WorldWideScience

Sample records for avoidance learning

  1. Learning to Avoid Risky Actions

    OpenAIRE

    Malfaz, María; Miguel A. Salichs

    2011-01-01

    When a reinforcement learning agent executes actions that can cause frequent damage to itself, it can learn, by using Q-learning, that these actions must not be executed again. However, there are other actions that do not cause damage frequently but only once in a while, for example, risky actions such as parachuting. These actions may imply punishment to the agent and, depending on its personality, it would be better to avoid them. Nevertheless, using the standard Q-learning algorithm, the a...

  2. Learning processes underlying avoidance of negative outcomes.

    Science.gov (United States)

    Andreatta, Marta; Michelmann, Sebastian; Pauli, Paul; Hewig, Johannes

    2017-04-01

    Successful avoidance of a threatening event may negatively reinforce the behavior due to activation of brain structures involved in reward processing. Here, we further investigated the learning-related properties of avoidance using feedback-related negativity (FRN). The FRN is modulated by violations of an intended outcome (prediction error, PE), that is, the bigger the difference between intended and actual outcome, the larger the FRN amplitude is. Twenty-eight participants underwent an operant conditioning paradigm, in which a behavior (button press) allowed them to avoid a painful electric shock. During two learning blocks, participants could avoid an electric shock in 80% of the trials by pressing one button (avoidance button), or by not pressing another button (punishment button). After learning, participants underwent two test blocks, which were identical to the learning ones except that no shocks were delivered. Participants pressed the avoidance button more often than the punishment button. Importantly, response frequency increased throughout the learning blocks but it did not decrease during the test blocks, indicating impaired extinction and/or habit formation. In line with a PE account, FRN amplitude to negative feedback after correct responses (i.e., unexpected punishment) was significantly larger than to positive feedback (i.e., expected omission of punishment), and it increased throughout the blocks. Highly anxious individuals showed equal FRN amplitudes to negative and positive feedback, suggesting impaired discrimination. These results confirm the role of negative reinforcement in motivating behavior and learning, and reveal important differences between high and low anxious individuals in the processing of prediction errors.

  3. 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.

  4. 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

  5. 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…

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

    Science.gov (United States)

    Kim, Hackjin; Shimojo, Shinsuke; O'Doherty, John P

    2006-07-01

    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.

  7. Linking Individual Learning Styles to Approach-Avoidance Motivational Traits and Computational Aspects of Reinforcement Learning

    OpenAIRE

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

    2016-01-01

    Learning how to gain rewards (approach learning) and avoid punishments (avoidance learning) is fundamental for everyday life. While individual differences in approach and avoidance learning styles have been related to genetics and aging, the contribution of personality factors, such as traits, remains undetermined. Moreover, little is known about the computational mechanisms mediating differences in learning styles. Here, we used a probabilistic selection task with positive and negative feedb...

  8. A Proposal of Predictive Reinforcement Learning Realizing Moving Obstacle Avoidance

    Science.gov (United States)

    Takeda, Masato; Nagao, Tomoharu

    In recent years, researches on autonomous robots in real life have developed. Especially, moving obstacle avoidance is one of the most important tasks for robots. Reinforcement learning is a typical method of action acquisitions of autonomous mobile robots for obstacle avoidance. However, it has been indicated that reinforcement learning has various problems in unknown environment. In order to solve these problems, we propose predictive reinforcement learning for moving obstacle avoidance. In predictive reinforcement learning, our rules are not defined as a pair of actions and states like conventional reinforcement learning. The rules are defined as the transition of the states by robot action between steps. We think that proposed rules enable robots to adapt to unknown environment because these rules are independent from any environment where moving obstacles exist. The robots implemented these rules predict the next state. After this prediction, the robots reinforce its rules by comparing observed states with predicted ones and foresee collisions on obstacles. Then the robots select safer actions. In this paper, we verify the efficiency of our method in several simulations. First, the robot is trained in learning environment where moving obstacles exist. After that, we experiment to verify the ability of adaptation to unknown environments. As a result, the robot acquires moving obstacle avoidance actions.

  9. Linking Individual Learning Styles to Approach-Avoidance Motivational Traits and Computational Aspects of Reinforcement Learning.

    Science.gov (United States)

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

    2016-01-01

    Learning how to gain rewards (approach learning) and avoid punishments (avoidance learning) is fundamental for everyday life. While individual differences in approach and avoidance learning styles have been related to genetics and aging, the contribution of personality factors, such as traits, remains undetermined. Moreover, little is known about the computational mechanisms mediating differences in learning styles. Here, we used a probabilistic selection task with positive and negative feedbacks, in combination with computational modelling, to show that individuals displaying better approach (vs. avoidance) learning scored higher on measures of approach (vs. avoidance) trait motivation, but, paradoxically, also displayed reduced learning speed following positive (vs. negative) outcomes. These data suggest that learning different types of information depend on associated reward values and internal motivational drives, possibly determined by personality traits.

  10. Linking Individual Learning Styles to Approach-Avoidance Motivational Traits and Computational Aspects of Reinforcement Learning

    Science.gov (United States)

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

    2016-01-01

    Learning how to gain rewards (approach learning) and avoid punishments (avoidance learning) is fundamental for everyday life. While individual differences in approach and avoidance learning styles have been related to genetics and aging, the contribution of personality factors, such as traits, remains undetermined. Moreover, little is known about the computational mechanisms mediating differences in learning styles. Here, we used a probabilistic selection task with positive and negative feedbacks, in combination with computational modelling, to show that individuals displaying better approach (vs. avoidance) learning scored higher on measures of approach (vs. avoidance) trait motivation, but, paradoxically, also displayed reduced learning speed following positive (vs. negative) outcomes. These data suggest that learning different types of information depend on associated reward values and internal motivational drives, possibly determined by personality traits. PMID:27851807

  11. 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.

  12. 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.

  13. 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.

  14. Estrogenic involvement in social learning, social recognition and pathogen avoidance.

    Science.gov (United States)

    Choleris, Elena; Clipperton-Allen, Amy E; Phan, Anna; Valsecchi, Paola; Kavaliers, Martin

    2012-04-01

    Sociality comes with specific cognitive skills that allow the proper processing of information about others (social recognition), as well as of information originating from others (social learning). Because sociality and social interactions can also facilitate the spread of infection among individuals the ability to recognize and avoid pathogen threat is also essential. We review here various studies primarily from the rodent literature supporting estrogenic involvement in the regulation of social recognition, social learning (socially acquired food preferences and mate choice copying) and the recognition and avoidance of infected and potentially infected individuals. We consider both genomic and rapid estrogenic effects involving estrogen receptors α and β, and G-protein coupled estrogen receptor 1, along with their interactions with neuropeptide systems in the processing of social stimuli and the regulation and expression of these various socially relevant behaviors.

  15. 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.

  16. Place avoidance learning and memory in a jumping spider.

    Science.gov (United States)

    Peckmezian, Tina; Taylor, Phillip W

    2017-03-01

    Using a conditioned passive place avoidance paradigm, we investigated the relative importance of three experimental parameters on learning and memory in a salticid, Servaea incana. Spiders encountered an aversive electric shock stimulus paired with one side of a two-sided arena. Our three parameters were the ecological relevance of the visual stimulus, the time interval between trials and the time interval before test. We paired electric shock with either a black or white visual stimulus, as prior studies in our laboratory have demonstrated that S. incana prefer dark 'safe' regions to light ones. We additionally evaluated the influence of two temporal features (time interval between trials and time interval before test) on learning and memory. Spiders exposed to the shock stimulus learned to associate shock with the visual background cue, but the extent to which they did so was dependent on which visual stimulus was present and the time interval between trials. Spiders trained with a long interval between trials (24 h) maintained performance throughout training, whereas spiders trained with a short interval (10 min) maintained performance only when the safe side was black. When the safe side was white, performance worsened steadily over time. There was no difference between spiders tested after a short (10 min) or long (24 h) interval before test. These results suggest that the ecological relevance of the stimuli used and the duration of the interval between trials can influence learning and memory in jumping spiders.

  17. Sex-specific positive and negative consequences of avoidance training during childhood on adult active avoidance learning in mice

    Directory of Open Access Journals (Sweden)

    Almuth eSpröwitz

    2013-10-01

    Full Text Available In humans and animals cognitive training during childhood plays an important role in shaping neural circuits and thereby determines learning capacity later in life. Using a negative feedback learning paradigm, the two-way active avoidance (TWA learning, we aimed to investigate in mice (i the age-dependency of TWA learning, (ii the consequences of pretraining in childhood on adult learning capacity and (iii the impact of sex on the learning paradigm in mice. Taken together, we show here for the first time that the beneficial or detrimental outcome of pretraining in childhood depends on the age during which TWA training is encountered, indicating that different, age-dependent long-term memory traces might be formed, which are recruited during adult TWA training and thereby either facilitate or impair adult TWA learning. While pretraining during infancy results in learning impairment in adulthood, pretraining in late adolescence improved avoidance learning.The experiments revealed a clear sex difference in the group of late-adolescent mice: female mice showed better avoidance learning during late adolescence compared to males, and the beneficial impact of late-adolescent pretraining on adult learning was more pronounced in females compared to males.

  18. 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…

  19. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  1. 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

  2. Information Seeking and Avoidance Behavior in School Library Distance Learning

    Science.gov (United States)

    Du, Yunfei

    2010-01-01

    Library science students in school librarianship were surveyed to determine their information seeking and avoidance behaviors in Web-based online environments. Two coping styles were identified among students. Barriers to student online collaboration, such as individual preferences, concerns on efficiency, and lack of mutual trust, were observed.…

  3. 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 to navigate to correct platforms while avoiding incorrect platforms. To manipulate motivational states participants were either rewarded for navigating to correct locations (approach) or punished for navigating to incorrect platforms (avoidance). Participants' skin conductance levels (SCLs) were recorded during navigation to investigate the role of physiological arousal in motivated learning. Behavioral results revealed that, overall, approach motivation enhanced and avoidance motivation impaired memory performance compared to nonmotivated spatial learning. This advantage was evident across several performance indices, including accuracy, learning rate, path length, and proximity to platform locations during probe trials. SCL analysis revealed three key findings. First, within subjects, arousal interacted with approach motivation, such that high arousal on a given trial was associated with performance deficits. In addition, across subjects, high arousal negated or reversed the benefits of approach motivation. Finally, low-performing, highly aroused participants showed SCL responses similar to those of avoidance-motivation participants, suggesting that for these individuals, opportunities for reward may evoke states of learning similar to those typically evoked by threats of punishment. These results provide a novel characterization of how approach and avoidance motivation influence declarative memory and indicate a critical and selective role for arousal in determining how reinforcement influences goal-oriented learning.

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

    Directory of Open Access Journals (Sweden)

    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.

  5. 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.

  6. Lesions of the lateral habenula facilitate active avoidance learning and threat extinction.

    Science.gov (United States)

    Song, Mihee; Jo, Yong Sang; Lee, Yeon-Kyung; Choi, June-Seek

    2017-02-01

    The lateral habenula (LHb) is an epithalamic brain structure that provides strong projections to midbrain monoaminergic systems that are involved in motivation, emotion, and reinforcement learning. LHb neurons are known to convey information about aversive outcomes and negative prediction errors, suggesting a role in learning from aversive events. To test this idea, we examined the effects of electrolytic lesions of the LHb on signaled two-way active avoidance learning in which rats were trained to avoid an unconditioned stimulus (US) by taking a proactive shuttling response to an auditory conditioned stimulus (CS). The lesioned animals learned the avoidance response significantly faster than the control groups. In a separate experiment, we also investigated whether the LHb contributes to Pavlovian threat (fear) conditioning and extinction. Following paired presentations of the CS and the US, LHb-lesioned animals showed normal acquisition of conditioned response (CR) measured with freezing. However, extinction of the CR in the subsequent CS-only session was significantly faster. The enhanced performance in avoidance learning and in threat extinction jointly suggests that the LHb normally plays an inhibitory role in learning driven by absence of aversive outcomes.

  7. Learned Avoidance in the Male Syrian Hamster: Investigating the Outcome of a Glucocorticoid Antagonist on Reconsolidation

    Directory of Open Access Journals (Sweden)

    Erik Haugsnes

    2015-02-01

    Full Text Available In this experiment, we used our Conflict Alleyway Apparatus and a glucocorticoid antagonist, mifepristone, to investigate the role of glucocorticoids in the reconsolidation of learned avoidance in defeated male Syrian hamsters. Subjects were tested for memory deficits 48 hours and 96 hours after the drug/vehicle was administered. It were hypothesized that mifepristone administration would produce memory deficits when the defeat memory had been reactivated, and that this deficit would be present 48 hours and 96 hours after the administration. Prolonged deficits that are dependent upon memory reactivation would suggest that glucocorticoids play a role in reconsolidation of learned avoidance. Our results indicated a strong evidence for learned avoidance after defeat; however, we did not find any significant drug effect.

  8. Learning by stimulation avoidance: A principle to control spiking neural networks dynamics.

    Science.gov (United States)

    Sinapayen, Lana; Masumori, Atsushi; Ikegami, Takashi

    2017-01-01

    Learning based on networks of real neurons, and learning based on biologically inspired models of neural networks, have yet to find general learning rules leading to widespread applications. In this paper, we argue for the existence of a principle allowing to steer the dynamics of a biologically inspired neural network. Using carefully timed external stimulation, the network can be driven towards a desired dynamical state. We term this principle "Learning by Stimulation Avoidance" (LSA). We demonstrate through simulation that the minimal sufficient conditions leading to LSA in artificial networks are also sufficient to reproduce learning results similar to those obtained in biological neurons by Shahaf and Marom, and in addition explains synaptic pruning. We examined the underlying mechanism by simulating a small network of 3 neurons, then scaled it up to a hundred neurons. We show that LSA has a higher explanatory power than existing hypotheses about the response of biological neural networks to external simulation, and can be used as a learning rule for an embodied application: learning of wall avoidance by a simulated robot. In other works, reinforcement learning with spiking networks can be obtained through global reward signals akin simulating the dopamine system; we believe that this is the first project demonstrating sensory-motor learning with random spiking networks through Hebbian learning relying on environmental conditions without a separate reward system.

  9. Context preexposure influences the effectiveness of feedback stimuli in avoidance learning.

    Science.gov (United States)

    Callen, Edward J

    2004-04-30

    According to the effective reinforcement theory of avoidance learning, there is a positive relationship between the level of context fear and the effectiveness of feedback stimuli. The present research used different preexposure treatments to manipulate context fear and to evaluate the effects of feedback stimuli in two-way avoidance learning. Rat subjects received nonreinforced preexposure either to the nonvisual context cues (avoidance apparatus with the houselights extinguished), to the visual context cues (avoidance apparatus with the houselights on but with a Plexiglas floor covering the grids), or to a neutral box. During subsequent avoidance training conditioned stimulus termination was delayed for 5s after an instrumental response and either a flashing light or darkness was presented as a feedback stimulus. Without preexposure, darkness produced better avoidance performance than did the flashing light. Preexposure to the visual context cues decreased the effectiveness of darkness as a feedback stimulus. However, preexposure to either the visual or to the nonvisual context cues facilitated avoidance performance when a flashing light was used as a feedback stimulus. The results suggest that the effects of a feedback stimulus may be dependent upon the amount and source of context fear.

  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. 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.

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

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    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.

  14. 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.

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

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    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.

  16. Endomorphins 1 and 2, endogenous mu-opioid receptor agonists, impair passive avoidance learning in mice.

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    Ukai, M; Watanabe, Y; Kameyama, T

    2001-06-08

    The effects of intracerebroventricular administration of endomorphin-1 and endomorphin-2, endogenous mu-opioid receptor agonists, on passive avoidance learning associated with long-term memory were investigated in mice. Endomorphin-1 (10 and 17.5 microg) and endomorphin-2 (17.5 microg) produced a significant decrease in step-down latency in a passive avoidance learning task. beta-Funaltrexamine (5 microg) almost completely reversed the endomorphin-1 (17.5 microg)- and endomorphin-2 (17.5 microg)-induced shortening of step-down latency, although neither naltrindole (4 ng) nor nor-binaltorphimine (4 microg) produced any significant effects on the effects of endomorphins 1 and 2. These results suggest that endomorphins 1 and 2 impair long-term memory through the mediation of mu-opioid receptors in the brain.

  17. 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

  18. Using signals associated with safety in avoidance learning: computational model of sex differences

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    Milen L. Radell

    2015-07-01

    Full Text Available Avoidance behavior involves learning responses that prevent upcoming aversive events; these responses typically extinguish when the aversive events stop materializing. Stimuli that signal safety from aversive events can paradoxically inhibit extinction of avoidance behavior. In animals, males and females process safety signals differently. These differences help explain why women are more likely to be diagnosed with an anxiety disorder and exhibit differences in symptom presentation and course compared to men. In the current study, we extend an existing model of strain differences in avoidance behavior to simulate sex differences in rats. The model successfully replicates data showing that the omission of a signal associated with a period of safety can facilitate extinction in females, but not males, and makes novel predictions that this effect should depend on the duration of the period, the duration of the signal itself, and its occurrence within that period. Non-reinforced responses during the safe period were also found to be important in the expression of these patterns. The model also allowed us to explore underlying mechanisms for the observed sex effects, such as whether safety signals serve as occasion setters for aversive events, to determine why removing them can facilitate extinction of avoidance. The simulation results argue against this account, and instead suggest the signal may serve as a conditioned reinforcer of avoidance behavior.

  19. 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.

  20. Effects of prenatal exposure to combined stress on memory retention of passive avoidance learning in rats

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    Z. Homauni Afshari

    2015-10-01

    Full Text Available Background: Many studies have shown that prenatal stress affects development of fetal brain. Objective: The aim of this study was to evaluate the effect of prenatal exposure to combined stress on memory retention of passive avoidance learning in rats. Methods: This experimental study was performed on 16 male and 16 female Wistar rats in 2014. The rats were divided into four groups: male and female control groups, with natural pregnancy and two male and female treatment groups with exposure to combined stress (electromagnetic field, immobility and social stress in the second and third weeks of embryonic development. The learning was evaluated using shuttle box setup. Data were analyzed using ANOVA and Tukey test. Findings: The prenatal combined stress caused decrease in the latency time to enter the dark chamber in male and female new born rats in post-training periods especially the second week compared to the control groups. Conclusion: With regards to the results, prenatal exposure to combined stress can reduce the memory retention of passive avoidance learning.

  1. 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…

  2. Space-time separation during obstacle-avoidance learning in monkeys.

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    Torres, Elizabeth; Andersen, Richard

    2006-11-01

    Is the movement duration time known before we move? To answer this question, a new experimental paradigm is introduced that for the first time monitors the acquisition of a new motor skill in rhesus monkeys. Straight reaches were interleaved with reaches around physical obstacles that elicited a different path geometry. Curved and longer spatial paths were immediately resolved and consistent over months of training. A new temporal strategy separately evolved over repetitions from multiple to a single velocity peak. We propose that the obstacle-avoidance spatial paths were resolved before motion execution and used as reference in the computation of the new dynamics. Path conservation from the first trial occurred both at the hand and at the joint angle levels, whereas the speed profile dramatically changed over time. The spatial solution required no learning and was anticipated by the spontaneous repositioning of the initial arm posture. The learning was in the temporal domain, involving the adjustment of the speed during the motion's first impulse. Within the movement initiation, the partial distance traveled by the hand up to the first velocity peak was finely tuned under a constant time. For a given space location, the time of the first impulse remained robust to learning, but significantly shifted for different targets and obstacle configurations. Differences in the temporal-related parameters across time provided a clear distinction between learning and automatic behavior.

  3. 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…

  4. 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.

  5. The action of orexin B on passive avoidance learning. Involvement of neurotransmitters.

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    Palotai, Miklós; Telegdy, Gyula; Ekwerike, Alphonsus; Jászberényi, Miklós

    2014-10-01

    The extensive projection of orexigenic neurons and the diffuse expression of orexin receptors suggest that endogenous orexins are involved in several physiological functions of the central nervous system, including learning and memory. Our previous study demonstrated that orexin A improves learning, consolidation and retrieval processes, which involves α- and β-adrenergic, cholinergic, dopaminergic, GABA-A-ergic, opiate and nitrergic neurotransmissions. However, we have little evidence about the action of orexin B on memory processes and the underlying neuromodulation. Therefore, the aim of the present study was to investigate the action of orexin B on passive avoidance learning and the involvement of neurotransmitters in this action in rats. Accordingly, rats were pretreated with the selective orexin 2 receptor (OX2R) antagonist, EMPA; the γ-aminobutyric acid subunit A (GABA-A) receptor antagonist, the bicuculline; a D2, D3, D4 dopamine receptor antagonist, haloperidol; the nonselective opioid receptor antagonist, naloxone; the non-specific nitric oxide synthase (NOS) inhibitor, nitro-l-arginine; the nonselective α-adrenergic receptor antagonist, phenoxybenzamine and the β-adrenergic receptor antagonist, propranolol. Our results demonstrate that orexin B can improve learning, consolidation of memory and retrieval. EMPA reversed completely the action of orexin B on memory consolidation. Bicuculline blocked fully; naloxone, nitro-l-arginine, phenoxybenzamine and propranolol attenuated the orexin B-induced memory consolidation, whereas haloperidol was ineffective. These data suggest that orexin B improves memory functions through OX2R and GABA-ergic, opiate, nitrergic, α- and β-adrenergic neurotransmissions are also involved in this action.

  6. Adaptive forgetting in Iberian green frog tadpoles (Pelophylax perezi): learned irrelevance and latent inhibition may avoid predator misidentification.

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    Gonzalo, Adega; López, Pilar; Martín, José

    2013-02-01

    Predator recognition often requires learning by prey individuals. Iberian green frog tadpoles (Pelophylax perezi) have the ability to learn to recognize new potential predators when their chemical cues are found paired with conspecific alarm cues. However, a random pairing of alarm cues and chemical stimuli of a nonpredator might later induce costly antipredator responses to nondangerous species. Here, we studied the potential existence in this frog species of two phenomena (learned irrelevance and latent inhibition) that could help tadpoles to avoid these nonadaptive responses to chemical cues of nonpredator species. Our results showed that, when tadpoles experienced a random pattern of presence of alarm cues alone or predator cues alone over the 4 days before or after the simultaneous detection of these two cues paired, no learned association was formed. These results showed the existence of an effect of learned irrelevance on learning in Iberian green frog tadpoles. Also, tadpoles clearly inhibited the formation of a learning association between predator and alarm cues after a 4-day period during which they had been exposed to the predator cues alone. This result showed the existence of an effect of latent inhibition on learning about cues related to increased predation risk. Thus, both learned irrelevance and latent inhibition, rather than being considered to be failed predator recognition, can rather be seen as adaptive ways for dealing with conflicting information and as strategies to avoid learning irrelevant information and costly antipredatory responses to nonpredatory stimuli.

  7. Inhibitory avoidance learning in zebrafish (Danio rerio): effects of shock intensity and unraveling differences in task performance.

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    Manuel, Remy; Gorissen, Marnix; Roca, Carme Piza; Zethof, Jan; van de Vis, Hans; Flik, Gert; van den Bos, Ruud

    2014-08-01

    The zebrafish (Danio rerio) is increasingly used as a model in neurobehavioral and neuroendocrine studies. The inhibitory avoidance paradigm has been proposed as tool to study mechanisms underlying learning and memory in zebrafish. In this paradigm subjects receive a shock after entering the black compartment of a black-white box. On the next day, latency to enter the black compartment is assessed; higher latencies are indicative of increased avoidance learning. Here, we aimed to understand the effects of different shock intensities (0, 1, 3, and 9 V) and to unravel variation in inhibitory avoidance learning in an in-house reared Tuebingen Long-Fin zebrafish (D. rerio) strain. While median latencies had increased in the 1, 3, and 9 V groups, no increase in median latency was found in the 0 V group. In addition, higher shock intensities resulted in a higher number of avoiders (latency ≥180 s) over nonavoiders (latency zebrafish. These findings serve as starting point for further unraveling differences in brain-behavior relationships underlying (fear avoidance) learning and memory in zebrafish.

  8. The effect of Resveratrol flavonoid on learning and memory in passive avoidance and Y maze in diabetic rat

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    Sima Nasri

    2014-04-01

    Full Text Available Background: Diabetes type I is accompanied with disturbances in cognitive skills, memory and learning. In this research, we evaluated the effect of resveratrol chronic treatment on learning and memory in diabetic male rats. Material and Methods: Rats were divided into 4 groups: control, resveratrol-treated control, diabetic and resveratrol-treated diabetic groups. We used streptozotosin for inducing diabetes. Resveratrol (10mg/kg I.p. was administered for 8 weeks. For evaluation of learning and memory, passive avoidance test and Y-maze task were used. For Statistical analysis, SPSS software and paired T-test and one-way ANOVA were used. Results: Resveratrol decreased serum glucose in diabetic rats (P<0.01. In passive avoidance learning, there wasn’t any significant difference in initial latency between diabetic and treated- diabetic group. Also, a significant decrease of step latency was observed in diabetic and treated diabetic rats (P<0.01. In Y maze, Resveratrol improved alternation percentage in diabetic rats. Conclusion: Probably due to different mechanism of long term and short term memory, long term resveratrol treatment didn’t improve memory and learning in passive avoidance learning. In Y maze, method for determining the spatial memory, resveratrol improved spatial memory in diabetic rats. Resveratrol not only regulates glucose in diabetic rats but also it improves short term memory.

  9. 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.

