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Sample records for underwent extinction sessions

  1. Effects of memory age and interval of fear extinction sessions on contextual fear extinction.

    Science.gov (United States)

    Matsuda, Shingo; Matsuzawa, Daisuke; Ishii, Daisuke; Tomizawa, Haruna; Shimizu, Eiji

    2014-08-22

    Fear extinction is a major task in our understanding of the biological mechanisms of exposure therapy, one of the most used treatments for stress-related disorders. It was recently reported that an extinction of 5 consecutive days prevents spontaneous recovery of fear memory. Memory age and the timing of fear extinction influence the effect of fear extinction. In this study, we used contextual fear extinction in adult male mice to examine whether memory age influences an extinction of 5 consecutive days and whether consecutiveness is necessary to prevent spontaneous recovery. Our results showed that, although fear memory was not affected by the passage of time, the old fear memory (28 days after fear conditioning) was more sensitive to fear extinction than the young fear memory (7 days after fear conditioning). Additionally, we demonstrated that consecutiveness of extinction sessions is not necessary to prevent spontaneous recovery. Instead, fear extinction sessions at spaced intervals were found to be more effective than consecutive extinction sessions for young fear memory. Our results suggest that taking memory age and the interval of fear extinction sessions into consideration would help to optimize exposure therapy. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  2. Spacing extinction sessions as a behavioral technique for preventing relapse in an animal model of voluntary actions.

    Science.gov (United States)

    Bernal-Gamboa, Rodolfo; Gámez, A Matías; Nieto, Javier

    2018-06-01

    Instrumental extinction has been proposed as a model for understanding the suppression of problematic voluntary actions. Consequently, it has been suggested that response recovery after extinction could model relapse. Four experiments with rats used a free operant procedure to explore the impact of spacing extinction sessions on spontaneous recovery, renewal, reinstatement, and rapid reacquisition of extinguished lever-pressing. Initially, in all experiments, hungry rats were trained to perform two responses (R1 and R2) for food. Then, all responses underwent extinction. For R1, rats experienced a longer intersession interval (72 h) than for R2 (24 h). During the final restoration test, it was observed that using spaced extinction sessions reduced spontaneous recovery, renewal, and reinstatement. However, implementing a longer intersession interval throughout extinction exposure did not slow the rate of reacquisition of operant responses. The present findings suggest that in most cases extinction is more enduring when the extinction sessions are spaced. Since expanding the intersession interval during extinction might be interpreted as conducting extinction in multiple temporal contexts, the overall pattern of results was explained based on contextual modulation. Copyright © 2018 Elsevier B.V. All rights reserved.

  3. Within-session analysis of the extinction of pavlovian fear-conditioning using robust regression

    Directory of Open Access Journals (Sweden)

    Vargas-Irwin, Cristina

    2010-06-01

    Full Text Available Traditionally , the analysis of extinction data in fear conditioning experiments has involved the use of standard linear models, mostly ANOVA of between-group differences of subjects that have undergone different extinction protocols, pharmacological manipulations or some other treatment. Although some studies report individual differences in quantities such as suppression rates or freezing percentages, these differences are not included in the statistical modeling. Withinsubject response patterns are then averaged using coarse-grain time windows which can overlook these individual performance dynamics. Here we illustrate an alternative analytical procedure consisting of 2 steps: the estimation of a trend for within-session data and analysis of group differences in trend as main outcome. This procedure is tested on real fear-conditioning extinction data, comparing trend estimates via Ordinary Least Squares (OLS and robust Least Median of Squares (LMS regression estimates, as well as comparing between-group differences and analyzing mean freezing percentage versus LMS slopes as outcomes

  4. Effects of post-session administration of methylene blue on fear extinction and contextual memory in adults with claustrophobia

    NARCIS (Netherlands)

    Telch, M.J.; Bruchey, A.K.; Rosenfield, D.; Cobb, A.R.; Smits, J.A.J.; Pahl, S.; Gonzalez-Lima, F.

    2014-01-01

    Administering methylene blue, a memory-enhancing agent, after successful exposure therapy promoted the retention of fear extinction in claustrophobic patients, but clinicians should carefully consider what level of fear reduction was achieved in session to avoid harmful

  5. Effects of Post-Session Administration of Methylene Blue on Fear Extinction and Contextual Memory in Adults With Claustrophobia

    NARCIS (Netherlands)

    Telch, M.J.; Bruchey, A.K.; Rosenfield, D.; Cobb, A.R.; Smits, J.A.J.; Pahl, S.; Gonzalez-Lima, F.

    2014-01-01

    Administering methylene blue, a memory-enhancing agent, after successful exposure therapy promoted the retention of fear extinction in claustrophobic patients, but clinicians should carefully consider what level of fear reduction was achieved in session to avoid harmful

  6. Paired-housing selectively facilitates within-session extinction of avoidance behavior, and increases c-Fos expression in the medial prefrontal cortex, in anxiety vulnerable Wistar-Kyoto rats.

    Science.gov (United States)

    Smith, Ian M; Pang, Kevin C H; Servatius, Richard J; Jiao, Xilu; Beck, Kevin D

    2016-10-01

    The perseveration of avoidance behavior, even in the absence of once threatening stimuli, is a key feature of anxiety and related psychiatric conditions. This phenomenon can be observed in the Wistar-Kyoto (WKY) rat which, in comparison to outbred controls, demonstrates impaired extinction of avoidance behavior. Also characteristic of the WKY rat is abnormalities of the neurocircuitry and neuroplasticity of the medial prefrontal cortex (mPFC). One means of reducing physiological responses to anxiety, and conditioned fear, in social species is the presence of a conspecific animal. The current study investigates whether or not pair-housed WKY rats would show facilitated extinction of avoidance in comparison to individual-housed WKY rats, and whether or not pair-housing influences mPFC activation during lever-press avoidance. Male WKY rats were assigned to individual-housed and pair-housed conditions. Rats were trained in lever-press avoidance. Each session of lever-press avoidance consisted of 20 trials, where pressing a lever in response to a warning tone prevented foot-shocks. Rats received 12 acquisition sessions over 4weeks; followed by 6 extinction sessions over 2weeks, where foot-shocks ceased to be delivered. Brains were harvested 90min after trials 1 and 10 of extinction sessions 1 and 6, and mPFC sections underwent c-Fos staining as a measure of activation. Pair-housed rats showed facilitated lever-press avoidance extinction rates, but the main cause for this overall difference was a selective facilitation of within-session extinction. Similar to individual-housed rats, pair-housed rats continued to avoid during trial 1 of extinction even when the avoidance responding had been significantly reduced by the end of the previous session. Pair-housed rats sacrificed on trial 1 showed greater c-Fos expression in the anterior cingulate cortex and prelimbic cortex subregions of the mPFC compared individual-housed rats sacrificed on trial 1. This data shows pair

  7. Calcineurin Inhibition Blocks Within-, but Not Between-Session Fear Extinction in Mice

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    Almeida-Corrêa, Suellen; Moulin, Thiago C.; Carneiro, Clarissa F. D.; Gonçalves, Marina M. C.; Junqueira, Lara S.; Amaral, Olavo B.

    2015-01-01

    Memory extinction involves the formation of a new associative memory that inhibits a previously conditioned association. Nonetheless, it could also depend on weakening of the original memory trace if extinction is assumed to have multiple components. The phosphatase calcineurin (CaN) has been described as being involved in extinction but not in…

  8. Effects of post-session administration of methylene blue on fear extinction and contextual memory in adults with claustrophobia.

    Science.gov (United States)

    Telch, Michael J; Bruchey, Aleksandra K; Rosenfield, David; Cobb, Adam R; Smits, Jasper; Pahl, Sandra; Gonzalez-Lima, F

    2014-10-01

    Preclinical studies have shown that low-dose methylene blue increases mitochondrial cytochrome oxidase activity in the brain and improves memory retention after learning tasks, including fear extinction. The authors report on the first controlled experiment to examine the memory-enhancing effects of posttraining methylene blue administration on retention of fear extinction and contextual memory following fear extinction training. Adult participants displaying marked claustrophobic fear were randomly assigned to double-blind administration of 260 mg of methylene blue (N=23) or administration of placebo (N=19) immediately following six 5-minute extinction trials in an enclosed chamber. Retesting occurred 1 month later to assess fear renewal as indexed by peak fear during exposure to a nontraining chamber, with the prediction that the effects of methylene blue would vary as a function of fear reduction achieved during extinction training. Incidental contextual memory was assessed 1 and 30 days after training to assess the cognitive-enhancing effects of methylene blue independent of its effects on fear attenuation. Consistent with predictions, participants displaying low end fear posttraining showed significantly less fear at the 1-month follow-up if they received methylene blue posttraining compared with placebo. In contrast, participants displaying moderate to high levels of posttraining fear tended to fare worse at the follow-up if they received methylene blue posttraining. Methylene blue's enhancement of contextual memory was unrelated to initial or posttraining claustrophobic fear. Methylene blue enhances memory and the retention of fear extinction when administered after a successful exposure session but may have a deleterious effect on extinction when administered after an unsuccessful exposure session.

  9. Post-Session Administration of USP Methylene Blue Facilitates the Retention of Pathological Fear Extinction and Contextual Memory in Phobic Adults

    Science.gov (United States)

    Telch, Michael J.; Bruchey, Aleksandra K.; Rosenfield, David; Cobb, Adam R.; Smits, Jasper; Pahl, Sandra; Gonzalez-Lima, F.

    2015-01-01

    Objective Preclinical studies have shown that low-dose USP methylene blue increases mitochondrial cytochrome oxidase activity in the brain and improves memory retention after learning tasks, including fear extinction. We report on the first controlled experiment to examine the memory-enhancing effects of post-training methylene blue administration on retention of fear extinction and contextual memory following fear extinction training. Method Adults (N = 42) displaying marked claustrophobic fear were randomized to double-blind administration of 260 mg of methylene blue versus placebo immediately following six five-minute extinction trials to an enclosed chamber. Retesting occurred one month later to assess fear renewal as indexed by peak fear during exposure to a non-trained enclosed chamber with the prediction that methylene blue's effects would vary as a function of fear reduction achieved during extinction training. Incidental contextual memory was assessed 1 and 30 days after training to assess the cognitive enhancing effects of methylene blue independent of its effects on fear attenuation. Results Consistent with predictions, participants displaying low end fear at post-training showed significantly less fear at follow-up if they received methylene blue post-training relative to placebo. In contrast, participants displaying moderate to high levels of post-training fear tended to fare worse at follow-up relative to placebo. Methylene blue's enhancement of contextual memory was unrelated to initial or post-training claustrophobic fear. Conclusions Methylene blue enhances memory and the retention of fear extinction when administered after a successful exposure session, but may have a deleterious effect on extinction when administered after an unsuccessful exposure session. PMID:25018057

  10. Associative learning versus fear habituation as predictors of long-term extinction retention.

    Science.gov (United States)

    Brown, Lily A; LeBeau, Richard T; Chat, Ka Yi; Craske, Michelle G

    2017-06-01

    Violation of unconditioned stimulus (US) expectancy during extinction training may enhance associative learning and result in improved long-term extinction retention compared to within-session habituation. This experiment examines variation in US expectancy (i.e., expectancy violation) as a predictor of long-term extinction retention. It also examines within-session habituation of fear-potentiated startle (electromyography, EMG) and fear of conditioned stimuli (CS) throughout extinction training as predictors of extinction retention. Participants (n = 63) underwent fear conditioning, extinction and retention and provided continuous ratings of US expectancy and EMG, as well as CS fear ratings before and after each phase. Variation in US expectancy throughout extinction and habituation of EMG and fear was entered into a regression as predictors of retention and reinstatement of levels of expectancy and fear. Greater variation in US expectancy throughout extinction training was significantly predictive of enhanced extinction performance measured at retention test, although not after reinstatement test. Slope of EMG and CS fear during extinction did not predict retention of extinction. Within-session habituation of EMG and self-reported fear is not sufficient for long-term retention of extinction learning, and models emphasizing expectation violation may result in enhanced outcomes.

  11. Orexin/hypocretin receptor 1 signaling mediates Pavlovian cue-food conditioning and extinction.

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    Keefer, Sara E; Cole, Sindy; Petrovich, Gorica D

    2016-08-01

    Learned food cues can drive feeding in the absence of hunger, and orexin/hypocretin signaling is necessary for this type of overeating. The current study examined whether orexin also mediates cue-food learning during the acquisition and extinction of these associations. In Experiment 1, rats underwent two sessions of Pavlovian appetitive conditioning, consisting of tone-food presentations. Prior to each session, rats received either the orexin 1 receptor antagonist SB-334867 (SB) or vehicle systemically. SB treatment did not affect conditioned responses during the first conditioning session, measured as food cup behavior during the tone and latency to approach the food cup after the tone onset, compared to the vehicle group. During the second conditioning session, SB treatment attenuated learning. All groups that received SB, prior to either the first or second conditioning session, displayed significantly less food cup behavior and had longer latencies to approach the food cup after tone onset compared to the vehicle group. These findings suggest orexin signaling at the 1 receptor mediates the consolidation and recall of cue-food acquisition. In Experiment 2, another group of rats underwent tone-food conditioning sessions (drug free), followed by two extinction sessions under either SB or vehicle treatment. Similar to Experiment 1, SB did not affect conditioned responses during the first session. During the second extinction session, the group that received SB prior to the first extinction session, but vehicle prior to the second, expressed conditioned food cup responses longer after tone offset, when the pellets were previously delivered during conditioning, and maintained shorter latencies to approach the food cup compared to the other groups. The persistence of these conditioned behaviors indicates impairment in extinction consolidation due to SB treatment during the first extinction session. Together, these results demonstrate an important role for orexin

  12. Effects of extinction in multiple contexts on renewal of instrumental responses.

    Science.gov (United States)

    Bernal-Gamboa, Rodolfo; Nieto, Javier; Uengoer, Metin

    2017-09-01

    In two experiments with rats, we investigated the effects of using multiple contexts during extinction on renewal of lever-pressing behavior. During the first phase of both experiments, rats were reinforced to press a lever for food in Context A. Then, responses underwent extinction. For half of the animals, extinction sessions were conducted in a single context, whereas the other half received extinction in three different contexts. In Experiment 1, we observed that extinction in multiple contexts eliminated ABC renewal, but had no detectable impact on ABA renewal. Experiment 2 revealed that conducting extended extinction training in multiple contexts attenuated ABA renewal. Theoretical and clinical implications of the present findings are discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Amount of fear extinction changes its underlying mechanisms.

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    An, Bobae; Kim, Jihye; Park, Kyungjoon; Lee, Sukwon; Song, Sukwoon; Choi, Sukwoo

    2017-07-03

    There has been a longstanding debate on whether original fear memory is inhibited or erased after extinction. One possibility that reconciles this uncertainty is that the inhibition and erasure mechanisms are engaged in different phases (early or late) of extinction. In this study, using single-session extinction training and its repetition (multiple-session extinction training), we investigated the inhibition and erasure mechanisms in the prefrontal cortex and amygdala of rats, where neural circuits underlying extinction reside. The inhibition mechanism was prevalent with single-session extinction training but faded when single-session extinction training was repeated. In contrast, the erasure mechanism became prevalent when single-session extinction training was repeated. Moreover, ablating the intercalated neurons of amygdala, which are responsible for maintaining extinction-induced inhibition, was no longer effective in multiple-session extinction training. We propose that the inhibition mechanism operates primarily in the early phase of extinction training, and the erasure mechanism takes over after that.

  14. Dopamine efflux in the nucleus accumbens during within-session extinction, outcome-dependent, and habit-based instrumental responding for food reward.

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    Ahn, Soyon; Phillips, Anthony G

    2007-04-01

    Dopamine (DA) activity in the nucleus accumbens (NAc) is related to the general motivational effects of rewarding stimuli. Dickinson and colleagues have shown that initial acquisition of instrumental responding reflects action-outcome relationships based on instrumental incentive learning, which establishes the value of an outcome. Given that the sensitivity of responding to outcome devaluation is not affected by NAc lesions, it is unlikely that incentive learning during the action-outcome phase is mediated by DA activity in the NAc. DA efflux in the NAc after limited and extended training was compared on the assumption that comparable changes would be observed during both action-outcome- and habit-based phases of instrumental responding for food. This study also tested the hypothesis that increase in NAc DA activity is correlated with instrumental responding during extinction maintained by a conditioned stimulus paired with food. Rats were trained to lever press for food (random-interval 30 s schedule). On the 5th and 16th day of training, microdialysis samples were collected from the NAc or mediodorsal striatum (a control site for generalized activity) during instrumental responding in extinction and then for food reward, and analyzed for DA content using high performance liquid chromatography. Increase in DA efflux in the NAc accompanied responding for food pellets on both days 5 and 16, with the magnitude of increase significantly enhanced on day 16. DA efflux was also significantly elevated during responding in extinction only on day 16. These results support a role for NAc DA activity in Pavlovian, but not instrumental, incentive learning.

  15. Are extinction opinions extinct?

    Directory of Open Access Journals (Sweden)

    Tamsin E. Lee

    2017-08-01

    Full Text Available Extinction models vary in the information they require, the simplest considering the rate of certain sightings only. More complicated methods include uncertain sightings and allow for variation in the reliability of uncertain sightings. Generally extinction models require expert opinion, either as a prior belief that a species is extinct, or to establish the quality of a sighting record, or both. Is this subjectivity necessary? We present two models to explore whether the individual quality of sightings, judged by experts, is strongly informative of the probability of extinction: the ‘quality breakpoint method’ and the ‘quality as variance method’. For the first method we use the Barbary lion as an exemplar. For the second method we use the Barbary lion, Alaotra grebe, Jamaican petrel and Pohnpei starling as exemplars. The ‘quality breakpoint method’ uses certain and uncertain sighting records, and the quality of uncertain records, to establish whether a change point in the rate of sightings can be established using a simultaneous Bayesian optimisation with a non-informative prior. For the Barbary lion, there is a change in subjective quality of sightings around 1930. Unexpectedly sighting quality increases after this date. This suggests that including quality scores from experts can lead to irregular effects and may not offer reliable results. As an alternative, we use quality as a measure of variance around the sightings, not a change in quality. This leads to predictions with larger standard deviations, however the results remain consistent across any prior belief of extinction. Nonetheless, replacing actual quality scores with random quality scores showed little difference, inferring that the quality scores from experts are superfluous. Therefore, we deem the expensive process of obtaining pooled expert estimates as unnecessary, and even when used we recommend that sighting data should have minimal input from experts in terms of

  16. Rethinking Extinction

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    Dunsmoor, Joseph E.; Niv, Yael; Daw, Nathaniel; Phelps, Elizabeth A.

    2015-01-01

    Extinction serves as the leading theoretical framework and experimental model to describe how learned behaviors diminish through absence of anticipated reinforcement. In the past decade, extinction has moved beyond the realm of associative learning theory and behavioral experimentation in animals and has become a topic of considerable interest in the neuroscience of learning, memory, and emotion. Here, we review research and theories of extinction, both as a learning process and as a behavioral technique, and consider whether traditional understandings warrant a re-examination. We discuss the neurobiology, cognitive factors, and major computational theories, and revisit the predominant view that extinction results in new learning that interferes with expression of the original memory. Additionally, we reconsider the limitations of extinction as a technique to prevent the relapse of maladaptive behavior, and discuss novel approaches, informed by contemporary theoretical advances, that augment traditional extinction methods to target and potentially alter maladaptive memories. PMID:26447572

  17. Rethinking Extinction.

    Science.gov (United States)

    Dunsmoor, Joseph E; Niv, Yael; Daw, Nathaniel; Phelps, Elizabeth A

    2015-10-07

    Extinction serves as the leading theoretical framework and experimental model to describe how learned behaviors diminish through absence of anticipated reinforcement. In the past decade, extinction has moved beyond the realm of associative learning theory and behavioral experimentation in animals and has become a topic of considerable interest in the neuroscience of learning, memory, and emotion. Here, we review research and theories of extinction, both as a learning process and as a behavioral technique, and consider whether traditional understandings warrant a re-examination. We discuss the neurobiology, cognitive factors, and major computational theories, and revisit the predominant view that extinction results in new learning that interferes with expression of the original memory. Additionally, we reconsider the limitations of extinction as a technique to prevent the relapse of maladaptive behavior and discuss novel approaches, informed by contemporary theoretical advances, that augment traditional extinction methods to target and potentially alter maladaptive memories. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Rethinking Extinction

    OpenAIRE

    Dunsmoor, Joseph E.; Niv, Yael; Daw, Nathaniel; Phelps, Elizabeth A.

    2015-01-01

    Extinction serves as the leading theoretical framework and experimental model to describe how learned behaviors diminish through absence of anticipated reinforcement. In the past decade, extinction has moved beyond the realm of associative learning theory and behavioral experimentation in animals and has become a topic of considerable interest in the neuroscience of learning, memory, and emotion. Here, we review research and theories of extinction, both as a learning process and as a behavior...

  19. Activation of AMPA receptor in the infralimbic cortex facilitates extinction and attenuates the heroin-seeking behavior in rats.

    Science.gov (United States)

    Chen, Weisheng; Wang, Yiqi; Sun, Anna; Zhou, Linyi; Xu, Wenjin; Zhu, Huaqiang; Zhuang, Dingding; Lai, Miaojun; Zhang, Fuqiang; Zhou, Wenhua; Liu, Huifen

    2016-01-26

    Infralimbic cortex (IL) is proposed to suppress cocaine seeking after extinction, but whether the IL regulates the extinction and reinstatement of heroin-seeking behavior is unknown. To address this issue, the male SD rats were trained to self-administer heroin under a FR1 schedule for consecutive 14 days, then the rats underwent 7 daily 2h extinction session in the operant chamber. The activation of IL by microinjection PEPA, an allosteric AMPA receptor potentiator into IL before each of extinction session facilitated the extinction responding after heroin self-administration, but did not alter the locomotor activity in an open field testing environment. Other rats were first trained under a FR1 schedule for heroin self-administration for 14 days, followed by 14 days of extinction training, and reinstatement of heroin-seeking induced by cues was measured for 2h. Intra-IL microinjecting of PEPA at 15min prior to test inhibited the reinstatement of heroin-seeking induced by cues. Moreover, the expression of GluR1 in the IL and NAc remarkably increased after treatment with PEPA during the reinstatement. These finding suggested that activation of glutamatergic projection from IL to NAc shell may be involved in the extinction and reinstatement of heroin-seeking. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  20. Facilitation of extinction and re-extinction of operant behavior in mice by chlordiazepoxide and D-cycloserine.

    Science.gov (United States)

    Leslie, Julian C; Norwood, Kelly

    2013-05-01

    The aim was to compare operant extinction with re-extinction following re-acquisition and to investigate neuropharmacological mechanisms through administration of drugs potentiating GABAergic or glutamatergic systems. Groups of C57Bl/6 mice were trained to lever press for food on a fixed ratio schedule, then extinguished with or without pre-session chlordiazepoxide or post-session d-cycloserine administration (15mg/kg in each case), then retrained to lever press for food, then re-extinguished with or without pre-session chlordiazepoxide or post-session d-cycloserine. Under vehicle injections, extinction and re-extinction curves were indistinguishable, but drug treatments showed that there was less resistance to extinction in the re-extinction phase. Chlordiazepoxide facilitated extinction and re-extinction, with an earlier effect during re-extinction. d-Cycloserine also facilitated extinction and re-extinction, with some evidence of an earlier effect during re-extinction. These results replicate and extend earlier findings with operant extinction, but differ from some previous reports of d-cycloserine on re-extinction of Pavlovian conditioned fear. Implications for accounts of the similarities and differences between neural mechanisms of extinction following either Pavlovian or operant conditioning, and applications of these findings, are discussed. Copyright © 2013 Elsevier Inc. All rights reserved.

  1. Compound Stimulus Extinction Reduces Spontaneous Recovery in Humans

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    Coelho, Cesar A. O.; Dunsmoor, Joseph E.; Phelps, Elizabeth A.

    2015-01-01

    Fear-related behaviors are prone to relapse following extinction. We tested in humans a compound extinction design ("deepened extinction") shown in animal studies to reduce post-extinction fear recovery. Adult subjects underwent fear conditioning to a visual and an auditory conditioned stimulus (CSA and CSB, respectively) separately…

  2. The effect of electroacupuncture on extinction responding of heroin-seeking behavior and FosB expression in the nucleus accumbens core.

    Science.gov (United States)

    Hu, Airong; Lai, Miaojun; Wei, Jianzi; Wang, Lina; Mao, Huijuan; Zhou, Wenhua; Liu, Sheng

    2013-02-08

    Augmentation of extinction with learning enhancing therapy may offer an effective strategy to combat heroin relapse. Our lab previously found that electroacupuncture (EA) not only significantly reduced cue-induced reinstatement of heroin seeking but also exhibited a promoting effect on the ability of learning and memory. In the present study, we further investigated the effects of EA on the extinction of heroin-seeking behavior in rats with a history of intravenous heroin self-administration. We trained Sprague-Dawley rats to nose-poke for i.v. heroin either daily for 4h or 25 infusions for 14 consecutive days; then the rats underwent 7 daily 3h extinction sessions in the operant chamber. To assess EA's effects on the extinction response of heroin-associated cues, 2Hz EA was administered 1h before each of the 7 extinction sessions. We also applied immunohistochemistry to detect FosB-positive nuclei in the nucleus accumbens core. We found that EA treatment facilitated the extinction response of heroin seeking but did not alter the locomotor activity in an open field testing environment. EA stimulation attenuated the FosB expression in the core of the nucleus accumbens, a brain region involved in the learning and execution of motor responses. Altogether, these results suggest that EA may provide a novel nonpharmacological approach to enhance extinction learning when combined with extinction therapy for the treatment of heroin addiction. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  3. Sleep Deprivation Disrupts Recall of Conditioned Fear Extinction.

    Science.gov (United States)

    Straus, Laura D; Acheson, Dean T; Risbrough, Victoria B; Drummond, Sean P A

    2017-03-01

    Learned fear is crucial in the development and maintenance of posttraumatic stress disorder (PTSD) and other anxiety disorders, and extinction of learned fear is necessary for response to exposure-based treatments. In humans, research suggests disrupted sleep impairs consolidation of extinction, though no studies have examined this experimentally using total sleep deprivation. Seventy-one healthy controls underwent a paradigm to acquire conditioned fear to a visual cue. Twenty-four hours after fear conditioning, participants underwent extinction learning. Twenty-four hours after extinction learning, participants underwent extinction recall. Participants were randomized to three groups: 1) well-rested throughout testing ("normal sleep"; n = 21); 2) 36 hours total sleep deprivation before extinction learning ("pre-extinction deprivation"; n = 25); or 3) 36 hours total sleep deprivation after extinction learning and before extinction recall ("post-extinction deprivation"; n = 25). The groups were compared on blink EMG reactivity to the condition stimulus during extinction learning and recall. There were no differences among the three groups during extinction learning. During extinction recall, the pre-extinction deprivation group demonstrated significantly less extinction recall than the normal sleep group. There was no significant difference between the normal sleep and post-extinction deprivation group during extinction recall. Results indicated sleep deprivation prior to extinction training significantly disrupts extinction recall. These findings suggest that (1) sleep deprivation in the immediate aftermath of trauma could be a potential contributor to PTSD development and maintenance via interference with natural extinction processes and (2) management of sleep symptoms should be considered during extinction-based therapy.

  4. Interoceptive conditioning with nicotine using extinction and re-extinction to assess stimulus similarity with bupropion

    Science.gov (United States)

    Charntikov, Sergios; deWit, Nicole R.; Bevins, Rick A

    2014-01-01

    Bupropion is an atypical antidepressant that increases long-term quit rates of tobacco smokers. A better understanding of the relation between nicotine and this first-line medication may provide insight into improving treatment. For all experiments, rats first had nicotine (0.4 mg base/kg) and saline session intermixed; intermittent access to sucrose only occurred on nicotine session. Nicotine in this protocol comes to differentially control “anticipatory” dipper entries. To more closely examine the overlap in the interoceptive stimulus effects of nicotine and bupropion, we assessed whether subsequent prolonged and repeated non-reinforced (extinction) sessions with the bupropion stimulus could weaken responding to nicotine (i.e., transfer of extinction). We also examined whether retraining the discrimination after initial extinction and then conducting extinction again (i.e., re-extinction) with bupropion would affect responding. We found that bupropion (20 and 30 mg/kg) fully substituted for the nicotine stimulus in repeated 20-min extinction sessions. The extent of substitution in extinction did not necessarily predict performance in the transfer test (e.g., nicotine responding unchanged after extinction with 20 mg/kg bupropion). Generalization of extinction back to nicotine was not seen with 20 mg/kg bupropion even after increasing the number of extinction session from 6 to 24. Finally, there was evidence that learning in the initial extinction phase was retained in the re-extinction phase for nicotine and bupropion. These findings indicate that learning involving the nicotine stimuli are complex and that assessment approach for stimulus similarity changes conclusions regarding substitution by bupropion. Further research will be needed to identify whether such differences may be related to different facets of nicotine dependence and/or its treatment. PMID:25080073

  5. Panel Session

    DEFF Research Database (Denmark)

    Bertelsen, Olav Wedege

    2004-01-01

    In this panel session, four researchers will discuss the role of a theoretical foundation, in particular AT, in the design of information technology based artefacts. The general discussion will take of from a specific examination of the ActAD approach.......In this panel session, four researchers will discuss the role of a theoretical foundation, in particular AT, in the design of information technology based artefacts. The general discussion will take of from a specific examination of the ActAD approach....

  6. Breakout Sessions

    CERN Multimedia

    CERN. Geneva

    2004-01-01

    Participants are split into small groups for detailed discussion on their chosen topic. To register please click on 'See details' link from the agenda and then on the link to send an email to the session for which you would like to book. Please don't change the subject line of the email.

  7. Interstellar Extinction

    OpenAIRE

    Gontcharov, George

    2017-01-01

    This review describes our current understanding of interstellar extinction. This differ substantially from the ideas of the 20th century. With infrared surveys of hundreds of millions of stars over the entire sky, such as 2MASS, SPITZER-IRAC, and WISE, we have looked at the densest and most rarefied regions of the interstellar medium at distances of a few kpc from the sun. Observations at infrared and microwave wavelengths, where the bulk of the interstellar dust absorbs and radiates, have br...

  8. Session summaries

    International Nuclear Information System (INIS)

    Sudo, Y.

    2002-01-01

    In the summary session, possible international activities in the field of basic studies on high-temperature engineering were discussed within the framework of the OECD/NEA Nuclear Science Committee (NSC). It was recommended to include topics relevant to fission-product behaviour and safety issues of HTGR in next meeting, in addition to the topics discussed in this meeting. The chairperson of the last session summarised the recommendations to be presented to the NSC into the following five topics as possible international activities: - Basic studies on behaviour of irradiated graphite/carbon and ceramic materials including their composites under both operation and storage conditions. - Development of in-core material characterisation and instrumentation methods. - Improvement in material properties through high-temperature irradiation. - Basic studies on HTGR fuel fabrication and performance including fission-product release. - Basic studies on safety issues of HTGR. It was also recommended that a further information exchange meeting focused on the organisation of the interactive collaboration activity with regard to the above topics be planned in 2003, tentatively in Oarai, Japan. (author)

  9. Impossible Extinction

    Science.gov (United States)

    Cockell, Charles S.

    2003-03-01

    Every 225 million years the Earth, and all the life on it, completes one revolution around the Milky Way Galaxy. During this remarkable journey, life is influenced by calamitous changes. Comets and asteroids strike the surface of the Earth, stars explode, enormous volcanoes erupt, and, more recently, humans litter the planet with waste. Many animals and plants become extinct during the voyage, but humble microbes, simple creatures made of a single cell, survive this journey. This book takes a tour of the microbial world, from the coldest and deepest places on Earth to the hottest and highest, and witnesses some of the most catastrophic events that life can face. Impossible Extinction tells this remarkable story to the general reader by explaining how microbes have survived on Earth for over three billion years. Charles Cockell received his doctorate from the University of Oxford, and is currently a microbiologist with rhe Search for Extraterrestrial Intelligence Institute (SETI), based at the British Antarctic Survey in Cambridge, UK. His research focusses on astrobiology, life in the extremes and the human exploration of Mars. Cockell has been on expeditions to the Arctic, Antarctic, Mongolia, and in 1993 he piloted a modified insect-collecting ultra-light aircraft over the Indonesian rainforests. He is Chair of the Twenty-one Eleven Foundation for Exploration, a charity that supports expeditions that forge links between space exploration and environmentalism.

