bernard A.; De Dreu, Carsten K. W.

    2013-01-01

    Compared to approach motivation, avoidance motivation evokes vigilance, attention to detail, systematic information processing, and the recruitment of cognitive resources. From a conservation of energy perspective it follows that people would be reluctant to engage in the kind of effortful cognitive

  2. Hydrofluoric acid on dentin should be avoided.

    NARCIS (Netherlands)

    Loomans, B.A.C.; Mine, A.; Roeters, F.J.M.; Opdam, N.J.M.; Munck, J. De; Huysmans, M.C.D.N.J.M.; Meerbeek, B. Van

    2010-01-01

    Hydrofluoric acid can be used for intra-oral repair of restorations. Contamination of tooth substrate with hydrofluoric acid cannot always be avoided. OBJECTIVES: To investigate the bonding effectiveness to hydrofluoric acid contaminated dentin by, micro-tensile bond strength testing, SEM and TEM. M

  3. Teaching Preschool Children to Avoid Poison Hazards

    Science.gov (United States)

    Dancho, Kelly A.; Thompson, Rachel H.; Rhoades, Melissa M.

    2008-01-01

    We evaluated the effectiveness of group safety training and in situ feedback and response interruption to teach preschool children to avoid consuming potentially hazardous substances. Three children ingested ambiguous substances during a baited baseline assessment condition and continued to ingest these substances following group safety training.…

  4. Reasonable Avoidability, Responsibility and Lifestyle Diseases

    DEFF Research Database (Denmark)

    Andersen, Martin Marchman

    2012-01-01

    In “Health, Luck and Justice” Shlomi Segall argues for a luck egalitarian approach to justice in health care. As the basis for a just distribution he suggests a principle of Reasonable Avoidability, which he takes to imply that we do not have justice-based reasons to treat diseases brought about ...

  5. Your Adolescent: Anxiety and Avoidant Disorders

    Science.gov (United States)

    ... the problem manifests in school avoidance, the initial goal will be to get the youngster back to school as soon as possible. Cognitive-Behavioral Therapy In many cases, cognitive-behavioral psychotherapy techniques are effective in addressing adolescent anxiety disorders. ...

  6. Avoidance: From threat encounter to action execution

    NARCIS (Netherlands)

    I. Arnaudova

    2015-01-01

    Every day we encounter many threats to survival: a car speeding on a small street or an angry neighbor carrying an axe. Mostly, people go through their days not worrying that their chance of survival might be small. They avoid many dangers without even thinking about them (e.g., looking at both side

  7. Oscillations in two-person avoidance control

    CERN Document Server

    Kish, Lazar

    2016-01-01

    Social interaction dynamics are a special type of group interactions that play a large part in our everyday lives. They dictate how and with whom a certain individual will interact. One of such interactions can be termed "avoidance control". This everyday situation occurs when two fast-walking persons suddenly realize that they are on a frontal collision course and begin maneuvering to avoid collision. If the two walkers' initial maneuverings are in the same direction that can lead to oscillations that lengthen time required to reach a stable avoidance trajectory. We introduce a dynamical model with a feedback loop to understand the origin and properties of this oscillation. For the emergence of the oscillatory behavior, two conditions must be satisfied: i) the persons must initiate the avoidance maneuver in the same direction; ii) the time delays in the feedback loop must reverse the phase of the players' positions at the oscillation frequency. The oscillation can be terminated at any time if one of the walk...

  8. Pathogen evolution under host avoidance plasticity.

    Science.gov (United States)

    McLeod, David V; Day, Troy

    2015-09-01

    Host resistance consists of defences that limit pathogen burden, and can be classified as either adaptations targeting recovery from infection or those focused upon infection avoidance. Conventional theory treats avoidance as a fixed strategy which does not vary from one interaction to the next. However, there is increasing empirical evidence that many avoidance strategies are triggered by external stimuli, and thus should be treated as phenotypically plastic responses. Here, we consider the implications of avoidance plasticity for host-pathogen coevolution. We uncover a number of predictions challenging current theory. First, in the absence of pathogen trade-offs, plasticity can restrain pathogen evolution; moreover, the pathogen exploits conditions in which the host would otherwise invest less in resistance, causing resistance escalation. Second, when transmission trades off with pathogen-induced mortality, plasticity encourages avirulence, resulting in a superior fitness outcome for both host and pathogen. Third, plasticity ensures the sterilizing effect of pathogens has consequences for pathogen evolution. When pathogens castrate hosts, selection forces them to minimize mortality virulence; moreover, when transmission trades off with sterility alone, resistance plasticity is sufficient to prevent pathogens from evolving to fully castrate. PMID:26336170

  9. The Advocacy or Avoidance of Only Children.

    Science.gov (United States)

    Falbo, Toni

    A brief review of the psychological literature on the characteristics of only children is presented in order to determine if the one-child family should be avoided or advocated. The relevant literature is found to be limited in quantity and conceptualization of the only child. Previous literature is divided into three types of study: those with…

  10. Obsessive compulsive disorder with pervasive avoidance

    OpenAIRE

    Sharma Parul; Sharma Ravi; Kumar Ramesh; Sharma Dinesh

    2009-01-01

    Obsessive compulsive disorder (OCD) is a common disorder, but some of its atypical presentations are uncommon and difficult to diagnose. We report one such case which on initial presentation appeared to be psychotic protocol but after detailed workup was diagnosed as OCD with marked avoidance symptoms.

  11. Obesity and Healthcare Avoidance: A Systematic Review

    Directory of Open Access Journals (Sweden)

    Robert D McGuigan

    2015-03-01

    Full Text Available This review addresses the issue of health care avoidance and obesity. English language journal articles published between 1990 and 2012 that addressed the review question|“is being overweight or obese an unrecognized factor in healthcare avoidance?” were located using major databases. A modified JADAD scoring system was then used to assess papers. Ten papers were identified which directly addressed the review question. A positive relationship exists between obesity and healthcare avoidance. The major contributory factors were being female, have a diagnosed mental health problem and perceived or actual bias and discrimination by health professionals. The review also highlights the importance of the relationship between healthcare professionals and their patients, and the physical environment in which interactions occur as these may contribute to avoidance behaviors. Concern about obesity is rising and while there has been much discussion about strategies to reduce obesity this review highlights the need for thinking more broadly about the way in which overweight and obese individuals interact with preventative health strategies.

  12. HOW TO AVOID SEXIST LANGUAGE IN ENGLISH

    Institute of Scientific and Technical Information of China (English)

    HuZhiqing

    2004-01-01

    Use of Sexist language is one of the serious yet often-neglected mistakes in the English writing and speaking of Chineselearners of English. Sexist language in English can be classifiedinto two categories : ambiguity of referent and stereotyping. Thispaper focuses on some common sexist language in the Englishwriting and speaking of Chinese learners of English and givessome suggestions about how to avoid them.

  13. Doppler micro sense and avoid radar

    Science.gov (United States)

    Gorwara, Ashok; Molchanov, Pavlo; Asmolova, Olga

    2015-10-01

    There is a need for small Sense and Avoid (SAA) systems for small and micro Unmanned Aerial Systems (UAS) to avoid collisions with obstacles and other aircraft. The proposed SAA systems will give drones the ability to "see" close up and give them the agility to maneuver through tight areas. Doppler radar is proposed for use in this sense and avoid system because in contrast to optical or infrared (IR) systems Doppler can work in more harsh conditions such as at dusk, and in rain and snow. And in contrast to ultrasound based systems, Doppler can better sense small sized obstacles such as wires and it can provide a sensing range from a few inches to several miles. An SAA systems comprised of Doppler radar modules and an array of directional antennas that are distributed around the perimeter of the drone can cover the entire sky. These modules are designed so that they can provide the direction to the obstacle and simultaneously generate an alarm signal if the obstacle enters within the SAA system's adjustable "Protection Border". The alarm signal alerts the drone's autopilot to automatically initiate an avoidance maneuver. A series of Doppler radar modules with different ranges, angles of view and transmitting power have been designed for drones of different sizes and applications. The proposed Doppler radar micro SAA system has simple circuitry, works from a 5 volt source and has low power consumption. It is light weight, inexpensive and it can be used for a variety of small unmanned aircraft.

  14. An Examination of Avoided Costs in Utah

    Energy Technology Data Exchange (ETDEWEB)

    Bolinger, Mark; Wiser, Ryan

    2005-01-07

    The Utah Wind Working Group (UWWG) believes there are currently opportunities to encourage wind power development in the state by seeking changes to the avoided cost tariff paid to qualifying facilities (QFs). These opportunities have arisen as a result of a recent renegotiation of Pacificorp's Schedule 37 tariff for wind QFs under 3 MW, as well as an ongoing examination of Pacificorp's Schedule 38 tariff for wind QFs larger than 3 MW. It is expected that decisions made regarding Schedule 38 will also impact Schedule 37. Through the Laboratory Technical Assistance Program (Lab TAP), the UWWG has requested (through the Utah Energy Office) that LBNL provide technical assistance in determining whether an alternative method of calculating avoided costs that has been officially adopted in Idaho would lead to higher QF payments in Utah, and to discuss the pros and cons of this method relative to the methodology recently adopted under Schedule 37 in Utah. To accomplish this scope of work, I begin by summarizing the current method of calculating avoided costs in Utah (per Schedule 37) and Idaho (the ''surrogate avoided resource'' or SAR method). I then compare the two methods both qualitatively and quantitatively. Next I present Pacificorp's four main objections to the use of the SAR method, and discuss the reasonableness of each objection. Finally, I conclude with a few other potential considerations that might add value to wind QFs in Utah.

  15. Organising European technical documentation to avoid duplication.

    Science.gov (United States)

    Donawa, Maria

    2006-04-01

    The development of comprehensive accurate and well-organised technical documentation that demonstrates compliance with regulatory requirements is a resource-intensive, but critically important activity for medical device manufacturers. This article discusses guidance documents and method of organising technical documentation that may help avoid costly and time-consuming duplication. PMID:16736662

  16. Simple Obstacle Avoidance Algorithm for Rehabilitation Robots

    NARCIS (Netherlands)

    Stuyt, F.H.A.; Römer, G.R.B.; Stuyt, H.J.A.

    2007-01-01

    The efficiency of a rehabilitation robot is improved by offering record-and-replay to operate the robot. While automatically moving to a stored target (replay) collisions of the robot with obstacles in its work space must be avoided. A simple, though effective, generic and deterministic algorithm fo

  17. Specific Language Impairment at Adolescence: Avoiding Complexity

    Science.gov (United States)

    Tuller, Laurice; Henry, Celia; Sizaret, Eva; Barthez, Marie-Anne

    2012-01-01

    This study explores complex language in adolescents with specific language impairment (SLI) with the aim of finding out how aspects of language characteristic of typical syntactic development after childhood fare and, in particular, whether there is evidence that individuals with SLI avoid using structures whose syntactic derivation involves…

  18. Working with Avoidant Children: A Clinical Challenge.

    Science.gov (United States)

    Berson, Nancy; Meisburger, Diana

    1998-01-01

    Presents strategies for interviewing and assisting highly avoidant children who may be victims of maltreatment. Discusses factors inhibiting their self-disclosure, the importance of managing child safety, and establishing and maintaining rapport. Describes strategies including pacing the interview, empowering the child, and using distancing…

  19. Bursting neurons and ultrasound avoidance in crickets.

    Science.gov (United States)

    Marsat, Gary; Pollack, Gerald S

    2012-01-01

    Decision making in invertebrates often relies on simple neural circuits composed of only a few identified neurons. The relative simplicity of these circuits makes it possible to identify the key computation and neural properties underlying decisions. In this review, we summarize recent research on the neural basis of ultrasound avoidance in crickets, a response that allows escape from echolocating bats. The key neural property shaping behavioral output is high-frequency bursting of an identified interneuron, AN2, which carries information about ultrasound stimuli from receptor neurons to the brain. AN2's spike train consists of clusters of spikes - bursts - that may be interspersed with isolated, non-burst spikes. AN2 firing is necessary and sufficient to trigger avoidance steering but only high-rate firing, such as occurs in bursts, evokes this response. AN2 bursts are therefore at the core of the computation involved in deciding whether or not to steer away from ultrasound. Bursts in AN2 are triggered by synaptic input from nearly synchronous bursts in ultrasound receptors. Thus the population response at the very first stage of sensory processing - the auditory receptor - already differentiates the features of the stimulus that will trigger a behavioral response from those that will not. Adaptation, both intrinsic to AN2 and within ultrasound receptors, scales the burst-generating features according to the stimulus statistics, thus filtering out background noise and ensuring that bursts occur selectively in response to salient peaks in ultrasound intensity. Furthermore AN2's sensitivity to ultrasound varies adaptively with predation pressure, through both developmental and evolutionary mechanisms. We discuss how this key relationship between bursting and the triggering of avoidance behavior is also observed in other invertebrate systems such as the avoidance of looming visual stimuli in locusts or heat avoidance in beetles.

  20. Bursting neurons and ultrasound avoidance in crickets

    Directory of Open Access Journals (Sweden)

    Gary eMarsat

    2012-07-01

    Full Text Available Decision making in invertebrates often relies on simple neural circuits composed of only a few identified neurons. The relative simplicity of these circuits makes it possible to identify the key computation and neural properties underlying decisions. In this review, we summarize recent research on the neural basis of ultrasound avoidance in crickets, a response that allows escape from echolocating bats. The key neural property shaping behavioral output is high-frequency bursting of an identified interneuron, AN2, which carries information about ultrasound stimuli from receptor neurons to the brain. AN2's spike train consists of clusters of spikes –bursts– that may be interspersed with isolated, non-burst spikes. AN2 firing is necessary and sufficient to trigger avoidance steering but only high-rate firing, such as occurs in bursts, evokes this response. AN2 bursts are therefore at the core of the computation involved in deciding whether or not to steer away from ultrasound. Bursts in AN2 are triggered by synaptic input from nearly synchronous bursts in ultrasound receptors. Thus the population response at the very first stage of sensory processing –the auditory receptor- already differentiates the features of the stimulus that will trigger a behavioral response from those that will not. Adaptation, both intrinsic to AN2 and within ultrasound receptors, scales the burst-generating features according to the stimulus statistics, thus filtering out background noise and ensuring that bursts occur selectively in response to salient peaks in ultrasound intensity. Furthermore AN2’s sensitivity to ultrasound varies adaptively with predation pressure, through both developmental and evolutionary mechanisms. We discuss how this key relationship between bursting and the triggering of avoidance behavior is also observed in other invertebrate systems such as the avoidance of looming visual stimuli in locusts or heat avoidance in beetles.

  1. Measuring Patients’ Attachment Avoidance in Psychotherapy: Development of the Attachment Avoidance in Therapy Scale (AATS

    Directory of Open Access Journals (Sweden)

    András Láng

    2012-11-01

    Full Text Available A new scale measuring patient-therapist attachment avoidance was developed. Attachment Avoidance in Therapy Scale is a new measure based on the Bartholomew model of adult attachment (Bartholomew & Horowitz, 1991 and the Experience in Close Relationships Scale (Brennan, Clark, & Shaver, 1998 to measure patients’ attachment avoidance towards therapists. With 112 patient-therapist dyads participating in the study, validation of a preliminary scale – measuring both attachment anxiety and attachment avoidance in therapy – took place using therapists’ evaluations of patients’ relational behavior and patients’ self-reports about their attitude toward psychotherapy. Analysis of the data revealed six underlying scales. Results showed all six scales to be reliable. Validation of scales measuring attachment anxiety failed. The importance of Attachment Avoidance in Therapy Scale and its subscales is discussed.

  2. Context-dependent activation of reduced autobiographical memory specificity as an avoidant coping style.

    Science.gov (United States)

    Debeer, Elise; Raes, Filip; Williams, J Mark G; Hermans, Dirk

    2011-12-01

    According to the affect-regulation hypothesis (Williams et al., 2007), reduced autobiographical memory specificity (rAMS) or overgeneral memory (OGM) might be considered a cognitive avoidance strategy; that is, people learn to avoid the emotionally painful consequences associated with the retrieval of specific negative memories. Based on this hypothesis, one would predict significant negative associations between AMS and avoidant coping. However, studies investigating this prediction have led to equivocal results. In the present study we tested a possible explanation for these contradictory findings. It was hypothesized that rAMS (in part) reflects an avoidant coping strategy, which might only become apparent under certain conditions, that is, conditions that signal the possibility of 'danger.' To test this hypothesis, we assessed AMS and behavioral avoidance but experimentally manipulated the instructions. In the neutral condition, two parallel versions of the Autobiographical Memory Test (AMT) were presented under neutral instructions. In the threat condition, the first AMT was presented under neutral instructions, while the second AMT was presented under 'threat instructions.' Results showed no significant correlations between avoidance and OGM under neutral conditions but significant and markedly stronger correlations under threat conditions, with more avoidance being associated with fewer specific and more categoric memories. In addition, high avoiders showed a stronger reduction in AMS in the threat condition as compared with the neutral condition, while low avoiders showed no such difference between conditions. The data confirm that OGM can be considered as part of a broader avoidant coping style. However, more importantly, they show that, at least in nonclinical individuals, the activation of this coping style may depend on the context.

  3. Session: Avoiding, minimizing, and mitigating avian and bat impacts

    Energy Technology Data Exchange (ETDEWEB)

    Thelander, Carl; Kerlinger, Paul

    2004-09-01

    This session at the Wind Energy and Birds/Bats workshop consisted of two presentations followed by a discussion/question answer period. The session addressed a variety of questions related to avoiding, minimizing, and mitigating the avian and bat impacts of wind power development including: what has been learned from operating turbines and mitigating impacts where they are unavoidable, such as at Altamont Pass WRA, and should there be mitigation measures such as habitat creation or land conservation where impacts occur. Other impact minimization and mitigation approaches discussed included: location and siting evaluations; options for construction and operation of wind facilities; turbine lighting; and the physical alignment/orientation. Titles and authors of the presentations were: 'Bird Fatalities in the Altamont Pass Wind Resource Area: A Case Study, Part II' by Carl Thelander and 'Prevention and Mitigation of Avian Impacts at Wind Power Facilities' by Paul Kerlinger.

  4. Learning and Memory in Infants.

    Science.gov (United States)

    Lipsitt, Lewis P.

    1990-01-01

    Discusses important recent strides in the documentation and understanding of the infant's learning and memory capacity. Focuses on the psychobiology of learning, hedonic mediation of approach-avoidance and learned behavior, infant memory, and critical conditions of infancy and behavioral misadventures. (RJC)

  5. Converging evidence of social avoidant behavior in schizophrenia from two approach-avoidance tasks.

    Science.gov (United States)

    de la Asuncion, Javier; Docx, Lise; Sabbe, Bernard; Morrens, Manuel; de Bruijn, Ellen R A

    2015-10-01

    Many people with schizophrenia suffer from social impairments characterized by active social avoidance, which is related to social phobia common in schizophrenia, while motivational impairments can also result in passive social withdrawal. Although social avoidance is frequently reported in this population, this is the first study to directly compare approach-avoidance tendencies in schizophrenia patients (N = 37) and healthy controls (N = 29). Participants performed two tasks: a computerized approach-avoidance task (AAT) to assess response tendencies toward images of happy and angry faces with direct or averted gaze and a one-to-one personal space test (PST) to gauge more naturalistic approach-avoidance behaviors toward a real person bearing a neutral expression. The AAT results showed that both groups showed faster avoidance responses to angry faces and faster approach responses to happy faces with a direct gaze. Happy faces with averted gaze, however, resulted in faster avoidance responses in the patient group only. On the PST, the patients approached the experimenter less than healthy controls did. This measure of interpersonal distance was positively related to positive symptom severity. Delusions of reference and increased sensitivity to social rejection may explain the patients' avoidance tendencies in response to pictures of happy faces with averted gaze and in the presence of an actual person. The current findings demonstrate the importance of others adopting positive and unambiguous attitudes when interacting with schizophrenia patients to minimize behavioral avoidance patterns, which is particularly relevant for relatives and clinicians whose interactions with the patients are crucial to facilitating treatment and promoting healthy social relationships.

  6. The Feasibility of Avoiding Future Climate Impacts: Results from the AVOID Programmes

    Science.gov (United States)

    Lowe, J. A.; Warren, R.; Arnell, N.; Buckle, S.

    2014-12-01

    The AVOID programme and its successor, AVOID2, have focused on answering three core questions: how do we characterise potentially dangerous climate change and impacts, which emissions pathways can avoid at least some of these impacts, and how feasible are the future reductions needed to significantly deviate from a business-as-usual future emissions pathway. The first AVOID project succeeded in providing the UK Government with evidence to inform its position on climate change. A key part of the work involved developing a range of global emissions pathways and estimating and understanding the corresponding global impacts. This made use of a combination of complex general circulation models, simple climate models, pattern-scaling and state-of-the art impacts models. The results characterise the range of avoidable impacts across the globe in several key sectors including river and coastal flooding, cooling and heating energy demand, crop productivity and aspects of biodiversity. The avoided impacts between a scenario compatible with a 4ºC global warming and one with a 2ºC global warming were found to be highly sector dependent and avoided fractions typically ranged between 20% and 70%. A further key aspect was characterising the magnitude of the uncertainty involved, which is found to be very large in some impact sectors although the avoided fraction appears a more robust metric. The AVOID2 programme began in 2014 and will provide results in the run up to the Paris CoP in 2015. This includes new post-IPCC 5th assessment evidence to inform the long-term climate goal, a more comprehensive assessment of the uncertainty ranges of feasible emission pathways compatible with the long-term goal and enhanced estimates of global impacts using the latest generation of impact models and scenarios.

  7. Optical Flow based Robot Obstacle Avoidance

    Directory of Open Access Journals (Sweden)

    Kahlouche Souhila

    2008-11-01

    Full Text Available In this paper we try to develop an algorithm for visual obstacle avoidance of autonomous mobile robot. The input of the algorithm is an image sequence grabbed by an embedded camera on the B21r robot in motion. Then, the optical flow information is extracted from the image sequence in order to be used in the navigation algorithm. The optical flow provides very important information about the robot environment, like: the obstacles disposition, the robot heading, the time to collision and the depth. The strategy consists in balancing the amount of left and right side flow to avoid obstacles, this technique allows robot navigation without any collision with obstacles. The robustness of the algorithm will be showed by some examples.

  8. Construction dispute research conceptualisation, avoidance and resolution

    CERN Document Server

    2014-01-01

    There are three specific purposes of Construction Dispute Research. First, this volume aims to summarise studies on construction dispute. Second, apart from the theoretical constructs, where appropriate empirical tests are also included. This approach serves to go beyond the commonly used anecdotal approach for the subject matters. Third, it is the sincere hope of the authors that this book will help shaping research agenda of construction dispute.  The studies are mostly framed from a management perspective drawing on methods and concepts in contract law, economics, psychology and management science.   The book has twenty chapters that are arranged in four parts covering conceptualisation, avoidance, negotiation and mediation. Part 1 is devoted for dispute conceptualisation. A building is only as strong as its foundation. Thus it is no better start to study construction dispute by conceptualisation. The theme of Part 2 is dispute avoidance. The conventional wisdom of ‘prevention is better than cure’ se...

  9. Inhibited Sexual Desire and Sexual Avoidance

    OpenAIRE

    Morse, William I.

    1985-01-01

    Inhibited sexual desire (ISD) is one of the most common sexual dysfunctions, especially in women. Family physicians have an opportunity to recognize ISD before the associated problems become entrenched, and to guide couples toward satisfactory resolution. A summary is presented of current thinking on ISD and its causes. Case reports and observations about frequency of and treatment for ISD are included. Much less has been written about sexual avoidance in the presence of desire. A definition ...

  10. Anorexia nervosa and food avoidance emotional disorder.

    OpenAIRE

    Higgs, J F; Goodyer, I M; Birch, J.

    1989-01-01

    A retrospective and longitudinal study was carried out on all children and adolescents who presented to a child psychiatry service over a period of 26 years to identify the nature, course, and outcome of cases meeting criteria for anorexia nervosa (n = 27). Two groups of the same age were identified for comparison, firstly those with food avoidance and emotional disorders (n = 23), and secondly those with emotional disorders but no symptoms associated with eating (n = 22). The results confirm...

  11. Robot maps, robot moves, robot avoids

    OpenAIRE

    Farrugia, Claire; Duca, Edward

    2014-01-01

    Robotics is a cornerstone for this century’s innovations. From robot nurses to your own personal assistant, most robots need to know: ‘where is it?’ ‘Where should it go?’ And ‘how to get there?’ Without answers to these questions a robot cannot do much. http://www.um.edu.mt/think/robot-maps-robot-moves-robot-avoids/

  12. Can subjectivity be avoided in translation evaluation?

    OpenAIRE

    Segers, Winibert; Kockaert, Hendrik

    2015-01-01

    The didactics of translation and interpreting Testing and assessment criteria and methods Can subjectivity be avoided in translation evaluation? Winibert Segers & Hendrik J Kockaert, KU Leuven Camiel Paulusstraat 8, 2630 Aartselaar, België Is translation evaluation a subjective, personal matter? Is evaluating translations the same as beer tasting or listening to a piece of music? Is the judgment determined by personal taste? We will try to answe...

  13. Normal coronary arteriogram. An avoidable test?

    OpenAIRE

    Ilsley, C; Stockley, A; Clitsakis, D; Layton, C

    1982-01-01

    Between 10 and 20% of coronary arteriograms in patients with chest pain show normal vessels, often in association with a history of "atypical" angina. Conventional non-invasive tests are inaccurate in this group of patients compared with those with classical angina. This study prospectively evaluates combined 12 lead exercise electrocardiography and thallium-201 scintigraphy as a screening test in patients with atypical angina in order to determine whether normal arteriograms are avoidable in...

  14. Airborne Collision Detection and Avoidance for Small UAS Sense and Avoid Systems

    Science.gov (United States)

    Sahawneh, Laith Rasmi

    The increasing demand to integrate unmanned aircraft systems (UAS) into the national airspace is motivated by the rapid growth of the UAS industry, especially small UAS weighing less than 55 pounds. Their use however has been limited by the Federal Aviation Administration regulations due to collision risk they pose, safety and regulatory concerns. Therefore, before civil aviation authorities can approve routine UAS flight operations, UAS must be equipped with sense-and-avoid technology comparable to the see-and-avoid requirements for manned aircraft. The sense-and-avoid problem includes several important aspects including regulatory and system-level requirements, design specifications and performance standards, intruder detecting and tracking, collision risk assessment, and finally path planning and collision avoidance. In this dissertation, our primary focus is on developing an collision detection, risk assessment and avoidance framework that is computationally affordable and suitable to run on-board small UAS. To begin with, we address the minimum sensing range for the sense-and-avoid (SAA) system. We present an approximate close form analytical solution to compute the minimum sensing range to safely avoid an imminent collision. The approach is then demonstrated using a radar sensor prototype that achieves the required minimum sensing range. In the area of collision risk assessment and collision prediction, we present two approaches to estimate the collision risk of an encounter scenario. The first is a deterministic approach similar to those been developed for Traffic Alert and Collision Avoidance (TCAS) in manned aviation. We extend the approach to account for uncertainties of state estimates by deriving an analytic expression to propagate the error variance using Taylor series approximation. To address unanticipated intruders maneuvers, we propose an innovative probabilistic approach to quantify likely intruder trajectories and estimate the probability of

  15. Granting silence to avoid wireless collisions

    KAUST Repository

    Choi, Jung Il

    2010-10-01

    We describe grant-to-send, a novel collision avoidance algorithm for wireless mesh networks. Rather than announce packets it intends to send, a node using grant-to-send announces packets it expects to hear others send. We present evidence that inverting collision avoidance in this way greatly improves wireless mesh performance. Evaluating four protocols from 802.11 meshes and 802.15.4 sensor networks, we find that grant-to-send matches or outperforms CSMA and RTS/CTS in all cases. For example, in a 4-hop UDP flow, grantto- send can achieve 96% of the theoretical maximum throughput while maintaining a 99.9% packet delivery ratio. Grant-tosend is also general enough to replace protocol-specific collision avoidance mechanisms common to sensor network protocols. Grant-to-send is simple. For example, incorporating it into 802.11 requires only 11 lines of driver code and no hardware changes. Furthermore, as it reuses existing 802.11 mechanisms, grant-to-send inter-operates with current networks and can be incrementally deployed. © 2010 IEEE.

  16. Avoidable deaths in Greenland 1968-1985

    DEFF Research Database (Denmark)

    Bjerregaard, Peter; Juel, K

    1990-01-01

    The concept of avoidable deaths suggests that certain deaths ought not occur in a given society because it is possible to prevent or treat the disease or condition. A list of avoidable deaths is time and community specific as it reflects the socioeconomic conditions, professional medical capacity...... and alcohol related diseases were high in the capital and East Greenland and low in West Greenlandic settlements. It is concluded that further studies on preventable diseases and causes of death, in particular certain infectious diseases, accidents and suicides, are needed....... and political will of the society. A list of avoidable deaths is proposed for Greenland which includes, inter alia, meningitis, lung cancer, acute respiratory infections, suicides, boat accidents and alcohol related diseases and accidents. All were considerably more common in Greenland than in Denmark...... and several showed an increasing time trend. The regional patterns were particularly clear for infectious diseases and accidents, which showed low mortality rates in the capital and other towns and high mortality rates in settlements and in the remote East Greenland, while mortality rates from suicides...

  17. Traffic jam driving with NMV avoidance

    Science.gov (United States)

    Milanés, Vicente; Alonso, Luciano; Villagrá, Jorge; Godoy, Jorge; de Pedro, Teresa; Oria, Juan P.

    2012-08-01

    In recent years, the development of advanced driver assistance systems (ADAS) - mainly based on lidar and cameras - has considerably improved the safety of driving in urban environments. These systems provide warning signals for the driver in the case that any unexpected traffic circumstance is detected. The next step is to develop systems capable not only of warning the driver but also of taking over control of the car to avoid a potential collision. In the present communication, a system capable of autonomously avoiding collisions in traffic jam situations is presented. First, a perception system was developed for urban situations—in which not only vehicles have to be considered, but also pedestrians and other non-motor-vehicles (NMV). It comprises a differential global positioning system (DGPS) and wireless communication for vehicle detection, and an ultrasound sensor for NMV detection. Then, the vehicle's actuators - brake and throttle pedals - were modified to permit autonomous control. Finally, a fuzzy logic controller was implemented capable of analyzing the information provided by the perception system and of sending control commands to the vehicle's actuators so as to avoid accidents. The feasibility of the integrated system was tested by mounting it in a commercial vehicle, with the results being encouraging.