  10. Effects of histamine and opioid systems on memory retention of passive avoidance learning in rats.

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    Zarrindast, Mohammad-Reza; Eidi, Maryam; Eidi, Akram; Oryan, Shahrbano

    2002-10-04

    The present study investigated the effect of interactions between histamine receptor agents and the opioid peptidergic system on memory retention of passive avoidance learning in rats. Post-training intracerebroventricular (i.c.v.) injections were carried out in all the experiments. Administration of histamine (20 micro g/rat) reduced, but the histamine H(1) receptor antagonist, pyrilamine (20 and 50 micro g/rat), and the histamine H(2) receptor antagonist, cimetidine (10 and 50 micro g/rat), increased memory retention in rats. The histamine receptor antagonists decreased the response induced by histamine. Morphine (1-10 micro g/rat) reduced, while pentazocine (5 and 10 micro g/rat) or the opioid receptor antagonist, naloxone (5 and 15 micro g/rat), increased memory retention. The combination of histamine with morphine showed potentiation. Effects of pyrilamine and cimetidine were attenuated by morphine. The responses to pentazocine and naloxone also were decreased by histamine. It is concluded that the histaminergic system has an interaction with opioidergic system that is involved in the memory retention process.

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

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    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.

  12. Avoiding Misinterpretations of Piaget and Vygotsky: Mathematical Teaching without Learning, Learning without Teaching, or Helpful Learning-Path Teaching?

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    Fuson, Karen C.

    2009-01-01

    This article provides an overview of some perspectives about special issues in classroom mathematical teaching and learning that have stemmed from the huge explosion of research in children's mathematical thinking stimulated by Piaget. It concentrates on issues that are particularly important for less-advanced learners and for those who might be…

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

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    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.

  14. Mechanisms of social avoidance learning can explain the emergence of adaptive and arbitrary behavioral traditions in humans.

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    Lindström, Björn; Olsson, Andreas

    2015-06-01

    Many nonhuman animals preferentially copy the actions of others when the environment contains predation risk or other types of danger. In humans, the role of social learning in avoidance of danger is still unknown, despite the fundamental importance of social learning for complex social behaviors. Critically, many social behaviors, such as cooperation and adherence to religious taboos, are maintained by threat of punishment. However, the psychological mechanisms allowing threat of punishment to generate such behaviors, even when actual punishment is rare or absent, are largely unknown. To address this, we used both computer simulations and behavioral experiments. First, we constructed a model where simulated agents interacted under threat of punishment and showed that mechanisms' (a) tendency to copy the actions of others through social learning, together with (b) the rewarding properties of avoiding a threatening punishment, could explain the emergence, maintenance, and transmission of large-scale behavioral traditions, both when punishment is common and when it is rare or nonexistent. To provide empirical support for our model, including the 2 mechanisms, we conducted 4 experiments, showing that humans, if threatened with punishment, are exceptionally prone to copy and transmit the behavior observed in others. Our results show that humans, similar to many nonhuman animals, use social learning if the environment is perceived as dangerous. We provide a novel psychological and computational basis for a range of human behaviors characterized by the threat of punishment, such as the adherence to cultural norms and religious taboos.

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

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    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.

  16. 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.

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

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    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

  18. Involvement of mu(1)-opioid receptors and cholinergic neurotransmission in the endomorphins-induced impairment of passive avoidance learning in mice.

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    Ukai, Makoto; Lin, Hui Ping

    2002-02-01

    The effects of naloxonazine, a mu(1)-opioid receptor antagonist, and physostigmine, a cholinesterase inhibitor, on the endomorphins-induced impairment of passive avoidance learning were investigated in mice. Endomorphin-1 (10 microg) and endomorphin-2 (10 microg) significantly impaired passive avoidance learning, while naloxonazine (35 mg/kg, s.c.), a mu(1)-opioid receptor antagonist, which alone failed to influence passive avoidance learning significantly inhibited the endomorphin-1 (10 microg)- but not endomorphin-2 (10 microg)-induced disturbance of such learning. A rather nonselective higher dose (50 mg/kg, s.c.) of naloxonazine almost completely antagonized the endomorphin-1 (10 microg)- and endomorphin-2 (10 microg)-induced impairment of passive avoidance learning. In contrast, physostigmine (0.025 and 0.05 mg/kg, i.p.) significantly reversed the endomorphin-1 (10 microg)- and endomorphin-2 (10 microg)-induced disturbance of passive avoidance learning, whereas physostigmine (0.025 and 0.05 mg/kg, i.p.) alone did not influence such learning. These results suggest that endomorphin-1 but not endomorphin-2 impairs learning and memory resulting from cholinergic dysfunction, and from activation of mu(1)-opioid receptors.

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

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    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.

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

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    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.

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

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    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.

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

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    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.

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

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    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.

  4. Functional disconnection of the substantia nigra pars compacta from the pedunculopontine nucleus impairs learning of a conditioned avoidance task.

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    Bortolanza, Mariza; Wietzikoski, Evellyn C; Boschen, Suelen L; Dombrowski, Patricia A; Latimer, Mary; Maclaren, Duncan A A; Winn, Philip; Da Cunha, Claudio

    2010-09-01

    The pedunculopontine tegmental nucleus (PPTg) targets nuclei in the basal ganglia, including the substantia nigra pars compacta (SNc), in which neuronal loss occurs in Parkinson's disease, a condition in which patients show cognitive as well as motor disturbances. Partial loss and functional abnormalities of neurons in the PPTg are also associated with Parkinson's disease. We hypothesized that the interaction of PPTg and SNc might be important for cognitive impairments and so investigated whether disrupting the connections between the PPTg and SNc impaired learning of a conditioned avoidance response (CAR) by male Wistar rats. The following groups were tested: PPTg unilateral; SNc unilateral; PPTg-SNc ipsilateral (ipsilateral lesions in PPTg and SNc); PPTg-SNc contralateral (contralateral lesions in PPTg and SNc); sham lesions (of each type). SNc lesions were made with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine HCl (MPTP, 0.6micromol); PPTg lesions with ibotenate (24nmol). After recovery, all rats underwent 50-trial sessions of 2-way active avoidance conditioning for 3 consecutive days. Rats with unilateral lesions in PPTg or SNc learnt this, however rats with contralateral (but not ipsilateral) combined lesions in both structures presented no sign of learning. This effect was not likely to be due to sensorimotor impairment because lesions did not affect reaction time to the tone or footshock during conditioning. However, an increased number of non-responses were observed in the rats with contralateral lesions. The results support the hypothesis that a functional interaction between PPTg and SNc is needed for CAR learning and performance.

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

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    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.

  6. Electric shock for aversion training of jumping spiders: towards an arachnid model of avoidance learning.

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    Peckmezian, Tina; Taylor, Phillip W

    2015-04-01

    Electric shock is used widely as an aversive stimulus in conditioning experiments, yet little attention has been given to its physiological effects and their consequences for bioassays. In the present study, we provide a detailed characterization of how electric shock affects the mobility and behaviour of Servaea incana, a jumping spider. We begin with four mobility assays and then narrow our focus to a single effective assay with which we assess performance and behaviour. Based on our findings, we suggest a voltage range that may be employed as an aversive stimulus while minimizing decrements in physical performance and other aspects of behaviour. Additionally, we outline a novel method for constructing electric shock platforms that overcome some of the constraints of traditional methods while being highly effective and easily modifiable to suit the study animal and experimental context. Finally, as a demonstration of the viability of our aversive stimulus in a passive avoidance conditioning task, we successfully train spiders to associate a dark compartment with electric shock. Future research using electric shock as an aversive stimulus with terrestrial invertebrates such as spiders and insects may benefit from the flexible and reliable methods outlined in the present study.

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

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    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.

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

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    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

  9. Avoidance of plants unsuitable for the symbiotic fungus in leaf-cutting ants: Learning can take place entirely at the colony dump.

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    Arenas, Andrés; Roces, Flavio

    2017-01-01

    Plants initially accepted by foraging leaf-cutting ants are later avoided if they prove unsuitable for their symbiotic fungus. Plant avoidance is mediated by the waste produced in the fungus garden soon after the incorporation of the unsuitable leaves, as foragers can learn plant odors and cues from the damaged fungus that are both present in the recently produced waste particles. We asked whether avoidance learning of plants unsuitable for the symbiotic fungus can take place entirely at the colony dump. In order to investigate whether cues available in the waste chamber induce plant avoidance in naïve subcolonies, we exchanged the waste produced by subcolonies fed either fungicide-treated privet leaves or untreated leaves and measured the acceptance of untreated privet leaves before and after the exchange of waste. Second, we evaluated whether foragers could perceive the avoidance cues directly at the dump by quantifying the visits of labeled foragers to the waste chamber. Finally, we asked whether foragers learn to specifically avoid untreated leaves of a plant after a confinement over 3 hours in the dump of subcolonies that were previously fed fungicide-treated leaves of that species. After the exchange of the waste chambers, workers from subcolonies that had access to waste from fungicide-treated privet leaves learned to avoid that plant. One-third of the labeled foragers visited the dump. Furthermore, naïve foragers learned to avoid a specific, previously unsuitable plant if exposed solely to cues of the dump during confinement. We suggest that cues at the dump enable foragers to predict the unsuitable effects of plants even if they had never been experienced in the fungus garden.

  10. 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.

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    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.

  11. Deletion of striatal adenosine A(2A) receptor spares latent inhibition and prepulse inhibition but impairs active avoidance learning.

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    Singer, Philipp; Wei, Catherine J; Chen, Jiang-Fan; Boison, Detlev; Yee, Benjamin K

    2013-04-01

    Following early clinical leads, the adenosine A(2A)R receptor (A(2A)R) has continued to attract attention as a potential novel target for treating schizophrenia, especially against the negative and cognitive symptoms of the disease because of A(2A)R's unique modulatory action over glutamatergic in addition to dopaminergic signaling. Through (i) the antagonistic interaction with the dopamine D(2) receptor, and (ii) the regulation of glutamate release and N-methyl-d-aspartate receptor function, striatal A(2A)R is ideally positioned to fine-tune the dopamine-glutamate balance, the disturbance of which is implicated in the pathophysiology of schizophrenia. However, the precise function of striatal A(2A)Rs in the regulation of schizophrenia-relevant behavior is poorly understood. Here, we tested the impact of conditional striatum-specific A(2A)R knockout (st-A(2A)R-KO) on latent inhibition (LI) and prepulse inhibition (PPI) - behavior that is tightly regulated by striatal dopamine and glutamate. These are two common cross-species translational tests for the assessment of selective attention and sensorimotor gating deficits reported in schizophrenia patients; and enhanced performance in these tests is associated with antipsychotic drug action. We found that neither LI nor PPI was significantly affected in st-A(2A)R-KO mice, although a deficit in active avoidance learning was identified in these animals. The latter phenotype, however, was not replicated in another form of aversive conditioning - namely, conditioned taste aversion. Hence, the present study shows that neither learned inattention (as measured by LI) nor sensory gating (as indexed by PPI) requires the integrity of striatal A(2A)Rs - a finding that may undermine the hypothesized importance of A(2A)R in the genesis and/or treatment of schizophrenia.

  12. Effects of heavy particle irradiation and diet on amphetamine- and lithium chloride-induced taste avoidance learning in rats

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    Rabin, Bernard M.; Shukitt-Hale, Barbara; Szprengiel, Aleksandra; Joseph, James A.

    2002-01-01

    Rats were maintained on diets containing either 2% blueberry or strawberry extract or a control diet for 8 weeks prior to being exposed to 1.5 Gy of 56Fe particles in the Alternating Gradient Synchrotron at Brookhaven National Laboratory. Three days following irradiation, the rats were tested for the effects of irradiation on the acquisition of an amphetamine- or lithium chloride-induced (LiCl) conditioned taste avoidance (CTA). The rats maintained on the control diet failed to show the acquisition of a CTA following injection of amphetamine. In contrast, the rats maintained on antioxidant diets (strawberry or blueberry extract) continued to show the development of an amphetamine-induced CTA following exposure to 56Fe particles. Neither irradiation nor diet had an effect on the acquisition of a LiCl-induced CTA. The results are interpreted as indicating that oxidative stress following exposure to 56Fe particles may be responsible for the disruption of the dopamine-mediated amphetamine-induced CTA in rats fed control diets; and that a reduction in oxidative stress produced by the antioxidant diets functions to reinstate the dopamine-mediated CTA. The failure of either irradiation or diet to influence LiCl-induced responding suggests that oxidative stress may not be involved in CTA learning following injection of LiCl.

  13. Externalizing psychopathology and behavioral disinhibition: working memory mediates signal discriminability and reinforcement moderates response bias in approach-avoidance learning.

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    Endres, Michael J; Rickert, Martin E; Bogg, Tim; Lucas, Jesolyn; Finn, Peter R

    2011-05-01

    Research has suggested that reduced working memory capacity plays a key role in disinhibited patterns of behavior associated with externalizing psychopathology. In this study, participants (N = 365) completed 2 versions of a go/no-go mixed-incentive learning task that differed in the relative frequency of monetary rewards and punishments for correct and incorrect active-approach responses, respectively. Using separate structural equation models for conventional (hit and false alarm rates) and signal detection theory (signal discriminability and response bias) performance indices, distinct roles for working memory capacity and changes in payoff structure were found. Specifically, results showed that (a) working memory capacity mediated the effects of externalizing psychopathology on false alarms and discriminability of go versus no-go signals; (b) these effects were not moderated by the relative frequency of monetary rewards and punishments; (c) the relative frequency of monetary rewards and punishments moderated the effects of externalizing psychopathology on hits and response bias for go versus no-go responses; and (d) these effects were not mediated by working memory capacity. The findings implicate distinct roles for reduced working memory capacity and poorly modulated active approach and passive avoidance in the link between externalizing psychopathology and behavioral disinhibition.

  14. 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

  15. 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

  16. 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

  17. 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

  18. 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。

  19. 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

  20. Persons with Mild or Moderate Alzheimer's Disease Learn to Use Urine Alarms and Prompts to Avoid Large Urinary Accidents

    Science.gov (United States)

    Lancioni, Giulio E.; Singh, Nirbhay N.; O'Reilly, Mark F.; Sigafoos, Jeff; Bosco, Andrea; Zonno, Nadia; Badagliacca, Francesco

    2011-01-01

    This study assessed whether three patients with Alzheimer's disease could learn to use urine alarms and caregivers' prompts to eliminate large urinary accidents. As soon as the patient began to release urine, the alarm system presented auditory and vibratory signals. In relation to those signals, the caregiver would prompt/encourage the patient to…

  1. 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.

  2. 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

  3. Influence of morphine- or apomorphine-induced sensitization on histamine state-dependent learning in the step-down passive avoidance test.

    Science.gov (United States)

    Zarrindast, Mohammad-Reza; Khalilzadeh, Azita; Malekmohammadi, Nazanin; Fazli-Tabaei, Soheila

    2006-07-15

    Effects of morphine- or apomorphine-induced sensitization on histamine state-dependent memory of passive avoidance task were examined in mice. Pre-training intracerebroventricular (i.c.v.) administration of histamine (20 microg/mouse) decreased the learning of a one-trial passive avoidance task. Pre-test administration of histamine (10 and 20 microg/mouse) reversed amnesia induced by pre-training of histamine, with maximum response at 20 microg/mouse. Pre-training histamine-induced amnesia was also reversed in morphine- or apomorphine-sensitized mice that had previously received once daily injections of morphine (20 and 30 mg/kg) or apomorphine (0.5 and 1 mg/kg) for 3 days. The reversion of histamine-induced amnesia in morphine-sensitized mice was decreased by once daily administration of naloxone (0.5 and 1 mg/kg), SCH 23390 (0.05 and 0.1 mg/kg) or sulpiride (25, 50 and 100 mg/kg) prior to injection of morphine (30 mg/kg/day, 3 days). Furthermore, once daily administration of sulpiride (50 and 100 mg/kg) but not SCH 23390 (0.01, 0.05 and 0.1 mg/kg) prior to apomorphine (1 mg/kg, for 3 days) decreased the reversion of pre-training histamine-induced amnesia by apomorphine. The results suggest that apomorphine or morphine sensitization affects the impairment of memory induced by histamine and thus it is postulated that opioid and dopamine receptors may play an important role in this effect.

  4. Effects of alpha-adrenoceptor agonists and antagonists on histamine-induced impairment of memory retention of passive avoidance learning in rats.

    Science.gov (United States)

    Zarrindast, Mohammad-Reza; Ahmadi, Ramesh; Oryan, Shahrbanoo; Parivar, Kazem; Haeri-Rohani, Ali

    2002-11-15

    The effect of alpha-adrenoceptor agents on the impairment induced by histamine was measured for memory retention of passive avoidance learning in rats. Post-training intracerebroventricular (i.c.v.) injection was carried out in all the experiments. Histamine (5, 10 and 20 microg/rat) reduced, while a histamine H(1) receptor antagonist, chlorpheniramine (0.1, 1 and 10 microg/rat), increased memory retention. The histamine H(2) receptor antagonist, ranitidine (0.1, 1, 10 and 20 microg/rat), did not elicit any response in this respect. Different doses of chlorpheniramine but not ranitidine reversed the histamine-induced impairment of memory. Clonidine and prazosin decreased, but yohimbine and phenylephrine increased, memory retention. Yohimbine decreased the inhibitory response to histamine. Phenylephrine, clonidine and prazosin did not alter the histamine effect. It is concluded that a histamine-induced impairment of memory retention through histamine H(1) receptors and an alpha(2)-adrenoceptor mechanism may be involved in the histamine response.

  5. 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.

  6. 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…

  7. 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…

  8. 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.

  9. Avoidance-oriented students' development in motivation for maths, self-regulated learning behaviour and achievement: a person-centred study in the lowest level of secondary education

    NARCIS (Netherlands)

    Peetsma, T.; van der Veen, I.

    2013-01-01

    Performance-avoidance orientation has been found to undermine students’ academic motivation and achievement. Recognising groups of students with different levels and developments of performance-avoidance orientation makes it possible to try to intervene early in their school careers. In this study,

  10. 进化操作行为学习模型及在移动机器人避障上的应用%Evolutionary operant behavior learning model and its application to mobile robot obstacle avoidance

    Institute of Scientific and Technical Information of China (English)

    郜园园; 朱凡; 宋洪军

    2013-01-01

    针对移动机器人避障上存在的自适应能力较差的问题,结合遗传算法(GA)的进化思想,以自适应启发评价(AHC)学习和操作条件反射(OC)理论为基础,提出了一种基于进化操作行为学习模型(EOBLM)的移动机器人学习避障行为的方法.该方法是一种改进的AHC学习模式,评价单元采用多层前向神经网络来实现,利用TD算法和梯度下降法进行权值更新,这一阶段学习用来生成取向性信息,作为内在动机决定进化的方向;动作选择单元主要用来优化操作行为以实现状态到动作的最佳映射.优化过程分两个阶段来完成,第一阶段通过操作条件反射学习算法得到的信息熵作为个体适应度,执行GA学习算法搜索最优个体;第二阶段由OC学习算法选择最优个体内的最优操作行为,并得到新的信息熵值.通过移动机器人避障仿真实验,结果表明所设计的EOBLM能使机器人通过不断与外界未知环境进行交互主动学会避障的能力,与传统的AHC方法相比其自学习自适应的能力得到加强.%To solve the problem of poor self-adaptive ability in the robot obstacle avoidance,combined with evolution thought of Genetic Algorithm(GA),an Evolutionary Operant Behavior Learning Model(EOBLM) was proposed for the mobile robot learning obstacle avoidance in unknown environment,which was based on Operant Conditioning(OC) and Adaptive Heuristic Critic(AHC) learning.The proposed model was a modified version of the AHC learning architecture.Adaptive Critic Element(ACE) network was composed of a multi-layer feedforward network and the learning was enhanced by TD(λ)algorithm and gradient descent algorithm.A tropism mechanism was designed in this stage as intrinsic motivation and it could direct the orientation of the Agent learning.Adaptive Selection Element(ASE) network was used to optimize operant behavior to achieve the best mapping from state to actor.The optimizing process has two

  11. 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…

  12. Neural Network-based Q-learning Applied to Obstacle Avoidance in Khepera Ⅱ Mobile Robots%基于神经网络的Q学习在Khepera Ⅱ机器人避障中的应用

    Institute of Scientific and Technical Information of China (English)

    盛维涛; 张文君; 张建兴

    2013-01-01

    为了提高移动机器人的自主学习能力,在传统的机器人行为控制结构基础上设计了智能控制结构,同时引入了基于神经网络的Q学习模块算法,克服了传统算法只能应用到离散状态中的不足.移动机器人的避障实验结果表明,该方法能够使移动机器人通过自学习实现自主避障.%An intelligent control architecture was designed based on a behavior architecture to improve the learning ability of mobile robots.At the same time,a Q-learning algorithm based on a neural network was led into the intelligent control architecture,while normal algorithm can only be applied to discrete states.Experiments of obstacle avoidance show that the mobile robot can learn to avoid obstacles with the algorithm.

  13. Avoiding health information.

    Science.gov (United States)

    Barbour, Joshua B; Rintamaki, Lance S; Ramsey, Jason A; Brashers, Dale E

    2012-01-01

    This study investigated why and how individuals avoid health information to support the development of models of uncertainty and information management and offer insights for those dealing with the information and uncertainty inherent to health and illness. Participants from student (n = 507) and community (n = 418) samples reported that they avoided health information to (a) maintain hope or deniability, (b) resist overexposure, (c) accept limits of action, (d) manage flawed information, (e) maintain boundaries, and (f) continue with life/activities. They also reported strategies for avoiding information, including removing or ignoring stimuli (e.g., avoiding people who might provide health advice) and controlling conversations (e.g., withholding information, changing the subject). Results suggest a link between previous experience with serious illness and health information avoidance. Building on uncertainty management theory, this study demonstrated that health information avoidance is situational, relatively common, not necessarily unhealthy, and may be used to accomplish multiple communication goals.

  14. Exploring the Impact of Individualism and Uncertainty Avoidance in Web-Based Electronic Learning: An Empirical Analysis in European Higher Education

    Science.gov (United States)

    Sanchez-Franco, Manuel J.; Martinez-Lopez, Francisco J.; Martin-Velicia, Felix A.

    2009-01-01

    Our research specifically focuses on the effects of the national cultural background of educators on the acceptance and usage of ICT, particularly the Web as an extensive and expanding information base that provides the ultimate in resource-rich learning. Most research has been used North Americans as subjects. For this reason, we interviewed…

  15. 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

  16. 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)

    2013-08-27

    inhibition, a risk factor for post-traumatic stress disorder (PTSD). Stress 15: 31– 44. 12. Norrholm SD, Jovanovic T, Olin IW, Sands LA, Karapanou I...and punishment learning by serotonin reuptake inhibitors in obsessive - compulsive disorder . Biological Psychiatry 72: 244–250. 26. Biederman J...Opinion in Neurobiology 16: 199–204. 55. Brewin CR, Andrews B, Valentine JD (2000) Meta-analysis of risk factors for posttraumatic stress disorder in

  17. Bird Avoidance Model

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This is an unpublished report on the bird avoidance model to predict bird strike hazards with low flying aircraft. Included is peak periods for different species of...

  18. 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)

  19. 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.

  20. Color-avoiding percolation

    CERN Document Server

    Krause, Sebastian M; Zlatić, Vinko

    2016-01-01

    Many real world networks have groups of similar nodes which are vulnerable to the same failure or adversary. Nodes can be colored in such a way that colors encode the shared vulnerabilities. Using multiple paths to avoid these vulnerabilities can greatly improve network robustness. Color-avoiding percolation provides a theoretical framework for analyzing this scenario, focusing on the maximal set of nodes which can be connected via multiple color-avoiding paths. In this paper we extend the basic theory of color-avoiding percolation that was published in [Krause et. al., Phys. Rev. X 6 (2016) 041022]. We explicitly account for the fact that the same particular link can be part of different paths avoiding different colors. This fact was previously accounted for with a heuristic approximation. We compare this approximation with a new, more exact theory and show that the new theory is substantially more accurate for many avoided colors. Further, we formulate our new theory with differentiated node functions, as s...

  1. Cod avoidance by area regulations in Kattegat

    DEFF Research Database (Denmark)

    Eliasen, Søren Qvist

    2014-01-01

    presents two initiatives for cod avoidance in Kattegat; a fisher initiative sharing information about cod bycatch which could lead to real time closures in areas with high bycatch of juveniles, for vessels with low cod quota to avoid catch of all cod, and a Danish Swedish Government initiative of permanent......The article examines the experiences of two initiatives of cod avoidance by area regulations in the Kattegat in the light of the upcoming discard ban in EU fisheries. The first section highlights elements of the discard ban in the reformed EU Common Fisheries Policy (CFP). The second section...... 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...

  2. 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.

  3. 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.

  4. On partitions avoiding right crossings

    CERN Document Server

    Yan, Sherry H F

    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 avoiding right crossings.

  5. 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.

  6. 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?…

  7. Predicting attention and avoidance: when do avoiders attend?

    Science.gov (United States)

    Klein, Rupert; Knäuper, Bärbel

    2009-09-01

    Three avoidance measures, the Miller Behavioural Style Scale (MBSS), Index of Self-Regulation of Emotion (ISE) and Mainz Coping Inventory (MCI), were compared in their ability to predict attention and avoidance of threats in the emotional Stroop task. It was also examined if the avoidance mechanism of individuals who would normally avoid threat-indicating words becomes disrupted under conditions of dopamine reduction. Results show that only the ISE predicted attention/avoidance of threat-indicating words. In addition, the avoidance mechanism, as measured by the ISE and MCI, was not activated when regular smokers abstained from smoking.

  8. 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.