  10. Dopamine D1 receptor agonist treatment attenuates extinction of morphine conditioned place preference while increasing dendritic complexity in the nucleus accumbens core.

    Science.gov (United States)

    Kobrin, Kendra L; Arena, Danielle T; Heinrichs, Stephen C; Nguyen, Olivia H; Kaplan, Gary B

    2017-03-30

    The dopamine D1 receptor (D1R) has a role in opioid reward and conditioned place preference (CPP), but its role in CPP extinction is undetermined. We examined the effect of D1R agonist SKF81297 on the extinction of opioid CPP and associated dendritic morphology in the nucleus accumbens (NAc), a region involved with reward integration and its extinction. During the acquisition of morphine CPP, mice received morphine and saline on alternate days; injections were given immediately before each of eight daily conditioning sessions. Mice subsequently underwent six days of extinction training designed to diminish the previously learned association. Mice were treated with either 0.5mg/kg SKF81297, 0.8mg/kg SKF81297, or saline immediately after each extinction session. There was a dose-dependent effect, with the highest dose of SKF81297 attenuating extinction, as mice treated with this dose had significantly higher CPP scores than controls. Analysis of medium spiny neuron morphology revealed that in the NAc core, but not in the shell, dendritic arbors were significantly more complex in the morphine conditioned, SKF81297-treated mice compared to controls. In separate experiments using mice conditioned with only saline, SKF81297 administration after extinction sessions had no effect on CPP and produced differing effects on dendritic morphology. At the doses used in our experiments, SKF81297 appears to maintain previously learned opioid conditioned behavior, even in the face of new information. The D1R agonist's differential, rather than unidirectional, effects on dendritic morphology in the NAc core suggests that it may be involved in encoding reward information depending on previously learned behavior. Published by Elsevier B.V.

  11. Seasonal atmospheric extinction

    International Nuclear Information System (INIS)

    Mikhail, J.S.

    1979-01-01

    Mean monochromatic extinction coefficients at various wavelengths at the Kottamia Observatory site have shown the existence of a seasonal variation of atmospheric extinction. The extinction of aerosol compontnts with wavelengths at winter represent exceedingly good conditions. Spring gives the highest extinction due to aerosol. (orig.)

  12. BILATERAL SINGLE SESSION URETEROSCOPY FOR URETERAL ...

    African Journals Online (AJOL)

    Objectives: To determine the feasibility, safety and success rate of bilateral single session rigid retrograde ureteroscopy (URS) for bilateral ureteral calculi. Patients and Methods: Thirty-five patients underwent bilateral single session ureteroscopic calculus removal. Results: Out of 70 renal units in 35 patients treated, ...

  13. Modeling galactic extinction

    OpenAIRE

    Cecchi-Pestellini, C.; Mulas, G.; Casu, S.; Iatì, M. A.; Saija, R.; Cacciola, A.; Borghese, F.; Denti, P.

    2011-01-01

    We present a model for interstellar extinction dust, in which we assume a bimodal distribution of extinction carriers, a dispersion of core-mantle grains, supplemented by a collection of PAHs in free molecular form. We use state-of-the-art methods to calculate the extinction due to macroscopic dust particles, and the absorption cross-sections of PAHs in four different charge states. While successfull for most of observed Galactic extinction curves, in few cases the model cannot provide reliab...

  14. Gradual extinction reduces Reinstatement

    Directory of Open Access Journals (Sweden)

    Youssef eShiban

    2015-09-01

    Full Text Available The current study investigated whether gradually reducing the frequency of aversive stimuli during extinction can prevent the return of fear. Thirty-one participants of a three-stage procedure (acquisition, extinction and a reinstatement test on day two were randomly assigned to a standard extinction (SE and gradual extinction (GE procedure. The two groups differed only in the extinction procedure. While the SE group ran through a regular extinction process without any negative events, the frequency of the aversive stimuli during the extinction phase was gradually reduced for the GE group. The unconditioned stimulus was an air blast (5 bar, 10 ms. A spider and a scorpion were used as conditioned stimuli. The outcome variables were contingency ratings and physiological measures (skin conductance response and startle response. There were no differences found between the two groups for the acquisition and extinction phases concerning contingency ratings, SCR, or startle response. Gradual extinction compared to standard extinction significantly reduced the return of fear in the reinstatement test for the startle response but not for skin conductance response or contingency ratings. This study was successful in translating the findings in rodent to humans. The results suggest that the gradual extinction process is suitable for increasing the efficacy of fear extinction.

  15. [Inter-session-processes].

    Science.gov (United States)

    Zeeck, Almut; Hartmann, Armin; Orlinsky, David

    2004-06-01

    We do not know much about how patients internalize, remember or use psychotherapeutic experiences between psychotherapy sessions and how they use them for change. What happens with in-session-experiences after a session ("inter-session-process") is of main importance for outcome. The inter-session-process describes the work on psychotherapy between sessions. Although inter-session-processes are a central element connecting psychotherapy process and outcome, they remain a neglected area of research. Previous studies examined individual outpatient settings only. This paper gives an overview over theory, instruments for measurement, previous studies and relevance of inter-session-processes for the field of psychotherapy research.

  16. Modern examples of extinctions

    DEFF Research Database (Denmark)

    Lövei, Gabor L

    2013-01-01

    No species lives forever, and extinction is the ultimate fate of all living species. The fossil record indicates that a recent extinction wave affecting terrestrial vertebrates was parallel with the arrival of modern humans to areas formerly uninhabited by them. These modern instances of extinction......, by the time it has run its course, it will potentially surpass the previous five mass extinction events in the history of Earth. This article only deals with examples of extinction in the Quaternary period (from the final period of the last Ice Age, 10,000 years ago)....

  17. Bimodal extinction without cross-modal extinction.

    OpenAIRE

    Inhoff, A W; Rafal, R D; Posner, M J

    1992-01-01

    Three patients with unilateral neurological injury were clinically examined. All showed consistent unilateral extinction in the tactile and visual modalities on simultaneous intramodal stimulation. There was virtually no evidence for cross-modal extinction, however, so that contralateral stimulation of one modality would have extinguished perception of ipsilateral stimuli in the other modality. It is concluded that the attentional system controlling the encoding of tactile and visual stimuli ...

  18. Behavioral and neural bases of extinction learning in Hermissenda

    Science.gov (United States)

    Cavallo, Joel S.; Hamilton, Brittany N.; Farley, Joseph

    2014-01-01

    Extinction of classical conditioning is thought to produce new learning that masks or interferes with the original memory. However, research in the nudibranch Hermissenda crassicornis (H.c.) has challenged this view, and instead suggested that extinction erased the original associative memory. We have re-examined extinction in H.c. to test whether extinguished associative memories can be detected on the behavioral and cellular levels, and to characterize the temporal variables involved. Associative conditioning using pairings of light (CS) and rotation (US) produced characteristic suppression of H.c. phototactic behavior. A single session of extinction training (repeated light-alone presentations) reversed suppressed behavior back to pre-training levels when administered 15 min after associative conditioning. This effect was abolished if extinction was delayed by 23 h, and yet was recovered using extended extinction training (three consecutive daily extinction sessions). Extinguished phototactic suppression did not spontaneously recover at any retention interval (RI) tested (2-, 24-, 48-, 72-h), or after additional US presentations (no observed reinstatement). Extinction training (single session, 15 min interval) also reversed the pairing-produced increases in light-evoked spike frequencies of Type B photoreceptors, an identified site of associative memory storage that is causally related to phototactic suppression. These results suggest that the behavioral effects of extinction training are not due to temporary suppression of associative memories, but instead represent a reversal of the underlying cellular changes necessary for the expression of learning. In the companion article, we further elucidate mechanisms responsible for extinction-produced reversal of memory-related neural plasticity in Type B photoreceptors. PMID:25191236

  19. Behavioral and neural bases of extinction learning in Hermissenda

    Directory of Open Access Journals (Sweden)

    Joel S. Cavallo

    2014-08-01

    Full Text Available Extinction of classical conditioning is thought to produce new learning that masks or interferes with the original memory. However, research in the nudibranch Hermissenda crassicornis (H.c. has challenged this view, and instead suggested that extinction erased the original associative memory. We have re-examined extinction in H.c. to test whether extinguished associative memories can be detected on the behavioral and cellular levels, and to characterize the temporal variables involved. Associative conditioning using pairings of light (CS and rotation (US produced characteristic suppression of H.c. phototactic behavior. A single session of extinction training (repeated light-alone presentations reversed suppressed behavior back to pre-training levels when administered 15 min after associative conditioning. This effect was abolished if extinction was delayed by 23 hr, and yet was recovered using extended extinction training (three consecutive daily extinction sessions. Extinguished phototactic suppression did not spontaneously recover at any retention interval tested (2-, 24-, 48-, 72-hr, or after additional US presentations (no observed reinstatement. Extinction training (single session, 15 min interval also reversed the pairing-produced increases in light-evoked spike frequencies of Type B photoreceptors, an identified site of associative memory storage that is causally related to phototactic suppression. These results suggest that the behavioral effects of extinction training are not due to temporary suppression of associative memories, but instead represent a reversal of the underlying cellular changes necessary for the expression of learning. In the companion article, we further elucidate mechanisms responsible for extinction-produced reversal of memory-related neural plasticity in Type B photoreceptors.

  20. Extinction of Cocaine Seeking Requires a Window of Infralimbic Pyramidal Neuron Activity after Unreinforced Lever Presses.

    Science.gov (United States)

    Gutman, Andrea L; Nett, Kelle E; Cosme, Caitlin V; Worth, Wensday R; Gupta, Subhash C; Wemmie, John A; LaLumiere, Ryan T

    2017-06-21

    The infralimbic cortex (IL) mediates extinction learning and the active suppression of cocaine-seeking behavior. However, the precise temporal relationship among IL activity, lever pressing, and extinction learning is unclear. To address this issue, we used activity-guided optogenetics in male Sprague Dawley rats to silence IL pyramidal neurons optically for 20 s immediately after unreinforced lever presses during early extinction training after cocaine self-administration. Optical inhibition of the IL increased active lever pressing during shortened extinction sessions, but did not alter the retention of the extinction learning as assessed in ensuing extinction sessions with no optical inhibition. During subsequent cued reinstatement sessions, rats that had previously received optical inhibition during the extinction sessions showed increased cocaine-seeking behavior. These findings appeared to be specific to inhibition during the post-lever press period because IL inhibition given in a noncontingent, pseudorandom manner during extinction sessions did not produce the same effects. Illumination alone (i.e., with no opsin expression) and food-seeking control experiments also failed to produce the same effects. In another experiment, IL inhibition after lever presses during cued reinstatement sessions increased cocaine seeking during those sessions. Finally, inhibition of the prelimbic cortex immediately after unreinforced lever presses during shortened extinction sessions decreased lever pressing during these sessions, but had no effect on subsequent reinstatement. These results indicate that IL activity immediately after unreinforced lever presses is necessary for normal extinction of cocaine seeking, suggesting that critical encoding of the new contingencies between a lever press and a cocaine reward occurs during that period. SIGNIFICANCE STATEMENT The infralimbic cortex (IL) contributes to the extinction of cocaine-seeking behavior, but the precise relationship

  1. Extinction learning, which consists of the inhibition of retrieval, can be learned without retrieval.

    Science.gov (United States)

    de Carvalho Myskiw, Jociane; Furini, Cristiane Regina Guerino; Schmidt, Bianca; Ferreira, Flávia; Izquierdo, Ivan

    2015-01-13

    In the present study we test the hypothesis that extinction is not a consequence of retrieval in unreinforced conditioned stimulus (CS) presentation but the mere perception of the CS in the absence of a conditioned response. Animals with cannulae implanted in the CA1 region of hippocampus were subjected to extinction of contextual fear conditioning. Muscimol infused intra-CA1 before an extinction training session of contextual fear conditioning (CFC) blocks retrieval but not consolidation of extinction measured 24 h later. Additionally, this inhibition of retrieval does not affect early persistence of extinction when tested 7 d later or its spontaneous recovery after 2 wk. Furthermore, both anisomycin, an inhibitor of ribosomal protein synthesis, and rapamycin, an inhibitor of extraribosomal protein synthesis, given into the CA1, impair extinction of CFC regardless of whether its retrieval was blocked by muscimol. Therefore, retrieval performance in the first unreinforced session is not necessary for the installation, maintenance, or spontaneous recovery of extinction of CFC.

  2. Extinction with multiple excitors

    OpenAIRE

    McConnell, Bridget L.; Miguez, Gonzalo; Miller, Ralph R.

    2013-01-01

    Four conditioned suppression experiments with rats, using an ABC renewal design, investigated the effects of compounding the target conditioned excitor with additional, nontarget conditioned excitors during extinction. Experiment 1 showed stronger extinction, as evidenced by less renewal, when the target excitor was extinguished in compound with a second excitor, relative to when it was extinguished with associatively neutral stimuli. Critically, this deepened extinction effect was attenuated...

  3. Opposing effects of D-cycloserine on fear despite a common extinction duration: interactions between brain regions and behavior.

    Science.gov (United States)

    Bolkan, Scott S; Lattal, K Matthew

    2014-09-01

    A number of studies have reported that D-cycloserine (DCS), a partial agonist of the N-methyl-D-aspartate glutamate receptor, can facilitate the loss of conditioned fear if it is administered during an extinction trial. Here we examine the effects of DCS injected into the hippocampus or amygdala on extinction of context-evoked freezing after contextual fear conditioning in C57BL/6 mice. We find that DCS administered prior to an extinction session decreased freezing from the outset of the session regardless of which brain region was targeted. Retention tests revealed opposite effects on fear expression despite identical behavioral treatments: intra-hippocampal DCS inhibited fear expression while intra-amygdala DCS potentiated fear expression. Following post-extinction session injections of DCS, we found a similar though less pronounced effect. Closer inspection of the data revealed that the effects of DCS interacted with the behavior of the subjects during extinction. Intra-hippocampal injections of DCS enhanced extinction in those mice that showed the greatest amount of within-session extinction, but had less pronounced effects on mice that showed the least within-session extinction. Intra-amygdala injections of DCS impaired extinction in those mice that showed the least within-session extinction, but there was some evidence that the effect in the amygdala did not depend on behavior during extinction. These findings demonstrate that even with identical extinction trial durations, the effects of DCS administered into the hippocampus and amygdala can heavily depend on the organism's behavior during the extinction session. The broader implication of these findings is that the effects of pharmacological treatments designed to enhance extinction by targeting hippocampal or amygdalar processes may depend on the responsivity of the subject to the behavioral treatment. Copyright © 2013 Elsevier Inc. All rights reserved.

  4. Mass extinction: a commentary

    Science.gov (United States)

    Raup, D. M.

    1987-01-01

    Four neocatastrophist claims about mass extinction are currently being debated; they are that: 1, the late Cretaceous mass extinction was caused by large body impact; 2, as many as five other major extinctions were caused by impact; 3, the timing of extinction events since the Permian is uniformly periodic; and 4, the ages of impact craters on Earth are also periodic and in phase with the extinctions. Although strongly interconnected the four claims are independent in the sense that none depends on the others. Evidence for a link between impact and extinction is strong but still needs more confirmation through bed-by-bed and laboratory studies. An important area for future research is the question of whether extinction is a continuous process, with the rate increasing at times of mass extinctions, or whether it is episodic at all scales. If the latter is shown to be generally true, then species are at risk of extinction only rarely during their existence and catastrophism, in the sense of isolated events of extreme stress, is indicated. This is line of reasoning can only be considered an hypothesis for testing. In a larger context, paleontologists may benefit from a research strategy that looks to known Solar System and Galactic phenomena for predictions about environmental effects on earth. The recent success in the recognition of Milankovitch Cycles in the late Pleistocene record is an example of the potential of this research area.

  5. End Ordovician extinctions

    DEFF Research Database (Denmark)

    Harper, David Alexander Taylor; Hammarlund, Emma U.; Rasmussen, Christian Mac Ørum

    2014-01-01

    -global anoxia associated with a marked transgression during the Late Hirnantian. Most recently, however, new drivers for the extinctions have been proposed, including widespread euxinia together with habitat destruction caused by plate tectonic movements, suggesting that the end Ordovician mass extinctions were...

  6. Extinction of NGC 7027

    International Nuclear Information System (INIS)

    Seaton, M.J.

    1979-01-01

    Emission intensities of recombination lines in hydrogenic spectra are known accurately relative to intensities in the free-free radio continuum. For NGC 7027 intensities have been measured for the radio continuum and for H I and He II lines in the wavelength range from lambda = 2.17 μm to lambda = 1640 A: comparison with the calculated emission intensities gives the extinction. Determinations of the standard interstellar extinction function are critically discussed. The extinction deduced for the total radiation from NGC 7027 has a dependence on wavelength for 6563 A >= lambda >= 1640 A which is in excellent agreement with the adopted standard results, but there are some anomalies for longer wavelengths and for the ratio of total to selective extinction. These can be explained using a model which allows for a local contribution to the extinction which is variable over the surface of the nebula. (author)

  7. Interstellar extinction correlations

    International Nuclear Information System (INIS)

    Jones, A.P.; Williams, D.A.; Duley, W.W.

    1987-01-01

    A recently proposed model for interstellar grains in which the extinction arises from small silicate cores with mantles of hydrogenated amorphous carbon (HAC or α-C:H), and large, but thinly coated, silicate grains can successfully explain many of the observed properties of interstellar dust. The small silicate cores give rise to the 2200 A extinction feature. The extinction in the visual is produced by the large silicates and the HAC mantles on the small cores, whilst the far UV extinction arises in the HAC mantles with a small contribution form the silicate grains. The grain model requires that the silicate material is the more resilient component and that variations in the observed extinction from region to region are due to the nature and depletion of the carbon in the HAC mantles. (author)

  8. Extinction and the fossil record

    Science.gov (United States)

    Sepkoski, J. J. Jr; Sepkoski JJ, ,. J. r. (Principal Investigator)

    1994-01-01

    The author examines evidence of mass extinctions in the fossil record and searches for reasons for such large extinctions. Five major mass extinctions eliminated at least 40 percent of animal genera in the oceans and from 65 to 95 percent of ocean species. Questions include the occurrence of gradual or catastrophic extinctions, causes, environment, the capacity of a perturbation to cause extinctions each time it happens, and the possibility and identification of complex events leading to a mass extinction.

  9. Is IR going extinct?

    Science.gov (United States)

    Mitchell, Audra

    2016-01-01

    A global extinction crisis may threaten the survival of most existing life forms. Influential discourses of ‘existential risk’ suggest that human extinction is a real possibility, while several decades of evidence from conservation biology suggests that the Earth may be entering a ‘sixth mass extinction event’. These conditions threaten the possibilities of survival and security that are central to most branches of International Relations. However, this discipline lacks a framework for addressing (mass) extinction. From notions of ‘nuclear winter’ and ‘omnicide’ to contemporary discourses on catastrophe, International Relations thinking has treated extinction as a superlative of death. This is a profound category mistake: extinction needs to be understood not in the ontic terms of life and death, but rather in the ontological context of be(com)ing and negation. Drawing on the work of theorists of the ‘inhuman’ such as Quentin Meillassoux, Claire Colebrook, Ray Brassier, Jean-Francois Lyotard and Nigel Clark, this article provides a pathway for thinking beyond existing horizons of survival and imagines a profound transformation of International Relations. Specifically, it outlines a mode of cosmopolitics that responds to the element of the inhuman and the forces of extinction. Rather than capitulating to narratives of tragedy, this cosmopolitics would make it possible to think beyond the restrictions of existing norms of ‘humanity’ to embrace an ethics of gratitude and to welcome the possibility of new worlds, even in the face of finitude.

  10. Temporal Dynamics of Recovery from Extinction Shortly after Extinction Acquisition

    Science.gov (United States)

    Archbold, Georgina E.; Dobbek, Nick; Nader, Karim

    2013-01-01

    Evidence suggests that extinction is new learning. Memory acquisition involves both short-term memory (STM) and long-term memory (LTM) components; however, few studies have examined early phases of extinction retention. Retention of auditory fear extinction was examined at various time points. Shortly (1-4 h) after extinction acquisition…

  11. Brain activation during fear extinction predicts exposure success.

    Science.gov (United States)

    Ball, Tali Manber; Knapp, Sarah E; Paulus, Martin P; Stein, Murray B

    2017-03-01

    Exposure therapy, a gold-standard treatment for anxiety disorders, is assumed to work via extinction learning, but this has never been tested. Anxious individuals demonstrate extinction learning deficits, likely related to less ventromedial prefrontal cortex (vmPFC) and more amygdala activation, but the relationship between these deficits and exposure outcome is unknown. We tested whether anxious individuals who demonstrate better extinction learning report greater anxiety reduction following brief exposure. Twenty-four adults with public speaking anxiety completed (1) functional magnetic resonance imaging during a conditioning paradigm, (2) a speech exposure session, and (3) anxiety questionnaires before and two weeks postexposure. Extinction learning was assessed by comparing ratings to a conditioned stimulus (neutral image) that was previously paired with an aversive noise against a stimulus that had never been paired. Robust regression analyses examined whether brain activation during extinction learning predicted anxiety reduction two weeks postexposure. On average, the conditioning paradigm resulted in acquisition and extinction effects on stimulus ratings, and the exposure session resulted in reduced anxiety two weeks post-exposure. Consistent with our hypothesis, individuals with better extinction learning (less negative stimulus ratings), greater activation in vmPFC, and less activation in amygdala, insula, and periaqueductal gray reported greater anxiety reduction two weeks postexposure. To our knowledge, this is the first time that the theoretical link between extinction learning and exposure outcome has been demonstrated. Future work should examine whether extinction learning can be used as a prognostic test to determine who is most likely to benefit from exposure therapy. © 2016 Wiley Periodicals, Inc.

  12. Effects of reinforcement schedule on facilitation of operant extinction by chlordiazepoxide.

    Science.gov (United States)

    Leslie, Julian C; Shaw, David; Gregg, Gillian; McCormick, Nichola; Reynolds, David S; Dawson, Gerard R

    2005-11-01

    Learning and memory are central topics in behavioral neuroscience, and inbred mice strains are widely investigated. However, operant conditioning techniques are not as extensively used in this field as they should be, given the effectiveness of the methodology of the experimental analysis of behavior. In the present study, male C57B1/6 mice, widely used as background for transgenic studies, were trained to lever press on discrete-trial fixed-ratio 5 or fixed-interval (11 s or 31 s) schedules of food reinforcement and then exposed to 15 extinction sessions following vehicle or chlordiazepoxide injections (15 mg/kg i.p., administered either prior to all extinction sessions, or prior to the final 10 extinction sessions). Extinction of operant behavior was facilitated by drug administration following training on either schedule, but this facilitation only occurred once a number of extinction sessions had taken place. The extinction process proceeded more rapidly following fixed-interval training. Resistance to extinction was equally high following training with either schedule type, and was reduced by drug administration in both cases. These phenomena were evident in individual cumulative records and in analyses of group data. Results are interpreted in terms of phenomena of operant extinction identified in Skinner's (1938) Behavior of Organisms, and by behavioral momentum theory. These procedures could be used to extend the contribution of operant conditioning to contemporary behavioral neuroscience.

  13. Blockade of Dopamine Activity in the Nucleus Accumbens Impairs Learning Extinction of Conditioned Fear

    Science.gov (United States)

    Holtzman-Assif, Orit; Laurent, Vincent; Westbrook, R. Frederick

    2010-01-01

    Three experiments used rats to investigate the role of dopamine activity in learning to inhibit conditioned fear responses (freezing) in extinction. In Experiment 1, rats systemically injected with the D2 dopamine antagonist, haloperidol, froze more across multiple extinction sessions and on a drug-free retention test than control rats. In…

  14. Reexposure to the Amnestic Agent Alleviates Cycloheximide-Induced Retrograde Amnesia for Reactivated and Extinction Memories

    Science.gov (United States)

    Briggs, James F.; Olson, Brian P.

    2013-01-01

    We investigated whether reexposure to an amnestic agent would reverse amnesia for extinction of learned fear similar to that of a reactivated memory. When cycloheximide (CHX) was administered immediately after a brief cue-induced memory reactivation (15 sec) and an extended extinction session (12 min) rats showed retrograde amnesia for both…

  15. The Extinction and Return of Fear of Public Speaking.

    Science.gov (United States)

    Laborda, Mario A; Schofield, Casey A; Johnson, Emily M; Schubert, Jessica R; George-Denn, Daniel; Coles, Meredith E; Miller, Ralph R

    2016-11-01

    Prior studies indicate extinguished fear often partially returns when participants are later tested outside the extinction context. Cues carried from the extinction context to the test context sometimes reduce return of fear, but it is unclear whether such extinction cues (ECs) reduce return of fear of public speaking. Here we assessed return of fear of public speaking, and whether either of two types of ECs can attenuate it. Participants gave speeches of increasing difficulty during an exposure practice session and were tested 2 days later in a different context. Testing occurred in the presence of physical ECs, after mentally rehearsing the exposure session, or without either reminder. Practice reduced fear of public speaking, but fear partially returned at test. Neither physical nor mental ECs reduced partial return of fear of public speaking. The return of extinguished fear of public speaking, although small, was reliable, but not appreciably sensitive to presence of ECs. © The Author(s) 2016.

  16. A case that underwent bilateral video-assisted thoracoscopic ...

    African Journals Online (AJOL)

    No Abstract Available A case that underwent bilateral video-assisted thoracoscopic surgical (VATS) biopsy combined with pneumonectomy is presented. The patient developed hypoxia during the contralateral VATS biopsy. His hypoxia was treated with positive expiratory pressure (PEEP) to the dependent lung and apneic ...

  17. No impact of repeated extinction exposures on operant responding maintained by different reinforcer rates.

    Science.gov (United States)

    Bai, John Y H; Podlesnik, Christopher A

    2017-05-01

    Greater rates of intermittent reinforcement in the presence of discriminative stimuli generally produce greater resistance to extinction, consistent with predictions of behavioral momentum theory. Other studies reveal more rapid extinction with higher rates of reinforcers - the partial reinforcement extinction effect. Further, repeated extinction often produces more rapid decreases in operant responding due to learning a discrimination between training and extinction contingencies. The present study examined extinction repeatedly with training with different rates of intermittent reinforcement in a multiple schedule. We assessed whether repeated extinction would reverse the pattern of greater resistance to extinction with greater reinforcer rates. Counter to this prediction, resistance to extinction was consistently greater across twelve assessments of training followed by six successive sessions of extinction. Moreover, patterns of responding during extinction resembled those observed during satiation tests, which should not alter discrimination processes with repeated testing. These findings join others suggesting operant responding in extinction can be durable across repeated tests. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Stress and Fear Extinction

    Science.gov (United States)

    Maren, Stephen; Holmes, Andrew

    2016-01-01

    Stress has a critical role in the development and expression of many psychiatric disorders, and is a defining feature of posttraumatic stress disorder (PTSD). Stress also limits the efficacy of behavioral therapies aimed at limiting pathological fear, such as exposure therapy. Here we examine emerging evidence that stress impairs recovery from trauma by impairing fear extinction, a form of learning thought to underlie the suppression of trauma-related fear memories. We describe the major structural and functional abnormalities in brain regions that are particularly vulnerable to stress, including the amygdala, prefrontal cortex, and hippocampus, which may underlie stress-induced impairments in extinction. We also discuss some of the stress-induced neurochemical and molecular alterations in these brain regions that are associated with extinction deficits, and the potential for targeting these changes to prevent or reverse impaired extinction. A better understanding of the neurobiological basis of stress effects on extinction promises to yield novel approaches to improving therapeutic outcomes for PTSD and other anxiety and trauma-related disorders. PMID:26105142

  19. Biological extinction in earth history

    Science.gov (United States)

    Raup, D. M.

    1986-01-01

    Virtually all plant and animal species that have ever lived on the earth are extinct. For this reason alone, extinction must play an important role in the evolution of life. The five largest mass extinctions of the past 600 million years are of greatest interest, but there is also a spectrum of smaller events, many of which indicate biological systems in profound stress. Extinction may be episodic at all scales, with relatively long periods of stability alternating with short-lived extinction events. Most extinction episodes are biologically selective, and further analysis of the victims and survivors offers the greatest chance of deducing the proximal causes of extinction. A drop in sea level and climatic change are most frequently invoked to explain mass extinctions, but new theories of collisions with extraterrestrial bodies are gaining favor. Extinction may be constructive in a Darwinian sense or it may only perturb the system by eliminating those organisms that happen to be susceptible to geologically rare stresses.

  20. Dopamine in the nucleus accumbens core, but not shell, increases during signaled food reward and decreases during delayed extinction.

    Science.gov (United States)

    Biesdorf, C; Wang, A-L; Topic, B; Petri, D; Milani, H; Huston, J P; de Souza Silva, M A

    2015-09-01

    Microdialysis studies in rat have generally shown that appetitive stimuli release dopamine (DA) in the nucleus accumbens (NAc) shell and core. Here we examined the release of DA in the NAc during delivery of reward (food) and during extinction of food reward in the freely moving animal by use of in vivo microdialysis and HPLC. Fifty-two male Wistar rats were trained to receive food reward associated with appearance of cue-lights in a Skinner-box during in vivo microdialysis. Different behavioral protocols were used to assess the effects of extinction on DA and its metabolites. Results Exp. 1: (a) During a 20-min period of cued reward delivery, DA increased significantly in the NAc core, but not shell subregion; (b) for the next 60min period half of the rats underwent immediate extinction (with the CS light presented during non-reward) and the other half did not undergo extinction to the cue lights (CS was not presented during non-reward). DA remained significantly increased in both groups, providing no evidence for a decrease in DA during extinction in either NAc core or shell regions. (c) In half of the animals of the group that was not subjected to extinction, the cue lights were turned on for 30min, thus, initiating extinction to cue CS at a 1h delay from the period of reward. In this group DA in the NAc core, but not shell, significantly decreased. Behavioral analysis showed that while grooming is an indicator of extinction-induced behavior, glances toward the cue-lights (sign tracking) are an index of resistance to extinction. Results Exp. 2: (a) As in Exp. 1, during a 30-min period of cued reward delivery, DA levels again increased significantly in the NAc core but not in the NAc shell. (b) When extinction (the absence of reward with the cue lights presented) was administered 24h after the last reward session, DA again significantly decreased in the NAc core, but not in the NAc shell. (a) These results confirm the importance of DA release in the NAc for

  1. Post-Session Authentication

    DEFF Research Database (Denmark)

    Ahmed, Naveed; Jensen, Christian D.

    2012-01-01

    Entity authentication provides confidence in the claimed identity of a peer entity, but the manner in which this goal is achieved results in different types of authentication. An important factor in this regard is the order between authentication and the execution of the associated session. In th...... as the only setup assumption. We hope post-session authentication can be used to devise new strategies for building trust among strangers....

  2. NUTRITION SUPPORT COMPLICATIONS IN PATIENT WHO UNDERWENT CARDIAC SURGERY

    OpenAIRE

    Krdžalić, Alisa; Kovčić, Jasmina; Krdžalić, Goran; Jahić, Elmir

    2016-01-01

    Background: The nutrition support complications after cardiac surgery should be detected and treated on time. Aim: To show the incidence and type of nutritional support complication in patients after cardiac surgery. Methods: The prospective study included 415 patients who underwent cardiac surgery between 2010 and 2013 in Clinic for Cardiovascular Disease of University Clinical Center Tuzla. Complications of the delivery system for nutrition support (NS) and nutrition itself were analy...