  18. Knowing and avoiding plagiarism during scientific writing.

    Science.gov (United States)

    Kumar, P Mohan; Priya, N Swapna; Musalaiah, Svvs; Nagasree, M

    2014-09-01

    Plagiarism has become more common in both dental and medical communities. Most of the writers do not know that plagiarism is a serious problem. Plagiarism can range from simple dishonesty (minor copy paste/any discrepancy) to a more serious problem (major discrepancy/duplication of manuscript) when the authors do cut-copy-paste from the original source without giving adequate credit to the main source. When we search databases like PubMed/MedLine there is a lot of information regarding plagiarism. However, it is still a current topic of interest to all the researchers to know how to avoid plagiarism. It's time to every young researcher to know ethical guidelines while writing any scientific publications. By using one's own ideas, we can write the paper completely without looking at the original source. Specific words from the source can be added by using quotations and citing them which can help in not only supporting your work and amplifying ideas but also avoids plagiarism. It is compulsory to all the authors, reviewers and editors of all the scientific journals to know about the plagiarism and how to avoid it by following ethical guidelines and use of plagiarism detection software while scientific writing.

  19. Urban water restrictions: Attitudes and avoidance

    Science.gov (United States)

    Cooper, Bethany; Burton, Michael; Crase, Lin

    2011-12-01

    In most urban cities across Australia, water restrictions remain the dominant policy mechanism to restrict urban water consumption. The extensive adoption of water restrictions as a means to limit demand, over several years, means that Australian urban water prices have consistently not reflected the opportunity cost of water. Given the generally strong political support for water restrictions and the likelihood that they will persist for some time, there is value in understanding households' attitudes in this context. More specifically, identifying the welfare gains associated with avoiding urban water restrictions entirely would be a nontrivial contribution to our knowledge and offer insights into the benefits of alternative policy responses. This paper describes the results from a contingent valuation study that investigates consumers' willingness to pay to avoid urban water restrictions. Importantly, the research also investigates the influence of cognitive and exogenous dimensions on the utility gain associated with avoiding water restrictions. The results provide insights into the impact of the current policy mechanism on economic welfare.

  20. Rapid Assessment of Avoidable Blindness in India.

    Directory of Open Access Journals (Sweden)

    John Neena

    Full Text Available BACKGROUND: Rapid assessment of avoidable blindness provides valid estimates in a short period of time to assess the magnitude and causes of avoidable blindness. The study determined magnitude and causes of avoidable blindness in India in 2007 among the 50+ population. METHODS AND FINDINGS: Sixteen randomly selected districts where blindness surveys were undertaken 7 to 10 years earlier were identified for a follow up survey. Stratified cluster sampling was used and 25 clusters (20 rural and 5 urban were randomly picked in each district.. After a random start, 100 individuals aged 50+ were enumerated and examined sequentially in each cluster. All those with presenting vision = 50 years were enumerated, and 94.7% examined. Based on presenting vision,, 4.4% (95% Confidence Interval[CI]: 4.1,4.8 were severely visually impaired (vision<6/60 to 3/60 in the better eye and 3.6% (95% CI: 3.3,3.9 were blind (vision<3/60 in the better eye. Prevalence of low vision (<6/18 to 6/60 in the better eye was 16.8% (95% CI: 16.0,17.5. Prevalence of blindness and severe visual impairment (<6/60 in the better eye was higher among rural residents (8.2%; 95% CI: 7.9,8.6 compared to urban (7.1%; 95% CI: 5.0, 9.2, among females (9.2%; 95% CI: 8.6,9.8 compared to males (6.5%; 95% CI: 6.0,7.1 and people above 70 years (20.6%; 95% CI: 19.1,22.0 compared to people aged 50-54 years (1.3%; 95% CI: 1.1,1.6. Of all blindness, 88.2% was avoidable. of which 81.9% was due to cataract and 7.1% to uncorrected refractive errors/uncorrected aphakia. CONCLUSIONS: Cataract and refractive errors are major causes of blindness and low vision and control strategies should prioritize them. Most blindness and low vision burden is avoidable.

  1. See-and-Avoid Collision Avoidance Using ADS-B Signal and Radar Sensing Project

    Data.gov (United States)

    National Aeronautics and Space Administration — IAI proposes an innovative collision avoidance radar and communication technology to detect and track both cooperative and non-cooperative targets. The system...

  2. Testing the role of reward and punishment sensitivity in avoidance behavior: a computational modeling approach.

    Science.gov (United States)

    Sheynin, Jony; Moustafa, Ahmed A; Beck, Kevin D; Servatius, Richard J; Myers, Catherine E

    2015-04-15

    Exaggerated avoidance behavior is a predominant symptom in all anxiety disorders and its degree often parallels the development and persistence of these conditions. Both human and non-human animal studies suggest that individual differences as well as various contextual cues may impact avoidance behavior. Specifically, we have recently shown that female sex and inhibited temperament, two anxiety vulnerability factors, are associated with greater duration and rate of the avoidance behavior, as demonstrated on a computer-based task closely related to common rodent avoidance paradigms. We have also demonstrated that avoidance is attenuated by the administration of explicit visual signals during "non-threat" periods (i.e., safety signals). Here, we use a reinforcement-learning network model to investigate the underlying mechanisms of these empirical findings, with a special focus on distinct reward and punishment sensitivities. Model simulations suggest that sex and inhibited temperament are associated with specific aspects of these sensitivities. Specifically, differences in relative sensitivity to reward and punishment might underlie the longer avoidance duration demonstrated by females, whereas higher sensitivity to punishment might underlie the higher avoidance rate demonstrated by inhibited individuals. Simulations also suggest that safety signals attenuate avoidance behavior by strengthening the competing approach response. Lastly, several predictions generated by the model suggest that extinction-based cognitive-behavioral therapies might benefit from the use of safety signals, especially if given to individuals with high reward sensitivity and during longer safe periods. Overall, this study is the first to suggest cognitive mechanisms underlying the greater avoidance behavior observed in healthy individuals with different anxiety vulnerabilities.

  3. Testing the role of reward and punishment sensitivity in avoidance behavior: a computational modeling approach.

    Science.gov (United States)

    Sheynin, Jony; Moustafa, Ahmed A; Beck, Kevin D; Servatius, Richard J; Myers, Catherine E

    2015-04-15

    Exaggerated avoidance behavior is a predominant symptom in all anxiety disorders and its degree often parallels the development and persistence of these conditions. Both human and non-human animal studies suggest that individual differences as well as various contextual cues may impact avoidance behavior. Specifically, we have recently shown that female sex and inhibited temperament, two anxiety vulnerability factors, are associated with greater duration and rate of the avoidance behavior, as demonstrated on a computer-based task closely related to common rodent avoidance paradigms. We have also demonstrated that avoidance is attenuated by the administration of explicit visual signals during "non-threat" periods (i.e., safety signals). Here, we use a reinforcement-learning network model to investigate the underlying mechanisms of these empirical findings, with a special focus on distinct reward and punishment sensitivities. Model simulations suggest that sex and inhibited temperament are associated with specific aspects of these sensitivities. Specifically, differences in relative sensitivity to reward and punishment might underlie the longer avoidance duration demonstrated by females, whereas higher sensitivity to punishment might underlie the higher avoidance rate demonstrated by inhibited individuals. Simulations also suggest that safety signals attenuate avoidance behavior by strengthening the competing approach response. Lastly, several predictions generated by the model suggest that extinction-based cognitive-behavioral therapies might benefit from the use of safety signals, especially if given to individuals with high reward sensitivity and during longer safe periods. Overall, this study is the first to suggest cognitive mechanisms underlying the greater avoidance behavior observed in healthy individuals with different anxiety vulnerabilities. PMID:25639540

  4. Os efeitos da aprendizagem psicomotora no controle das atividades de locomoção sobre obstáculos em crianças com deficiência da visão The effects of psychomotor learning on the control of locomotion during obstacle avoidance in children with low vision

    Directory of Open Access Journals (Sweden)

    Luiz Cezar dos Santos

    2007-12-01

    Full Text Available Considerando que a visão é um dos sistemas sensoriais mais importantes na locomoção pois fornece informação tanto do ambiente quanto da postura e dos movimentos corporais, este estudo analisou os efeitos de um programa de treinamento perceptivo-motor no controle das atividades de locomoção em seis crianças com deficiências da visão. Para tanto, realizou-se a avaliação da locomoção durante a transposição de obstáculos com alturas diferentes, utilizando-se indicadores qualitativos: postura / equilíbrio / direção / velocidade / contato visual com o obstáculo / erro na tarefa, e indicadores cinemáticos, obtidos por meio de filmagem (SVHS através do sistema Peak Motus (Versão 7.0 - Vicon Peak para medir: a distância do pé de apoio em relação ao obstáculo / a elevação máxima do joelho / a altura do pé em relação à altura do obstáculo. Os indicadores foram novamente avaliados após a realização do programa de treinamento, fornecendo evidências de sua contribuição positiva tanto na estratégia de aproximação quanto na estratégia de ultrapassagem dos obstáculos. Durante a aproximação, a velocidade da locomoção tornou-se mais constante e as passadas foram realizadas de forma mais retilínea. Durante a ultrapassagem, o número de toques no obstáculo diminuiu. Os resultados auxiliam na reflexão sobre a importância da aprendizagem psicomotora nos programas educacionais, particularmente na Educação Física Especial, como uma forma de contribuir para uma melhor qualidade de vida das crianças com baixa visão.Since vision is one of the most important sensory systems called upon for locomotion because it provides information not only about the environment, but also about posture and movement of corporal segments, this study analyzed the effects of a psychomotor training program on the control of locomotion with six children with low vision. Thus, an assessment of locomotion during obstacle avoidance with

  5. The global cost of eliminating avoidable blindness

    Directory of Open Access Journals (Sweden)

    Kirsten L Armstrong

    2012-01-01

    Full Text Available Aims : To complete an initial estimate of the global cost of eliminating avoidable blindness, including the investment required to build ongoing primary and secondary health care systems, as well as to eliminate the ′backlog′ of avoidable blindness. This analysis also seeks to understand and articulate where key data limitations lie. Materials and Methods : Data were collected in line with a global estimation approach, including separate costing frameworks for the primary and secondary care sectors, and the treatment of backlog. Results : The global direct health cost to eliminate avoidable blindness over a 10-year period from 2011 to 2020 is estimated at $632 billion per year (2009 US$. As countries already spend $592 billion per annum on eye health, this represents additional investment of $397.8 billion over 10 years, which is $40 billion per year or $5.80 per person for each year between 2010 and 2020. This is concentrated in high-income nations, which require 68% of the investment but comprise 16% of the world′s inhabitants. For all other regions, the additional investment required is $127 billion. Conclusions : This costing estimate has identified that low- and middle-income countries require less than half the additional investment compared with high-income nations. Low- and middle-income countries comprise the greater investment proportion in secondary care whereas high-income countries require the majority of investment into the primary sector. However, there is a need to improve sector data. Investment in better data will have positive flow-on effects for the eye health sector.

  6. Avoiding Lawsuits for Wage and Hour Violations.

    Science.gov (United States)

    Silberman, Cherie L

    2016-01-01

    Due to the highly technical language in the wage and hour laws and regulations, employers often find that they have unknowingly violated the Fair Labor Standards Act (FLSA). This can occur because employers have improperly classified an employee as exempt or because employers do not realize that certain time should be paid in full. Improperly classifying employees as exempt or failing to compensate nonexempt employees for all time worked can lead to costly lawsuits, audits, or enforcement actions by the Wage and Hour Division of the Department of Labor. This article discusses the most common FLSA exemptions and provides best practices to avoid liability under the FLSA.

  7. Guide to the collision avoidance rules

    CERN Document Server

    Cockcroft, A N

    2004-01-01

    A Guide to the Collision Avoidance Rules is the essential reference to the safe operation of all vessels at sea. Published continuously since 1965, this respected and expert guide is the classic text for all who need to, practically and legally, understand and comply with the Rules. This sixth edition incorporates all of the amendments to the International Regulations for Preventing Collisions at Sea which came into force in November 2003.The books sets out all of the Rules with clear explanation of their meaning, and gives detailed examples of how the rules have been used in practice

  8. Wireless vehicular networks for car collision avoidance

    CERN Document Server

    2013-01-01

    Wireless Vehicular Networks for Car Collision Avoidance focuses on the development of the ITS (Intelligent Transportation Systems) in order to minimize vehicular accidents. The book presents and analyses a range of concrete accident scenarios while examining the causes of vehicular collision and proposing countermeasures based on wireless vehicular networks. The book also describes the vehicular network standards and quality of service mechanisms focusing on improving critical dissemination of safety information. With recommendations on techniques and protocols to consider when improving road safety policies in order to minimize crashes and collision risks.

  9. How to avoid unnatural hierarchical thermal leptogenesis

    CERN Document Server

    Clarke, Jackson D

    2015-01-01

    A one-flavour naturalness argument suggests that the Type I seesaw model cannot naturally explain neutrino masses and the baryon asymmetry of the Universe via hierarchical thermal leptogenesis. We prove that there is no way to avoid this conclusion in a minimal three-flavour setup. We then comment on the simplest ways out. In particular, we focus on a resolution utilising a second Higgs doublet. Such models predict an automatically SM-like Higgs boson, (maximally) TeV-scale scalar states, and low- to intermediate-scale hierarchical leptogenesis with $10^3\\text{ GeV}\\lesssim M_{N_1}\\lesssim 10^7\\text{ GeV}$.

  10. Avoiding plagiarism: guidance for nursing students.

    Science.gov (United States)

    Price, Bob

    The pressures of study, diversity of source materials, past assumptions relating to good writing practice, ambiguous writing guidance on best practice and students' insecurity about their reasoning ability, can lead to plagiarism. With the use of source checking software, there is an increased chance that plagiarised work will be identified and investigated, and penalties given. In extreme cases, plagiarised work may be reported to the Nursing and Midwifery Council and professional as well as academic penalties may apply. This article provides information on how students can avoid plagiarism when preparing their coursework for submission.

  11. Understanding, Avoiding, and Managing Severe Filler Complications.

    Science.gov (United States)

    Rzany, Berthold; DeLorenzi, Claudio

    2015-11-01

    Any injectable filler may elicit moderate-to-severe adverse events, ranging from nodules to abscesses to vascular occlusion. Fortunately, severe adverse events are uncommon for the majority of fillers currently on the market. Because these are rare events, it is difficult to identify the relevant risk factors and to design the most efficacious treatment strategies. Poor aesthetic outcomes are far more common than severe adverse events. These in contrast should be easily avoidable by ensuring that colleagues receive proper training and follow best practices. PMID:26441099

  12. Avoiding plagiarism: guidance for nursing students.

    Science.gov (United States)

    Price, Bob

    The pressures of study, diversity of source materials, past assumptions relating to good writing practice, ambiguous writing guidance on best practice and students' insecurity about their reasoning ability, can lead to plagiarism. With the use of source checking software, there is an increased chance that plagiarised work will be identified and investigated, and penalties given. In extreme cases, plagiarised work may be reported to the Nursing and Midwifery Council and professional as well as academic penalties may apply. This article provides information on how students can avoid plagiarism when preparing their coursework for submission. PMID:24568425

  13. CORPORATE SOCIAL RESPONSIBILITY VERSUS TAX AVOIDANCE PRACTICES

    Directory of Open Access Journals (Sweden)

    Stoian Ciprian-Dumitru

    2012-07-01

    Full Text Available Worldwide crisis has made multinational companies that are engaged in corporate social responsibility actions to manage their businesses through the lens of various tax avoidance practices. The content of this paper is important due to the fact that tries to identify the impact in case of companies active in corporate social responsibility actions versus their tax structures orientation. Corporate social responsibility literature did not paid enough attention on the impact of the tax avoidance practices of companies. Tax, as a concept, brings in itself an important corporate financial impact with subsequent effects for the life of multiple citizens in countries where private entities are operating. Even though companies are usually expressing their ethical and responsible conduct in respect of the social environment, there are many cases when the business practices were not aligned with the declared corporate behavior. This paper seeks firstly to examine whether companies engaged in tax avoidance practices (ex. offshore tax havens consider that continue to act socially responsible. Secondly, the paper examines the influence on attending the stakeholders’ goals for those companies practicing tax avoidance and its implications on corporate social responsibility actions. Moreover, the paper focuses also on the aspects described before from the perspective of the corporate entities operating in Romania. This paper’s intention is to use and to develop the results of previous research carried out by Lutz Preus (University of London and, subsequently, by Senators Levin, Coleman and Obama in their “Stop Tax Haven Abuse Bill”. The implications and the objectives of this material are to highlight, to identify and to spot clearly the relations and the influences of the tax haven practices of corporations versus their undertaken social responsibility actions. Moreover, this paper brings a fresh perspective of this topic from the

  14. Avoiding the Somnolent Zone: Lessons from Singapore

    Science.gov (United States)

    Bathurst, Ralph

    2007-01-01

    As an experienced classroom teacher, the author was dismayed at what seemed a total lack of engagement by Singaporean theology students. To determine class dynamics, or lack thereof, the instructor discussed his situation with colleagues and investigated the nature of his students' preferred learning styles. Finding that his students were visual…

  15. Yuk! Peanut Butter Again: Avoiding Instructional Monotony.

    Science.gov (United States)

    Gunter, Mary Alice; Hotchkiss, Phyllis Riley

    1985-01-01

    This article presents a rationale for instructional variety based on the differences in the learning style of the students and on the objectives of the curriculum. A models of teaching approach for planning is described. A long-term professional development plan to implement teaching models for instructional variety is presented. (MT)

  16. The habenulo-raphe serotonergic circuit encodes an aversive expectation value essential for adaptive active avoidance of danger.

    Science.gov (United States)

    Amo, Ryunosuke; Fredes, Felipe; Kinoshita, Masae; Aoki, Ryo; Aizawa, Hidenori; Agetsuma, Masakazu; Aoki, Tazu; Shiraki, Toshiyuki; Kakinuma, Hisaya; Matsuda, Masaru; Yamazaki, Masako; Takahoko, Mikako; Tsuboi, Takashi; Higashijima, Shin-ichi; Miyasaka, Nobuhiko; Koide, Tetsuya; Yabuki, Yoichi; Yoshihara, Yoshihiro; Fukai, Tomoki; Okamoto, Hitoshi

    2014-12-01

    Anticipation of danger at first elicits panic in animals, but later it helps them to avoid the real threat adaptively. In zebrafish, as fish experience more and more danger, neurons in the ventral habenula (vHb) showed tonic increase in the activity to the presented cue and activated serotonergic neurons in the median raphe (MR). This neuronal activity could represent the expectation of a dangerous outcome and be used for comparison with a real outcome when the fish is learning how to escape from a dangerous to a safer environment. Indeed, inhibiting synaptic transmission from vHb to MR impaired adaptive avoidance learning, while panic behavior induced by classical fear conditioning remained intact. Furthermore, artificially triggering this negative outcome expectation signal by optogenetic stimulation of vHb neurons evoked place avoidance behavior. Thus, vHb-MR circuit is essential for representing the level of expected danger and behavioral programming to adaptively avoid potential hazard.

  17. Power mobility with collision avoidance for older adults: User, caregiver, and prescriber perspectives

    Directory of Open Access Journals (Sweden)

    Rosalie H. Wang, BSc (OT, PhD

    2013-12-01

    Full Text Available Collision avoidance technology has the capacity to facilitate safer mobility among older power mobility users with physical, sensory, and cognitive impairments, thus enabling independence for more users. Little is known about consumers’ perceptions of collision avoidance. This article draws on interviews (29 users, 5 caregivers, and 10 prescribers to examine views on design and utilization of this technology. Data analysis identified three themes: "useful situations or contexts," "technology design issues and real-life application," and "appropriateness of collision avoidance technology for a variety of users." Findings support ongoing development of collision avoidance for older adult users. The majority of participants supported the technology and felt that it might benefit current users and users with visual impairments, but might be unsuitable for people with significant cognitive impairments. Some participants voiced concerns regarding the risk for injury with power mobility use and some identified situations where collision avoidance might be beneficial (driving backward, avoiding dynamic obstacles, negotiating outdoor barriers, and learning power mobility use. Design issues include the need for context awareness, reliability, and user interface specifications. User desire to maintain driving autonomy supports development of collaboratively controlled systems. This research lays the groundwork for future development by illustrating consumer requirements for this technology.

  18. Hippocampus and two-way active avoidance conditioning: Contrasting effects of cytotoxic lesion and temporary inactivation.

    Science.gov (United States)

    Wang, Jia; Bast, Tobias; Wang, Yu-Cong; Zhang, Wei-Ning

    2015-12-01

    Hippocampal lesions tend to facilitate two-way active avoidance (2WAA) conditioning, where rats learn to cross to the opposite side of a conditioning chamber to avoid a tone-signaled footshock. This classical finding has been suggested to reflect that hippocampus-dependent place/context memory inhibits 2WAA (a crossing response to the opposite side is inhibited by the memory that this is the place where a shock was received on the previous trial). However, more recent research suggests other aspects of hippocampal function that may support 2WAA learning. More specifically, the ventral hippocampus has been shown to contribute to behavioral responses to aversive stimuli and to positively modulate the meso-accumbens dopamine system, whose activation has been implicated in 2WAA learning. Permanent hippocampal lesions may not reveal these contributions because, following complete and permanent loss of hippocampal output, other brain regions may mediate these processes or because deficits could be masked by lesion-induced extra-hippocampal changes, including an upregulation of accumbal dopamine transmission. Here, we re-examined the hippocampal role in 2WAA learning in Wistar rats, using permanent NMDA-induced neurotoxic lesions and temporary functional inhibition by muscimol or tetrodotoxin (TTX) infusion. Complete hippocampal lesions tended to facilitate 2WAA learning, whereas ventral (VH) or dorsal hippocampal (DH) lesions had no effect. In contrast, VH or DH muscimol or TTX infusions impaired 2WAA learning. Ventral infusions caused an immediate impairment, whereas after dorsal infusions rats showed intact 2WAA learning for 40-50 min, before a marked deficit emerged. These data show that functional inhibition of ventral hippocampus disrupts 2WAA learning, while the delayed impairment following dorsal infusions may reflect the time required for drug diffusion to ventral hippocampus. Overall, using temporary functional inhibition, our study shows that the ventral

  19. A learning object success story

    OpenAIRE

    Mason, R D; Pegler, C A; Weller, M J

    2005-01-01

    This paper outlines an approach to designing a course entirely in learning objects. It provides a theoretical basis for the design and then presents evaluation data from a master’s level course using this design. It also describes several re-uses of the learning objects on other courses and in different contexts. Each learning object is conceived as a whole learning experience, thus avoiding many of the problems associated with assembling components of disparate kinds.

  20. Avoidance of strobe lights by zooplankton

    Science.gov (United States)

    Hamel, Martin J.; Richards, Nathan S.; Brown, Michael L.; Chipps, Steven R.

    2010-01-01

    Underwater strobe lights can influence the behavior and distribution of fishes and are increasingly used as a technique to divert fish away from water intake structures on dams. However, few studies examine how strobe lights may affect organisms other than targeted species. To gain insight on strobe lighting effects on nontarget invertebrates, we investigated whether underwater strobe lights influence zooplankton distributions and abundance in Lake Oahe, South Dakota. Zooplankton were collected using vertical tows at 3 discrete distances from an underwater strobe light to quantify the influence of light intensity on zooplankton density. Samples were collected from 3 different depth ranges (0–10 m, 10–20 m and 20–30 m) at zooplankton sampled from 17 August to 15 September 2004. Night time zooplankton densities significantly decreased in surface waters when strobe lights were activated. Copepods exhibited the greatest avoidance patterns, while Daphnia avoidance varied throughout sampling depths. These results indicate that zooplankton display negative phototaxic behavior to strobe lights and that researchers must be cognizant of potential effects to the ecosystem such as altering predator–prey interactions or affecting zooplankton distribution and growth.

  1. Shape optimization of self-avoiding curves

    Science.gov (United States)

    Walker, Shawn W.

    2016-04-01

    This paper presents a softened notion of proximity (or self-avoidance) for curves. We then derive a sensitivity result, based on shape differential calculus, for the proximity. This is combined with a gradient-based optimization approach to compute three-dimensional, parameterized curves that minimize the sum of an elastic (bending) energy and a proximity energy that maintains self-avoidance by a penalization technique. Minimizers are computed by a sequential-quadratic-programming (SQP) method where the bending energy and proximity energy are approximated by a finite element method. We then apply this method to two problems. First, we simulate adsorbed polymer strands that are constrained to be bound to a surface and be (locally) inextensible. This is a basic model of semi-flexible polymers adsorbed onto a surface (a current topic in material science). Several examples of minimizing curve shapes on a variety of surfaces are shown. An advantage of the method is that it can be much faster than using molecular dynamics for simulating polymer strands on surfaces. Second, we apply our proximity penalization to the computation of ideal knots. We present a heuristic scheme, utilizing the SQP method above, for minimizing rope-length and apply it in the case of the trefoil knot. Applications of this method could be for generating good initial guesses to a more accurate (but expensive) knot-tightening algorithm.

  2. Collision avoidance for CTV: Requirements and capabilities

    Science.gov (United States)

    Nosek, Thomas P.

    Cargo transfer vehicle (CTV) operations near Space Station Freedom will require positive collision avoidance maneuver (CAM) capability to preclude any change of collision, even in the event of CTV failures. The requirements for CAM are discussed, and the CAM design approach and design of the Orbiting Maneuvering Vehicle (OMV) are reviewed; this design met requirements for OMV operation near the Space Station, provided a redundant collision avoidance maneuver capability. Significant portions of the OMV CAM design should be applicable to CTV. The key features of the OMV design are summarized and related to the CTV mission design to that of OMV's. CAM is a defined sequence of events executed by the CTV to place the vehicle in a safe position relative to a target such as the Space Station. CAM can be performed through software commands to the propulsion system, or through commands pre-stored in hardware. Various techniques for triggering CAM are considered, and the risks associated with CAM enable and execution in phases are considered. OMV CAM design features both hardware and software CAM capability, with analyses conducted to assess the ability to meet the collision-free requirement during all phases of the mission.

  3. Ship Collision Avoidance by Distributed Tabu Search

    Directory of Open Access Journals (Sweden)

    Dong-Gyun Kim

    2015-03-01

    Full Text Available More than 90% of world trade is transported by sea. The size and speed of ships is rapidly increasing in order to boost economic efficiency. If ships collide, the damage and cost can be astronomical. It is very difficult for officers to ascertain routes that will avoid collisions, especially when multiple ships travel the same waters. There are several ways to prevent ship collisions, such as lookouts, radar, and VHF radio. More advanced methodologies, such as ship domain, fuzzy theory, and genetic algorithm, have been proposed. These methods work well in one-on-one situations, but are more difficult to apply in multiple-ship situations. Therefore, we proposed the Distributed Local Search Algorithm (DLSA to avoid ship collisions as a precedent study. DLSA is a distributed algorithm in which multiple ships communicate with each other within a certain area. DLSA computes collision risk based on the information received from neighboring ships. However, DLSA suffers from Quasi-Local Minimum (QLM, which prevents a ship from changing course even when a collision risk arises. In our study, we developed the Distributed Tabu Search Algorithm (DTSA. DTSA uses a tabu list to escape from QLM that also exploits a modified cost function and enlarged domain of next-intended courses to increase its efficiency. We conducted experiments to compare the performance of DLSA and DTSA. The results showed that DTSA outperformed DLSA.

  4. Convective Weather Avoidance with Uncertain Weather Forecasts

    Science.gov (United States)

    Karahan, Sinan; Windhorst, Robert D.

    2009-01-01

    Convective weather events have a disruptive impact on air traffic both in terminal area and in en-route airspaces. In order to make sure that the national air transportation system is safe and efficient, it is essential to respond to convective weather events effectively. Traffic flow control initiatives in response to convective weather include ground delay, airborne delay, miles-in-trail restrictions as well as tactical and strategic rerouting. The rerouting initiatives can potentially increase traffic density and complexity in regions neighboring the convective weather activity. There is a need to perform rerouting in an intelligent and efficient way such that the disruptive effects of rerouting are minimized. An important area of research is to study the interaction of in-flight rerouting with traffic congestion or complexity and developing methods that quantitatively measure this interaction. Furthermore, it is necessary to find rerouting solutions that account for uncertainties in weather forecasts. These are important steps toward managing complexity during rerouting operations, and the paper is motivated by these research questions. An automated system is developed for rerouting air traffic in order to avoid convective weather regions during the 20- minute - 2-hour time horizon. Such a system is envisioned to work in concert with separation assurance (0 - 20-minute time horizon), and longer term air traffic management (2-hours and beyond) to provide a more comprehensive solution to complexity and safety management. In this study, weather is dynamic and uncertain; it is represented as regions of airspace that pilots are likely to avoid. Algorithms are implemented in an air traffic simulation environment to support the research study. The algorithms used are deterministic but periodically revise reroutes to account for weather forecast updates. In contrast to previous studies, in this study convective weather is represented as regions of airspace that pilots

  5. Cod avoidance by area regulations in Kattegat

    DEFF Research Database (Denmark)

    Eliasen, Søren Qvist

    2014-01-01

    and temporary area closures in Kattegat. The third section discusses the lessons learned in the light of implementation of the discard ban. The fourth section sums up the lessons learned; Regional measures of implementation of the discard ban should include all vessels with quota in the region to be regarded...... fair and the goals should be clear, not least when the descriptors of the Marine Strategy Framework Directive, which might be more intangible for the fishers, are part of the goal of the measures. If incentives created by the regulation are stable over at least a few years the fishers and fishers......’ organisations are more capable at being active partners in developing the systems that support the discard ban. An example from the examined initiatives are the outline of a fleet information system, providing the skipper with information about hotspots of unwanted species allowing him to make a better plan...

  6. Mars Rover Local Navigation And Hazard Avoidance

    Science.gov (United States)

    Wilcox, B. H.; Gennery, D. B.; Mishkin, A. H.

    1989-03-01

    A Mars rover sample return mission has been proposed for the late 1990's. Due to the long speed-of-light delays between Earth and Mars, some autonomy on the rover is highly desirable. JPL has been conducting research in two possible modes of rover operation, Computer-Aided Remote Driving and Semiautonomous Navigation. A recently-completed research program used a half-scale testbed vehicle to explore several of the concepts in semiautonomous navigation. A new, full-scale vehicle with all computational and power resources on-board will be used in the coming year to demonstrate relatively fast semiautonomous navigation. The computational and power requirements for Mars rover local navigation and hazard avoidance are discussed.

  7. Avoiding Quantum Chaos in Quantum Computation

    CERN Document Server

    Berman, G P; Izrailev, F M; Tsifrinovich, V I

    2001-01-01

    We study a one-dimensional chain of nuclear $1/2-$spins in an external time-dependent magnetic field. This model is considered as a possible candidate for experimental realization of quantum computation. According to the general theory of interacting particles, one of the most dangerous effects is quantum chaos which can destroy the stability of quantum operations. According to the standard viewpoint, the threshold for the onset of quantum chaos due to an interaction between spins (qubits) strongly decreases with an increase of the number of qubits. Contrary to this opinion, we show that the presence of a magnetic field gradient helps to avoid quantum chaos which turns out to disappear with an increase of the number of qubits. We give analytical estimates which explain this effect, together with numerical data supporting

  8. Collision Avoidance of Trains Using Arm7

    Directory of Open Access Journals (Sweden)

    Dr. K. R. R. Mohan Rao

    2015-11-01

    Full Text Available Railways are the popular mode of Transport in almost all major cities of the World. Railways are the most widely used and comfortable modes of transportation system. The major cause for railway accidents is collision of trains on the same track. The main aim of this anti collision system is to identify collision points and to report these error cases to main control room nearer to the station as well as grid control station. Majority of accidents occurred due to improper communication among the network between drivers and control room, due to wrong signaling, worst atmospheric condition, immediate change of route. The train driver doesn’t get proper information in time leading to hazardous situations. So this system by using zigbee protocol provides communication in between trains, which provide information or track id of one train to another train to avoid collision.