  9. Avoiding practice development illiteracy

    Directory of Open Access Journals (Sweden)

    Jan

    2016-11-01

    Full Text Available Among other themes, this issue of the IPDJ takes a look at two recent International Practice Development Collaborative (IPDC events: the first-ever virtual international conference in practice development – a marathon event, running as it did over a 24-hour period – and the Enhancing Practice 16 conference held at Queen Margaret University Edinburgh in September. I was fortunate enough to play a part in planning both events. The virtual conference, hosted by the IPDC members at the University of Wollongong, New South Wales, was a massive achievement made possible by a few people who became passionate about the possibilities a virtual global conference could offer. The recordings of the sessions are available online at tinyurl.com/VIPDC-sessions. The Enhancing Practice conference has run every other year since 2001. This year’s event saw a return for some of things we love about these conferences, alongside some new sessions and more creative activities. The 2018 conference will be held in Basel, Switzerland, and hosted by IPDC Swiss practice development network members from Bern and Zurich as well as the host city. Both these events serve as a reminder to us that, in our professional roles and work, relearning is a key part of learning. Many people at conferences spend their time on things that are new or that offer a novel solution to the latest ‘fad’ in healthcare. Having the patience to explore again (and again something we believe we already know is core to lifelong learning. Alvin Toffler (1928-2016 and Heidi Toffler suggest that illiteracy in the 21st century is the inability to learn, unlearn and relearn. Adaptability is an increasingly essential attribute for those working in fast-moving or large organisations. And as Senge (2006 states, our ability to unlearn is essential to our ability to relearn. Further, I would suggest that practice developers also need to learn how others we work with learn, unlearn and relearn, given we

  10. Airborne Collision Avoidance System X

    Science.gov (United States)

    2015-06-01

    avoidance system on behalf of the Federal Aviation Adminis- tration (FAA). The current Traffic Alert and Collision Avoidance System II (TCAS II...transformations to the National Airspace System are being imple- mented through the FAA’s Next-Genera- tion Air Transportation System (NextGen). With the goal...weighted states to provide a single, optimal action. If a collision avoidance This work is sponsored by the Federal Aviation Administration under Air

  11. 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.

  12. Pattern Avoidance in Ternary Trees

    CERN Document Server

    Gabriel, Nathan; Pudwell, Lara; Tay, Samuel

    2011-01-01

    This paper considers the enumeration of ternary trees (i.e. rooted ordered trees in which each vertex has 0 or 3 children) avoiding a contiguous ternary tree pattern. We begin by finding recurrence relations for several simple tree patterns; then, for more complex trees, we compute generating functions by extending a known algorithm for pattern-avoiding binary trees. Next, we present an alternate one-dimensional notation for trees which we use to find bijections that explain why certain pairs of tree patterns yield the same avoidance generating function. Finally, we compare our bijections to known "replacement rules" for binary trees and generalize these bijections to a larger class of trees.

  13. 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...

  14. Things to Avoid When Breastfeeding

    Science.gov (United States)

    ... need to avoid fish that are high in mercury, namely, shark, swordfish, king mackerel, and tilefish. When you do eat fish, it’s important to eat varieties that contain less mercury, such as canned light tuna, shrimp, salmon, pollock, ...

  15. Avoiding Gluten Cross-Contamination

    Science.gov (United States)

    ... Avoiding Gluten Cross-Contamination Reviewed by Sharon Denny, MS, RDN Published April 22, 2014 Print Email You might not think twice about the pot you use to boil water, the plate you put your food on or even the ...

  16. 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.

  17. Approach/avoidance in dreams.

    Science.gov (United States)

    Malcolm-Smith, Susan; Koopowitz, Sheri; Pantelis, Eleni; Solms, Mark

    2012-03-01

    The influential threat simulation theory (TST) asserts that dreaming yields adaptive advantage by providing a virtual environment in which threat-avoidance may be safely rehearsed. We have previously found the incidence of biologically threatening dreams to be around 20%, with successful threat avoidance occurring in approximately one-fifth of such dreams. TST asserts that threat avoidance is over-represented relative to other possible dream contents. To begin assessing this issue, we contrasted the incidence of 'avoidance' dreams with that of their opposite: 'approach' dreams. Because TST states that the threat-avoidance function is only fully activated in ecologically valid (biologically threatening) contexts, we also performed this contrast for populations living in both high- and low-threat environments. We find that 'approach' dreams are significantly more prevalent across both contexts. We suggest these results are more consistent with the view that dreaming is generated by reward-seeking systems than by fear-conditioning systems, although reward-seeking is clearly not the only factor determining the content of dreams.

  18. 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.

  19. 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.

  20. Avoidance: grammatical or semantic causes?

    NARCIS (Netherlands)

    Hulstijn, J.H.; Marchena, E.

    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

  1. 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.

  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. 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.

  4. 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.

  5. 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.

  6. Inhibitory avoidance in CD1 mice: sex matters, as does the supplier.

    Science.gov (United States)

    Parra, Andrés; Rama, Encarnación; Vinader-Caerols, Concepción; Monleón, Santiago

    2013-11-01

    The purpose of the present work was to study possible differences in the learning of inhibitory avoidance (also called passive avoidance) in male and female CD1 mice acquired from three different suppliers, for which a one-trial step-through version of the paradigm was employed. Ninety-six mice from Charles River (France), Janvier (France) and Harlan (The Netherlands) laboratories were divided by sex and assigned to group C, J or H, respectively (n=16). The animals were tested in the training phase (foot-shock: 0.3mA, 5s) and again for avoidance (no foot-shock delivered) one week later. Inhibitory avoidance learning (test latencies significantly higher than training latencies) was observed in every one of the six groups of animals. The variable Supplier was statistically significant, showing better to worse avoidance in C, J and H mice (in that order). A post hoc analysis showed differences between groups C and H. Females tended to exhibit avoidance learning to a greater extent than males. Our results suggest that inhibitory avoidance learning in CD1 mice varies depending on the breeding facilities from which they originate, and that females should be included in inhibitory avoidance studies.

  7. 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…

  8. 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.

  9. 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.

  10. Differences in inhibitory avoidance, cortisol and brain gene expression in TL and AB zebrafish.

    Science.gov (United States)

    Gorissen, M; Manuel, R; Pelgrim, T N M; Mes, W; de Wolf, M J S; Zethof, J; Flik, G; van den Bos, R

    2015-06-01

    Recently, we established an inhibitory avoidance paradigm in Tupfel Long-Fin (TL) zebrafish. Here, we compared task performance of TL fish and fish from the AB strain; another widely used strain and shown to differ genetically and behaviourally from TL fish. Whole-body cortisol and telencephalic gene expression related to stress, anxiety and fear were measured before and 2 h post-task. Inhibitory avoidance was assessed in a 3-day paradigm: fish learn to avoid swimming from a white to a black compartment where a 3V-shock is given: day 1 (first shock), day 2 (second shock) and day 3 (no shock, sampling). Tupfel Long-Fin fish rapidly learned to avoid the black compartment and showed an increase in avoidance-related spatial behaviour in the white compartment across days. In contrast, AB fish showed no inhibitory avoidance learning. AB fish had higher basal cortisol levels and expression levels of stress-axis related genes than TL fish. Tupfel Long-Fin fish showed post-task learning-related changes in cortisol and gene expression levels, but these responses were not seen in AB fish. We conclude that AB fish show higher cortisol levels and no inhibitory avoidance than TL fish. The differential learning responses of these Danio strains may unmask genetically defined risks for stress-related disorders.

  11. Avoidant/Restrictive Food Intake Disorder

    Science.gov (United States)

    ... for the Professional Version Eating Disorders Definition of Eating Disorders Anorexia Nervosa Avoidant/Restrictive Food Intake Disorder Binge Eating ... about what they eat. Eating Disorders Definition of Eating Disorders Anorexia Nervosa Avoidant/Restrictive Food Intake Disorder Binge Eating ...

  12. Allergen avoidance: does it work?

    Science.gov (United States)

    Woodcock, A; Custovic, A

    2000-01-01

    The first recorded example of allergen avoidance in the treatment of allergic disorders dates from the 16th century. The Italian physician Gerolamo Cardano (1501-1576) was invited to Scotland by John Hamilton, Archbishop of St Andrews (and brother of the Regent), to give advice on the treatment of his asthma. Cardano recommended that the Archbishop should get rid of his feather bedding, which was followed by a 'miraculous' remission of otherwise troublesome symptoms. The first controlled attempts to treat asthma by environmental manipulation date to the beginning of 20th century. In 1925, the Leopold brothers treated patients with asthma and other allergic disorders by moving them into a dust free room. Storm van Leeuwen created a 'climate' chamber in The Netherlands in 1927 and demonstrated that asthmatic patients improved when moved from their homes into the chamber. One year later, Dekker observed that measures aimed at reducing the amount of dust in bedrooms had a beneficial effect on asthma symptoms in patients allergic to house dust. Van Leeuwen wrote: 'In our endeavours to find the cause of the attack ... we utilised the known fact that the environment of the asthmatic patient is, as a rule, of primary importance in determining the intensity and frequency of his attacks'. Nowadays, more than ever, it is essential to address the environmental influences on the increasing prevalence of asthma and allergic disorders.

  13. Obstacle avoidance sonar for submarines

    Science.gov (United States)

    Dugas, Albert C.; Webman, Kenneth M.

    2002-05-01

    The Advanced Mine Detection Sonar (AMDS) system was designed to operate in poor environments with high biological and/or shallow-water boundary conditions. It provides increased capability for active detection of volume, close-tethered, and bottom mines, as well as submarine and surface target active/passive detection for ASW and collision avoidance. It also provides bottom topography mapping capability for precise submarine navigation in uncharted littoral waters. It accomplishes this by using advanced processing techniques with extremely narrow beamwidths. The receive array consists of 36 modules arranged in a 15-ft-diameter semicircle at the bottom of the submarine sonar dome to form a chin-mounted array. Each module consists of 40 piezoelectric rubber elements. The modules provide the necessary signal conditioning to the element data prior to signal transmission (uplink) through the hull. The elements are amplified, filtered, converted to digital signals by an A/D converter, and multiplexed prior to uplink to the inboard receiver. Each module also has a downlink over which it receives synchronization and mode/gain control. Uplink and downlink transmission is done using fiberoptic telemetry. AMDS was installed on the USS Asheville. The high-frequency chin array for Virginia class submarines is based on the Asheville design.

  14. 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

  15. 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-than-expected outcomes

  16. Detection And Avoidance Of Obstacles By Helicopters

    Science.gov (United States)

    Cheng, Victor H. L.; Sridhar, Banavar

    1992-01-01

    Report discusses problems relevant to control subsystems enabling helicopters on nap-of-the-Earth flight paths to detect and avoid obstacles automatically. Indicates similarities between this and obstacle-avoidance problem of industrial mobile robots. Two approaches extend two-dimensional obstacle-avoidance concept to three dimensions. First involves direct search of three-dimensional range-map data for indications of openings between obstacles. Second involves compression of data into two-dimensional map for path search.

  17. Mobile Robot Collision Avoidance in Human Environments

    OpenAIRE

    Lingqi Zeng; Gary M. Bone

    2013-01-01

    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....

  18. 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

  19. 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

  20. 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...

  1. 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...

  2. 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…

  3. [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 < 0.01 or P < 0.05). Fast Fourier transform showed that percentage increase of 0-10 Hz band occurred mainly in θ (3-7 Hz) frequency, and 30-40 Hz frequency change was equivalent to the γ1 band. Furthermore, compared with those before training, only the percentages of β, β2 (20-30 Hz) and γ1 rhythm increased (P < 0.01 or P < 0.05) in fast 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 < 0.01). These results suggest that the increased percentages of β2 and γ1 rhythm and high-level (unchanged) percentage of θ rhythm in the right hippocampus CA3 area might be related to strong spatial cognition ability of fast avoidance response rats.

  4. Obstacle Avoidance of a Mobile Robot with Hierarchical Structure

    Energy Technology Data Exchange (ETDEWEB)

    Park, Chan Gyu [Yeungnam College of Science and Technolgy, Taegu (Korea)

    2001-06-01

    This paper proposed a new hierarchical fuzzy-neural network algorithm for navigation of a mobile robot within unknown dynamic environment. Proposed navigation algorithm used the learning ability of the neural network and the feasibility of control highly nonlinear system of fuzzy theory. The proposed navigation algorithm used fuzzy algorithm for goal approach and fuzzy-network for effective collision avoidance. Some computer simulation results for a mobile robot equipped with ultrasonic range sensors show that the suggested navigation algorithm is very effective to escape in stationary and moving obstacles environment. (author). 11 refs., 14 figs., 2 tabs.

  5. 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

  6. 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

  7. 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...

  8. No discrimination shock avoidance with sequential presentation of stimuli but shore crabs still reduce shock exposure.

    Science.gov (United States)

    Magee, Barry; Elwood, Robert W

    2016-07-15

    Insights into the potential for pain may be obtained from examination of behavioural responses to noxious stimuli. In particular, prolonged responses coupled with long-term motivational change and avoidance learning cannot be explained by nociceptive reflex but are consistent with the idea of pain. Here, we placed shore crabs alternately in two halves of a test area divided by an opaque partition. Each area had a dark shelter and in one repeated small electric shocks were delivered in an experimental but not in a control group. Crabs showed no specific avoidance of the shock shelter either during these trials or in a subsequent test in which both were offered simultaneously; however they often emerged from the shock shelter during a trial and thus avoided further shock. More crabs emerged in later trials and took less time to emerge than in early trials. Thus, despite the lack of discrimination learning between the two shelters they used other tactics to markedly reduce the amount of shock received. We note that a previous experiment using simultaneous presentation of two shelters demonstrated rapid discrimination and avoidance learning but the paradigm of sequential presentation appears to prevent this. Nevertheless, the data show clearly that the shock is aversive and tactics, other than discrimination learning, are used to avoid it. Thus, the behaviour is only partially consistent with the idea of pain.

  9. 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.

  10. Foods to Avoid or Limit during Pregnancy

    Science.gov (United States)

    ... report card Careers Archives Pregnancy Before or between pregnancies Nutrition, weight & fitness Prenatal care Is it safe? Labor & ... more. Stony Point, NY 10980 Close X Home > Pregnancy > Nutrition, weight & fitness > Foods to avoid or limit during ...

  11. 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...

  12. 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...

  13. Avoid the Consequences of High Blood Pressure

    Science.gov (United States)

    ... Thromboembolism Aortic Aneurysm More Avoid the Consequences of High Blood Pressure Infographic Updated:Oct 31,2016 View a downloadable version of this infographic High Blood Pressure • Home • Get the Facts About HBP • Know Your ...

  14. Your Adolescent: Anxiety and Avoidant Disorders

    Science.gov (United States)

    ... other times, it develops into panic attacks and phobias. Identifying the Signs Anxiety disorders vary from teenager ... may begin to avoid normal activities and routines. Phobias Many fears of younger children are mild, passing, ...

  15. USAID IT Reform Cost Savings/Avoidance

    Data.gov (United States)

    US Agency for International Development — The Office of the Chief Information Officer in the Management Bureau of USAID launched initiatives designed for IT cost savings and avoidance. This dataset includes...

  16. 6 Tips to Avoid Medication Mistakes

    Science.gov (United States)

    ... For Consumers Consumer Updates 6 Tips to Avoid Medication Mistakes Share Tweet Linkedin Pin it More sharing ... dietary supplements you use. back to top Computerized Medication Box FDA has cleared for marketing the Electronic ...

  17. 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...

  18. Temporal and spatial strategies in an active place avoidance task on Carousel: a study of effects of stability of arena rotation speed in rats

    Directory of Open Access Journals (Sweden)

    Štěpán Bahník

    2015-09-01

    Full Text Available The active place avoidance task is a dry-arena task used to assess spatial navigation and memory in rodents. In this task, a subject is put on a rotating circular arena and avoids an invisible sector that is stable in relation to the room. Rotation of the arena means that the subject’s avoidance must be active, otherwise the subject will be moved in the to-be-avoided sector by the rotation of the arena and a slight electric shock will be administered. The present experiment explored the effect of variable arena rotation speed on the ability to avoid the to-be-avoided sector. Subjects in a group with variable arena rotation speed learned to avoid the sector with the same speed and attained the same avoidance ability as rats in a group with a stable arena rotation speed. Only a slight difference in preferred position within the room was found between the two groups. No difference was found between the two groups in the dark phase, where subjects could not use orientation cues in the room. Only one rat was able to learn the avoidance of the to-be-avoided sector in this phase. The results of the experiment suggest that idiothetic orientation and interval timing are not crucial for learning avoidance of the to-be-avoided sector. However, idiothetic orientation might be sufficient for avoiding the sector in the dark.

  19. The vigilance-avoidance model of avoidant recognition: An ERP study under threat priming.

    Science.gov (United States)

    Zhai, Jing; Chen, Xu; Ma, Jianling; Yang, Qingqing; Liu, Ying

    2016-12-30

    Our study examined attachment-related electrophysiological differences in recognition using event-related potentials (ERPs) measured during a study-test paradigm after threat priming. We identified ERP correlates of recognition by comparing the ERPs of attachment-related positive and negative images between avoidant and secure attachment orientations. Our results revealed that the distribution of early old/new effects was broader in avoidant individuals than in secure individuals, and an early parietal old/new effect was observed in avoidant individuals, which reflected their implicit memory. The late old/new effect was found only in secure individuals when evoked by negative pictures, and was not observed in avoidant individuals. The results suggest that avoidant individuals adopt the "vigilance-avoidance" dual-process model to recognize both positive and negative attachment-related stimuli and carry out preferential familiarity matching at the automatic level and avoidant retrieval at the controlled-processing level.

  20. 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....

  1. EDITORIAL AVOIDABLE MORTALITY OF SCIENTIFIC MANUSCRIPTS

    Directory of Open Access Journals (Sweden)

    Mauricio Palacios

    2010-06-01

    during any of the editorial phases should not occur. Elaborating a manuscript to be submitted for publication requires time; nevertheless, accepting or discussing evaluating peer observations and sending a corrected version requires dedication, proportionally smaller, when compared to the initial effort. Editorial processes contain a high degree of critique and this should not offend the authors; there is also no limit number of versions when we are seeking for the best possible document. A useful attitude for this editorial phase is to delegate, from the very beginning, a leader responsible in following the document’s progress; the natural choice here is the author who wrote the manuscript to maintain the style and for said individual to coordinate the changes made with the other collaborators. The editorial board will always be available to address questions or discuss any aspect of the elaboration of the final draft of the document.Deficiencies in composition are part of the natural course of learning how to write. Higher education is focused on the student understanding a written text, not on the student drafting such and formation processes in this aspect for researchers in the field of health are almost nonexistent. Writing requires a mentor and dedicated practice. For this reason, we will suggest consulting the work of Cassany4 an expert guide on writing construction.Lastly, there are virtues that avoid editorial mortality. Recognizing oneself as an imperfect writer promotes the practice of reviewing our texts amongst peers, even among those not involved in the issue; if they understand what we write, we are improving. We should remember that the worst manuscript is the one we never get to write and that only those who have never written scientific articles have never had a manuscript rejected.

  2. EDITORIAL AVOIDABLE MORTALITY OF SCIENTIFIC MANUSCRIPTS

    Directory of Open Access Journals (Sweden)

    Mauricio Palacios

    2010-06-01

    during any of the editorial phases should not occur. Elaborating a manuscript to be submitted for publication requires time; nevertheless, accepting or discussing evaluating peer observations and sending a corrected version requires dedication, proportionally smaller, when compared to the initial effort. Editorial processes contain a high degree of critique and this should not offend the authors; there is also no limit number of versions when we are seeking for the best possible document. A useful attitude for this editorial phase is to delegate, from the very beginning, a leader responsible in following the document’s progress; the natural choice here is the author who wrote the manuscript to maintain the style and for said individual to coordinate the changes made with the other collaborators. The editorial board will always be available to address questions or discuss any aspect of the elaboration of the final draft of the document. Deficiencies in composition are part of the natural course of learning how to write. Higher education is focused on the student understanding a written text, not on the student drafting such and formation processes in this aspect for researchers in the field of health are almost nonexistent. Writing requires a mentor and dedicated practice. For this reason, we will suggest consulting the work of Cassany4 an expert guide on writing construction. Lastly, there are virtues that avoid editorial mortality. Recognizing oneself as an imperfect writer promotes the practice of reviewing our texts amongst peers, even among those not involved in the issue; if they understand what we write, we are improving. We should remember that the worst manuscript is the one we never get to write and that only those who have never written scientific articles have never had a manuscript rejected.

  3. 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.

  4. ADVERTISING AVOIDANCE PADA IKLAN DI MEDIA TELEVISI

    Directory of Open Access Journals (Sweden)

    Indah Dwi Pratama

    2016-01-01

    Full Text Available One factor that can interfere with the absorption rate of viewers on television advertisement is advertising avoidance which shows the difference between the number of viewers who watch advertisement programs and the number of viewers who watch television programs. The factors that affect advertising avoidance include the demography of the viewers (gender, age, area of residence, and social economic status, or SES, advertising attributes (the television stations, order of ads, genre of the program, and advertising sector, and competition (DayPart. The study attempted to measure the level of advertising avoidance in Indonesia and its relation to various factors that influence it by using the secondary data generated by Nielsen Audience Measurement Indonesia through Television Audience Measurement (TAM. The methods utilized consisted of the t-test independent sample, one way ANOVA, Tukey, Kruskal Wallis, and Dunn Bonferoni. The result showed that the level of advertising avoidance in Indonesia reached by 23%, with relatively similar results to the other studies in various countries. The hypothesis test results also showed a significant relationship between the advertising avoidance and demographic variables, advertising attributes, and competitions affecting this avoidance. On one hand, the findings of the study are expected to be useful for the advertisers to plan their advertisements on television so that they become more effective and efficient. On the other hand, television stations can utilize these findings as a development strategy to expand their audience segmentation and to accommodate the needs of the advertisers more optimally.Keywords: advertising avoidance, television advertisement, TAM, ANOVA, Tukey

  5. Chloroplast avoidance movement reduces photodamage in plants.

    Science.gov (United States)

    Kasahara, Masahiro; Kagawa, Takatoshi; Oikawa, Kazusato; Suetsugu, Noriyuki; Miyao, Mitsue; Wada, Masamitsu

    When plants are exposed to light levels higher than those required for photosynthesis, reactive oxygen species are generated in the chloroplasts and cause photodamage. This can occur even under natural growth conditions. To mitigate photodamage, plants have developed several protective mechanisms. One is chloroplast avoidance movement, in which chloroplasts move from the cell surface to the side walls of cells under high light conditions, although experimental support is still awaited. Here, using different classes of mutant defective in chloroplast avoidance movement, we show that these mutants are more susceptible to damage in high light than wild-type plants. Damage of the photosynthetic apparatus and subsequent bleaching of leaf colour and necrosis occur faster under high light conditions in the mutants than in wild-type plants. We conclude that chloroplast avoidance movement actually decreases the amount of light absorption by chloroplasts, and might therefore be important to the survival of plants under natural growth conditions.

  6. 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.

  7. 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.

  8. Telerobotics with whole arm collision avoidance

    Energy Technology Data Exchange (ETDEWEB)

    Wilhelmsen, K.; Strenn, S.

    1993-09-01

    The complexity of teleorbotic operations in a cluttered environment is exacerbated by the need to present collision information to the operator in an understandable fashion. In addition to preventing movements which will cause collisions, a system providing some form of virtual force reflection (VFR) is desirable. With this goal in mind, Lawrence Livermore National Laboratory (LLNL) has installed a kinematically master/slave system and developed a whole arm collision avoidance system which interacts directly with the telerobotic controller. LLNL has also provided a structure to allow for automated upgrades of workcell models and provide collision avoidance even in a dynamically changing workcell.

  9. Avoidance-based human Pavlovian-to-instrumental transfer.

    Science.gov (United States)

    Lewis, Andrea H; Niznikiewicz, Michael A; Delamater, Andrew R; Delgado, Mauricio R

    2013-12-01

    The Pavlovian-to-instrumental transfer (PIT) paradigm probes the influence of Pavlovian cues over instrumentally learned behavior. The paradigm has been used extensively to probe basic cognitive and motivational processes in studies of animal learning. More recently, PIT and its underlying neural basis have been extended to investigations in humans. These initial neuroimaging studies of PIT have focused on the influence of appetitively conditioned stimuli on instrumental responses maintained by positive reinforcement, and highlight the involvement of the striatum. In the current study, we sought to understand the neural correlates of PIT in an aversive Pavlovian learning situation when instrumental responding was maintained through negative reinforcement. Participants exhibited specific PIT, wherein selective increases in instrumental responding to conditioned stimuli occurred when the stimulus signaled a specific aversive outcome whose omission negatively reinforced the instrumental response. Additionally, a general PIT effect was observed such that when a stimulus was associated with a different aversive outcome than was used to negatively reinforce instrumental behavior, the presence of that stimulus caused a non-selective increase in overall instrumental responding. Both specific and general PIT behavioral effects correlated with increased activation in corticostriatal circuitry, particularly in the striatum, a region involved in cognitive and motivational processes. These results suggest that avoidance-based PIT utilizes a similar neural mechanism to that seen with PIT in an appetitive context, which has implications for understanding mechanisms of drug-seeking behavior during addiction and relapse.

  10. 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.

  11. 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…

  12. 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…

  13. 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.

  14. 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.

  15. 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.

  16. From Affective Experience to Motivated Action : Tracking Reward-Seeking and Punishment-Avoidant Behaviour in Real-Life

    NARCIS (Netherlands)

    Wichers, Marieke; Kasanova, Zuzana; Bakker, Jindra; Thiery, Evert; Derom, Catherine; Jacobs, Nele; van Os, Jim

    2015-01-01

    Many of the decisions and actions in everyday life result from implicit learning processes. Important to psychopathology are, for example, implicit reward-seeking and punishment-avoidant learning processes. It is known that when specific actions get associated with a rewarding experience, such as po

  17. Development of a Measure of Experiential Avoidance: The Multidimensional Experiential Avoidance Questionnaire

    Science.gov (United States)

    Gamez, Wakiza; Chmielewski, Michael; Kotov, Roman; Ruggero, Camilo; Watson, David

    2011-01-01

    Experiential avoidance (EA) has been conceptualized as the tendency to avoid negative internal experiences and is an important concept in numerous conceptualizations of psychopathology as well as theories of psychotherapy. Existing measures of EA have either been narrowly defined or demonstrated unsatisfactory internal consistency and/or evidence…

  18. 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 ...