  3. Activation of orexin/hypocretin neurons is associated with individual differences in cued fear extinction.

    Science.gov (United States)

    Sharko, Amanda C; Fadel, Jim R; Kaigler, Kris F; Wilson, Marlene A

    2017-09-01

    Identifying the neurobiological mechanisms that underlie differential sensitivity to stress is critical for understanding the development and expression of stress-induced disorders, such as post-traumatic stress disorder (PTSD). Preclinical studies have suggested that rodents display different phenotypes associated with extinction of Pavlovian conditioned fear responses, with some rodent populations being resistant to extinction. An emerging literature also suggests a role for orexins in the consolidation processes associated with fear learning and extinction. To examine the possibility that the orexin system might be involved in individual differences in fear extinction, we used a Pavlovian conditioning paradigm in outbred Long-Evans rats. Rats showed significant variability in the extinction of cue-conditioned freezing and extinction recall, and animals were divided into groups based on their extinction profiles based on a median split of percent freezing behavior during repeated exposure to the conditioned cue. Animals resistant to extinction (high freezers) showed more freezing during repeated cue presentations during the within trial and between trial extinction sessions compared with the group showing significant extinction (low freezers), although there were no differences between these groups in freezing upon return to the conditioned context or during the conditioning session. Following the extinction recall session, activation of orexin neurons was determined using dual label immunohistochemistry for cFos in orexin positive neurons in the hypothalamus. Individual differences in the extinction of cue conditioned fear were associated with differential activation of hypothalamic orexin neurons. Animals showing poor extinction of cue-induced freezing (high freezers) had significantly greater percentage of orexin neurons with Fos in the medial hypothalamus than animals displaying significant extinction and good extinction recall (low freezers). Further, the

  4. Building physiological toughness: Some aversive events during extinction may attenuate return of fear.

    Science.gov (United States)

    Culver, Najwa C; Stevens, Stephan; Fanselow, Michael S; Craske, Michelle G

    2018-03-01

    Although exposure therapy is an effective treatment for anxiety disorders, fear sometimes returns following successful therapy. Recent literature in animal models indicates that incorporating some aversive events into extinction training may offset these return of fear effects. The effect of occasional reinforced extinction trials was investigated in a sample of thirty-nine participants using a fear conditioning and extinction paradigm. Participants either underwent traditional extinction procedures during which the conditional stimulus which had been paired with the unconditional stimulus (US) during acquisition training (CS+) was presented alone with no presentations of the US or partially reinforced extinction during which there were several unpredicted CS+/US pairings. As measured by skin conductance responses, physiological fear responding remained elevated during extinction for participants who experienced partially reinforced extinction; however, these participants demonstrated protection from rapid reacquisition effects. Results from the subjective US-expectancy ratings did not provide evidence of protection against rapid reacquisition in the partially reinforced extinction group; however, there was evidence of protection from spontaneous recovery effects. Lastly, as measured by valence ratings, it was unclear whether partially reinforced extinction provided protection from fear recovery effects. Although participants who experienced partially reinforced extinction demonstrated protection from rapid reacquisition as measured by skin conductance responses, they also demonstrated significantly higher levels of physiological fear responding during extinction which made the results of the spontaneous recovery test more difficult to interpret. Occasional CS-US pairings during extinction may protect against return of fear effects. Clinical implications are discussed. Published by Elsevier Ltd.

  5. Summary: Hadron dynamics sessions

    International Nuclear Information System (INIS)

    Carroll, A.S.; Londergan, J.T.

    1993-01-01

    Four sessions on Hadron Dynamics were organized at this Workshop. The first topic, QCD Exclusive Reactions and Color Transparency, featured talks by Ralston, Heppelman and Strikman; the second, QCD and Inclusive Reactions had talks by Garvey, Speth and Kisslinger. The third dynamics session, Medium Modification of Elementary Interactions had contributions from Kopeliovich, Alves and Gyulassy; the fourth session Pre-QCD Dynamics and Scattering, had talks by Harris, Myhrer and Brown. An additional joint Spectroscopy/Dynamics session featured talks by Zumbro, Johnson and McClelland. These contributions are reviewed briefly in this summary. Two additional joint sessions between Dynamics and η physics are reviewed by the organizers of the Eta sessions. In such a brief review there is no way the authors can adequately summarize the details of the physics presented here. As a result, they concentrate only on brief impressionistic sketches of the physics topics discussed and their interrelations. They include no bibliography in this summary, but simply refer to the talks given in more detail in the Workshop proceedings. They focus on topics which were common to several presentations in these sessions. First, nuclear and particle descriptions of phenomena are now clearly converging, in both a qualitative and quantitative sense; they show several examples of this convergence. Second, an important issue in hadron dynamics is the extent to which elementary interactions are modified in nuclei at high energies and/or densities, and they illustrate some of these medium effects. Finally, they focus on those dynamical issues where hadron facilities can make an important, or even a unique, contribution to the knowledge of particle and nuclear physics

  6. Summary: Hadron dynamics sessions

    Energy Technology Data Exchange (ETDEWEB)

    Carroll, A.S. [Brookhaven National Lab., Upton, NY (United States); Londergan, J.T. [Indiana Univ., Bloomington, IN (United States)

    1993-11-01

    Four sessions on Hadron Dynamics were organized at this Workshop. The first topic, QCD Exclusive Reactions and Color Transparency, featured talks by Ralston, Heppelman and Strikman; the second, QCD and Inclusive Reactions had talks by Garvey, Speth and Kisslinger. The third dynamics session, Medium Modification of Elementary Interactions had contributions from Kopeliovich, Alves and Gyulassy; the fourth session Pre-QCD Dynamics and Scattering, had talks by Harris, Myhrer and Brown. An additional joint Spectroscopy/Dynamics session featured talks by Zumbro, Johnson and McClelland. These contributions are reviewed briefly in this summary. Two additional joint sessions between Dynamics and {eta} physics are reviewed by the organizers of the Eta sessions. In such a brief review there is no way the authors can adequately summarize the details of the physics presented here. As a result, they concentrate only on brief impressionistic sketches of the physics topics discussed and their interrelations. They include no bibliography in this summary, but simply refer to the talks given in more detail in the Workshop proceedings. They focus on topics which were common to several presentations in these sessions. First, nuclear and particle descriptions of phenomena are now clearly converging, in both a qualitative and quantitative sense; they show several examples of this convergence. Second, an important issue in hadron dynamics is the extent to which elementary interactions are modified in nuclei at high energies and/or densities, and they illustrate some of these medium effects. Finally, they focus on those dynamical issues where hadron facilities can make an important, or even a unique, contribution to the knowledge of particle and nuclear physics.

  7. Extinction after fear memory reactivation fails to eliminate renewal in rats.

    Science.gov (United States)

    Goode, Travis D; Holloway-Erickson, Crystal M; Maren, Stephen

    2017-07-01

    Retrieving fear memories just prior to extinction has been reported to effectively erase fear memories and prevent fear relapse. The current study examined whether the type of retrieval procedure influences the ability of extinction to impair fear renewal, a form of relapse in which responding to a conditional stimulus (CS) returns outside of the extinction context. Rats first underwent Pavlovian fear conditioning with an auditory CS and footshock unconditional stimulus (US); freezing behavior served as the index of conditioned fear. Twenty-four hours later, the rats underwent a retrieval-extinction procedure. Specifically, 1h prior to extinction (45 CS-alone trials; 44 for rats receiving a CS reminder), fear memory was retrieved by either a single exposure to the CS alone, the US alone, a CS paired with the US, or exposure to the conditioning context itself. Over the next few days, conditional freezing to the extinguished CS was tested in the extinction and conditioning context in that order (i.e., an ABBA design). In the extinction context, rats that received a CS+US trial before extinction exhibited higher levels of conditional freezing than animals in all other groups, which did not differ from one another. In the renewal context, all groups showed renewal, and none of the reactivation procedures reduced renewal relative to a control group that did not receive a reactivation procedure prior to extinction. These data suggest retrieval-extinction procedures may have limited efficacy in preventing fear renewal. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Alterations in neuronal morphology in infralimbic cortex predict resistance to fear extinction following acute stress

    Directory of Open Access Journals (Sweden)

    Kelly M. Moench

    2016-06-01

    Full Text Available Dysfunction in corticolimbic circuits that mediate the extinction of learned fear responses is thought to underlie the perseveration of fear in stress-related psychopathologies, including post-traumatic stress disorder. Chronic stress produces dendritic hypertrophy in basolateral amygdala (BLA and dendritic hypotrophy in medial prefrontal cortex, whereas acute stress leads to hypotrophy in both BLA and prelimbic cortex. Additionally, both chronic and acute stress impair extinction retrieval. Here, we examined the effects of a single elevated platform stress on extinction learning and dendritic morphology in infralimbic cortex, a region considered to be critical for extinction. Acute stress produced resistance to extinction, as well as dendritic retraction in infralimbic cortex. Spine density on apical and basilar terminal branches was unaffected by stress. However, animals that underwent conditioning and extinction had decreased spine density on apical terminal branches. Thus, whereas dendritic morphology in infralimbic cortex appears to be particularly sensitive to stress, changes in spines may more sensitively reflect learning. Further, in stressed rats that underwent conditioning and extinction, the level of extinction learning was correlated with spine densities, in that rats with poorer extinction retrieval had more immature spines and fewer thin spines than rats with better extinction retrieval, suggesting that stress may have impaired learning-related spine plasticity. These results may have implications for understanding the role of medial prefrontal cortex in learning deficits associated with stress-related pathologies.

  9. The Age of Extinction

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 20; Issue 8. The Age of Extinction. Prasanna Venkhatesh V. Book Review Volume 20 Issue 8 August 2015 pp 748-750. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/020/08/0748-0750. Author Affiliations.

  10. Effects of muscarinic M1 and M4 acetylcholine receptor stimulation on extinction and reinstatement of cocaine seeking in male mice, independent of extinction learning.

    Science.gov (United States)

    Stoll, Kevin; Hart, Rachel; Lindsley, Craig W; Thomsen, Morgane

    2018-03-01

    Stimulating muscarinic M 1 /M 4 receptors can blunt reinforcing and other effects of cocaine. A hallmark of addiction is continued drug seeking/craving after abstinence and relapse. We tested whether stimulating M 1 and/or M 4 receptors could facilitate extinction of cocaine seeking, and whether this was mediated via memory consolidation. Experimentally naïve C57BL/6J mice were allowed to acquire self-administration of intravenous cocaine (1 mg/kg/infusion) under a fixed-ratio 1 schedule of reinforcement. Then, saline was substituted for cocaine until responding extinguished to ≤30% of cocaine-reinforced responding. Immediately after each extinction session, mice received saline, the M 1 /M 4 receptor-preferring agonist xanomeline, the M 1 receptor-selective allosteric agonist VU0357017, the M 4 receptor-selective positive allosteric modulator VU0152100, or VU0357017 + VU0152100. In additional experiments, xanomeline was administered delayed after the session or in the home cage before extinction training began. In the latter group, reinstatement of responding by a 10-mg/kg cocaine injection was also tested. Stimulating M 1  + M 4 receptors significantly expedited extinction from 17.2 sessions to 8.3 using xanomeline or 7.8 using VU0357017 + VU0152100. VU0357017 alone and VU0152100 alone did not significantly modify rates of extinction (12.6 and 14.6 sessions). The effect of xanomeline was fully preserved when administered delayed after or unpaired from extinction sessions (7.5 and 6.4 sessions). Xanomeline-treated mice showed no cocaine-induced reinstatement. These findings show that M 1 /M 4 receptor stimulation can decrease cocaine seeking in mice. The effect lasted beyond treatment duration and was not dependent upon extinction learning. This suggests that M 1 /M 4 receptor stimulation modulated or reversed some neurochemical effects of cocaine exposure.

  11. The effect of hippocampal NMDA receptor blockade by MK-801 on cued fear extinction.

    Science.gov (United States)

    Zhang, Bo; Li, Chuan-Yu; Wang, Xiu-Song

    2017-08-14

    Extinction of conditioned fear has been suggested to be a new form of learning instead of erasure of what was originally learned, and the process is NMDA (N-methyl d-aspartate) receptor (NMDAR) dependent. Most of studies have so far revealed the important roles of NMDARs in the amygdala and medial prefrontal cortex (mPFC) in cued fear extinction. Although the ventral hippocampus has intimately reciprocal connections with the amygdala and mPFC, the role of its NMDARs in cued fear extinction remains unclear. The present experiment explored the issue by bilateral pre-extinction microinjection of the noncompetitive NMDAR antagonist MK-801 into the ventral hippocampus. Four groups of rats were given habituation, tone cued fear conditioning, fear extinction training and extinction test. Prior to extinction training, rats received bilateral infusions of either MK-801 (1.5, 3, or 6μg/0.5μl) or saline. Our results showed that MK-801 reduced freezing on the first trial of extinction training with no impact on within-session acquisition of extinction, and that the lower doses of MK-801 resulted in increased freezing on the extinction retrieval test. These findings suggest that ventral hippocampal NMDARs are necessary for the consolidation of tone cued fear extinction. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Extinction learning as a moderator of d-cycloserine efficacy for enhancing exposure therapy in posttraumatic stress disorder.

    Science.gov (United States)

    de Kleine, Rianne A; Smits, Jasper A J; Hendriks, Gert-Jan; Becker, Eni S; van Minnen, Agnes

    2015-08-01

    Augmentation of exposure therapy with d-cycloserine (DCS) has proven efficacious across anxiety disorders, although results in PTSD have been mixed. Work in animals and anxiety-disordered patients suggest that the potentiating effects of DCS are dependent on the level of extinction learning during extinction training and exposure treatment, respectively. The aim of the current study was to replicate and extend previous work by examining the association between the degree of extinction learning and DCS efficacy in our randomized clinical trial on DCS (50 mg) versus placebo enhancement of exposure therapy in a chronic mixed-trauma PTSD sample (N=67; de Kleine, Hendriks, Kusters, Broekman, & van Minnen, 2012). The decline in subjective units of distress ratings collected during and across the exposure sessions were evaluated as indices of extinction learning. First, we examined whether extinction learning during an exposure session moderated DCS effects on self-reported PTSD symptoms at the next session. Second, we examined whether averaged extinction learning over the course of treatment interacted with group assignment to predict change over time and post treatment outcome. We did not find evidence that DCS effects were moderated by the degree of extinction learning, although, extinction learning was related to outcome regardless of group assignment. In PTSD, not one extinction-learning index has been consistently linked to DCS enhanced exposure treatment outcome. More (experimental) work needs to been done to unravel the complex interplay between extinction learning and DCS enhancement, especially in PTSD patients. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Session 2: Machine studies

    International Nuclear Information System (INIS)

    Assmann, R.W.; Papotti, G.

    2012-01-01

    This document summarizes the talks and discussion that took place in the second session of the Chamonix 2012 workshop concerning results from machine studies performed in 2011. The session consisted of the following presentations: -) LHC experience with different bunch spacings by G. Rumolo; -) Observations of beam-beam effects in MDs in 2011 by W. Herr; -) Beam-induced heating/ bunch length/RF and lessons for 2012 by E. Metral; -) Lessons in beam diagnostics by R. Jones; -) Quench margins by M. Sapinski; and -) First demonstration with beam of the Achromatic Telescopic Squeeze (ATS) by S. Fartoukh. (authors)

  14. Pigmented Villonodular Synovitis in a Patient who Underwent Hip Arthroplasty

    Directory of Open Access Journals (Sweden)

    Nevzat Dabak

    2014-09-01

    Full Text Available Pigmented villonodular synovitis (PVNS is a rare, benign, but a locally aggressive tumor. It is characterized by the proliferation of synovial membrane, but it can also be seen in tendon sheaths and bursae. Clinical presentation of solitary lesions include compression and locking of the joint suggesting loose bodies in the joint and a subsequent findings of an effusion, whereas diffuse lesions manifest with pain and chronic swelling. In this article, we presented a curious case of PVNS in a female patient who have been followed up due to an acetabular cystic lesion. She underwent total hip arthroplasty for severe osteoarthritis of the hip joint and associated pain. The diagnosis of PVNS was established intraoperatively. (The Me­di­cal Bul­le­tin of Ha­se­ki 2014; 52: 235-7

  15. ALGORITHM FOR MANAGEMENT OF HYPERTENSIVE PATIENTS UNDERWENT UROLOGY INTERVENTIONS

    Directory of Open Access Journals (Sweden)

    S. S. Davydova

    2015-09-01

    Full Text Available Aim. To study the efficacy of cardiovascular non-invasive complex assessment and pre-operative preparation in hypertensive patients needed in surgical treatment of urology dis- eases.Material and methods. Males (n=883, aged 40 to 80 years were included into the study. The main group consisted of patients that underwent laparotomic nephrectomy (LTN group; n=96 and patients who underwent laparoscopic nephrectomy (LSN group; n=53. Dynamics of ambulatory blood pressure monitoring (ABPM data was analyzed in these groups in the immediate postoperative period. The efficacy of a package of non-invasive methods for cardiovascular system assessment was studied. ABPM was performed after nephrectomy (2-nd and 10-th days after surgery in patients with complaints of vertigo episodes or intense general weakness to correct treatment.Results. In LTN group hypotension episodes or blood pressure (BP elevations were observed in 20 (20.8% and 22 (22.9% patients, respectively, on the 2-nd day after the operation. These complications required antihypertensive treatment correction. Patients with hypotension episodes were significantly older than patients with BP elevation and had significantly lower levels of 24-hour systolic BP, night diastolic BP and minimal night systolic BP. Re-adjustment of antihypertensive treatment on the 10-th postoperative day was required to 2 (10% patients with hypotension episodes and to 1 (4.5% patient with BP elevation. Correction of antihypertensive therapy was required to all patients in LSN group on the day 2, and to 32 (60.4% patients on the 10-th day after the operation. Reduction in the incidence of complications (from 1.2% in 2009 to 0.3% in 2011, p<0.001 was observed during the application of cardiovascular non-invasive complex assessment and preoperative preparation in hypertensive patients.Conclusion. The elaborated management algorithm for patients with concomitant hypertension is recommended to reduce the cardiovascular

  16. ALGORITHM FOR MANAGEMENT OF HYPERTENSIVE PATIENTS UNDERWENT UROLOGY INTERVENTIONS

    Directory of Open Access Journals (Sweden)

    S. S. Davydova

    2013-01-01

    Full Text Available Aim. To study the efficacy of cardiovascular non-invasive complex assessment and pre-operative preparation in hypertensive patients needed in surgical treatment of urology dis- eases.Material and methods. Males (n=883, aged 40 to 80 years were included into the study. The main group consisted of patients that underwent laparotomic nephrectomy (LTN group; n=96 and patients who underwent laparoscopic nephrectomy (LSN group; n=53. Dynamics of ambulatory blood pressure monitoring (ABPM data was analyzed in these groups in the immediate postoperative period. The efficacy of a package of non-invasive methods for cardiovascular system assessment was studied. ABPM was performed after nephrectomy (2-nd and 10-th days after surgery in patients with complaints of vertigo episodes or intense general weakness to correct treatment.Results. In LTN group hypotension episodes or blood pressure (BP elevations were observed in 20 (20.8% and 22 (22.9% patients, respectively, on the 2-nd day after the operation. These complications required antihypertensive treatment correction. Patients with hypotension episodes were significantly older than patients with BP elevation and had significantly lower levels of 24-hour systolic BP, night diastolic BP and minimal night systolic BP. Re-adjustment of antihypertensive treatment on the 10-th postoperative day was required to 2 (10% patients with hypotension episodes and to 1 (4.5% patient with BP elevation. Correction of antihypertensive therapy was required to all patients in LSN group on the day 2, and to 32 (60.4% patients on the 10-th day after the operation. Reduction in the incidence of complications (from 1.2% in 2009 to 0.3% in 2011, p<0.001 was observed during the application of cardiovascular non-invasive complex assessment and preoperative preparation in hypertensive patients.Conclusion. The elaborated management algorithm for patients with concomitant hypertension is recommended to reduce the cardiovascular

  17. Summary of Session III

    International Nuclear Information System (INIS)

    Furman, M.A.

    2002-01-01

    This is a summary of the talks presented in Session III ''Simulations of Electron-Cloud Build Up'' of the Mini-Workshop on Electron-Cloud Simulations for Proton and Positron Beams ECLOUD-02, held at CERN, 15-18 April 2002

  18. Session 7: Reserve

    International Nuclear Information System (INIS)

    Bailey, R.; Crockford, G.

    2001-01-01

    The reserve session was devoted to some issues that came up through the workshop, which were grouped into three main areas: The Global Accelerator Network, Problems of stress and how to get organized to minimize them, What should an operations group be responsible for? This paper summarizes the discussions that took place. (author)

  19. Multiparty Asynchronous Session Types

    DEFF Research Database (Denmark)

    Honda, Kohei; Yoshida, Nobuko; Carbone, Marco

    2016-01-01

    Communication is a central elements in software development. As a potential typed foundation for structured communication-centered programming, session types have been studied over the past decade for a wide range of process calculi and programming languages, focusing on binary (two-party) sessio...

  20. Poster Session- Extended Abstracts

    Science.gov (United States)

    Jack D. Alexander III; Jean Findley; Brenda K. Kury; Jan L. Beyers; Douglas S. Cram; Terrell T. Baker; Jon C. Boren; Carl Edminster; Sue A. Ferguson; Steven McKay; David Nagel; Trent Piepho; Miriam Rorig; Casey Anderson; Jeanne Hoadley; Paulette L. Ford; Mark C. Andersen; Ed L. Fredrickson; Joe Truett; Gary W. Roemer; Brenda K. Kury; Jennifer Vollmer; Christine L. May; Danny C. Lee; James P. Menakis; Robert E. Keane; Zhi-Liang Zhu; Carol Miller; Brett Davis; Katharine Gray; Ken Mix; William P. Kuvlesky Jr.; D. Lynn Drawe; Marcia G. Narog; Roger D. Ottmar; Robert E. Vihnanek; Clinton S. Wright; Timothy E. Paysen; Burton K. Pendleton; Rosemary L. Pendleton; Carleton S. White; John Rogan; Doug Stow; Janet Franklin; Jennifer Miller; Lisa Levien; Chris Fischer; Emma Underwood; Robert Klinger; Peggy Moore; Clinton S. Wright

    2008-01-01

    Titles found within Poster Session-Extended Abstracts include:Assessment of emergency fire rehabilitation of four fires from the 2000 fire season on the Vale, Oregon, BLM district: review of the density sampling materials and methods: p. 329 Growth of regreen, seeded for erosion control, in the...

  1. The outreach sessions

    Energy Technology Data Exchange (ETDEWEB)

    Trache, Livius [Horia Hulubei National Institute for Physics and Nuclear Engineering, P.O. Box MG-6, 077125 Bucharest-Magurele (Romania)

    2015-02-24

    These are moderator’s remarks about the outreach day in the middle of the CSSP14, and in particular about the afternoon outreach session in round table format with the announced theme: “CERN at 60 and the internationalization of science”.

  2. Distinct Fos-Expressing Neuronal Ensembles in the Ventromedial Prefrontal Cortex Mediate Food Reward and Extinction Memories.

    Science.gov (United States)

    Warren, Brandon L; Mendoza, Michael P; Cruz, Fabio C; Leao, Rodrigo M; Caprioli, Daniele; Rubio, F Javier; Whitaker, Leslie R; McPherson, Kylie B; Bossert, Jennifer M; Shaham, Yavin; Hope, Bruce T

    2016-06-22

    In operant learning, initial reward-associated memories are thought to be distinct from subsequent extinction-associated memories. Memories formed during operant learning are thought to be stored in "neuronal ensembles." Thus, we hypothesize that different neuronal ensembles encode reward- and extinction-associated memories. Here, we examined prefrontal cortex neuronal ensembles involved in the recall of reward and extinction memories of food self-administration. We first trained rats to lever press for palatable food pellets for 7 d (1 h/d) and then exposed them to 0, 2, or 7 daily extinction sessions in which lever presses were not reinforced. Twenty-four hours after the last training or extinction session, we exposed the rats to either a short 15 min extinction test session or left them in their homecage (a control condition). We found maximal Fos (a neuronal activity marker) immunoreactivity in the ventral medial prefrontal cortex of rats that previously received 2 extinction sessions, suggesting that neuronal ensembles in this area encode extinction memories. We then used the Daun02 inactivation procedure to selectively disrupt ventral medial prefrontal cortex neuronal ensembles that were activated during the 15 min extinction session following 0 (no extinction) or 2 prior extinction sessions to determine the effects of inactivating the putative food reward and extinction ensembles, respectively, on subsequent nonreinforced food seeking 2 d later. Inactivation of the food reward ensembles decreased food seeking, whereas inactivation of the extinction ensembles increased food seeking. Our results indicate that distinct neuronal ensembles encoding operant reward and extinction memories intermingle within the same cortical area. A current popular hypothesis is that neuronal ensembles in different prefrontal cortex areas control reward-associated versus extinction-associated memories: the dorsal medial prefrontal cortex (mPFC) promotes reward seeking, whereas the

  3. Bidirectional effects of inhibiting or activating NMDA receptors on extinction after cocaine self-administration in rats

    Science.gov (United States)

    Hafenbreidel, Madalyn; Todd, Carolynn Rafa; Twining, Robert C.; Tuscher, Jennifer J.; Mueller, Devin

    2014-01-01

    Rationale Extinction of drug seeking is facilitated by NMDA receptor (NMDAr) agonists, but it remains unclear whether extinction is dependent on NMDAr activity. Objectives We investigated the necessity of NMDArs for extinction of cocaine seeking, and whether extinction altered NMDAr expression within extinction-related neuroanatomical loci. Methods Rats were trained to lever press for i.v. infusions of cocaine or sucrose reinforcement prior to extinction training or withdrawal. Results Administration of the NMDAr competitive antagonist CPP prior to four brief extinction sessions impaired subsequent extinction retention. In contrast, post-extinction administration of the NMDAr coagonist D-serine attenuated lever pressing across days as compared to saline administration, indicative of facilitated consolidation of extinction. Furthermore, expression of the NMDAr subunits, GluN2A and GluN2B, was not altered in the ventromedial prefrontal cortex. However, both GluN2A and GluN2B subunit expression in the nucleus accumbens was increased following cocaine self-administration, and this increased expression was relatively resistant to modulation by extinction. Conclusions Our findings demonstrate that extinction of cocaine seeking is bidirectionally mediated by NMDArs and suggest that selective modulation of NMDAr activity could facilitate extinction-based therapies for treatment of cocaine abuse. PMID:24847958

  4. Pavlovian Extinction of the Discriminative Stimulus Effects of Nicotine and Ethanol in Rats Varies as a Function of Context

    Science.gov (United States)

    Troisi, Joseph R., II

    2011-01-01

    Operant extinction contingencies can undermine the discriminative stimulus effects of drugs. Here, nicotine (0.4 mg/kg) and ethanol (0.8 g/kg) first functioned as either an S[superscript D] or S[superscript Delta], in a counterbalanced one-lever go/no-go (across sessions) operant drug discrimination procedure. Pavlovian extinction in the training…

  5. Effects of cycloheximide on extinction in an appetitively motivated operant conditioning task depend on re-exposure duration.

    Science.gov (United States)

    Mierzejewski, Pawel; Olczak, Mieszko; Rogowski, Artur; Kostowski, Wojciech; Samochowiec, Jerzy; Filip, Malgorzata; Przegalinski, Edmund; Bienkowski, Przemyslaw

    2008-08-29

    Little is known about the role of new protein synthesis in extinction of operant responding for natural and chemical reinforcers. In the present study, the authors investigated whether the effects of a protein synthesis inhibitor, cycloheximide (CHX) on extinction of operant responding for sweet reward depended on the duration of re-exposure sessions. In addition, the authors investigated whether the effects of CHX on extinction could generalize to relapse of saccharin seeking induced by discrete cues. CHX injected after short re-exposure sessions (5min) accelerated extinction of non-reinforced responding. In contrast, the drug injected after long re-exposure sessions (30min) partially inhibited extinction. Reinstatement of saccharin seeking induced by the saccharin-paired discrete cues was not altered by the previous treatment with CHX. Concluding, the results of the present study indicate that: (i) the protein synthesis inhibitor, CHX can alter extinction of operant responding for sweet reward in rats; (ii) the effects of CHX on extinction critically depend on the duration of re-exposure/extinction sessions and do not generalize to relapse of saccharin seeking induced by discrete cues.

  6. Frequency of Helicobacter pylori in patients underwent endoscopy

    Directory of Open Access Journals (Sweden)

    Ahmet Tay

    2012-06-01

    Full Text Available Objectives: The aim of this study was to investigate thefrequency of Helicobacter pylori in patients underwent endoscopyeastern Anatolia.Materials and methods: The patients whose endoscopicantral biopsies were taken for any reason in our endoscopyunit in February-June 2010 period were includedand retrospectively investigated. The frequency of Helicobacterpylori was determined as separating the patientsaccording to general, sex and the age groups. Antral biopsieswere stained with hematoxylin-eosin and modified giemsamethod and examined under light microscope andreported as (+ mild, (++ moderate, (+++ severe positiveaccording to their intensities.Results: Biopsy specimens of 1298 patients were includedinto the study. The mean age was 47.5 ± 17.5 years(range 14-88 and 607 of these patients (47% were male.Histopathological evaluation revealed that, 918 of the patientswere (71% positive and 379 (29% were negativefor Helicobacter pylori. Approximately 60% of our patientshad mild, 29% had moderate and 11% had severe positivityfor Helicobacter pylori. No significant difference wasfound in the frequency of Helicobacter pylori betweenwomen and men. The frequencies of Helicobacter pyloriwere 73.2%, 71.5%, 68.6% and 70.4%, respectively, inthe age groups of 14-30 years, 31-45 years, 46-60 yearsand 61-88 years.Conclusion: The frequency of Helicobacter pylori was71% in Eastern Anatolia Region. No statistically significantdifference was found between genders and agegroups in term of the frequency of Helicobacter pylori.

  7. Neural regulation of the time course for cocaine-cue extinction consolidation in rats.

    Science.gov (United States)

    Szalay, Jonathan J; Jordan, Chloe J; Kantak, Kathleen M

    2013-01-01

    Sites within the hippocampus, amygdala and prefrontal cortex may regulate how responses maintained by cues associated with cocaine are extinguished. To test the role of various brain sites in the consolidation of cocaine-cue extinction learning, the dorsal subiculum (dSUB), rostral basolateral amygdala (rBLA) and infralimbic prefrontal cortex (IL) were manipulated in rats. Following cocaine self-administration training (cues present, cocaine available), responding was assessed during 1-h extinction tests (cues present, no cocaine available). To study extinction consolidation specifically, the protein synthesis inhibitor anisomycin or vehicle was infused bilaterally into the dSUB, rBLA or IL either immediately following or 6 h after the first two of three extinction training sessions. With manipulations made immediately after extinction sessions, infusions of anisomycin into the dSUB or the rBLA deterred extinction. Rats maintained elevated levels of cocaine seeking relative to vehicle despite the absence of cocaine delivery. Manipulations of IL had no effect. Control studies showed that bilateral protein synthesis inhibition in dSUB and rBLA 6 h after the extinction sessions ended was unable to deter extinction. Rats reduced cocaine seeking in the usual manner in the absence of cocaine delivery. Collectively, these findings suggest that the dSUB and rBLA are neural substrates important for consolidation of cocaine-cue extinction learning and have time-dependent roles. Understanding the contribution of individual neural substrates for cocaine-cue extinction consolidation may help guide treatment strategies aimed at enhancing cue exposure therapy in cocaine-dependent people. © 2012 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.

  8. The effect of androgen on the retention of extinction memory after conditioned taste aversion in mice.

    Science.gov (United States)

    Suzuki, Ema; Eda-Fujiwara, Hiroko; Satoh, Ryohei; Saito, Rika; Miyamoto, Takenori

    2013-05-01

    Conditioned taste aversion (CTA) induced by the application of a novel taste such as sodium saccharin (Sac) as the conditioned stimulus (CS) and a malaise-inducing agent as the unconditioned stimulus (US), results in acquisition of CTA memory to Sac. In contrast, CTA is extinguished by repeated presentations of the CS without the US, resulting in acquisition of the extinction memory. We examined the effects of androgenic hormones on acquisition and retention of extinction memory in mice. We gonadectomized sexually immature mice and continuously administered androgens to these animals. After sexual maturation, the mice underwent a conditioning period followed by an extinction period. Retrieval tests revealed that the androgen-treated group showed significantly greater retention of extinction memory than the non-treated group 5 weeks later, whereas such significant difference was not observed in acquisition of extinction memory. These results demonstrate the enhancing effect of androgens on retention of extinction memory.