  9. Experiential Avoidance and Technological Addictions in Adolescents.

    Science.gov (United States)

    García-Oliva, Carlos; Piqueras, José A

    2016-06-01

    Background and aims This study focuses on the use of popular information and communication technologies (ICTs) by adolescents: the Internet, mobile phones, and video games. The relationship of ICT use and experiential avoidance (EA), a construct that has emerged as underlying and transdiagnostic to a wide variety of psychological problems, including behavioral addictions, is examined. EA refers to a self-regulatory strategy involving efforts to control or escape from negative stimuli such as thoughts, feelings, or sensations that generate strong distress. This strategy, which may be adaptive in the short term, is problematic if it becomes an inflexible pattern. Thus, the aim of this study was to explore whether EA patterns were associated with addictive or problematic use of ICT in adolescents. Methods A total of 317 students of the Spanish southeast between 12 and 18 years old were recruited to complete a questionnaire that included questions about general use of each ICTs, an experiential avoidance questionnaire, a brief inventory of the Big Five personality traits, and specific questionnaires on problematic use of the Internet, mobile phones, and video games. Results Correlation analysis and linear regression showed that EA largely explained results regarding the addictive use of the Internet, mobile phones, and video games, but not in the same way. As regards gender, boys showed a more problematic use of video games than girls. Concerning personality factors, conscientiousness was related to all addictive behaviors. Discussion and conclusions We conclude that EA is an important construct that should be considered in future models that attempt to explain addictive behaviors. PMID:27363463

  10. Effects of psychotropic agents on extinction of lever-press avoidance in a rat model of anxiety vulnerability

    Directory of Open Access Journals (Sweden)

    Xilu eJiao

    2014-09-01

    Full Text Available Avoidance and its perseveration represent key features of anxiety disorders. Both pharmacological and behavioral approaches (i.e. anxiolytics and extinction therapy have been utilized to modulate avoidance behavior in patients. However, the outcome has not always been desirable. Part of the reason is attributed to the diverse neuropathology of anxiety disorders. Here, we investigated the effect of psychotropic drugs that target various monoamine systems on extinction of avoidance behavior using lever-press avoidance task. Here we used the Wistar-Kyoto (WKY rat, a unique rat model that exhibits facilitated avoidance and extinction resistance along with malfunction of the dopamine (DA system. Sprague Dawley (SD and WKY rats were trained to acquire lever-press avoidance. WKY rats acquired avoidance faster and to a higher level compared to SD rats. During pharmacological treatment, bupropion, and desipramine significantly reduced avoidance response selectively in WKY rats. However, after the discontinuation of drug treatment, only those WKY rats that were previously treated with desipramine exhibited lower avoidance response compared to the control group. In contrast, none of the psychotropic drugs facilitated avoidance extinction in SD rats. Instead, desipramine impaired avoidance extinction and increased non-reinforced response in SD rats. Interestingly, paroxetine, a widely used antidepressant and anxiolytic, exhibited the weakest effect in WKY rats and no effects at all in SD rats. Thus, our data suggest that malfunctions in brain catecholamine system could be one of the underlying etiologies of anxiety-like behavior, particularly avoidance perseveration. Pharmacological manipulation targeting DA and norepinephrine is more effective to facilitate extinction learning in this strain. The data from the present study may shed light on new pharmacological approaches to treat patients with anxiety disorders who are not responding to serotonin re

  11. Neural mechanisms of context-dependent processing of CO2 avoidance behavior in fruit flies.

    Science.gov (United States)

    Siju, K P; Bräcker, Lasse B; Grunwald Kadow, I C

    2014-01-01

    The fruit fly, Drosophila melanogaster, innately avoids even low levels of CO2. CO2 is part of the so-called Drosophila stress odor produced by stressed flies, but also a byproduct of fermenting fruit, a main food source, making the strong avoidance behavior somewhat surprising. Therefore, we addressed whether feeding states might influence the fly's behavior and processing of CO2. In a recent report, we showed that this innate behavior is differentially processed and modified according to the feeding state of the fly. Interestingly, we found that hungry flies require the function of the mushroom body, a higher brain center required for olfactory learning and memory, but thought to be dispensable for innate olfactory behaviors. In addition, we anatomically and functionally characterized a novel bilateral projection neuron connecting the CO2 sensory input to the mushroom body. This neuron was essential for processing of CO2 in the starved fly but not in the fed fly. In this Extra View article, we provide evidence for the potential involvement of the neuromodulator dopamine in state-dependent CO2 avoidance behavior. Taken together, our work demonstrates that CO2 avoidance behavior is mediated by alternative neural pathways in a context-dependent manner. Furthermore, it shows that the mushroom body is not only involved in processing of learned olfactory behavior, as previously suggested, but also in context-dependent innate olfaction. PMID:25483251

  12. Decoding an olfactory mechanism of kin recognition and inbreeding avoidance in a primate

    OpenAIRE

    Charpentier Marie JE; Boulet Marylène; Drea Christine M

    2009-01-01

    Abstract Background Like other vertebrates, primates recognize their relatives, primarily to minimize inbreeding, but also to facilitate nepotism. Although associative, social learning is typically credited for discrimination of familiar kin, discrimination of unfamiliar kin remains unexplained. As sex-biased dispersal in long-lived species cannot consistently prevent encounters between unfamiliar kin, inbreeding remains a threat and mechanisms to avoid it beg explanation. Using a molecular a...

  13. Avoidance orientation moderates the effect of threatening messages

    NARCIS (Netherlands)

    Riet, van 't J.P.; Ruiter, R.A.C.; Vries, de H.

    2012-01-01

    This study investigated the influence of individual differences in people's dispositional avoidance orientation on the persuasive effects of low- and high-threat messages promoting moderate drinking. First, participents (N = 99) individual differences in avoidance orientation were assessed, after wh

  14. [What type of avoidance for peanut allergic children?].

    Science.gov (United States)

    Feuillet-Dassonval, C; Agne, P-S-A; Rancé, F; Bidat, E

    2006-09-01

    We analyzed, from the literature, the balance benefit/risk of a strict avoidance of peanut in children with peanut allergy. The benefits of a strict avoidance diet seem limited: reactions to the low doses and to the peanut oil refined are rare and most often slight. It is not proven that a strict avoidance facilitates the cure of allergy. On the other hand, strict avoidance could induce a worsening of allergy, with deterioration of quality of life, creation of food neophobia. In case of cure of allergy, it is difficult to normalize the diet after a strict avoidance. Outside of the rare sensitive patients to a very low dose of peanut, for which a strict avoidance is counseled, the report benefits risk is in favor of the prescription of adapted avoidance to the eliciting dose. For the majority of the peanut allergic children, it seems to us that the avoidance can and must be limited to the non hidden peanut. PMID:16828543

  15. US Forest Service Aerial Fire Retardant Hydrographic Avoidance Areas: Aquatic

    Data.gov (United States)

    US Forest Service, Department of Agriculture — A map services on the www depicting aerial retardant avoidance areas for hydrographic feature data. Aerial retardant avoidance area for hydrographic feature data...

  16. Conjunctions and Collision Avoidance with Electrodynamic Tethers

    Science.gov (United States)

    Levin, E.

    2013-09-01

    Electrodynamic propulsion technology is currently in development by NASA, ESA, and JAXA for the purpose of affordable removal of large debris objects from LEO. At the same time, the Naval Research Laboratory is preparing a 3U CubeSat with a 1-km electrodynamic tether for a flight demonstration of electrodynamic propulsion. This type of propulsion does not require fuel. The electrodynamic thrust is the Lorentz force acting on the electric current in a long conductor (tether) in the geomagnetic field. Electrons are collected from the ambient plasma on one end and emitted back into the plasma from the other end. The electric current loop is closed through the ionosphere, as demonstrated in two previous flights. The vehicle is solar powered. To support safe navigation of electrodynamic tethers, proper conjunction analysis and collision avoidance strategies are needed. The typical lengths of electrodynamic tethers for near-term applications are measured in kilometers, and the conjunction geometry is very different from the geometry of conjunctions between compact objects. It is commonly thought that the collision cross-section in a conjunction between a tether and a compact object is represented by the product of the tether length and the size of the object. However, rigorous analysis shows that this is not the case, and that the above assumption leads to grossly overestimated collision probabilities. The paper will present the results of a detailed mathematical analysis of the conjunction geometry and collision probabilities in close approaches between electrodynamic tethers and compact objects, such as satellites, rocket bodies, and debris fragments. Electrodynamic spacecraft will not require fuel, and therefore, can thrust constantly. Their orbit transfers can take many days, but can result in major orbit changes, including large rotations of the orbital plane, both in the inclination and the node. During these orbit transfers, the electrodynamic spacecraft will

  17. Unobserved Tax Avoidance and the Tax Elasticity of FDI

    OpenAIRE

    Egger, Peter; Merlo, Valeria; Wamser, Georg

    2014-01-01

    This paper investigates the tax responsiveness of multinational firms’ investment decisions in foreign countries, distinguishing firms that are able to avoid taxes (avoiders) from those that are not (non-avoiders). From a theoretical point of view, the tax responsiveness of firms crucially depends on this distinction. Empirically, however, a firm’s ability to avoid profit taxes is inherently unobservable to the researcher. To address this problem, we use a finite mixture modeling approach whi...

  18. Passive and active place avoidance as a tool of spatial memory research in rats.

    Science.gov (United States)

    Cimadevilla, J M; Kaminsky, Y; Fenton, A; Bures, J

    2000-10-30

    A modified model of the arena described by Bures et al. (Bures J, Fenton AA, Kaminsky Y, Zinyuk L. Place cells and place navigation, Proc. Natl. Acad. Sci. USA. 1997a;94:343-350) was applied to the place learning of adult male rats in two different avoidance paradigms. In the passive avoidance task rats exploring a stationary circular arena had to avoid a 60 degrees sector entering of which was punished by mild footshocks. Intramaze as well as extramaze cues could be used for adequate solution of this task. In the active avoidance paradigm rats were trained to avoid a room frame defined sector (e.g. North-East) of a slowly rotating arena the movement of which forced the animals to rely on extramaze cues and to ignore intramaze information. Rats had to find an active solution of the task since otherwise they were passively transported into the room frame defined punished zone. The suitability of these tasks for testing spatial abilities of rats is discussed. PMID:11040412

  19. Effects of vasopressin on active and passive avoidance behavior

    NARCIS (Netherlands)

    Bohus, B.; Ader, R.; Wied, D. de

    1972-01-01

    Male rats were trained in an active avoidance and/or a “step-through” type of passive avoidance situation. Lysine vasopressin administration resulted in resistance to extinction of active avoidance behavior if it was injected 1 hr prior to the third and final acquisition session; peptide treatment 6

  20. Social anxiety predicts avoidance behaviour in virtual encounters

    NARCIS (Netherlands)

    Rinck, M.; Rörtgen, T.; Lange, W.G.; Dotsch, R.; Wigboldus, D.H.J.; Becker, E.S.

    2010-01-01

    Avoidant behaviour is critical in social anxiety and social phobia, being a major factor in the maintenance of anxiety. However, almost all previous studies of social avoidance were restricted to using self-reports for the study of intentional aspects of avoidance. In contrast, the current study use

  1. 14 CFR 121.356 - Collision avoidance system.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Collision avoidance system. 121.356 Section... Collision avoidance system. Effective January 1, 2005, any airplane you operate under this part must be equipped and operated according to the following table: Collision Avoidance Systems If you operate...

  2. Effects of optimism on creativity under approach and avoidance motivation

    NARCIS (Netherlands)

    Icekson, Tamar; Roskes, Marieke; Moran, Simone

    2014-01-01

    Focusing on avoiding failure or negative outcomes (avoidance motivation) can undermine creativity, due to cognitive (e.g., threat appraisals), affective (e.g., anxiety), and volitional processes (e.g., low intrinsic motivation). This can be problematic for people who are avoidance motivated by natur

  3. 14 CFR 129.18 - Collision avoidance system.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Collision avoidance system. 129.18 Section... § 129.18 Collision avoidance system. Effective January 1, 2005, any airplane you, as a foreign air... Avoidance Systems If you operate in the United States any . . . Then you must operate that airplane with:...

  4. 14 CFR 437.65 - Collision avoidance analysis.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Collision avoidance analysis. 437.65..., DEPARTMENT OF TRANSPORTATION LICENSING EXPERIMENTAL PERMITS Safety Requirements § 437.65 Collision avoidance... permittee must obtain a collision avoidance analysis from United States Strategic Command. (b) The...

  5. 14 CFR 417.231 - Collision avoidance analysis.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Collision avoidance analysis. 417.231..., DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH SAFETY Flight Safety Analysis § 417.231 Collision avoidance analysis. (a) General. A flight safety analysis must include a collision avoidance analysis...

  6. 20 CFR 606.23 - Avoidance of tax credit reduction.

    Science.gov (United States)

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Avoidance of tax credit reduction. 606.23... Tax Credit Reduction § 606.23 Avoidance of tax credit reduction. (a) Applicability. Subsection (g) of... receipts and benefit outlays under the law in effect for the year for which avoidance is requested, as...

  7. 20 CFR 606.24 - Application for avoidance.

    Science.gov (United States)

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Application for avoidance. 606.24 Section 606... Credit Reduction § 606.24 Application for avoidance. (a) Application. (1) The Governor of the State shall... respect to which a State requests avoidance of tax credit reduction. The Governor is required to...

  8. 50 CFR 600.510 - Gear avoidance and disposal.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Gear avoidance and disposal. 600.510 Section 600.510 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND... Gear avoidance and disposal. (a) Vessel and gear avoidance. (1) FFV's arriving on fishing grounds...

  9. 78 FR 35262 - Detection and Avoidance of Counterfeit Electronic Parts

    Science.gov (United States)

    2013-06-12

    ... Defense Acquisition Regulations System Detection and Avoidance of Counterfeit Electronic Parts AGENCY... and the private sector regarding the electronic parts detection and avoidance coverage proposed to be... about the requirements for detection and avoidance of counterfeit electronic parts in DoD contracts....

  10. Deforestation, leakage and avoided deforestation policies: a spatial analysis

    OpenAIRE

    DELACOTE, Philippe; Elizabeth J. Z. Robinson; Roussel, Sebastien

    2015-01-01

    This paper analyses the impact of several avoided deforestation policies within a patchy forested landscape. Central is the idea that deforestation choices in one area influence deforestation decisions in nearby patches. We explore the interplay between forest landscapes comprising heterogeneous patches, localised spatial displacement, and avoided deforestation policies. Avoided deforestation policies at a landscape level are respectively: two Payments for Environmental Services (PES) policie...

  11. 47 CFR 51.609 - Determination of avoided retail costs.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Determination of avoided retail costs. 51.609... (CONTINUED) INTERCONNECTION Resale § 51.609 Determination of avoided retail costs. (a) Except as provided in § 51.611, the amount of avoided retail costs shall be determined on the basis of a cost study...

  12. Involvement of the insular cortex in regulating glucocorticoid effects on memory consolidation of inhibitory avoidance training

    Directory of Open Access Journals (Sweden)

    Raquel eFornari

    2012-03-01

    Full Text Available Glucocorticoids are known to enhance the consolidation of memory of emotionally arousing experiences by acting upon a network of interconnected brain regions. Although animal studies typically do not consider the insular cortex (IC to be part of this network, the present findings indicate that the IC is importantly involved in regulating glucocorticoid effects on memory consolidation of emotionally arousing inhibitory avoidance training. The specific glucocorticoid receptor agonist RU 28362 (3 or 10 ng in 0.5 l infused bilaterally into the IC of male Sprague-Dawley rats immediately after one-trial inhibitory avoidance training dose-dependently enhanced 48-h retention performance. Moreover, training on the inhibitory avoidance task increased neuronal activity of the IC, as assessed by an increased number of cells expressing immunoreactivity for phosphorylated extracellular signal-regulated kinase 1/2 (pERK1/2. However, systemic administration of a memory-enhancing dose of corticosterone (1 mg/kg after inhibitory avoidance training rapidly reduced the number of pERK1/2-positive cells in the IC, suggesting that glucocorticoid administration reduces overall neuronal activity of the IC. To investigate which components of the inhibitory avoidance training experience were influenced by the intra-IC glucocorticoid administration, in the last experiment rats were trained on a modified inhibitory avoidance task in which context exposure and footshock training occur on two sequential days. RU 28362 administration into the IC enhanced later retention when infused immediately after either the context or footshock training. Thus, these findings indicate that the IC mediates glucocorticoid effects on the consolidation of memory of different components of inhibitory avoidance training and suggest that the IC might be an important element of the rodent brain network involved in emotional regulation of learning and memory.

  13. Cybernetic Service-Learning Course Development: Lessons Learned

    Science.gov (United States)

    Marx, Jonathan I.; Miller, Lee Q.

    2009-01-01

    Although the title of the course, Combating Loneliness among Older People in Contemporary Society, states a clear goal, our service-learning class was shaped by five guiding parameters. By avoiding certain things, we allowed the course to self-organize and evolve into a learning experience beyond the one originally envisioned. This paper…

  14. Avoiding sexual harassment liability in veterinary practices.

    Science.gov (United States)

    Lacroix, C A; Wilson, J F

    1996-05-15

    Harassment based on gender violates the rule of workplace equality established by Title VII of the Civil Rights Act and enforced by the EEOC. In 1986, the US Supreme Court, in Meritor Savings Bank v Vinson, established the criteria that must be met for a claim of hostile environment sexual harassment to be considered valid. Plaintiffs must show that they were subjected to conduct based on their gender, that it was unwelcome, and that it was severe and pervasive enough to alter their condition of employment, resulting in an abusive working environment. There have been few sexual harassment cases involving veterinary professionals, and it is our goal to help keep the number of filed actions to a minimum. The most effective way to avoid hostile environment sexual harassment claims is to confront the issue openly and to adopt a sexual harassment policy for the practice. When it comes to sexual harassment, an ounce of prevention is unquestionably worth a pound of cure. PMID:8641947

  15. Can low metallicity binaries avoid merging?

    CERN Document Server

    de Mink, S E; Pols, O R

    2007-01-01

    Rapid mass transfer in a binary system can drive the accreting star out of thermal equilibrium, causing it to expand. This can lead to a contact system, strong mass loss from the system and possibly merging of the two stars. In low metallicity stars the timescale for heat transport is shorter due to the lower opacity. The accreting star can therefore restore thermal equilibrium more quickly and possibly avoid contact. We investigate the effect of accretion onto main sequence stars with radiative envelopes with different metallicities. We find that a low metallicity (Z<0.001), 4 solar mass star can endure a 10 to 30 times higher accretion rate before it reaches a certain radius than a star at solar metallicity. This could imply that up to two times fewer systems come into contact during rapid mass transfer when we compare low metallicity. This factor is uncertain due to the unknown distribution of binary parameters and the dependence of the mass transfer timescale on metallicity. In a forthcoming paper we w...

  16. The amygdala: securing pleasure and avoiding pain

    Directory of Open Access Journals (Sweden)

    Anushka B P Fernando

    2013-12-01

    Full Text Available The amygdala has traditionally been associated with fear, mediating the impact of negative emotions on memory. However, this view does not fully encapsulate the function of the amygdala, nor the impact that processing in this structure has on the motivational limbic corticostriatal circuitry of which it is an important structure. Here we discuss the interactions between different amygdala nuclei with cortical and striatal regions involved in motivation; interconnections and parallel circuitries that have become increasingly understood in recent years. We review the evidence that the amygdala stores memories that allow initially motivationally neutral stimuli to become associated through pavlovian conditioning with motivationally relevant outcomes which, importantly, can be either appetitive (e.g. food or aversive (e.g. electric shock. We also consider how different psychological processes supported by the amygdala such as conditioned reinforcement and punishment, conditioned motivation and suppression, and conditioned approach and avoidance behavior, are not only psychologically but also neurobiologically dissociable, being mediated by distinct yet overlapping neural circuits within the limbic corticostriatal circuitry. Clearly the role of the amygdala goes beyond encoding aversive stimuli to also encode the appetitive, requiring an appreciation of the amygdala’s mediation of both appetitive and fearful behavior through diverse psychological processes.

  17. Genetic contributions to avoidance-based decisions: striatal D2 receptor polymorphisms.

    Science.gov (United States)

    Frank, M J; Hutchison, K

    2009-11-24

    Individuals differ in their tendencies to seek positive decision outcomes or to avoid negative ones. At the neurobiological level, our model suggests that phasic changes in dopamine support learning to reinforce good decisions via striatal D1 receptors, and to avoid maladaptive choices via striatal D2 receptors. Accordingly, in a previous study individual differences in positive and negative learning were strongly modulated by two genetic polymorphisms factors related to striatal D1 and D2 function, respectively. Nevertheless, whereas the role for dopamine in positive learning is relatively well accepted, that in learning to avoid negative outcomes is more controversial. Here we further explore D2-receptor-related genetic contributions to probabilistic avoidance in humans, in light of recent data showing that particular DRD2 polymorphisms are associated with functional modulation of receptor expression [Zhang Y, Bertolino A, Fazio L, Blasi G, Rampino A, Romano R, Lee M-LT, Xiao T, Papp A, Wang D, Sadée W (2007) Polymorphisms in human dopamine d2 receptor gene affect gene expression, splicing, and neuronal activity during working memory. Proc Natl Acad Sci U S A 104(51):20552-20557]. We find that a promoter polymorphism rs12364283 associated with transcription and D2 receptor density was strongly and selectively predictive of avoidance-based decisions. Two further polymorphisms (rs2283265 and rs1076560) associated with relatively reduced presynaptic relative to postsynaptic D2 receptor expression were predictive of relative impairments in negative compared to positive decisions. These previously undocumented effects of DRD2 polymorphisms were largely independent of those we reported previously for the C957T polymorphism (rs6277) associated with striatal D2 density. In contrast, effects of the commonly studied Taq1A polymorphism on reinforcement-based decisions were due to indirect association with C957T. Taken together these findings suggest multiple D2-dependent

  18. Acquisition and extinction of human avoidance behavior: Attenuating effect of safety signals and associations with anxiety vulnerabilities

    Directory of Open Access Journals (Sweden)

    Jony eSheynin

    2014-09-01

    Full Text Available While avoidance behavior is often an adaptive strategy, exaggerated avoidance can be detrimental and result in the development of psychopathologies, such as anxiety disorders. A large animal literature shows that the acquisition and extinction of avoidance behavior in rodents depends on individual differences (e.g., sex, strain and might be modulated by the presence of environmental cues. However, there is a dearth of such reports in human literature, mainly due to the lack of adequate experimental paradigms. In the current study, we employed a computer-based task, where participants control a spaceship and attempt to gain points by shooting an enemy spaceship that appears on the screen. Warning signals predict on-screen aversive events; the participants can learn a protective response to escape or avoid these events. This task has been recently used to reveal facilitated acquisition of avoidance behavior in individuals with anxiety vulnerability, due to female sex or inhibited personality. Here, we extended the task to include an extinction phase, and tested the effect of signals that appeared during safe periods. Healthy young adults (n=122 were randomly assigned to a testing condition with or without such signals. Results showed that the addition of safety signals during the acquisition phase impaired acquisition (in females and facilitated extinction of the avoidance behavior. We also replicated our recent finding of an association between female sex and longer avoidance duration and further showed that females continued to demonstrate more avoidance behavior even on extinction trials when the aversive events no longer occurred. This study is the first to show sex differences on the acquisition and extinction of human avoidance behavior and to demonstrate the role of safety signals in such behavior, highlighting the potential relevance of safety signals for cognitive therapies that focus on extinction learning to treat anxiety symptoms.

  19. Why Do Consumers Avoid Certain Brands? : A Study of Brand Avoidance Within the Swedish Cosmetics Industry

    OpenAIRE

    Vong, Amy; Hellberg, Anna; Melander, Joanna

    2016-01-01

    Background - As of today, the positive forms of consumer-brand relationships have been intensively researched, whereas its counterpart has attained far less attention. Whilst current literature is focused on increasing positive brand equity, the knowledge of negative brand equity is sparse. When the brand-consumer relationship is negatively affected and the brand equity is unfavourable, rejection of a specific brand, namely brand avoidance might occur. This may affect companies negatively if ...

  20. EDITORIAL AVOIDABLE MORTALITY OF SCIENTIFIC MANUSCRIPTS

    Directory of Open Access Journals (Sweden)

    Mauricio Palacios

    2010-06-01

    Full Text Available Colombia Médica publishes 64% of the original research articles submitted to editorial process, which highlights the rigor of the editorial review system; while at the same time, generating a reflection on the causes for rejecting material submitted for publication as an input for the Journal’s collaborators.The review of the file of articles rejected by the Journal leads us to arbitrarily discriminating the causes for rejecting scientific documents into two groups: A first group we will call «lost causes», which centers on the lack of ethical evaluation, research design flaws, and plagiarism. And the second group, «manuscripts with avoidable rejection», which includes deficiencies in following the editorial guidelines for authors, inadequate writing, and delays by authors in submitting answers to observations raised during an initial evaluation. Documents classifying in the latter group could have had an opportunity with a bit of joint effort between the authors and the editorial board; and in all cases, by correcting errors and seeking support from, among others, expert consultants, these could, potentially, be revived by submitting them to a journal with a lower impact than that in which they were rejected.Among the reasons for the lost causes, we find that faults in the structure of institutional research take up considerable space. Institutions considering scientific production as one of their assets, must invest on the conformation and growth of an ethics committee on research that reasonably provides researchers with social, environmental, and ethical reflection elements to enrich research proposals. With bioethics foundations, Colombian and international norms do not consider other forms of ethical evaluation of the projects, and; consequently, neither does the Editorial Committee. Furthermore, anyone seeking to conduct clinical trials must register the entity in any of the international data bases that permit inputting the

  1. EDITORIAL AVOIDABLE MORTALITY OF SCIENTIFIC MANUSCRIPTS

    Directory of Open Access Journals (Sweden)

    Mauricio Palacios

    2010-06-01

    Full Text Available Colombia Médica publishes 64% of the original research articles submitted to editorial process, which highlights the rigor of the editorial review system; while at the same time, generating a reflection on the causes for rejecting material submitted for publication as an input for the Journal’s collaborators. The review of the file of articles rejected by the Journal leads us to arbitrarily discriminating the causes for rejecting scientific documents into two groups: A first group we will call «lost causes», which centers on the lack of ethical evaluation, research design flaws, and plagiarism. And the second group, «manuscripts with avoidable rejection», which includes deficiencies in following the editorial guidelines for authors, inadequate writing, and delays by authors in submitting answers to observations raised during an initial evaluation. Documents classifying in the latter group could have had an opportunity with a bit of joint effort between the authors and the editorial board; and in all cases, by correcting errors and seeking support from, among others, expert consultants, these could, potentially, be revived by submitting them to a journal with a lower impact than that in which they were rejected. Among the reasons for the lost causes, we find that faults in the structure of institutional research take up considerable space. Institutions considering scientific production as one of their assets, must invest on the conformation and growth of an ethics committee on research that reasonably provides researchers with social, environmental, and ethical reflection elements to enrich research proposals. With bioethics foundations, Colombian and international norms do not consider other forms of ethical evaluation of the projects, and; consequently, neither does the Editorial Committee. Furthermore, anyone seeking to conduct clinical trials must register the entity in any of the international data bases that permit inputting the

  2. Learning about policy learning. Reflections on the European Employment Strategy

    OpenAIRE

    Miriam Hartlapp

    2009-01-01

    The concept of policy learning has been attracting increasing attention in the political science literature, notably in the many publications on the Open Method of Coordination (OMC). However, much research faces fundamental methodological problems regarding the mode of functioning and extent of policy learning. This paper shows that these problems can be avoided if we take a closer look at the potential of the OMC instruments to stimulate learning. The paper differentiates between three type...

  3. The Role of Muscarinic and Nicotinic Cholinergic Neurotransmission in Aversive Conditioning: Comparing Pavlovian Fear Conditioning and Inhibitory Avoidance

    Science.gov (United States)

    Tinsley, Matthew R.; Quinn, Jennifer J.; Fanselow, Michael S.

    2004-01-01

    Aversive conditioning is an ideal model for studying cholinergic effects on the processes of learning and memory for several reasons. First, deficits produced by selective lesions of the anatomical structures shown to be critical for Pavlovian fear conditioning and inhibitory avoidance (such as the amygdala and hippocampus) resemble those deficits…

  4. Environmental Restoration Disposal Facility Lessons Learned

    Energy Technology Data Exchange (ETDEWEB)

    Caulfield, R.

    2012-07-12

    The purpose of lessons learned is to identify insight gained during a project – successes or failures – that can be applied on future projects. Lessons learned can contribute to the overall success of a project by building on approaches that have worked well and avoiding previous mistakes. Below are examples of lessons learned during ERDF’s ARRA-funded expansion project.

  5. The Competitive Strategy of Mutual Learning.

    Science.gov (United States)

    Kelner, Stephen P.; Slavin, Lois

    1998-01-01

    Defines and discusses mutual learning in organizations. Suggests that the idea of people and companies sharing knowledge is becoming a competitive strategy because mutual learning enables executives and employees to increase their capacity to work together, accelerate organizational learning, and avoid mistakes. (JOW)

  6. Development of Tactical Lightning Avoidance Product for Terminal Weather Support

    Science.gov (United States)

    Yoshikawa, E.; Yoshida, S.; Adachi, T.; Kusunoki, K.; Ushio, T.