  19. 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.

  20. The Netherlands Bird Avoidance Model, Final Report

    NARCIS (Netherlands)

    Shamoun-Baranes, J.; Bouten, W.; Sierdsema, H.; van Belle, J.; van Gasteren, J.R.; van Loon, E.E.

    2006-01-01

    The NL-BAM was developed as a web-based decision support tool to be used by the bird hazard avoidance experts in the ecology unit of the Royal Netherlands Air Force. The NL-BAM will be used together with the ROBIN 4 radar system to provide BirdTAMS, for real time warnings and flight planning and to

  1. 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.

  2. 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

  3. [Avoidance of patient-prosthesis mismatch].

    Science.gov (United States)

    Sakamoto, Y; Hashimoto, K

    2006-04-01

    To minimize the incidence of patient-prosthesis mismatch (PPM), we have routinely adopted aortic root enlargement to avoid PPM for patients with small aortic annulus. The aim of this study was to review our strategy of avoiding PPM. The Carpentier-Edwards Perimount (CEP) valves were implanted in 53 patients who were mostly aged over 65 and the St. Jude Medical (SJM) mechanical valves were used in 128 patients aged under 65. A standard 21-mm SJM valve was used in only 3 patients and no 19-mm valves were employed. However, 19-mm CEP valves were used in 12 patients with a small body surface area (1.43 +/- 0.14 m2). Of these, 26 patients (14.4%) who had a small aortic annulus and 24 patients aged under 65 underwent aortic root enlargement. No patient receiving an SJM valve had an projected indexed effective orifice area (EOAI) small annulus, the first choice for avoiding PPM is aortic annular enlargement, which may be avoided by high performance mechanical valves with larger EOA.

  4. 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.…

  5. Avoidable costs of comprehensive case management.

    Science.gov (United States)

    Issel, L M; Anderson, R A

    1999-01-01

    Comprehensive case management has become an industry standard and its pervasiveness raises questions about the ubiquitous need for this service. Analyzed from the perspective of transaction cost analysis and access, we argue that in some cases comprehensive case management is an avoidable cost incurred because of system problems that limit access to otherwise eligible clients. Implications are discussed.

  6. 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.

  7. 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

  8. 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.

  9. 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...

  10. Reducing avoidable pressure ulcers in the community.

    Science.gov (United States)

    Parnham, Alison; Pankhurst, Sarah; Dabell, Wendy

    2015-02-27

    The elimination of avoidable pressure ulcers remains a challenge in healthcare provision, represents an increasing financial burden on resources and continues to affect patients' quality of life. Many pressure ulcers are deemed to be avoidable and there are several factors that can influence this, including the development of a care delivery system and a service delivery strategy that incorporate a comprehensive structure, a meticulous process and measurable outcomes. Nottingham CityCare developed a strategy to reduce avoidable pressure ulcers. The implementation of the strategy in an inner city community setting is discussed. The importance of eliminating pressure ulcers is explored, and the barriers to care delivery are reviewed, demonstrating how a new culture in clinical practice can ensure the elimination of avoidable pressure ulcers. The challenges within the implementation process are reflected on and the implementation of the SSKIN (Surface, Skin inspection, Keep your patient moving, Incontinence and moisture, Nutrition and hydration) phenomenon is reviewed in relation to care delivery, record-keeping and evaluation.

  11. 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

  12. Don't look now! Oculomotor avoidance as a conditioned disgust response.

    Science.gov (United States)

    Armstrong, Thomas; McClenahan, Laura; Kittle, Jody; Olatunji, Bunmi O

    2014-02-01

    Pavlovian conditioning paradigms have revealed fear learning tendencies that may be implicated in the etiology and maintenance of anxiety disorders. Given the prominence of disgust in certain anxiety disorders, it may be fruitful to study disgust learning in addition to fear learning. The present study utilized eye tracking to examine the effects of disgust conditioning on attentional bias, a phenomenon that characterizes anxiety disorders. Participants completed either a disgust condition, in which a face (conditioned stimulus; CS+) was paired with videos of individuals vomiting (unconditioned stimulus; US), or a negative condition in which a face was paired with videos of individuals being harmed in motor-vehicle accidents. Eye movements were used to measure attentional biases related to the USs and the CSs. In line with prior research, attentional avoidance was observed for the disgust CS+. However, this effect did not reach significance until after extinction and was linked to self-reported disgust postacquisition, yet decoupled from self-reported disgust postextinction. Attentional avoidance of the CS+ was not found in the negative condition, and postextinction differences in attentional bias for the CS+ between conditions were found to be mediated by differences in attentional bias for the US, as only the disgust US elicited attentional avoidance. Also, individual differences in disgust sensitivity were found to be associated with attentional avoidance of the disgust US, and this effect was mediated by self-reported disgust in response to the US. Further, disgust sensitivity was associated with attentional avoidance of the disgust CS+, and this effect was mediated by attentional avoidance of the disgust US. These findings provide new insight into a complex pattern of relations between disgust, evaluative learning, and attention that may have implications for the etiology and maintenance of certain anxiety disorders.

  13. Performance-approach and performance-avoidance goals: when uncertainty makes a difference.

    Science.gov (United States)

    Darnon, Céline; Harackiewicz, Judith M; Butera, Fabrizio; Mugny, Gabriel; Quiamzade, Alain

    2007-06-01

    Performance-avoidance goals (the desire to avoid performing more poorly than others do) have been shown to have consistently deleterious effects on performance but the effects of performance-approach goals (trying to outperform others) are more complex. Two studies examine uncertainty as a moderator of the effect of performance-approach goals on performance. Experiment 1 shows that manipulated performance-approach goals lead to better performance than do performance-avoidance goals in the absence of uncertainty about performance but when participants learn that a coactor disagreed with them about problem solutions, creating uncertainty, performance-approach goals do not differ from performance-avoidance goals in their effect on performance. Experiment 2 shows that uncertainty also moderates the effects of self-set performance-approach goals. Moreover, the same dynamic occurs with another kind of uncertainty: negative competence feedback.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Piracetam counteracts the effects of amitriptyline on inhibitory avoidance in CD1 mice.

    Science.gov (United States)

    Everss, Estrella; Arenas, M Carmen; Vinader-Caerols, Concepción; Monleón, Santiago; Parra, Andrés

    2005-04-30

    The purpose of the present work was to study the effects of amitriptyline on animal cognition in relation to some characteristics of its therapeutic effects. The modulation of acute and chronic effects of amitriptyline on inhibitory avoidance in male and female mice by piracetam was investigated. In Experiment 1, mice were subjected to the training phase of inhibitory avoidance conditioning 60 min after acute piracetam (100 mg/kg) or physiological saline administration. Immediately after the behavioural task, they received a single injection of the tricyclic antidepressant amitriptyline (30 mg/kg) or physiological saline. Twenty-four hours later, subjects were tested for avoidance. In Experiment 2, the same doses of amitriptyline and piracetam were chronically administered. Mice were subjected to the training phase of inhibitory avoidance on the 22nd day, and to the test phase 24 h later. Forty-five minutes after test, subjects explored the elevated plus-maze for 5 min in order to assess whether the effects of amitriptyline on avoidance performance may reflect general behavioural changes. Results obtained were that: (a) acute and chronic amitriptyline impaired inhibitory avoidance of male and female mice, (b) piracetam counteracted the effect of acutely administered amitriptyline on inhibitory avoidance, and (c) piracetam counteracted the effects of chronically administered amitriptyline in males but not females in the same learning task. These effects do not seem to be mediated by non-specific drug effects on spontaneous motor activity or anxiety.

  19. 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.

  20. How to Avoid Severe Incidents at Pumped Storage Power Plants

    Science.gov (United States)

    Yasuda, Masashi; Watanabe, Satoshi

    2016-11-01

    Pumped storage is now increasing its importance as the most powerful and reliable tool for stabilizing the electrical network, especially under the increase of intermittent power sources like wind-power and solar-power. However, pumped storage power plants have generally more machinery troubles than the conventional hydropower plants and sometimes they encountered unexpected severe incidents having long-term outage and a considerable restoration cost. The present paper provides some study results about general tendencies of machinery troubles in pumped storage, some examples of severe incidents mainly about the electro-mechanical troubles but also about the flood and fire, and possible scenarios which may lead into a severe result. Finally, it provides lessons learned and some recommendations to avoid severe incidents based on experiences.

  1. 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)

  2. A parametric study of the effects of the noradrenaline neurotoxin DSP4 on avoidance acquisition and noradrenaline neurones in the CNS of the rat.

    OpenAIRE

    Archer, T.; G Jonsson; Ross, S. B.

    1984-01-01

    The effects of various doses of DSP4 on two-way active avoidance acquisition in rats and on central noradrenaline neurones were compared. Doses of DSP4 from 3 mg kg-1 i.p. and upwards injected one week before the onset of the avoidance trials significantly impaired two-way avoidance learning. The learning impairment caused by DSP4 (50 mg kg-1 i.p.) lasted for at least 10 weeks. Desipramine (20 mg kg-1) injected either 30 or 60 min before DSP4 (50 mg kg-1) antagonized the active avoidance impa...

  3. 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.

  4. Information Dilemmas and Blame-Avoidance Strategies

    DEFF Research Database (Denmark)

    Erik, Baekkeskov; Rubin, Olivier

    2016-01-01

    China and other authoritarian states notoriously keep mum about disasters. Yet two recent but dissimilar Chinese responses to infectious disease epidemics show that authoritarian crisis management can shift from secrecy to openness. China maintained prolonged secrecy during 2003 SARS, yet was open...... 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...... on information control to insulating leaders by using technical experts and agencies as “lightning rods.” In 2003, the Chinese strategy of information containment and secrecy backfired, and the Chinese leadership eventually received blame at home and internationally for crisis mismanagement. In 2009, China put...

  5. How to avoid deferred-compensation troubles.

    Science.gov (United States)

    Freeman, Todd I

    2005-06-01

    Executive compensation packages have long included stock options and deferred compensation plans in order to compete for talent. Last year, Congress passed a law in response to the Enron debacle, in which executives were perceived to be protecting their deferred compensation at the expense of employees, creditors, and investors. The new law is designed to protect companies and their shareholders from being raided by the very executives that guided the company to financial ruin. Physicians who are part owners of medical practices need to know about the changes in the law regarding deferred compensation and how to avoid costly tax penalties. This article discusses how the changes affect medical practices as well as steps physician-owned clinics can take to avoid the risk of penalty, such as freezing deferred compensation and creating a new deferred compensation plan.

  6. 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.

  7. 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...

  8. 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

  9. Potentially Avoidable Peripartum Hysterectomies in Denmark

    DEFF Research Database (Denmark)

    Colmorn, Lotte Berdiin; Krebs, Lone; Langhoff-Roos, Jens

    2016-01-01

    to minimize the number of unnecessary peripartum hysterectomies, obstetricians and anesthesiologists should investigate individual cases by structured clinical audit, and disseminate and discuss the results for educational purposes. An international collaboration is warranted to strengthen our recommendations......OBJECTIVE: To audit the clinical management preceding peripartum hysterectomy and evaluate if peripartum hysterectomies are potentially avoidable and by which means. MATERIAL AND METHODS: We developed a structured audit form based on explicit criteria for the minimal mandatory management...

  10. 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/

  11. Acute carbon dioxide avoidance in Caenorhabditis elegans

    OpenAIRE

    Hallem, Elissa A.; Sternberg, Paul W.

    2008-01-01

    Carbon dioxide is produced as a by-product of cellular respiration by all aerobic organisms and thus serves for many animals as an important indicator of food, mates, and predators. However, whether free-living terrestrial nematodes such as Caenorhabditis elegans respond to CO2 was unclear. We have demonstrated that adult C. elegans display an acute avoidance response upon exposure to CO2 that is characterized by the cessation of forward movement and the rapid initiation of backward movement....

  12. How does a cyclist avoid obstacles?

    Science.gov (United States)

    Miyadait, Masayuki; Uetake, Teruo; Shimoda, Masahiro

    2012-12-01

    The purpose of this research is to examine the ways bicycles swerve off sidewalks onto roads under various conditions. Seven students, five males and two females participated in an experiment on a road with a 100-cm wide sidewalk. Footage of each participant on a bicycle evading obstacles such as a utility pole and pedestrian were taken with a video camera, while a front-wheel view of the path taken by the bicycle was recorded simultaneously with a digital camera. Twelve experimental conditions were used for each participant, consisting of all the combinations of (1) three obstacle types, (2) the side (left or right) to which the bicycle went to avoid the obstacle, and (3) two weather conditions. Based on the two recorded scenes, the path was then analyzed from the viewpoint of how the bicycle swerved to avoid hitting the obstacle. We found that the conditions of riding a bicycle with an umbrella caused a larger swerve to avoid the obstacle than those conditions when the rider did not have an umbrella. In particular, the condition in which the obstacle was a pedestrian who also had an umbrella caused the largest swerve. Furthermore, the distance required to become aligned with the sidewalk when the obstacle was a pedestrian walking toward the cyclist was longer than that for other obstacles. The swerve width data showed interesting results, including a tendency for swerve width to be wider when the obstacle was a utility pole compared with other obstacles.

  13. 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.

  14. 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.

  15. 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.

  16. Acute carbon dioxide avoidance in Caenorhabditis elegans.

    Science.gov (United States)

    Hallem, Elissa A; Sternberg, Paul W

    2008-06-10

    Carbon dioxide is produced as a by-product of cellular respiration by all aerobic organisms and thus serves for many animals as an important indicator of food, mates, and predators. However, whether free-living terrestrial nematodes such as Caenorhabditis elegans respond to CO2 was unclear. We have demonstrated that adult C. elegans display an acute avoidance response upon exposure to CO2 that is characterized by the cessation of forward movement and the rapid initiation of backward movement. This response is mediated by a cGMP signaling pathway that includes the cGMP-gated heteromeric channel TAX-2/TAX-4. CO2 avoidance is modulated by multiple signaling molecules, including the neuropeptide Y receptor NPR-1 and the calcineurin subunits TAX-6 and CNB-1. Nutritional status also modulates CO2 responsiveness via the insulin and TGFbeta signaling pathways. CO2 response is mediated by a neural circuit that includes the BAG neurons, a pair of sensory neurons of previously unknown function. TAX-2/TAX-4 function in the BAG neurons to mediate acute CO2 avoidance. Our results demonstrate that C. elegans senses and responds to CO2 using multiple signaling pathways and a neural network that includes the BAG neurons and that this response is modulated by the physiological state of the worm.

  17. 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.

  18. 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.

  19. 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.

  20. 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...

  1. Avoiding unseen obstacles: Subcortical vision is not sufficient to maintain normal obstacle avoidance behaviour during reaching.

    Science.gov (United States)

    Ross, Alasdair I; Schenk, Thomas; Billino, Jutta; Macleod, Mary J; Hesse, Constanze

    2016-10-03

    Previous research found that a patient with cortical blindness (homonymous hemianopia) was able to successfully avoid an obstacle placed in his blind field, despite reporting no conscious awareness of it [Striemer, C. L., Chapman, C. S., & Goodale, M. A., 2009, PNAS, 106(37), 15996-16001]. This finding led to the suggestion that dorsal stream areas, that are assumed to mediate obstacle avoidance behaviour, may obtain their visual input primarily from subcortical pathways. Hence, it was suggested that normal obstacle avoidance behaviour can proceed without input from the primary visual cortex. Here we tried to replicate this finding in a group of patients (N = 6) that suffered from highly circumscribed lesions in the occipital lobe (including V1) that spared the subcortical structures that have been associated with action-blindsight. We also tested if obstacle avoidance behaviour differs depending on whether obstacles are placed only in the blind field or in both the blind and intact visual field of the patients simultaneously. As expected, all patients successfully avoided obstacles placed in their intact visual field. However, none of them showed reliable avoidance behaviour - as indicated by adjustments in the hand trajectory in response to obstacle position - for obstacles placed in their blind visual field. The effects were not dependent on whether one or two obstacles were present. These findings suggest that behaviour in complex visuomotor tasks relies on visual input from occipital areas.

  2. The influence of mastery-avoidance goals on performance improvement

    NARCIS (Netherlands)

    Van Yperen, Nico W.; Elliot, Andrew J.; Anseel, Frederik

    2009-01-01

    Two experiments focused on examining the influence of mastery-avoidance goals on performance improvement, and more specifically, on mastery-avoidance goals grounded in an intrapersonal standard. That is, herein, mastery-avoidance goals entail striving to avoid doing worse than one has done before. B

  3. 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

    2014-12-03

    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.

  4. 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.

  5. 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

  6. 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.

  7. Tax Anti-avoidance Through Transfer Pricing

    DEFF Research Database (Denmark)

    Rossing, Christian Plesner; Riise Johansen, Thomas; Pearson, Thomas C.

    2016-01-01

    This paper examines the case of Starbucks’ UK branch, which became subject to massive public criticism over alleged tax avoidance. Despite Starbucks arguing that its transfer pricing practices were in full compliance with regulatory requirements, public pressure for higher corporate tax payments...... led Starbucks to increase its UK tax payment on transfer pricing income beyond regulatory requirements. This case study suggests that MNE tax behavior on international transfer pricing is not strictly a matter of compliance with formal tax regulation. We demonstrate the way an MNE attempts to re...

  8. 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

  9. 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.

  10. Conflict Avoidance by Descent Behind the Intruder

    Directory of Open Access Journals (Sweden)

    Tone Magister

    2004-03-01

    Full Text Available The paramount priorities for safe implementation of a singlepilot manned cockpit concept and the futuristic concept of asingle pilot acting as a supervisor for a fully automated aircraftflying on incessantly self-optimised trajectories are eliminationsof the risk of mid-air collisions and of conflicts resulting fromthe lack of safe airborne separations. Avoidance procedureswith initiation of descent behind the intruder for conflict resolutionbetween a pair of aircraft where one of them is in the vicinityof the top of its descent represents merely one little piece ofthis giant puzzle.

  11. Contact Dermatitis, Patch Testing, and Allergen Avoidance.

    Science.gov (United States)

    Burkemper, Nicole M

    2015-01-01

    In patients presenting with a complaint of rash, contact dermatitis is often the underlying diagnosis making it an entity with which health care providers should be familiar. Contact dermatitis can be divided into irritant contact dermatitis and allergic contact dermatitis. In a patient suspected of having allergic contact dermatitis, patch testing can be done to identify specific allergens. Education focused on allergen avoidance and safe products is an integral part of treatment for the contact dermatitis patient. Knowledge of the most common allergens is helpful for clinicians to be able to provide this education.

  12. 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.

  13. 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

  14. 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.

  15. Long-term avoidance memory formation is associated with a transient increase in mushroom body synaptic complexes in leaf-cutting ants

    Directory of Open Access Journals (Sweden)

    Agustina eFalibene

    2015-04-01

    Full Text Available Long-term behavioral changes related to learning and experience have been shown to be associated with structural remodeling in the brain. Leaf-cutting ants learn to avoid previously preferred plants after they have proved harmful for their symbiotic fungus, a process that involves long-term olfactory memory. We studied the dynamics of brain microarchitectural changes after long-term olfactory memory formation following avoidance learning in Acromyrmex ambiguus. After performing experiments to control for possible neuronal changes related to age and body size, we quantified synaptic complexes (microglomeruli, MG in olfactory regions of the mushroom bodies (MB at different times after learning. Long-term avoidance memory formation was associated with a transient change in MG densities. Two days after learning, MG density was higher than before learning. At days 4 and 15 after learning — when ants still showed plant avoidance — MG densities had decreased to the initial state. The structural reorganization of MG triggered by long-term avoidance memory formation clearly differed from changes promoted by pure exposure to and collection of novel plants with distinct odors. Sensory exposure by the simultaneous collection of several, instead of one, non-harmful plant species resulted in a decrease in MG densities in the olfactory lip. We hypothesize that while sensory exposure leads to MG pruning in the MB olfactory lip, the formation of long-term avoidance memory involves an initial growth of new MG followed by subsequent pruning.

  16. Internationalizing Student Learning and Development

    Science.gov (United States)

    Roberts, Dennis C.; Komives, Susan R.

    2016-01-01

    Best practices in internationalizing student learning and development require cultural critical analysis before transferring, adapting, hedging, or avoiding existing practices in cross-border applications both in and beyond the classroom.

  17. 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

  18. How to Avoid an Educational Malpractice Suit.

    Science.gov (United States)

    Patterson, Arlene H.

    Increasing demands for professional accountability in education, coupled with a growing tendency in the American public to seek redress through the courts, have given rise to the educational malpractice suit, alleging that students have failed to learn because schools have been negligent in their duty to educate. This chapter provides guidelines…

  19. Underactuated spacecraft formation reconfiguration with collision avoidance

    Science.gov (United States)

    Huang, Xu; Yan, Ye; Zhou, Yang

    2017-02-01

    Underactuated collision-free controllers are proposed in this paper for multiple spacecraft formation reconfiguration in circular orbits with the loss of either the radial or in-track thrust. A nonlinear dynamical model of underactuated formation flying is introduced, which is then linearized about circular orbits for controllability and feasibility analyses on underactuated formation reconfiguration. By using the inherent dynamics coupling of system states, reduced-order sliding mode controllers are then designed for either case to indirectly stabilize the system trajectories to the desired formations. In consideration of the collision-avoidance requirement, the artificial potential function method is then employed to design novel underactuated collision-avoidance maneuvers. Rigorous proof substantiates the capabilities of such maneuvers in preventing collisions even in the absence of radial or in-track thrust. Furthermore, a Lyapunov-based analysis ensures the asymptotic stability of the overall closed-loop system. Numerical simulations are performed in a J2-perturbed environment to verify the validity of the proposed underactuated control schemes for collision-free reconfiguration.

  20. 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.

  1. Honey bees selectively avoid difficult choices.

    Science.gov (United States)

    Perry, Clint J; Barron, Andrew B

    2013-11-19

    Human decision-making strategies are strongly influenced by an awareness of certainty or uncertainty (a form of metacognition) to increase the chances of making a right choice. Humans seek more information and defer choosing when they realize they have insufficient information to make an accurate decision, but whether animals are aware of uncertainty is currently highly contentious. To explore this issue, we examined how honey bees (Apis mellifera) responded to a visual discrimination task that varied in difficulty between trials. Free-flying bees were rewarded for a correct choice, punished for an incorrect choice, or could avoid choosing by exiting the trial (opting out). Bees opted out more often on difficult trials, and opting out improved their proportion of successful trials. Bees could also transfer the concept of opting out to a novel task. Our data show that bees selectively avoid difficult tasks they lack the information to solve. This finding has been considered as evidence that nonhuman animals can assess the certainty of a predicted outcome, and bees' performance was comparable to that of primates in a similar paradigm. We discuss whether these behavioral results prove bees react to uncertainty or whether associative mechanisms can explain such findings. To better frame metacognition as an issue for neurobiological investigation, we propose a neurobiological hypothesis of uncertainty monitoring based on the known circuitry of the honey bee brain.

  2. 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

  3. Cognitive involvement by negative modulation of histamine H2 receptors in passive avoidance task in mice.

    Science.gov (United States)

    Onodera, K; Miyazaki, S; Imaizumi, M

    1998-05-01

    In this study, the intracerebroventricular administration of 4-methylhistamine (3 and 10 micrograms/head), a histamine H2 receptor agonist, shortened the step-through latency in the retention trial using a step-through passive avoidance task in mice. This deteriorating effect of 4-methylhistamine (3 micrograms/head) was clearly antagonized by pretreatment with zolantidine (10 mg/kg, i.p.), a histamine H2 receptor antagonist, 20 min before an acquisition trial. Zolantidine alone at the dose tested had no effect. Thus, it is likely that activation of histamine H2 receptors has a deteriorating effect on avoidance learning in mice. The present results indicate the cognitive involvement by negative modulation of histamine H2 receptors in passive avoidance task in mice.

  4. 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

  5. Avoidable cancers in the Nordic countries. Radiation

    DEFF Research Database (Denmark)

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

    1997-01-01

    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......, it was estimated that the exposure of the Nordic populations to natural sources of ionizing radiation other than radon and to medical sources will each give rise to an annual total of 2120 cancers at various sites. For all types of ionizing radiation, the annual total will be 4420 cancer cases, or 3.9% of all...... 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...

  6. DENIS Galaxies in the Zone of Avoidance

    CERN Document Server

    Schröder, A; Mamon, G A; Ruphy, S; Paris-Meudon, Obs.

    1997-01-01

    We investigated the potential of using DENIS for studies of galaxies behind the obscuration layer of our Milky Way, and mapping the Galactic extinction. As a pilot study, we examined DENIS I-, J-, and K-band images of heavily obscured galaxies from a deep optical (B_J-band) galaxy survey in the Zone of Avoidance. We tried to uncover additional galaxies at latitudes where the Milky Way remains fully opaque, i.e. we conducted a `blind' search at |b| 4-5 mag. Furthermore, we determined the I, J and K magnitudes of galaxies in the low-latitude, nearby, rich cluster Abell 3627 and compared the resulting colour-colour diagram with that of an unobscured cluster.

  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. 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.

  9. 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.

  10. 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.

  11. Pregnant Women Should Avoid Zika-Hit Texas Town: CDC

    Science.gov (United States)

    ... page: https://medlineplus.gov/news/fullstory_162573.html Pregnant Women Should Avoid Zika-Hit Texas Town: CDC ... 15, 2016 THURSDAY, Dec. 15, 2016 (HealthDay News) -- Pregnant women should avoid traveling to a south Texas ...