  9. Chronic cannabis use is associated with impaired fear extinction in humans.

    Science.gov (United States)

    Papini, Santiago; Ruglass, Lesia M; Lopez-Castro, Teresa; Powers, Mark B; Smits, Jasper A J; Hien, Denise A

    2017-01-01

    The use of fear conditioning and extinction paradigms to examine intermediate phenotypes of anxiety and stress-related disorders has facilitated the identification of neurobiological mechanisms that underlie specific components of abnormal psychological functioning. Across species, acute pharmacologic manipulation of the endogenous cannabinoid system has provided evidence of its critical role in fear extinction, but the effects of chronic cannabis on extinction are relatively understudied. In rats, chronic cannabinoid administration impairs fear extinction in a drug-free state. Here we examine whether chronic cannabis use is associated with impaired fear extinction in humans. Participants were healthy chronic cannabis users (n = 20) and nonuser controls with minimal lifetime cannabis use (n = 20) matched on age, sex, and race who all screened negative for psychiatric disorders. A 2-day differential fear conditioning paradigm was used to test the hypothesis that chronic cannabis use would be associated with impaired extinction of the skin conductance response. Consistent with hypotheses, chronic cannabis use was associated with reduced within-session extinction of skin conductance response on Day 1 (d = 0.78), and between-session extinction on Day 2 (d = 0.76). Unexpectedly, cannabis use was also associated with reduced subjective differentiation between threat and safety stimuli during conditioning. Replication and translation of findings are necessary to test potential mechanisms directly and examine whether impairments can be reversed pharmacologically or after a period of cannabis abstinence. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  10. Extinction learning deficit in a rodent model of attention-deficit hyperactivity disorder

    Directory of Open Access Journals (Sweden)

    Brackney Ryan J

    2012-12-01

    Full Text Available Abstract Background Deficient operant extinction has been hypothesized to be constitutive of ADHD dysfunction. In order to elucidate the behavioral mechanisms underlying this deficit, the performance of an animal model of ADHD, the spontaneously hypertensive rat (SHR, was compared against the performance of a control strain, the Wistar-Kyoto rat (WKY during extinction. Method Following extensive training of lever pressing under variable interval schedules of food reinforcement (reported previously, SHR and WKY rats were exposed to two sessions of extinction training. Extinction data was analyzed using the Dynamic Bi-Exponential Refractory Model (DBERM of operant performance. DBERM assumes that operant responses are organized in bouts separated by pauses; during extinction, bouts may decline across multiple dimensions, including frequency and length. DBERM parameters were estimated using hierarchical Bayesian modeling. Results SHR responded more than WKY during the first extinction session. DBERM parameter estimates revealed that, at the onset of extinction, SHR produced more response bouts than WKY. Over the course of extinction, response bouts progressively shortened for WKY but not for SHR. Conclusions Based on prior findings on the sensitivity of DBERM parameters to motivational and schedule manipulations, present data suggests that (1 more frequent response bouts in SHR are likely related to greater incentive motivation, and (2 the persistent length of bouts in SHR are likely related to a slower updating of the response-outcome association. Overall, these findings suggest specific motivational and learning deficits that may explain ADHD-related impairments in operant performance.

  11. Modelling interstellar extinction: Pt. 1

    International Nuclear Information System (INIS)

    Jones, A.P.

    1988-01-01

    Several methods of calculating the extinction of porous silicate grains are discussed, these include effective medium theories and hollow spherical shells. Porous silicate grains are shown to produce enhanced infrared, ultraviolet and far-ultraviolet extinction and this effect can be used to reduce the abundance of carbon required to match the average interstellar extinction, however, matching the visual extinction is rather more problematical. We have shown that the enhanced extinction at long and short wavelengths have different origins, and have explained why the visual extinction is little affected by porosity. The implications of porous grains in the interstellar medium are discussed with particular reference to surface chemistry, the polarization of starlight, and their dynamical evolution. (author)

  12. Extinction Events Can Accelerate Evolution

    DEFF Research Database (Denmark)

    Lehman, Joel; Miikkulainen, Risto

    2015-01-01

    Extinction events impact the trajectory of biological evolution significantly. They are often viewed as upheavals to the evolutionary process. In contrast, this paper supports the hypothesis that although they are unpredictably destructive, extinction events may in the long term accelerate...... evolution by increasing evolvability. In particular, if extinction events extinguish indiscriminately many ways of life, indirectly they may select for the ability to expand rapidly through vacated niches. Lineages with such an ability are more likely to persist through multiple extinctions. Lending...... computational support for this hypothesis, this paper shows how increased evolvability will result from simulated extinction events in two computational models of evolved behavior. The conclusion is that although they are destructive in the short term, extinction events may make evolution more prolific...

  13. Acoustic integrated extinction

    OpenAIRE

    Norris, Andrew N.

    2015-01-01

    The integrated extinction (IE) is defined as the integral of the scattering cross section as a function of wavelength. Sohl et al. (2007 J. Acoust. Soc. Am. 122, 3206–3210. (doi:10.1121/1.2801546)) derived an IE expression for acoustic scattering that is causal, i.e. the scattered wavefront in the forward direction arrives later than the incident plane wave in the background medium. The IE formula was based on electromagnetic results, for which scattering is causal by default. Here, we der...

  14. Mass extinctions of Earth

    International Nuclear Information System (INIS)

    Fernandez, B.; Fernandez, P.; Pereira, B.

    2015-01-01

    Throughout the history of our planet, there have been global phenomena which have led to the disappearance of a large number of species: It is what is known as mass or massive extinctions. This article will make a tour of these large events, from the most remote antiquity to the present day. Today we find ourselves immersed in a process unprecedented since we are eyewitnesses and, more important still, an active part in the decision-making process to try to mitigate their effects. (Author)

  15. Tyrosine receptor kinase B receptor activation reverses the impairing effects of acute nicotine on contextual fear extinction.

    Science.gov (United States)

    Kutlu, Munir Gunes; Cole, Robert D; Connor, David A; Natwora, Brendan; Gould, Thomas J

    2018-03-01

    Anxiety and stress disorders have been linked to deficits in fear extinction. Our laboratory and others have demonstrated that acute nicotine impairs contextual fear extinction, suggesting that nicotine exposure may have negative effects on anxiety and stress disorder symptomatology. However, the neurobiological mechanisms underlying the acute nicotine-induced impairment of contextual fear extinction are unknown. Therefore, based on the previous studies showing that brain-derived neurotrophic factor is central for fear extinction learning and acute nicotine dysregulates brain-derived neurotrophic factor signaling, we hypothesized that the nicotine-induced impairment of contextual fear extinction may involve changes in tyrosine receptor kinase B signaling. To test this hypothesis, we systemically, intraperitoneally, injected C57BL/6J mice sub-threshold doses (2.5 and 4.0 mg/kg) of 7,8-dihydroxyflavone, a small-molecule tyrosine receptor kinase B agonist that fully mimics the effects of brain-derived neurotrophic factor, or vehicle an hour before each contextual fear extinction session. Mice also received injections, intraperitoneally, of acute nicotine (0.18 mg/kg) or saline 2-4 min before extinction sessions. While the animals that received only 7,8-dihydroxyflavone did not show any changes in contextual fear extinction, 4.0 mg/kg of 7,8-dihydroxyflavone ameliorated the extinction deficits in mice administered acute nicotine. Overall, these results suggest that acute nicotine-induced impairment of context extinction may be related to a disrupted brain-derived neurotrophic factor signaling.

  16. Deficient fear extinction memory in posttraumatic stress disorder.

    Science.gov (United States)

    Wicking, Manon; Steiger, Frauke; Nees, Frauke; Diener, Slawomira J; Grimm, Oliver; Ruttorf, Michaela; Schad, Lothar R; Winkelmann, Tobias; Wirtz, Gustav; Flor, Herta

    2016-12-01

    Posttraumatic stress disorder (PTSD) might be maintained by deficient extinction memory. We used a cued fear conditioning design with extinction and a post-extinction phase to provoke the return of fear and examined the role of the interplay of amygdala, hippocampus and prefrontal regions. We compared 18 PTSD patients with two healthy control groups: 18 trauma-exposed subjects without PTSD (nonPTSD) and 18 healthy controls (HC) without trauma experience. They underwent a three-day ABC-conditioning procedure in a functional magnetic resonance imaging scanner. Two geometric shapes that served as conditioned stimuli (CS) were presented in the context of virtual reality scenes. Electric painful stimuli were delivered after one of the two shapes (CS+) during acquisition (in context A), while the other (CS-) was never paired with pain. Extinction was performed in context B and extinction memory was tested in a novel context C. The PTSD patients showed significantly higher differential skin conductance responses than the non-PTSD and HC and higher differential amygdala and hippocampus activity than the HC in context C. In addition, elevated arousal to the CS+ during extinction and to the CS- throughout the experiment was present in the PTSD patients but self-reported differential valence or contingency were not different. During extinction recall, differential amygdala activity correlated positively with the intensity of numbing and ventromedial prefrontal cortex activity correlated positively with behavioral avoidance. PTSD patients show heightened return of fear in neural and peripheral measures. In addition, self-reported arousal was high to both danger (CS+) and safety (CS-) cues. These results suggest that a deficient maintenance of extinction and a failure to identify safety signals might contribute to PTSD symptoms, whereas non-PTSD subjects seem to show normal responses. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Extinction of H II regions

    International Nuclear Information System (INIS)

    Israel, F.P.; Kennicutt, R.C.

    1980-01-01

    Visual extinction of H II regions in nine nearby galaxies as derived from the ratio of the radio continuum emission to H-alpha emission is systematically larger than visual extinction deduced from the Balmer lines alone, if one assumes a value Av/E(B-V) 3. An optically-limited sample of about 30 extragalactic H II regions has a mean extinction of 1.7 m in the visual while about 1.2 m is not seen in the reddening of the Balmer lines. Both reddening and extinction decreases with increasing galactic radius, at least for M33 and M101

  18. A reconciliation of extinction theories

    International Nuclear Information System (INIS)

    Sabine, T.M.

    1988-01-01

    The differences between previous theoretical treatments of extinction based on the Darwin intensity equations arise because of the different functional form chosen for the coupling constant σ. When the same function is used these theories make closely similar predictions. It is shown that a limiting condition on integrated intensity as the crystal size increases puts restrictions on the functions which may be used. A Lorentzian or Fresnellian function can be used for primary extinction while secondary extinction requires a Gaussian, rectangular or triangular function. An analytical expression is given for the variation in the value of the extinction factor with scattering angle. (orig.)

  19. ICALEPS 2005 : opening session

    CERN Multimedia

    Maximilien Brice

    2005-01-01

    ICALEPCS 2005, the tenth International Conference on Accelerator and Large Experimental Physics Control Systems, will be held in Geneva, Switzerland, 10-14 Oct. 2005 at the International Conference Center Geneva (CICG). ICALEPCS 2005 thus falls in the year that UNESCO has declared the "World Year of Physics". ICALEPCS covers all aspects of control and operation of Experimental Physics facilities such as particle accelerators, particle detectors, optical telescopes, radio telescopes, nuclear fusion facilities like Tokamaks, nuclear reactors, lasers, etc .... Opening session by . A. Daneels (CERN): Introducting ICALEPCS 2005 . C.Lamprecht (Republic & State of Geneva): Welcome speech . J. Lister (EPFL): Welcome speech . J. Engelen (CERN): The machine and experiment challenges of LHC

  20. Session: Hard Rock Penetration

    Energy Technology Data Exchange (ETDEWEB)

    Tennyson, George P. Jr.; Dunn, James C.; Drumheller, Douglas S.; Glowka, David A.; Lysne, Peter

    1992-01-01

    This session at the Geothermal Energy Program Review X: Geothermal Energy and the Utility Market consisted of five presentations: ''Hard Rock Penetration - Summary'' by George P. Tennyson, Jr.; ''Overview - Hard Rock Penetration'' by James C. Dunn; ''An Overview of Acoustic Telemetry'' by Douglas S. Drumheller; ''Lost Circulation Technology Development Status'' by David A. Glowka; ''Downhole Memory-Logging Tools'' by Peter Lysne.

  1. Session: Reservoir Technology

    Energy Technology Data Exchange (ETDEWEB)

    Renner, Joel L.; Bodvarsson, Gudmundur S.; Wannamaker, Philip E.; Horne, Roland N.; Shook, G. Michael

    1992-01-01

    This session at the Geothermal Energy Program Review X: Geothermal Energy and the Utility Market consisted of five papers: ''Reservoir Technology'' by Joel L. Renner; ''LBL Research on the Geysers: Conceptual Models, Simulation and Monitoring Studies'' by Gudmundur S. Bodvarsson; ''Geothermal Geophysical Research in Electrical Methods at UURI'' by Philip E. Wannamaker; ''Optimizing Reinjection Strategy at Palinpinon, Philippines Based on Chloride Data'' by Roland N. Horne; ''TETRAD Reservoir Simulation'' by G. Michael Shook

  2. 98th LHCC meeting Agenda OPEN Session and CLOSED Session

    CERN Document Server

    CERN. Geneva

    2009-01-01

    OPEN Session on Wednesday, 8 July at 9h00-11h00 in Main Auditorium, Live webcast, followed by CLOSED Session, Conference room 160-1-009 11h20-17h00. CLOSED Session continued on Thursday, 9 July at 9h00-12h30

  3. Bidirectional effects of cannabidiol on contextual fear memory extinction

    Directory of Open Access Journals (Sweden)

    Chenchen Song

    2016-12-01

    Full Text Available Cannabidiol (CBD has been established to have both acute and long-lasting effects to reduce fear memory expression. The long-lasting impact might be mediated by an enhancement of memory extinction or an impairment of memory reconsolidation. Here, we directly compared the effects of i.p. injections of cannabidiol (10 mg/kg with those of the NMDA receptor antagonist MK-801 (0.1 mg/kg and partial agonist D-cycloserine (DCS; 15 mg/kg in order to determine the mnemonic basis of long-term fear reduction. We showed that under conditions of strong fear conditioning, CBD reduced contextual fear memory expression both acutely during the extinction session as well as later at a fear retention test. The latter test reduction was replicated by DCS, but MK-801 instead elevated test freezing. In contrast, when initial conditioning was weaker, CBD and MK-801 had similar effects to increase freezing at the fear retention test relative to vehicle controls, whereas DCS had no observable impact. This pattern of results is consistent with CBD enhancing contextual fear memory extinction when the initial conditioning is strong, but impairing extinction when conditioning is weak. This bidirectional effect of CBD may be related to stress levels induced by conditioning and evoked at retrieval during extinction, rather than the strength of the memory per se.

  4. Involvement of CRFR1 in the Basolateral Amygdala in the Immediate Fear Extinction Deficit.

    Science.gov (United States)

    Hollis, Fiona; Sevelinges, Yannick; Grosse, Jocelyn; Zanoletti, Olivia; Sandi, Carmen

    2016-01-01

    Several animal and clinical studies have highlighted the ineffectiveness of fear extinction sessions delivered shortly after trauma exposure. This phenomenon, termed the immediate extinction deficit, refers to situations in which extinction programs applied shortly after fear conditioning may result in the reduction of fear behaviors (in rodents, frequently measured as freezing responses to the conditioned cue) during extinction training, but failure to consolidate this reduction in the long term. The molecular mechanisms driving this immediate extinction resistance remain unclear. Here we present evidence for the involvement of the corticotropin releasing factor (CRF) system in the basolateral amygdala (BLA) in male Wistar rats. Intra-BLA microinfusion of the CRFR 1 antagonist NBI30775 enhances extinction recall, whereas administration of the CRF agonist CRF 6-33 before delayed extinction disrupts recall of extinction. We link the immediate fear extinction deficit with dephosphorylation of GluA1 glutamate receptors at Ser 845 and enhanced activity of the protein phosphatase calcineurin in the BLA. Their reversal after treatment with the CRFR 1 antagonist indicates their dependence on CRFR 1 actions. These findings can have important implications for the improvement of therapeutic approaches to trauma, as well as furthering our understanding of the neurobiological mechanisms underlying fear-related disorders.

  5. Combined Neuropeptide S and D-Cycloserine Augmentation Prevents the Return of Fear in Extinction-Impaired Rodents: Advantage of Dual versus Single Drug Approaches

    Science.gov (United States)

    Maurer, Verena; Murphy, Conor; Schmuckermair, Claudia; Muigg, Patrick; Neumann, Inga D.; Whittle, Nigel

    2016-01-01

    Background: Despite its success in treating specific anxiety disorders, the effect of exposure therapy is limited by problems with tolerability, treatment resistance, and fear relapse after initial response. The identification of novel drug targets facilitating fear extinction in clinically relevant animal models may guide improved treatment strategies for these disorders in terms of efficacy, acceleration of fear extinction, and return of fear. Methods: The extinction-facilitating potential of neuropeptide S, D-cycloserine, and a benzodiazepine was investigated in extinction-impaired high anxiety HAB rats and 129S1/SvImJ mice using a classical cued fear conditioning paradigm followed by extinction training and several extinction test sessions to study fear relapse. Results: Administration of D-cycloserine improved fear extinction in extinction-limited, but not in extinction-deficient, rodents compared with controls. Preextinction neuropeptide S caused attenuated fear responses in extinction-deficient 129S1/SvImJ mice at extinction training onset and further reduced freezing during this session. While the positive effects of either D-cycloserine or neuropeptide S were not persistent in 129S1/SvImJ mice after 10 days, the combination of preextinction neuropeptide S with postextinction D-cycloserine rendered the extinction memory persistent and context independent up to 5 weeks after extinction training. This dual pharmacological adjunct to extinction learning also protected against fear reinstatement in 129S1/SvImJ mice. Conclusions: By using the potentially nonsedative anxiolytic neuropeptide S and the cognitive enhancer D-cycloserine to facilitate deficient fear extinction, we provide here the first evidence of a purported efficacy of a dual over a single drug approach. This approach may render exposure sessions less aversive and more efficacious for patients, leading to enhanced protection from fear relapse in the long term. PMID:26625894

  6. Extinction of Harrington's mountain goat

    International Nuclear Information System (INIS)

    Mead, J.I.; Martin, P.S.; Euler, R.C.; Long, A.; Jull, A.J.T.; Toolin, L.J.; Donahue, D.J.; Linick, T.W.

    1986-01-01

    Keratinous horn sheaths of the extinct Harrington's mountain goat, Oreamnos harringtoni, were recovered at or near the surface of dry caves of the Grand Canyon, Arizona. Twenty-three separate specimens from two caves were dated nondestructively by the tandem accelerator mass spectrometer (TAMS). Both the TAMS and the conventional dates indicate that Harrington's mountain goat occupied the Grand Canyon for at least 19,000 years prior to becoming extinct by 11,160 +/- 125 radiocarbon years before present. The youngest average radiocarbon dates on Shasta ground sloths, Nothrotheriops shastensis, from the region are not significantly younger than those on extinct mountain goats. Rather than sequential extinction with Harrington's mountain goat disappearing from the Grand Canyon before the ground sloths, as one might predict in view of evidence of climatic warming at the time, the losses were concurrent. Both extinctions coincide with the regional arrival of Clovis hunters

  7. Role of Corticotropin Releasing Factor 1 Signaling in Cocaine Seeking during Early Extinction in Female and Male Rats.

    Science.gov (United States)

    Cason, Angie M; Kohtz, Amy; Aston-Jones, Gary

    2016-01-01

    Locus coeruleus norepinephrine (LC-NE) and corticotropin releasing factor (CRF) neurons are involved in stress responses, including stress's ability to drive drug relapse. Previous animal studies indicate that female rats exhibit greater drug seeking than male rats during initial drug abstinence. Moreover, females are more sensitive to the effect of stress to drive drug seeking than males. Finally, LC-NE neurons are more sensitive to CRF in females compared to males. We hypothesized that increased drug seeking in females on extinction day one (ED1) is due to increased response to the stress of early withdrawal and is dependent upon the increased response of LC in females to CRF. We predicted that LC-NE neurons would exhibit Fos activation on ED1, and that blocking CRF1 signaling would decrease drug seeking on ED1 measured by responding on an active lever previously associated with cocaine self- administration. After chronic cocaine self-administration, female and male rats underwent a test for initial extinction responding by measuring lever pressing in the absence of cocaine. Prior to this Extinction Day 1 (ED1) session, rats were injected with vehicle or the selective CRF1 antagonist (CP) to measure effects of CRF antagonism on drug seeking during early abstinence. ED1 increased corticosterone in female rats, in proportion to lever responding in male and female, indicating that ED1 was stressful. Pretreatment with CP decreased cocaine seeking on ED1 more effectively in female compared to male rats. This increase in responding was associated with an increase in activation of LC NE neurons. Together, these findings indicate that stress, and signaling at CRF receptors in LC, may be involved in the increased drug seeking during initial abstinence.

  8. Role of Corticotropin Releasing Factor 1 Signaling in Cocaine Seeking during Early Extinction in Female and Male Rats.

    Directory of Open Access Journals (Sweden)

    Angie M Cason

    Full Text Available Locus coeruleus norepinephrine (LC-NE and corticotropin releasing factor (CRF neurons are involved in stress responses, including stress's ability to drive drug relapse. Previous animal studies indicate that female rats exhibit greater drug seeking than male rats during initial drug abstinence. Moreover, females are more sensitive to the effect of stress to drive drug seeking than males. Finally, LC-NE neurons are more sensitive to CRF in females compared to males. We hypothesized that increased drug seeking in females on extinction day one (ED1 is due to increased response to the stress of early withdrawal and is dependent upon the increased response of LC in females to CRF. We predicted that LC-NE neurons would exhibit Fos activation on ED1, and that blocking CRF1 signaling would decrease drug seeking on ED1 measured by responding on an active lever previously associated with cocaine self- administration. After chronic cocaine self-administration, female and male rats underwent a test for initial extinction responding by measuring lever pressing in the absence of cocaine. Prior to this Extinction Day 1 (ED1 session, rats were injected with vehicle or the selective CRF1 antagonist (CP to measure effects of CRF antagonism on drug seeking during early abstinence. ED1 increased corticosterone in female rats, in proportion to lever responding in male and female, indicating that ED1 was stressful. Pretreatment with CP decreased cocaine seeking on ED1 more effectively in female compared to male rats. This increase in responding was associated with an increase in activation of LC NE neurons. Together, these findings indicate that stress, and signaling at CRF receptors in LC, may be involved in the increased drug seeking during initial abstinence.

  9. Measuring Extinction with ALE

    Science.gov (United States)

    Zimmer, Peter C.; McGraw, J. T.; Gimmestad, G. G.; Roberts, D.; Stewart, J.; Smith, J.; Fitch, J.

    2007-12-01

    ALE (Astronomical LIDAR for Extinction) is deployed at the University of New Mexico's (UNM) Campus Observatory in Albuquerque, NM. It has begun a year-long testing phase prior deployment at McDonald Observatory in support of the CCD/Transit Instrument II (CTI-II). ALE is designed to produce a high-precision measurement of atmospheric absorption and scattering above the observatory site every ten minutes of every moderately clear night. LIDAR (LIght Detection And Ranging) is the VIS/UV/IR analog of radar, using a laser, telescope and time-gated photodetector instead of a radio transmitter, dish and receiver. In the case of ALE -- an elastic backscatter LIDAR -- 20ns-long, eye-safe laser pulses are launched 2500 times per second from a 0.32m transmitting telescope co-mounted with a 50mm short-range receiver on an alt-az mounted 0.67m long-range receiver. Photons from the laser pulse are scattered and absorbed as the pulse propagates through the atmosphere, a portion of which are scattered into the field of view of the short- and long-range receiver telescopes and detected by a photomultiplier. The properties of a given volume of atmosphere along the LIDAR path are inferred from both the altitude-resolved backscatter signal as well as the attenuation of backscatter signal from altitudes above it. We present ALE profiles from the commissioning phase and demonstrate some of the astronomically interesting atmospheric information that can be gleaned from these data, including, but not limited to, total line-of-sight extinction. This project is funded by NSF Grant 0421087.

  10. Music therapy inhibits morphine-seeking behavior via GABA receptor and attenuates anxiety-like behavior induced by extinction from chronic morphine use.

    Science.gov (United States)

    Kim, Ki Jin; Lee, Sang Nam; Lee, Bong Hyo

    2018-05-01

    Morphine is a representative pain killer. However, repeated use tends to induce addiction. Music therapy has been gaining interest as a useful type of therapy for neuropsychiatric diseases. The present study examined whether Korean traditional music (KT) could suppress morphine-seeking behavior and anxiety-like behavior induced by extinction from chronic morphine use and additionally investigated a possible neuronal mechanism. Male Sprague-Dawley rats were trained to intravenously self-administer morphine hydrochloride (1.0 mg/kg) using a fixed ratio 1 schedule in daily 2 h session during 3 weeks. After training, rats who established baseline (variation less than 20% of the mean of infusion for 3 consecutive days) underwent extinction. Music was played twice a day during extinction. In the second experiment, the selective antagonists of GABA A and GABA B receptors were treated before the last playing to investigate the neuronal mechanism focusing on the GABA receptor pathway. Another experiment of elevated plus maze was performed to investigate whether music therapy has an anxiolytic effect at the extinction phase. KT but not other music (Indian road or rock music) reduced morphine-seeking behavior induced by a priming challenge with morphine. And, this effect was blocked by the GABA receptor antagonists. In addition, KT showed anxiolytic effects against withdrawal from morphine. Results of this study suggest that KT suppresses morphine-seeking behavior via GABA receptor pathway. In addition, KT showed to have anxiolytic effects, suggesting it has bi-directional effects on morphine. Copyright © 2018 Elsevier B.V. All rights reserved.

  11. Attentional Control and Fear Extinction in Subclinical Fear: An Exploratory Study

    Directory of Open Access Journals (Sweden)

    Eduard Forcadell

    2017-09-01

    Full Text Available Attentional control (AC and fear extinction learning are known to be involved in pathological anxiety. In this study we explored whether individual differences in non-emotional AC were associated with individual differences in the magnitude and gradient of fear extinction (learning and recall. In 50 individuals with fear of spiders, we collected measures of non-emotional AC by means of self-report and by assessing the functioning of the major attention networks (executive control, orienting, and alerting. The participants then underwent a paradigm assessing fear extinction learning and extinction recall. The two components of the orienting network functioning (costs and benefits were significantly associated with fear extinction gradient over and above the effects of trait anxiety. Specifically, participants with enhanced orienting costs (i.e., difficulties in disengaging attention from cues not relevant for the task showed faster extinction learning, while those with enhanced orienting benefits (i.e., attention facilitated by valid cues exhibited faster extinction recall as measured by fear-potentiated startle and Unconditioned Stimulus expectancies, respectively. Our findings suggest that, in non-emotional conditions, the orienting component of attention may be predictive of fear extinction. They also show that the use of fear extinction gradients and the exploration of individual differences in non-emotional AC (using performance-based measures of attentional network functioning can provide a better understanding of individual differences in fear learning. Our findings also may help to understand differences in exposure therapy outcomes.

  12. Individual variation in working memory is associated with fear extinction performance.

    Science.gov (United States)

    Stout, Daniel M; Acheson, Dean T; Moore, Tyler M; Gur, Ruben C; Baker, Dewleen G; Geyer, Mark A; Risbrough, Victoria B

    2018-03-01

    PTSD has been associated consistently with abnormalities in fear acquisition and extinction learning and retention. Fear acquisition refers to learning to discriminate between threat and safety cues. Extinction learning reflects the formation of a new inhibitory-memory that competes with a previously learned threat-related memory. Adjudicating the competition between threat memory and the new inhibitory memory during extinction may rely, in part, on cognitive processes such as working memory (WM). Despite significant shared neural circuits and signaling pathways the relationship between WM, fear acquisition, and extinction is poorly understood. Here, we analyzed data from a large sample of healthy Marines who underwent an assessment battery including tests of fear acquisition, extinction learning, and WM (N-back). Fear potentiated startle (FPS), fear expectancy ratings, and self-reported anxiety served as the primary dependent variables. High WM ability (N = 192) was associated with greater CS + fear inhibition during the late block of extinction and greater US expectancy change during extinction learning compared to individuals with low WM ability (N = 204). WM ability was not associated with magnitude of fear conditioning/expression. Attention ability was unrelated to fear acquisition or extinction supporting specificity of WM associations with extinction. These results support the conclusion that individual differences in WM may contribute to regulating fear responses. Copyright © 2018. Published by Elsevier Ltd.

  13. High-affinity α4β2 nicotinic receptors mediate the impairing effects of acute nicotine on contextual fear extinction.

    Science.gov (United States)

    Kutlu, Munir Gunes; Holliday, Erica; Gould, Thomas J

    2016-02-01

    Previously, studies from our lab have shown that while acute nicotine administered prior to training and testing enhances contextual fear conditioning, acute nicotine injections prior to extinction sessions impair extinction of contextual fear. Although there is also strong evidence showing that the acute nicotine's enhancing effects on contextual fear conditioning require high-affinity α4β2 nicotinic acetylcholine receptors (nAChRs), it is unknown which nAChR subtypes are involved in the acute nicotine-induced impairment of contextual fear extinction. In this study, we investigated the effects of acute nicotine administration on contextual fear extinction in knock-out (KO) mice lacking α4, β2 or α7 subtypes of nAChRs and their wild-type (WT) littermates. Both KO and WT mice were first trained and tested for contextual fear conditioning and received a daily contextual extinction session for 4 days. Subjects received intraperitoneal injections of nicotine (0.18 mg/kg) or saline 2-4 min prior to each extinction session. Our results showed that the mice that lack α4 and β2 subtypes of nAChRs showed normal contextual fear extinction but not the acute nicotine-induced impairment while the mice that lack the α7 subtype showed both normal contextual extinction and nicotine-induced impairment of contextual extinction. In addition, control experiments showed that acute nicotine-induced impairment of contextual fear extinction persisted when nicotine administration was ceased and repeated acute nicotine administrations alone did not induce freezing behavior in the absence of context-shock learning. These results clearly demonstrate that high-affinity α4β2 nAChRs are necessary for the effects of acute nicotine on contextual fear extinction. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Inhibiting glycine transporter-1 facilitates cocaine-cue extinction and attenuates reacquisition of cocaine-seeking behavior.

    Science.gov (United States)

    Nic Dhonnchadha, Bríd Á; Pinard, Emmanuel; Alberati, Daniela; Wettstein, Joseph G; Spealman, Roger D; Kantak, Kathleen M

    2012-04-01

    Combining extinction training with cognitive-enhancing pharmacotherapy represents a novel strategy for improving the efficacy of exposure therapy for drug relapse prevention. We investigated if the selective glycine transporter-1 (GlyT-1) inhibitor RO4543338 could facilitate extinction of cocaine-conditioned responses and attenuate reacquisition of cocaine-seeking behavior. Rats were trained to self-administer cocaine (0.3mg/kg), which was associated with a 2-s light cue under a second-order schedule of i.v. drug injection. Rats received vehicle, 30 or 45mg/kg of RO4543338 prior to three 1-h extinction-training sessions spaced at weekly intervals. Responses were extinguished by substituting saline for cocaine while maintaining response-contingent cue presentations. Reacquisition of cocaine-seeking behavior during self-administration sessions began 1 week after the last extinction session. Control experiments were conducted under conditions that precluded explicit extinction of cocaine-conditioned responses. Compared to vehicle, 30 and 45mg/kg RO4543338 significantly decreased responding early in extinction training and during subsequent reacquisition sessions. The latter effect persisted for at least five sessions. In control studies, reacquisition of cocaine-seeking behavior was not altered when RO4543338 was administered either prior to weekly self-administration control sessions or prior to weekly control sessions in which cocaine and cues were omitted and the levers retracted. As the GlyT-1 inhibitor facilitated cocaine-cue extinction learning and attenuated subsequent reacquisition of cocaine-seeking behavior, this class of compounds may have utility as a pharmacological adjunct to cocaine-cue exposure therapy in addicts. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  15. The Extinction of the Conulariids

    Directory of Open Access Journals (Sweden)

    Spencer G. Lucas

    2012-03-01

    Full Text Available Conulariids are unusual extinct metazoans most often considered to be a group of scyphozoan cnidarians or close relatives. Generally, the temporal range of conulariid fossils is perceived to be late Precambrian or Cambrian to Triassic, though a supposed Cretaceous conulariid from Peru was published 46 years ago. A re-evaluation of this fossil indicates it is not a conulariid, but instead a pinnacean bivalve (Pinna sp., confirming that the geologically youngest conulariids are of Late Triassic age. However, a review of the Triassic conulariid fossil record indicates it is very sparse, with only eight published records. It does not provide a reliable basis for analyzing the structure of conulariid extinction. Nevertheless, conulariid extinction still appears to have taken place very close to the end of the Triassic. The cause of conulariid extinction may have been the onset of the Mesozoic marine revolution, in which durivorous predators developed new mechanisms for preying on the epifaunal benthos, including the conulariids.