    2015-12-01

    Aircraft initiated or intercepted lightning is one of significant issues for civilian flight operation in Japan. It is much less possible than the past that lightning strikes cause fatal aircraft accidents thanks to both of certifications of aircraft design for lightning strikes and many of weather supports for aircraft operation. However, hundreds of lightning strikes to aircrafts have still been reported in each recent year in Japan, and airlines have been forced to delay or cancel most of those flights and to cost several hundred millions of yen for repair. Especially, lightning discharges during winter in the coastal area of the Sea of Japan frequently cause heavy damages on aircrafts due to their large charge transfer. It is important in actual aircraft operation that observed meteorological parameters are converted to decision-making information. Otherwise, pilots, controllers, or operators need to learn meteorology as much as weather experts, and to owe hard work load to interpret observed meteorological data to their risk. Ideally, it is desired to automatically provide them with predicted operation risk, for example, delay time, possibility of flight cancellation, and repair cost caused by lightning.Our research group has just started development of tactical lightning avoidance product, where a risk index of an aircraft operation due to lightning is calculated mainly from three novel observation devices: The phased array weather radar has potential to detect thunderstorms in their early stage due to the high volume scan rate of 10 - 30 sec. A lightning mapping system, such as Broadband Observation network for Lightning and Thunderstorm, indicates electrical structure inside clouds in concert with a co-located radar data. Aircraft sounding and real-time data downlink, especially high-frequency data provided by Secondary Surveillance Radar mode S, gives in-situ measurements of wind and temperature. Especially the in-situ temperature data can indicate

  7. Towards better patient care: drugs to avoid.

    Science.gov (United States)

    2013-04-01

    Common sense dictates that one should choose tried and tested drugs with proven, concrete benefits that outweigh their adverse effects. Many new drugs are approved each year, often despite a lack of solid evidence that they are any better than existing treatments. Worse, some are approved despite being less effective or more harmful than current options. Massive promotion is used to ensure that such drugs achieve a positive image in the eyes of healthcare professionals and patients. Renowned "opinion leaders" intervene in their favour at conferences and in specialist media, and their opinions are further propagated by specialists in the field. Finally, campaigns in the lay media are used to highlight the target illness, encouraging patients to request a prescription. New data sometimes show that older, initially promising drugs are less effective or more harmful than first thought. For all these reasons, many drugs that are now present on the market are more harmful than beneficial and should be avoided. Unfortunately, negative assessment data and warnings are often drowned in the flood of promotion and advertising. Front-line healthcare professionals who are determined to act in their patients' best interests can find themselves swimming against a tide of specialist opinion, marketing authorisation, and reimbursement decisions. By leaving drugs that are more harmful than beneficial on the market and contenting themselves with simple half-measures, healthcare authorities are failing in their duty to protect patients. Prescrire, a journal funded solely by its subscribers, does not seek to do the work of health authorities, and does not have the means to do so. Prescrire's goal is simply to help healthcare professionals provide better care. The following text lists the principal drugs that we consider more harmful than beneficial, based on our reviews published between 2010 and 2012 in our French edition. These drugs should not be used. Patients and healthcare

  8. Towards better patient care: drugs to avoid.

    Science.gov (United States)

    2013-04-01

    Common sense dictates that one should choose tried and tested drugs with proven, concrete benefits that outweigh their adverse effects. Many new drugs are approved each year, often despite a lack of solid evidence that they are any better than existing treatments. Worse, some are approved despite being less effective or more harmful than current options. Massive promotion is used to ensure that such drugs achieve a positive image in the eyes of healthcare professionals and patients. Renowned "opinion leaders" intervene in their favour at conferences and in specialist media, and their opinions are further propagated by specialists in the field. Finally, campaigns in the lay media are used to highlight the target illness, encouraging patients to request a prescription. New data sometimes show that older, initially promising drugs are less effective or more harmful than first thought. For all these reasons, many drugs that are now present on the market are more harmful than beneficial and should be avoided. Unfortunately, negative assessment data and warnings are often drowned in the flood of promotion and advertising. Front-line healthcare professionals who are determined to act in their patients' best interests can find themselves swimming against a tide of specialist opinion, marketing authorisation, and reimbursement decisions. By leaving drugs that are more harmful than beneficial on the market and contenting themselves with simple half-measures, healthcare authorities are failing in their duty to protect patients. Prescrire, a journal funded solely by its subscribers, does not seek to do the work of health authorities, and does not have the means to do so. Prescrire's goal is simply to help healthcare professionals provide better care. The following text lists the principal drugs that we consider more harmful than beneficial, based on our reviews published between 2010 and 2012 in our French edition. These drugs should not be used. Patients and healthcare

  9. Adolescents' approach-avoidance behaviour in the context of pain.

    Science.gov (United States)

    Fisher, Emma; Keogh, Edmund; Eccleston, Christopher

    2016-02-01

    Adolescents who experience pain often face competing goals and have to choose whether to approach (confront) or avoid pain. This study investigates the decisions adolescents make when their pain conflicts with a valued goal. Adolescents between the ages of 15 and 18 years (N = 170) completed questionnaires on general and pain-specific anxiety, courage, and dispositional avoidance. Adolescents were presented with 16 vignettes (8 high pain intensity, 8 low pain intensity), which described pain conflicting with a goal (eg, doing well at school, seeing friends). Adolescents rated goals for importance and reported how likely they would be to approach or avoid each pain. Adolescents were more likely to avoid and were more fearful of high pain intensity than low pain intensity vignettes. Pain anxiety predicted higher levels of avoidance for both pain intensities. General anxiety was not a significant predictor of avoidance for either pain intensity. Goal importance promoted approach of goals, but only when pain was described as intense. However, pain anxiety predicted avoidance beyond the importance of goals for high pain intensity vignettes. In addition, we compared approach-avoidance of adolescents with and without chronic pain; analyses revealed no differences in approach-avoidance behaviour. We also found that behavioural endurance was predictive of approach and dispositional avoidance predicted higher avoidance, but courage was not predictive of behaviour in this task. We adopt a motivational perspective when interpreting the findings and consider whether the fear-avoidance model should be extended to include the function of avoidance or approach in the pursuit of a desired goal.

  10. Self-Assessment of the Use of Plagiarism Avoiding Techniques to Create Ethical Scholarship Among Research Students

    Directory of Open Access Journals (Sweden)

    Saeed Ahmad

    2015-11-01

    Full Text Available The use of plagiarism avoiding techniques can be helpful to maintain academic integrity, a better learning environment and intellectual honesty. This explored the use of plagiarism avoiding techniques for creating ethical scholarship among research students. It also measured the association between the frequency of using plagiarism avoiding techniques and the satisfaction about knowledge of plagiarism. Data were collected from seven universities through an online self-structured questionnaire. Ordinal logistic regression analysis was used to explore the variance. The association between the frequency of using plagiarism avoiding techniques and satisfaction about knowledge of plagiarism was indicated. Differences were also found on the basis of gender, discipline, level and stage of study.

  11. Avoidant decision making in social anxiety: the interaction of angry faces and emotional responses.

    Science.gov (United States)

    Pittig, Andre; Pawlikowski, Mirko; Craske, Michelle G; Alpers, Georg W

    2014-01-01

    Recent research indicates that angry facial expressions are preferentially processed and may facilitate automatic avoidance response, especially in socially anxious individuals. However, few studies have examined whether this bias also expresses itself in more complex cognitive processes and behavior such as decision making. We recently introduced a variation of the Iowa Gambling Task which allowed us to document the influence of task-irrelevant emotional cues on rational decision making. The present study used a modified gambling task to investigate the impact of angry facial expressions on decision making in 38 individuals with a wide range of social anxiety. Participants were to find out which choices were (dis-) advantageous to maximize overall gain. To create a decision conflict between approach of reward and avoidance of fear-relevant angry faces, advantageous choices were associated with angry facial expressions, whereas disadvantageous choices were associated with happy facial expressions. Results indicated that higher social avoidance predicted less advantageous decisions in the beginning of the task, i.e., when contingencies were still uncertain. Interactions with specific skin conductance responses further clarified that this initial avoidance only occurred in combination with elevated responses before choosing an angry facial expressions. In addition, an interaction between high trait anxiety and elevated responses to early losses predicted faster learning of an advantageous strategy. These effects were independent of intelligence, general risky decision-making, self-reported state anxiety, and depression. Thus, socially avoidant individuals who respond emotionally to angry facial expressions are more likely to show avoidance of these faces under uncertainty. This novel laboratory paradigm may be an appropriate analog for central features of social anxiety. PMID:25324792

  12. Avoidant decision making in social anxiety: The interaction of angry faces and emotional responses

    Directory of Open Access Journals (Sweden)

    Andre ePittig

    2014-09-01

    Full Text Available Recent research indicates that angry facial expressions are preferentially processed and may facilitate automatic avoidance response, especially in socially anxious individuals. However, few studies have examined whether this bias also expresses itself in more complex cognitive processes and behavior such as decision making. We recently introduced a variation of the Iowa Gambling Task which allowed us to document the influence of task-irrelevant emotional cues on rational decision making. The present study used a modified gambling task to investigate the impact of angry facial expressions on decision making in 38 individuals with a wide range of social anxiety. Participants were to find out which choices were (dis- advantageous to maximize overall gain. To create a decision conflict between approach of rewards and avoidance of fear-relevant angry faces, advantageous choices were associated with angry facial expressions, whereas disadvantageous choices were associated with happy facial expressions. Results indicated that higher social avoidance predicted less advantageous decisions in the beginning of the task, i.e., when contingencies were still uncertain. Interactions with specific skin conductance responses further clarified that this initial avoidance only occurred in combination with elevated responses before choosing an angry facial expressions. In addition, an interaction between high trait anxiety and elevated responses to early losses predicted faster learning of an advantageous strategy. These effects were independent of intelligence, general risky decision-making, self-reported state anxiety, and depression. Thus, socially avoidant individuals who respond emotionally to angry facial expressions are more likely to show avoidance of these faces under uncertainty. This novel laboratory paradigm may be an appropriate analog for central features of social anxiety.

  13. Optimizing Sampling Design to Deal with Mist-Net Avoidance in Amazonian Birds and Bats

    Science.gov (United States)

    Marques, João Tiago; Ramos Pereira, Maria J.; Marques, Tiago A.; Santos, Carlos David; Santana, Joana; Beja, Pedro; Palmeirim, Jorge M.

    2013-01-01

    Mist netting is a widely used technique to sample bird and bat assemblages. However, captures often decline with time because animals learn and avoid the locations of nets. This avoidance or net shyness can substantially decrease sampling efficiency. We quantified the day-to-day decline in captures of Amazonian birds and bats with mist nets set at the same location for four consecutive days. We also evaluated how net avoidance influences the efficiency of surveys under different logistic scenarios using re-sampling techniques. Net avoidance caused substantial declines in bird and bat captures, although more accentuated in the latter. Most of the decline occurred between the first and second days of netting: 28% in birds and 47% in bats. Captures of commoner species were more affected. The numbers of species detected also declined. Moving nets daily to minimize the avoidance effect increased captures by 30% in birds and 70% in bats. However, moving the location of nets may cause a reduction in netting time and captures. When moving the nets caused the loss of one netting day it was no longer advantageous to move the nets frequently. In bird surveys that could even decrease the number of individuals captured and species detected. Net avoidance can greatly affect sampling efficiency but adjustments in survey design can minimize this. Whenever nets can be moved without losing netting time and the objective is to capture many individuals, they should be moved daily. If the main objective is to survey species present then nets should still be moved for bats, but not for birds. However, if relocating nets causes a significant loss of netting time, moving them to reduce effects of shyness will not improve sampling efficiency in either group. Overall, our findings can improve the design of mist netting sampling strategies in other tropical areas. PMID:24058579

  14. Optimizing sampling design to deal with mist-net avoidance in Amazonian birds and bats.

    Directory of Open Access Journals (Sweden)

    João Tiago Marques

    Full Text Available Mist netting is a widely used technique to sample bird and bat assemblages. However, captures often decline with time because animals learn and avoid the locations of nets. This avoidance or net shyness can substantially decrease sampling efficiency. We quantified the day-to-day decline in captures of Amazonian birds and bats with mist nets set at the same location for four consecutive days. We also evaluated how net avoidance influences the efficiency of surveys under different logistic scenarios using re-sampling techniques. Net avoidance caused substantial declines in bird and bat captures, although more accentuated in the latter. Most of the decline occurred between the first and second days of netting: 28% in birds and 47% in bats. Captures of commoner species were more affected. The numbers of species detected also declined. Moving nets daily to minimize the avoidance effect increased captures by 30% in birds and 70% in bats. However, moving the location of nets may cause a reduction in netting time and captures. When moving the nets caused the loss of one netting day it was no longer advantageous to move the nets frequently. In bird surveys that could even decrease the number of individuals captured and species detected. Net avoidance can greatly affect sampling efficiency but adjustments in survey design can minimize this. Whenever nets can be moved without losing netting time and the objective is to capture many individuals, they should be moved daily. If the main objective is to survey species present then nets should still be moved for bats, but not for birds. However, if relocating nets causes a significant loss of netting time, moving them to reduce effects of shyness will not improve sampling efficiency in either group. Overall, our findings can improve the design of mist netting sampling strategies in other tropical areas.

  15. Avoidant decision making in social anxiety: the interaction of angry faces and emotional responses.

    Science.gov (United States)

    Pittig, Andre; Pawlikowski, Mirko; Craske, Michelle G; Alpers, Georg W

    2014-01-01

    Recent research indicates that angry facial expressions are preferentially processed and may facilitate automatic avoidance response, especially in socially anxious individuals. However, few studies have examined whether this bias also expresses itself in more complex cognitive processes and behavior such as decision making. We recently introduced a variation of the Iowa Gambling Task which allowed us to document the influence of task-irrelevant emotional cues on rational decision making. The present study used a modified gambling task to investigate the impact of angry facial expressions on decision making in 38 individuals with a wide range of social anxiety. Participants were to find out which choices were (dis-) advantageous to maximize overall gain. To create a decision conflict between approach of reward and avoidance of fear-relevant angry faces, advantageous choices were associated with angry facial expressions, whereas disadvantageous choices were associated with happy facial expressions. Results indicated that higher social avoidance predicted less advantageous decisions in the beginning of the task, i.e., when contingencies were still uncertain. Interactions with specific skin conductance responses further clarified that this initial avoidance only occurred in combination with elevated responses before choosing an angry facial expressions. In addition, an interaction between high trait anxiety and elevated responses to early losses predicted faster learning of an advantageous strategy. These effects were independent of intelligence, general risky decision-making, self-reported state anxiety, and depression. Thus, socially avoidant individuals who respond emotionally to angry facial expressions are more likely to show avoidance of these faces under uncertainty. This novel laboratory paradigm may be an appropriate analog for central features of social anxiety.

  16. Fuzzy logic path planning system for collision avoidance by an autonomous rover vehicle

    Science.gov (United States)

    Murphy, Michael G.

    1993-01-01

    The Space Exploration Initiative of the United States will make great demands upon NASA and its limited resources. One aspect of great importance will be providing for autonomous (unmanned) operation of vehicles and/or subsystems in space flight and surface exploration. An additional, complicating factor is that much of the need for autonomy of operation will take place under conditions of great uncertainty or ambiguity. Issues in developing an autonomous collision avoidance subsystem within a path planning system for application in a remote, hostile environment that does not lend itself well to remote manipulation by Earth-based telecommunications is addressed. A good focus is unmanned surface exploration of Mars. The uncertainties involved indicate that robust approaches such as fuzzy logic control are particularly appropriate. Four major issues addressed are (1) avoidance of a fuzzy moving obstacle; (2) backoff from a deadend in a static obstacle environment; (3) fusion of sensor data to detect obstacles; and (4) options for adaptive learning in a path planning system. Examples of the need for collision avoidance by an autonomous rover vehicle on the surface of Mars with a moving obstacle would be wind-blown debris, surface flow or anomalies due to subsurface disturbances, another vehicle, etc. The other issues of backoff, sensor fusion, and adaptive learning are important in the overall path planning system.

  17. Generalisation of fear and avoidance along a semantic continuum.

    Science.gov (United States)

    Boyle, Sean; Roche, Bryan; Dymond, Simon; Hermans, Dirk

    2016-01-01

    Directly conditioned fear and avoidance readily generalises to dissimilar but conceptually related stimuli. Here, for the first time, we examined the conceptual/semantic generalisation of both fear and avoidance using real words (synonyms). Participants were first exposed to a differential fear conditioning procedure in which one word (e.g., "broth"; CS+) was followed with brief electric shock [unconditioned stimulus (US)] and another was not (e.g., "assist"; CS-). Next, an instrumental conditioning phase taught avoidance in the presence the CS+ but not the CS-. During generalisation testing, synonyms of the CS+ (e.g., "soup"; GCS+) and CS- (e.g., "help"; GCS-) were presented in the absence of shock. Conditioned fear and avoidance, measured via skin conductance responses, behavioural avoidance and US expectancy ratings, generalised to the semantically related, but not to the semantically unrelated, synonyms. Findings have implications for how natural language categories and concepts mediate the expansion of fear and avoidance repertoires in clinical contexts.

  18. Individual differences in physiological flexibility predict spontaneous avoidance.

    Science.gov (United States)

    Aldao, Amelia; Dixon-Gordon, Katherine L; De Los Reyes, Andres

    2016-08-01

    People often regulate their emotions by resorting to avoidance, a putatively maladaptive strategy. Prior work suggests that increased psychopathology symptoms predict greater spontaneous utilisation of this strategy. Extending this work, we examined whether heightened resting cardiac vagal tone (which reflects a general ability to regulate emotions in line with contextual demands) predicts decreased spontaneous avoidance. In Study 1, greater resting vagal tone was associated with reduced spontaneous avoidance in response to disgust-eliciting pictures, beyond anxiety and depression symptoms and emotional reactivity. In Study 2, resting vagal tone interacted with anxiety and depression symptoms to predict spontaneous avoidance in response to disgust-eliciting film clips. The positive association between symptoms and spontaneous avoidance was more pronounced among participants with reduced resting vagal tone. Thus, increased resting vagal tone might protect against the use of avoidance. Our findings highlight the importance of assessing both subjective and biological processes when studying individual differences in emotion regulation.

  19. Excise tax avoidance: the case of state cigarette taxes.

    Science.gov (United States)

    DeCicca, Philip; Kenkel, Donald; Liu, Feng

    2013-12-01

    We conduct an applied welfare economics analysis of cigarette tax avoidance. We develop an extension of the standard formula for the optimal Pigouvian corrective tax to incorporate the possibility that consumers avoid the tax by making purchases in nearby lower tax jurisdictions. To provide a key parameter for our formula, we estimate a structural endogenous switching regression model of border-crossing and cigarette prices. In illustrative calculations, we find that for many states, after taking into account tax avoidance the optimal tax is at least 20% smaller than the standard Pigouvian tax that simply internalizes external costs. Our empirical estimate that tax avoidance strongly responds to the price differential is the main reason for this result. We also use our results to examine the benefits of replacing avoidable state excise taxes with a harder-to-avoid federal excise tax on cigarettes.

  20. Test anxiety and performance-avoidance goals explain gender differences in SAT-V, SAT-M, and overall SAT scores

    OpenAIRE

    Hannon, Brenda

    2012-01-01

    This study uses analysis of co-variance in order to determine which cognitive/learning (working memory, knowledge integration, epistemic belief of learning) or social/personality factors (test anxiety, performance-avoidance goals) might account for gender differences in SAT-V, SAT-M, and overall SAT scores. The results revealed that none of the cognitive/learning factors accounted for gender differences in SAT performance. However, the social/personality factors of test anxiety and performanc...

  1. AN ADAPTIVE REUSABLE LEARNING OBJECT FOR E-LEARNING USING COGNITIVE ARCHITECTURE

    OpenAIRE

    A.Kanimozhi; V.Cyrilraj

    2016-01-01

    Nowadays, a huge amount of ambiguous e-learning materials are available in World Wide Web irrespective of various objectives. These digital educational resources can be reused and shared from centralized online repository and it will avoid the redundant learning material. The main goal is to design consistent adaptable e-learning course material for web-based education system with emphasis on the quality of learning. This can be done by organizing learning object in a prescribed m...

  2. Avoidance and tolerance to avian herbivores in aquatic plants

    OpenAIRE

    Hidding, A.

    2009-01-01

    Tolerance and avoidance are the two contrasting strategies that plants may adopt to cope with herbivores. Tolerance traits define the degree to which communities remain unaffected by herbivory. Trade-offs between herbivore avoidance and competitive strength and between avoidance and colonization ability may shape population traits and communities under herbivory. In this thesis I present comparative and experimental studies on populations and communities of aquatic plants and how they deal wi...

  3. The mnemonic mover: nostalgia regulates avoidance and approach motivation

    OpenAIRE

    Stephan, Elena; Wildschut, Tim; Sedikides, Constantine; Zhou, X.; He, W.; Routledge, Clay; Cheung, Wing-Yee; Vingerhoets, A.

    2014-01-01

    In light of its role in maintaining psychological equanimity, we proposed that nostalgia—a self-relevant, social, and predominantly positive emotion—regulates avoidance and approach motivation. We advanced a model in which (a) avoidance motivation triggers nostalgia and (b) nostalgia, in turn, increases approach motivation. As a result, nostalgia counteracts the negative impact of avoidance motivation on approach motivation. Five methodologically diverse studies supported this regulatory mode...

  4. Multiobjective Optimization Based Vessel Collision Avoidance Strategy Optimization

    OpenAIRE

    Qingyang Xu; Chuang Zhang; Ning Wang

    2014-01-01

    The vessel collision accidents cause a great loss of lives and property. In order to reduce the human fault and greatly improve the safety of marine traffic, collision avoidance strategy optimization is proposed to achieve this. In the paper, a multiobjective optimization algorithm NSGA-II is adopted to search for the optimal collision avoidance strategy considering the safety as well as economy elements of collision avoidance. Ship domain and Arena are used to evaluate the collision risk in ...

  5. Who Avoids Cancer Information? Examining a Psychological Process Leading to Cancer Information Avoidance.

    Science.gov (United States)

    Chae, Jiyoung

    2016-07-01

    Although cancer information avoidance (CIA) is detrimental to public health, predictors of CIA have not been fully investigated. Based on uncertainty management theory, this study viewed CIA as a response to uncertainty related to the distress associated with cancer information and illustrated the psychological process leading to CIA. Given the current information context, it was hypothesized that cancer information overload (CIO), accompanied by confusion and stress about cancer information, causes CIA. As trait anxiety is a strong predictor of CIO, it was also hypothesized that trait anxiety has an indirect effect on CIA through CIO. Study 1 tested this relationship in a U.S. sample (N = 384); the results showed that CIO was positively associated with CIA and that trait anxiety indirectly influenced CIA through CIO. Whereas Study 1 tested the relationship with cross-sectional data in the general cancer context, Study 2 replicated Study 1 with 3-wave longitudinal data in the context of a specific cancer (i.e., stomach cancer) in South Korea (N = 1,130 at Wave 1, 813 at Wave 2, and 582 at Wave 3). Trait anxiety at Wave 1 predicted CIO at Wave 2, which in turn increased CIA at Wave 3, suggesting that some people are inherently inclined to avoid cancer information due to their trait anxiety, which results in confusion about cancer information. PMID:27337343

  6. Real-Time Hazard Detection and Avoidance Demonstration for a Planetary Lander

    Science.gov (United States)

    Epp, Chirold D.; Robertson, Edward A.; Carson, John M., III

    2014-01-01

    The Autonomous Landing Hazard Avoidance Technology (ALHAT) Project is chartered to develop and mature to a Technology Readiness Level (TRL) of six an autonomous system combining guidance, navigation and control with terrain sensing and recognition functions for crewed, cargo, and robotic planetary landing vehicles. In addition to precision landing close to a pre-mission defined landing location, the ALHAT System must be capable of autonomously identifying and avoiding surface hazards in real-time to enable a safe landing under any lighting conditions. This paper provides an overview of the recent results of the ALHAT closed loop hazard detection and avoidance flight demonstrations on the Morpheus Vertical Testbed (VTB) at the Kennedy Space Center, including results and lessons learned. This effort is also described in the context of a technology path in support of future crewed and robotic planetary exploration missions based upon the core sensing functions of the ALHAT system: Terrain Relative Navigation (TRN), Hazard Detection and Avoidance (HDA), and Hazard Relative Navigation (HRN).

  7. Reading Methodologies for African Languages: Avoiding Linguistic and Pedagogical Imperialism

    Science.gov (United States)

    Trudell, Barbara; Schroeder, Leila

    2007-01-01

    Learning to read and write is a psycholinguistic and social process. That is why mother-tongue speakers of minority African languages find learning to read in the language they speak is a qualitatively better learning experience than learning to read in a language they are unfamiliar with. However, reading methodologies used for teaching reading…

  8. Approach, avoidance, and affect: a meta-analysis of approach-avoidance tendencies in manual reaction time tasks

    OpenAIRE

    Phaf, R. Hans; Mohr, Sören E.; Rotteveel, Mark; Jelte M Wicherts

    2014-01-01

    Approach action tendencies toward positive stimuli and avoidance tendencies from negative stimuli are widely seen to foster survival. Many studies have shown that approach and avoidance arm movements are facilitated by positive and negative affect, respectively. There is considerable debate whether positively and negatively valenced stimuli prime approach and avoidance movements directly (i.e., immediate, unintentional, implicit, automatic, and stimulus-based), or indirectly (i.e., after cons...

  9. Approach, avoidance, and affect: A meta-analysis of approach-avoidance tendencies in manual reaction time tasks

    OpenAIRE

    Hans ePhaf; Sören Erik Mohr; Mark eRotteveel; Jelte M Wicherts

    2014-01-01

    Approach action tendencies towards positive stimuli and avoidance tendencies from negative stimuli are widely seen to foster survival. Many studies have shown that approach and avoidance arm movements are facilitated by positive and negative affect, respectively. There is considerable debate whether positively and negatively valenced stimuli prime approach and avoidance movements directly (i.e., immediate, unintentional, implicit, automatic, and stimulus-based), or indirectly (i.e., after con...

  10. What you want to avoid is what you see: Social avoidance motivation affects the interpretation of emotional faces

    OpenAIRE

    Nikitin, Jana; Freund, Alexandra M.

    2015-01-01

    This study investigated the effects of habitual social approach and avoidance motivation on the classification of facial expressions of different visual clarity. Participants (N = 78) categorized partially masked emotional faces expressing either anger or happiness as positive or negative. Participants generally tended to interpret the facial expressions in a positive way. This positivity effect was reduced when persons were highly avoidance motivated. Social avoidance motivation predicted fe...

  11. Rapid avoidance acquisition in Wistar-Kyoto rats.

    Science.gov (United States)

    Servatius, R J; Jiao, X; Beck, K D; Pang, K C H; Minor, T R

    2008-10-10

    The relationship between trait stress-sensitivity, avoidance acquisition and perseveration of avoidance was examined using male Wistar-Kyoto (WKY) and Sprague-Dawley (SD) rats. Behavior in an open field was measured prior to escape/avoidance (E/A) acquisition and extinction. E/A was assessed in a discrete trial lever-press protocol. The signal-shock interval was 60s with subsequent shocks delivered every 3s until a lever-press occurred. A 3-min flashing light safety signal was delivered contingent upon a lever-press (or failure to respond in 5 min). WKY rats displayed phenotypic low open field activity, but were clearly superior to SD rats in E/A performance. As avoidance responses were acquired and reached asymptotic performance, SD rats exhibited "warm up", that is, SD rats rarely made avoidance responses on the initial trial of a session, even though later trials were consistently accompanied with avoidance responses. In contrast, WKY rats did not show the "warm up" pattern and avoided on nearly all trials of a session including the initial trial. In addition to the superior acquisition of E/A, WKY rats demonstrated several other avoidance features that were different from SD rats. Although the rates of nonreinforced intertrial responses (ITRs) were relatively low and selective to the early safety period, WKY displayed more ITRs than SD rats. With removal of the shocks extinction was delayed in WKY rats, likely reflecting their nearly perfect avoidance performance. Even after extensive extinction, first trial avoidance and ITRs were evident in WKY rats. Thus, WKY rats have a unique combination of trait behavioral inhibition (low open field activity and stress sensitivity) and superior avoidance acquisition and response perseveration making this strain a good model to understand anxiety disorders.

  12. Scopolamine and acquisition of go-no go avoidance: a further analysis of the perseverative antimuscarinic deficit.

    Science.gov (United States)

    Giardini, V; Amorico, L; De Acetis, L; Bignami, G

    1983-01-01

    Rats treated with scopolamine (0.5 mg/kg SC daily) during the acquisition of a discrimination task with symmetrical negative reinforcement (light-go, noise/light-no go) showed a learning impairment, with both active and passive avoidance deficits. In the initial stage of such training, however, fewer passive avoidance errors and more active avoidance errors were made by treated animals if active avoidance pretraining had occurred in the no-drug state. A similar experiment using the same stimulus arrangement with asymmetrical reinforcement (no punishment of intertrial, and no go signal, responses) showed a scopolamine effect consisting mainly of increased responding to extinction signals and during intertrial intervals, with little or no active avoidance deficit. Furthermore, interactions due to changes in treatment conditions in successive stages of training were minimized in the latter task, suggesting that the effects of the shift-no shift factor on distribution of errors in the early stages of active-passive avoidance learning were unlikely to have been due to a genuine drug dissociation. Overall, these results and others obtained previously in the same and related tasks tend to rule out some unidimensional explanations of antimuscarinic effects, e.g., response disinhibition (an exclusively motor deficit) or impairment of stimulus sensitivity (an exclusively sensory deficit). The data rather confirm the notion of a sensorimotor drug bias leading to a shift in response prepotencies depending jointly on stimuli, responses, and response consequences. Prior learning history and behavioural compensation for adverse treatment consequences at the reinforcement level may interact with the sensorimotor bias so as to produce "set perseveration" (perseveration of response tendencies). PMID:6410441

  13. Learn about gluten-free diets

    Science.gov (United States)

    ... medlineplus.gov/ency/patientinstructions/000813.htm Learn about gluten-free diets To use the sharing features on ... research to support this idea. Reasons to Avoid Gluten People follow a gluten-free diet for a ...

  14. The Prediction of Antisocial Behavior from Avoidant Attachment Classifications.

    Science.gov (United States)

    Fagot, Beverly I.; Kavanagh, Kate

    1990-01-01

    Children of 18 months classified as secure or insecure/avoidant by means of the Ainsworth Strange Situation were observed at home and in a playgroup. Teachers and observers rated girls classified as insecure/avoidant as being more difficult to deal with and having more difficulty with peers than girls rated as securely attached. (PCB)

  15. Research on Double Collision Avoidance Mechanism of Ships at Sea

    Directory of Open Access Journals (Sweden)

    XiuYing Bi

    2015-03-01

    Full Text Available When power driven vessels encounter at sea, they need to avoid collision. The definition of right vessel may mislead ships officers think his or her direct navigating has absolute power with this special ship. This paper will define DCPA symbols; give the cause and the method of double collision avoidance mechanism of ships at sea.

  16. Tax avoidance with cross-border hybrid instruments

    DEFF Research Database (Denmark)

    Johannesen, Niels

    2014-01-01

    in the other country with a cross-border hybrid instrument. We then investigate why countries tend to allow the use of hybrid instruments for tax avoidance and show that even if effective anti-avoidance rules are available, there exists a global policy equilibrium in which no country uses such rules...

  17. Verbal Avoidance and Dissatisfaction in Intimate Conflict Situations

    Science.gov (United States)

    Afifi, Tamara D.; McManus, Tara; Steuber, Keli; Coho, Amanda

    2009-01-01

    The purpose of this study was to more closely examine the association between avoidance and satisfaction during a potentially conflict-inducing conversation with one's dating partner. The results suggest that the way people respond to their own and their partner's conflict avoidance depends upon whether they are male or female. The perception of…

  18. The inhibitory avoidance discrimination task to investigate accuracy of memory

    NARCIS (Netherlands)

    Atucha Trevino, E.; Roozendaal, B.