  12. 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 are...

  13. Genome-Wide Association Analyses Point to Candidate Genes for Electric Shock Avoidance in Drosophila melanogaster.

    Science.gov (United States)

    Appel, Mirjam; Scholz, Claus-Jürgen; Müller, Tobias; Dittrich, Marcus; König, Christian; Bockstaller, Marie; Oguz, Tuba; Khalili, Afshin; Antwi-Adjei, Emmanuel; Schauer, Tamas; Margulies, Carla; Tanimoto, Hiromu; Yarali, Ayse

    2015-01-01

    Electric shock is a common stimulus for nociception-research and the most widely used reinforcement in aversive associative learning experiments. Yet, nothing is known about the mechanisms it recruits at the periphery. To help fill this gap, we undertook a genome-wide association analysis using 38 inbred Drosophila melanogaster strains, which avoided shock to varying extents. We identified 514 genes whose expression levels and/ or sequences co-varied with shock avoidance scores. We independently scrutinized 14 of these genes using mutants, validating the effect of 7 of them on shock avoidance. This emphasizes the value of our candidate gene list as a guide for follow-up research. In addition, by integrating our association results with external protein-protein interaction data we obtained a shock avoidance-associated network of 38 genes. Both this network and the original candidate list contained a substantial number of genes that affect mechanosensory bristles, which are hair-like organs distributed across the fly's body. These results may point to a potential role for mechanosensory bristles in shock sensation. Thus, we not only provide a first list of candidate genes for shock avoidance, but also point to an interesting new hypothesis on nociceptive mechanisms.

  14. The spread of fear: symbolic generalization mediates graded threat-avoidance in specific phobia.

    Science.gov (United States)

    Dymond, Simon; Schlund, Michael W; Roche, Bryan; Whelan, Robert

    2014-02-01

    Overgeneralization of fear and threat-avoidance represents a formidable barrier to successful clinical treatment of anxiety disorders. While stimulus generalization along quantifiable physical dimensions has been studied extensively, less consideration has been given to symbolic generalization, in which stimuli are indirectly and arbitrarily related. The present study examined whether the magnitude and extent of symbolic generalization of threat-avoidance and threat-beliefs differed between spider-phobic and nonphobic individuals. Initially, participants learned two sets of stimulus equivalence relations (A1 = B1 = C1; A2 = B2 = C2). Next, one cue (B1) was established as a conditioned stimulus (CS + ; threat) that signalled onset of spider images and prompted avoidance, and another cue (B2) was established as a CS- (safety cue) that signalled the absence of such images. Subsequent testing showed that phobics compared to nonphobics exhibited greater symbolic generalization of threat-avoidance to threat cues A1 and C1 (indirect CS+ threat cues related via symmetry and equivalence, respectively), while all individuals showed nonavoidance to indirect safety cues A2 and C2. The enhanced symbolic generalization of threat-beliefs and avoidance behaviour observed in spider phobics warrants further investigation.

  15. Performance of humans in concurrent avoidance/positive-reinforcement schedules

    OpenAIRE

    Ruddle, H. V.; Bradshaw, C M; Szabadi, E; Foster, T M

    1982-01-01

    Performance maintained under concurrent schedules consisting of a variable-interval avoidance component and a variable-interval positive-reinforcement component was studied in three human subjects using points exchangeable for money as the reinforcer. The rate of responding in the avoidance component increased, and the rate of responding in the positive-reinforcement component declined, as a function of the frequency of point-losses avoided in the avoidance component. The performance of all t...

  16. 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.

  17. Neuroimaging the temporal dynamics of human avoidance to sustained threat.

    Science.gov (United States)

    Schlund, Michael W; Hudgins, Caleb D; Magee, Sandy; Dymond, Simon

    2013-11-15

    Many forms of human psychopathology are characterized by sustained negative emotional responses to threat and chronic behavioral avoidance, implicating avoidance as a potential transdiagnostic factor. Evidence from both nonhuman neurophysiological and human neuroimaging studies suggests a distributed frontal-limbic-striatal brain network supports avoidance. However, our understanding of the temporal dynamics of the network to sustained threat that prompts sustained avoidance is limited. To address this issue, 17 adults were given extensive training on a modified free-operant avoidance task in which button pressing avoided money loss during a sustained threat period. Subsequently, subjects underwent functional magnetic resonance imaging while completing the avoidance task. In our regions of interest, we observed phasic, rather than sustained, activation during sustained threat in dorsolateral and inferior frontal regions, anterior and dorsal cingulate, ventral striatum and regions associated with emotion, including the amygdala, insula, substantia nigra and bed nucleus of the stria terminalis complex. Moreover, trait levels of experiential avoidance were negatively correlated with insula, hippocampal and amygdala activation. These findings suggest knowledge that one can consistently avoid aversive outcomes is not associated with decreased threat-related responses and that individuals with greater experiential avoidance exhibit reduced reactivity to initial threat. Implications for understanding brain mechanisms supporting human avoidance and psychological theories of avoidance are discussed.

  18. 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

  19. 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...

  20. 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

  1. 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:...

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. 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...

  7. 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....

  8. 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

  9. 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... by a Grantee? Construction § 75.611 Avoidance of flood hazards. In planning the construction, a...) Evaluate flood hazards in connection with the construction; and (b) As far as practicable, avoid...

  10. 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...

  11. 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…

  12. 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.

  13. Approach and avoidance motivation in eating disorders.

    Science.gov (United States)

    Harrison, Amy; Treasure, Janet; Smillie, Luke D

    2011-08-15

    It has been proposed that approach and avoidance processes may be critically involved in the development and maintenance of eating disorders (EDs), including anorexia nervosa (AN) and bulimia nervosa (BN). The Behavioural Inhibition System and Behavioural Activation System Scales (BIS/BAS) and Appetitive Motivation Scale (AMS) questionnaires were administered to 286 participants: 91 healthy controls (HCs), 121 participants with a current ED, either AN (restrictive and binge purge subtypes), or BN and 74 participants recovered from an ED. Individuals with EDs had higher levels of sensitivity to punishment and lower levels of reward reactivity than controls. Individuals in recovery from an ED scored the same as those in the acute group, with the exception of BAS fun seeking, for which they scored significantly higher than those with restricting AN. Discriminant analysis revealed that HCs were maximally separated from those in the acute and recovered ED groups along a dimension reflecting high punishment sensitivity and low reward sensitivity. Classification analysis demonstrated that ED and HC group membership was predicted from reward and punishment sensitivity measures; however recovered participants tended to be misclassified as ED. This study suggests high punishment sensitivity and low reward reactivity/sensitivity might form a personality cluster associated with the risk of developing an ED.

  14. Management of Sigmoid Volvulus Avoiding Sigmoid Resection

    Science.gov (United States)

    Katsikogiannis, Nikolaos; Machairiotis, Nikolaos; Zarogoulidis, Paul; Sarika, Eirini; Stylianaki, Aikaterini; Zisoglou, Maria; Zervas, Vasilis; Bareka, Metaxia; Christofis, Christos; Iordanidis, Alkis

    2012-01-01

    Acute sigmoid volvulus is typically caused by an excessively mobile and redundant segment of colon with a stretched mesenteric pedicle. When this segment twists on its pedicle, the result can be obstruction, ischemia and perforation. A healthy, 18-year-old Caucasian woman presented to the emergency department complaining of cramping abdominal pain, distention, constipation and obstipation for the last 72 h, accompanied by nausea, vomiting and abdominal tenderness. The patient had tympanitic percussion tones and no bowel sounds. She was diagnosed with acute sigmoid volvulus. Although urgent resective surgery seems to be the appropriate treatment for those who present with acute abdominal pain, intestinal perforation or ischemic necrosis of the intestinal mucosa, the first therapeutic choice for clinically stable patients in good general condition is considered, by many institutions, to be endoscopic decompression. Controversy exists on the decision of the time, the type of definitive treatment, the strategy and the most appropriate surgical technique, especially for teenagers for whom sigmoid resection can be avoided. PMID:22754489

  15. Management of Sigmoid Volvulus Avoiding Sigmoid Resection

    Directory of Open Access Journals (Sweden)

    Nikolaos Katsikogiannis

    2012-05-01

    Full Text Available Acute sigmoid volvulus is typically caused by an excessively mobile and redundant segment of colon with a stretched mesenteric pedicle. When this segment twists on its pedicle, the result can be obstruction, ischemia and perforation. A healthy, 18-year-old Caucasian woman presented to the emergency department complaining of cramping abdominal pain, distention, constipation and obstipation for the last 72 h, accompanied by nausea, vomiting and abdominal tenderness. The patient had tympanitic percussion tones and no bowel sounds. She was diagnosed with acute sigmoid volvulus. Although urgent resective surgery seems to be the appropriate treatment for those who present with acute abdominal pain, intestinal perforation or ischemic necrosis of the intestinal mucosa, the first therapeutic choice for clinically stable patients in good general condition is considered, by many institutions, to be endoscopic decompression. Controversy exists on the decision of the time, the type of definitive treatment, the strategy and the most appropriate surgical technique, especially for teenagers for whom sigmoid resection can be avoided.

  16. 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...

  17. The amygdala: securing pleasure and avoiding pain

    Science.gov (United States)

    Fernando, Anushka B. P.; Murray, Jennifer E.; Milton, Amy L.

    2013-01-01

    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. PMID:24367307

  18. 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.

  19. Aerial vehicles collision avoidance using monocular vision

    Science.gov (United States)

    Balashov, Oleg; Muraviev, Vadim; Strotov, Valery

    2016-10-01

    In this paper image-based collision avoidance algorithm that provides detection of nearby aircraft and distance estimation is presented. The approach requires a vision system with a single moving camera and additional information about carrier's speed and orientation from onboard sensors. The main idea is to create a multi-step approach based on a preliminary detection, regions of interest (ROI) selection, contour segmentation, object matching and localization. The proposed algorithm is able to detect small targets but unlike many other approaches is designed to work with large-scale objects as well. To localize aerial vehicle position the system of equations relating object coordinates in space and observed image is solved. The system solution gives the current position and speed of the detected object in space. Using this information distance and time to collision can be estimated. Experimental research on real video sequences and modeled data is performed. Video database contained different types of aerial vehicles: aircrafts, helicopters, and UAVs. The presented algorithm is able to detect aerial vehicles from several kilometers under regular daylight conditions.

  20. Velocity of chloroplast avoidance movement is fluence rate dependent.

    Science.gov (United States)

    Kagawa, Takatoshi; Wada, Masamitsu

    2004-06-01

    In Arabidopsis leaves, chloroplast movement is fluence rate dependent. At optimal, lower light fluences, chloroplasts accumulate at the cell surface to maximize photosynthetic potential. Under high fluence rates, chloroplasts avoid incident light to escape photodamage. In this paper, we examine the phenomenon of chloroplast avoidance movement in greater detail and demonstrate a proportional relationship between fluence rate and the velocity of chloroplast avoidance. In addition we show that the amount of light-activated phototropin2, the photoreceptor for the avoidance response, likely plays a role in this phenomenon, as heterozygous mutant plants show a reduced avoidance velocity compared to that of homozygous wild type plants.

  1. Education and smoking: were Vietnam war draft avoiders also more likely to avoid smoking?

    Science.gov (United States)

    Grimard, Franque; Parent, Daniel

    2007-09-01

    We use the Vietnam war draft avoidance behavior documented by Card and Lemieux [Card, D., Lemieux, T., May 2001. Did draft avoidance raise college attendance during the Vietnam war? American Economic Review 91 (2), 97-102] as a quasi experiment to infer causation from education to smoking and find strong evidence that education, whether measured in years of completed schooling or in educational attainment categories, reduces the probability of smoking at the time of the interview, more particularly the probability of smoking regularly. However, while we find that more education substantially increases the probability of never smoking, our instrumental procedure yields imprecise estimates of the effect of education on smoking cessation. Potential mechanisms linking education and smoking are also explored.

  2. Faecal avoidance and selective foraging: do wild mice have the luxury to avoid faeces?

    Science.gov (United States)

    Walsh, Patrick T; McCreless, Erin; Pedersen, Amy B

    2013-09-01

    Host-parasite interactions are a key determinant of the population dynamics of wild animals, and behaviours that reduce parasite transmission and infection may be important for improving host fitness. While antiparasite behaviours have been demonstrated in laboratory animals and domesticated ungulates, whether these behaviours operate in the wild is poorly understood. Therefore, examining antiparasite behaviours in natural populations is crucial for understanding their ecological significance. In this study, we examined whether two wild rodents (white-footed mice, Peromyscus leucopus, and deer mice, Peromyscus maniculatus), selectively foraged away from conspecific faeces or avoided faeces altogether, and whether faecal gastrointestinal parasite status affected their behaviour. We also tested whether wild mice, when nesting, avoided using material that had previously been used by healthy or parasite-infected conspecifics. Our results, in contrast to laboratory mouse studies, suggest that wild mice do not demonstrate faecal avoidance, selective foraging or selective use of nesting material; they preferred being near faeces and did not differentiate between faeces from parasitized and uninfected conspecifics. Behavioural avoidance to reduce parasite infection may still represent an important strategy; however, mice in our study population appeared to favour the opportunity to feed and nest over the risks of coming into contact with faecal-transmitted parasites. Furthermore, the presence of conspecific faeces may actually provide a positive cue of a good foraging or nesting location. Ultimately, balancing the trade-off of performing antiparasite behaviours to reduce infection with missing an important feeding or nesting opportunity may be very different for animals in the wild facing complex and stochastic environments.

  3. Clinical Practice of Steroid Avoidance in Pediatric Kidney Transplantation.

    Science.gov (United States)

    Nehus, E; Liu, C; Hooper, D K; Macaluso, M; Kim, M-O

    2015-08-01

    Steroid-avoidance protocols have recently gained popularity in pediatric kidney transplantation. We investigated the clinical practice of steroid avoidance among 9494 kidney transplant recipients at 124 transplant centers between 2000 and 2012 in the Organ Procurement and Transplantation Network database. The practice of steroid avoidance increased during the study period and demonstrated significant variability among transplant centers. From 2008 to 2012, 39% of transplant centers used steroid avoidance in avoidance in 10-40% of transplant recipients, and 40% of transplant centers used steroid avoidance in >40% of discharged patients. Children receiving steroid avoidance more frequently received induction with lymphocyte-depleting agents. Repeat kidney transplants were the least likely to receive steroid avoidance. Children who received a deceased donor kidney, underwent pretransplant dialysis, were highly sensitized, or had glomerular kidney disease or delayed graft function were also less likely to receive steroid avoidance. The variation in practice between centers remained highly significant (p avoidance among transplant centers remain unexplained and may reflect uncertainty about the safety and efficacy of steroid-avoidance protocols.

  4. AVOIDING STEREOTYPING AND ENHANCING INTERCULTURAL UNDERSTANDING

    Directory of Open Access Journals (Sweden)

    Alistair Welsh

    2011-01-01

    Full Text Available necdotally, language learners often struggle to acquire in­tercultural understanding. Teaching intercultural understanding presents significant challenges for language teachers. This article offers some in-sights into language learners' intercultural understanding and strategies to help enhance intercultural understanding that seek to promote analyti­cal and critical thinking. The aim is to build on the principles of the emerging pedagogy of Intercultural Language Learning (1cLL. IcLL suggests there is a 'third place', where cultures overlap. IcLL acknowl­edges the importance of identifying with the 'other', whilst not denying the 'self'. Intercultural competence requires sensitivity to difference, an ability to identify with others and to critically reflect on one's own cul­tural background.

  5. Body checking and avoidance in ethnically diverse female college students.

    Science.gov (United States)

    White, Emily K; Warren, Cortney S

    2013-09-01

    Although body checking and avoidance behaviors are common in women with eating disorders, minimal research has examined the nature or correlates of these behaviors in ethnically diverse female college students without eating disorders. Self-identified European American (n=268), Asian American (n=163), Latina (n=146), and African American (n=73) women completed self-report measures of body checking and avoidance, thin-ideal internalization, eating pathology, and clinical impairment. Results indicated that European and Asian American women reported significantly more body checking and avoidance than African American and Latina women. Generally, correlates of body checking and avoidance were consistent across ethnic groups: Regression analyses indicated that type of ethnicity predicted body checking and avoidance; and ethnicity, body checking, and body avoidance predicted eating pathology and clinical impairment. These associations suggest that body checking and avoidance are not benign behaviors in diverse nonclinical women.

  6. Geoengineering to Avoid Overshoot: An Uncertainty Analysis

    Science.gov (United States)

    Tanaka, K.

    2009-04-01

    Geoengineering (or climate engineering) using stratospheric sulfur injections (Crutzen, 2006) has been called for research in case of an urgent need for stopping global warming when other mitigation efforts were exhausted. Although there are a number of concerns over this idea (e.g. Robock, 2008), it is still useful to consider geoengineering as a possible method to limit warming caused by overshoot. Overshoot is a feature accompanied by low stabilizations scenarios aiming for a stringent target (Rao et al., 2008) in which total radiative forcing temporarily exceeds the target before reaching there. Scenarios achieving a 50% emission reduction by 2050 produces overshoot. Overshoot could cause sustained warming for decades due to the inertia of the climate system. If stratospheric sulfur injections were to be used as a "last resort" to avoid overshoot, what would be the suitable start-year and injection profile of such an intervention? Wigley (2006) examined climate response to combined mitigation/geoengineering scenarios with the intent to avert overshoot. Wigley's analysis demonstrated a basic potential of such a combined mitigation/geoengineering approach to avoid temperature overshoot - however it considered only simplistic sulfur injection profiles (all started in 2010), just one mitigation scenario, and did not examine the sensitivity of the climate response to any underlying uncertainties. This study builds upon Wigley's premise of the combined mitigation/geoengineering approach and brings associated uncertainty into the analysis. First, this study addresses the question as to how much geoengineering intervention would be needed to avoid overshoot by considering associated uncertainty? Then, would a geoengineering intervention of such a magnitude including uncertainty be permissible in considering all the other side effects? This study begins from the supposition that geoengineering could be employed to cap warming at 2.0°C since preindustrial. A few

  7. The effects of environmental enrichment and age-related differences on inhibitory avoidance in zebrafish (Danio rerio Hamilton)

    NARCIS (Netherlands)

    Manuel, R.; Gorissen, M.; Stokkermans, M.; Zethof, J.; Ebbesson, L.O.E.; Vis, van de J.W.; Flik, G.; Bos, van den R.

    2015-01-01

    The inhibitory avoidance paradigm allows the study of mechanisms underlying learning and memory formation in zebrafish (Danio rerio Hamilton). For zebrafish, the physiology and behavior associated with this paradigm are as yet poorly understood. We therefore assessed the effects of environmental enr

  8. 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…

  9. E-learning

    Directory of Open Access Journals (Sweden)

    Safwan AL SALAIMEH

    2006-07-01

    Full Text Available E-learning means learning via electronic means and is therefore an all-embracing term covering learning via an electronic device. The "expectations" and "realities" for each of the delivery mechanisms within the electronic arena vary greatly for not just the learners themselves, but also the site providers [1]. Because of this, each of these learning systems has vastly different design principles, which is not always understood by those unfamiliar with technology. What is appropriate for a CD-ROM off-line system is generally inappropriate for an on-line internet system. So when designing an e-learning system it is important to understand how the information is to be accessed by the learner. This paper will identify and suggest some ways to avoid e-learning's pitfalls and reap its rewards.

  10. 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.

  11. 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)

  12. Chlorpheniramine facilitates inhibitory avoidance in teleosts submitted to telencephalic ablation

    Directory of Open Access Journals (Sweden)

    F.R. Faganello

    2008-05-01

    Full Text Available The present study investigated the involvement of H(1 histaminegic receptor on the acquisition of inhibitory avoidance in Carassius auratus submitted to telencephalic ablation. The fish were submitted to telencephalic ablation 5 days before the experiment. The inhibitory avoidance procedure included 1 day for habituation, 3 days for training composed of 3 trials each (1st day: T1, T2, T3; 2nd day: 2T1, 2T2, 2T3; 3rd day: 3T1, 3T2, 3T3 and 1 day for test. On training days, the fish were placed in a white compartment, after 30 s the door was opened. When the fish crossed to a black compartment, a weight was dropped (aversive stimuli. Immediately after the third trial, on training days, the fish received, intraperitoneally, one of the pharmacological treatments (saline (N = 20, 8 (N = 12 or 16 (N = 13 µg/g chlorpheniramine, CPA. On the test day, the time to cross to the black compartment was determined. The latency of the saline group increased significantly only on the 3rd trial of the 2nd training day (mean ± SEM, T1 (50.40 ± 11.69, 2T3 (226.05 ± 25.01; ANOVA: P = 0.0249, Dunn test: P < 0.05. The group that received 8 µg/g CPA showed increased latencies from the 2nd training day until the test day (T1 (53.08 ± 17.17, 2T2 (197.75 ± 35.02, test (220.08 ± 30.98; ANOVA: P = 0.0022, Dunn test: P < 0.05. These results indicate that CPA had a facilitating effect on memory. We suggest that the fish submitted to telencephalic ablation were able to learn due to the local circuits of the mesencephalon and/or diencephalon and that CPA interferes in these circuits, probably due an anxiolytic-like effect.

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. Avoidant symptoms in PTSD predict fear circuit activation during multimodal fear extinction.

    Science.gov (United States)

    Sripada, Rebecca K; Garfinkel, Sarah N; Liberzon, Israel

    2013-01-01

    Convergent evidence suggests that individuals with posttraumatic stress disorder (PTSD) exhibit exaggerated avoidance behaviors as well as abnormalities in Pavlonian fear conditioning. However, the link between the two features of this disorder is not well understood. In order to probe the brain basis of aberrant extinction learning in PTSD, we administered a multimodal classical fear conditioning/extinction paradigm that incorporated affectively relevant information from two sensory channels (visual and tactile) while participants underwent fMRI scanning. The sample consisted of fifteen OEF/OIF veterans with PTSD. In response to conditioned cues and contextual information, greater avoidance symptomatology was associated with greater activation in amygdala, hippocampus, vmPFC, dmPFC, and insula, during both fear acquisition and fear extinction. Heightened responses to previously conditioned stimuli in individuals with more severe PTSD could indicate a deficiency in safety learning, consistent with PTSD symptomatology. The close link between avoidance symptoms and fear circuit activation suggests that this symptom cluster may be a key component of fear extinction deficits in PTSD and/or may be particularly amenable to change through extinction-based therapies.

  1. 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.

  2. Children's Avoidance of Interrupting Others' Activities in Requesting Help: Cultural Aspects of Considerateness.

    Science.gov (United States)

    Ruvalcaba, Omar; Rogoff, Barbara; López, Angélica; Correa-Chávez, Maricela; Gutiérrez, Kris

    2015-01-01

    To be able to collaborate skillfully, people need to coordinate well with others, taking into account how their actions fit with those of their partners. This is a key aspect of an approach to learning called Learning by Observing and Pitching In, hypothesized to be common in many Indigenous-heritage communities of the Americas. This chapter considers cultural values that emphasize considerateness and awareness of how one's actions impact others such as the Mexican cultural value of respeto and cultural differences in children's efforts to avoid interrupting others' activity. US Mexican-heritage children showed more evidence of avoiding interrupting the ongoing activity of an adult when they requested help, compared with European American children from families with extensive schooling experience. Most of the Mexican-heritage children's requests for help that gave evidence of avoiding interruption were made nonverbally, which may facilitate unobtrusive requests. There were no significant differences among children from two US Mexican-heritage backgrounds varying in experience with Western schooling and likely experience with Indigenous-American practices, suggesting that the Mexican cultural value of respeto and associated considerateness is widespread even among US Mexican-heritage families with extensive experience with Western schooling and life in the United States.

  3. 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.

  4. 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.

  5. 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).

  6. A dynamical system approach to realtime obstacle avoidance

    OpenAIRE

    Khansari-Zadeh, S. M.; Billard, Aude

    2012-01-01

    This paper presents a novel approach to real-time obstacle avoidance based on dynamical systems (DS) that ensures impenetrability of multiple convex shaped objects. The proposed method can be applied to perform obstacle avoidance in Cartesian and Joint spaces and using both autonomous and non-autonomous DS-based controllers. Obstacle avoidance proceeds by modulating the original dynamics of the controller. The modulation is parameterizable and allows to determine a safety margin and to increa...

  7. To approach or to avoid: neurobiological mechanisms in social anxiety

    OpenAIRE

    Peer, Jacobien Marit van

    2009-01-01

    We investigated the role of cortisol (an important stress-hormone) in the regulation of social fear and avoidance behavior in socially anxious individuals, which are characterized by extreme fear and avoidance of social situations. Previous studies in animals and children showed a relation between increased fearfulness and avoidance and elevated cortisol levels, but the causal role of cortisol in these processes is not known. We found that, only in high socially anxious participants, cortisol...

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

    OpenAIRE

    Mentor Gashi; Halil Kukaj

    2016-01-01

    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, l...

  9. WOAH: an obstacle avoidance technique for high speed path following

    Science.gov (United States)

    Tuck, Nat; McGuinness, Michael; Martin, Fred

    2011-01-01

    This paper presents WOAH, a method for real-time mobile robot path following and obstacle avoidance. WOAH provides reactive speed and turn instructions based on obstacle information sensed by a laser range finder. Unlike many previous techniques, this method allows a robot to move quickly past obstacles that are not directly in its path, avoiding slowdowns in path following encountered by previous obstacle avoidance techniques.

  10. 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.