  16. Teaching statistics to medical undergraduates using interactive and participatory sessions

    Directory of Open Access Journals (Sweden)

    THULASINGAM MAHALAKSHMY

    2013-10-01

    Full Text Available Introduction: In India, medical undergraduates think that statistics is difficult to understand. Often, it is taught just before final assessment examination using didactic lectures, with little use of medical examples and less focus on application. Hence, we prepared interactive, participatory sessions for teaching biostatistics to medical undergraduate. Methods: The sessions were delivered by a facilitator. It had clearly specified objectives and teaching learning strategies. A needs assessment was done by interviewing the students who had undergone traditional biostatistics teaching methodology. Specific learning objectives for the sessions were finalized using the Delphi technique and review of University syllabus. Two trained Community Medicine faculties designed the lesson plans ‘backwards’ from desired outcome to content, teaching/learning strategies, assessment and evaluation process (Outcomes-based lesson planning. Forty, third-semester (Para-clinical phase of the second year medical undergraduates undertook these seven teaching sessions. The session followed adult learning principles and included group discussions, games and reflections. We evaluated the impact of the sessions using in-depth interviews, retrospective post-then-preself- assessment and a pre-announced written test. Results: With traditional statistics teaching methodology, students perceived it as a standalone subject and were not interested in statistics. Students who underwent the sessions commented that the sessions were enjoyable, interesting, and participatory and more than %90 of them felt they were engaged throughout the session. They also narrated various instances where they could apply the biostatistics learning. In the post-then-pre-assessment median post-session scores for all the objectives were significantly higher (p <0.050. Conclusion: Use of interactive, participatory sessions for teaching biostatistics to medical undergraduates resulted in a

  17. Reconsidering the extinction of ichthyosaurs

    OpenAIRE

    Fischer, Valentin

    2010-01-01

    Despite their extreme adaptation to life in open sea, ichthyosaurs were one of the first major groups of post-Triassic marine reptiles to disappear, at the end of Cenomanian, whereas plesiosaurs, mosasaurs and numerous families of marine crocodiles and sea turtles disappeared during the Cretaceous/Paleocene Extinction Event. It has been proposed that unique biological factors drove ichthyosaurs to extinction, namely a break in the food chain at the level of belemnites or a progressive ecologi...

  18. The Sixth Great Mass Extinction

    Science.gov (United States)

    Wagler, Ron

    2012-01-01

    Five past great mass extinctions have occurred during Earth's history. Humanity is currently in the midst of a sixth, human-induced great mass extinction of plant and animal life (e.g., Alroy 2008; Jackson 2008; Lewis 2006; McDaniel and Borton 2002; Rockstrom et al. 2009; Rohr et al. 2008; Steffen, Crutzen, and McNeill 2007; Thomas et al. 2004;…

  19. Docosahexaenoic Acid Helps to Lessen Extinction Memory in Rats

    Directory of Open Access Journals (Sweden)

    Michio Hashimoto

    2018-02-01

    Full Text Available Abstract: Memory extinction is referred to as a learning process in which a conditioned response (CR progressively reduces over time as an animal learns to uncouple a response from a stimulus. Extinction occurs when the rat is placed into a context without shock after training. Docosahexaenoic acid (DHA, C22:6, n-3 is implicated in memory formation in mammalian brains. In a two-way active shuttle-avoidance apparatus, we examined whether DHA affects the extinction memory and the expression of brain cognition-related proteins, including gastrin-releasing peptide receptor (GRPR, brain-derived neurotrophic factor receptor (BDNFR tyrosine kinase receptor B (TrKB, and N-methyl-d-aspartate receptor (NMDAR subunits NR2A and NR2B. Also, the protein levels of GRP, BDNF, postsynaptic density protein-95 (PSD-95, and vesicular acetylcholine transporter (VAChT, and the antioxidative potentials, in terms of lipid peroxide (LPO and reactive oxygen species (ROS, were examined in the hippocampus. During the acquisition phase, the rats received a conditioned stimulus (CS-tone paired with an unconditioned stimulus (UCS foot shock for three consecutive days (Sessions S1, S2, and S3, each consisting of 30-trials after 12 weeks of oral administration of DHA. After a three-day interval, the rats were re-subjected to two extinction sessions (S4, S5, each comprising 30 trials of CS alone. During the acquisition training in S1, the shock-related avoidance frequency (acquisition memory was significantly higher in the DHA-administered rats compared with the control rats. The avoidance frequency, however, decreased with successive acquisition trainings in sessions S2 and S3. When the rats were subjected to the extinction sessions after a break for consolidation, the conditioned response (CR was also significantly higher in the DHA-administered rats. Interestingly, the freezing responses (frequency and time also significantly decreased in the DHA-administered rats, thus

  20. Formal description of the OSI session layer: session service

    NARCIS (Netherlands)

    van Sinderen, Marten J.; van Eijk, P.H.J.; Vissers, C.A.; Diaz, M.

    1989-01-01

    The LOTOS formal description of the OSI session service is presented on basis of specification samples from the full description, giving account of how specification styles and session service architectural elements are reflected in the description. Both information (data types) and process

  1. Extinction of Conditioned Responses to Methamphetamine-Associated Stimuli in Healthy Humans.

    Science.gov (United States)

    Cavallo, Joel S; Ruiz, Nicholas A; de Wit, Harriet

    2016-07-01

    Contextual stimuli present during drug experiences become associated with the drug through Pavlovian conditioning and are thought to sustain drug-seeking behavior. Thus, extinction of conditioned responses is an important target for treatment. To date, acquisition and extinction to drug-paired cues have been studied in animal models or drug-dependent individuals, but rarely in non-drug users. We have recently developed a procedure to study acquisition of conditioned responses after single doses of methamphetamine (MA) in healthy volunteers. Here, we examined extinction of these responses and their persistence after conditioning. Healthy adults (18-35 years; N = 20) received two pairings of audio-visual stimuli with MA (20 mg oral) or placebo. Responses to stimuli were assessed before and after conditioning, using three tasks: behavioral preference, attentional bias, and subjective "liking." Subjects exhibited behavioral preference for the drug-paired stimuli at the first post-conditioning test, but this declined rapidly on subsequent extinction tests. They also exhibited a bias to initially look towards the drug-paired stimuli at the first post-test session, but not thereafter. Subjects who experienced more positive subjective drug effects during conditioning exhibited a smaller decline in preference during the extinction phase. Further, longer inter-session intervals during the extinction phase were associated with less extinction of the behavioral preference measure. Conditioned responses after two pairings with MA extinguish quickly, and are influenced by both subjective drug effects and the extinction interval. Characterizing and refining this conditioning procedure will aid in understanding the acquisition and extinction processes of drug-related conditioned responses in humans.

  2. Post-Learning Sleep Transiently Boosts Context Specific Operant Extinction Memory

    Directory of Open Access Journals (Sweden)

    Marion Inostroza

    2017-04-01

    Full Text Available Operant extinction is learning to supress a previously rewarded behavior. It is known to be strongly associated with the specific context in which it was acquired, which limits the therapeutic use of operant extinction in behavioral treatments, e.g., of addiction. We examined whether sleep influences contextual memory of operant extinction over time, using two different recall tests (Recent and Remote. Rats were trained in an operant conditioning task (lever press in context A, then underwent extinction training in context B, followed by a 3-h retention period that contained either spontaneous morning sleep, morning sleep deprivation, or spontaneous evening wakefulness. A recall test was performed either immediately after the 3-h experimental retention period (Recent recall or after 48 h (Remote, in the extinction context B and in a novel context C. The two main findings were: (i at the Recent recall test, sleep in comparison with sleep deprivation and spontaneous wakefulness enhanced extinction memory but, only in the extinction context B; (ii at the Remote recall, extinction performance after sleep was enhanced in both contexts B and C to an extent comparable to levels at Recent recall in context B. Interestingly, extinction performance at Remote recall was also improved in the sleep deprivation groups in both contexts, with no difference to performance in the sleep group. Our results suggest that 3 h of post-learning sleep transiently facilitate the context specificity of operant extinction at a Recent recall. However, the improvement and contextual generalization of operant extinction memory observed in the long-term, i.e., after 48 h, does not require immediate post-learning sleep.

  3. Extinction learning is slower, weaker and less context specific after alcohol.

    Science.gov (United States)

    Bisby, James A; King, John A; Sulpizio, Valentina; Degeilh, Fanny; Valerie Curran, H; Burgess, Neil

    2015-11-01

    Alcohol is frequently involved in psychological trauma and often used by individuals to reduce fear and anxiety. We examined the effects of alcohol on fear acquisition and extinction within a virtual environment. Healthy volunteers were administered alcohol (0.4g/kg) or placebo and underwent acquisition and extinction from different viewpoints of a virtual courtyard, in which the conditioned stimulus, paired with a mild electric shock, was centrally located. Participants returned the following day to test fear recall from both viewpoints of the courtyard. Skin conductance responses were recorded as an index of conditioned fear. Successful fear acquisition under alcohol contrasted with impaired extinction learning evidenced by persistent conditioned responses (Experiment 1). Participants' impairments in extinction under alcohol correlated with impairments in remembering object-locations in the courtyard seen from one viewpoint when tested from the other viewpoint. Alcohol-induced extinction impairments were overcome by increasing the number of extinction trials (Experiment 2). However, a test of fear recall the next day showed persistent fear in the alcohol group across both viewpoints. Thus, alcohol impaired extinction rather than acquisition of fear, suggesting that extinction is more dependent than acquisition on alcohol-sensitive representations of spatial context. Overall, extinction learning under alcohol was slower, weaker and less context-specific, resulting in persistent fear at test that generalized to the extinction viewpoint. The selective effect on extinction suggests an effect of alcohol on prefrontal involvement, while the reduced context-specificity implicates the hippocampus. These findings have important implications for the use of alcohol by individuals with clinical anxiety disorders. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  4. Extensive Extinction in Multiple Contexts Eliminates the Renewal of Conditioned Fear in Rats

    Science.gov (United States)

    Thomas, Brian L.; Vurbic, Drina; Novak, Cheryl

    2009-01-01

    Two studies examined whether nonreinforcement of a stimulus in multiple contexts, instead of a single context, would decrease renewal of conditioned fear in rats (as assessed by conditioned suppression of lever pressing). In Experiment 1, renewal was measured after 36 nonreinforced CS trials delivered during six extinction sessions in a single…

  5. Fear extinction deficits following acute stress associate with increased spine density and dendritic retraction in basolateral amygdala neurons.

    Science.gov (United States)

    Maroun, Mouna; Ioannides, Pericles J; Bergman, Krista L; Kavushansky, Alexandra; Holmes, Andrew; Wellman, Cara L

    2013-08-01

    Stress-sensitive psychopathologies such as post-traumatic stress disorder are characterized by deficits in fear extinction and dysfunction of corticolimbic circuits mediating extinction. Chronic stress facilitates fear conditioning, impairs extinction, and produces dendritic proliferation in the basolateral amygdala (BLA), a critical site of plasticity for extinction. Acute stress impairs extinction, alters plasticity in the medial prefrontal cortex-to-BLA circuit, and causes dendritic retraction in the medial prefrontal cortex. Here, we examined extinction learning and basolateral amygdala pyramidal neuron morphology in adult male rats following a single elevated platform stress. Acute stress impaired extinction acquisition and memory, and produced dendritic retraction and increased mushroom spine density in basolateral amygdala neurons in the right hemisphere. Unexpectedly, irrespective of stress, rats that underwent fear and extinction testing showed basolateral amygdala dendritic retraction and altered spine density relative to non-conditioned rats, particularly in the left hemisphere. Thus, extinction deficits produced by acute stress are associated with increased spine density and dendritic retraction in basolateral amygdala pyramidal neurons. Furthermore, the finding that conditioning and extinction as such was sufficient to alter basolateral amygdala morphology and spine density illustrates the sensitivity of basolateral amygdala morphology to behavioral manipulation. These findings may have implications for elucidating the role of the amygdala in the pathophysiology of stress-related disorders. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

  6. The extinction of the dinosaurs.

    Science.gov (United States)

    Brusatte, Stephen L; Butler, Richard J; Barrett, Paul M; Carrano, Matthew T; Evans, David C; Lloyd, Graeme T; Mannion, Philip D; Norell, Mark A; Peppe, Daniel J; Upchurch, Paul; Williamson, Thomas E

    2015-05-01

    Non-avian dinosaurs went extinct 66 million years ago, geologically coincident with the impact of a large bolide (comet or asteroid) during an interval of massive volcanic eruptions and changes in temperature and sea level. There has long been fervent debate about how these events affected dinosaurs. We review a wealth of new data accumulated over the past two decades, provide updated and novel analyses of long-term dinosaur diversity trends during the latest Cretaceous, and discuss an emerging consensus on the extinction's tempo and causes. Little support exists for a global, long-term decline across non-avian dinosaur diversity prior to their extinction at the end of the Cretaceous. However, restructuring of latest Cretaceous dinosaur faunas in North America led to reduced diversity of large-bodied herbivores, perhaps making communities more susceptible to cascading extinctions. The abruptness of the dinosaur extinction suggests a key role for the bolide impact, although the coarseness of the fossil record makes testing the effects of Deccan volcanism difficult. © 2014 The Authors. Biological Reviews © 2014 Cambridge Philosophical Society.

  7. Flood basalts and extinction events

    Science.gov (United States)

    Stothers, Richard B.

    1993-01-01

    The largest known effusive eruptions during the Cenozoic and Mesozoic Eras, the voluminous flood basalts, have long been suspected as being associated with major extinctions of biotic species. Despite the possible errors attached to the dates in both time series of events, the significance level of the suspected correlation is found here to be 1 percent to 4 percent. Statistically, extinctions lag eruptions by a mean time interval that is indistinguishable from zero, being much less than the average residual derived from the correlation analysis. Oceanic flood basalts, however, must have had a different biological impact, which is still uncertain owing to the small number of known examples and differing physical factors. Although not all continental flood basalts can have produced major extinction events, the noncorrelating eruptions may have led to smaller marine extinction events that terminated at least some of the less catastrophically ending geologic stages. Consequently, the 26 Myr quasi-periodicity seen in major marine extinctions may be only a sampling effect, rather than a manifestation of underlying periodicity.

  8. Erasing fear memories with extinction training.

    Science.gov (United States)

    Quirk, Gregory J; Paré, Denis; Richardson, Rick; Herry, Cyril; Monfils, Marie H; Schiller, Daniela; Vicentic, Aleksandra

    2010-11-10

    Decades of behavioral studies have confirmed that extinction does not erase classically conditioned fear memories. For this reason, research efforts have focused on the mechanisms underlying the development of extinction-induced inhibition within fear circuits. However, recent studies in rodents have uncovered mechanisms that stabilize and destabilize fear memories, opening the possibility that extinction might be used to erase fear memories. This symposium focuses on several of these new developments, which involve the timing of extinction training. Extinction-induced erasure of fear occurs in very young rats, but is lost with the development of perineuronal nets in the amygdala that render fear memories impervious to extinction. Moreover, extinction administered during the reconsolidation phase, when fear memory is destabilized, updates the fear association as safe, thereby preventing the return of fear, in both rats and humans. The use of modified extinction protocols to eliminate fear memories complements existing pharmacological strategies for strengthening extinction.

  9. Memory extinction entails the inhibition of the transcription factor NF-kappaB.

    Directory of Open Access Journals (Sweden)

    Emiliano Merlo

    Full Text Available In contextual memories, an association between a positive or negative reinforcement and the contextual cues where the reinforcement occurs is formed. The re-exposure to the context without reinforcement can lead to memory extinction or reconsolidation, depending on the number of events or duration of a single event of context re-exposure. Extinction involves the temporary waning of the previously acquired conditioned response. The molecular processes underlying extinction and the mechanisms which determine if memory will reconsolidate or extinguish after retrieval are not well characterized, particularly the role of transcription factors and gene expression. Here we studied the participation of a transcription factor, NF-kappaB, in memory extinction. In the crab context-signal memory, the activation of NF-kappaB plays a critical role in consolidation and reconsolidation, memory processes that are well characterized in this model. The administration of a NF-kappaB inhibitor, sulfasalazine prior to extinction session impeded spontaneous recovery. Moreover, reinstatement experiments showed that the original memory was not affected and that NF-kappaB inhibition by sulfasalazine impaired spontaneous recovery strengthening the ongoing memory extinction process. Interestingly, in animals with fully consolidated memory, a brief re-exposure to the training context induced neuronal NF-kappaB activation and reconsolidation, while prolonged re-exposure induced NF-kappaB inhibition and memory extinction. These data constitutes a novel insight into the molecular mechanisms involved in the switch between memory reconsolidation and extinction. Moreover, we propose the inhibition of NF-kappaB as the engaged mechanism underlying extinction, supporting a novel approach for the pharmacological enhancement of this memory process. The accurate description of the molecular mechanisms that support memory extinction is potentially useful for developing new strategies

  10. Interstellar extinction in the infrared

    International Nuclear Information System (INIS)

    Draine, B.T.

    1989-01-01

    Extinction by insterstellar dust at infrared wavelengths is reviewed. For 0.7 λ proportional to λ -1.75 , although the observational uncertainties remain appreciable. In the 8-30 μ m region interstellar extinction is dominated by the 9.7 μ m and 18 μ m silicate features; the absolute strength (relative to the continuum extinction at shorter wavelengths), the detailed wavelength-dependence of these features, and the possible variation of the profile shape from diffuse clouds to dense clouds, all remain somewhat controversial. In the farinfrared λ > ∼ 30 μ m grain emissivity estimates by different authors vary considerably; future observations of thermal emission from diffuse clouds in the 300 μ m region offer the prospect of substantially reducing uncertainties in far-infrared emissivities

  11. Infectious Disease, Endangerment, and Extinction

    Science.gov (United States)

    MacPhee, Ross D. E.; Greenwood, Alex D.

    2013-01-01

    Infectious disease, especially virulent infectious disease, is commonly regarded as a cause of fluctuation or decline in biological populations. However, it is not generally considered as a primary factor in causing the actual endangerment or extinction of species. We review here the known historical examples in which disease has, or has been assumed to have had, a major deleterious impact on animal species, including extinction, and highlight some recent cases in which disease is the chief suspect in causing the outright endangerment of particular species. We conclude that the role of disease in historical extinctions at the population or species level may have been underestimated. Recent methodological breakthroughs may lead to a better understanding of the past and present roles of infectious disease in influencing population fitness and other parameters. PMID:23401844

  12. [Posttrial injections of corticosterone in dorsal hippocampus of the BALB/c mouse facilitate extinction of appetitive operant conditioning in the Skinner box].

    Science.gov (United States)

    Micheau, J; Destrade, C; Soumireu-Mourat, B

    1982-06-28

    Corticosterone was injected bilaterally into the dorsal hippocampus of BALB/c Mice immediately after the first extinction session of an operant conditioning in a Skinner box. Compared with the control animals the Mice that received 1 or 0.1 microgram corticosterone exhibited 24 hrs. later, faster extinction of this conditioning. With a 0.01 microgram dose of corticosterone in each hippocampus we obtained an accelerated extinction during the session. These data suggest that corticosterone modulates hippocampal mechanisms involved in memory processes.

  13. Negative appraisals and fear extinction are independently related to PTSD symptoms.

    Science.gov (United States)

    Zuj, Daniel V; Palmer, Matthew A; Gray, Kate E; Hsu, Chia-Ming K; Nicholson, Emma L; Malhi, Gin S; Bryant, Richard A; Felmingham, Kim L

    2017-08-01

    Considerable research has revealed impaired fear extinction to be a significant predictor of PTSD. Fear extinction is also considered the primary mechanism of exposure therapy, and a critical factor in PTSD recovery. The cognitive theory of PTSD proposes that symptoms persist due to excessive negative appraisals about the trauma and its sequelae. Research has not yet examined the relationship between fear extinction and negative appraisals in PTSD. A cross-sectional sample of participants with PTSD (n =21), and trauma-exposed controls (n =33) underwent a standardized differential fear conditioning and extinction paradigm, with skin conductance response (SCR) amplitude serving as the index of conditioned responses. The Posttraumatic Cognitions Inventory (PTCI) was used to index catastrophic negative appraisals. Participants with PTSD demonstrated a slower decrease in overall SCR responses during extinction and greater negative appraisals compared to the group. A moderation analysis revealed that both negative trauma-relevant appraisals and fear extinction learning were independently associated with PTSD symptoms, but there was no moderation interaction. The current study was limited by a modest sample size, leading to the inclusion of participants with subclinical PTSD symptoms. Further, the current study only assessed fear extinction learning; including a second day extinction recall task may show alternative effects. These findings indicate that negative appraisals and fear extinction did not interact, but had independent relationships with PTSD symptoms. Here we show for the first time in an experimental framework that negative appraisals and fear extinction play separate roles in PTSD symptoms. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Reclaiming Hope in Extinction Storytelling.

    Science.gov (United States)

    Kohl, Patrice

    2017-07-01

    Critics often take conservationists to task for delivering a constant barrage of bad news without offering a compelling vision of the future. Could recent advances in synthetic biology-an optimistic, forward-looking field with a can-do attitude-let conservationists develop a new vision and generate some better news? Synthetic biology and related gene-editing applications could be used to address threats to species. Genetic interventions might also be used in plants to better protect biodiversity in U.S. rangelands and forests. One possibility has stood out in its ability to capture media attention and the public imagination-recreating extinct species. And perhaps a de-extinction story could counter the seemingly relentless negativity in biodiversity talk. De-extinction proponent Stewart Brand writes that resurrecting species could shift the "conservation story … from negative to positive, from constant whining and guilt-tripping to high fives and new excitement." So, why do many people in conservation oppose the de-extinction narrative? This essay is an inquiry into whether there are intrinsic social reactions to these types of conservation solutions that might offset their potential benefits. If genetic tools are to be applied to address conservation issues in a realistic and responsible way, their broader social-cultural implications deserve far more attention than they have so far received. © 2017 The Hastings Center.

  15. Extinction debt on oceanic islands

    DEFF Research Database (Denmark)

    Triantis, Kostas A.; Borges, Paulo A. V.; Ladle, Richard J.

    2010-01-01

    the magnitude of such future extinction events has been hampered by potentially inaccurate assumptions about the slope of species-area relationships, which are habitat- and taxon-specific. We overcome this challenge by applying a method that uses the historical sequence of deforestation in the Azorean Islands...

  16. Repeated Acquisitions and Extinctions in Classical Conditioning of the Rabbit Nictitating Membrane Response

    Science.gov (United States)

    Kehoe, E. James

    2006-01-01

    The rabbit nictitating membrane (NM) response underwent successive stages of acquisition and extinction training in both delay (Experiment 1) and trace (Experiment 2) classical conditioning. In both cases, successive acquisitions became progressively faster, although the largest, most reliable acceleration occurred between the first and second…

  17. An investigation of the interstellar extinction

    International Nuclear Information System (INIS)

    Roche, P.F.; Aitken, D.K.; Melbourne Univ., Point Cook

    1984-01-01

    The 10 μm extinction towards six WC8 or WC9 Wolf-Rayet stars is investigated. All objects show smooth dust emission suffering silicate absorption with depths well correlated with the extinction in the visible. The de-reddened spectra are well represented by emission from featureless grain components, possibly from iron or carbon grains. The extinction to the stars is found to be dominantly interstellar in origin with little extinction from the circumstellar shell. (author)

  18. Outpatient single-session yttrium-90 glass microsphere radioembolization.

    Science.gov (United States)

    Gates, Vanessa L; Marshall, Karen G; Salzig, Krystina; Williams, Melissa; Lewandowski, Robert J; Salem, Riad

    2014-02-01

    To investigate the feasibility of yttrium-90 ((90)Y) glass microsphere radioembolization (including angiography, lung shunt assessment, and treatment) as a single-session, outpatient procedure. Between January 2008 and June 2013, 14 patients underwent outpatient, single-session radioembolization with (90)Y glass microspheres. As part of the routine diagnostic work-up, all patients underwent either computed tomography (CT) or magnetic resonance imaging of the liver with three-dimensional analysis and had laboratory results forwarded to our center for confirmation of candidacy before treatment. On treatment day, all patients underwent planning mesenteric angiography with flat panel cone-beam CT imaging. Patients were administered 33-85 MBq of technetium-99m macroaggregated albumin ((99m)Tc-MAA) via a microcatheter positioned in a hepatic artery supplying the tumor of interest. Planar scintigraphy was initiated within 2 hours after the administration of (99m)Tc-MAA and lung shunt fraction was determined. Final dosimetry calculations were performed while the patient was being transferred back from nuclear medicine to interventional radiology. All patients successfully underwent planning angiography with administration of (99m)Tc-MAA and (90)Y radioembolization as a single-session treatment. There were no reportable or recordable medical events; treatment was carried out to the desired dose in all cases. The mean total procedure time was 2.70 hours ± 0.72 (range, 1.63-3.97 h). This study reports a novel proof of concept for performing radioembolization in a single-session setting. By using the described method, time between initial clinical assessments and radioembolization treatment is decreased, and costs are minimized. © 2014 Published by SIR on behalf of SIR.

  19. Further Evidence of Auditory Extinction in Aphasia

    Science.gov (United States)

    Marshall, Rebecca Shisler; Basilakos, Alexandra; Love-Myers, Kim

    2013-01-01

    Purpose: Preliminary research ( Shisler, 2005) suggests that auditory extinction in individuals with aphasia (IWA) may be connected to binding and attention. In this study, the authors expanded on previous findings on auditory extinction to determine the source of extinction deficits in IWA. Method: Seventeen IWA (M[subscript age] = 53.19 years)…

  20. Global Implications of late Pleistocene Megafaunal Extinctions in the Holarctic

    Science.gov (United States)

    Cooper, Alan; Turney, Chris

    2017-04-01

    Improved resolution data from radiocarbon, climate and ancient DNA studies of megafauna and humans is providing the first ability to disentangle the roles of climate change and human impact in the Late Pleistocene megafaunal extinctions. In the Holarctic we find that megafaunal populations underwent repeated local or global extinctions apparently associated with abrupt, centennial to millennial duration warming events (Dansgaard-Oeschger interstadials). Importantly, the extinction events took place both before and after the arrival of modern humans in the landscape. Here we look at the possible role of human activity in Holarctic and suggest it may be through the disruption of metapopulation processes which stabilize ecosystems and may have evolved to provide resilience to rapid and frequent climate shifts in the past. The observed relationship between climate and humans on megafaunal populations may provide a model for global extinction. Fortunately in this regard, the rapid movement of the first Native Americans throughout both American continents during the Last Deglaciation provides a powerful and unique model system for testing the competing roles on extinction because the opposing climate trends in each hemisphere at the time. Here we show that while megafaunal extinctions were associated with warming trends in both cases, the out-of-phase climate patterns caused the sequence and timing of events to be mirrored, providing a unique high-resolution view of the interactions of human colonization and rapid climate change on megafaunal ecosystems, with implications for future warming scenarios. References: Cooper, A., Turney, C., Hughen, K.A., Brook, B.W., McDonald, H.G., Bradshaw, C.J.A., 2015. Abrupt warming events drove Late Pleistocene Holarctic megafaunal turnover. Science 349, 602-606. Metcalf, J.L., Turney, C., Barnett, R., Martin, F., Bray, S.C., Vilstrup, J.T., Orlando, L., Salas-Gismondi, R., Loponte, D., Medina, M., De Nigris, M., Civalero, T., Fern

  1. Human Reliability Analysis: session summary

    International Nuclear Information System (INIS)

    Hall, R.E.

    1985-01-01

    The use of Human Reliability Analysis (HRA) to identify and resolve human factors issues has significantly increased over the past two years. Today, utilities, research institutions, consulting firms, and the regulatory agency have found a common application of HRA tools and Probabilistic Risk Assessment (PRA). The ''1985 IEEE Third Conference on Human Factors and Power Plants'' devoted three sessions to the discussion of these applications and a review of the insights so gained. This paper summarizes the three sessions and presents those common conclusions that were discussed during the meeting. The paper concludes that session participants supported the use of an adequately documented ''living PRA'' to address human factors issues in design and procedural changes, regulatory compliance, and training and that the techniques can produce cost effective qualitative results that are complementary to more classical human factors methods

  2. The effect of geographic range on extinction risk during background and mass extinction

    OpenAIRE

    Payne, Jonathan L.; Finnegan, Seth

    2007-01-01

    Wide geographic range is generally thought to buffer taxa against extinction, but the strength of this effect has not been investigated for the great majority of the fossil record. Although the majority of genus extinctions have occurred between major mass extinctions, little is known about extinction selectivity regimes during these “background” intervals. Consequently, the question of whether selectivity regimes differ between background and mass extinctions is largely unresolved. Using log...

  3. [Facilitation of the retention and acceleration of operant conditioning extinction after cingulate cortex lesions in BALB/c mice].

    Science.gov (United States)

    Destrade, C; Gauthier, M

    1981-12-21

    One week after receiving bilateral electrolytic lesions of the cingulate cortex, BALB/c Mice underwent acquisition, retention and extinction of an appetitive operant-conditioning task in a Skinner box. There was no significant difference between lesioned and control animals in acquisition; however, lesioned mice exhibited improved retention and faster extinction. These results suggest a possible involvement of the cingulate cortex in memory processes.

  4. Environmental trends in extinction during the Paleozoic

    Science.gov (United States)

    Sepkoski, J. John, Jr.

    1987-01-01

    Extinction intensities calculated from 505 Paleozoic marine assemblages divided among six environmental zones and 40 stratigraphic intervals indicate that whole communities exhibit increasing extinction offshore but that genera within individual taxonomic classes tend to have their highest extinction onshore. The offshore trend at the community level results from a concentration of genera in classes with low characteristic extinction rates in nearshore environments. This finding is consistent with the ecologic expectation that organisms inhabiting unpredictably fluctuating environments should suffer more extinction than counterparts living under more predictably equitable conditions.

  5. Sessions and Separability in Security Protocols

    DEFF Research Database (Denmark)

    Carbone, Marco; Guttman, Joshua

    2013-01-01

    Despite much work on sessions and session types in non- adversarial contexts, session-like behavior given an active adversary has not received an adequate definition and proof methods. We provide a syntactic property that guarantees that a protocol has session-respecting executions. Any uncomprom......Despite much work on sessions and session types in non- adversarial contexts, session-like behavior given an active adversary has not received an adequate definition and proof methods. We provide a syntactic property that guarantees that a protocol has session-respecting executions. Any...

  6. Extinction risk escalates in the tropics.

    Directory of Open Access Journals (Sweden)

    Jana C Vamosi

    Full Text Available The latitudinal biodiversity gradient remains one of the most widely recognized yet puzzling patterns in nature. Presently, the high level of extinction of tropical species, referred to as the "tropical biodiversity crisis", has the potential to erode this pattern. While the connection between species richness, extinction, and speciation has long intrigued biologists, these interactions have experienced increased poignancy due to their relevancy to where we should concentrate our conservation efforts. Natural extinction is a phenomenon thought to have its own latitudinal gradient, with lower extinction rates in the tropics being reported in beetles, birds, mammals, and bivalves. Processes that have buffered ecosystems from high extinction rates in the past may also buffer ecosystems against disturbance of anthropogenic origin. While potential parallels between historical and present-day extinction patterns have been acknowledged, they remain only superficially explored and plant extinction patterns have been particularly neglected. Studies on the disappearances of animal species have reached conflicting conclusions, with the rate of extinction appearing either higher or lower in species richness hotspots. Our global study of extinction risk in vascular plants finds disproportionately higher extinction risk in tropical countries, even when indicators of human pressure (GDP, population density, forest cover change are taken into account. Our results are at odds with the notion that the tropics represent a museum of plant biodiversity (places of historically lowered extinction and we discuss mechanisms that may reconcile this apparent contradiction.