    2015-01-01

    The present study was aimed at developing a new inhibitory avoidance task, based on training and/or testing rats in multiple contexts, to investigate accuracy of memory. In the first experiment, male Sprague-Dawley rats were given footshock in an inhibitory avoidance apparatus and, 48 h later, reten

  19. Principles of obstacle avoidance with a transfemoral prosthetic limb

    NARCIS (Netherlands)

    van Keeken, Helco G.; Vrieling, Aline H.; Hof, At L.; Postema, Klaas; Otten, Bert

    2012-01-01

    In this study, conditions that enable a prosthetic knee flexion strategy in transfemoral amputee subjects during obstacle avoidance were investigated. This study explored the hip torque principle and the static ground principle as object avoidance strategies. A prosthetic limb simulator device was u

  20. Panic disorder : A baseline period : predictability of agoraphobic avoidance behavior

    NARCIS (Netherlands)

    De Jong, G.Majella; Bouman, Theo K.

    1995-01-01

    This study addresses the relationship between panic symptomatology and situational avoidance behaviour. Eighty panic disordered patients were involved with various degrees of agoraphobia, ranging from nonavoidant to extremely avoidant. Subjects recorded panic attacks by means of a diary for a period

  1. 31 CFR 800.104 - Transactions or devices for avoidance.

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Transactions or devices for avoidance. 800.104 Section 800.104 Money and Finance: Treasury Regulations Relating to Money and Finance..., ACQUISITIONS, AND TAKEOVERS BY FOREIGN PERSONS General § 800.104 Transactions or devices for avoidance....

  2. 47 CFR 15.711 - Interference avoidance mechanisms.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Interference avoidance mechanisms. 15.711 Section 15.711 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES Television Band Devices § 15.711 Interference avoidance mechanisms. (a) Except as provided in §...

  3. 5 CFR 950.109 - Avoidance of conflict of interest.

    Science.gov (United States)

    2010-01-01

    ... 5 Administrative Personnel 2 2010-01-01 2010-01-01 false Avoidance of conflict of interest. 950.109 Section 950.109 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT (CONTINUED) CIVIL SERVICE... PRIVATE VOLUNTARY ORGANIZATIONS General Provisions § 950.109 Avoidance of conflict of interest....

  4. 34 CFR 75.611 - Avoidance of flood hazards.

    Science.gov (United States)

    2010-07-01

    ... 34 Education 1 2010-07-01 2010-07-01 false Avoidance of flood hazards. 75.611 Section 75.611 Education Office of the Secretary, Department of Education DIRECT GRANT PROGRAMS What Conditions Must Be Met by a Grantee? Construction § 75.611 Avoidance of flood hazards. In planning the construction,...

  5. 14 CFR 125.224 - Collision avoidance system.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Collision avoidance system. 125.224 Section... Requirements § 125.224 Collision avoidance system. Effective January 1, 2005, any airplane you operate under this part 125 must be equipped and operated according to the following table: Collision...

  6. 38 CFR 4.14 - Avoidance of pyramiding.

    Science.gov (United States)

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false Avoidance of pyramiding. 4.14 Section 4.14 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS SCHEDULE FOR RATING DISABILITIES General Policy in Rating § 4.14 Avoidance of pyramiding. The evaluation of...

  7. 29 CFR 1912.4 - Avoidance of duplication.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Avoidance of duplication. 1912.4 Section 1912.4 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) ADVISORY COMMITTEES ON STANDARDS Organizational Matters § 1912.4 Avoidance of duplication....

  8. 16 CFR 801.90 - Transactions or devices for avoidance.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Transactions or devices for avoidance. 801.90 Section 801.90 Commercial Practices FEDERAL TRADE COMMISSION RULES, REGULATIONS, STATEMENTS AND... Transactions or devices for avoidance. Any transaction(s) or other device(s) entered into or employed for...

  9. How to Avoid the ER If You Have Asthma

    Science.gov (United States)

    ... How to Avoid the ER if You Have Asthma KidsHealth > For Teens > How to Avoid the ER if You Have Asthma Print A A A Text Size What's in ... is the last resort for someone who has asthma. If a flare-up is really out of ...

  10. How do walkers avoid a mobile robot crossing their way?

    CERN Document Server

    Vassallo, Christian; Souères, Philippe; Crétual, Armel; Stasse, Olivier; Pettré, Julien

    2016-01-01

    Robots and Humans have to share the same environment more and more often. In the aim of steering robots in a safe and convenient manner among humans it is required to understand how humans interact with them. This work focuses on collision avoidance between a human and a robot during locomotion. Having in mind previous results on human obstacle avoidance, as well as the description of the main principles which guide collision avoidance strategies, we observe how humans adapt a goal-directed locomotion task when they have to interfere with a mobile robot. Our results show differences in the strategy set by humans to avoid a robot in comparison with avoiding another human. Humans prefer to give the way to the robot even when they are likely to pass first at the beginning of the interaction.

  11. Multiobjective Optimization Based Vessel Collision Avoidance Strategy Optimization

    Directory of Open Access Journals (Sweden)

    Qingyang Xu

    2014-01-01

    Full Text Available The vessel collision accidents cause a great loss of lives and property. In order to reduce the human fault and greatly improve the safety of marine traffic, collision avoidance strategy optimization is proposed to achieve this. In the paper, a multiobjective optimization algorithm NSGA-II is adopted to search for the optimal collision avoidance strategy considering the safety as well as economy elements of collision avoidance. Ship domain and Arena are used to evaluate the collision risk in the simulation. Based on the optimization, an optimal rudder angle is recommended to navigator for collision avoidance. In the simulation example, a crossing encounter situation is simulated, and the NSGA-II searches for the optimal collision avoidance operation under the Convention on the International Regulations for Preventing Collisions at Sea (COLREGS. The simulation studies exhibit the validity of the method.

  12. A Robust Obstacle Avoidance for Service Robot Using Bayesian Approach

    Directory of Open Access Journals (Sweden)

    Widodo Budiharto

    2011-03-01

    Full Text Available The objective of this paper is to propose a robust obstacle avoidance method for service robot in indoor environment. The method for obstacles avoidance uses information about static obstacles on the landmark using edge detection. Speed and direction of people that walks as moving obstacle obtained by single camera using tracking and recognition system and distance measurement using 3 ultrasonic sensors. A new geometrical model and maneuvering method for moving obstacle avoidance introduced and combined with Bayesian approach for state estimation. The obstacle avoidance problem is formulated using decision theory, prior and posterior distribution and loss function to determine an optimal response based on inaccurate sensor data. Algorithms for moving obstacles avoidance method proposed and experiment results implemented to service robot also presented. Various experiments show that our proposed method very fast, robust and successfully implemented to service robot called Srikandi II that equipped with 4 DOF arm robot developed in our laboratory.

  13. Learning How To Learn.

    Science.gov (United States)

    Barnett, Demian

    2000-01-01

    In one California high school, learning to learn is a measurable outcome assessed by all students' participation in graduation by exhibition. Students must meet state requirements and demonstrate learning prowess by publicly exhibiting their skills in math, science, language arts, social science, service learning, and postgraduation planning. (MLH)

  14. A Summary of the NASA ISS Space Debris Collision Avoidance Program

    Science.gov (United States)

    Frisbee, Joseph

    2002-01-01

    Creating and implementing a process for the mitigation of the impact hazards due to cornets and asteroids will prove to be a complex and involved process. The closest similar program is the collision avoidance process currently used for protection of the International Space Station (ISS). This process, in operation for over three years, has many similarities to the NEG risk problem. By reviewing the ISS program, a broader perspective on the complications of and requirements for a NEO risk mitigation program might be obtained. Specifically, any lessons learned and continuing issues of concern might prove useful in the development of a NEO risk assessment and mitigation program.

  15. Historical comment on DSM-III schizoid and avoidant personality disorders.

    Science.gov (United States)

    Livesley, W J; West, M; Tanney, A

    1985-11-01

    The authors examine the DSM-III distinction between schizoid and avoidant personality disorders. This distinction is based on Millon's biosocial learning theory and his interpretation of Kretschmer's personality types. The authors argue that this separation of a continuous distribution is historically misconceived and serves to obscure the significant features of schizoid personality. They examine Kretschmer's conceptualization of schizoid personality for the implications it carries for the development of a classification of personality disorder, suggesting that Kretschmer's approach implies a "polythetic" model of personality disorder that conceptualizes disorders as categories of dimensions.

  16. Approach, avoidance, and affect: a meta-analysis of approach-avoidance tendencies in manual reaction time tasks

    NARCIS (Netherlands)

    R.H. Phaf; S.E. Mohr; M. Rotteveel; J.M. Wicherts

    2014-01-01

    Approach action tendencies toward positive stimuli and avoidance tendencies from negative stimuli are widely seen to foster survival. Many studies have shown that approach and avoidance arm movements are facilitated by positive and negative affect, respectively. There is considerable debate whether

  17. Reduction in Memory Specificity Following an Approach/Avoidance Scrambled Sentences Task Relates to Cognitive Avoidant Coping

    Science.gov (United States)

    Debeer, Elise; Raes, Filip; Williams, J. Mark G.; Hermans, Dirk

    2013-01-01

    "Overgeneral autobiographical memory" (OGM) refers to the tendency to retrieve less specific personal memories. According to the functional avoidance hypothesis, OGM might act as a cognitive strategy to avoid emotionally distressing details of negative memories. In the present study, we investigated the effect of an experimentally induced avoidant…

  18. On the role of subsecond dopamine release in conditioned avoidance

    Directory of Open Access Journals (Sweden)

    Erik B Oleson

    2013-06-01

    Full Text Available Using shock avoidance procedures to study conditioned behavioral responses has a rich history within the field of experimental psychology. Such experiments led to the formulation of the general concept of negative reinforcement and specific theories attempting to explain escape and avoidance behavior, or why animals choose to either terminate or prevent the presentation of an aversive event. For example, the two-factor theory of avoidance holds that cues preceding an aversive event begin to evoke conditioned fear responses, and these conditioned fear responses reinforce the instrumental avoidance response. Current neuroscientific advances are providing new perspectives into this historical literature. Due to its well-established role in reinforcement processes and behavioral control, the mesolimbic dopamine system presented itself as a logical starting point in the search for neural correlates of avoidance and escape behavior. We recently demonstrated that phasic dopamine release events are inhibited by stimuli associated with aversive events but increased by stimuli preceding the successful avoidance of the aversive event. The latter observation is inconsistent with the second component of the two-factor theory of avoidance and; therefore, led us propose a new theoretical explanation of conditioned avoidance: 1 fear is initially conditioned to the warning signal and dopamine computes this fear association as a decrease in release, 2 the warning signal, now capable of producing a negative emotional state, suppresses dopamine release and behavior, 3 over repeated trials the warning signal becomes associated with safety rather than fear; dopaminergic neurons already compute safety as an increase in release and begin to encode the warning signal as the earliest predictor of safety 4 the warning signal now promotes conditioned avoidance via dopaminergic modulation of the brain’s incentive-motivational circuitry.

  19. 规避编程过程中的不确定性--一种新的适用于通识课程的教学方法%Uncertainty Avoidance-A New Teaching/Learning Method for an Introductory Programming Course

    Institute of Scientific and Technical Information of China (English)

    Zhen Jiang

    2016-01-01

    针对非计算机专业学生数学和计算机编程薄弱的问题,介绍一个让学生快速掌握决策结构(If-else/If 语句)的教学方法。文章演示如何在CSC115这一门通识课中应用该方法,帮助这些基础不够的学生跨越学习过程中的种种不同的疑惑,从而迅速提升学生识习判断语句后的编程技巧。和其他方法(诸如传统的积累方法)不同,该方法更注重循序渐进地对关键技术点进行讲解,以期这些学生能在现有的技术技能基础上理解和执行。这样,学生的学习更加有效和快速。%In this paper, we introduce a new procedure for under-represented students to quickly learn the use of the decision structure in computer programming. The challenge here is to help students, who lack sufficient background of mathematics and computer programming, to use this structure correctly without too much doubt and uncertainty. The traditional CS0 program elapses several semesters and requires many foundation courses to be taken before the students have knowledge of the program correctness. Our one-semester course CSC115 allows students to build up programming skills gradually case by case and program by program. Such a guideline is proven to be effective for those inexperienced students to write correct If-else/If statements without the need for learning formal methods in classroom.

  20. Learning How to Learn

    DEFF Research Database (Denmark)

    Lauridsen, Karen M.; Lauridsen, Ole

    presented in a way that suits their individual LS preferences. In this presentation you will see how we as teachers can assist students in applying LS strategies that cater to their individual learning strengths. This will be based on general recommendations for HE teaching and learning supported......Ole Lauridsen, Aarhus School of Business and Social Sciences, Aarhus University, Denmark Karen M. Lauridsen, Aarhus School of Business and Social Sciences, Aarhus University, Denmark Learning Styles in Higher Education – Learning How to Learn Applying learning styles (LS) in higher education...... teaching leads to positive results and enhanced student learning. However, learning styles should not only be considered a didactic matter for the teacher, but also a tool for the individual students to improve their learning capabilities – not least in contexts where information is not necessarily...

  1. Rethinking Oedipus: an evolutionary perspective of incest avoidance.

    Science.gov (United States)

    Erickson, M T

    1993-03-01

    The author presents a biological hypothesis of incest avoidance. Pertinent literature from evolutionary biology, ethology, anthropology, and clinical research is reviewed. Secure early bonding to immediate kin predicts later adaptive kin-directed behaviors, including preferential altruism (kin selection) and incest avoidance. Impaired bonding predicts aberrant kin-directed behavior, including diminished altruism, neglect, and an increased incidence of incest. Failed bonding predicts the highest frequency of incest. Secure bonding to kin may function to establish adaptive kin-directed behaviors, including incest avoidance. Bonding is conceived of as the developmental foundation of a form of social attraction, here called "familial attraction," which is evolutionarily distinct from sexual attraction.

  2. Obstacle-avoidance automatic guidance - A concept-development study

    Science.gov (United States)

    Cheng, Victor H. L.

    1988-01-01

    This paper studies the notion of obstacle-avoidance guidance, and investigates the issues in automating this function by considering helicopter nap-of-the-earth (NOE) flight as an example. In particular, it considers a hierarchy of guidance components, including mission planning and obstacle avoidance. Based on this hierarchical breakdown, the functional requirements of obstacle-avoidance guidance are identified. An effort in developing automatic guidance algorithms to meet these requirements is presented, along with the necesssary simulation tools for evaluation of these algorithms.

  3. Braking news: link between crash severity and crash avoidance maneuvers

    DEFF Research Database (Denmark)

    Kaplan, Sigal; Prato, Carlo Giacomo

    2012-01-01

    This study focused on the link between crash severity and crash avoidance maneuvers. Various emergency lateral and speed control maneuvers were considered in response to different critical events that made the crash imminent. Partial proportional odds models that allowed for changes in effects...... crash avoidance maneuvers and crash severity, with differences emerging for different critical events. Moreover, results showed two trends:(a) most drivers failed to act when facing critical events and (b) drivers rarely performed crash avoidance maneuvers that were correlated with a higher probability...

  4. Obstacle Avoidance for Unmanned Undersea Vehicle in Unknown Unstructured Environment

    Directory of Open Access Journals (Sweden)

    Zheping Yan

    2013-01-01

    Full Text Available To avoid obstacle in the unknown environment for unmanned undersea vehicle (UUV, an obstacle avoiding system based on improved vector field histogram (VFH is designed. Forward looking sonar is used to detect the environment, and the divisional sonar modal is applied to deal with the measure uncertainty. To adapt to the VFH, rolling occupancy grids are used for the map building, and high accuracy details of local environment are obtained. The threshold is adaptively adjusted by the statistic of obstacles to solve the problem that VFH is sensitive to threshold. To improve the environment adaptability, the hybrid-behaviors strategy is proposed, which selects the optimal avoidance command according to the motion status and environment character. The simulation shows that UUV could avoid the obstacles fast and escape from the U shape obstacles.

  5. Neurobehavioral Study on Social Transmission of Avoidance Behavior

    OpenAIRE

    Masuda, Akira

    2010-01-01

    CHAPTER 1INTRODUCTION||CHAPTER 2BEHAVIORAL STUDIES: BEHAVIORAL CHARACTERISTICS OF THE SOCIAL TRANSMISSION||CHAPTER 3LESION STUDIES: IDENTIFICATION OF IMPORTANT BRAIN AREAS FOR SOCIAL TRANSMISSION OF AVOIDANCE||CHAPTER 4CONCLUSION||Publication List

  6. Optical Obstacle Avoidance System for Lunar and Mars Landing Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The systems developed at fibertek for Obstacle-Avoidance has so far all been operated at 1560nm. Such an operation is required due to the required eye-safety...

  7. The Use of Arbitration to Avoid Litigation Under ERISA

    Science.gov (United States)

    Donaldson, Richard P.

    1975-01-01

    In this symposium report it is suggested that arbitration can be used to avoid litigation of ERISA pension and welfare benefit claims if the negotiated plan or related collective bargaining agreement provides for arbitration or benefit disputes. (Author/LBH)

  8. AVOIDING RISK IN WORKING CAPITAL CREDIT DISTRIBUTION IN INDONESIA

    Directory of Open Access Journals (Sweden)

    Aloysius Deno Hervino

    2011-09-01

    Full Text Available This research analyzes risk avoidance behaviour of banking institutions in distributing working capital loan in Indonesia. Using Autoregressive Distributed Lag Error Correction Model, this paper uncovers three findings. First, in the short run, risk avoidance in working capital loan distribution depends on inter-call banking money market and Sertifikat Bank Indonesia. Second, following banking regulation after 1997 crisis, banks have become more careful in distributing credits, with SBI as a substitution instrument and inter-call banking money market as a complement instrument to spread the risk. Third, all explanatory variables take an average of 6 days or 1 week to influence bank’s risk avoidance behaviour.Keywords:     Risk avoidance, working capital distribution, banking institutions JEL classification numbers: C32, C52, D81, E51

  9. You Have Diabetes. How Can You Avoid Serious Eye Diseases?

    Science.gov (United States)

    ... Day You have diabetes. How can you avoid serious eye diseases? Did you know that diabetic retinopathy, an eye ... Or that the number of people with this serious eye disease that damages the blood vessels inside the retina, ...

  10. [The history and current state of communication avoidance research].

    Science.gov (United States)

    Sakamoto, M; Pribyl, C B; Keaten, J

    1998-02-01

    The ability to communicate effectively has a profound impact on academic ability and social status in the United States. As such, communication avoidance may impart critical consequences on individuals who suffer from it. Within the communication discipline, communication avoidance is an extensive body of research with a relatively long history. Central to communication avoidance research is the concept of communication apprehension (CA). However, in comparison with research conducted in the United States, CA research in Japan remains in its genesis. This review thus focuses on communication apprehension and related constructs. Starting with an explanation of the magnitude of the problem of communication avoidance, a definition of CA is presented, and an overview of the related constructs of reticence, shyness, and other communication-related fears is introduced. Basic CA treatment programs and personality correlates of CA are also covered. The review closes by offering suggestions for future CA research in Japan. PMID:9626739

  11. Parents: Avoid Kids Foot Problems with the Right Shoes

    Science.gov (United States)

    ... Print | Share Avoid Kids Foot Problems with the Right Shoes Before you head to the store to ... College of Foot and Ankle Surgeons (ACFAS), All Rights Reserved. Privacy Statement | Disclaimer | Terms and Conditions | Site ...

  12. Does the Organized Sexual Murderer Better Delay and Avoid Detection?

    Science.gov (United States)

    Beauregard, Eric; Martineau, Melissa

    2016-01-01

    According to the organized-disorganized model, organized sexual murderers adopt specific behaviors during the commission of their crimes that contribute to avoiding police detection. The current study examines the effect of sexual murderers' organized behaviors on their ability to both delay and/or avoid police detection. Using a combination of negative binomial and logistic regression analyses on a sample of 350 sexual murder cases, findings showed that although both measures of delaying and avoiding detection are positively correlated, different behavioral patterns were observed. For instance, offenders who moved the victim's body were more likely to avoid detection but the victim's body was likely to be recovered faster. Moreover, victim characteristics have an impact on both measures; however, this effect disappears for the measure of delaying detection once the organized behaviors are introduced. Implications of the findings are discussed.

  13. Optimal deadlock avoidance Petri net supervisors for automated manufacturing systems

    Institute of Scientific and Technical Information of China (English)

    Keyi XING; Feng TIAN; Xiaojun YANG

    2007-01-01

    Deadlock avoidance problems are investigated for automated manufacturing systems with flexible routings.Based on the Petri net models of the systems, this paper proposes, for the first time, the concept of perfect maximal resourcetransition circuits and their saturated states. The concept facilitates the development of system liveness characterization and deadlock avoidance Petri net supervisors. Deadlock is characterized as some perfect maximal resource-transition circuits reaching their saturated states. For a large class of manufacturing systems, which do not contain center resources, the optimal deadlock avoidance Petri net supervisors are presented. For a general manufacturing system, a method is proposed for reducing the system Petri net model so that the reduced model does not contain center resources and, hence, has optimal deadlock avoidance Petri net supervisor. The controlled reduced Petri net model can then be used as the liveness supervisor of the system.

  14. Minding Your Metabolism: Can You Avoid Middle-Age Spread?

    Science.gov (United States)

    ... please review our exit disclaimer . Subscribe Minding Your Metabolism Can You Avoid Middle-Age Spread? As you age, you may notice you have less muscle and energy and more fat. Carrying those extra ...

  15. Plans and Measures for Avoiding Casting-Air-Pollution

    Institute of Scientific and Technical Information of China (English)

    ZHOU Jian

    2003-01-01

    This article presents plans of preventing casting-air-pollution in practice, and some avoiding methods in detail. In modern times, environment protection is looked high upon day by day; green-casting thus becomes more and more important.

  16. US Forest Service Aerial Fire Retardant Avoidance Areas: Terrestrial

    Data.gov (United States)

    US Forest Service, Department of Agriculture — A map service depicting aerial fire retardant avoidance areas delivered as part of the 2011 Nationwide Aerial Application of Fire Retardant on National Forest...

  17. Tautological Explanations and Definitions--An Avoidable Phenomenon.

    Science.gov (United States)

    Jungwirth, E.

    1986-01-01

    Reviews findings from three diagnostic studies which focused on the problem of tautological explanations. Includes a report on a teaching intervention strategy which resulted in the improvement of pupil performance. Suggests that avoidance of tautology can be taught. (ML)

  18. Contextual modulation of value signals in reward and punishment learning.

    OpenAIRE

    Palminteri, S., Khamassi, M., Joffily, M., Coricelli, G.; Khamassi, M.; Joffily, M.; Coricelli, G.

    2015-01-01

    Compared with reward seeking, punishment avoidance learning is less clearly understood at both the computational and neurobiological levels. Here we demonstrate, using computational modelling and fMRI in humans, that learning option values in a relative--context-dependent--scale offers a simple computational solution for avoidance learning. The context (or state) value sets the reference point to which an outcome should be compared before updating the option value. Consequently, in contexts w...

  19. Avoid, Control, Succumb, or Balance: Engineering Students' Approaches to a Wicked Sustainability Problem

    Science.gov (United States)

    Lönngren, Johanna; Ingerman, Åke; Svanström, Magdalena

    2016-07-01

    Wicked sustainability problems (WSPs) are an important and particularly challenging type of problem. Science and engineering education can play an important role in preparing students to deal with such problems, but current educational practice may not adequately prepare students to do so. We address this gap by providing insights related to students' abilities to address WSPs. Specifically, we aim to (I) describe key constituents of engineering students' approaches to a WSP, (II) evaluate these approaches in relation to the normative context of education for sustainable development (ESD), and (III) identify relevant aspects of learning related to WSPs. Aim I is addressed through a phenomenographic study, while aims II and III are addressed by relating the results to research literature about human problem solving, sustainable development, and ESD. We describe four qualitatively different ways of approaching a specific WSP, as the outcome of the phenomenographic study: A. Simplify and avoid, B. Divide and control, C. Isolate and succumb, and D. Integrate and balance. We identify approach D as the most appropriate approach in the context of ESD, while A and C are not. On this basis, we identify three learning objectives related to students' abilities to address WSPs: learn to use a fully integrative approach, distinguish WSPs from tame and well-structured problems, and understand and consider the normative context of SD. Finally, we provide recommendations for how these learning objectives can be used to guide the design of science and engineering educational activities.

  20. Critical period of memory enhancement during taste avoidance conditioning in Lymnaea stagnalis.

    Directory of Open Access Journals (Sweden)

    Tomoyo Takahashi

    Full Text Available The present study investigated the optimal training procedure leading to long-lasting taste avoidance behavior in Lymnaea. A training procedure comprising 5 repeated pairings of a conditional stimulus (CS, sucrose, with an unconditional stimulus (US, a tactile stimulation to the animal's head, over a 4-day period resulted in an enhanced memory formation than 10 CS-US repeated pairings over a 2-day period or 20 CS-US repeated pairings on a single day. Backward conditioning (US-CS pairings did not result in conditioning. Thus, this taste avoidance conditioning was CS-US pairing specific. Food avoidance behavior was not observed following training, however, if snails were immediately subjected to a cold-block (4°C for 10 min. It was critical that the cold-block be applied within 10 min to block long-term memory (LTM formation. Further, exposure to the cold-block 180 min after training also blocked both STM and LTM formation. The effects of the cold-block on subsequent learning and memory formation were also examined. We found no long lasting effects of the cold-block on subsequent memory formation. If protein kinase C was activated before the conditioning paradigm, snails could still acquire STM despite exposure to the cold-block.

  1. Rouse modes of self-avoiding flexible polymers

    OpenAIRE

    Panja, D.; Barkema, G. T.

    2009-01-01

    Using a lattice-based Monte Carlo code for simulating self-avoiding flexible polymers in three dimensions in the absence of explicit hydrodynamics, we study their Rouse modes. For self-avoiding polymers, the Rouse modes are not expected to be statistically independent; nevertheless, we demonstrate that numerically these modes maintain a high degree of statistical independence. Based on high-precision simulation data we put forward an approximate analytical expression for the mode amplitude co...

  2. Avoidance from petroleum hydrocarbons by the cod (Gadus morhua)

    OpenAIRE

    Bøhle, Bjørn

    1982-01-01

    In laboratory experiments cod was presented a choice situation between different concentrations of petroleum hydrocarbons, appearing as "water soluble fraction" and emulsified droplets derived from Fuel Oil No. 2. In most experiments, the fishes seemed to avoid water containing hydrocarbons, though some fishes for periods was indifferent also to considerable contaminated water. The over all results indicates that a majority of the fishes avoided water containing total hyd...

  3. Autonomous Visual Navigation and Laser-based Moving Obstacle Avoidance

    OpenAIRE

    Cherubini, Andrea; Spindler, Fabien; Chaumette, François

    2014-01-01

    International audience Moving obstacle avoidance is a fundamental re- quirement for any robot operating in real environments, where pedestrians, bicycles and cars are present. In this paper, we propose and validate a framework for avoiding moving obstacles during visual navigation with a wheeled mobile robot. Visual navigation consists of following a path, represented as an ordered set of key images, which have been acquired by an on-board camera in a teaching phase. While following such p...

  4. A bijection to count (1-23-4)-avoiding permutations

    OpenAIRE

    Callan, David

    2010-01-01

    A permutation is (1-23-4)-avoiding if it contains no four entries, increasing left to right, with the middle two adjacent in the permutation. Here we give a 2-variable recurrence for the number of such permutations, improving on the previously known 4-variable recurrence. At the heart of the proof is a bijection from (1-23-4)-avoiding permutations to increasing ordered trees whose leaves, taken in preorder, are also increasing.

  5. Amygdala involvement in human avoidance, escape and approach behavior

    OpenAIRE

    Schlund, Michael W.; Cataldo, Michael F

    2010-01-01

    Many forms of psychopathology and substance abuse problems are characterized by chronic ritualized forms of avoidance and escape behavior that are designed to control or modify external or internal (i.e, thoughts, emotions, bodily sensations) threats. In this functional magnetic resonance imaging investigation, we examined amygdala reactivity to threatening cues when avoidance responding consistently prevented contact with an upcoming aversive event (money loss). In addition, we examined esca...

  6. Identity brand avoidance: How is it manifested in social media?

    OpenAIRE

    CHAN KAO CHUNG, Cindy

    2011-01-01

    Existing research on brand symbolic consumption mainly focuses on brand approach; the phenomenon being explained by the theory of self congruity, i.e. consumers would approach brands whose image is congruent to their actual or ideal self. On the other hand, identity brand avoidance, has been object of less attention. The scarce research dedicated to this field essentially revolves around the causes of identity brand avoidance, i.e. when consumers have a positive image of themselves and a nega...

  7. Impact of Tactical and Strategic Weather Avoidance on Separation Assurance

    Science.gov (United States)

    Refai, Mohamad S.; Windhorst, Robert

    2011-01-01

    The ability to keep flights away from weather hazards while maintaining aircraft-to-aircraft separation is critically important. The Advanced Airspace Concept is an automation concept that implements a ground-based strategic conflict resolution algorithm for management of aircraft separation. The impact of dynamic and uncertain weather avoidance on this concept is investigated. A strategic weather rerouting system is integrated with the Advanced Airspace Concept, which also provides a tactical weather avoidance algorithm, in a fast time simulation of the Air Transportation System. Strategic weather rerouting is used to plan routes around weather in the 20 minute to two-hour time horizon. To address forecast uncertainty, flight routes are revised at 15 minute intervals. Tactical weather avoidance is used for short term trajectory adjustments (30 minute planning horizon) that are updated every minute to address any weather conflicts (instances where aircraft are predicted to pass through weather cells) that are left unresolved by strategic weather rerouting. The fast time simulation is used to assess the impact of tactical weather avoidance on the performance of automated conflict resolution as well as the impact of strategic weather rerouting on both conflict resolution and tactical weather avoidance. The results demonstrate that both tactical weather avoidance and strategic weather rerouting increase the algorithm complexity required to find aircraft conflict resolutions. Results also demonstrate that tactical weather avoidance is prone to higher airborne delay than strategic weather rerouting. Adding strategic weather rerouting to tactical weather avoidance reduces total airborne delays for the reported scenario by 18% and reduces the number of remaining weather violations by 13%. Finally, two features are identified that have proven important for strategic weather rerouting to realize these benefits; namely, the ability to revise reroutes and the use of maneuvers

  8. Learning Networks, Networked Learning

    NARCIS (Netherlands)

    Sloep, Peter; Berlanga, Adriana

    2010-01-01

    Sloep, P. B., & Berlanga, A. J. (2011). Learning Networks, Networked Learning [Redes de Aprendizaje, Aprendizaje en Red]. Comunicar, XIX(37), 55-63. Retrieved from http://dx.doi.org/10.3916/C37-2011-02-05

  9. Learning Networks, Networked Learning

    NARCIS (Netherlands)

    Sloep, Peter

    2011-01-01

    Sloep, P. B. (2011). Learning Networks, Networked Learning. Presentation at Annual Assembly of the European Society for the Systemic Innovation of Education - ESSIE. May, 27, 2011, Leuven, Belgium: Open University in the Netherlands.