  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. 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…

  13. Passive Avoidance Is Linked to Impaired Fear Extinction in Humans

    Science.gov (United States)

    Cornwell, Brian R.; Overstreet, Cassie; Krimsky, Marissa; Grillon, Christian

    2013-01-01

    Conventional wisdom dictates we must face our fears to conquer them. This idea is embodied in exposure-based treatments for anxiety disorders, where the intent of exposure is to reverse a history of avoidant behavior that is thought to fuel a patient's irrational fears. We tested in humans the relationship between fear and avoidance by combining…

  14. 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…

  15. 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... Television Band Devices § 15.711 Interference avoidance mechanisms. (a) Except as provided in § 15.717... mechanism described in paragraph (b) of this section or spectrum sensing described in paragraph (c) of...

  16. 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)

  17. 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.

  18. Twenty Common Testing Mistakes for EFL Teachers to Avoid

    Science.gov (United States)

    Henning, Grant

    2012-01-01

    To some extent, good testing procedure, like good language use, can be achieved through avoidance of errors. Almost any language-instruction program requires the preparation and administration of tests, and it is only to the extent that certain common testing mistakes have been avoided that such tests can be said to be worthwhile selection,…

  19. 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....

  20. 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....

  1. 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...

  2. 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...

  3. 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...

  4. Conflict: Run! Reduced Stroop interference with avoidance responses

    NARCIS (Netherlands)

    Schouppe, N.; de Houwer, J.; Ridderinkhof, K.R.; Notebaert, W.

    2012-01-01

    Conflict has been hypothesized to be aversive, triggering avoidance behaviour (Botvinick, 2007). To test this hypothesis, a standard Stroop task was modified such that avoiding was part of the response set. More precisely, participants were asked to move a manikin towards or away from Stroop stimuli

  5. 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... (CONTINUED) ADVISORY COMMITTEES ON STANDARDS Organizational Matters § 1912.4 Avoidance of duplication. No... advisory committee established under section 7(b) of the Act....

  6. Scheduled Collision Avoidance in wireless sensor network using Zigbee

    DEFF Research Database (Denmark)

    Dnyaneshwar, Mantri; Prasad, Neeli R.; Prasad, Ramjee

    2014-01-01

    . This paper proposes the Schedule based Collision Avoidance (SCA) algorithm for finding the tradeoff between reliability and energy efficiency by fusion of CSMA/CA and TDMA techniques in Zigbee/ IEEE802.15.4. It uses the multi-path data propagation for collision avoidance and effective utilization...

  7. To approach or to avoid : neurobiological mechanisms in social anxiety

    NARCIS (Netherlands)

    Peer, Jacobien Marit van

    2009-01-01

    We investigated the role of cortisol (an important stress-hormone) in the regulation of social fear and avoidance behavior in socially anxious individuals, which are characterized by extreme fear and avoidance of social situations. Previous studies in animals and children showed a relation between i

  8. 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 A A A What's in this article? Planning ... is the last resort for someone who has asthma. If a flare-up is really out of ...

  9. 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... MANAGEMENT CUSTODY Use of Force and Application of Restraints on Inmates § 552.23 Confrontation avoidance... information about the inmate and the immediate situation. Based on their assessment of that information,...

  10. 40 CFR 141.171 - Criteria for avoiding filtration.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Criteria for avoiding filtration. 141... PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Enhanced Filtration and Disinfection-Systems Serving 10,000 or More People § 141.171 Criteria for avoiding filtration. In addition to...

  11. 40 CFR 141.71 - Criteria for avoiding filtration.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Criteria for avoiding filtration. 141... PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Filtration and Disinfection § 141.71 Criteria for avoiding filtration. A public water system that uses a surface water source must meet all...

  12. Teacher Distress and the Role of Experiential Avoidance

    Science.gov (United States)

    Hinds, Erika; Jones, Laura Backen; Gau, Jeffrey M.; Forrester, Kathleen K.; Biglan, Anthony

    2015-01-01

    Teachers' psychological well-being is important for teachers and students, but teaching is highly stressful, particularly in special education. We examined the role of experiential avoidance (EA) in the well-being of 529 middle and elementary school teachers. EA involves the tendency to avoid thoughts, feelings, and other internal experiences,…

  13. 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

  14. 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.

  15. 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.

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

    Science.gov (United States)

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

    2017-01-01

    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.

  17. Internet addiction symptoms, disordered eating, and body image avoidance.

    Science.gov (United States)

    Rodgers, Rachel F; Melioli, Tiffany; Laconi, Stéphanie; Bui, Eric; Chabrol, Henri

    2013-01-01

    Internet addiction is an increasing concern among young adults. Self-presentational theory posits that the Internet offers a context in which individuals are able to control their image. Little is known about body image and eating concerns among pathological Internet users. The aim of this study was to explore the association between Internet addiction symptoms, body image esteem, body image avoidance, and disordered eating. A sample of 392 French young adults (68 percent women) completed an online questionnaire assessing time spent online, Internet addiction symptoms, disordered eating, and body image avoidance. Fourteen men (11 percent) and 26 women (9.7 percent) reported Internet addiction. Body image avoidance was associated with Internet addiction symptoms among both genders. Controlling for body-mass index, Internet addiction symptoms, and body image avoidance were both significant predictors of disordered eating among women. These findings support the self-presentational theory of Internet addiction and suggest that body image avoidance is an important factor.

  18. 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.

  19. Disasters of endoscopic surgery and how to avoid them: error analysis.

    Science.gov (United States)

    Troidl, H

    1999-08-01

    For every innovation there are two sides to consider. For endoscopic surgery the positive side is more comfort for the patient, and the negative side is new complications, even disasters, such as injuries to organs (e.g., the bowel), vessels, and the common bile duct. These disasters are rare and seldom reported in the scientific world, as at conferences, at symposiums, and in publications. Today there are many methods for testing an innovation (controlled clinical trials, consensus conferences, audits, and confidential inquiries). Reporting "complications," however, does not help to avoid them. We need real methods for avoiding negative failures. The failure analysis is the method of choice in industry. If an airplane crashes, error analysis starts immediately. Humans make errors, and making errors means punishment. Failure analysis means rigorously and objectively investigating a clinical situation to find clinical relevant information for avoiding these negative events in the future. Error analysis has four important steps: (1) What was the clinical situation? (2) What has happened? (3) Most important: Why did it happen? (4) How do we avoid the negative event or disaster in the future. Error analysis has decisive advantages. It is easy to perform; it supplies clinically relevant information to help avoid it; and there is no need for money. It can be done everywhere; and the information is available in a short time. The other side of the coin is that error analysis is of course retrospective, it may not be objective, and most important it will probably have legal consequences. To be more effective in medicine and surgery we must handle our errors using a different approach. According to Sir Karl Popper: "The consituation is that we have to learn from our errors. To cover up failure is therefore the biggest intellectual sin.

  20. 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.

  1. 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…

  2. 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)

  3. Learning How to Learn

    DEFF Research Database (Denmark)

    Lauridsen, Karen M.; Lauridsen, Ole

    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...... 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...... by Constructivist learning theory and current basic knowledge of how the brain learns. The LS concept will thus be placed in a broader learning theoretical context as a strong learning and teaching tool. Participants will be offered the opportunity to have their own LS preferences established before...

  4. 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.

  5. 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.

  6. Avoided-level-crossing statistics in open chaotic billiards.

    Science.gov (United States)

    Poli, Charles; Dietz, Barbara; Legrand, Olivier; Mortessagne, Fabrice; Richter, Achim

    2009-09-01

    We investigate a two-level model with a large number of open decay channels in order to describe avoided level crossing statistics in open chaotic billiards. This model allows us to describe the fundamental changes in the probability distribution of the avoided level crossings compared with the closed case. Explicit expressions are derived for systems with preserved and broken time-reversal symmetry. We find that the decay process induces a modification at small spacings of the probability distribution of the avoided level crossings due to an attraction of the resonances. The theoretical predictions are in complete agreement with the recent experimental results of Dietz [Phys. Rev. E 73, 035201 (2006)].

  7. 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.

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

    OpenAIRE

    Palminteri, S; 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...

  9. 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)

  10. 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.

  11. How You Can Help Your Child Avoid & Address Bullying

    Science.gov (United States)

    ... How You Can Help Your Child Avoid & Address Bullying Page Content Article Body Whether on the school ... other ways. Getting that response usually makes the bullying behavior continue. Your child should try to keep ...

  12. 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...

  13. Avoid Counterfeit Pesticide Products for Dogs and Cats

    Science.gov (United States)

    EPA is aware of counterfeit pet pesticides designed to look like legitimately registered pesticide products. The information on this page is intended to help consumers avoid unregistered pet products.

  14. 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.

  15. 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

  16. Avoided losses on LV networks as a result of microgeneration

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Paulo Moises [Escola Superior Tecnologia Viseu, Instituto Politecnico Viseu, Campus Politecnico Repeses, 3504-510 Viseu (Portugal); Matos, Manuel A. [INESC Porto, Faculdade de Engenharia da Universidade do Porto, Porto (Portugal)

    2009-04-15

    In the scope of the discussions about microgeneration (and microgrids), the avoided electrical losses are often pointed out as an important value to be credited to those entities. Therefore, methods to assess the impact of microgeneration on losses must be developed in order to support the definition of a suitable regulatory framework for the economic integration of microgeneration on distribution networks. This paper presents an analytical method to quantify the value of avoided losses that microgeneration may produce on LV networks. Intervals of expected avoided losses are used to account for the variation of avoided losses due to the number, size and location of microgenerators, as well as for the kind of load distribution on LV networks. (author)

  17. 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.

  18. 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)

  19. Obstacle Avoidance Based-Visual Navigation for Micro Aerial Vehicles

    Directory of Open Access Journals (Sweden)

    Wilbert G. Aguilar

    2017-01-01

    Full Text Available This paper describes an obstacle avoidance system for low-cost Unmanned Aerial Vehicles (UAVs using vision as the principal source of information through the monocular onboard camera. For detecting obstacles, the proposed system compares the image obtained in real time from the UAV with a database of obstacles that must be avoided. In our proposal, we include the feature point detector Speeded Up Robust Features (SURF for fast obstacle detection and a control law to avoid them. Furthermore, our research includes a path recovery algorithm. Our method is attractive for compact MAVs in which other sensors will not be implemented. The system was tested in real time on a Micro Aerial Vehicle (MAV, to detect and avoid obstacles in an unknown controlled environment; we compared our approach with related works.

  20. 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 System...

  1. 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.

  2. 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.

  3. 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

  4. Dynamic Obstacle Avoidance for an Omnidirectional Mobile Robot

    OpenAIRE

    Williams, Robert L.; Jianhua Wu

    2010-01-01

    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 moti...

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

    DEFF Research Database (Denmark)

    Kaplan, Sigal; Prato, Carlo Giacomo

    2012-01-01

    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...... of lower crash severity. These trends suggest that efforts to understand the mechanisms of reactions to different critical events should be made to improve in-vehicle warning systems, promote responsible driving behavior, and design forgiving infrastructures....

  6. Incorporation of Tropical Cyclone Avoidance Into Automated Ship Scheduling

    Science.gov (United States)

    2014-06-01

    TROPICAL CYCLONE AVOIDANCE INTO AUTOMATED SHIP SCHEDULING by Stephen W. Lantz June 2014 Thesis Advisor: Walter DeGrange Co-Advisor: Eva...COVERED Master’s Thesis 4. TITLE AND SUBTITLE INCORPORATION OF TROPICAL CYCLONE AVOIDANCE INTO AUTOMATED SHIP SCHEDULING 5. FUNDING NUMBERS 6... cyclones (TCs) frequently disrupt these plans, requiring diversions and inefficient steaming speeds. We evaluate the impact of adding anticipated TC

  7. Phencyclidine prevents spatial navigation and passive avoidance deficits in ibotenate lesioned rats.

    Science.gov (United States)

    O'Connell, A; Earley, B; Leonard, B E

    1994-09-01

    The potential neuroprotective effects of phencyclidine (5 mg/kg i.p.) were assessed in rats which had been treated with the excitotoxin, ibotenic acid (IBO) (0.015 M) to lesion the nucleus basalis magnocellularis. IBO treated rats showed a significant impairment in 13 of the 25 test trials in the spatial navigation Morris water maze task and deficits in passive avoidance learning. Phencyclidine was found to prevent the IBO-induced impairment in 4 of the 13 test trials in which the IBO Morris maze deficit was observed and also successfully prevented the passive avoidance learning deficits. Neurochemically, IBO was shown to reduce the levels of gamma amino-n-butyric acid (GABA) in the cortex. This effect of IBO on the inhibitory GABAergic system may contribute to the direct toxic effects of IBO which is mediated through excitatory amino acid receptors. Phencyclidine had no effect on the changes in GABA produced by IBO. The effect of phencyclidine treatment on IBO behavioural toxicity observed in this study demonstrates that antagonism of the phencyclidine receptor site on the N-methyl-D-aspartate receptor complex may be partially protective against the excitotoxic damage induced by IBO.

  8. General Anti-Avoidance Rule in Latvian Tax Law

    Directory of Open Access Journals (Sweden)

    Milana Belevica

    2016-03-01

    Full Text Available The tax law systems of the EU Member States differ strongly; one is based on the specific anti – avoidance provisions governed by the general principle of prohibition of abuse stated in court jurisprudence, the basement of the other is a written judicial rule which prohibits the abuse – general anti – avoidance rule. General anti-avoidance rules are needed because of conflicts of laws in the borders of one state as well the conflicts of different state’s jurisprudence. There is no legal definition of tax avoidance in the EU law nevertheless the notion of tax avoidance is firmly connected to the concept of abuse of law – a general principle of EU law which has got its prompt development in the resent tax case law of the Court of Justice of the European Union (CJEU. The UK practice is undoubtedly the positive example of methodologically precise legal ruling in the sphere of complicated abstract issues of abuse in tax law. This paper aims to describe the concept of general anti avoidance rule, comparing theoretical cognitions, regulation in Latvia and UK and also tax case law of the Court of Justice of the European Union.

  9. Chloroplasts can move in any direction to avoid strong light.

    Science.gov (United States)

    Tsuboi, Hidenori; Wada, Masamitsu

    2011-01-01

    Chloroplasts migrate in response to different light intensities. Under weak light, chloroplasts gather at an illuminated area to maximize light absorption and photosynthesis rates (the accumulation response). In contrast, chloroplasts escape from strong light to avoid photodamage (the avoidance response). Photoreceptors involved in these phenomena have been identified in Arabidopsis thaliana and Adiantum capillus-veneris. Chloroplast behavior has been studied in detail during the accumulation response, but not for the avoidance response. Hence, we analyzed the chloroplast avoidance response in detail using dark-adapted Adiantum capillus-veneris gametophyte cells and partial cell irradiation with a microbeam of blue light. Chloroplasts escaped from an irradiated spot. Both duration of this response and the distance of the migrated chloroplasts were proportional to the total fluence irradiated. The speed of movement during the avoidance response was dependent on the fluence rate, but the speed of the accumulation response towards the microbeam from cell periphery was constant irrespective of fluence rate. When a chloroplast was only partially irradiated with a strong microbeam, it moved away towards the non-irradiated region within a few minutes. During this avoidance response two additional microbeam irradiations were applied to different locus of the same chloroplast. Under these conditions the chloroplast changed the moving direction after a lag time of a few minutes without rolling. Taken together, these findings indicate that chloroplasts can move in any direction and never have an intrinsic polarity. Similar phenomenon was observed in chloroplasts of Arabidopsis thaliana palisade cells.

  10. Radar-based collision avoidance for unmanned surface vehicles

    Science.gov (United States)

    Zhuang, Jia-yuan; Zhang, Lei; Zhao, Shi-qi; Cao, Jian; Wang, Bo; Sun, Han-bing

    2016-12-01

    Unmanned surface vehicles (USVs) have become a focus of research because of their extensive applications. To ensure safety and reliability and to perform complex tasks autonomously, USVs are required to possess accurate perception of the environment and effective collision avoidance capabilities. To achieve these, investigation into realtime marine radar target detection and autonomous collision avoidance technologies is required, aiming at solving the problems of noise jamming, uneven brightness, target loss, and blind areas in marine radar images. These technologies should also satisfy the requirements of real-time and reliability related to high navigation speeds of USVs. Therefore, this study developed an embedded collision avoidance system based on the marine radar, investigated a highly real-time target detection method which contains adaptive smoothing algorithm and robust segmentation algorithm, developed a stable and reliable dynamic local environment model to ensure the safety of USV navigation, and constructed a collision avoidance algorithm based on velocity obstacle (V-obstacle) which adjusts the USV's heading and speed in real-time. Sea trials results in multi-obstacle avoidance firstly demonstrate the effectiveness and efficiency of the proposed avoidance system, and then verify its great adaptability and relative stability when a USV sailing in a real and complex marine environment. The obtained results will improve the intelligent level of USV and guarantee the safety of USV independent sailing.

  11. A less stressful animal model: a conditioned avoidance behaviour task for guineapigs.

    Science.gov (United States)

    Agterberg, Martijn J H; van den Broek, Marloes; Philippens, Ingrid H C H M

    2010-07-01

    In the conventional shuttle box, animals are trained to avoid electric foot-shocks. As a consequence of these stress-inducing foot-shocks the animals become anxious and are difficult to train. The aim of the present study was to avoid the stress-inducing foot-shocks and to develop a fast and reliable conditioned avoidance behaviour task for guineapigs. We examined whether narrowband noises at four different sound levels above hearing threshold could be used as conditioned stimulus (CS). The unconditioned stimulus (UCS) was a stream of air, which was used instead of the conventionally used electric foot-shocks. The animals were initially trained with a CS of 78 dB sound pressure level (SPL). In this initial training, guineapigs learned to detect a narrowband noise of 78 dB SPL. Interestingly, during the first additional training session in which three other sound levels were applied, guineapigs did not immediately generalize the learned response at 78 dB SPL to lower sound levels of 58 and 68 dB SPL. However, in this session a noise level of 88 dB SPL led immediately to a high level of responses. The response latency decreased with increasing sound level, from approximately 7 s at 58 dB SPL to approximately 3 s at 88 dB SPL. The escape latency during the UCS was approximately 0.6 s. The present results demonstrate that after reducing the level of stress guineapigs can acquire a response in only a few sessions and furthermore, although the guineapigs were less anxious, training at sound levels of 78 and 88 dB SPL was influenced by an aversive reaction by the guineapig. The results indicate that this aversive reaction of the guineapig is crucial for the training.

  12. Passive avoidance training enhances cell proliferation in 1-day-old chicks.

    Science.gov (United States)

    Dermon, C R; Zikopoulos, B; Panagis, L; Harrison, E; Lancashire, C L; Mileusnic, R; Stewart, M G

    2002-10-01

    One-day-old domestic chicks were injected i.p. with bromodeoxyuridine (BrdU) before training on a one-trial passive avoidance task where the aversive experience was a bead coated with a bitter tasting substance, methyl anthranilate (MeA). Animals were tested 24 h later; those avoiding (if MeA-trained) or pecking if water (W)-trained (which they peck appetitively), along with a group of untrained naïve chicks, were used to determine cell proliferation either 24 h or 9 days post BrdU injection. In all three groups, BrdU positive cells were identified sparsely throughout the forebrain but labelling was pronounced around ventricular zone (VZ) surfaces at both 24 h and 9 days post-BrdU-injection. Double immunolabelling with neuronal specific antibodies, to either NeuN, or beta-tubulin III, confirmed that most BrdU labelled cells appeared to be neurons. Unbiased stereological analysis of labelled cells in selected forebrain areas 24 h post BrdU injection showed a significant MeA-training induced increase in labelled cells in both the dorsal VZ surface bordering the intermediate and medial hyperstriatum ventrale (IMHV) and the tuberculum olfactorium (TO). By 9 days post-BrdU-injection, there was a significantly greater number of BrdU labelled cells in MeA-trained birds within the IMHV, lobus parolfactorius (LPO) and TO. These results demonstrate that avoidance training in 1-day-old chicks has a marked effect on cell proliferation, in the LPO and IMHV, regions of the chick previously identified as a key loci of memory formation, and in a second region (TO), which has olfactory functions, but has not been previously investigated in relation to avoidance learning.

  13. Protein synthesis is not required for acquisition, consolidation, and extinction of high foot-shock active avoidance training.

    Science.gov (United States)

    González-Salinas, Sofía; Medina, Andrea C; Marín-Vignando, Vera; Ruiz-López, Clyo X; Quirarte, Gina L; Prado-Alcalá, Roberto A

    2015-01-01

    Long-term memory of active avoidance in mice is not disturbed by administration of protein synthesis inhibitors (PSIs) when relatively high levels of training are used, whereas a detrimental effect is produced with lower levels of training. PSIs also disrupt extinction of avoidance behaviors in rodents, but it is not clear whether PSIs also affect this form of learning when the behavior to be extinguished was produced by a high level of training. Experiment 1 demonstrated that rats treated with the PSI cycloheximide (CXM) 30 min before training developed normal acquisition after training with either high or low foot-shock stimulation, but that memory consolidation was hindered only after low foot-shock training. Experiment 2 demonstrated that CXM disrupted extinction when administered before the first of a series of extinction sessions when low foot-shock intensity was used during training; in contrast, after training with a higher foot-shock, the PSI treatment only interfered transiently with extinction. These results indicate that acquisition, consolidation, and extinction of active avoidance learning produced by high aversive stimulation are not dependent on protein synthesis and that these processes are governed by mechanisms different from those underlying moderate forms of learning.

  14. 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.

  15. 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

  16. 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.

  17. 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…

  18. 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…

  19. Self-Esteem and Service Learning.

    Science.gov (United States)

    Pereira, Carolyn

    1997-01-01

    Maintains that self-esteem is more than simply "feeling good" about oneself. It derives from having experienced meaningful success. A service learning program can accomplish this and avoid the self-preoccupation and narcissism that occasionally accompany self-esteem efforts. Service learning can replace this with empathy and commitment. (MJP)

  20. 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.

  1. Direct and indirect predictors of social anxiety: The role of anxiety sensitivity, behavioral inhibition, experiential avoidance and self-consciousness.

    Science.gov (United States)

    Panayiotou, Georgia; Karekla, Maria; Panayiotou, Margarita

    2014-11-01

    Using mediated and moderated regression, this study examined the hypothesis that anxiety sensitivity, the tendency to be concerned about anxiety symptoms, and behavioral inhibition, the tendency to withdraw from novel and potentially dangerous stimuli, predict social anxiety indirectly through experiential avoidance as measured by the Acceptance and Action Questionnaire-II and self-consciousness, as measured by the Self-Consciousness Scale. Behavioral inhibition and anxiety sensitivity are operationalized as temperamental traits, while experiential avoidance and self-consciousness are seen as learned emotion regulation strategies. Study 1 included college student groups from Cyprus scoring high and low on social anxiety (N=64 and N=63) as measured by the Social Phobia and Anxiety Inventory. Study 2 examined a random community sample aged 18-65 (N=324) treating variables as continuous and using the Psychiatric Disorders Screening Questionnaire to screen for social anxiety. Results suggest that experiential avoidance, but not self-consciousness mediates the effects of anxiety sensitivity on predicting social anxiety status, but that behavioral inhibition predicts social anxiety directly and not through the proposed mediators. Moderation effects were not supported. Overall, the study finds that social anxiety symptomatology is predicted not only by behavioral inhibition, but also anxiety sensitivity, when individuals take actions to avoid anxious experiences. Modifying such avoidant coping approaches may be more beneficial for psychological treatments than attempts to change long-standing, temperamental personality traits.

  2. A new collision avoidance model for pedestrian dynamics

    Science.gov (United States)

    Wang, Qian-Ling; Chen, Yao; Dong, Hai-Rong; Zhou, Min; Ning, Bin

    2015-03-01

    The pedestrians can only avoid collisions passively under the action of forces during simulations using the social force model, which may lead to unnatural behaviors. This paper proposes an optimization-based model for the avoidance of collisions, where the social repulsive force is removed in favor of a search for the quickest path to destination in the pedestrian’s vision field. In this way, the behaviors of pedestrians are governed by changing their desired walking direction and desired speed. By combining the critical factors of pedestrian movement, such as positions of the exit and obstacles and velocities of the neighbors, the choice of desired velocity has been rendered to a discrete optimization problem. Therefore, it is the self-driven force that leads pedestrians to a free path rather than the repulsive force, which means the pedestrians can actively avoid collisions. The new model is verified by comparing with the fundamental diagram and actual data. The simulation results of individual avoidance trajectories and crowd avoidance behaviors demonstrate the reasonability of the proposed model. Project supported by the National Natural Science Foundation of China (Grant Nos. 61233001 and 61322307) and the Fundamental Research Funds for Central Universities of China (Grant No. 2013JBZ007).

  3. A Hybrid Architecture for Vision-Based Obstacle Avoidance

    Directory of Open Access Journals (Sweden)

    Mehmet Serdar Güzel

    2013-01-01

    Full Text Available This paper proposes a new obstacle avoidance method using a single monocular vision camera as the only sensor which is called as Hybrid Architecture. This architecture integrates a high performance appearance-based obstacle detection method into an optical flow-based navigation system. The hybrid architecture was designed and implemented to run both methods simultaneously and is able to combine the results of each method using a novel arbitration mechanism. The proposed strategy successfully fused two different vision-based obstacle avoidance methods using this arbitration mechanism in order to permit a safer obstacle avoidance system. Accordingly, to establish the adequacy of the design of the obstacle avoidance system, a series of experiments were conducted. The results demonstrate the characteristics of the proposed architecture, and the results prove that its performance is somewhat better than the conventional optical flow-based architecture. Especially, the robot employing Hybrid Architecture avoids lateral obstacles in a more smooth and robust manner than when using the conventional optical flow-based technique.

  4. 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.