  7. Acute gonadotropin-releasing hormone agonist treatment enhances extinction memory in male rats.

    Science.gov (United States)

    Maeng, L Y; Taha, M B; Cover, K K; Glynn, S S; Murillo, M; Lebron-Milad, K; Milad, M R

    2017-08-01

    Leuprolide acetate (LEU), also known as Lupron, is commonly used to treat prostate cancer in men. As a gonadotropin-releasing hormone (GnRH) receptor agonist, it initially stimulates the release of gonadal hormones, testosterone (T) and estradiol. This surge eventually suppresses these hormones, preventing the further growth and spread of cancer cells. Individuals receiving this treatment often report anxiety and cognitive changes, but LEU's effects on the neural mechanisms that are involved in anxiety during the trajectory of treatment are not well known. In this study, we examined the acute effects of LEU on fear extinction, hypothesizing that increased T levels following a single administration of LEU will facilitate extinction recall by altering neuronal activity within the fear extinction circuitry. Two groups of naïve adult male rats underwent a 3-day fear conditioning, extinction, and recall experiment. The delayed group (n=15) received a single injection of vehicle or LEU (1.2mg/kg) 3weeks before behavioral testing. The acute group (n=25) received an injection one day after fear conditioning, 30min prior to extinction training. Following recall, the brains for all animals were collected for c-fos immunohistochemistry. Blood samples were also collected and assayed for T levels. Acute administration of LEU increased serum T levels during extinction training and enhanced extinction recall 24h later. This enhanced extinction memory was correlated with increased c-fos activity within the infralimbic cortex and amygdala, which was not observed in the delayed group. These results suggest that the elevation in T induced by acute administration of LEU can influence extinction memory consolidation, perhaps through modification of neuronal activity within the infralimbic cortex and amygdala. This may be an important consideration in clinical applications of LEU and its effects on anxiety and cognition. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Combining D-cycloserine with appetitive extinction learning modulates amygdala activity during recall.

    Science.gov (United States)

    Ebrahimi, Claudia; Koch, Stefan P; Friedel, Eva; Crespo, Ilsoray; Fydrich, Thomas; Ströhle, Andreas; Heinz, Andreas; Schlagenhauf, Florian

    2017-07-01

    Appetitive Pavlovian conditioning plays a crucial role in the pathogenesis of drug addiction and conditioned reward cues can trigger craving and relapse even after long phases of abstinence. Promising preclinical work showed that the NMDA-receptor partial agonist D-cycloserine (DCS) facilitates Pavlovian extinction learning of fear and drug cues. Furthermore, DCS-augmented exposure therapy seems to be beneficial in various anxiety disorders, while the supposed working mechanism of DCS during human appetitive or aversive extinction learning is still not confirmed. To test the hypothesis that DCS administration before extinction training improves extinction learning, healthy adults (n=32) underwent conditioning, extinction, and extinction recall on three successive days in a randomized, double-blind, placebo-controlled fMRI design. Monetary wins and losses served as unconditioned stimuli during conditioning to probe appetitive and aversive learning. An oral dose of 50mg of DCS or placebo was administered 1h before extinction training and DCS effects during extinction recall were evaluated on a behavioral and neuronal level. We found attenuated amygdala activation in the DCS compared to the placebo group during recall of the extinguished appetitive cue, along with evidence for enhanced functional amygdala-vmPFC coupling in the DCS group. While the absence of additional physiological measures of conditioned responses during recall in this study prevent the evaluation of a behavioral DCS effect, our neuronal findings are in accordance with recent theories linking successful extinction recall in humans to modulatory top-down influences from the vmPFC that inhibit amygdala activation. Our results should encourage further translational studies concerning the usefulness of DCS to target maladaptive Pavlovian reward associations. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. Extinction Coefficient of Gold Nanostars.

    Science.gov (United States)

    de Puig, Helena; Tam, Justina O; Yen, Chun-Wan; Gehrke, Lee; Hamad-Schifferli, Kimberly

    2015-07-30

    Gold nanostars (NStars) are highly attractive for biological applications due to their surface chemistry, facile synthesis and optical properties. Here, we synthesize NStars in HEPES buffer at different HEPES/Au ratios, producing NStars of different sizes and shapes, and therefore varying optical properties. We measure the extinction coefficient of the synthesized NStars at their maximum surface plasmon resonances (SPR), which range from 5.7 × 10 8 to 26.8 × 10 8 M -1 cm -1 . Measured values correlate with those obtained from theoretical models of the NStars using the discrete dipole approximation (DDA), which we use to simulate the extinction spectra of the nanostars. Finally, because NStars are typically used in biological applications, we conjugate DNA and antibodies to the NStars and calculate the footprint of the bound biomolecules.

  10. A novel UCS memory retrieval-extinction procedure to inhibit relapse to drug seeking

    Science.gov (United States)

    Luo, Yi-xiao; Xue, Yan-xue; Liu, Jian-feng; Shi, Hai-shui; Jian, Min; Han, Ying; Zhu, Wei-li; Bao, Yan-ping; Wu, Ping; Ding, Zeng-bo; Shen, Hao-wei; Shi, Jie; Shaham, Yavin; Lu, Lin

    2015-01-01

    We recently reported that a conditioned stimulus (CS) memory retrieval-extinction procedure decreases reinstatement of cocaine and heroin seeking in rats and heroin craving in humans. Here we show that non-contingent cocaine or methylphenidate injections (UCS retrieval) 1 h before the extinction sessions decreases cocaine-priming-induced reinstatement, spontaneous recovery, and renewal of cocaine seeking in rats. Unlike the CS-based memory retrieval-extinction procedure, the UCS memory retrieval manipulation decreases renewal and reinstatement of cocaine seeking in the presence of cocaine cues that were not present during extinction training and also decreases cocaine seeking when the procedure commences after 28 days of abstinence. The inhibitory effect of the UCS retrieval manipulation on cocaine-priming-induced reinstatement is mediated by regulation of AMPA-receptor endocytosis in the basolateral amygdala. The UCS memory retrieval-extinction procedure has superior relapse prevention characteristics than the CS memory retrieval-extinction procedure and could be a promising method for decreasing relapse in human addicts. PMID:26169171

  11. Prefrontal-Amygdala Connectivity and State Anxiety during Fear Extinction Recall in Adolescents

    Directory of Open Access Journals (Sweden)

    Despina E. Ganella

    2017-12-01

    Full Text Available While deficits in fear extinction recall have been suggested to underlie vulnerability to anxiety disorders in adolescents, the neurobiology of these deficits remain underexplored. Here we investigate the functional connectivity (FC of the ventromedial prefrontal cortex (vmPFC and dorsolateral PFC (dlPFC underlying extinction recall in healthy adolescents, and assess associations between FC and state/trait anxiety. Adolescents (17 and adults (14, for comparison completed a fear-learning paradigm involving extinction and extinction recall during a functional magnetic resonance imaging session, in which skin conductance response (SCR was recorded. Psychophysiological interaction analyses revealed that during extinction recall there was significant negative connectivity between the vmPFC and amygdala in adults, but not adolescents. vmPFC-amygdala connectivity was positively correlated with SCR. Adolescents showed significant negative FC between the dlPFC and the left and right hippocampus, and the amygdala, which was positively correlated with state anxiety. Recall was also associated with negative connectivity between the dlPFC and thalamus, posterior cingulate cortex, fusiform gyrus, and pallidum in adolescents. These results demonstrate that fear extinction recall in healthy adolescents is associated with FC between prefrontal and limbic brain regions, and suggest that alterations in connectivity may be associated with vulnerability to anxiety in adolescence.

  12. Brain functional network changes following Prelimbic area inactivation in a spatial memory extinction task.

    Science.gov (United States)

    Méndez-Couz, Marta; Conejo, Nélida M; Vallejo, Guillermo; Arias, Jorge L

    2015-01-01

    Several studies suggest a prefrontal cortex involvement during the acquisition and consolidation of spatial memory, suggesting an active modulating role at late stages of acquisition processes. Recently, we have reported that the prelimbic and infralimbic areas of the prefrontal cortex, among other structures, are also specifically involved in the late phases of spatial memory extinction. This study aimed to evaluate whether the inactivation of the prelimbic area of the prefrontal cortex impaired spatial memory extinction. For this purpose, male Wistar rats were implanted bilaterally with cannulae into the prelimbic region of the prefrontal cortex. Animals were trained during 5 consecutive days in a hidden platform task and tested for reference spatial memory immediately after the last training session. One day after completing the training task, bilateral infusion of the GABAA receptor agonist Muscimol was performed before the extinction protocol was carried out. Additionally, cytochrome c oxidase histochemistry was applied to map the metabolic brain activity related to the spatial memory extinction under prelimbic cortex inactivation. Results show that animals acquired the reference memory task in the water maze, and the extinction task was successfully completed without significant impairment. However, analysis of the functional brain networks involved by cytochrome oxidase activity interregional correlations showed changes in brain networks between the group treated with Muscimol as compared to the saline-treated group, supporting the involvement of the mammillary bodies at a the late stage in the memory extinction process. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. A phosphodiesterase 4-controlled switch between memory extinction and strengthening in the hippocampus.

    Science.gov (United States)

    Roesler, Rafael; Reolon, Gustavo K; Maurmann, Natasha; Schwartsmann, Gilberto; Schröder, Nadja; Amaral, Olavo B; Valvassori, Samira; Quevedo, João

    2014-01-01

    Established fear-related memories can undergo phenomena such as extinction or reconsolidation when recalled. Extinction probably involves the creation of a new, competing memory trace that decreases fear expression, whereas reconsolidation can mediate memory maintenance, updating, or strengthening. The factors determining whether retrieval will initiate extinction, reconsolidation, or neither of these two processes include training intensity, duration of the retrieval session, and age of the memory. However, previous studies have not shown that the same behavioral protocol can be used to induce either extinction or reconsolidation and strengthening, depending on the pharmacological intervention used. Here we show that, within an experiment that leads to extinction in control rats, memory can be strengthened if rolipram, a selective inhibitor of phosphodiesterase type 4 (PDE4), is administered into the dorsal hippocampus immediately after retrieval. The memory-enhancing effect of rolipram lasted for at least 1 week, was blocked by the protein synthesis inhibitor anisomycin, and did not occur when drug administration was not paired with retrieval. These findings indicate that the behavioral outcome of memory retrieval can be pharmacologically switched from extinction to strengthening. The cAMP/protein kinase A (PKA) signaling pathway might be a crucial mechanism determining the fate of memories after recall.

  14. A phosphodiesterase 4-controlled switch between memory extinction and strengthening in the hippocampus

    Directory of Open Access Journals (Sweden)

    Rafael eRoesler

    2014-03-01

    Full Text Available Established fear-related memories can undergo phenomena such as extinction or reconsolidation when recalled. Extinction probably involves the creation of a new, competing memory trace that decreases fear expression, whereas reconsolidation can mediate memory maintenance, updating, or strengthening. The factors determining whether retrieval will initiate extinction, reconsolidation, or neither of these two processes, include training intensity, duration of the retrieval session, and age of the memory. However, previous studies have not shown that the same behavioral protocol can be used to induce either extinction or reconsolidation and strengthening, depending on the pharmacological intervention used. Here we show that, within an experiment that leads to extinction in control rats, memory can be strengthened if rolipram, a selective inhibitor of phosphodiesterase type 4 (PDE4, is administered into the dorsal hippocampus immediately after retrieval. The memory-enhancing effect of rolipram lasted for at least one week, was blocked by the protein synthesis inhibitor anisomycin, and did not occur when drug administration was not paired with retrieval. These findings indicate that the behavioral outcome of memory retrieval can be pharmacologically switched from extinction to strengthening. The cAMP/protein kinase A (PKA signaling pathway might be a crucial mechanism determining the fate of memories after recall.

  15. Extinction Coefficient of Gold Nanostars

    OpenAIRE

    de Puig, Helena; Tam, Justina O.; Yen, Chun-Wan; Gehrke, Lee; Hamad-Schifferli, Kimberly

    2015-01-01

    Gold nanostars (NStars) are highly attractive for biological applications due to their surface chemistry, facile synthesis and optical properties. Here, we synthesize NStars in HEPES buffer at different HEPES/Au ratios, producing NStars of different sizes and shapes, and therefore varying optical properties. We measure the extinction coefficient of the synthesized NStars at their maximum surface plasmon resonances (SPR), which range from 5.7 × 108 to 26.8 × 108 M−1cm−1. Measured values correl...

  16. [Extinction and Reconsolidation of Memory].

    Science.gov (United States)

    Zuzina, A B; Balaban, P M

    2015-01-01

    Retrieval of memory followed by reconsolidation can strengthen a memory, while retrieval followed by extinction results in a decrease of memory performance due to weakening of existing memory or formation of a competing memory. In our study we analyzed the behavior and responses of identified neurons involved in the network underlying aversive learning in terrestrial snail Helix, and made an attempt to describe the conditions in which the retrieval of memory leads either to extinction or reconsolidation. In the network underlying the withdrawal behavior, sensory neurons, premotor interneurons, motor neurons, and modulatory for this network serotonergic neurons are identified and recordings from representatives of these groups were made before and after aversive learning. In the network underlying feeding behavior, the premotor modulatory serotonergic interneurons and motor neurons involved in motor program of feeding are identified. Analysis of changes in neural activity after aversive learning showed that modulatory neurons of feeding behavior do not demonstrate any changes (sometimes a decrease of responses to food was observed), while responses to food in withdrawal behavior premotor interneurons changed qualitatively, from under threshold EPSPs to spike discharges. Using a specific for serotonergic neurons neurotoxin 5,7-DiHT it was shown previously that the serotonergic system is necessary for the aversive learning, but is not necessary for maintenance and retrieval of this memory. These results suggest that the serotonergic neurons that are necessary as part of a reinforcement for developing the associative changes in the network may be not necessary for the retrieval of memory. The hypothesis presented in this review concerns the activity of the "reinforcement" serotonergic neurons that is suggested to be the gate condition for the choice between extinction/reconsolidation triggered by memory retrieval: if these serotonergic neurons do not respond during the

  17. Summary of Educational Poster Session

    Science.gov (United States)

    1992-01-01

    The educational poster session provided a way of increasing the ordinarily limited time available for discussion of papers, while simultaneously making it easier to communicate visual materials not well suited to oral presentations. Poster presenters were available for 3 hours to discuss their displays. Poster presentations were divided into two categories: minority...

  18. After Smokestack Chasing. Plenary Session.

    Science.gov (United States)

    Appalachia, 1986

    1986-01-01

    Plenary session opening remarks by Appalachian Regional Commission Co-Chairman Winnifred Pizzano inform participants that the Region's future success depends on their ability to meet the challenge of change. Excerpts from four panelists' speeches address rapid social and economic changes in economic development activities at state and local…

  19. Extinction correction and synchrotron radiation

    International Nuclear Information System (INIS)

    Suortti, P.

    1983-01-01

    The primary extinction factor ysub(p) is defined as the ratio of the integrated reflection from a coherently diffracting domain to the integrated kinematical reflection from the same domain. When ysub(p) is larger than 0.5 it may be approximated by ysub(p)= exp[-(αdelta) 2 ], where α is about 0.5 and delta the average size of the coherent domain when measured in units of the extinction length Λ, delta = D/Λ. Transfer equations are applied to symmetrical Laue diffraction, and the reflectivity per unit length, sigma(epsilon) is solved from the measured reflecting ratio as a function of the rocking angle epsilon = theta -thetasub(B). Measurements with conventional x-ray sources are made on single crystal slabs of Be and Si using AgKβ, MoKα 1 and CuKα radiation. The primary extinction factor ysub(p)(epsilon) is solved from a point-by-point comparison of two measurements where the extinction length Λ is changed by varying the polarization and/or wavelength of the x-ray beam. The results show that primary and secondary extinction are strongly correlated, and that the customary assumption of independent size and orientation distributions of crystal mosaics is unjustified. The structure factors for Be and Si show close agreement with other recent measurements and calculations. The limitations of the method are discussed in length, particularly the effects of beam divergences and incoherence of the rays in the crystal. It is concluded that under typical experimental conditions the requirements of the theory are met. Practical limitations arising from the use of characteristic wavelengths and unpolarized radiation prohibit the use of the full potential of the method. The properties of a synchrotron radiation source are compared with a conventional x-ray source, and it is demonstrated that the experimental limitations can be removed by the use of synchrotron radiation. A diffraction experiment with synchrotron radiation is outlined, as well as generalization of the

  20. The Physics session at the ATLAS overview week

    CERN Multimedia

    Takai, H.

    The Physics session at the ATLAS overview week at Clermont-Ferrand will be certainly remembered by the presentation of Blaise Pascal's historical experiment repeat. And why not? He is the local hero and by the looks of his primitive measurements it does take a lot of guts to explain his results on the basis of air columns. He was also lucky that he did not have to simulate his results on modern day computers but used the Pascaline. Certainly a man ahead of his time. Of course that wasn't all. Surrounded by a chain of (luckily) extinct volcanoes, rolling hills, and superb views, Clermont-Ferrand provided the perfect backdrop for the physics discussions. It was once more seen that the physics of ATLAS is diverse and that it is healthy and doing well. Many people contributed to the success of the session. Fabiola started the session precisely at 14:00 with a summary of the most recent activities from the physics coordination. Somehow what got stuck in my mind was the very positive statistics on how many prese...

  1. Biological correlates of extinction risk in bats.

    Science.gov (United States)

    Jones, Kate E; Purvis, Andy; Gittleman, John L

    2003-04-01

    We investigated patterns and processes of extinction and threat in bats using a multivariate phylogenetic comparative approach. Of nearly 1,000 species worldwide, 239 are considered threatened by the International Union for Conservation of Nature and Natural Resources (IUCN) and 12 are extinct. Small geographic ranges and low wing aspect ratios are independently found to predict extinction risk in bats, which explains 48% of the total variance in IUCN assessments of threat. The pattern and correlates of extinction risk in the two bat suborders are significantly different. A higher proportion (4%) of megachiropteran species have gone extinct in the last 500 years than microchiropteran bats (0.3%), and a higher proportion is currently at risk of extinction (Megachiroptera: 34%; Microchiroptera: 22%). While correlates of microchiropteran extinction risk are the same as in the order as a whole, megachiropteran extinction is correlated more with reproductive rate and less with wing morphology. Bat extinction risk is not randomly distributed phylogenetically: closely related species have more similar levels of threat than would be expected if extinction risk were random. Given the unbalanced nature of the evolutionary diversification of bats, it is probable that the amount of phylogenetic diversity lost if currently threatened taxa disappear may be greater than in other clades with numerically more threatened species.

  2. Sessions and Separability in Security Protocols

    DEFF Research Database (Denmark)

    Carbone, Marco; Guttman, Joshua

    2013-01-01

    Despite much work on sessions and session types in non- adversarial contexts, session-like behavior given an active adversary has not received an adequate definition and proof methods. We provide a syntactic property that guarantees that a protocol has session-respecting executions. Any uncomprom...

  3. Inhibition of spontaneous recovery of fear by mGluR5 after prolonged extinction training.

    Directory of Open Access Journals (Sweden)

    Sheng-Chun Mao

    Full Text Available Fear behavior is vital for survival and involves learning contingent associations of non-threatening cues with aversive stimuli. In contrast, excessive levels of fear can be maladaptive and lead to anxiety disorders. Generally, extensive sessions of extinction training correlates with reduced spontaneous recovery. The molecular mechanisms underlying the long-term inhibition of fear recovery following repeated extinction training are not fully understood. Here we show that in rats, prolonged extinction training causes greater reduction in both fear-potentiated startle and spontaneous recovery. This effect was specifically blocked by metabotropic glutamate receptor 5 (mGluR5, but not by mGluR1 antagonists and by a protein synthesis inhibitor. Similar inhibition of memory recovery following prolonged extinction training was also observed in mice. In agreement with the instrumental role of mGluR5 in the prolonged inhibition of fear recovery, we found that FMR1-/- mice which exhibit enhanced mGluR5-mediated signaling exhibit lower spontaneous recovery of fear after extinction training than wild-type littermates. At the molecular level, we discovered that prolonged extinction training reversed the fear conditioning-induced increase in surface expression of GluR1, AMPA/NMDA ratio, postsynaptic density-95 (PSD-95 and synapse-associated protein-97 (SAP97. Accordingly, delivery of Tat-GluR2(3Y, a synthetic peptide that blocks AMPA receptor endocytosis, inhibited prolonged extinction training-induced inhibition of fear recovery. Together, our results demonstrate that prolonged extinction training results in the mGluR5-dependent long-term inhibition of fear recovery. This effect may involve the degradation of original memory and may explain the beneficial effects of prolonged exposure therapy for the treatment of phobias.

  4. The ethics of reviving long extinct species.

    Science.gov (United States)

    Sandler, Ronald

    2014-04-01

    There now appears to be a plausible pathway for reviving species that have been extinct for several decades, centuries, or even millennia. I conducted an ethical analysis of de-extinction of long extinct species. I assessed several possible ethical considerations in favor of pursuing de-extinction: that it is a matter of justice; that it would reestablish lost value; that it would create new value; and that society needs it as a conservation last resort. I also assessed several possible ethical arguments against pursuing de-extinction: that it is unnatural; that it could cause animal suffering; that it could be ecologically problematic or detrimental to human health; and that it is hubristic. There are reasons in favor of reviving long extinct species, and it can be ethically acceptable to do so. However, the reasons in favor of pursuing de-extinction do not have to do with its usefulness in species conservation; rather, they concern the status of revived species as scientific and technological achievements, and it would be ethically problematic to promote de-extinction as a significant conservation strategy, because it does not prevent species extinctions, does not address the causes of extinction, and could be detrimental to some species conservation efforts. Moreover, humanity does not have a responsibility or obligation to pursue de-extinction of long extinct species, and reviving them does not address any urgent problem. Therefore, legitimate ecological, political, animal welfare, legal, or human health concerns associated with a de-extinction (and reintroduction) must be thoroughly addressed for it to be ethically acceptable. © 2013 Society for Conservation Biology.

  5. Testing the effects of Δ9-THC and D-cycloserine on extinction of conditioned fear in humans

    Science.gov (United States)

    Klumpers, Floris; Denys, Damiaan; Kenemans, J Leon; Grillon, Christian; van der Aart, Jasper; Baas, Johanna MP

    2012-01-01

    Preclinical evidence implicates several neurotransmitter systems in the extinction of conditioned fear. These results are of great interest, because the reduction of acquired fear associations is critical in therapies for anxiety disorders. We tested whether findings with respect to the N-methyl-D-aspartate (NMDA) and cannabinoid receptor (CB) systems in animals carry over to healthy human subjects. To that end, we administered selected doses of D-cycloserine (partial NMDA receptor agonist, 250 mg), delta-9-tetrahydrocannabinol (THC, CB1 receptor agonist, 10 mg), or placebo prior to the extinction session of a 3-day conditioning protocol. D-cycloserine did not affect within-session extinction, or the retention of extinction in healthy human participants, in contrast with patient data but in line with previous reports in healthy volunteers. During extinction training, Δ9-THC reduced conditioned skin conductance responses, but not fear-potentiated startle. This effect was not retained at the retention test 2 days later, suggesting it was dependent on acute effects of the drug. Our findings implicate that facilitation of the CB1 or NMDA system with the substances used in this study does not affect conditioned fear extinction lastingly in healthy humans. The apparent discrepancy between these findings and the results from (pre-) clinical trials is discussed in terms of room for improvement in these systems in healthy volunteers, and the lack of specificity of THC as a CB1 agonist. PMID:22351380

  6. Teens that fear screams: A comparison of fear conditioning, extinction, and reinstatement in adolescents and adults.

    Science.gov (United States)

    Den, Miriam Liora; Graham, Bronwyn M; Newall, Carol; Richardson, Rick

    2015-11-01

    This study investigated differences between adolescents and adults on fear conditioning, extinction, and reinstatement (i.e., the recovery of conditioned fear following re-exposure to the unconditioned stimulus [US] post-extinction). Participants underwent differential conditioning (i.e., the Screaming Lady) where one neutral face (CS+) was followed by the same face expressing fear and a loud scream (US) while another neutral face (CS-) remained neutral. Extinction involved non-reinforced presentations of both CSs, after which participants were reinstated (2xUSs) or not. On two self-report measures, both ages showed conditioning, good extinction learning and retention, and reinstatement-induced relapse. However, only adolescents showed conditioning, extinction, and reinstatement on the eye tracking measure; relapse on this measure could not be assessed in adults given they did not show initial conditioning. Lastly, higher levels of depression predicted stronger conditioning and weaker extinction in adolescents only. These findings are discussed in terms of their implications for adolescent anxiety disorders. © 2015 Wiley Periodicals, Inc.

  7. Beam instability Workshop - plenary sessions

    International Nuclear Information System (INIS)

    2001-01-01

    The purpose of this workshop was to provide a review of the mechanisms of limiting beam instabilities, their cures, including feedback, and beam measurement for synchrotron radiation light sources. 12 plenary sessions took place whose titles are: 1) challenging brilliance and lifetime issues with increasing currents; 2) limiting instabilities in multibunch; 3) experience from high currents in B factories; 4) longitudinal dynamics in high intensity/bunch; 5) Transverse instabilities for high intensity/bunch; 6) working group introduction from ESRF experience; 7) impedance modelling: simulations, minimization; 8) report on the broadband impedance measurements and modelling workshop; 9) feedback systems for synchrotron light sources; 10) beam instabilities diagnostics; 11) harmonic cavities: the pros and cons; and 12) experimental study of fast beam-ion instabilities at PLS. This document gathers the 12 articles that were presented during these sessions

  8. National Sessions of Radiation Protection

    International Nuclear Information System (INIS)

    Sociedad Argentina de Radioproteccion

    2012-01-01

    The Radioprotection Argentine Society (SAR) was organized the National Sessions on Radiation Protection 2012 in order to continue the exchange in the radiation protection community in the country, on work areas that present a challenge to the profession. The new recommendations of the ICRP and the IAEA Safety Standards (2011), among others, includes several topics that are necessary to develop. The SAR wants to encourage different organizations from Argentina, to submit projects that are developing in order to strengthen radiation protection.

  9. Vicarious extinction learning during reconsolidation neutralizes fear memory.

    Science.gov (United States)

    Golkar, Armita; Tjaden, Cathelijn; Kindt, Merel

    2017-05-01

    Previous studies have suggested that fear memories can be updated when recalled, a process referred to as reconsolidation. Given the beneficial effects of model-based safety learning (i.e. vicarious extinction) in preventing the recovery of short-term fear memory, we examined whether consolidated long-term fear memories could be updated with safety learning accomplished through vicarious extinction learning initiated within the reconsolidation time-window. We assessed this in a final sample of 19 participants that underwent a three-day within-subject fear-conditioning design, using fear-potentiated startle as our primary index of fear learning. On day 1, two fear-relevant stimuli (reinforced CSs) were paired with shock (US) and a third stimulus served as a control (CS). On day 2, one of the two previously reinforced stimuli (the reminded CS) was presented once in order to reactivate the fear memory 10 min before vicarious extinction training was initiated for all CSs. The recovery of the fear memory was tested 24 h later. Vicarious extinction training conducted within the reconsolidation time window specifically prevented the recovery of the reactivated fear memory (p = 0.03), while leaving fear-potentiated startle responses to the non-reactivated cue intact (p = 0.62). These findings are relevant to both basic and clinical research, suggesting that a safe, non-invasive model-based exposure technique has the potential to enhance the efficiency and durability of anxiolytic therapies. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Light extinction in the atmosphere

    International Nuclear Information System (INIS)

    Laulainen, N.

    1992-06-01

    Atmospheric aerosol particles originating from natural sources, such as volcanos and sulfur-bearing gas emissions from the oceans, and from human sources, such as sulfur emissions from fossil fuel combustion and biomass burning, strongly affect visual air quality and are suspected to significantly affect radiative climate forcing of the planet. During the daytime, aerosols obscure scenic vistas, while at night they diminish our ability to observe stellar objects. Scattering of light is the main means by which aerosols attenuate and redistribute light in the atmosphere and by which aerosols can alter and reduce visibility and potentially modify the energy balance of the planet. Trends and seasonal variability of atmospheric aerosol loading, such as column-integrated light extinction or optical depth, and how they may affect potential climate change have been difficult to quantify because there have been few observations made of important aerosol optical parameters, such as optical depth, over the globe and over time and often these are of uneven quality. To address questions related to possible climate change, there is a pressing need to acquire more high-quality aerosol optical depth data. Extensive deployment of improved solar radiometers over the next few years will provide higher-quality extinction data over a wider variety of locations worldwide. An often overlooked source of turbidity data, however, is available from astronomical observations, particularly stellar photoelectric photometry observations. With the exception of the Project ASTRA articles published almost 20 years ago, few of these data ever appear in the published literature. This paper will review the current status of atmospheric extinction observations, as highlighted by the ASTRA work and augmented by more recent solar radiometry measurements

  11. The astronomical pulse of global extinction events.

    Science.gov (United States)

    Lewis, David F V; Dorne, Jean-Lou C M

    2006-06-23

    The linkage between astronomical cycles and the periodicity of mass extinctions is reviewed and discussed. In particular, the apparent 26 million year cycle of global extinctions may be related to the motion of the solar system around the galaxy, especially perpendicular to the galactic plane. The potential relevance of Milankovitch cycles is also explored in the light of current evidence for the possible causes of extinction events over a geological timescale.

  12. The Astronomical Pulse of Global Extinction Events

    Directory of Open Access Journals (Sweden)

    David F.V. Lewis

    2006-01-01

    Full Text Available The linkage between astronomical cycles and the periodicity of mass extinctions is reviewed and discussed. In particular, the apparent 26 million year cycle of global extinctions may be related to the motion of the solar system around the galaxy, especially perpendicular to the galactic plane. The potential relevance of Milankovitch cycles is also explored in the light of current evidence for the possible causes of extinction events over a geological timescale.

  13. Methylphenidate enhances extinction of contextual fear

    OpenAIRE

    Abraham, Antony D.; Cunningham, Christopher L.; Lattal, K. Matthew

    2012-01-01

    Methylphenidate (MPH, Ritalin) is a norepinephrine and dopamine transporter blocker that is widely used in humans for treatment of attention deficit disorder and narcolepsy. Although there is some evidence that targeted microinjections of MPH may enhance fear acquisition, little is known about the effect of MPH on fear extinction. Here, we show that MPH, administered before or immediately following extinction of contextual fear, will enhance extinction retention in C57BL/6 mice. Animals that ...

  14. Are Humans too Numerous to Become Extinct?

    OpenAIRE

    Cairns, John

    2009-01-01

    Some claim that humans are too numerous to become extinct. However, passenger pigeon, once the most numerous birds on the planet, are now extinct. For years, humankind has been damaging its habitat, discharging toxic chemicals into the environment, and having harmful effects on agricultural productivity due to climate change. Humankind s extinction depends on the continuation of various human activities including economic growth, addiction to fossil fuel, over consumption, overpopulation, oc...

  15. Erasing fear memories with extinction training

    OpenAIRE

    Quirk, Gregory J.; Paré, Denis; Richardson, Rick; Herry, Cyril; Monfils, Marie H.; Schiller, Daniela; Vicentic, Aleksandra

    2010-01-01

    Decades of behavioral studies have confirmed that extinction does not erase classically-conditioned fear memories. For this reason, research efforts have focused on the mechanisms underlying the development of extinction-induced inhibition within fear circuits. However, recent studies in rodents have uncovered mechanisms that stabilize and destabilize fear memories, opening the possibility that extinction might be used to erase fear memories. This symposium focuses on several of these new dev...

  16. Long-term maintenance of immediate or delayed extinction is determined by the extinction-test interval

    OpenAIRE

    Johnson, Justin S.; Escobar, Martha; Kimble, Whitney L.

    2010-01-01

    Short acquisition-extinction intervals (immediate extinction) can lead to either more or less spontaneous recovery than long acquisition-extinction intervals (delayed extinction). Using rat subjects, we observed less spontaneous recovery following immediate than delayed extinction (Experiment 1). However, this was the case only if a relatively long extinction-test interval was used; a relatively short extinction-test interval yielded the opposite result (Experiment 2). Previous data appear co...

  17. The Near-IR Extinction Law

    Science.gov (United States)

    Stead, Joseph J.; Hoare, Melvin G.