  10. Avoiding Colored Partitions of Lengths Two and Three

    CERN Document Server

    Goyt, Adam M

    2011-01-01

    Pattern avoidance in the symmetric group $S_n$ has provided a number of useful connections between seemingly unrelated problems from stack-sorting to Schubert varieties. Recent work has generalized these results to $S_n\\wr C_c$, the objects of which can be viewed as "colored permutations". Another body of research that has grown from the study of pattern avoidance in permutations is pattern avoidance in $\\Pi_n$, the set of set partitions of $[n]$. Pattern avoidance in set partitions is a generalization of the well-studied notion of noncrossing partitions. Motivated by recent results in pattern avoidance in $S_n \\wr C_c$ we provide a catalog of initial results for pattern avoidance in colored partitions, $\\Pi_n \\wr C_c$. We note that colored set partitions are not a completely new concept. \\emph{Signed} (2-colored) set partitions appear in the work of Bj\\"{o}rner and Wachs involving the homology of partition lattices. However, we seek to study these objects in a new enumerative context.

  11. Global and local obstacle avoidance technique for an autonomous vehicle

    Science.gov (United States)

    Gray, Keith W.; Saunders, Kevin S.

    1999-07-01

    The Center for Self-Organizing and Intelligent Systems (CSOIS) is engaged in developing autonomous ground vehicles. A significant problem for such vehicles is obstacle detection and avoidance. After studying various methods of detection, a scanning laser system was chosen that can detect objects at a distance of up to thirty feet while traveling between five and ten miles per hour. Once an object is detected, the vehicle must avoid it. The project employs a mission-level path planner that predetermines the path of a vehicle. One avoidance scheme is to inform the path planner of the obstacle and then let it re-plan the path. This is the global approach to the problem, which allows the use of existing software for maneuvering the vehicle. However, replanning is time consuming and lacks knowledge of the entire obstacle. An alternative approach is to use local avoidance, whereby a vehicle determines how to get by an obstacle without help from the path planner. This approach offers faster response without requiring the computing resource of the path planner. The disadvantage is that during local avoidance the vehicle ignores the global map of known obstacles and does not know to turn control back to the path planner if mission efficiency is adversely affected. This paper will describe a method for combining the current global path planner with a local obstacle avoidance technique to efficiently complete required tasks in a partially unknown environment.

  12. Slow maturation of planning in obstacle avoidance in humans.

    Science.gov (United States)

    Corporaal, Sharissa H A; Swinnen, Stephan P; Duysens, Jacques; Bruijn, Sjoerd M

    2016-01-01

    Complex gait (e.g., obstacle avoidance) requires a higher cognitive load than simple steady-state gait, which is a more automated movement. The higher levels of the central nervous system, responsible for adjusting motor plans to complex gait, develop throughout childhood into adulthood. Therefore, we hypothesize that gait strategies in complex gait are likely to mature until adulthood as well. However, little is known about the maturation of complex gait from childhood into adolescence and adulthood. To address this issue, we investigated obstacle avoidance in forty-four 8- to 18-yr-old participants who walked at preferred speed along a 6-m walkway on which a planar obstacle (150% of step length, 1 m wide) was projected. Participants avoided the obstacle by stepping over this projection, while lower body kinematics were recorded. Results showed that step length and speed adjustments during successful obstacle avoidance were similar across all ages, even though younger children modified step width to a greater extent. Additionally, the younger children used larger maximal toe elevations and take-off distances than older children. Moreover, during unsuccessful trials, younger children deployed exaggerated take-off distances, which resulted in obstacle contact upon the consecutive heel strike. These results indicate that obstacle avoidance is not fully matured in younger children, and that the inability to plan precise foot placements is an important factor contributing to failures in obstacle avoidance.

  13. Attachment avoidance predicts inflammatory responses to marital conflict.

    Science.gov (United States)

    Gouin, Jean-Philippe; Glaser, Ronald; Loving, Timothy J; Malarkey, William B; Stowell, Jeffrey; Houts, Carrie; Kiecolt-Glaser, Janice K

    2009-10-01

    Marital stress has been associated with immune dysregulation, including increased production of interleukin-6 (IL-6). Attachment style, one's expectations about the availability and responsiveness of others in intimate relationships, appears to influence physiological stress reactivity and thus could influence inflammatory responses to marital conflict. Thirty-five couples were invited for two 24-h admissions to a hospital research unit. The first visit included a structured social support interaction, while the second visit comprised the discussion of a marital disagreement. A mixed effect within-subject repeated measure model indicated that attachment avoidance significantly influenced IL-6 production during the conflict visit but not during the social support visit. Individuals with higher attachment avoidance had on average an 11% increase in total IL-6 production during the conflict visit as compared to the social support visit, while individuals with lower attachment avoidance had, on average, a 6% decrease in IL-6 production during the conflict visit as compared to the social support visit. Furthermore, greater attachment avoidance was associated with a higher frequency of negative behaviors and a lower frequency of positive behaviors during the marital interaction, providing a mechanism by which attachment avoidance may influence inflammatory responses to marital conflict. In sum, these results suggest that attachment avoidance modulates marital behavior and stress-induced immune dysregulation. PMID:18952163

  14. Approach, avoidance, and affect: A meta-analysis of approach-avoidance tendencies in manual reaction time tasks

    Directory of Open Access Journals (Sweden)

    Hans ePhaf

    2014-05-01

    Full Text Available Approach action tendencies towards positive stimuli and avoidance tendencies from negative stimuli are widely seen to foster survival. Many studies have shown that approach and avoidance arm movements are facilitated by positive and negative affect, respectively. There is considerable debate whether positively and negatively valenced stimuli prime approach and avoidance movements directly (i.e., immediate, unintentional, implicit, automatic, and stimulus-based, or indirectly (i.e., after conscious or nonconscious interpretation of the situation. The direction and size of these effects were often found to depend on the instructions referring to the stimulus object or the self, and on explicit vs. implicit stimulus evaluation. We present a meta-analysis of 29 studies included for their use of strongly positive and negative stimuli, with 81 effect sizes derived solely from the means and standard deviations (combined N = 1538, to examine the automaticity of the link between affective information processing and approach and avoidance, and to test whether it depends on instruction, type of approach-avoidance task, and stimulus type. Results show a significant small to medium-sized effect after correction for publication bias. The strongest arguments for an indirect link between affect and approach-avoidance were the absence of evidence for an effect with implicit evaluation, and the opposite directions of the effect with self and object-related interpretations. The link appears to be influenced by conscious or nonconscious intentions to deal with affective stimuli.

  15. Java Architecture for Detect and Avoid Extensibility and Modeling

    Science.gov (United States)

    Santiago, Confesor; Mueller, Eric Richard; Johnson, Marcus A.; Abramson, Michael; Snow, James William

    2015-01-01

    Unmanned aircraft will equip with a detect-and-avoid (DAA) system that enables them to comply with the requirement to "see and avoid" other aircraft, an important layer in the overall set of procedural, strategic and tactical separation methods designed to prevent mid-air collisions. This paper describes a capability called Java Architecture for Detect and Avoid Extensibility and Modeling (JADEM), developed to prototype and help evaluate various DAA technological requirements by providing a flexible and extensible software platform that models all major detect-and-avoid functions. Figure 1 illustrates JADEM's architecture. The surveillance module can be actual equipment on the unmanned aircraft or simulators that model the process by which sensors on-board detect other aircraft and provide track data to the traffic display. The track evaluation function evaluates each detected aircraft and decides whether to provide an alert to the pilot and its severity. Guidance is a combination of intruder track information, alerting, and avoidance/advisory algorithms behind the tools shown on the traffic display to aid the pilot in determining a maneuver to avoid a loss of well clear. All these functions are designed with a common interface and configurable implementation, which is critical in exploring DAA requirements. To date, JADEM has been utilized in three computer simulations of the National Airspace System, three pilot-in-the-loop experiments using a total of 37 professional UAS pilots, and two flight tests using NASA's Predator-B unmanned aircraft, named Ikhana. The data collected has directly informed the quantitative separation standard for "well clear", safety case, requirements development, and the operational environment for the DAA minimum operational performance standards. This work was performed by the Separation Assurance/Sense and Avoid Interoperability team under NASA's UAS Integration in the NAS project.

  16. Different Futures of Adaptive Collaborative Learning Support

    Science.gov (United States)

    Rummel, Nikol; Walker, Erin; Aleven, Vincent

    2016-01-01

    In this position paper we contrast a Dystopian view of the future of adaptive collaborative learning support (ACLS) with a Utopian scenario that--due to better-designed technology, grounded in research--avoids the pitfalls of the Dystopian version and paints a positive picture of the practice of computer-supported collaborative learning 25 years…

  17. Improving Open Access through Prior Learning Assessment

    Science.gov (United States)

    Yin, Shuangxu; Kawachi, Paul

    2013-01-01

    This paper explores and presents new data on how to improve open access in distance education through using prior learning assessments. Broadly there are three types of prior learning assessment (PLAR): Type-1 for prospective students to be allowed to register for a course; Type-2 for current students to avoid duplicating work-load to gain…

  18. Test anxiety and performance-avoidance goals explain gender differences in SAT-V, SAT-M, and overall SAT scores.

    Science.gov (United States)

    Hannon, Brenda

    2012-11-01

    This study uses analysis of co-variance in order to determine which cognitive/learning (working memory, knowledge integration, epistemic belief of learning) or social/personality factors (test anxiety, performance-avoidance goals) might account for gender differences in SAT-V, SAT-M, and overall SAT scores. The results revealed that none of the cognitive/learning factors accounted for gender differences in SAT performance. However, the social/personality factors of test anxiety and performance-avoidance goals each separately accounted for all of the significant gender differences in SAT-V, SAT-M, and overall SAT performance. Furthermore, when the influences of both of these factors were statistically removed simultaneously, all non-significant gender differences reduced further to become trivial by Cohen's (1988) standards. Taken as a whole, these results suggest that gender differences in SAT-V, SAT-M, and overall SAT performance are a consequence of social/learning factors. PMID:23997382

  19. Experimental characterization of collision avoidance in pedestrian dynamics

    Science.gov (United States)

    Parisi, Daniel R.; Negri, Pablo A.; Bruno, Luciana

    2016-08-01

    In the present paper, the avoidance behavior of pedestrians was characterized by controlled experiments. Several conflict situations were studied considering different flow rates and group sizes in crossing and head-on configurations. Pedestrians were recorded from above, and individual two-dimensional trajectories of their displacement were recovered after image processing. Lateral swaying amplitude and step lengths were measured for free pedestrians, obtaining similar values to the ones reported in the literature. Minimum avoidance distances were computed in two-pedestrian experiments. In the case of one pedestrian dodging an arrested one, the avoidance distance did not depend on the relative orientation of the still pedestrian with respect to the direction of motion of the first. When both pedestrians were moving, the avoidance distance in a perpendicular encounter was longer than the one obtained during a head-on approach. It was found that the mean curvature of the trajectories was linearly anticorrelated with the mean speed. Furthermore, two common avoidance maneuvers, stopping and steering, were defined from the analysis of the acceleration and curvature in single trajectories. Interestingly, it was more probable to observe steering events than stopping ones, also the probability of simultaneous steering and stopping occurrences was negligible. The results obtained in this paper can be used to validate and calibrate pedestrian dynamics models.

  20. The mnemonic mover: nostalgia regulates avoidance and approach motivation.

    Science.gov (United States)

    Stephan, Elena; Wildschut, Tim; Sedikides, Constantine; Zhou, Xinyue; He, Wuming; Routledge, Clay; Cheung, Wing-Yee; Vingerhoets, Ad J J M

    2014-06-01

    In light of its role in maintaining psychological equanimity, we proposed that nostalgia--a self-relevant, social, and predominantly positive emotion--regulates avoidance and approach motivation. We advanced a model in which (a) avoidance motivation triggers nostalgia and (b) nostalgia, in turn, increases approach motivation. As a result, nostalgia counteracts the negative impact of avoidance motivation on approach motivation. Five methodologically diverse studies supported this regulatory model. Study 1 used a cross-sectional design and showed that avoidance motivation was positively associated with nostalgia. Nostalgia, in turn, was positively associated with approach motivation. In Study 2, an experimental induction of avoidance motivation increased nostalgia. Nostalgia then predicted increased approach motivation. Studies 3-5 tested the causal effect of nostalgia on approach motivation and behavior. These studies demonstrated that experimental nostalgia inductions strengthened approach motivation (Study 3) and approach behavior as manifested in reduced seating distance (Study 4) and increased helping (Study 5). The findings shed light on nostalgia's role in regulating the human motivation system.

  1. The mnemonic mover: nostalgia regulates avoidance and approach motivation.

    Science.gov (United States)

    Stephan, Elena; Wildschut, Tim; Sedikides, Constantine; Zhou, Xinyue; He, Wuming; Routledge, Clay; Cheung, Wing-Yee; Vingerhoets, Ad J J M

    2014-06-01

    In light of its role in maintaining psychological equanimity, we proposed that nostalgia--a self-relevant, social, and predominantly positive emotion--regulates avoidance and approach motivation. We advanced a model in which (a) avoidance motivation triggers nostalgia and (b) nostalgia, in turn, increases approach motivation. As a result, nostalgia counteracts the negative impact of avoidance motivation on approach motivation. Five methodologically diverse studies supported this regulatory model. Study 1 used a cross-sectional design and showed that avoidance motivation was positively associated with nostalgia. Nostalgia, in turn, was positively associated with approach motivation. In Study 2, an experimental induction of avoidance motivation increased nostalgia. Nostalgia then predicted increased approach motivation. Studies 3-5 tested the causal effect of nostalgia on approach motivation and behavior. These studies demonstrated that experimental nostalgia inductions strengthened approach motivation (Study 3) and approach behavior as manifested in reduced seating distance (Study 4) and increased helping (Study 5). The findings shed light on nostalgia's role in regulating the human motivation system. PMID:24708500

  2. Animal models of social avoidance and social fear.

    Science.gov (United States)

    Toth, Iulia; Neumann, Inga D

    2013-10-01

    Social fear and avoidance of social situations represent the main behavioral symptoms of social anxiety disorder (SAD), a highly prevalent anxiety disorder that is poorly elucidated and has rather unsatisfactory therapeutic options. Therefore, animal models are needed to study the underlying etiology and pathophysiology of SAD and to verify the efficacy of possible novel treatment approaches. In this review, we describe and discuss the most important paradigms that have been shown to induce social avoidance and fear in rodents, including foot shock exposure, restraint stress, social isolation, social instability, social defeat, conditioned defeat, social defeat/overcrowding, chronic subordinate colony housing, chronic mild stress, maternal separation and social fear conditioning. We also describe some of the behavioral paradigms used to assess social avoidance and fear in rodents, including the social interaction test, the social preference-avoidance test, the social approach-avoidance test, the three-chambered social approach test, the partition test and the modified Y-maze test. We focus on the behavioral alterations these paradigms induce, especially on social interaction, general anxiety and depressive-like behavior given that SAD is strongly comorbid with anxiety and affective disorders.

  3. Sense and avoid technology for Global Hawk and Predator UAVs

    Science.gov (United States)

    McCalmont, John F.; Utt, James; Deschenes, Michael; Taylor, Michael J.

    2005-05-01

    The Sensors Directorate at the Air Force Research Laboratory (AFRL) along with Defense Research Associates, Inc. (DRA) conducted a flight demonstration of technology that could potentially satisfy the Federal Aviation Administration's (FAA) requirement for Unmanned Aerial Vehicles (UAVs) to sense and avoid local air traffic sufficient to provide an "...equivalent level of safety, comparable to see-and-avoid requirements for manned aircraft". This FAA requirement must be satisfied for autonomous UAV operation within the national airspace. The real-time on-board system passively detects approaching aircraft, both cooperative and non-cooperative, using imaging sensors operating in the visible/near infrared band and a passive moving target indicator algorithm. Detection range requirements for RQ-4 and MQ-9 UAVs were determined based on analysis of flight geometries, avoidance maneuver timelines, system latencies and human pilot performance. Flight data and UAV operating parameters were provided by the system program offices, prime contractors, and flight-test personnel. Flight demonstrations were conducted using a surrogate UAV (Aero Commander) and an intruder aircraft (Beech Bonanza). The system demonstrated target detection ranges out to 3 nautical miles in nose-to-nose scenarios and marginal visual meteorological conditions. (VMC) This paper will describe the sense and avoid requirements definition process and the system concept (sensors, algorithms, processor, and flight rest results) that has demonstrated the potential to satisfy the FAA sense and avoid requirements.

  4. The neuroscience of learning.

    Science.gov (United States)

    Collins, John W

    2007-10-01

    Significant advances have been made in understanding the neurophysiological basis of learning, including the discovery of mirror neurons and the role of cyclic adenosine monophosphate (cAMP) responsive element binding (CREB) protein in learning. Mirror neurons help us visually compare an observed activity with a remembered action in our memory, an ability that helps us imitate and learn through watching. Long-term potentiation, the Hebb rule, and CREB protein are associated with the formation of long-term memories. Conversely, protein phosphatase 1 and glucocorticoids are neurophysiological phenomena that limit what can be learned and cause forgetfulness. Gardner's theory of multiple intelligences contends that different areas of the brain are responsible for different competencies that we all possess to varying degrees. These multiple intelligences can be used as strategies for improved learning. Repeating material, using mnemonics, and avoiding overwhelming stress are other strategies for improving learning. Imaging studies have shown that practice with resultant learning results in significantly less use of brain areas, indicating that the brain becomes more efficient. Experts have advantages over novices, including increased cognitive processing efficiency. Nurses are in a unique position to use their understanding of neurophysiological principles to implement better educational strategies to provide quality education to patients and others.

  5. The neuroscience of learning.

    Science.gov (United States)

    Collins, John W

    2007-10-01

    Significant advances have been made in understanding the neurophysiological basis of learning, including the discovery of mirror neurons and the role of cyclic adenosine monophosphate (cAMP) responsive element binding (CREB) protein in learning. Mirror neurons help us visually compare an observed activity with a remembered action in our memory, an ability that helps us imitate and learn through watching. Long-term potentiation, the Hebb rule, and CREB protein are associated with the formation of long-term memories. Conversely, protein phosphatase 1 and glucocorticoids are neurophysiological phenomena that limit what can be learned and cause forgetfulness. Gardner's theory of multiple intelligences contends that different areas of the brain are responsible for different competencies that we all possess to varying degrees. These multiple intelligences can be used as strategies for improved learning. Repeating material, using mnemonics, and avoiding overwhelming stress are other strategies for improving learning. Imaging studies have shown that practice with resultant learning results in significantly less use of brain areas, indicating that the brain becomes more efficient. Experts have advantages over novices, including increased cognitive processing efficiency. Nurses are in a unique position to use their understanding of neurophysiological principles to implement better educational strategies to provide quality education to patients and others. PMID:17966298

  6. Effect of gabapentin on haloperidol induced inhibition of conditioned avoidance response in rat

    Directory of Open Access Journals (Sweden)

    Nishant B. Bhansali

    2012-06-01

    Full Text Available Background: Haloperidol, an antipsychotic adversely affects acquisition and retention of a learned task. We decided to test the effect of Gabapentin, a new anti-epileptic drug using conditioned avoidance response model with cook’s pole climbing apparatus and haloperidol. Methods: Four groups of six rats were taken for this purpose. All the rats were first given drugs for five days and then trained for a period of 15 days. Gabapentin was given in a dose of 100mg/kg intra peritoneal, while haloperidol was given 0.5mg/kg intra peritoneal. Results: At the end of the training duration rats in the vehicle and gabapentin treated group achieved ≥85% acquisition responses. While the haloperidol and haloperidol + gabapentin group did not achieve the desired percentage of learning. A learning curve was plotted by using the percentage of conditioned responses in each group versus number of days. The mean ± SD percentage of conditioned responses of day 14 and 15 were for haloperidol group 26.19 ±11.90, for vehicle group 86.90 ± 4.29, for the gabapentin treated group 95.24 ± 2.38 and for the gabapentin + haloperidol group 46.42 ± 12.20. These figures and the learning curve suggest that gabapentin treated rats had a better acquisition response and haloperidol depressed learning. Conclusions: At the end of study duration we found that gabapentin significantly improved the acquisition response than the vehicle control group. Also haloperidol depressed the acquisition response. Gabapentin did not lead to reversal of haloperidol induced depression of acquisition process. [Int J Basic Clin Pharmacol 2012; 1(3.000: 216-220

  7. Incest avoidance: oedipal and preoedipal, natural and cultural.

    Science.gov (United States)

    Paul, Robert A

    2010-12-01

    Why do most people experience a subjective aversion to the idea of incestuous sexual relations? To help answer this question, recent strands of thinking in both cultural and evolutionary anthropology are considered together with psychoanalytic theories regarding incest avoidance. Coevolutionary theories that propose ways to think about genetic and cultural inheritance as partially independent of each other, evolutionary arguments about the reproductive advantages of incest avoidance, structuralist theory arguing for a kind of incest aversion unrelated to any possible Darwinian selective advantage, and other trends in biosocial research into the origins of the incest avoidance are considered. Finally, a synthesis is proposed that seeks to expand our understanding of the oedipal and preoedipal dynamics of the aversion as these are conceptualized in psychoanalytic theory.

  8. YUCCA auxin biosynthetic genes are required for Arabidopsis shade avoidance

    Science.gov (United States)

    Müller-Moulé, Patricia; Nozue, Kazunari; Pytlak, Melissa L.; Palmer, Christine M.; Covington, Michael F.; Wallace, Andreah D.; Harmer, Stacey L.

    2016-01-01

    Plants respond to neighbor shade by increasing stem and petiole elongation. Shade, sensed by phytochrome photoreceptors, causes stabilization of PHYTOCHROME INTERACTING FACTOR proteins and subsequent induction of YUCCA auxin biosynthetic genes. To investigate the role of YUCCA genes in phytochrome-mediated elongation, we examined auxin signaling kinetics after an end-of-day far-red (EOD-FR) light treatment, and found that an auxin responsive reporter is rapidly induced within 2 hours of far-red exposure. YUCCA2, 5, 8, and 9 are all induced with similar kinetics suggesting that they could act redundantly to control shade-mediated elongation. To test this hypothesis we constructed a yucca2, 5, 8, 9 quadruple mutant and found that the hypocotyl and petiole EOD-FR and shade avoidance responses are completely disrupted. This work shows that YUCCA auxin biosynthetic genes are essential for detectable shade avoidance and that YUCCA genes are important for petiole shade avoidance. PMID:27761349

  9. Dynamic Obstacle Avoidance for an Omnidirectional Mobile Robot

    Directory of Open Access Journals (Sweden)

    Robert L. Williams

    2010-01-01

    Full Text Available We have established a novel method of obstacle-avoidance motion planning for mobile robots in dynamic environments, wherein the obstacles are moving with general velocities and accelerations, and their motion profiles are not preknown. A hybrid system is presented in which a global deliberate approach is applied to determine the motion in the desired path line (DPL, and a local reactive approach is used for moving obstacle avoidance. A machine vision system is required to sense obstacle motion. Through theoretical analysis, simulation, and experimental validation applied to the Ohio University RoboCup robot, we show the method is effective to avoid collisions with moving obstacles in a dynamic environment.

  10. The Effect of Tax Rates on Fiscal Evasion and Avoidance

    Directory of Open Access Journals (Sweden)

    Mentor Gashi

    2016-02-01

    Full Text Available Abstract:In order to findelements that destimulate fiscal evasion or avoidance, we have submitted six elements, through the questionnaire, to determine which elements are that destimulate the fiscal evasion and avoidance, and evaluate their impact.This paper is focused in customs duty avoidance.The elements that we have submitted to evaluate their power, are: Powerful control during customs clearance, more efficient post clearance control, probability of subject investigation, higher fines, lower tax rate, consciousness of companies.In this research, we collected 248 answers, and can present these results:Fiscal policy or lower tax rate is a powerful element that can't stimulate a tax evasion and/or avoidance, for this element we received 68 answers from respondentsor 27.42%. The other element is powerful control from customs during clearance, for this element we received 52 answers from respondents or 20.97%. The next element following is consciousness of companies, for this element are 36 answers from respondents or 12.90%. The next element investigation are 33 answers or 12.90%, post clearance control are 31 respondents or 12%, the last element is higher fines, that are 28 respondents or 11.29%.As presented, all the elements are very close to each other, except first and second element, which are: lower tax rate and powerful control from customs during clearance. These elements have more effect, that destimulate tax evasion and avoidance.  Keywords: tax rates, fiscal evasion, fiscal avoidance, elements of destimulate.

  11. On (cosmological) singularity avoidance in loop quantum gravity

    Energy Technology Data Exchange (ETDEWEB)

    Brunnemann, J; Thiemann, T [MPI fuer Gravitationsphysik, Albert-Einstein-Institut, Am Muehlenberg 1, 14476 Potsdam (Germany); Perimeter Institute for Theoretical Physics, 31 Caroline Street N, Waterloo, ON N2L 2Y5 (Canada)

    2006-03-07

    Loop quantum cosmology (LQC), mainly due to Bojowald, is not the cosmological sector of loop quantum gravity (LQG). Rather, LQC consists of a truncation of the phase space of classical general relativity to spatially homogeneous situations which is then quantized by the methods of LQG. Thus, LQC is a quantum-mechanical toy model (finite number of degrees of freedom) for LQG (a genuine QFT with an infinite number of degrees of freedom) which provides important consistency checks. However, it is a non-trivial question whether the predictions of LQC are robust after switching on the inhomogeneous fluctuations present in full LQG. Two of the most spectacular findings of LQC are that: (1) the inverse scale factor is bounded from above on zero-volume eigenstates which hints at the avoidance of the local curvature singularity and (2) the quantum Einstein equations are non-singular which hints at the avoidance of the global initial singularity. This rests on (1) a key technique developed for LQG and (2) the fact that there are no inhomogeneous excitations. We display the result of a calculation for LQG which proves that the (analogon of the) inverse scale factor, while densely defined, is not bounded from above on zero-volume eigenstates. Thus, in full LQG, if curvature singularity avoidance is realized, then not in this simple way. In fact, it turns out that the boundedness of the inverse scale factor is neither necessary nor sufficient for the curvature singularity avoidance and that non-singular evolution equations are neither necessary nor sufficient for initial singularity avoidance because none of these criteria are formulated in terms of observable quantities. After outlining what would be required, we present the results of a calculation for LQG which could be a first indication that our criteria at least for curvature singularity avoidance are satisfied in LQG.

  12. Formation and obstacle avoidance control for multiagent systems

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    This paper considers the problems of formation and obstacle avoidance for multiagent systems.The objective is to design a term of agents that can reach a desired formation while avoiding collision with obstacles.To reduce the amount of information interaction between agents and target,we adopt the leader-follower formation strategy.By using the receding horizon control (RHC),an optimal problem is formulated in terms of cost minimization under constraints.Information on obstacles is incorporated online as se...

  13. Managed care contracting and payment reform: avoiding a showdown.

    Science.gov (United States)

    Nugent, Michael E

    2010-07-01

    Health reform promises to fundamentally change what and how CMS and commercial payers reimburse providers. Providers need to transition from their traditionally adversarial, transactions-based payer relationships to ones that optimize purchaser and patient value for the dollar. To avoid negotiation table showdowns and to prepare for reform, commercial payers and providers should take three actions: Recognize the dead ends with their historical relationships. Formulate their road map to value-based contracting. Avoid operational pot-holes along the way. PMID:20608414

  14. OBSTACLE-AVOIDANCE NAVIGATION OF MULTIPLE MOBILE ROBOTS

    Institute of Scientific and Technical Information of China (English)

    罗青; 李智军; 吕恬生

    2002-01-01

    In the context of robot soccer, the robots have to select actions to achieve individual and team goals in the dynamic environment. It is important for a robot to acquire navigation behaviors for avoiding other robots and obstacles in the real-time environment. This paper suggested an efficient approach to collision-avoidance in multirobot system. This approach is based on velocity information of moving objects and the distance between robot and obstacle in three specified directions. The main contribution of this paper is that it provides a method for robots with decreased-computational cost and makes the robot navigate without collision with each other in a complicated environment.

  15. Learning Disabilities

    Science.gov (United States)

    ... How Can I Help a Friend Who Cuts? Learning Disabilities KidsHealth > For Teens > Learning Disabilities Print A ... study engineering as he'd hoped? What Are Learning Disabilities? For someone diagnosed with a learning disability, ...

  16. Acquisition and extinction of operant pain-related avoidance behavior using a 3 degrees-of-freedom robotic arm.

    Science.gov (United States)

    Meulders, Ann; Franssen, Mathijs; Fonteyne, Riet; Vlaeyen, Johan W S

    2016-05-01

    Ample empirical evidence endorses the role of associative learning in pain-related fear acquisition. Nevertheless, research typically focused on self-reported and psychophysiological measures of fear. Avoidance, which is overt behavior preventing the occurrence of an aversive (painful) stimulus, has been largely neglected so far. Therefore, we aimed to fill this gap and developed an operant conditioning procedure for pain-related avoidance behavior. Participants moved their arm to a target location using the HapticMaster (FCS Robotics; Moog Inc, East Aurora, New York), a 3 degrees-of-freedom, force-controlled robotic arm. Three movement trajectories led to the target location. If participants in the Experimental Group took the shortest/easiest trajectory, they always received a painful stimulus (T1 = 100% reinforcement; no resistance). If they deviated from this trajectory, the painful stimulus could be partly or totally prevented (T2 = 50% reinforcement; T3 = 0% reinforcement), but more effort was needed (T2 = moderate resistance and deviation; T3 = strongest resistance and largest deviation). The Yoked Group received the same reinforcement schedule irrespective of their own behavior. During the subsequent extinction phase, no painful stimuli were delivered. Self-reported pain-expectancy and pain-related fear were assessed, and avoidance behavior was operationalized as the maximal distance from the shortest trajectory. During acquisition, the Experimental Group reported more pain-related fear and pain-expectancy to T1 vs T2 vs T3 and deviated more from the shortest trajectory than the Yoked Group. During subsequent extinction, avoidance behavior, self-reported fear, and pain-expectancy decreased significantly, but conditioned differences persisted despite the absence of painful stimuli. To conclude, this operant learning task might provide a valid paradigm to study pain-related avoidance behavior in future studies. PMID:26761388

  17. All About PID - Testing and Avoidance in the Field

    Energy Technology Data Exchange (ETDEWEB)

    Hacke, Peter; Johnston, Steve

    2016-09-01

    Potential-induced degradation can cause significant power loss in modules if the appropriate precautions are not taken. In the first part of a new series in PV Tech Power on module failure, Peter Hacke and Steve Johnston assess the current state-of-the-art in detecting, avoiding and mitigating the worst effects of PID.

  18. Improving Network Performance using ACO Based Redundant Link Avoidance Algorithm

    Directory of Open Access Journals (Sweden)

    B. Chandra Mohan

    2010-05-01

    Full Text Available In the wide spread internet, response time and pocket loss are inappropriate due to network traffic, as a result the network efficiency becomes worst and the system provides poor Quality of Service (QoS. An optimal routing protocol, especially multipath may avoid such traffic in the network. But existing routing protocols, both single path and multi path, concentrates only on finding the routes based on any one or some set of metrics, that not always suitable for dynamic, cloud natured network environment. Ant Colony Optimization (ACO based multipath routing protocol was suggested as an alternate to this problem by many researchers. The multipath ACO also provides same set of link(s for the source to destination, so that traffic merging again becomes a critical problem. This paper proposes an optimal solution to avoid the problem of traffic merging in the network by removing redundant link in the route. The Proposed algorithm, called 'Redundant Link Avoidance (RLA algorithm', is an ACO based multi path routing methodology, avoiding copious link in the suggested routes of ACO multipath protocol.