  5. Attachment avoidance modulates neural response to masked facial emotion.

    Science.gov (United States)

    Suslow, Thomas; Kugel, Harald; Rauch, Astrid Veronika; Dannlowski, Udo; Bauer, Jochen; Konrad, Carsten; Arolt, Volker; Heindel, Walter; Ohrmann, Patricia

    2009-11-01

    According to recent models of individual differences in attachment organization, a basic dimension of adult attachment is avoidance. Attachment-related avoidance corresponds to tendencies to withdraw from close relationships and to an unwillingness to rely on others. In the formation of attachment orientation during infancy facial emotional interaction plays a central role. There exists an inborn very rapid decoding capacity for facial emotional expression. In this study, functional magnetic resonance imaging was used to examine differences in automatic brain reactivity to facial emotions as a function of attachment avoidance in a sample of 51 healthy adults. Pictures of sad and happy faces (which are approach-related interpersonal signals) were presented masked by neutral faces. The Relationship Scales Questionnaire (RSQ) was used to assess the attachment avoidance. Masked sad faces activated the amygdala, the insula, occipito-temporal areas, and the somatosensory cortices. Independently from trait anxiety, depressivity, and detection performance, attachment avoidance was found to be inversely related to responses of the primary somatosensory cortex (BA 3) to masked sad faces. A low spontaneous responsivity of the primary somatosensory cortex to negative faces could be a correlate of the habitual unwillingness to deal with partners' distress and needs for proximity. The somatosensory cortices are known to be critically involved in the processes of emotional mimicry and simulation which have the potential to increase social affiliation. Our data are consistent with the idea that people who withdraw from close relationships respond spontaneously to a lesser extent to negative interpersonal emotional signals than securely attached individuals.

  6. Attention Bias of Avoidant Individuals to Attachment Emotion Pictures

    Science.gov (United States)

    Liu, Ying; Ding, Yi; Lu, Luluzi; Chen, Xu

    2017-01-01

    How attachment style affects emotion processing is tightly connected with individuals’ attention bias. This experiment explored avoidant individuals’ attentional engagement and attentional disengagement using a cue-target paradigm in fMRI. The experimental group consisted of 17 avoidant participants, while the control group consisted of 16 secure participants; these were identified by the Experiences in Close Relationships inventory and the Relationship Questionnaire. Each reacted to pictures of positive parent-child attachment, negative parent-child attachment, positive romantic attachment, negative romantic attachment, and neutral non-attachment. Behaviorally, avoidant individuals were slower than secure individuals in responding to emotions and their attentional disengagement effect for negative parent-child emotions was stronger than positive ones. fMRI results showed that avoidant compared to secure individuals activated more strongly in the right superior temporal gyrus, middle occipital gyrus, and the left medial frontal gyrus, middle occipital gyrus, supplementary motor area, and cingulate gyrus. They also showed stronger activation in disengaging from positive than negative emotions in the bilateral fusiform and middle occipital gyri. In conclusion, avoidant individuals could detect emotions as effective as secure individuals in attentioal engaging stages. They can disengage from positive emotions with effective cognitive resources and were harder to get rid of negative emotions with insufficient resource. PMID:28128347

  7. Sun avoidance strategies at the Large Millimeter Telescope

    Science.gov (United States)

    Souccar, Kamal; Smith, David R.; Schloerb, F. Peter; Wallace, Gary

    2016-07-01

    The Large Millimeter Telescope observatory is extending its night time operation to the day time. A sun avoidance strategy was therefore implemented in the control system in real-time to avoid excessive heating and damage to the secondary mirror and the prime focus. The LMT uses an "on-the-fly" trajectory generator that receives as input the target location of the telescope and in turn outputs a commanded position to the servo system. The sun avoidance strategy is also implemented "on-the-fly" where it intercepts the input to the trajectory generator and alters that input to avoid the sun. Two sun avoidance strategies were explored. The first strategy uses a potential field approach where the sun is represented as a high-potential obstacle in the telescope's workspace and the target location is represented as a low-potential goal. The potential field is repeatedly calculated as the sun and the telescope move and the telescope follows the induced force by this field. The second strategy is based on path planning using visibility graphs where the sun is represented as a polygonal obstacle and the telescope follows the shortest path from its actual position to the target location via the vertices of the sun's polygon. The visibility graph approach was chosen as the favorable strategy due to the efficiency of its algorithm and the simplicity of its computation.

  8. 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.

  9. 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.

  10. 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.

  11. Quick Guide: Chemistry Service-Learning in Higher Education

    Science.gov (United States)

    Vaughn, Rachel L; Seifer, Sarena; Vye Mihalynuk, Tanis

    2004-01-01

    Service-learning in the chemistry curriculum provides an opportunity for students to learn while contributing to their communities. Examples of chemistry service-learning projects at the post-secondary level include: (1) teaching students about lead poisoning avoidance while assessing and analyzing lead content in the paint of older homes; (2)…

  12. Universum Learning for Multiclass SVM

    OpenAIRE

    Dhar, Sauptik; Ramakrishnan, Naveen; Cherkassky, Vladimir; Shah, Mohak

    2016-01-01

    We introduce Universum learning for multiclass problems and propose a novel formulation for multiclass universum SVM (MU-SVM). We also propose a span bound for MU-SVM that can be used for model selection thereby avoiding resampling. Empirical results demonstrate the effectiveness of MU-SVM and the proposed bound.

  13. Avoiding or restricting defectors in public goods games?

    Science.gov (United States)

    Han, The Anh; Pereira, Luís Moniz; Lenaerts, Tom

    2015-02-06

    When creating a public good, strategies or mechanisms are required to handle defectors. We first show mathematically and numerically that prior agreements with posterior compensations provide a strategic solution that leads to substantial levels of cooperation in the context of public goods games, results that are corroborated by available experimental data. Notwithstanding this success, one cannot, as with other approaches, fully exclude the presence of defectors, raising the question of how they can be dealt with to avoid the demise of the common good. We show that both avoiding creation of the common good, whenever full agreement is not reached, and limiting the benefit that disagreeing defectors can acquire, using costly restriction mechanisms, are relevant choices. Nonetheless, restriction mechanisms are found the more favourable, especially in larger group interactions. Given decreasing restriction costs, introducing restraining measures to cope with public goods free-riding issues is the ultimate advantageous solution for all participants, rather than avoiding its creation.

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

    Directory of Open Access Journals (Sweden)

    Patricia Müller-Moulé

    2016-10-01

    Full Text Available 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.

  15. Cognitive factors in panic disorder, agoraphobic avoidance and agoraphobia.

    Science.gov (United States)

    Berle, David; Starcevic, Vladan; Hannan, Anthony; Milicevic, Denise; Lamplugh, Claire; Fenech, Pauline

    2008-02-01

    There remains a lack of consensus regarding the possibility that especially high levels of panic-related cognitions characterise panic disorder with agoraphobia. We administered the Anxiety Sensitivity Index, the Agoraphobic Cognitions Questionnaire and the Anxious Thoughts and Tendencies Scale as well as measures of agoraphobic avoidance to patients diagnosed with panic disorder with agoraphobia (n=75) and without agoraphobia (n=26). Patients with panic disorder with agoraphobia did not score significantly higher on any of the cognitive variables than did panic disorder patients without agoraphobia. However, most of the cognitive variables showed small to moderate-strength correlations with self-report measures of agoraphobic avoidance. Our findings suggest that anxiety sensitivity, catastrophising of the consequences of panic and a general anxiety-prone cognitive style, although to some extent associated with agoraphobic avoidance, do not discriminate panic disorder with agoraphobia from panic disorder without agoraphobia.

  16. 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

  17. 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.

  18. 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.

  19. Computational Approaches to Consecutive Pattern Avoidance in Permutations

    CERN Document Server

    Nakamura, Brian

    2011-01-01

    In recent years, there has been increasing interest in consecutive pattern avoidance in permutations. In this paper, we introduce two approaches to counting permutations that avoid a set of prescribed patterns consecutively. These algoritms have been implemented in the accompanying Maple package CAV, which can be downloaded from the author's website. As a byproduct of the first algorithm, we have a theorem giving a sufficient condition for when two pattern sets are strongly (consecutively) Wilf-Equivalent. For the implementation of the second algorithm, we define the cluster tail generating function and show that it always satisfies a certain functional equation. We also explain how the CAV package can be used to approximate asymptotic constants for single pattern avoidance.

  20. 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.

  1. 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.

  2. Sense and avoid radar for micro/nano robots

    Science.gov (United States)

    Molchanov, Pavlo A.; Asmolova, Olha

    2014-10-01

    Revolutionary new fly eye radar sensor technologies based on an array of directional antennas is eliminating the need for a mechanical scanning antenna or complicated phase processor. Proposed sense and avoid radar based on fly eye radar technology can be very small, provides continuous surveillance of entire sky (360 degree by azimuth and elevation) and can be applied for separate or swarm of micro/nano UAS or UGS. Monopulse technology increases bearing accuracy several folds and radar can be multi-functional, multi-frequency. Fly eye micro-radars are inexpensive, can be expendable. Prototype of sense and avoid radar with two directional antennas has been designed and bench tested.

  3. Food avoidance in athletes: FODMAP foods on the list.

    Science.gov (United States)

    Lis, Dana; Ahuja, Kiran D K; Stellingwerff, Trent; Kitic, Cecilia M; Fell, James

    2016-09-01

    We surveyed 910 athletes to assess behaviours towards self-selected food/ingredient avoidance to minimize gastrointestinal distress. Fifty-five percent eliminated at least 1 high fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) food/category, with up to 82.6% reporting symptom improvement. In athletes indicating that high FODMAP foods trigger gastrointestinal symptoms, lactose (86.5%) was most frequently eliminated, followed by galactooligosaccharides (23.9%), fructose (23.0%), fructans (6.2%), and polyols (5.4%). Athletes avoid predominantly lactose and to a lesser extent other high FODMAP foods to reduce gastrointestinal distress.

  4. 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...... an 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...

  5. 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...... an 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...

  6. A Hands-Free Obstacle Detection and Avoidance System

    Directory of Open Access Journals (Sweden)

    M. Abdul-Niby

    2015-06-01

    Full Text Available In this paper, we present a low cost hands-free detection and avoidance system designed to provide mobility assistance for visually impaired people. An ultrasonic sensor is attached to the jacket of the user and detects the obstacles in front. The information obtained is transferred to the user through audio messages and also by a vibration. The range of the detection is user-defined. A text-to-speech module is employed for the voice signal. The proposed obstacle avoidance device is cost effective, easy to use and easily upgraded.

  7. 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...

  8. Tax avoidance with cross-border hybrid instruments

    DEFF Research Database (Denmark)

    Johannesen, Niels

    2014-01-01

    The rules demarcating debt and equity for tax purposes differ between countries, hence the possibility that a hybrid financial instrument is treated as equity in one country and debt in another. This may create a scope for tax avoidance by allowing firms that invest in foreign countries to combine...... tax deductible interest expenses in the host country and tax favored dividend income in the home country. In this paper, we first develop a formal model of hybrid instruments and show that, for a given pair of countries, firms in at least one country and sometimes in both can avoid taxes on investment...

  9. 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.

  10. 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.

  11. 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.

  12. Position and Obstacle Avoidance Algorithm in Robot Soccer

    Directory of Open Access Journals (Sweden)

    Awang H. Pratomo

    2010-01-01

    Full Text Available Problem statement: Robot soccer is an attractive domain for researchers and students working in the field of autonomous robots. However developing (coding, testing and debugging robots for such domain is a rather complex task. Approach: This study concentrated on developing position and obstacle avoidance algorithm in robot soccer. This part is responsible for realizing soccer skills such as movement, shoot and goal keeping. The formulation of position and obstacle avoidance was based on mathematical approach. This formula is to make sure that the movement of the robot is valid. Velocity of the robot was calculated to set the speed of the robot. The positioning theory including the coordination of the robot (x,y was used to find the obstacle and avoid it. Results: Some simulations and testing had been carried out to evaluate the usefulness of the proposed algorithms. The functions for shooting, movement and obstacle avoidance had been successfully implemented. Conclusion: The results showed its possibility could be used as strategy algorithms in real robot soccer competition.

  13. Sensorimotor Model of Obstacle Avoidance in Echolocating Bats.

    Directory of Open Access Journals (Sweden)

    Dieter Vanderelst

    2015-10-01

    Full Text Available Bat echolocation is an ability consisting of many subtasks such as navigation, prey detection and object recognition. Understanding the echolocation capabilities of bats comes down to isolating the minimal set of acoustic cues needed to complete each task. For some tasks, the minimal cues have already been identified. However, while a number of possible cues have been suggested, little is known about the minimal cues supporting obstacle avoidance in echolocating bats. In this paper, we propose that the Interaural Intensity Difference (IID and travel time of the first millisecond of the echo train are sufficient cues for obstacle avoidance. We describe a simple control algorithm based on the use of these cues in combination with alternating ear positions modeled after the constant frequency bat Rhinolophus rouxii. Using spatial simulations (2D and 3D, we show that simple phonotaxis can steer a bat clear from obstacles without performing a reconstruction of the 3D layout of the scene. As such, this paper presents the first computationally explicit explanation for obstacle avoidance validated in complex simulated environments. Based on additional simulations modelling the FM bat Phyllostomus discolor, we conjecture that the proposed cues can be exploited by constant frequency (CF bats and frequency modulated (FM bats alike. We hypothesize that using a low level yet robust cue for obstacle avoidance allows bats to comply with the hard real-time constraints of this basic behaviour.

  14. 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.

  15. 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…

  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. Neural Correlates of Attentional Flexibility during Approach and Avoidance Motivation.

    Directory of Open Access Journals (Sweden)

    Rebecca D Calcott

    Full Text Available Dynamic, momentary approach or avoidance motivational states have downstream effects on eventual goal success and overall well being, but there is still uncertainty about how those states affect the proximal neurocognitive processes (e.g., attention that mediate the longer-term effects. Attentional flexibility, or the ability to switch between different attentional foci, is one such neurocognitive process that influences outcomes in the long run. The present study examined how approach and avoidance motivational states affect the neural processes involved in attentional flexibility using fMRI with the aim of determining whether flexibility operates via different neural mechanisms under these different states. Attentional flexibility was operationalized as subjects' ability to switch between global and local stimulus features. In addition to subjects' motivational state, the task context was manipulated by varying the ratio of global to local trials in a block in light of recent findings about the moderating role of context on motivation-related differences in attentional flexibility. The neural processes involved in attentional flexibility differ under approach versus avoidance states. First, differences in the preparatory activity in key brain regions suggested that subjects' preparedness to switch was influenced by motivational state (anterior insula and the interaction between motivation and context (superior temporal gyrus, inferior parietal lobule. Additionally, we observed motivation-related differences the anterior cingulate cortex during switching. These results provide initial evidence that motivation-induced behavioral changes may arise via different mechanisms in approach versus avoidance motivational states.

  18. Neural Correlates of Attentional Flexibility during Approach and Avoidance Motivation.

    Science.gov (United States)

    Calcott, Rebecca D; Berkman, Elliot T

    2015-01-01

    Dynamic, momentary approach or avoidance motivational states have downstream effects on eventual goal success and overall well being, but there is still uncertainty about how those states affect the proximal neurocognitive processes (e.g., attention) that mediate the longer-term effects. Attentional flexibility, or the ability to switch between different attentional foci, is one such neurocognitive process that influences outcomes in the long run. The present study examined how approach and avoidance motivational states affect the neural processes involved in attentional flexibility using fMRI with the aim of determining whether flexibility operates via different neural mechanisms under these different states. Attentional flexibility was operationalized as subjects' ability to switch between global and local stimulus features. In addition to subjects' motivational state, the task context was manipulated by varying the ratio of global to local trials in a block in light of recent findings about the moderating role of context on motivation-related differences in attentional flexibility. The neural processes involved in attentional flexibility differ under approach versus avoidance states. First, differences in the preparatory activity in key brain regions suggested that subjects' preparedness to switch was influenced by motivational state (anterior insula) and the interaction between motivation and context (superior temporal gyrus, inferior parietal lobule). Additionally, we observed motivation-related differences the anterior cingulate cortex during switching. These results provide initial evidence that motivation-induced behavioral changes may arise via different mechanisms in approach versus avoidance motivational states.

  19. Enuresis Control through Fading, Escape, and Avoidance Training.

    Science.gov (United States)

    Hansen, Gordon D.

    1979-01-01

    A twin signal device that provides both escape and avoidance conditioning in enuresis control was documented with case studies of two enuretic children (eight and nine years old). In addition, a technique of fading as an adjunct to the process was utilized with one subject. (Author/SBH)

  20. Differences in risk experience between sensation avoiders and sensation seekers

    NARCIS (Netherlands)

    Heino, A.; van der Molen, H.H.; Wilde, G.J S

    1996-01-01

    The prime purpose of our study was to find out whether the need for stimulation has a systematic influence on perceived risk. While driving on a motorway, 21 male sensation avoiders and 21 male sensation seekers had to follow another car, once at a free following distance chosen by the subject himse

  1. 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

  2. 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

  3. Acquisition, extinction and temporal discrimination in human conditioned avoidance.

    Science.gov (United States)

    Molet, Mikaël; Leconte, Claire; Rosas, Juan M

    2006-09-01

    Two experiments were conducted with the aim of designing a videogame for the study of human conditioned avoidance. Participants had to destroy enemy spaceships with the goal of increasing the score in a counter. Coloured signals might announce the launching of a bomb that could hit participant's spaceship producing a 30 points decrease in participant's score. Three groups of participants were trained in discriminating between a warning signal (W) and a safety signal (S) in Experiment 1. Instrumental group could avoid the loss of points by hiding the spaceship before the offset of W. Participants in the Yoked group received the same treatment received by their instrumental partners, regardless of their behaviour. In the Pavlovian group, W was always followed by the loss of points, regardless of participant's behaviour. Discrimination between W and S was better in the Instrumental groups than in the Yoked and Pavlovian control groups. Experiment 2 found extinction of avoidance when the warning signal was not followed by the bomb. Temporal discrimination was found within the participants that received the instrumental contingency in both experiments, with higher avoidance response towards the end of the warning signal. Temporal discrimination disappeared after extinction in Experiment 2.

  4. 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

  5. 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

  6. Crawling-Onset Age Predicts Visual Cliff Avoidance in Infants.

    Science.gov (United States)

    Richards, John E.; Rader, Nancy

    1981-01-01

    Two experiments tested the effects of crawling-onset age, amount of crawling experience, and testing age on avoidance of the deep side of a visual cliff apparatus by human infants. Crawling-onset age disciminated between infants because crawling during the tactile phase interferes with later visual control of locomotion. (Author/RD)

  7. Helping Teenage Girls Avoid the Female Athlete Triad.

    Science.gov (United States)

    Ilardi, Deb

    2002-01-01

    Describes how school nurses can advocate for adolescent female students and help them avoid the female athlete triad that includes disordered eating, amenorrhea, and osteoporosis. The article focuses on consequences of the triad, how to uncover the symptoms, working to improve public support, and creating a successful program through partnership.…

  8. 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.

  9. Secondary Physical Education Avoidance and Gender: Problems and Antidotes

    Science.gov (United States)

    Ryan, Thomas; Poirier, Yves

    2012-01-01

    Our goal was to locate and evaluate the barriers that impact and cause females to avoid secondary elective physical education courses. We sought to find answers to stop the further decline of female enrolment in secondary physical education by looking into curricula, program and instructional variables. Anecdotal evidence informed this study which…

  10. 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.

  11. Nonconscious effects of power on basic approach and avoidance tendencies

    NARCIS (Netherlands)

    Smith, P.K.; Bargh, J.A.

    2008-01-01

    According to the approach/inhibition theory of power (Keltner, Gruenfeld, & Anderson, 2003), having power should be associated with the approach system, and lacking power with the avoidance system. However, to this point research has focused solely on whetherpowerleads to more action, particularly a

  12. 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

  13. How to avoid perioperative visual loss following prone spinal surgery

    Directory of Open Access Journals (Sweden)

    Nancy E Epstein

    2016-01-01

    Conclusions: The best way to avoid POVL following prone spine surgery is to prevent it. Routine use of an arterial line, intraoperative monitoring, a 3-pin head holder, and elevation of the head 10° from the horizontal should limit the risk of encountering POVL after spinal procedures performed in the prone position.

  14. 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.

  15. 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.

  16. Vaginismus : Heightened Harm Avoidance and Pain Catastrophizing Cognitions

    NARCIS (Netherlands)

    Borg, Charmaine; Peters, Madelon L.; Schultz, Willibrord Weijmar; de Jong, Peter J.

    2012-01-01

    Introduction. Catastrophic appraisal of experienced pain may promote hypervigilance and intense pain, while the personality trait of harm avoidance (HA) might prevent the occurrence of correcting such experiences. Women inflicted with vaginismus may enter a self-perpetuating downward spiral of incre

  17. 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.

  18. 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.

  19. Summary of avoidable cancers in the Nordic countries

    DEFF Research Database (Denmark)

    Olsen, J H; Andersen, A; Dreyer, L

    1997-01-01

    An overview is given of the most important known causes of cancer in the five Nordic countries and the resulting number of cancers that are potentially avoidable. The main causes include active and passive smoking, alcohol consumption, exposure to asbestos and other occupational carcinogens, solar...

  20. How to avoid the high costs of physician turnover.

    Science.gov (United States)

    Berger, J E; Boyle, R L

    1992-01-01

    Physician recruitment is a complex, time consuming and competitive activity that is costly in terms of incurred expenses, administrative and physician time and lost revenue. Judith Berger and Robert Boyle, FACMGA, describe how to develop a well-designed retention and recruitment plan to avoid such costs.

  1. 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.

  2. Implicit evaluation bias induced by approach and avoidance

    NARCIS (Netherlands)

    Woud, M.L.; Becker, E.S.; Rinck, M.

    2008-01-01

    We report a study in which faces with a neutral emotional expression were shown on a computer screen. By means of a joystick, participants pulled half of the faces closer (positive approach movement), and pushed the half away (negative avoidance movement). As a result, an operant evaluative conditio

  3. 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.

  4. 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.

  5. Environmental triggers and avoidance in the management of asthma

    Science.gov (United States)

    Gautier, Clarisse; Charpin, Denis

    2017-01-01

    Identifying asthma triggers forms the basis of environmental secondary prevention. These triggers may be allergenic or nonallergenic. Allergenic triggers include indoor allergens, such as house dust mites (HDMs), molds, pets, cockroaches, and rodents, and outdoor allergens, such as pollens and molds. Clinical observations provide support for the role of HDM exposure as a trigger, although avoidance studies provide conflicting results. Molds and their metabolic products are now considered to be triggers of asthma attacks. Pets, dogs, and especially cats can undoubtedly trigger asthmatic symptoms in sensitized subjects. Avoidance is difficult and rarely adhered to by families. Cockroach allergens contribute to asthma morbidity, and avoidance strategies can lead to clinical benefit. Mouse allergens are mostly found in inner-city dwellings, but their implication in asthma morbidity is debated. In the outdoors, pollens can induce seasonal asthma in sensitized individuals. Avoidance relies on preventing pollens from getting into the house and on minimizing seasonal outdoor exposure. Outdoor molds may lead to severe asthma exacerbations. Nonallergenic triggers include viral infections, active and passive smoking, meteorological changes, occupational exposures, and other triggers that are less commonly involved. Viral infection is the main asthma trigger in children. Active smoking is associated with higher asthma morbidity, and smoking cessation interventions should be personalized. Passive smoking is also a risk factor for asthma exacerbation. The implementation of public smoking bans has led to a reduction in the hospitalization of asthmatic children. Air pollution levels have been linked with asthmatic symptoms, a decrease in lung function, and increased emergency room visits and hospitalizations. Since avoidance is not easy to achieve, clean air policies remain the most effective strategy. Indoor air is also affected by air pollutants, such as cigarette smoke and

  6. 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

  7. 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.

  8. 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...

  9. 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.

  10. 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.

  11. 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.

  12. 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...

  13. 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 recovery from acute, subacute, and chronic low back pain....

  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. 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.

  16. 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.

  17. Ego depletion impairs implicit learning.

    Science.gov (United States)

    Thompson, Kelsey R; Sanchez, Daniel J; Wesley, Abigail H; Reber, Paul J

    2014-01-01

    Implicit skill learning occurs incidentally and without conscious awareness of what is learned. However, the rate and effectiveness of learning may still be affected by decreased availability of central processing resources. Dual-task experiments have generally found impairments in implicit learning, however, these studies have also shown that certain characteristics of the secondary task (e.g., timing) can complicate the interpretation of these results. To avoid this problem, the current experiments used a novel method to impose resource constraints prior to engaging in skill learning. Ego depletion theory states that humans possess a limited store of cognitive resources that, when depleted, results in deficits in self-regulation and cognitive control. In a first experiment, we used a standard ego depletion manipulation prior to performance of the Serial Interception Sequence Learning (SISL) task. Depleted participants exhibited poorer test performance than did non-depleted controls, indicating that reducing available executive resources may adversely affect implicit sequence learning, expression of sequence knowledge, or both. In a second experiment, depletion was administered either prior to or after training. Participants who reported higher levels of depletion before or after training again showed less sequence-specific knowledge on the post-training assessment. However, the results did not allow for clear separation of ego depletion effects on learning versus subsequent sequence-specific performance. These results indicate that performance on an implicitly learned sequence can be impaired by a reduction in executive resources, in spite of learning taking place outside of awareness and without conscious intent.