    2010-11-01

    We show that the power-law slope of the near-IR extinction law is significantly steeper than previously thought. Simulated colour-colour diagrams including a stellar population synthesis, realistic extinction distribution along the line-of-sight and synthesis through the filter profiles are compared to data from the UKIDSS Galactic Plane Survey. The slope of extinction with wavelength is found to be 2.14 ± 0.05 for total visual extinctions up to about 25 magnitudes and for a number of locations.

  18. Intergalactic extinction and the deceleration parameter

    International Nuclear Information System (INIS)

    Meinel, R.

    1981-01-01

    The deceleration parameter q 0 is calculated from the relation between apparent magnitudes m of the brightest galaxies in clusters and their redshifts z considering an intergalactic extinction. The calculation is valid for a Friedman universe, homogeneously filled with dust grains, assuming the extinction to be 0.5 mag at z = 1 and aΛ -1 -law of extinction (according to Oleak and Schmidt 1976). Using the m,z-values of Kristian, Sandage, and Westphal (1978) a formal value of q 0 approximately 2.1 is obtained instead of q 0 approximately 1.6 without consideration of intergalactic extinction. (author)

  19. Interstellar extinction in the Large Magellanic Cloud

    International Nuclear Information System (INIS)

    Nandy, K.; Morgan, D.H.; Willis, A.J.; Wilson, R.; Gondhalekar, P.M.; Houziaux, L.

    1980-01-01

    Recent UV observations together with complementary visible data of several reddened and comparison stars of similar spectral types in the Large Magellanic Cloud have been used to study the interstellar extinction in that galaxy. Most of the reddened stars studied here are located within 2 0 of 30 Doradus and show remarkably high extinction in the far UV, suggesting a large abundance of small particles. From the optical wavelength to 2,600 A the normalised extinction curves of the LMC stars are similar to the mean galactic extinction law. (author)

  20. Mass extinctions vs. uniformitarianism in biological evolution

    Energy Technology Data Exchange (ETDEWEB)

    Bak, P.; Paczuski, M.

    1995-12-31

    It is usually believed that Darwin`s theory leads to a smooth gradual evolution, so that mass extinctions must be caused by external shocks. However, it has recently been argued that mass extinctions arise from the intrinsic dynamics of Darwinian evolution. Species become extinct when swept by intermittent avalanches propagating through the global ecology. These ideas are made concrete through studies of simple mathematical models of co-evolving species. The models exhibit self-organized criticality and describe some general features of the extinction pattern in the fossil record.

  1. Timing of extinction relative to acquisition: A parametric analysis of fear extinction in humans

    NARCIS (Netherlands)

    Norrholm, S.D.; Vervliet, B.; Jovanovic, T.; Boshoven, W.; Myers, K.M.; Davis, M.; Rothbaum, B.O.; Duncan, E.J.

    2008-01-01

    Fear extinction is a reduction in conditioned fear following repeated exposure to the feared cue in the absence of any aversive event. Extinguished fear often reappears after extinction through spontaneous recovery. Animal studies suggest that spontaneous recovery can be abolished if extinction

  2. Constraints on Enhanced Extinction Resulting from Extinction Treatment in the Presence of an Added Excitor

    Science.gov (United States)

    Urcelay, Gonzalo P.; Lipatova, Olga; Miller, Ralph R.

    2009-01-01

    Three Pavlovian fear conditioning experiments with rats as subjects explored the effect of extinction in the presence of a concurrent excitor. Our aim was to explore this particular treatment, documented in previous studies to deepen extinction, with novel control groups to shed light on the processes involved in extinction. Relative to subjects…

  3. CIME Session on Pluripotential Theory

    CERN Document Server

    Patrizio, Giorgio; Berteloot, Francois; Demailly, Jean Pierre

    2013-01-01

    Pluripotential theory is a very powerful tool in geometry, complex analysis and dynamics. This volume brings together the lectures held at the 2011 CIME session on "pluripotential theory" in Cetraro, Italy. This CIME course focused on complex Monge-Ampére equations, applications of pluripotential theory to Kahler geometry and algebraic geometry and to holomorphic dynamics. The contributions provide an extensive description of the theory and its very recent developments, starting from basic introductory materials and concluding with open questions in current research.

  4. Working session 3: Tubing integrity

    International Nuclear Information System (INIS)

    Cueto-Felgueroso, C.; Strosnider, J.

    1997-01-01

    Twenty-three individuals representing nine countries (Belgium, Canada, the Czech Republic, France, Japan, the Slovak Republic, Spain, the UK, and the US) participated in the session on tube integrity. These individuals represented utilities, vendors, consultants and regulatory authorities. The major subjects discussed by the group included overall objectives of managing steam generator tube degradation, necessary elements of a steam generator degradation management program, the concept of degradation specific management, structural integrity evaluations, leakage evaluations, and specific degradation mechanisms. The group's discussions on these subjects, including conclusions and recommendations, are summarized in this article

  5. The role of response force on the persistence and structure of behavior during extinction.

    Science.gov (United States)

    Pinkston, Jonathan W; Foss, Erica K

    2018-01-01

    Behavior Momentum Theory has emerged as a prominent account of resistance to change in both basic and applied research. Although laboratory studies often define precise, repeatable responses, application research often deals with response classes that may vary widely along a number of dimensions. In general, Behavior Momentum Theory has not addressed how response dimensions impact resistance to change, providing an opportunity to expand the model in new directions. Four rats pressed a force transducer under a multiple variable interval (VI) 60-s VI 60-s schedule of reinforcement. In one component, responses satisfied the schedule only if the response force fell within a "low" force band requirement; responses in the other schedule were required to satisfy a "high" force band. Once responding stabilized, extinction was programmed for three sessions. Then, the procedures were replicated. The results showed that response force came under discriminative control, but force requirements had no impact on resistance to extinction. In a follow-up condition, the schedule was changed to a multiple VI 30-s VI 120-s schedule and the low-force band operated in both components. The results showed that behavior maintained by the VI 30-s schedule was generally more resistant to extinction. A secondary analysis showed that force distributions created under baseline maintained during extinction. Overall, the results suggest that differential response force requirements prevailing in steady state do not affect the course of extinction. © 2018 Society for the Experimental Analysis of Behavior.

  6. Long-Term Maintenance of Immediate or Delayed Extinction Is Determined by the Extinction-Test Interval

    Science.gov (United States)

    Johnson, Justin S.; Escobar, Martha; Kimble, Whitney L.

    2010-01-01

    Short acquisition-extinction intervals (immediate extinction) can lead to either more or less spontaneous recovery than long acquisition-extinction intervals (delayed extinction). Using rat subjects, we observed less spontaneous recovery following immediate than delayed extinction (Experiment 1). However, this was the case only if a relatively…

  7. Working session 1: Tubing degradation

    International Nuclear Information System (INIS)

    Kharshafdjian, G.; Turluer, G.

    1997-01-01

    A general introductory overview of the purpose of the group and the general subject area of SG tubing degradation was given by the facilitator. The purpose of the session was described as to open-quotes develop conclusions and proposals on regulatory and technical needs required to deal with the issues of SG tubing degradation.close quotes Types, locations and characteristics of tubing degradation in steam generators were briefly reviewed. The well-known synergistic effects of materials, environment, and stress and strain/strain rate, subsequently referred to by the acronym open-quotes MESSclose quotes by some of the group members, were noted. The element of time (i.e., evolution of these variables with time) was emphasized. It was also suggested that the group might want to consider the related topics of inspection capabilities, operational variables, degradation remedies, and validity of test data, and some background information in these areas was provided. The presentation given by Peter Millet during the Plenary Session was reviewed; Specifically, the chemical aspects and the degradation from the secondary side of the steam generator were noted. The main issues discussed during the October 1995 EPRI meeting on secondary side corrosion were reported, and a listing of the potential SG tube degradations was provided and discussed

  8. The Effects of Functional Knee Brace on Postural Control in Patients Who Underwent Anterior Cruciate Ligament Reconstruction

    Directory of Open Access Journals (Sweden)

    Salehi

    2016-09-01

    Full Text Available Background The current study aimed to evaluate the postural control in patients underwent anterior cruciate ligament reconstruction pre and post wearing functional knee brace. Methods Eighteen athletes undergone unilateral anterior cruciate ligament reconstruction included in the study. They had unilateral anterior cruciate ligament reconstruction at least six months before session test. Postural control was assessed pre and post wearing custom-fit functional knee brace using a posturographic platform prokin 254. The balance tests included: 1 standing on prokin platform with eyes open/closed on anterior cruciate ligament reconstruction limb, 2 standing on prokin platform with eyes open/closed on both limbs. The standard deviation (SD of body sway along the anteroposterior (AP and mediolateral (ML axis, mean velocity of center of pressure (COP along AP/ ML axis and the area ellipse (measured in 2 mm were calculated. Results Results of the paired T-test revealed a significant effect on selected postural control variables for the brace conditions especially in low challengeable conditions (double leg, eyes open test situations (P < 0.05. But in high challengeable conditions this effect was not significant. Conclusions Functional knee brace improved postural control in the simple balancing task in the subjects with anterior cruciate ligament reconstruction. But this improvement in more difficult balancing task was limited.

  9. Evaluating herbivore extinction probabilities in Addo Elephant ...

    African Journals Online (AJOL)

    Abstract. Population extinction evaluations, based on the model developed by Dennis et al. (1991) that did not take density dependence into account and that were based on census data, suggest that many of the herbivore species in Addo Elephant National Park (AENP) are vulnerable to local extinction. As a result of low ...

  10. Extinction-Induced Variability in Human Behavior

    Science.gov (United States)

    Kinloch, Jennifer M.; Foster, T. Mary; McEwan, James S. A.

    2009-01-01

    Participants earned points by pressing a computer space bar (Experiment 1) or forming rectangles on the screen with the mouse (Experiment 2) under differential-reinforcement-of-low-rate schedules, followed by extinction. Variability in interresponse time (the contingent dimension) increased during extinction, as for Morgan and Lee (1996);…

  11. Interstellar extinction in the Large Magellanic Cloud

    International Nuclear Information System (INIS)

    Nandy, K.; Morgan, D.H.; Willis, A.J.; Wilson, R.; Gondhalekar, P.M.

    1981-01-01

    A systematic investigation of interstellar extinction in the ultraviolet as a function of position in the Large Magellanic Cloud has been made from an enlarged sample of reddened and comparison stars distributed throughout the cloud. Except for one star SK-69-108, the most reddened star of our sample, the shape of the extinction curves for the LMC stars do not show significant variations. All curves show an increase in extinction towards 2200 A, but some have maxima near 2200 A, some near 1900 A. It has been shown that the feature of the extinction curve near 1900 A is caused by the mismatch of the stellar F III 1920 A feature. The strength of this 1920 A feature as a function of luminosity and spectral type has been determined. The extinction curves have been corrected for the mismatch of the 1920 feature and a single mean extinction curve for the LMC normalized to Asub(V) = 0 and Esub(B-V) = 1 is presented. For the same value of Esub(B-V) the LMC stars show the 2200 A feature weaker by a factor 2 as compared with the galactic stars. Higher extinction shortward of 2000 A in the LMC extinction curves than that in our Galaxy, as reported in earlier papers, is confirmed. (author)

  12. Defining the period of moa extinction

    International Nuclear Information System (INIS)

    Anderson, A.

    2000-01-01

    Few aspects of New Zealand's prehistory have engaged scientific and public attention so consistently as two interlinked questions of moa extinction; when did moas become extinct and why? Answers offered over the last 160 years have run the gamut from chronological antiquity by evolutionary senescence, to within the 19th century Maori and European disturbance. (author)

  13. Current extinction rates of reptiles and amphibians.

    Science.gov (United States)

    Alroy, John

    2015-10-20

    There is broad concern that a mass extinction of amphibians and reptiles is now underway. Here I apply an extremely conservative Bayesian method to estimate the number of recent amphibian and squamate extinctions in nine important tropical and subtropical regions. The data stem from a combination of museum collection databases and published site surveys. The method computes an extinction probability for each species by considering its sighting frequency and last sighting date. It infers hardly any extinction when collection dates are randomized and it provides underestimates when artificial extinction events are imposed. The method also appears to be insensitive to trends in sampling; therefore, the counts it provides are absolute minimums. Extinctions or severe population crashes have accumulated steadily since the 1970s and 1980s, and at least 3.1% of frog species have already disappeared. Based on these data and this conservative method, the best estimate of the global grand total is roughly 200 extinctions. Consistent with previous results, frog losses are heavy in Latin America, which has been greatly affected by the pathogenic chytrid fungus Batrachochytrium dendrobatidis. Extinction rates are now four orders-of-magnitude higher than background, and at least another 6.9% of all frog species may be lost within the next century, even if there is no acceleration in the growth of environmental threats.

  14. Climate predictors of late quaternary extinctions

    DEFF Research Database (Denmark)

    Nogués-Bravo, David; Ohlemüller, Ralf; Batra, Persaram

    2010-01-01

    Between 50,000 and 3,000 years before present (BP) 65% of mammal genera weighing over 44 kg went extinct, together with a lower proportion of small mammals. Why species went extinct in such large numbers is hotly debated. One of the arguments proposes that climate changes underlie Late Quaternary...

  15. Immediate extinction promotes the return of fear.

    Science.gov (United States)

    Merz, Christian J; Hamacher-Dang, Tanja C; Wolf, Oliver T

    2016-05-01

    Accumulating evidence indicates that immediate extinction is less effective than delayed extinction in attenuating the return of fear. This line of fear conditioning research impacts the proposed onset of psychological interventions after threatening situations. In the present study, forty healthy men were investigated in a differential fear conditioning paradigm with fear acquisition in context A, extinction in context B, followed by retrieval testing in both contexts 24h later to test fear renewal. Differently coloured lights served as conditioned stimuli (CS): two CS (CS+) were paired with an electrical stimulation that served as unconditioned stimulus, the third CS was never paired (CS-). Extinction took place immediately after fear acquisition or 24h later. One CS+ was extinguished whereas the second CS+ remained unextinguished to control for different time intervals between fear acquisition and retrieval testing. Immediate extinction led to larger skin conductance responses during fear retrieval to both the extinguished and unextinguished CS relative to the CS-, indicating a stronger return of fear compared to delayed extinction. Taken together, immediate extinction is less potent than delayed extinction and is associated with a stronger renewal effect. Thus, the time-point of psychological interventions relative to the offset of threatening situations needs to be carefully considered to prevent relapses. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Contextual change after fear acquisition affects conditioned responding and the time course of extinction learning – Implications for renewal research

    Directory of Open Access Journals (Sweden)

    Rachel eSjouwerman

    2015-12-01

    Full Text Available Context plays a central role in retrieving (fear memories. Accordingly, context manipulations are inherent to most return of fear (ROF paradigms (in particular renewal, involving contextual changes after fear extinction. Context changes are, however, also often embedded during earlier stages of ROF experiments such as context changes between fear acquisition and extinction (e.g. in ABC and ABA renewal. Previous studies using these paradigms have however focused exclusively on the context switch after extinction (i.e. renewal. Thus, the possibility of a general effect of a context switch on conditioned responding that may not be conditional to preceding extinction learning remains unstudied.Hence, the current study investigated the impact of a context switch between fear acquisition and extinction on immediate conditioned responding and on the time-course of extinction learning by using a multimodal approach. A group that underwent contextual change after fear conditioning (AB; n = 36 was compared with a group without a contextual change from acquisition to extinction (AA; n = 149, while measuring autonomic (skin conductance and fear potentiated startle measures and subjective fear ratings. Contextual change between fear acquisition and extinction had a pronounced effect on both immediate conditioned responding and on the time course of extinction learning in skin conductance responses and subjective fear ratings. This may have important implications for the mechanisms underlying and the interpretation of the renewal effect (i.e. contextual switch after extinction. Consequently, future studies should incorporate designs and statistical tests that disentangle general effects of contextual change from genuine ROF effects.

  17. Towards a better preclinical model of PTSD: characterizing animals with weak extinction, maladaptive stress responses and low plasma corticosterone.

    Science.gov (United States)

    Reznikov, Roman; Diwan, Mustansir; Nobrega, José N; Hamani, Clement

    2015-02-01

    Most of the available preclinical models of PTSD have focused on isolated behavioural aspects and have not considered individual variations in response to stress. We employed behavioural criteria to identify and characterize a subpopulation of rats that present several features analogous to PTSD-like states after exposure to classical fear conditioning. Outbred Sprague-Dawley rats were segregated into weak- and strong-extinction groups on the basis of behavioural scores during extinction of conditioned fear responses. Animals were subsequently tested for anxiety-like behaviour in the open-field test (OFT), novelty suppressed feeding (NSF) and elevated plus maze (EPM). Baseline plasma corticosterone was measured prior to any behavioural manipulation. In a second experiment, rats underwent OFT, NSF and EPM prior to being subjected to fear conditioning to ascertain whether or not pre-stress levels of anxiety-like behaviours could predict extinction scores. We found that 25% of rats exhibit low extinction rates of conditioned fear, a feature that was associated with increased anxiety-like behaviour across multiple tests in comparison to rats showing strong extinction. In addition, weak-extinction animals showed low levels of corticosterone prior to fear conditioning, a variable that seemed to predict extinction recall scores. In a separate experiment, anxiety measures taken prior to fear conditioning were not predictive of a weak-extinction phenotype, suggesting that weak-extinction animals do not show detectable traits of anxiety in the absence of a stressful experience. These findings suggest that extinction impairment may be used to identify stress-vulnerable rats, thus providing a useful model for elucidating mechanisms and investigating potential treatments for PTSD. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Enhancing Divergent Search through Extinction Events

    DEFF Research Database (Denmark)

    Lehman, Joel; Miikkulainen, Risto

    2015-01-01

    A challenge in evolutionary computation is to create representations as evolvable as those in natural evolution. This paper hypothesizes that extinction events, i.e. mass extinctions, can significantly increase evolvability, but only when combined with a divergent search algorithm, i.e. a search...... driven towards diversity (instead of optimality). Extinctions amplify diversity-generation by creating unpredictable evolutionary bottlenecks. Persisting through multiple such bottlenecks is more likely for lineages that diversify across many niches, resulting in indirect selection pressure...... for the capacity to evolve. This hypothesis is tested through experiments in two evolutionary robotics domains. The results show that combining extinction events with divergent search increases evolvability, while combining them with convergent search offers no similar benefit. The conclusion is that extinction...

  19. Mass extinction in poorly known taxa.

    Science.gov (United States)

    Régnier, Claire; Achaz, Guillaume; Lambert, Amaury; Cowie, Robert H; Bouchet, Philippe; Fontaine, Benoît

    2015-06-23

    Since the 1980s, many have suggested we are in the midst of a massive extinction crisis, yet only 799 (0.04%) of the 1.9 million known recent species are recorded as extinct, questioning the reality of the crisis. This low figure is due to the fact that the status of very few invertebrates, which represent the bulk of biodiversity, have been evaluated. Here we show, based on extrapolation from a random sample of land snail species via two independent approaches, that we may already have lost 7% (130,000 extinctions) of the species on Earth. However, this loss is masked by the emphasis on terrestrial vertebrates, the target of most conservation actions. Projections of species extinction rates are controversial because invertebrates are essentially excluded from these scenarios. Invertebrates can and must be assessed if we are to obtain a more realistic picture of the sixth extinction crisis.

  20. Extinctions in ancient and modern seas.

    Science.gov (United States)

    Harnik, Paul G; Lotze, Heike K; Anderson, Sean C; Finkel, Zoe V; Finnegan, Seth; Lindberg, David R; Liow, Lee Hsiang; Lockwood, Rowan; McClain, Craig R; McGuire, Jenny L; O'Dea, Aaron; Pandolfi, John M; Simpson, Carl; Tittensor, Derek P

    2012-11-01

    In the coming century, life in the ocean will be confronted with a suite of environmental conditions that have no analog in human history. Thus, there is an urgent need to determine which marine species will adapt and which will go extinct. Here, we review the growing literature on marine extinctions and extinction risk in the fossil, historical, and modern records to compare the patterns, drivers, and biological correlates of marine extinctions at different times in the past. Characterized by markedly different environmental states, some past periods share common features with predicted future scenarios. We highlight how the different records can be integrated to better understand and predict the impact of current and projected future environmental changes on extinction risk in the ocean. Copyright © 2012 Elsevier Ltd. All rights reserved.

  1. A phantom extinction? New insights into extinction dynamics of the Don-hare Lepus tanaiticus.

    Science.gov (United States)

    Prost, S; Knapp, M; Flemmig, J; Hufthammer, A K; Kosintsev, P; Stiller, M; Hofreiter, M

    2010-09-01

    The Pleistocene to Holocene transition was accompanied by a worldwide extinction event affecting numerous mammalian species. Several species such as the woolly mammoth and the giant deer survived this extinction wave, only to go extinct a few thousand years later during the Holocene. Another example for such a Holocene extinction is the Don-hare, Lepus tanaiticus, which inhabited the Russian plains during the late glacial. After being slowly replaced by the extant mountain hare (Lepus timidus), it eventually went extinct during the middle Holocene. Here, we report the phylogenetic relationship of L. tanaiticus and L. timidus based on a 339-basepair (bp) fragment of the mitochondrial D-loop. Phylogenetic tree- and network reconstructions do not support L. tanaiticus and L. timidus being different species. Rather, we suggest that the two taxa represent different morphotypes of a single species and the extinction of 'L. tanaiticus' represents the disappearance of a local morphotype rather than the extinction of a species.

  2. Enhancement of Extinction Learning Attenuates Ethanol-Seeking Behavior and Alters Plasticity in the Prefrontal Cortex

    Science.gov (United States)

    Trantham-Davidson, Heather; Kassab, Amanda S.; Glen, William B.; Olive, M. Foster; Chandler, L. Judson

    2014-01-01

    Addiction is a chronic relapsing disorder in which relapse is often initiated by exposure to drug-related cues. The present study examined the effects of mGluR5 activation on extinction of ethanol-cue-maintained responding, relapse-like behavior, and neuronal plasticity. Rats were trained to self-administer ethanol and then exposed to extinction training during which they were administered either vehicle or the mGluR5 positive allosteric modulator 3-cyano-N-(1,3-diphenyl-1H-pyrazol-5-yl) or CDPPB. CDPPB treatment reduced active lever responding during extinction, decreased the total number of extinction sessions required to meet criteria, and attenuated cue-induced reinstatement of ethanol seeking. CDPPB facilitation of extinction was blocked by the local infusion of the mGluR5 antagonist 3-((2-methyl-4-thiazolyl)ethynyl) pyridine into the infralimbic (IfL) cortex, but had no effect when infused into the prelimbic (PrL) cortex. Analysis of dendritic spines revealed alterations in structural plasticity, whereas electrophysiological recordings demonstrated differential alterations in glutamatergic neurotransmission in the PrL and IfL cortex. Extinction was associated with increased amplitude of evoked synaptic PrL and IfL NMDA currents but reduced amplitude of PrL AMPA currents. Treatment with CDPPB prevented the extinction-induced enhancement of NMDA currents in PrL without affecting NMDA currents in the IfL. Whereas CDPPB treatment did not alter the amplitude of PrL or IfL AMPA currents, it did promote the expression of IfL calcium-permeable GluR2-lacking receptors in both abstinence- and extinction-trained rats, but had no effect in ethanol-naive rats. These results confirm changes in the PrL and IfL cortex in glutamatergic neurotransmission during extinction learning and demonstrate that manipulation of mGluR5 facilitates extinction of ethanol cues in association with neuronal plasticity. PMID:24872560

  3. Enhancement of extinction learning attenuates ethanol-seeking behavior and alters plasticity in the prefrontal cortex.

    Science.gov (United States)

    Gass, Justin T; Trantham-Davidson, Heather; Kassab, Amanda S; Glen, William B; Olive, M Foster; Chandler, L Judson

    2014-05-28

    Addiction is a chronic relapsing disorder in which relapse is often initiated by exposure to drug-related cues. The present study examined the effects of mGluR5 activation on extinction of ethanol-cue-maintained responding, relapse-like behavior, and neuronal plasticity. Rats were trained to self-administer ethanol and then exposed to extinction training during which they were administered either vehicle or the mGluR5 positive allosteric modulator 3-cyano-N-(1,3-diphenyl-1H-pyrazol-5-yl) or CDPPB. CDPPB treatment reduced active lever responding during extinction, decreased the total number of extinction sessions required to meet criteria, and attenuated cue-induced reinstatement of ethanol seeking. CDPPB facilitation of extinction was blocked by the local infusion of the mGluR5 antagonist 3-((2-methyl-4-thiazolyl)ethynyl) pyridine into the infralimbic (IfL) cortex, but had no effect when infused into the prelimbic (PrL) cortex. Analysis of dendritic spines revealed alterations in structural plasticity, whereas electrophysiological recordings demonstrated differential alterations in glutamatergic neurotransmission in the PrL and IfL cortex. Extinction was associated with increased amplitude of evoked synaptic PrL and IfL NMDA currents but reduced amplitude of PrL AMPA currents. Treatment with CDPPB prevented the extinction-induced enhancement of NMDA currents in PrL without affecting NMDA currents in the IfL. Whereas CDPPB treatment did not alter the amplitude of PrL or IfL AMPA currents, it did promote the expression of IfL calcium-permeable GluR2-lacking receptors in both abstinence- and extinction-trained rats, but had no effect in ethanol-naive rats. These results confirm changes in the PrL and IfL cortex in glutamatergic neurotransmission during extinction learning and demonstrate that manipulation of mGluR5 facilitates extinction of ethanol cues in association with neuronal plasticity. Copyright © 2014 the authors 0270-6474/14/347562-13$15.00/0.

  4. Trophic redundancy reduces vulnerability to extinction cascades.

    Science.gov (United States)

    Sanders, Dirk; Thébault, Elisa; Kehoe, Rachel; Frank van Veen, F J

    2018-03-06

    Current species extinction rates are at unprecedentedly high levels. While human activities can be the direct cause of some extinctions, it is becoming increasingly clear that species extinctions themselves can be the cause of further extinctions, since species affect each other through the network of ecological interactions among them. There is concern that the simplification of ecosystems, due to the loss of species and ecological interactions, increases their vulnerability to such secondary extinctions. It is predicted that more complex food webs will be less vulnerable to secondary extinctions due to greater trophic redundancy that can buffer against the effects of species loss. Here, we demonstrate in a field experiment with replicated plant-insect communities, that the probability of secondary extinctions is indeed smaller in food webs that include trophic redundancy. Harvesting one species of parasitoid wasp led to secondary extinctions of other, indirectly linked, species at the same trophic level. This effect was markedly stronger in simple communities than for the same species within a more complex food web. We show that this is due to functional redundancy in the more complex food webs and confirm this mechanism with a food web simulation model by highlighting the importance of the presence and strength of trophic links providing redundancy to those links that were lost. Our results demonstrate that biodiversity loss, leading to a reduction in redundant interactions, can increase the vulnerability of ecosystems to secondary extinctions, which, when they occur, can then lead to further simplification and run-away extinction cascades. Copyright © 2018 the Author(s). Published by PNAS.

  5. Predicting extinction debt from community patterns.

    Science.gov (United States)

    Kitzes, Justin; Harte, John

    2015-08-01

    A significant challenge in both measuring and predicting species extinction rates at global and local scales is the possibility of extinction debt, time-delayed extinctions that occur gradually following an initial impact. Here we examine how relative abundance distributions and spatial aggregation combine to influence the likely magnitude of future extinction debt following habitat loss or climate-driven range contraction. Our analysis is based on several fundamental premises regarding abundance distributions, most importantly that species abundances immediately following habitat loss are a sample from an initial relative abundance distribution and that the long-term, steady-state form of the species abundance distribution is a property of the biology of a community and not of area. Under these two hypotheses, the results show that communities following canonical lognormal and broken-stick abundance distributions are prone to exhibit extinction debt, especially when species exhibit low spatial aggregation. Conversely, communities following a logseries distribution with a constant Fisher's α parameter never demonstrate extinction debt and often show an "immigration credit," in which species richness rises in the long term following an initial decrease. An illustration of these findings in 25 biodiversity hotspots suggests a negligible immediate extinction rate for bird communities and eventual extinction debts of 30-50% of initial species richness, whereas plant communities are predicted to immediately lose 5-15% of species without subsequent extinction debt. These results shed light on the basic determinants of extinction debt and provide initial indications of the magnitude of likely debts in landscapes where few empirical data are available.

  6. Naloxone facilitates appetitive extinction and eliminates escape from frustration.

    Science.gov (United States)

    Norris, Jacob N; Pérez-Acosta, Andrés M; Ortega, Leonardo A; Papini, Mauricio R

    2009-11-01

    Two experiments tested the effects of opioid receptor blockage on behavior. In Experiment 1, rats reinforced for lever pressing with either sucrose or food pellets received treatment with saline, 2, and 10 mg/kg naloxone, i.p. (within-subject design). Naloxone 10 mg/kg increased response latency, but 2 mg/kg had no effect. When shifted to extinction (between-group design), naloxone (2 and 10 mg/kg) facilitated extinction relative to saline animals, after reinforcement with either sucrose or food pellets. In Experiment 2, after 10 sessions of access to 32% sucrose or an empty tube (between-group design), all rats were exposed to the empty tube while allowing them to jump over a barrier into a different compartment. Escape latencies were shorter for downshifted saline than for saline rats always given access to the empty tube. This escape-from-frustration effect was eliminated by naloxone (2 mg/kg, i.p.). Opioid blockage appears to reduce the value of alternative incentives.

  7. Working session 2: Tubing inspection

    International Nuclear Information System (INIS)

    Guerra, J.; Tapping, R.L.

    1997-01-01

    This session was attended by delegates from 10 countries, and four papers were presented. A wide range of issues was tabled for discussion. Realizing that there was limited time available for more detailed discussion, three topics were chosen for the more detailed discussion: circumferential cracking, performance demonstration (to focus on POD and sizing), and limits of methods. Two other subsessions were organized: one dealt with some challenges related to the robustness of current inspection methods, especially with respect to leaving cracked tubes in service, and the other with developing a chart of current NDE technology with recommendations for future development. These three areas are summarized in turn, along with conclusions and/or recommendations. During the discussions there were four presentations. There were two (Canada, Japan) on eddy current probe developments, both of which addressed multiarray probes that would detect a range of flaws, one (Spain) on circumferential crack detection, and one (JRC, Petten) on the recent PISC III results

  8. DWPF recycle minimization: Brainstorming session

    International Nuclear Information System (INIS)

    Jacobs, R.A.; Poirier, M.R.

    1993-01-01

    The recycle stream from the DWPF constitutes a major source of water addition to the High Level Waste evaporator system. As now designed, the entire flow of 3.5 to 6.5 gal/min (at sign 25% and 75% attainment, respectively), or 2 gal/min during idling, flow to the 2H evaporator system (Tank 43). Substantial improvement in the HLW water balance and tank volume management is expected if the DWPF recycle to the HLW evaporator system can be significantly reduced. A task team has been appointed to study alternatives for reducing the flow to the HLW evaporator system and make recommendations for implementation and/or further study and evaluation. The brainstorming session detailed in this report was designed to produce the first cut options for the task team to further evaluate

  9. Cinema Sessions in Primary Care

    Directory of Open Access Journals (Sweden)

    Francisco Ignacio MORETA-VELAYOS

    2016-04-01

    Full Text Available For a long time films have been used in teaching and at various levels of professional training  and more specifically in the medical area. In this case, through the description of a project developed in a Primary Care Health Center, we intend to justify the use of movies as a tool that could ease, the sometimes difficult task of continued education among Primary Care professionals. We propose different aspects of everyday practice in which cinema can be potentially useful, as well as the way to include it in the Plan of Continued Education of the Centre and its accreditation.Films and issues discussed in each session, and the project evaluation, are detailed.