  19. Avoidance of moulds in living rooms; Schimmelpilze in Wohnraeumen vermeiden

    Energy Technology Data Exchange (ETDEWEB)

    Anda Gonzalez, Leticia de; Spitzner, Martin H.

    2011-07-01

    The contribution under consideration supplies valuable recommendations regarding the avoidance of a growth of mould fungi in living rooms. Information about a correct ventilation behaviour, a correct heating behaviour, a correct positioning of furniture, a correct attachment of wall coverings and measures of the user behaviour are given.

  20. Avoiding Childhood Obesity (A Cup of Health with CDC)

    Centers for Disease Control (CDC) Podcasts

    2013-01-31

    Maintaining a healthy weight in childhood can prevent many health-related problems later in life. In this podcast, Dr. Jackson Sekhobo discusses the importance of avoiding obesity in childhood.  Created: 1/31/2013 by MMWR.   Date Released: 1/31/2013.

  1. The "Eye Avoidance" Hypothesis of Autism Face Processing.

    Science.gov (United States)

    Tanaka, James W; Sung, Andrew

    2016-05-01

    Although a growing body of research indicates that children with autism spectrum disorder (ASD) exhibit selective deficits in their ability to recognize facial identities and expressions, the source of their face impairment is, as yet, undetermined. In this paper, we consider three possible accounts of the autism face deficit: (1) the holistic hypothesis, (2) the local perceptual bias hypothesis and (3) the eye avoidance hypothesis. A review of the literature indicates that contrary to the holistic hypothesis, there is little evidence to suggest that individuals with autism do perceive faces holistically. The local perceptual bias account also fails to explain the selective advantage that ASD individuals demonstrate for objects and their selective disadvantage for faces. The eye avoidance hypothesis provides a plausible explanation of face recognition deficits where individuals with ASD avoid the eye region because it is perceived as socially threatening. Direct eye contact elicits a increased physiological response as indicated by heightened skin conductance and amygdala activity. For individuals with autism, avoiding the eyes is an adaptive strategy, however, this approach interferes with the ability to process facial cues of identity, expressions and intentions, exacerbating the social challenges for persons with ASD. PMID:24150885

  2. Instructional Support Predicts Children's Task Avoidance in Kindergarten

    Science.gov (United States)

    Pakarinen, Eija; Kiuru, Noona; Lerkkanen, Marja-Kristiina; Poikkeus, Anna-Maija; Ahonen, Timo; Nurmi, Jari-Erik

    2011-01-01

    This study examined the role of observed classroom quality in children's task-avoidant behavior and math skills in kindergarten. To investigate this, 1268 children were tested twice on their math skills during their kindergarten year. Kindergarten teachers (N = 137) filled in questionnaires measuring their professional experience and also rated…

  3. Avoidance of low doses of naphthalene by Collembola

    Energy Technology Data Exchange (ETDEWEB)

    Boitaud, Laetitia [Museum National d' Histoire Naturelle, CNRS UMR 5176, 4 avenue du Petit-Chateau, 91800 Brunoy (France); Salmon, Sandrine [Museum National d' Histoire Naturelle, CNRS UMR 5176, 4 avenue du Petit-Chateau, 91800 Brunoy (France); Bourlette, Celine [Museum National d' Histoire Naturelle, CNRS UMR 5176, 4 avenue du Petit-Chateau, 91800 Brunoy (France); Ponge, Jean-Francois [Museum National d' Histoire Naturelle, CNRS UMR 5176, 4 avenue du Petit-Chateau, 91800 Brunoy (France)]. E-mail: jean-francois.ponge@wanadoo.fr

    2006-02-15

    The introduction of behavioural aspects of soil animals in ecological risk assessment would allow us to better assess soil quality, all the more if a range of animal populations are considered. We compared the avoidance behaviour of several strains of springtails (Arthropoda: Collembola) obtained from different soils. Naphthalene, a polycyclic aromatic hydrocarbon (PAH), widely represented in soils polluted with hydrocarbons, was tested in aqueous solutions on nine springtail species issuing from four sites. Fine quartz sand saturated with an aqueous solution of naphthalene was avoided by most of the tested species, avoidance being, however, detected down to a concentration of 0.030 mg L{sup -1}. Folsomia candida (Isotomidae) was shown to be relatively tolerant to pollutants compared to other Collembola such as Mesaphorura macrochaeta, Mesaphorura yosii (Onychiuridae), Parisotoma notabilis (Isotomidae) and Arrhopalites caecus (Arrhopalitidae). Differences between strains could not be explained by properties of the original soils. - PAH avoidance by soil springtails is species-specific and differs among populations of the same species.

  4. 49 CFR 1152.32 - Calculation of avoidable costs.

    Science.gov (United States)

    2010-10-01

    ... 11-61-91 Do. Materials 21-61-91 Do. Purchased services 41-61-91 Do. Other expenses 61-61-91 Do. Legal... 21-61-93 Do. Purchased services 41-61-93 Do. Other expenses 61-61-93 Do. Research and development... property tax methodology if it is claiming the local property tax as an avoidable cost of...

  5. Characterization of white mold disease avoidance in common bean

    Science.gov (United States)

    White mold, caused by Sclerotinia sclerotiorum, is a devastating fungal disease of common bean (Phaseolus vulgaris L.) worldwide. Physiological resistance and disease avoidance conferred by plant architecture-related traits contribute to white mold field resistance. Our objective was to further exam...

  6. Robot vision: obstacle-avoidance techniques for unmanned aerial vehicles

    NARCIS (Netherlands)

    Carloni, Raffaella; Lippiello, Vincenzo; D'auria, Massimo; Fumagalli, Matteo; Mersha, Abeje Y.; Stramigioli, Stefano; Sicilano, Bruno

    2013-01-01

    In this article, a vision-based technique for obstacle avoidance and target identification is combined with haptic feedback to develop a new teleoperated navigation system for underactuated aerial vehicles in unknown environments. A three-dimensional (3-D) map of the surrounding environment is built

  7. Time Pressure Undermines Performance More Under Avoidance Than Approach Motivation

    NARCIS (Netherlands)

    Roskes, Marieke; Elliot, Andrew J.; Nijstad, Bernard A.; De Dreu, Carsten K. W.

    2013-01-01

    Four experiments were designed to test the hypothesis that performance is particularly undermined by time pressure when people are avoidance motivated. The results supported this hypothesis across three different types of tasks, including those well suited and those ill suited to the type of informa

  8. Obstacle avoidance to elicit freezing of gait during treadmill walking.

    NARCIS (Netherlands)

    Snijders, A.H.; Weerdesteijn, V.G.M.; Hagen, Y.J.; Duysens, J.E.J.; Giladi, N.; Bloem, B.R.

    2010-01-01

    Freezing of gait (FOG) is a common and disabling feature of Parkinson's disease (PD). Detailed pathophysiological studies are hampered by the fact that FOG episodes are difficult to elicit in a gait laboratory. We evaluated whether the need to avoid sudden obstacles on a treadmill can provoke FOG. W

  9. Obstacle Avoidance in Groping Locomotion of a Humanoid Robot

    Directory of Open Access Journals (Sweden)

    Masahiro Ohka

    2008-11-01

    Full Text Available This paper describes the development of an autonomous obstacle-avoidance method that operates in conjunction with groping locomotion on the humanoid robot Bonten-Maru II. Present studies on groping locomotion consist of basic research in which humanoid robot recognizes its surroundings by touching and groping with its arm on the flat surface of a wall. The robot responds to the surroundings by performing corrections to its orientation and locomotion direction. During groping locomotion, however, the existence of obstacles within the correction area creates the possibility of collisions. The objective of this paper is to develop an autonomous method to avoid obstacles in the correction area by applying suitable algorithms to the humanoid robot's control system. In order to recognize its surroundings, six-axis force sensors were attached to both robotic arms as end effectors for force control. The proposed algorithm refers to the rotation angle of the humanoid robot's leg joints due to trajectory generation. The algorithm relates to the groping locomotion via the measured groping angle and motions of arms. Using Bonten-Maru II, groping experiments were conducted on a wall's surface to obtain wall orientation data. By employing these data, the humanoid robot performed the proposed method autonomously to avoid an obstacle present in the correction area. Results indicate that the humanoid robot can recognize the existence of an obstacle and avoid it by generating suitable trajectories in its legs.

  10. Career Barriers: How People Experience, Overcome, and Avoid Failure.

    Science.gov (United States)

    London, Manuel

    This book defines career barriers, considers how people react to them, and offers ways to overcome and prevent them. It is geared towards people experiencing career barriers; for students at the start of their careers; for seasoned employees wanting to avoid or be prepared to deal with career barriers; and for managers, human resource…

  11. Binge Eating and Weight Control: The Role of Experiential Avoidance

    Science.gov (United States)

    Lillis, Jason; Hayes, Steven C.; Levin, Michael E.

    2011-01-01

    Two thirds of the adults in the United States are overweight or obese. Binge eating is a barrier to treatment adherence and sustained weight loss, and can be seen as a form of experiential avoidance. The current study analyzed the impact of binge eating on weight reduction in a previously published study of a 1-day acceptance and commitment…

  12. Concept development of automatic guidance for rotorcraft obstacle avoidance

    Science.gov (United States)

    Cheng, Victor H. L.

    1990-01-01

    The automatic guidance of rotorcraft for obstacle avoidance in nap-of-the-earth flight is studied. A hierarchical breakdown of the guidance components is used to identify the functional requirements. These requirements and anticipated sensor capabilities lead to a preliminary guidance concept, which has been evaluated via computer simulations.

  13. Avoiding School Management Conflicts and Crisis through Formal Communication

    Science.gov (United States)

    Nwogbaga, David M. E.; Nwankwo, Oliver U.; Onwa, Doris O.

    2015-01-01

    This paper examined how conflicts and crisis can be avoided through formal communication. It was necessitated by the observation that most of the conflicts and crisis which tend to mar school management today are functions of the inconsistencies arising from "grapevines, rumours, and gossips" generated through informal communication…

  14. 28 CFR 552.23 - Confrontation avoidance procedures.

    Science.gov (United States)

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Confrontation avoidance procedures. 552.23 Section 552.23 Judicial Administration BUREAU OF PRISONS, DEPARTMENT OF JUSTICE INSTITUTIONAL MANAGEMENT CUSTODY Use of Force and Application of Restraints on Inmates § 552.23 Confrontation...

  15. Packet Drop Avoidance for High-speed network transmission protocol

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Guojun

    2004-05-01

    As network bandwidth continues to grow and longer paths are used to exchange large scientific data between storage systems and GRID computation, it has become increasingly obvious that there is a need to deploy a packet drop avoidance mechanism into network transmission protocols. Current end-to-end congestion avoidance mechanisms used in Transmission Control Protocol (TCP) have worked well on low bandwidth delay product networks, but with newer high-bandwidth delay networks they have shown to be inefficient and prone to unstable. This is largely due to increased network bandwidth coupled with changes in internet traffic patterns. These changes come from a variety of new network applications that are being developed to take advantage of the increased network bandwidth. This paper will examine the end-to-end congestion avoidance mechanism and perform a step-by-step analysis of its theory. In addition we will propose an alternative approach developed as part of a new network transmission protocol. Our alternative protocol uses a packet drop avoidance (PDA) mechanism built on top of the maximum burst size (MBS) theory combined with a real-time available bandwidth algorithm.

  16. 7 Ways to Avoid Serious Injury from School Sports

    Science.gov (United States)

    ... Site Map FAQs Contact Us Health Topics Drugs & Supplements Videos & Tools Español You Are Here: Home → Latest Health News → Article URL of this page: https://medlineplus.gov/news/fullstory_160474.html 7 Ways to Avoid Serious Injury From School Sports Know how to reduce the risk of getting ...

  17. Accident Avoidance Skill Training and Performance Testing. Final Report.

    Science.gov (United States)

    Hatterick, G. Richard; Barthurst, James R.

    A two-phased study was conducted to determine the feasibility of training drivers to acquire skills needed to avoid critical conflict motor vehicle accidents, and to develop the procedures and materials necessary for such training. Basic data were derived from indepth accident investigations and task analyses of driver behavior. Principal…

  18. Avoidance motivation and choking under pressure in soccer penalty shootouts

    NARCIS (Netherlands)

    Jordet, Geir; Hartman, Esther

    2008-01-01

    The purpose of this study was to examine the relationships between shot valence, avoidance behavior, and performance in soccer penalty shootouts. Video analyses were conducted with all penalty shootouts ever held ill the World Cup, the European Championships. and the UEFA Champions League (n = 36 sh

  19. Self-Avoiding Walks (SAWs), Entanglement and Biomolecules

    DEFF Research Database (Denmark)

    Hansen, Mikael Sonne

    2006-01-01

    The Self-Avoiding Walk (SAW) on a lattice are often used to study properties of polymers in good solvents such as entanglement, knotting (ring polymers), and statistical mechanical properties of polymers. Recently it has been used to explain the increased probability of phage DNA being knotted when...

  20. A Longitudinal Study of Experiential Avoidance in Emotional Disorders

    NARCIS (Netherlands)

    Spinhoven, Philip; Drost, Jolijn; de Rooij, Mark; van Hemert, Albert M.; Penninx, Brenda W.

    2014-01-01

    The aim of this study was to examine the degree in which measurements of trait experiential avoidance (EA) are affected by current emotional disorder and whether EA is a causal factor in the course of emotional disorders (anxiety and depressive disorders) and the development of comorbidity among emo

  1. A longitudinal study of experiential avoidance in emotional disorders

    NARCIS (Netherlands)

    Spinhoven, P.; Drost, J.; Rooij, M. de; Hemert, A.M. van; Penninx, B.W.J.H.

    2014-01-01

    The aim of this study was to examine the degree in which measurements of trait experiential avoidance (EA) are affected by current emotional disorder and whether EA is a causal factor in the course of emotional disorders (anxiety and depressive disorders) and the development of comorbidity among emo

  2. Avoiding asymmetry-induced bias in longitudinal image processing

    OpenAIRE

    Reuter, Martin; Fischl, Bruce

    2011-01-01

    Longitudinal image processing procedures frequently transfer or pool information across time within subject, with the dual goals of reducing the variability and increasing the accuracy of the derived measures. In this note, we discuss common difficulties in longitudinal image processing, focusing on the introduction of bias, and describe the approaches we have taken to avoid them in the FreeSurfer longitudinal processing stream.

  3. Avoid Vaccine Administration Errors with Seven Simple Steps

    Centers for Disease Control (CDC) Podcasts

    2012-02-16

    This podcast discusses seven simple ways to avoid vaccine administration errors in health care settings.  Created: 2/16/2012 by National Center for Immunization and Respiratory Diseases (NCIRD).   Date Released: 2/16/2012.

  4. Looking after your health. 3. Avoiding varicose veins.

    Science.gov (United States)

    Randall, Sara

    2015-02-01

    This article is to summarise key concepts for the health of the midwife with particular focus on standing for prolonged periods. One of the resultant factors relating to standing postures is the slow but avoidable progression of varicose veins. There is a strong genetic bias to these veins, which can be distressing, but here we will highlight awareness and current research.

  5. Food aquisition and predator avoidance in a Neotropical rodent

    NARCIS (Netherlands)

    Suselbeek, L.; Emsens, W.J.; Hirsch, B.T.; Kays, R.; Rowcliffe, J.M.; Zamore-Gutierrez, V.; Jansen, P.A.

    2014-01-01

    Foraging activity in animals reflects a compromise between acquiring food and avoiding predation. The Risk Allocation Hypothesis predicts that prey animals optimize this balance by concentrating their foraging activity at times of relatively low predation risk, as much as their energy status permits

  6. Fear-avoidance beliefs and pain avoidance in low back pain--translating research into clinical practice

    DEFF Research Database (Denmark)

    Rainville, James; Smeets, Rob J E M; Bendix, Tom;

    2011-01-01

    For patients with low back pain, fear-avoidance beliefs (FABs) represent cognitions and emotions that underpin concerns and fears about the potential for physical activities to produce pain and further harm to the spine. Excessive FABs result in heightened disability and are an obstacle for recov...... for recovery from acute, subacute, and chronic low back pain.......For patients with low back pain, fear-avoidance beliefs (FABs) represent cognitions and emotions that underpin concerns and fears about the potential for physical activities to produce pain and further harm to the spine. Excessive FABs result in heightened disability and are an obstacle...

  7. Recurrent, robust and scalable patterns underlie human approach and avoidance.

    Directory of Open Access Journals (Sweden)

    Byoung Woo Kim

    Full Text Available BACKGROUND: Approach and avoidance behavior provide a means for assessing the rewarding or aversive value of stimuli, and can be quantified by a keypress procedure whereby subjects work to increase (approach, decrease (avoid, or do nothing about time of exposure to a rewarding/aversive stimulus. To investigate whether approach/avoidance behavior might be governed by quantitative principles that meet engineering criteria for lawfulness and that encode known features of reward/aversion function, we evaluated whether keypress responses toward pictures with potential motivational value produced any regular patterns, such as a trade-off between approach and avoidance, or recurrent lawful patterns as observed with prospect theory. METHODOLOGY/PRINCIPAL FINDINGS: Three sets of experiments employed this task with beautiful face images, a standardized set of affective photographs, and pictures of food during controlled states of hunger and satiety. An iterative modeling approach to data identified multiple law-like patterns, based on variables grounded in the individual. These patterns were consistent across stimulus types, robust to noise, describable by a simple power law, and scalable between individuals and groups. Patterns included: (i a preference trade-off counterbalancing approach and avoidance, (ii a value function linking preference intensity to uncertainty about preference, and (iii a saturation function linking preference intensity to its standard deviation, thereby setting limits to both. CONCLUSIONS/SIGNIFICANCE: These law-like patterns were compatible with critical features of prospect theory, the matching law, and alliesthesia. Furthermore, they appeared consistent with both mean-variance and expected utility approaches to the assessment of risk. Ordering of responses across categories of stimuli demonstrated three properties thought to be relevant for preference-based choice, suggesting these patterns might be grouped together as a

  8. Sexual selection as a consequence of pathogen avoidance behaviors

    Energy Technology Data Exchange (ETDEWEB)

    Loehle, C. [Argonne National Lab., IL (United States); Logofet, D.O. [Russian Academy of Sciences, Moscow (Russian Federation). Laboratory of Mathematical Ecology

    1997-08-01

    The current theory that sexual selection results from female choice for good genes suffers from several problems. An alternative explanation is proposed. The pathogen avoidance hypothesis argues that the primary function of showy traits is to provide a reliable signal of current disease status so that sick individuals may be avoided during mating. Our studies shown that a significant risk of pathogen transmission occurs during mating and that showy traits are reliable indicators of current disease status. The origin of female choosiness is argued to lie in a general tendency to avoid sick individuals, even in the absence of showy traits. The showy traits are argued to originate as simple exaggerations of normal traits that are indicative of good health (bright feathers; vigorous movement; large size). Thus the origins of both showy traits and female choosiness are not problematic in this theory. A game theory analysis is employed to formalize the theory. Results of the game theory model support the theory. In particular, when the possession of male showy traits does not help reduce disease in the female, then showy traits are unlikely to occur. This case corresponds to the situation in large flocks or herds in which every animal is thoroughly exposed to all group pathogens on average. Such species do not exhibit showy traits. The good genes model does not make this prediction. The pathogen avoidance model can also lead to the evolution of showy traits even when selection is not effective against a given pathogen (e.g., when there is no heritable variation for resistance) but will lead to selection for resistance if such genes are present. Overall, the pathogen avoidance hypothesis provides a complete alternative to the good genes theory.

  9. A spatially explicit estimate of avoided forest loss.

    Science.gov (United States)

    Honey-Rosés, Jordi; Baylis, Kathy; Ramírez, M Isabel

    2011-10-01

    With the potential expansion of forest conservation programs spurred by climate-change agreements, there is a need to measure the extent to which such programs achieve their intended results. Conventional methods for evaluating conservation impact tend to be biased because they do not compare like areas or account for spatial relations. We assessed the effect of a conservation initiative that combined designation of protected areas with payments for environmental services to conserve over wintering habitat for the monarch butterfly (Danaus plexippus) in Mexico. To do so, we used a spatial-matching estimator that matches covariates among polygons and their neighbors. We measured avoided forest loss (avoided disturbance and deforestation) by comparing forest cover on protected and unprotected lands that were similar in terms of accessibility, governance, and forest type. Whereas conventional estimates of avoided forest loss suggest that conservation initiatives did not protect forest cover, we found evidence that the conservation measures are preserving forest cover. We found that the conservation measures protected between 200 ha and 710 ha (3-16%) of forest that is high-quality habitat for monarch butterflies, but had a smaller effect on total forest cover, preserving between 0 ha and 200 ha (0-2.5%) of forest with canopy cover >70%. We suggest that future estimates of avoided forest loss be analyzed spatially to account for how forest loss occurs across the landscape. Given the forthcoming demand from donors and carbon financiers for estimates of avoided forest loss, we anticipate our methods and results will contribute to future studies that estimate the outcome of conservation efforts. PMID:21902720

  10. Flight Deck Weather Avoidance Decision Support: Implementation and Evaluation

    Science.gov (United States)

    Wu, Shu-Chieh; Luna, Rocio; Johnson, Walter W.

    2013-01-01

    Weather related disruptions account for seventy percent of the delays in the National Airspace System (NAS). A key component in the weather plan of the Next Generation of Air Transportation System (NextGen) is to assimilate observed weather information and probabilistic forecasts into the decision process of flight crews and air traffic controllers. In this research we explore supporting flight crew weather decision making through the development of a flight deck predicted weather display system that utilizes weather predictions generated by ground-based radar. This system integrates and presents this weather information, together with in-flight trajectory modification tools, within a cockpit display of traffic information (CDTI) prototype. that the CDTI features 2D and perspective 3D visualization models of weather. The weather forecast products that we implemented were the Corridor Integrated Weather System (CIWS) and the Convective Weather Avoidance Model (CWAM), both developed by MIT Lincoln Lab. We evaluated the use of CIWS and CWAM for flight deck weather avoidance in two part-task experiments. Experiment 1 compared pilots' en route weather avoidance performance in four weather information conditions that differed in the type and amount of predicted forecast (CIWS current weather only, CIWS current and historical weather, CIWS current and forecast weather, CIWS current and forecast weather and CWAM predictions). Experiment 2 compared the use of perspective 3D and 21/2D presentations of weather for flight deck weather avoidance. Results showed that pilots could take advantage of longer range predicted weather forecasts in performing en route weather avoidance but more research will be needed to determine what combinations of information are optimal and how best to present them.

  11. Learning to Learn Cooperatively

    Science.gov (United States)

    Byrd, Anne Hammond

    2009-01-01

    Cooperative learning, put quite simply, is a type of instruction whereby students work together in small groups to achieve a common goal. Cooperative learning has become increasingly popular as a feature of Communicative Language Teaching (CLT) with benefits that include increased student interest due to the quick pace of cooperative tasks,…

  12. Comparison of male and female rats in avoidance of a moving object: more thigmotaxis, hypolocomotion and fear-like reactions in females.

    Science.gov (United States)

    Svoboda, J; Telenský, P; Blahna, K; Bureš, J; Stuchlík, A

    2012-01-01

    Although male rats generally outperform females in many spatial tasks, sometimes gender differences are not present. This preliminary study examined gender effects in the Enemy avoidance task, in which a rat on a stable circular arena avoids approaching a small mobile robot while collecting randomly dispersed small pellets. Whenever distance between robot and the rat dropped below 25 cm, animal was punished by a mild footshock. Female rats showed thigmotaxis, hypolocomotion and avoidance of robot in the habituation phase, when approaches were not punished. No statistically significant differences in avoidance learning under reinforcement training sessions were observed; but females still spent significantly more time at periphery of the arena and foraged less than males. We conclude that females were able to perform at the same level as males under reinforcement despite different behavioral strategy. The thigmotaxic behavior appears to function as innate escape strategy in female rats triggered by the stressing effect of the moving robot rather then the presence of shocks.

  13. A new learning algorithm with reference-following variables

    Institute of Scientific and Technical Information of China (English)

    Baiquan L(u); Yuan CAO

    2004-01-01

    A learning algorithm is presented for the learning of neural networks,in which the learning trajectory is convergence without any over-learning by changing of topological construction of the algorithm near any local minimum points of learning error.Because the topological construction is not convergent for some functions by usual BP method near some local minimum points,there is an over-learning phenomenon.To avoid the over-learning phenomenon, reference-following variables are used to change the topological construction of this algorithm.The theoretical analysis and the simulation results indicate that the proposed method is simple and useful.

  14. The sales learning curve.

    Science.gov (United States)

    Leslie, Mark; Holloway, Charles A

    2006-01-01

    When a company launches a new product into a new market, the temptation is to immediately ramp up sales force capacity to gain customers as quickly as possible. But hiring a full sales force too early just causes the firm to burn through cash and fail to meet revenue expectations. Before it can sell an innovative product efficiently, the entire organization needs to learn how customers will acquire and use it, a process the authors call the sales learning curve. The concept of a learning curve is well understood in manufacturing. Employees transfer knowledge and experience back and forth between the production line and purchasing, manufacturing, engineering, planning, and operations. The sales learning curve unfolds similarly through the give-and-take between the company--marketing, sales, product support, and product development--and its customers. As customers adopt the product, the firm modifies both the offering and the processes associated with making and selling it. Progress along the manufacturing curve is measured by tracking cost per unit: The more a firm learns about the manufacturing process, the more efficient it becomes, and the lower the unit cost goes. Progress along the sales learning curve is measured in an analogous way: The more a company learns about the sales process, the more efficient it becomes at selling, and the higher the sales yield. As the sales yield increases, the sales learning process unfolds in three distinct phases--initiation, transition, and execution. Each phase requires a different size--and kind--of sales force and represents a different stage in a company's production, marketing, and sales strategies. Adjusting those strategies as the firm progresses along the sales learning curve allows managers to plan resource allocation more accurately, set appropriate expectations, avoid disastrous cash shortfalls, and reduce both the time and money required to turn a profit.

  15. Learning to aid learning.

    Science.gov (United States)

    Richards, Jacqui

    2016-01-01

    The National Health Service (NHS) is one of the largest employers in the world and, with 1.3 million staff, the biggest employer in Europe. With over three hundred different careers on offer (NHS 2015), the acquisition of skills and qualifications, through academic and clinical training, is an integral part of day-to-day life in the health service. As such, mentoring has become a significant feature in the preparation of healthcare professionals, to support students and ensure learning needs and experiences are appropriate to competency. This article examines the mentor's role, in relation to a teaching innovation designed to address students' identified learning needs to meet the requirements of the multi-professional learning and assessment in practice course NM6156. The effectiveness of the aids to learning will be assessed through an online quiz, and its usefulness will be analysed with reference to educational theories of learning and development.

  16. Learning to aid learning.

    Science.gov (United States)

    Richards, Jacqui

    2016-01-01

    The National Health Service (NHS) is one of the largest employers in the world and, with 1.3 million staff, the biggest employer in Europe. With over three hundred different careers on offer (NHS 2015), the acquisition of skills and qualifications, through academic and clinical training, is an integral part of day-to-day life in the health service. As such, mentoring has become a significant feature in the preparation of healthcare professionals, to support students and ensure learning needs and experiences are appropriate to competency. This article examines the mentor's role, in relation to a teaching innovation designed to address students' identified learning needs to meet the requirements of the multi-professional learning and assessment in practice course NM6156. The effectiveness of the aids to learning will be assessed through an online quiz, and its usefulness will be analysed with reference to educational theories of learning and development. PMID:26975128

  17. Using Conceptual Lattices to Represent Fine Granular Learning Objects through SCORM Meta-Objects

    Science.gov (United States)

    Silva, Luciano; Mustaro, Pollyana N.; Stringhini, Denise; Silveira, Ismar F.

    2006-01-01

    Ideally, learning resources should be built over a shared pool of fine reusable granular learning objects. However, in order to avoid contextual lacks, dynamic creation of such resources would mostly rely on the conceptual relationships among learning objects inside a repository. These conceptual relationships, as well as the learning objects…

  18. Acoustic Image Models for Obstacle Avoidance with Forward-Looking Sonar

    Science.gov (United States)

    Masek, T.; Kölsch, M.

    Long-range forward-looking sonars (FLS) have recently been deployed in autonomous unmanned vehicles (AUV). We present models for various features in acoustic images, with the goal of using this sensor for altitude maintenance, obstacle detection and obstacle avoidance. First, we model the backscatter and FLS noise as pixel-based, spatially-varying intensity distributions. Experiments show that these models predict noise with an accuracy of over 98%. Next, the presence of acoustic noise from two other sources including a modem is reliably detected with a template-based filter and a threshold learned from training data. Lastly, the ocean floor location and orientation is estimated with a gradient-descent method using a site-independent template, yielding sufficiently accurate results in 95% of the frames. Temporal information is expected to further improve the performance.

  19. How cooperatively breeding birds identify relatives and avoid incest: New insights into dispersal and kin recognition.

    Science.gov (United States)

    Riehl, Christina; Stern, Caitlin A

    2015-12-01

    Cooperative breeding in birds typically occurs when offspring - usually males - delay dispersal from their natal group, remaining with the family to help rear younger kin. Sex-biased dispersal is thought to have evolved in order to reduce the risk of inbreeding, resulting in low relatedness between mates and the loss of indirect fitness benefits for the dispersing sex. In this review, we discuss several recent studies showing that dispersal patterns are more variable than previously thought, often leading to complex genetic structure within cooperative avian societies. These empirical findings accord with recent theoretical models suggesting that sex- biased dispersal is neither necessary, nor always sufficient, to prevent inbreeding. The ability to recognize relatives, primarily by learning individual or group-specific vocalizations, may play a more important role in incest avoidance than currently appreciated.

  20. How cooperatively breeding birds identify relatives and avoid incest: New insights into dispersal and kin recognition.

    Science.gov (United States)

    Riehl, Christina; Stern, Caitlin A

    2015-12-01

    Cooperative breeding in birds typically occurs when offspring - usually males - delay dispersal from their natal group, remaining with the family to help rear younger kin. Sex-biased dispersal is thought to have evolved in order to reduce the risk of inbreeding, resulting in low relatedness between mates and the loss of indirect fitness benefits for the dispersing sex. In this review, we discuss several recent studies showing that dispersal patterns are more variable than previously thought, often leading to complex genetic structure within cooperative avian societies. These empirical findings accord with recent theoretical models suggesting that sex- biased dispersal is neither necessary, nor always sufficient, to prevent inbreeding. The ability to recognize relatives, primarily by learning individual or group-specific vocalizations, may play a more important role in incest avoidance than currently appreciated. PMID:26577076

  1. Fear-avoidance beliefs and pain avoidance in low back pain--translating research into clinical practice

    DEFF Research Database (Denmark)

    Rainville, James; Smeets, Rob J E M; Bendix, Tom;

    2011-01-01

    For patients with low back pain, fear-avoidance beliefs (FABs) represent cognitions and emotions that underpin concerns and fears about the potential for physical activities to produce pain and further harm to the spine. Excessive FABs result in heightened disability and are an obstacle...