  18. Environmental triggers and avoidance in the management of asthma

    Directory of Open Access Journals (Sweden)

    Gautier C

    2017-03-01

    Full Text Available Clarisse Gautier,1 Denis Charpin1,2 1Department of Pulmonology and Allergy, North Hospital, 2Faculty of Medicine, Aix-Marseille University, Marseille, France Abstract: Identifying asthma triggers forms the basis of environmental secondary prevention. These triggers may be allergenic or nonallergenic. Allergenic triggers include indoor allergens, such as house dust mites (HDMs, molds, pets, cockroaches, and rodents, and outdoor allergens, such as pollens and molds. Clinical observations provide support for the role of HDM exposure as a trigger, although avoidance studies provide conflicting results. Molds and their metabolic products are now considered to be triggers of asthma attacks. Pets, dogs, and especially cats can undoubtedly trigger asthmatic symptoms in sensitized subjects. Avoidance is difficult and rarely adhered to by families. Cockroach allergens contribute to asthma morbidity, and avoidance strategies can lead to clinical benefit. Mouse allergens are mostly found in inner-city dwellings, but their implication in asthma morbidity is debated. In the outdoors, pollens can induce seasonal asthma in sensitized individuals. Avoidance relies on preventing pollens from getting into the house and on minimizing seasonal outdoor exposure. Outdoor molds may lead to severe asthma exacerbations. Nonallergenic triggers include viral infections, active and passive smoking, meteorological changes, occupational exposures, and other triggers that are less commonly involved. Viral infection is the main asthma trigger in children. Active smoking is associated with higher asthma morbidity, and smoking cessation interventions should be personalized. Passive smoking is also a risk factor for asthma exacerbation. The implementation of public smoking bans has led to a reduction in the hospitalization of asthmatic children. Air pollution levels have been linked with asthmatic symptoms, a decrease in lung function, and increased emergency room visits and

  19. [Beeckman's medical learning by reading].

    Science.gov (United States)

    Honma, Eio

    2008-01-01

    Isaac Beeckman (1588-1637) is a self-learning man. He learned medicine by his reading medical books (contemporary and classic). In this paper I study how Beeckman read and understood them. He did not merely memorize them. But he gave some supplementary explanations to their (he thought) insufficient passages, sometimes criticized them and gave mechanical explanation that was based on atomism with hydrostatics. We can find similar ways of reading in the works of Lucretius and Cardano which young Beeckman read repeatedly. Beeckman learned the way of explaining natural phenomena with atomism from Lucretius' De rerum natura, and the way of explaining mechanics with natural philosophy and of demonstrating the principles of natural philosophy with machines from Cardano's De subtilitate. Beeckman's interactive reading is a good style of self-learning, but to avoid some bad effects of self-learning, he had to talk actually to a good respondent such as young Descartes.

  20. 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.

  1. 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…

  2. 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.

  3. Is it cheating or learning the craft of writing? Using Turnitin to help students avoid plagiarism

    OpenAIRE

    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 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 v...

  4. Effects of histamine and cholinergic systems on memory retention of passive avoidance learning in rats.

    Science.gov (United States)

    Eidi, Maryam; Zarrindast, Mohammad-Reza; Eidi, Akram; Oryan, Shahrbanoo; Parivar, Kazem

    2003-03-28

    In the present study, the effects of the histamine and cholinergic systems on memory retention in adult male rats were investigated. Post-training intracerebroventricular injections were carried out in all the experiments. Cholinoceptor agonist, acetylcholine (1-10 microg/rat) or nicotine (1-10 microg/rat), increased, while a cholinoceptor antagonist, scopolamine (5-20 microg/rat), decreased memory retention. The response to acetylcholine was attenuated by scopolamine. Administration of histamine (5-20 microg/rat) reduced, but the histamine H(1) receptor antagonist, pyrilamine (10-50 microg/rat), and the histamine H(2) receptor antagonist, cimetidine (1-50 microg/rat), increased memory retention in rats. The histamine receptor antagonists attenuated the response to histamine. Histamine reduced the acetylcholine- or nicotine-induced enhancement. The histamine receptor antagonists enhanced the nicotine- or acetylcholine-induced response. Histamine potentiated the inhibitory effect induced by scopolamine. It is concluded that histaminergic and cholinergic systems have opposing effects on memory retention. Also, the histaminergic system elicits an interaction with the cholinergic system in memory retention.

  5. Lung Transplantation in Gaucher Disease: A Learning Lesson in Trying to Avoid Both Scylla and Charybdis.

    Science.gov (United States)

    de Boer, Geertje M; van Dussen, Laura; van den Toorn, Leon M; den Bakker, Michael A; Hoek, Rogier A S; Hesselink, Dennis A; Hollak, Carla E M; van Hal, Peter Th W

    2016-01-01

    Gaucher disease (GD), a lysosomal storage disorder, may result in end-stage lung disease. We report successful bilateral lung transplantation in a 49-year-old woman with GD complicated by severe pulmonary hypertension and fibrotic changes in the lungs. Before receiving the lung transplant, the patient was undergoing both enzyme replacement therapy (imiglucerase) and triple pulmonary hypertension treatment (epoprostenol, bosentan, and sildenafil). She had a history of splenectomy, severe bone disease, and renal involvement, all of which were related to GD and considered as relative contraindications for a lung transplantation. In the literature, lung transplantation has been suggested for severe pulmonary involvement in GD but has been reported only once in a child. To our knowledge, until now, no successful procedure has been reported in adults, and no reports deal with the severe potential posttransplantation complications specifically related to GD.

  6. Hemispheric lateralization of memory stages for discriminated avoidance learning in the chick.

    Science.gov (United States)

    Gibbs, Marie E; Andrew, Richard J; Ng, Kim T

    2003-02-17

    Memory formation following the one trial discriminated bead task in the chick falls into three stages (short-term, intermediate and long-term memory) that are defined by susceptibility to different classes of drugs. The stages show sharply timed offsets of sensitivity and loss at specific times after inhibition. Recall of the memory in the chick shows cyclical changes that differ in period between left and right hemispheres, and is marked by a series of brief windows of enhanced recall that recur with periods of about 16 and 25 min in the left and right hemispheres respectively. The timing of these 'retrieval events' corresponds, to a large extent, with the timing of the memory stages seen in the visual discrimination task. Here we examine the effects of left or right hemisphere injection of the main agents (glutamate, ouabain and anisomycin) that have been used to characterize the three stages of memory. We show that memory in the left hemisphere is largely responsible for performance at test and that processes involved in its consolidation generate the phases of memory.

  7. 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 .

  8. 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.

  9. 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.

  10. Efficient Avoidance of the Penalty Zone in Human Eye Movements

    Science.gov (United States)

    Theeuwes, Jan

    2016-01-01

    People use eye movements extremely effectively to find objects of interest in a cluttered visual scene. Distracting, task-irrelevant attention capturing regions in the visual field should be avoided as they jeopardize the efficiency of search. In the current study, we used eye tracking to determine whether people are able to avoid making saccades to a predetermined visual area associated with a financial penalty, while making fast and accurate saccades towards stimuli placed near the penalty area. We found that in comparison to the same task without a penalty area, the introduction of a penalty area immediately affected eye movement behaviour: the proportion of saccades to the penalty area was immediately reduced. Also, saccadic latencies increased, but quite modestly, and mainly for saccades towards stimuli near the penalty area. We conclude that eye movement behaviour is under efficient cognitive control and thus quite flexible: it can immediately be adapted to changing environmental conditions to improve reward outcome. PMID:27930724

  11. 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 ...

  12. Predicting Avoidance of Skin Damage Feedback among College Students

    Science.gov (United States)

    Dwyer, Laura A.; Shepperd, James A.; Stock, Michelle L.

    2015-01-01

    Background Showing people a personal ultraviolet (UV) photograph depicting skin damage can be an effective method for changing sun protection cognitions and behaviors. Purpose We examined whether people opt not to see their UV photograph if given a choice. We also examined predictors of avoidance of skin damage feedback. Methods College students (N = 257) completed questionnaires, viewed example UV photographs, and received the opportunity to see a UV photograph of their face. Results Over one-third of participants opted not to see their UV photograph. Greater perceived risk of sun damage and having fewer coping resources corresponded with greater avoidance, particularly among participants who reported infrequent sun protection behavior. Conclusion The health benefits of UV photography are realized only if people are willing to view the photograph. Our findings suggest the need for interventions that increase receptivity to viewing one’s UV photograph. PMID:25894276

  13. Obstacle-avoiding robot with IR and PIR motion sensors

    Science.gov (United States)

    Ismail, R.; Omar, Z.; Suaibun, S.

    2016-10-01

    Obstacle avoiding robot was designed, constructed and programmed which may be potentially used for educational and research purposes. The developed robot will move in a particular direction once the infrared (IR) and the PIR passive infrared (PIR) sensors sense a signal while avoiding the obstacles in its path. The robot can also perform desired tasks in unstructured environments without continuous human guidance. The hardware was integrated in one application board as embedded system design. The software was developed using C++ and compiled by Arduino IDE 1.6.5. The main objective of this project is to provide simple guidelines to the polytechnic students and beginners who are interested in this type of research. It is hoped that this robot could benefit students who wish to carry out research on IR and PIR sensors.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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

  19. Real-time obstacle avoidance using harmonic potential functions

    Science.gov (United States)

    Kim, Jin-Oh; Khosla, Pradeep K.

    1992-01-01

    This paper presents a new formulation of the artificial potential approach to the obstacle avoidance problem for a mobile robot or a manipulator in a known environment. Previous formulations of artificial potentials for obstacle avoidance have exhibited local minima in a cluttered environment. To build an artificial potential field, harmonic functions that completely eliminate local minima even for a cluttered environment are used. The panel method is employed to represent arbitrarily shaped obstacles and to derive the potential over the whole space. Based on this potential function, an elegant control strategy is proposed for the real-time control of a robot. The harmonic potential, the panel method, and the control strategy are tested with a bar-shaped mobile robot and a three-degree-of-freedom planar redundant manipulator.

  20. 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.

  1. A Collaborative Writing Mode for Avoiding Blind Modifications

    OpenAIRE

    Ignat, Claudia,; Oster, Gérald; Molli, Pascal; Skaf-Molli, Hala

    2007-01-01

    International audience; Existing collaborative environments such as Wiki or version control systems allow users to work in isolation, but they do not prevent blind modifications. For instance, users may concurrently perform the same task or they might work on obsolete versions of shared documents. We propose a novel writing mode for avoiding blind modifications by providing real-time information about group activities. Changes performed concurrently are filtered according to user privacy pref...

  2. A new method to avoid PPP in data evaluation

    Institute of Scientific and Technical Information of China (English)

    Chen Zhen-Peng; Sun Ye-Ying

    2004-01-01

    The Peelle Pertinent Puzzle (PPP) has been studied systematically. The results obtained by using several proposed methods to deal with a sample of 6Li(n, t) are compared with each other. The cause of PPP occurrence has been found.error according to the relative extent of discrepancy'. The method is able to produce the best result and should be used to avoid the PPP at first.

  3. AUV (REDERMOR) obstacle detection and avoidance experimental evaluation

    OpenAIRE

    Quidu, Isabelle; Hétet, Alain; Dupas, Yann; Lefèvre, Stéphanie

    2007-01-01

    International audience; Autonomous Underwater Vehicles (AUV) are expected to perform survey missions in both known and unknown environments. While the primary mission of an AUV is data collection, generally achieved with a sidescan sonar or a multibeam echosounder, another key task is to guaranty its own security. This paper deals with the problem of obstacle detection and avoidance by means of a forward looking sonar (FLS) mounted on the GESMA Redermor experimental AUV.

  4. An intelligent guidance and control system for ship obstacle avoidance

    OpenAIRE

    Harris, C J; Hong, X.; Wilson, P. A.

    1999-01-01

    An intelligent guidance and control system using a neurofuzzy network multistep ahead predictor model is introduced and applied to ship obstacle avoidance, which uses only observed input/output data generated by on board and external sensors, and a data fusion algorithm to generate the desired waypoints. A simple and effective waypoint guidance scheme based on line-of-sight is derived for a data based ship model. A neurofuzzy network predictor, based on using rudder deflection angle for the c...

  5. Earthworm (Eisenia andrei Avoidance of Soils Treated with Cypermethrin

    Directory of Open Access Journals (Sweden)

    Mara M. de Andréa

    2011-11-01

    Full Text Available The pyrethroid insecticide cypermethrin is used for agricultural and public health campaigns. Its residues may contaminate soils and the beneficial soil organisms, like the earthworms, that may ingest the contaminated soil particles. Due to its ecological relevance, earthworms Eisenia andrei/fetida have been used in different ecotoxicological tests. The avoidance of soils treated with cypermethrin by compost worms Eisenia andrei was studied here as a bioindicator of the influence of treatment dosage and the pesticide formulation in three different agricultural soils indicated by the Brazilian environmental authorities for ecotoxicological tests. This earthworms’ behavior was studied here as a first attempt to propose the test for regulation purposes. The two-compartment test systems, where the earthworms were placed for a two-day exposure period, contained samples of untreated soil alone or together with soil treated with technical grade or wettable powder formulation of cypermethrin. After 48 h, there was no mortality, but the avoidance was clear because all earthworms were found in the untreated section of each type of soil (p < 0.05. No differences were found by the Fisher’s exact test (p ≤ 1.000 for each soil and treatment, demonstrating that the different soil characteristics, the cypermethrin concentrations and formulation, as well as the smaller amounts of soil and earthworms did not influence the avoidance behavior of the earthworms to cypermethrin. The number and range of treatments used in this study do not allow a detailed recommendation of the conditions applied here, but to the best of our knowledge, this is the first reported attempt to identify the avoidance of pesticide treated tropical soils by earthworms.

  6. Collision Avoidance System (CAS): Human Factors Engineering Evaluation.

    Science.gov (United States)

    1982-12-01

    personnel indicated that the CAS console was much too big for the limited amount of space available on RANGER’s bridge. The console is 40 inches wide...avoidance (C/A) data. > RANGE * 12//2 < (T >~ LOG SPEED 4 10.0 KT < E1 i >~ HEADING 4 270 DEG * < J [ > BRGCRSR * 000 DEG4C/ ADATA < - > TRIAL SPD 4 0 <EJ

  7. 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.

  8. 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.

  9. Moisture conditions in buildings:how to avoid mould problems

    OpenAIRE

    Rode, Carsten

    2012-01-01

    Growth of mould requires the presence of moisture at a certain high level. In a heated indoor environment such moisture levels occur only if there is a reason for the moisture supply. Such moisture can come from the use of the building, because of malfunctioning constructions, or it can be the result of insufficient ventilation. The article will give an overview of these reasons, and thereby also give hints to how problems can be avoided.

  10. 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.

  11. The pathogen transmission avoidance theory of sexual selection

    Energy Technology Data Exchange (ETDEWEB)

    Loehle, C.

    1997-08-01

    The current theory that sexual selection results from female preference for males with good genes suffers from several problems. An alternative explanation, the pathogen transmission avoidance hypothesis, argues that the primary function of showy traits is to provide a reliable signal of current disease status, so that sick individuals can be avoided during mating. This study shows 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, which originate as exaggerations of normal traits that are indicative of good health (bright feathers, vigorous movement, large size). Thus, in this new model the origins of both showy traits and female choosiness are not problematic and there is no threshold effect. This model predicts that when the possession of male showy traits does not help to reduce disease in the female, showy traits are unlikely to occur. This case corresponds to thorough exposure of every animal to all group pathogens, on average, in large groups. Such species are shown with a large data set on birds to be less likely to exhibit showy traits. The good-genes model does not make this prediction. The pathogen transmission 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 can result in selection for resistance if such genes are present. Monogamy is argued to reduce selection pressures for showy traits; data show monogamous species to be both less parasitized and less showy. In the context of reduction of pathogen transmission rates in showy populations, selection pressure becomes inversely frequency-dependent, which makes showy traits likely to be self-limiting rather than runaway.

  12. Do Tetranychus urticae males avoid mating with familiar females?

    Science.gov (United States)

    Yoshioka, T; Yano, S

    2014-07-01

    The two-spotted spider mite, Tetranychus urticae, usually lives in kin groups under common webs. Because only the first mating results in fertilisation in female T. urticae, adult males guard quiescent deutonymph females, those at the stage immediately before maturation, to ensure paternity. Therefore, the cost of precopulatory guarding time seems considerable for males. Moreover, the fitness indices of daughters from intra-population crosses were significantly lower than those of daughters from inter-population crosses, indicating that inbreeding depression exists in T. urticae. Therefore, we hypothesised that T. urticae males should be choosy in guarding familiar females to avoid inbreeding depression. Furthermore, webs should be a key element of the environment shared by familiar individuals. In this study, we demonstrated the inbreeding avoidance mechanism of T. urticae males in relation to webs produced by familiar females (known webs) or unfamiliar females (unknown webs). Regardless of surrounding webs (known or unknown), males preferred unfamiliar to familiar females. We further examined whether males detect unfamiliar females by their webs. When males had experienced a female's web without encountering that female, they subsequently preferred females that did not produce the surrounding webs in which the choice experiment was conducted. Results suggest that putative kin recognition for inbreeding avoidance in T. urticae males is based on the relationship between webs and females, and not on the discrimination of webs in shared environments.

  13. A Robot Manipulator with Adaptive Fuzzy Controller in Obstacle Avoidance

    Science.gov (United States)

    Sreekumar, Muthuswamy

    2016-07-01

    Building robots and machines to act within a fuzzy environment is a problem featuring complexity and ambiguity. In order to avoid obstacles, or move away from it, the robot has to perform functions such as obstacle identification, finding the location of the obstacle, its velocity, direction of movement, size, shape, and so on. This paper presents about the design, and implementation of an adaptive fuzzy controller designed for a 3 degree of freedom spherical coordinate robotic manipulator interfaced with a microcontroller and an ultrasonic sensor. Distance between the obstacle and the sensor and its time rate are considered as inputs to the controller and how the manipulator to take diversion from its planned trajectory, in order to avoid collision with the obstacle, is treated as output from the controller. The obstacles are identified as stationary or moving objects and accordingly adaptive self tuning is accomplished with three set of linguistic rules. The prototype of the manipulator has been fabricated and tested for collision avoidance by placing stationary and moving obstacles in its planned trajectory. The performance of the adaptive control algorithm is analyzed in MATLAB by generating 3D fuzzy control surfaces.

  14. Autonomous obstacle avoidance using visual fixation and looming

    Science.gov (United States)

    Joarder, Kunal; Raviv, Daniel

    1992-11-01

    This paper describes a vision-based method for avoiding obstacles using the concepts of visual looming and fixating motion. Visual looming refers to the expansion of images of objects in the retina. Usually, this is due to the decreasing distance between the observer and the object. An increasing looming value signifies an increasing threat of collision with the object. The visual task of avoiding collision can be further simplified by purposive control of visual fixation at the objects in front of the moving camera. Using these two basic concepts real time obstacle avoidance in a tight perception-action loop is implemented. Three-dimensional space in front of the camera is divided into zones with various degrees of looming-based threat of collision. For each obstacle seen by a fixating camera, looming and its time derivative are calculated directly from the 2-D image. Depending on the threat posed by an obstacle, a course change is dictated. This looming based approach is simple, independent of the size of the 3-D object and its range and involves simple quantitative measurements. Results pertinent to a camera on a robot arm navigating between obstacles are presented.

  15. The influence of object identity on obstacle avoidance reaching behaviour.

    Science.gov (United States)

    de Haan, A M; Van der Stigchel, S; Nijnens, C M; Dijkerman, H C

    2014-07-01

    When reaching for target objects, we hardly ever collide with other objects located in our working environment. Behavioural studies have demonstrated that the introduction of non-target objects into the workspace alters both spatial and temporal parameters of reaching trajectories. Previous studies have shown the influence of spatial object features (e.g. size and position) on obstacle avoidance movements. However, obstacle identity may also play a role in the preparation of avoidance responses as this allows prediction of possible negative consequences of collision based on recognition of the obstacle. In this study we test this hypothesis by asking participants to reach towards a target as quickly as possible, in the presence of an empty or full glass of water placed about half way between the target and the starting position, at 8 cm either left or right of the virtual midline. While the spatial features of full and empty glasses of water are the same, the consequences of collision are clearly different. Indeed, when there was a high chance of collision, reaching trajectories veered away more from filled than from empty glasses. This shows that the identity of potential obstacles, which allows for estimating the predicted consequences of collision, is taken into account during obstacle avoidance.

  16. Hierarchical brain networks active in approach and avoidance goal pursuit

    Directory of Open Access Journals (Sweden)

    Jeffrey Martin Spielberg

    2013-06-01

    Full Text Available Effective approach/avoidance goal pursuit is critical for attaining long-term health and well-being. Research on the neural correlates of key goal pursuit processes (e.g., motivation has long been of interest, with lateralization in prefrontal cortex being a particularly fruitful target of investigation. However, this literature has often been limited by a lack of spatial specificity and has not delineated the precise aspects of approach/avoidance motivation involved. Additionally, the relationships among brain regions (i.e., network connectivity vital to goal pursuit remain largely unexplored. Specificity in location, process, and network relationship is vital for moving beyond gross characterizations of function and identifying the precise cortical mechanisms involved in motivation. The present paper integrates research using more spatially specific methodologies (e.g., functional magnetic resonance imaging with the rich psychological literature on approach/avoidance to propose an integrative network model that takes advantage of the strengths of each of these literatures.

  17. Difficulties in avoiding exposure to allergens in cosmetics

    DEFF Research Database (Denmark)

    Larsen, Kristian

    2007-01-01

    The aim of the study is to describe the ability of patients with allergic contact dermatitis to avoid exposure to allergens in cosmetics. The study is a questionnaire survey among 382 patients with contact allergy to preservatives and fragrances, included from 3 dermatological clinics. The questi......The aim of the study is to describe the ability of patients with allergic contact dermatitis to avoid exposure to allergens in cosmetics. The study is a questionnaire survey among 382 patients with contact allergy to preservatives and fragrances, included from 3 dermatological clinics....... The questionnaire included questions about the level of difficulty in reading labels of ingredients on cosmetics and about patients' strategies to avoid substances they were allergic to. It also included questions about eczema severity as well as about educational level. 46% of the patients found it difficult...... or extremely difficult to read the ingredient labelling of cosmetics, and this finding was significantly related to low educational level. Patients allergic to formaldehyde and methyldibromo glutaronitrile experienced the worst difficulties, while patients with fragrance allergy found ingredient label reading...

  18. Reproductive efficiency and shade avoidance plasticity under simulated competition.

    Science.gov (United States)

    Fazlioglu, Fatih; Al-Namazi, Ali; Bonser, Stephen P

    2016-07-01

    Plant strategy and life-history theories make different predictions about reproductive efficiency under competition. While strategy theory suggests under intense competition iteroparous perennial plants delay reproduction and semelparous annuals reproduce quickly, life-history theory predicts both annual and perennial plants increase resource allocation to reproduction under intense competition. We tested (1) how simulated competition influences reproductive efficiency and competitive ability (CA) of different plant life histories and growth forms; (2) whether life history or growth form is associated with CA; (3) whether shade avoidance plasticity is connected to reproductive efficiency under simulated competition. We examined plastic responses of 11 herbaceous species representing different life histories and growth forms to simulated competition (spectral shade). We found that both annual and perennial plants invested more to reproduction under simulated competition in accordance with life-history theory predictions. There was no significant difference between competitive abilities of different life histories, but across growth forms, erect species expressed greater CA (in terms of leaf number) than other growth forms. We also found that shade avoidance plasticity can increase the reproductive efficiency by capitalizing on the early life resource acquisition and conversion of these resources into reproduction. Therefore, we suggest that a reassessment of the interpretation of shade avoidance plasticity is necessary by revealing its role in reproduction, not only in competition of plants.

  19. Werner's Measure on Self-Avoiding Loops and Welding

    Science.gov (United States)

    Chavez, Angel; Pickrell, Doug

    2014-08-01

    Werner's conformally invariant family of measures on self-avoiding loops on Riemann surfaces is determined by a single measure μ_0 on self-avoiding loops in C setminus{0} which surround 0. Our first major objective is to show that the measure μ_0 is infinitesimally invariant with respect to conformal vector fields (essentially the Virasoro algebra of conformal field theory). This makes essential use of classical variational formulas of Duren and Schiffer, which we recast in representation theoretic terms for efficient computation. We secondly show how these formulas can be used to calculate (in principle, and sometimes explicitly) quantities (such as moments for coefficients of univalent functions) associated to the conformal welding for a self-avoiding loop. This gives an alternate proof of the uniqueness of Werner's measure. We also attempt to use these variational formulas to derive a differential equation for the (Laplace transform of) the ''diagonal distribution'' for the conformal welding associated to a loop; this generalizes in a suggestive way to a deformation of Werner's measure conjectured to exist by Kontsevich and Suhov (a basic inspiration for this paper).

  20. Disruption avoidance through active magnetic feedback in tokamak plasmas

    Science.gov (United States)

    Paccagnella, Roberto; Zanca, Paolo; Yanovskiy, Vadim; Finotti, Claudio; Manduchi, Gabriele; Piron, Chiara; Carraro, Lorella; Franz, Paolo; RFX Team

    2014-10-01

    Disruptions avoidance and mitigation is a fundamental need for a fusion relevant tokamak. In this paper a new experimental approach for disruption avoidance using active magnetic feedback is presented. This scheme has been implemented and tested on the RFX-mod device operating as a circular tokamak. RFX-mod has a very complete system designed for active mode control that has been proved successful for the stabilization of the Resistive Wall Modes (RWMs). In particular the current driven 2/1 mode, unstable when the edge safety factor, qa, is around (or even less than) 2, has been shown to be fully and robustly stabilized. However, at values of qa (qa > 3), the control of the tearing 2/1 mode has been proved difficult. These results suggested the idea to prevent disruptions by suddenly lowering qa to values around 2 where the tearing 2/1 is converted to a RWM. Contrary to the universally accepted idea that the tokamaks should disrupt at low qa, we demonstrate that in presence of a well designed active control system, tokamak plasmas can be driven to low qa actively stabilized states avoiding plasma disruption with practically no loss of the plasma internal energy.