  2. 78 FR 28780 - Defense Federal Acquisition Regulation Supplement: Detection and Avoidance of Counterfeit...

    Science.gov (United States)

    2013-05-16

    ... Federal Acquisition Regulation Supplement: Detection and Avoidance of Counterfeit Electronic Parts (DFARS... detection and avoidance of counterfeit electronic parts. DATES: Comment Date: Comments on the proposed rule...-81, enacted December 31, 2011). Section 818 is entitled ``Detection and Avoidance of...

  3. Risk-Seeking Versus Risk-Avoiding Investments in Noisy Periodic Environments

    Science.gov (United States)

    Navarro-Barrientos, J. Emeterio; Walter, Frank E.; Schweitzer, Frank

    We study the performance of various agent strategies in an artificial investment scenario. Agents are equipped with a budget, x(t), and at each time step invest a particular fraction, q(t), of their budget. The return on investment (RoI), r(t), is characterized by a periodic function with different types and levels of noise. Risk-avoiding agents choose their fraction q(t) proportional to the expected positive RoI, while risk-seeking agents always choose a maximum value qmax if they predict the RoI to be positive ("everything on red"). In addition to these different strategies, agents have different capabilities to predict the future r(t), dependent on their internal complexity. Here, we compare "zero-intelligent" agents using technical analysis (such as moving least squares) with agents using reinforcement learning or genetic algorithms to predict r(t). The performance of agents is measured by their average budget growth after a certain number of time steps. We present results of extensive computer simulations, which show that, for our given artificial environment, (i) the risk-seeking strategy outperforms the risk-avoiding one, and (ii) the genetic algorithm was able to find this optimal strategy itself, and thus outperforms other prediction approaches considered.

  4. Amygdaloid and non-amygdaloid fear both influence avoidance of risky foraging in hungry rats.

    Science.gov (United States)

    Kim, Earnest; Kim, Eun Joo; Yeh, Regina; Shin, Minkyung; Bobman, Jake; Krasne, Franklin B; Kim, Jeansok J

    2014-09-01

    Considerable evidence seems to show that emotional and reflex reactions to feared situations are mediated by the amygdala. It might therefore seem plausible to expect that amygdala-coded fear should also influence decisions when animals make choices about instrumental actions. However, there is not good evidence of this. In particular, it appears, though the literature is conflicted, that once learning is complete, the amygdala may often not be involved in instrumental avoidance behaviours. It is therefore of interest that we have found in rats living for extended periods in a semi-naturalistic 'closed economy', where they were given random shocks in regions that had to be entered to obtain food, choices about feeding behaviour were in fact influenced by amygdala-coded fear, in spite of the null effect of amygdalar lesions on fear of dangerous location per se. We suggest that avoidance of highly motivated voluntary behaviour does depend in part on fear signals originating in the amygdala. Such signalling may be one role of well-known projections from amygdala to cortico-striate circuitry.

  5. Proposal on a sustainable strategy to avoid point source pollution of water with plant protection products.

    Science.gov (United States)

    Mestdagh, Inge; Bonicelli, Bernard; Laplana, Ramon; Roettele, Manfred

    2009-01-01

    Based on the results and lessons learned from the TOPPS project (Training the Operators to prevent Pollution from Point Sources), a proposal on a sustainable strategy to avoid point source pollution from Plant Protection Products (PPPs) was made. Within this TOPPS project (2005-2008), stakeholders were interviewed and research and analysis were done in 6 pilot catchment areas (BE, FR, DE, DK, IT, PL). Next, there was a repeated survey on operators' perception and opinion to measure changes resulting from TOPPS activities and good and bad practices were defined based on the Best Management Practices (risk analysis). Aim of the proposal is to suggest a strategy considering the differences between countries which can be implemented on Member State level in order to avoid PPP pollution of water through point sources. The methodology used for the up-scaLing proposal consists of the analysis of the current situation, a gap analysis, a consistency analysis and organisational structures for implementation. The up-scaling proposal focuses on the behaviour of the operators, on the equipment and infrastructure available with the operators. The proposal defines implementation structures to support correct behaviour through the development and updating of Best Management Practices (BMPs) and through the transfer and the implementation of these BMPs. Next, the proposal also defines requirements for the improvement of equipment and infrastructure based on the defined key factors related to point source pollution. It also contains cost estimates for technical and infrastructure upgrades to comply with BMPs.

  6. Prior exposure influences the behavioural avoidance by an intertidal gastropod, Bembicium auratum, of acidified waters

    Science.gov (United States)

    Amaral, Valter; Cabral, Henrique N.; Bishop, Melanie J.

    2014-01-01

    Phenotypic plasticity may be critical to the maintenance of viable populations under future environmental change. Here we examined the role of behavioural avoidance of sub-optimal conditions in enabling the intertidal gastropod, Bembicium auratum, to persist in mangrove forests affected by the low pH runoff from acid sulphate soils (ASS). Behaviourally, the gastropod may be able to avoid periods of particularly high acidity by using pneumatophores and/or mangrove trunks to vertically migrate above the water line or by retreating into its shell. We hypothesised that (1) B. auratum would display greater and more rapid vertical migration out of acidified than reference estuarine waters, and (2) responses would be more pronounced in gastropods collected from acidified than reference sites. Gastropods from acidified sites showed significantly higher activity in and more rapid migration out of acidified waters of pH 6.2-7.0, than reference waters or waters of pH impact of this stressor on their populations. The stronger response to acidification of gastropods from populations previously exposed to this stressor suggests that the response may be learned, inherited or induced over multiple exposures. Our study adds to growing evidence that estuarine organisms may exhibit considerable physiological and behaviour adaptive capacity to acidification. The potential for such adaptive capacity should be incorporated into studies seeking to forecast impacts to marine organisms of environmental change.

  7. Learned helplessness and social avoidance in the Wistar-Kyoto rat

    OpenAIRE

    Nam, Hyungwoo; Clinton, Sarah M; Jackson, Nateka L.; Kerman, Ilan A.

    2014-01-01

    The Wistar-Kyoto (WKY) rat is an established depression model characterized by elevated anxiety- and depression-like behavior across a variety of tests. Here we further characterized specific behavioral and functional domains relevant to depression that are altered in WKY rats. Moreover, since early-life experience potently shapes emotional behavior, we also determined whether aspects of WKYs' phenotype were modifiable by early-life factors using neonatal handling or maternal separation. We f...

  8. Learned helplessness and social avoidance in the Wistar-Kyoto rat

    OpenAIRE

    Hyungwoo eNam; Clinton, Sarah M; Jackson, Nateka L.; Kerman, Ilan A.

    2014-01-01

    The Wistar-Kyoto (WKY) rat is an established depression model characterized by elevated anxiety- and depression-like behavior across a variety of tests. Here we further characterized specific behavioral and functional domains relevant to depression that are altered in WKY rats. Moreover, since early-life experience potently shapes emotional behavior, we also determined whether aspects of WKYs’ phenotype were modifiable by early-life factors using neonatal handling or maternal separation. We f...

  9. Larger Error Signals in Major Depression are Associated with Better Avoidance Learning

    OpenAIRE

    Cavanagh, James F.; Bismark, Andrew J.; Frank, Michael J.; Allen, John J. B.

    2011-01-01

    The medial prefrontal cortex (mPFC) is particularly reactive to signals of error, punishment, and conflict in the service of behavioral adaptation and it is consistently implicated in the etiology of major depressive disorder (MDD). This association makes conceptual sense, given that MDD has been associated with hyper-reactivity in neural systems associated with punishment processing. Yet in practice, depression-related variance in measures of mPFC functioning often fails to relate to perform...

  10. Larger error signals in major depression are associated with better avoidance learning

    OpenAIRE

    James FCavanagh

    2011-01-01

    The medial prefrontal cortex (mPFC) is particularly reactive to signals of error, punishment, and conflict in the service of behavioral adaptation and it is consistently implicated in the etiology of Major Depressive Disorder (MDD). This association makes conceptual sense, given that MDD has been associated with hyper-reactivity in neural systems associated with punishment processing. Yet in practice, depression-related variance in measures of mPFC functioning often fails to relate to perfo...

  11. Brief postnatal exposure to phenobarbital impairs passive-avoidance learning and sensorimotor gating in rats

    OpenAIRE

    Gutherz, Samuel B.; Kulick, Catherine V.; Soper, Colin; Kondratyev, Alexei; Gale, Karen; Forcelli, Patrick A.

    2014-01-01

    Phenobarbital is the most commonly utilized drug for the treatment of neonatal seizures. However, mounting preclinical evidence suggests that even brief exposure to phenobarbital in the neonatal period can induce neuronal apoptosis, alterations in synaptic development, and long-lasting changes in behavioral functions. In the present report, we treated neonatal rat pups with phenobarbital and evaluated behavior in adulthood. Pups were treated initially with a loading dose (80mg/kg) on postnata...

  12. Young Students Learning Formal Algebraic Notation and Solving Linear Equations: Are Commonly Experienced Difficulties Avoidable?

    Science.gov (United States)

    Hewitt, Dave

    2012-01-01

    This study looks at a mixed ability group of 21 Year 5 primary students (aged 9-10 years old) who had previously never had formal instruction using letters to stand for unknowns or variables in a mathematics context; nor had they been introduced to formal algebraic notation. Three lessons were taught using the computer software "Grid Algebra"…

  13. Is It Cheating or Learning the Craft of Writing? Using Turnitin to Help Students Avoid Plagiarism

    Science.gov (United States)

    Graham-Matheson, Lynne; Starr, Simon

    2013-01-01

    Plagiarism is a growing problem for universities, many of which are turning to software detection for help in detecting and dealing with it. This paper explores issues around plagiarism and reports on a study of the use of Turnitin in a new university. The purpose of the study was to inform the senior management team about the plagiarism policy…

  14. Is it cheating or learning the craft of writing? Using Turnitin to help students avoid plagiarism

    Directory of Open Access Journals (Sweden)

    Lynne Graham-Matheson

    2013-04-01

    Full Text Available Plagiarism is a growing problem for universities, many of which are turning to software detection for help in detecting and dealing with it. This paper explores issues around plagiarism and reports on a study of the use of Turnitin in a new university. The purpose of the study was to inform the senior management team about the plagiarism policy and the use of Turnitin. The study found that staff and students largely understood the university's policy and Turnitin's place within it, and were very supportive of the use of Turnitin in originality checking. Students who had not used Turnitin were generally keen to do so. The recommendation to the senior management team, which was implemented, was that the use of Turnitin for originality checking should be made compulsory where possible – at the time of the study the use of Turnitin was at the discretion of programme directors. A further aim of the study was to contribute to the sector's body of knowledge. Prevention of plagiarism through education is a theme identified by Badge and Scott (2009 who conclude an area lacking in research is “investigation of the impact of these tools on staff teaching practices”. Although a number of recent studies have considered educational use of Turnitin they focus on individual programmes or subject areas rather than institutions as a whole and the relationship with policy.

  15. Measuring the Willingness to Pay to Avoid Guilt

    DEFF Research Database (Denmark)

    Bellemare, Charles; Sebald, Alexander Christopher; Strobel, Martin

    We estimate structural models of guilt aversion to measure the population level of willingness to pay (WTP) to avoid feeling guilt by letting down another player. We compare estimates of WTP under the assumption that higher-order beliefs are in equilibrium (i.e. consistent with the choice distrib...... is substantially overestimated (by a factor of two) when correlation between preferences and beliefs is not controlled for. Finally, we find no evidence that WTP is significantly related to the observable socio-economic characteristics of players....... experiment of proposal and response conducted with a large and representative sample of the Dutch population. Our range of estimates suggests that responders are willing to pay between 0.40 and 0.80 Euro to avoid letting down proposers by 1 Euro. Furthermore, we find that WTP estimated using stated beliefs...

  16. Measuring the willingness to pay to avoid guilt

    DEFF Research Database (Denmark)

    Bellemare, Charles; Sebald, Alexander Christopher; Strobel, Martin

    2011-01-01

    We estimate structural models of guilt aversion to measure the population level of willingness to pay (WTP) to avoid feeling guilt by letting down another player. We compare estimates of WTP under the assumption that higher-order beliefs are in equilibrium (i.e., consistent with the choice distri...... substantially overestimated (by a factor of two) when correlation between preferences and beliefs is not controlled for. Finally, we find no evidence that WTP is significantly related to the observable socio-economic characteristics of players....... experiment of proposal and response conducted with a large and representative sample of the Dutch population. Our range of estimates suggests that responders are willing to pay between ¤0.40 and ¤0.80 to avoid letting down proposers by ¤1. Furthermore, we find that WTP estimated using stated beliefs is...

  17. DAIDALUS: Detect and Avoid Alerting Logic for Unmanned Systems

    Science.gov (United States)

    Munoz, Cesar; Narkawicz, Anthony; Consiglio, Maria; Chamberlain, James; Hagen, George; Upchurch, Jason; Dutle, Aaron

    2015-01-01

    This paper presents DAIDALUS (Detect and Avoid Alerting Logic for Unmanned Systems), a reference implementation of a detect and avoid concept intended to support the integration of Unmanned Aircraft Systems into civil airspace. DAIDALUS consists of self-separation and alerting algorithms that provide situational awareness to UAS remote pilots. These algorithms have been formally specified in a mathematical notation and verified for correctness in an interactive theorem prover. The software implementation has been verified against the formal models and validated against multiple stressing cases jointly developed by the US Air Force Research Laboratory, MIT Lincoln Laboratory, and NASA. The DAIDALUS reference implementation is currently under consideration for inclusion in the appendices to the Minimum Operational Performance Standards for Unmanned Aircraft Systems presently being developed by RTCA Special Committee 228.

  18. The lengths birds will go to avoid incest.

    Science.gov (United States)

    Heinsohn, Robert

    2012-07-01

    Cooperatively breeding species, in which some individuals help others to rear their offspring, face a high risk of inbreeding because of close relatedness within social groups. Many species circumvent this problem via sex-biased dispersal, in which one sex is more likely to disperse (and to disperse further), while the other stays and helps. In the absence of sex-biased dispersal, more complex dispersal patterns can arise, based on kin recognition. However, this can also present challenges when dispersal distances are short, leading to clusters of relatives on neighbouring territories. In this issue, Nelson-Flower et al. (2012) break important new ground by unravelling adaptive incest-avoidance mechanisms in a cooperatively breeding bird without sex-biased dispersal. They provide an elegant demonstration of finely tuned dispersal distances together with cognitively based methods for knowing whom to avoid as mates.

  19. Airborne Collision Avoidance System as a Cyber-Physical System

    Directory of Open Access Journals (Sweden)

    Andrei C. NAE

    2015-12-01

    Full Text Available In this paper the key concepts of ITS - Intelligent Transport Systems, CPS - Cyber-Physical Systems and SM - Smart Mobility are defined and correlated with the need for ACAS – Airborne Collision Avoidance System, as the last resort safety net and indispensable ingredient in civil aviation. Smart Mobility is addressed from a Cyber Physical-Systems perspective, detailing some of the elements that this entails. Here we consider the Air Transportations System of the future as a Cyber-Physical System and analyze the implications of doing so from different perspectives. The objective is to introduce a 4D collision avoidance shield technology which forms a last resort safety net technology for the next generation air transport (2050 and beyond. The new system will represent a step change over the performance of current technology. As conclusions, the benefits of implementing Transport Cyber-Physical Systems are discussed, as well as what this would require for future deployment.

  20. Target Tracking and Obstacle Avoidance for Multi-agent Systems

    Institute of Scientific and Technical Information of China (English)

    Jing Yan; Xin-Ping Guan; Fu-Xiao Tan

    2010-01-01

    This paper considers the problems of target tracking and obstacle avoidance for multi-agent systems.To solve the problem that multiple agents cannot effectively track the target while avoiding obstacle in dynamic environment,a novel control algorithm based on potential function and behavior rules is proposed.Meanwhile,the interactions among agents are also considered.According to the state whether an agent is within the area of its neighbors' influence,two kinds of potential functions are presented.Meanwhile,the distributed control input of each agent is determined by relative velocities as well as relative positions among agents,target and obstacle.The maximum linear speed of the agents is also discussed.Finally,simulation studies are given to demonstrate the performance of the proposed algorithm.

  1. Kinetic description of collision avoidance in pedestrian crowds by sidestepping

    CERN Document Server

    Festa, Adriano; Wolfram, Marie-Therese

    2016-01-01

    In this paper we study a kinetic model for pedestrians, who are assumed to adapt their motion towards a desired direction while avoiding collisions with others by stepping aside. These minimal microscopic interaction rules lead to complex emergent macroscopic phenomena, such as velocity alignment in unidirectional flows and lane or stripe formation in bidirectional flows. We start by discussing collision avoidance mechanisms at the microscopic scale, then we study the corresponding Boltzmann-type kinetic description and its hydrodynamic mean-field approximation in the grazing collision limit. In the spatially homogeneous case we prove directional alignment under specific conditions on the sidestepping rules for both the collisional and the mean-field model. In the spatially inhomogeneous case we illustrate, by means of various numerical experiments, the rich dynamics that the proposed model is able to reproduce.

  2. Self-Avoiding Random Dynamics on Integer Complex Systems

    CERN Document Server

    Hamze, Firas; de Freitas, Nando

    2011-01-01

    This paper introduces a new specialized algorithm for equilibrium Monte Carlo sampling of binary-valued systems, which allows for large moves in the state space. This is achieved by constructing self-avoiding walks (SAWs) in the state space. As a consequence, many bits are flipped in a single MCMC step. We name the algorithm SARDONICS, an acronym for Self-Avoiding Random Dynamics on Integer Complex Systems. The algorithm has several free parameters, but we show that Bayesian optimization can be used to automatically tune them. SARDONICS performs remarkably well in a broad number of sampling tasks: toroidal ferromagnetic and frustrated Ising models, 3D Ising models, restricted Boltzmann machines and chimera graphs arising in the design of quantum computers.

  3. Structural characterization of ice polymorphs from self-avoiding walks

    CERN Document Server

    Herrero, Carlos P

    2014-01-01

    Topological properties of crystalline ice structures are studied by means of self-avoiding walks on their H-bond networks. The number of self-avoiding walks, C_n, for eight ice polymorphs has been obtained by direct enumeration up to walk length n = 27. This has allowed us to determine the `connective constant' or effective coordination number `mu' of these structures as the limit of the ratio C_n/C_{n-1} for large n. This structure-dependent parameter `mu' is related with other topological characteristics of ice polymorphs, such as the mean and minimum ring size, or the topological density of network sites. A correlation between the connective constant and the configurational entropy of hydrogen-disordered ice structures is discussed.

  4. Robotic Path Finding with Collision Avoidance Using Expert System

    Institute of Scientific and Technical Information of China (English)

    蔡自兴

    1989-01-01

    A rule-based expert system has been developed and used into a robotic planning system with collision-avoidance,The world model is represented as the knowledge data and stored in the knowledge base with rules.The expert system can find a collision-avoidance path.Otherwise.it shows the collision secton in which the moved object is blocked,Several examples for the different objects to pass through the different channels and to find a collision-free path have been tested.The simulating results of the palnner give out the planning sequence or blocked section(s).The output information is useful for making decision of the robot motion and modifyting the technological parameters of the world.

  5. Robotic Path Finding with Collision Avoidance Using Expert System

    Institute of Scientific and Technical Information of China (English)

    蔡自兴

    1989-01-01

    A rule-based expert system has been developed and used into a robotic planning system with collision-avoidance, The world model is represented as the knowledge data and stored in the knowledge base with rules. The expert system can find a collision-avoidance path . Otherwise, it shows the collision secton in which the moved object is blocked . Several examples for the different objects to pass throngli the different channels and to find a collision-free path have been testnd. The simulating resuks of the planner give out the planning sequence or blocked section(s) . The output information is useful for making decision of the robot motion and modifying the technological parameters of the world .

  6. [Big data, Roemer's law and avoidable hospital admissions].

    Science.gov (United States)

    van der Horst, H E

    2016-01-01

    From an analysis of data from 23 European countries to determine the impact of primary care on avoidable hospital admissions for uncontrolled diabetes it appeared that, contrary to expectation, countries with strong primary care did not have a lower rate of avoidable hospital admission. It is clear that Roemer's law, 'a bed built is a bed filled,' still applies. However, the validity of this sort of analysis can be questioned, as these data are highly aggregated, and registration quality differs between countries. It is also questionable if these datasets can be considered as 'big data' as there are relatively small numbers per country. Big data analyses are useful for discerning patterns and formulating hypotheses, but not for proving causality. An unwanted side effect of this kind of analysis might be that policymakers use these not so valid results to underpin their policy to their advantage. PMID:27484429

  7. Real-Time Fuzzy Obstacle Avoidance Using Directional Visual Perception

    Institute of Scientific and Technical Information of China (English)

    Huang Guoquan(黄国权); Rad A. B.; Wong Y. K.

    2004-01-01

    This paper presents a novel vision-based obstacle avoidance approach for the Autonomous Mobile Robot (AMR) with a Pan- Tilt-Zoom (PTZ) camera as its only sensing modality. The approach combines the morphological closing operation based on Sobel Edge Detection Operation and the (μ-kσ) thresholding technique to detect obstacles to soften the various lighting and ground floor effects. Both the morphology method and thresholding technique are computationally simple. The processing speed of the algorithm is fast enough to avoid some active obstacles. In addition, this approach takes into account the history obstacle effects on the current state. Fuzzy logic is used to control the behaviors of AMR as it navigates in the environment. All behaviors run concurrently and generate motor response solely based on vision perception. A priority based on subsumption coordinator selects the most appropriate response to direct the AMR away from obstacles. Validation of the proposed approach is done on a Pioneer 1 mobile robot.

  8. Avoidance within a changing assessment paradigm for Mediterranean Hake stocks

    Directory of Open Access Journals (Sweden)

    S. RAGONESE

    2012-12-01

    Full Text Available The Mediterranean hake Merluccius merluccius L., 1758, is the emblem of the so-called Mediterranean demersal fisheries paradox, showing a persistent, although stable, status of growth overexploitation and an impressive gap between current and any biological reference point. Almost full avoidance capability of large size females to bottom trawls, higher overall growth rates than previously believed and higher natural mortality in juveniles than adult, were considered among the most plausible explanation factors of such persistence. In the present note, arguments are illustrated to raise some concern about avoidance and highlight the important role of the other factors in improving assessments and launching a short term recovery plan for Mediterranean Hake stocks which is more acceptable to fishermen.

  9. Departures from optimality when pursuing multiple approach or avoidance goals.

    Science.gov (United States)

    Ballard, Timothy; Yeo, Gillian; Neal, Andrew; Farrell, Simon

    2016-07-01

    This article examines how people depart from optimality during multiple-goal pursuit. The authors operationalized optimality using dynamic programming, which is a mathematical model used to calculate expected value in multistage decisions. Drawing on prospect theory, they predicted that people are risk-averse when pursuing approach goals and are therefore more likely to prioritize the goal in the best position than the dynamic programming model suggests is optimal. The authors predicted that people are risk-seeking when pursuing avoidance goals and are therefore more likely to prioritize the goal in the worst position than is optimal. These predictions were supported by results from an experimental paradigm in which participants made a series of prioritization decisions while pursuing either 2 approach or 2 avoidance goals. This research demonstrates the usefulness of using decision-making theories and normative models to understand multiple-goal pursuit. (PsycINFO Database Record PMID:26963081

  10. Phase-space picture of resonance creation and avoided crossings

    CERN Document Server

    Timberlake, T

    2000-01-01

    Complex coordinate scaling (CCS) is used to calculate resonance eigenvalues and eigenstates for a system consisting of an inverted Gaussian potential and a monochromatic driving field. Floquet eigenvalues and Husimi distributions of resonance eigenfunctions are calculated using two different versions of CCS. The number of resonance states in this system increases as the strength of the driving field is increased, indicating that this system might have increased stability against ionization when the field strength is very high. We find that the newly created resonance states are scarred on unstable periodic orbits of the classical motion. The behavior of these periodic orbits as the field strength is increased may explain why there are more resonance states at high field strengths than at low field strengths. Close examination of an avoided crossing between resonance states shows that this type of avoided crossing does not delocalize the resonance states, although it may lead to interesting effects at certain ...

  11. Getting Obstacle Avoidance Trajectory of Mobile Beacon for Localization

    Directory of Open Access Journals (Sweden)

    Huan-Qing CUI

    2010-11-01

    Full Text Available Localization is one of the most important technologies in wireless sensor network, and mobile beacon assisted localization is a promising localization method. The mobile beacon trajectory planning is a basic and important problem in these methods. There are many obstacles in the real world, which obstruct the moving of mobile beacon. This paper focuses on the obstacle avoidance trajectory planning scheme. After partitioning the deployment area with fixed cell decomposition, the beacon trajectory are divided into global and local trajectory. The approximate shortest global trajectory is obtained by depth-first search, greedy strategy method and ant colony algorithm, while local trajectory is any existing trajectories. Simulation results show that this method can avoid obstacles in the network deployment area, and the smaller cell size leads to longer beacon trajectory and more localizable sensor nodes.

  12. Dopamine Regulates Approach-Avoidance in Human Sensation-Seeking

    OpenAIRE

    Norbury, A.; Kurth-Nelson, Z.; Winston, J. S.; Roiser, J.P.; M. Husain

    2015-01-01

    Background: Sensation-seeking is a trait that constitutes an important vulnerability factor for a variety of psychopathologies with high social cost. However, little is understood either about the mechanisms underlying motivation for intense sensory experiences or their neuropharmacological modulation in humans. Methods: Here, we first evaluate a novel paradigm to investigate sensation-seeking in humans. This test probes the extent to which participants choose either to avoid or self-administ...

  13. Factors associated with healthcare avoidance among transgender women in Argentina

    OpenAIRE

    Socías, María Eugenia; Marshall, Brandon DL; Arístegui, Inés; Romero, Marcela; Cahn, Pedro; Kerr, Thomas; Sued, Omar

    2014-01-01

    Introduction Transgender (TG) women in many settings continue to contend with barriers to healthcare, including experiences of stigma and discrimination. Argentina has a universal health care system and laws designed to promote healthcare access among TG women. However, little is known about barriers to healthcare access among TG women in this setting. The aim of this study was to explore individual, social-structural and environmental factors associated with healthcare avoidance among TG wom...

  14. Real-time collision avoidance in space: the GETEX experiment

    Science.gov (United States)

    Freund, Eckhard; Rossmann, Juergen; Schluse, Michael

    2000-10-01

    Intelligent autonomous robotic systems require efficient safety components to assure system reliability during the entire operation. Especially if commanded over long distances, the robotic system must be able to guarantee the planning of safe and collision free movements independently. Therefore the IRF developed a new collision avoidance methodology satisfying the needs of autonomous safety systems considering the dynamics of the robots to protect. To do this, the collision avoidance system cyclically calculates the actual collision danger of the robots with respect to all static and dynamic obstacles in the environment. If a robot gets in collision danger the methodology immediately starts an evasive action to avoid the collision and guides the robot around the obstacle to its target position. This evasive action is calculated in real-time in a mathematically exact way by solving a quadratic convex optimization problem. The secondary conditions of this optimization problem include the potential collision danger of the robots kinematic chain including all temporarily attached grippers and objects and the dynamic constraints of the robots. The result of the optimization procedure are joint accelerations to apply to prevent the robot from colliding and to guide it to its target position. This methodology has been tested very successfully during the Japanese/German space robot project GETEX in April 1999. During the mission, the collision avoidance system successfully protected the free flying Japanese robot ERA on board the satellite ETS-VII at all times. The experiments showed, that the developed system is fully capable of ensuring the safety of such autonomous robotic systems by actively preventing collisions and generating evasive actions in cases of collision danger.

  15. Platform Siphoning: Ad-Avoidance and Media Content

    OpenAIRE

    Simon P. Anderson; Joshua S. Gans

    2011-01-01

    Content providers rely on advertisers to pay for content. TiVo, remote controls, and pop-up ad blockers are examples of ad-avoidance technologies that allow consumers to view content without ads, and thereby siphon off the content without paying the "price." We examine the content provider's reaction to such technologies, demonstrating that their adoption increases advertising clutter (leading to a potential downward spiral), may reduce total welfare and content quality, and can lead to more ...

  16. Procrastination and counterfactual thinking: avoiding what might have been.

    OpenAIRE

    Sirois, F.M.

    2004-01-01

    The possible negative consequences of counterfactuals were explored in the current study by examining the relationship between counterfactual direction and trait procrastination, a self-defeating behavioural style. Eighty participants generated counterfactuals in response to two experimental anxiety inductions. Trait procrastination was overall related to avoiding thoughts about how things could have been better (making more downward and relatively fewer upward counterfactuals) in response to...

  17. Recognition of Threshold Dose Model: Avoiding Continued Excessive Regulation

    International Nuclear Information System (INIS)

    The purpose of this work is to examine the relationships between radiation dose-response models and associated regulations. It is concluded that recognition of the validity of a threshold model can be done on the basis of presently known data and that changes in regulations should be started at this time to avoid further unnecessary losses due to continued excessive regulation. As results from new research come in, refinement of interim values proposed in revised regulations can be incorporated

  18. Avoiding Dirty Air (A Cup of Health with CDC)

    Centers for Disease Control (CDC) Podcasts

    2014-05-01

    As summertime approaches and warmer weather moves in, air pollution will become an increasing problem across the U.S. People with asthma are especially impacted by deteriorating air quality. In this podcast, Dr. Suzanne Beavers discusses ways to avoid the negative impacts of air pollution.  Created: 5/1/2014 by MMWR.   Date Released: 5/1/2014.

  19. Avoidance of petroleum hydrocarbons by the cod (Gadus morhua)

    OpenAIRE

    Bøhle, Bjørn

    1986-01-01

    The experimental fish were held in two different aquaria, one with three and one with two compartments. Water containing "water soluble fraction" of Fuel Oil No. 2 was introduced in one of the compartments. By means of light- and sound-based detectors, the amount of time spent by the fish in the various compartments was recorded. Although the results were somewhat contradictory, it seems that the fish avoided water containing more than 100 µg/l of the petroleum hydrocarbons.

  20. Multiple System-Decomposition Method for Avoiding Quantum Decoherence

    Institute of Scientific and Technical Information of China (English)

    J.Jekni(c)-Dugi(c); M.Dugi(c)

    2008-01-01

    Decomposition of a composite system C into different subsystems,A+B or D+ε,may help in avoiding decoherence.For example,the environment-induced decoherence for an A+B system need not destroy entanglement present in the D+ε system(A+B=C=D+ε).This new approach opens some questions also in the foundations of the quantum computation theory that might eventually lead to a new model of quantum computation.