  10. Celebrating the tenth conference session

    International Nuclear Information System (INIS)

    1966-01-01

    Full text: This number of the Bulletin appears during a month when the tenth regular session of the Agency's General Conference is being held. It is fitting that among the special arrangements made to give added significance to such an historical landmark should be an opening address by Herr Franz Jonas, Federal President of the host country, Austria. The Festsaal of the Kongresszentrum, in the Hofburg, has now been the centre for every annual session held in Austria, except the first. On that occasion, recorded in the photograph on the cover, the Konzerthaus was made available. A commemorative series of talks dealing with topics of particular interest in the international development of the peaceful uses of atomic energy, delivered by scientists of world distinction was another idea which will add much profound thought to the records of nuclear energy. Under the chairmanship of Professor L.C. Prado, with Dr. W.B. Lewis as Moderator, the subjects chosen by the participants were : The Impact of Atomic Energy in our Society - Sir John Cockcroft; Nuclear Power Systems and their Technical Potentialities - Prof. Alexandre Leipunski; The Commercial Future of Nuclear Power - Dr. William Webster; Nuclear Science in Life Sciences - Dr. A.R. Gopal-Ayengar; Fundamental Research in Atomic Energy Centres - Prof. Louis Neel. These speeches will be reproduced in full in the Agency's Atomic Energy Review. The pages of this issue of the Bulletin are intended to give indications of the stage which the Agency has now reached in some, but by no means all, of its activities in promoting the techniques of atomic energy for the benefit of mankind. (author)

  11. Effect of conditioned stimulus exposure during slow wave sleep on fear memory extinction in humans.

    Science.gov (United States)

    He, Jia; Sun, Hong-Qiang; Li, Su-Xia; Zhang, Wei-Hua; Shi, Jie; Ai, Si-Zhi; Li, Yun; Li, Xiao-Jun; Tang, Xiang-Dong; Lu, Lin

    2015-03-01

    Repeated exposure to a neutral conditioned stimulus (CS) in the absence of a noxious unconditioned stimulus (US) elicits fear memory extinction. The aim of the current study was to investigate the effects of mild tone exposure (CS) during slow wave sleep (SWS) on fear memory extinction in humans. The healthy volunteers underwent an auditory fear conditioning paradigm on the experimental night, during which tones served as the CS, and a mild shock served as the US. They were then randomly assigned to four groups. Three groups were exposed to the CS for 3 or 10 min or an irrelevant tone (control stimulus, CtrS) for 10 min during SWS. The fourth group served as controls and was not subjected to any interventions. All of the subjects completed a memory test 4 h after SWS-rich stage to evaluate the effect on fear extinction. Moreover, we conducted similar experiments using an independent group of subjects during the daytime to test whether the memory extinction effect was specific to the sleep condition. Ninety-six healthy volunteers (44 males) aged 18-28 y. Participants exhibited undisturbed sleep during 2 consecutive nights, as assessed by sleep variables (all P > 0.05) from polysomnographic recordings and power spectral analysis. Participants who were re-exposed to the 10 min CS either during SWS and wakefulness exhibited attenuated fear responses (wake-10 min CS, P memory extinction without altering sleep profiles. © 2015 Associated Professional Sleep Societies, LLC.

  12. Pavlovian Extinction and Recovery Effects in Aversive Pavlovian to Instrumental Transfer

    Directory of Open Access Journals (Sweden)

    Vincent D. Campese

    2017-09-01

    Full Text Available Three studies explored the sensitivity of aversive Pavlovian to instrumental transfer (PIT to Pavlovian extinction in rodents. Rats underwent Pavlovian conditioning prior to avoidance training. The PIT test then involved assessment of the effects of the Pavlovian conditioned stimulus (CS on the performance of the avoidance response (AR. Conducting extinction prior to avoidance training and transfer testing, allowed spontaneous recovery and shock reinstatement of extinguished motivation, whereas conducting extinction following avoidance training and just prior to PIT testing successfully reduced transfer effects. This was also the case in a design that compared responding to an extinguished CS against a non-extinguished CS rather than comparing extinguished and non-extinguished groups to one another. While extinction treatments in many appetitive PIT studies do not successfully reduce transfer, and can sometimes enhance the effect, the current findings show that an extinction treatment temporally close to transfer testing can reduce the motivational impact of the aversive Pavlovian CS on instrumental avoidance responding.

  13. Diazepam effects on aversive memory retrieval and extinction: Role of anxiety levels.

    Science.gov (United States)

    Leão, Anderson H F F; Cabral, Alícia; Izídio, Geison S; Ribeiro, Alessandra M; Silva, Regina H

    2016-02-01

    Benzodiazepines (BDZs) are anxiolytic drugs that impair memory acquisition. Previous studies using the plus-maze discriminative avoidance task (PMDAT, which assesses memory and anxiety concomitantly) indicated that the effects of BDZs on anxiety and acquisition are related to each other. The possible influence of the anxiolytic action of BDZs on their effects on memory retrieval and extinction are poorly understood. This is relevant considering the relationship between aversive memories and anxiety disorders. We designed a modified protocol of PMDAT that evaluates anxiety during retrieval and extinction of the task. Male Wistar rats were trained in the PMDAT (plus-maze with two open and two enclosed arms) using a standard or a modified protocol. In the standard protocol, the aversive stimuli were presented in one of the enclosed arms during training, and the animal had free access to the whole apparatus. In the modified protocol, the open arms were blocked with glass walls. Twenty-four hours after training, the animals subjected to each of the protocols were treated with saline or 2.0mg/kg of diazepam (DZP) 30min before the test. There was a third session in the maze (retest) 24h after the test. During the test, DZP impaired and improved retrieval in rats that had been trained in the standard and the modified protocol when compared to the respective saline-treated groups. In addition, treatment with DZP prior to the test induced anxiolysis, but only in the animals that were not pre-exposed to the open arms of the apparatus (modified protocol). In these animals, DZP impaired extinction, which was evaluated during retest session. The impairing effect of DZP on extinction seems to be related to its anxiolytic action during the test (extinction learning). Further, we suggest that aversive memory retrieval depends on both the treatment and the arousal elicited by exposure to the apparatus. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Estimating extinction using unsupervised machine learning

    Science.gov (United States)

    Meingast, Stefan; Lombardi, Marco; Alves, João

    2017-05-01

    Dust extinction is the most robust tracer of the gas distribution in the interstellar medium, but measuring extinction is limited by the systematic uncertainties involved in estimating the intrinsic colors to background stars. In this paper we present a new technique, Pnicer, that estimates intrinsic colors and extinction for individual stars using unsupervised machine learning algorithms. This new method aims to be free from any priors with respect to the column density and intrinsic color distribution. It is applicable to any combination of parameters and works in arbitrary numbers of dimensions. Furthermore, it is not restricted to color space. Extinction toward single sources is determined by fitting Gaussian mixture models along the extinction vector to (extinction-free) control field observations. In this way it becomes possible to describe the extinction for observed sources with probability densities, rather than a single value. Pnicer effectively eliminates known biases found in similar methods and outperforms them in cases of deep observational data where the number of background galaxies is significant, or when a large number of parameters is used to break degeneracies in the intrinsic color distributions. This new method remains computationally competitive, making it possible to correctly de-redden millions of sources within a matter of seconds. With the ever-increasing number of large-scale high-sensitivity imaging surveys, Pnicer offers a fast and reliable way to efficiently calculate extinction for arbitrary parameter combinations without prior information on source characteristics. The Pnicer software package also offers access to the well-established Nicer technique in a simple unified interface and is capable of building extinction maps including the Nicest correction for cloud substructure. Pnicer is offered to the community as an open-source software solution and is entirely written in Python.

  15. Session Report - S. Voinis (Andra)

    International Nuclear Information System (INIS)

    Voinis, Sylvie

    2014-01-01

    The session addressed key issues related to the industrial feasibility of construction. It covered the implementer and regulator points of view. The conclusions derive from three presentations completed by the outcomes of six WG. At the Morsleben Repository, Germany, the licensing of the closure of the repository has been initiated by BfS. The closure concept is based on extensive backfilling with salt concrete complemented by seals. In order to demonstrate the feasibility of constructing such a seal structure an in-situ experiment is performed in a drift of the repository. In the UK, the framework for implementing geological disposal of the higher activity radioactive waste is described in the White Paper published by the UK Government in June 2008. The process to site a facility will be staged and based on voluntarism and partnership with local communities. This process is in its early stage. The paper outlines the work being undertaken by the NDA. In canada, Ontario Power Generation (OPG) has submitted information required for a CNSC licence to prepare the site and construct a DGR for the disposal of low and intermediate level waste from the operation of their nuclear power reactors. That submission includes an Environmental Impact Statement (EIS), as required for a Panel Review under the Canadian Environmental Assessment Act (CEAA), and the information required for a licence application under the NSCA Regulations. Discussions between the proponent and the regulator in the pre-licensing phase, clarified CNSC expectations for the characterization of the site and for the development of the EIS and application. They also helped to ensure that OPG understood these expectations. Outcomes WG session-1: - Start with construction but during operational phase: Simultaneous construction and operation activities. - Need for technical requirements/criteria: So that it can be judged whether 'products' meet the requirements; LT safety issues to be considered during

  16. Synchrony in Dyadic Psychotherapy Sessions

    Science.gov (United States)

    Ramseyer, Fabian; Tschacher, Wolfgang

    Synchrony is a multi-faceted concept used in diverse domains such as physics, biology, and the social sciences. This chapter reviews some of the evidence of nonverbal synchrony in human communication, with a main focus on the role of synchrony in the psychotherapeutic setting. Nonverbal synchrony describes coordinated behavior of patient and therapist. Its association with empathy, rapport and the therapeutic relationship has been pointed out repeatedly, yet close evaluation of empirical studies suggests that the evidence remains inconclusive. Particularly in naturalistic studies, research with quantitative measures of synchrony is still lacking. We introduce a new empirical approach for the study of synchrony in psychotherapies under field conditions: Motion Energy Analysis (MEA). This is a video-based algorithm that quantifies the amount of movement in freely definable regions of interest. Our statistical analysis detects synchrony on a global level, irrespective of the specific body parts moving. Synchrony thus defined can be considered as a general measure of movement coordination between interacting individuals. Data from a sequence of N = 21 therapy sessions taken from one psychotherapy dyad shows a high positive relationship between synchrony and the therapeutic bond. Nonverbal synchrony can thus be considered a promising concept for research on the therapeutic alliance. Further areas of application are discussed.

  17. Effect of using pump on postoperative pleural effusion in the patients that underwent CABG

    Directory of Open Access Journals (Sweden)

    Mehmet Özülkü

    2015-08-01

    Full Text Available Abstract Objective: The present study investigated effect of using pump on postoperative pleural effusion in patients who underwent coronary artery bypass grafting. Methods: A total of 256 patients who underwent isolated coronary artery bypass grafting surgery in the Cardiovascular Surgery clinic were enrolled in the study. Jostra-Cobe (Model 043213 105, VLC 865, Sweden heart-lung machine was used in on-pump coronary artery bypass grafting. Off-pump coronary artery bypass grafting was performed using Octopus and Starfish. Proximal anastomoses to the aorta in both on-pump and off-pump techniques were performed by side clamps. The patients were discharged from the hospital between postoperative day 6 and day 11. Results: The incidence of postoperative right pleural effusion and bilateral pleural effusion was found to be higher as a count in Group 1 (on-pump as compared to Group 2 (off-pump. But the difference was not statistically significant [P>0.05 for right pleural effusion (P=0.893, P>0.05 for bilateral pleural effusion (P=0.780]. Left pleural effusion was encountered to be lower in Group 2 (off-pump. The difference was found to be statistically significant (P<0.05, P=0.006. Conclusion: Under the light of these results, it can be said that left pleural effusion is less prevalent in the patients that underwent off-pump coronary artery bypass grafting when compared to the patients that underwent on-pump coronary artery bypass grafting.

  18. Dysphagia among Adult Patients who Underwent Surgery for Esophageal Atresia at Birth

    Directory of Open Access Journals (Sweden)

    Valérie Huynh-Trudeau

    2015-01-01

    Full Text Available BACKGROUND: Clinical experiences of adults who underwent surgery for esophageal atresia at birth is limited. There is some evidence that suggests considerable long-term morbidity, partly because of dysphagia, which has been reported in up to 85% of adult patients who undergo surgery for esophageal atresia. The authors hypothesized that dysphagia in this population is caused by dysmotility and/or anatomical anomalies.

  19. Biogeographic and bathymetric determinants of brachiopod extinction and survival during the Late Ordovician mass extinction

    DEFF Research Database (Denmark)

    Finnegan, Seth; Mac Ørum Rasmussen, Christian; Harper, David A. T.

    2016-01-01

    The Late Ordovician mass extinction (LOME) coincided with dramatic climate changes, but there are numerous ways in which these changes could have driven marine extinctions. We use a palaeobiogeographic database of rhynchonelliform brachiopods to examine the selectivity of Late Ordovician......–Early Silurian genus extinctions and evaluate which extinction drivers are best supported by the data. The first (latest Katian) pulse of the LOME preferentially affected genera restricted to deeper waters or to relatively narrow (less than 35°) palaeolatitudinal ranges. This pattern is only observed...... in the latest Katian, suggesting that it reflects drivers unique to this interval. Extinction of exclusively deeper-water genera implies that changes in water mass properties such as dissolved oxygen content played an important role. Extinction of genera with narrow latitudinal ranges suggests that interactions...

  20. Hospital autopsy: Endangered or extinct?

    Science.gov (United States)

    Turnbull, Angus; Osborn, Michael; Nicholas, Nick

    2015-08-01

    To determine the hospital autopsy rate for the UK in 2013. A study of data from a 'Freedom of Information' request to all (n=186) acute NHS Trusts within England (n=160), NHS Boards in Scotland (n=14) and Wales (n=7) and Social Care Trusts in Northern Ireland (n=5). Hospital autopsy rates were calculated from the number of hospital autopsies performed in 2013 as a percentage of total inpatient deaths in the Trust that year. The UK response rate was 99% (n=184), yielding a mean autopsy rate of 0.69%. The mean rates were 0.51% (England), 2.13% (Scotland), 0.65% (Wales) and 0.46% (Northern Ireland). 23% (n=38) of all included respondents had a rate of 0% and 86% (n=143) a rate less than 1%. The decline in hospital autopsy has continued relentlessly and, for better or for worse, the practice is on the verge of extinction in the UK. The study highlights to health professionals and policy makers the magnitude of this decline. Further research should investigate the impact of this on patient safety, clinical audit, public health and medical education. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  1. Extinction from a rationalist perspective.

    Science.gov (United States)

    Gallistel, C R

    2012-05-01

    The merging of the computational theory of mind and evolutionary thinking leads to a kind of rationalism, in which enduring truths about the world have become implicit in the computations that enable the brain to cope with the experienced world. The dead reckoning computation, for example, is implemented within the brains of animals as one of the mechanisms that enables them to learn where they are (Gallistel, 1990, 1995). It integrates a velocity signal with respect to a time signal. Thus, the manner in which position and velocity relate to one another in the world is reflected in the manner in which signals representing those variables are processed in the brain. I use principles of information theory and Bayesian inference to derive from other simple principles explanations for: (1) the failure of partial reinforcement to increase reinforcements to acquisition; (2) the partial reinforcement extinction effect; (3) spontaneous recovery; (4) renewal; (5) reinstatement; (6) resurgence (aka facilitated reacquisition). Like the principle underlying dead-reckoning, these principles are grounded in analytic considerations. They are the kind of enduring truths about the world that are likely to have shaped the brain's computations. Copyright © 2012 Elsevier B.V. All rights reserved.

  2. Evolution of elderly patients who underwent cardiac surgery with cardiopulmonary bypass

    Directory of Open Access Journals (Sweden)

    Alain Moré Duarte

    2016-01-01

    Full Text Available Introduction: There is a steady increase in the number of elderly patients with severe cardiovascular diseases who require a surgical procedure to recover some quality of life that allows them a socially meaningful existence, despite the risks.Objectives: To analyze the behavior of elderly patients who underwent cardiac surgery with cardiopulmonary bypass.Method: A descriptive, retrospective, cross-sectional study was conducted with patients over 65 years of age who underwent surgery at the Cardiocentro Ernesto Che Guevara, in Santa Clara, from January 2013 to March 2014.Results: In the study, 73.1% of patients were men; and there was a predominance of subjects between 65 and 70 years of age, accounting for 67.3%. Coronary artery bypass graft was the most prevalent type of surgery and had the longest cardiopulmonary bypass times. Hypertension was present in 98.1% of patients. The most frequent postoperative complications were renal dysfunction and severe low cardiac output, with 44.2% and 34.6% respectively.Conclusions: There was a predominance of men, the age group of 65 to 70 years, hypertension, and patients who underwent coronary artery bypass graft with prolonged cardiopulmonary bypass. Renal dysfunction was the most frequent complication.

  3. Acute myocardial infarctation in patients with critical ischemia underwent lower limb revascularization

    Directory of Open Access Journals (Sweden)

    Esdras Marques Lins

    2013-12-01

    Full Text Available BACKGROUND: Atherosclerosis is the main cause of peripheral artery occlusive disease (PAOD of the lower limbs. Patients with PAOD often also have obstructive atherosclerosis in other arterial sites, mainly the coronary arteries. This means that patients who undergo infrainguinal bypass to treat critical ischemia have a higher risk of AMI. There are, however, few reports in the literature that have assessed this risk properly. OBJECTIVE: The aim of this study was to determine the incidence of acute myocardial infarction in patients who underwent infrainguinal bypass to treat critical ischemia of the lower limbs caused by PAOD. MATERIAL AND METHODS: A total of 64 patients who underwent 82 infrainguinal bypass operations, from February 2011 to July 2012 were studied. All patients had electrocardiograms and troponin I blood assays during the postoperative period (within 72 hours. RESULTS: There were abnormal ECG findings and elevated blood troponin I levels suggestive of AMI in five (6% of the 82 operations performed. All five had conventional surgery. The incidence of AMI as a proportion of the 52 conventional surgery cases was 9.6%. Two patients died. CONCLUSION: There was a 6% AMI incidence among patients who underwent infrainguinal bypass due to PAOD. Considering only cases operated using conventional surgery, the incidence of AMI was 9.6%.

  4. Stress before extinction learning enhances and generalizes extinction memory in a predictive learning task.

    Science.gov (United States)

    Meir Drexler, Shira; Hamacher-Dang, Tanja C; Wolf, Oliver T

    2017-05-01

    In extinction learning, the individual learns that a previously acquired association (e.g. between a threat and its predictor) is no longer valid. This learning is the principle underlying many cognitive-behavioral psychotherapeutic treatments, e.g. 'exposure therapy'. However, extinction is often highly-context dependent, leading to renewal (relapse of extinguished conditioned response following context change). We have previously shown that post-extinction stress leads to a more context-dependent extinction memory in a predictive learning task. Yet as stress prior to learning can impair the integration of contextual cues, here we aim to create a more generalized extinction memory by inducing stress prior to extinction. Forty-nine men and women learned the associations between stimuli and outcomes in a predictive learning task (day 1), extinguished them shortly after an exposure to a stress/control condition (day 2), and were tested for renewal (day 3). No group differences were seen in acquisition and extinction learning, and a renewal effect was present in both groups. However, the groups differed in the strength and context-dependency of the extinction memory. Compared to the control group, the stress group showed an overall reduced recovery of responding to the extinguished stimuli, in particular in the acquisition context. These results, together with our previous findings, demonstrate that the effects of stress exposure on extinction memory depend on its timing. While post-extinction stress makes the memory more context-bound, pre-extinction stress strengthens its consolidation for the acquisition context as well, making it potentially more resistant to relapse. These results have implications for the use of glucocorticoids as extinction-enhancers in exposure therapy. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Interstellar extinction in the Small Magellanic Cloud

    International Nuclear Information System (INIS)

    Nandy, K.; McLachlan, A.; Thompson, G.I.; Morgan, D.H.; Willis, A.J.; Wilson, R.; Gondhalekar, P.M.; Houziaux, L.

    1982-01-01

    IUE observations of three considerably reddened stars located near the core of the Small Magellanic Cloud and of two comparison stars which are also SMC members are presented. This region contains a considerable amount of dust. The UV spectrum of one of the reddened stars (BBB 338) shows the lambda 2200 feature characteristic of the Galactic extinction curve. This absorption feature is not obvious in the UV spectra of the other two reddened stars. Due to lack of a suitable comparison star it has not been possible to measure the UV extinction of BBB 338. The extinction curves derived for the other two reddened SMC members differ from the mean Galactic law in that they exhibit very weak or absent lambda 2200 and much higher values of far-UV extinction. These differences are greater than have been found for stars in the Large Magellanic Cloud, confirming earlier observations by others. (author)

  6. Three Color Particle Optical Extinction Monitor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to design, build and test a multi-color (red, green, blue) particle optical extinction monitor suitable for use in either land or airborne applications....

  7. Are marine and nonmarine extinctions correlated?

    Science.gov (United States)

    Rampino, Michael R.

    Recent papers in Eos have debated the possible relationships between marine mass extinctions, comet showers, and volcanism [Alvarez, 1986; Officer and Grieve, 1986], and ail three might be linked [Rampino, 1987]. Moreover, as Officer and Grieve [ 1986] point out, various other causes have been suggested for given extinction events, including changes in climate, ocean circulation, and sea level fluctuations, possibly related to plate tectonics and continental positions. Also under debate is the issue of whether mass extinctions were gradual, stepped, or geologically sudden events (see, for example, Hut et al. [1987]). A missing ingredient thus far in these debates has been the record of faunal diversity of nonmarine animals. Does this show any agreement with the marine extinction record?

  8. Therapeutic Effects of Extinction Learning as a Model of Exposure Therapy in Rats

    Science.gov (United States)

    Fucich, Elizabeth A; Paredes, Denisse; Morilak, David A

    2016-01-01

    Current treatments for stress-related psychiatric disorders, such as depression and posttraumatic stress disorder (PTSD), are inadequate. Cognitive behavioral psychotherapies, including exposure therapy, are an alternative to pharmacotherapy, but the neurobiological mechanisms are unknown. Preclinical models demonstrating therapeutic effects of behavioral interventions are required to investigate such mechanisms. Exposure therapy bears similarity to extinction learning. Thus, we investigated the therapeutic effects of extinction learning as a behavioral intervention to model exposure therapy in rats, testing its effectiveness in reversing chronic stress-induced deficits in cognitive flexibility and coping behavior that resemble dimensions of depression and PTSD. Rats were fear-conditioned by pairing a tone with footshock, and then exposed to chronic unpredictable stress (CUS) that induces deficits in cognitive set-shifting and active coping behavior. They then received an extinction learning session as a therapeutic intervention by repeated exposure to the tone with no shock. Effects on cognitive flexibility and coping behavior were assessed 24 h later on the attentional set-shifting test or shock-probe defensive burying test, respectively. Extinction reversed the CUS-induced deficits in cognitive flexibility and coping behavior, and increased phosphorylation of ribosomal protein S6 in the medial prefrontal cortex (mPFC) of stress-compromised rats, suggesting a role for activity-dependent protein synthesis in the therapeutic effect. Inhibiting protein synthesis by microinjecting anisomycin into mPFC blocked the therapeutic effect of extinction on cognitive flexibility. These results demonstrate the utility of extinction as a model by which to study mechanisms underlying exposure therapy, and suggest these mechanisms involve protein synthesis in the mPFC, the further study of which may identify novel therapeutic targets. PMID:27417516

  9. Interstellar Silicon Depletion and the Ultraviolet Extinction

    Science.gov (United States)

    Mishra, Ajay; Li, Aigen

    2018-01-01

    Spinning small silicate grains were recently invoked to account for the Galactic foreground anomalous microwave emission. These grains, if present, will absorb starlight in the far ultraviolet (UV). There is also renewed interest in attributing the enigmatic 2175 Å interstellar extinction bump to small silicates. To probe the role of silicon in the UV extinction, we explore the relations between the amount of silicon required to be locked up in silicates [Si/H]dust and the 2175 Å bump or the far-UV extinction rise, based on an analysis of the extinction curves along 46 Galactic sightlines for which the gas-phase silicon abundance [Si/H]gas is known. We derive [Si/H]dust either from [Si/H]ISM - [Si/H]gas or from the Kramers- Kronig relation which relates the wavelength-integrated extinction to the total dust volume, where [Si/H]ISM is the interstellar silicon reference abundance and taken to be that of proto-Sun or B stars. We also derive [Si/H]dust from fi�tting the observed extinction curves with a mixture of amorphous silicates and graphitic grains. We fi�nd that in all three cases [Si/H]dust shows no correlation with the 2175 Å bump, while the carbon depletion [C/H]dust tends to correlate with the 2175 Å bump. This supports carbon grains instead of silicates as the possible carrier of the 2175 Å bump. We also �find that neither [Si/H]dust nor [C/H]dust alone correlates with the far-UV extinction, suggesting that the far-UV extinction is a combined effect of small carbon grains and silicates.

  10. Post-Retrieval Extinction Attenuates Cocaine Memories

    OpenAIRE

    Sartor, Gregory C; Aston-Jones, Gary

    2013-01-01

    Recent studies have shown that post-retrieval extinction training attenuates fear and reward-related memories in both humans and rodents. This noninvasive, behavioral approach has the potential to be used in clinical settings to treat maladaptive memories that underlie several psychiatric disorders, including drug addiction. However, few studies to date have used a post-retrieval extinction approach to attenuate addiction-related memories. In the current study, we attempted to disrupt cocaine...

  11. Demography and the extinction of European Neanderthals

    DEFF Research Database (Denmark)

    Sørensen, Bent

    2011-01-01

    Causes previously suggested for the sudden extinction of Neanderthals (Homo neanderthalensis) in Europe, starting around 35,000 years ago, comprise food shortage, climatic effects and violence from Modern Humans. The aim here is to formulate a demographic model with reconstructed fertility...... Human newcomers during the last part of the period. The conclusion is that other reasons for extinction than climate or starvation must be sought....

  12. Software fires detection and extinction for forest

    Directory of Open Access Journals (Sweden)

    Juan Carlos García Seco

    2008-12-01

    Full Text Available This article shows the most usual fire detection and forest extinction application technologies at present. We will see all different methods used by these applications that can be found in the Market and some examples. Also, some basic questions about the most influent parameters when a fire must be extinct are shown. Finally, after having shown all the technologies, we will build a model about an intelligent system which not only detects, but also extinguish wildfires.

  13. Ecological and evolutionary legacy of megafauna extinctions.

    Science.gov (United States)

    Galetti, Mauro; Moleón, Marcos; Jordano, Pedro; Pires, Mathias M; Guimarães, Paulo R; Pape, Thomas; Nichols, Elizabeth; Hansen, Dennis; Olesen, Jens M; Munk, Michael; de Mattos, Jacqueline S; Schweiger, Andreas H; Owen-Smith, Norman; Johnson, Christopher N; Marquis, Robert J; Svenning, Jens-Christian

    2017-10-09

    For hundreds of millions of years, large vertebrates (megafauna) have inhabited most of the ecosystems on our planet. During the late Quaternary, notably during the Late Pleistocene and the early Holocene, Earth experienced a rapid extinction of large, terrestrial vertebrates. While much attention has been paid to understanding the causes of this massive megafauna extinction, less attention has been given to understanding the impacts of loss of megafauna on other organisms with whom they interacted. In this review, we discuss how the loss of megafauna disrupted and reshaped ecological interactions, and explore the ecological consequences of the ongoing decline of large vertebrates. Numerous late Quaternary extinct species of predators, parasites, commensals and mutualistic partners were associated with megafauna and were probably lost due to their strict dependence upon them (co-extinctions). Moreover, many extant species have megafauna-adapted traits that provided evolutionary benefits under past megafauna-rich conditions, but are now of no or limited use (anachronisms). Morphological evolution and behavioural changes allowed some of these species partially to overcome the absence of megafauna. Although the extinction of megafauna led to a number of co-extinction events, several species that likely co-evolved with megafauna established new interactions with humans and their domestic animals. Species that were highly specialized in interactions with megafauna, such as large predators, specialized parasites, and large commensalists (e.g. scavengers, dung beetles), and could not adapt to new hosts or prey were more likely to die out. Partners that were less megafauna dependent persisted because of behavioural plasticity or by shifting their dependency to humans via domestication, facilitation or pathogen spill-over, or through interactions with domestic megafauna. We argue that the ongoing extinction of the extant megafauna in the Anthropocene will catalyse another

  14. The extinction of the West African lion: whose responsibility?

    NARCIS (Netherlands)

    Nollkaemper, A.

    2014-01-01

    A recently published study showed that the lion in West Africa is now critically endangered and faces extinction. From one angle, this would be just one of the large (though unknown) number of species that has previously faced extinction or has even become extinct. But the risk of extinction of some

  15. Characterizing and modeling web sessions with applications

    OpenAIRE

    Chiarandini, Luca

    2014-01-01

    This thesis focuses on the analysis and modeling of web sessions, groups of requests made by a single user for a single navigation purpose. Understanding how people browse through websites is important, helping us to improve interfaces and provide to better content. After first conducting a statistical analysis of web sessions, we go on to present algorithms to summarize and model web sessions. Finally, we describe applications that use novel browsing methods, in particular parallel...

  16. Multiparty Session Types as Coherence Proofs

    DEFF Research Database (Denmark)

    Carbone, Marco; Montesi, Fabrizio; Schürmann, Carsten

    2015-01-01

    We propose a Curry-Howard correspondence between a language for programming multiparty sessions and a generalisation of Classical Linear Logic (CLL). In this framework, propositions correspond to the local behaviour of a participant in a multiparty session type, proofs to processes, and proof nor...... in a multiparty session. We prove the soundness of our model by showing the admissibility of our new rule, which entails deadlock-freedom via our correspondence....

  17. How does climate change cause extinction?

    Science.gov (United States)

    Cahill, Abigail E; Aiello-Lammens, Matthew E; Fisher-Reid, M Caitlin; Hua, Xia; Karanewsky, Caitlin J; Ryu, Hae Yeong; Sbeglia, Gena C; Spagnolo, Fabrizio; Waldron, John B; Warsi, Omar; Wiens, John J

    2013-01-07

    Anthropogenic climate change is predicted to be a major cause of species extinctions in the next 100 years. But what will actually cause these extinctions? For example, will it be limited physiological tolerance to high temperatures, changing biotic interactions or other factors? Here, we systematically review the proximate causes of climate-change related extinctions and their empirical support. We find 136 case studies of climatic impacts that are potentially relevant to this topic. However, only seven identified proximate causes of demonstrated local extinctions due to anthropogenic climate change. Among these seven studies, the proximate causes vary widely. Surprisingly, none show a straightforward relationship between local extinction and limited tolerances to high temperature. Instead, many studies implicate species interactions as an important proximate cause, especially decreases in food availability. We find very similar patterns in studies showing decreases in abundance associated with climate change, and in those studies showing impacts of climatic oscillations. Collectively, these results highlight our disturbingly limited knowledge of this crucial issue but also support the idea that changing species interactions are an important cause of documented population declines and extinctions related to climate change. Finally, we briefly outline general research strategies for identifying these proximate causes in future studies.

  18. Secure Execution of Distributed Session Programs

    Directory of Open Access Journals (Sweden)

    Nuno Alves

    2011-10-01

    Full Text Available The development of the SJ Framework for session-based distributed programming is part of recent and ongoing research into integrating session types and practical, real-world programming languages. SJ programs featuring session types (protocols are statically checked by the SJ compiler to verify the key property of communication safety, meaning that parties engaged in a session only communicate messages, including higher-order communications via session delegation, that are compatible with the message types expected by the recipient. This paper presents current work on security aspects of the SJ Framework. Firstly, we discuss our implementation experience from improving the SJ Runtime platform with security measures to protect and augment communication safety at runtime. We implement a transport component for secure session execution that uses a modified TLS connection with authentication based on the Secure Remote Password (SRP protocol. The key technical point is the delicate treatment of secure session delegation to counter a previous vulnerability. We find that the modular design of the SJ Runtime, based on the notion of an Abstract Transport for session communication, supports rapid extension to utilise additional transports whilst separating this concern from the application-level session programming task. In the second part of this abstract, we formally prove the target security properties by modelling the extended SJ delegation protocols in the pi-calculus.

  19. Extinction rates in North American freshwater fishes, 1900-2010

    Science.gov (United States)

    Burkhead, Noel M.

    2012-01-01

    Widespread evidence shows that the modern rates of extinction in many plants and animals exceed background rates in the fossil record. In the present article, I investigate this issue with regard to North American freshwater fishes. From 1898 to 2006, 57 taxa became extinct, and three distinct populations were extirpated from the continent. Since 1989, the numbers of extinct North American fishes have increased by 25%. From the end of the nineteenth century to the present, modern extinctions varied by decade but significantly increased after 1950 (post-1950s mean = 7.5 extinct taxa per decade). In the twentieth century, freshwater fishes had the highest extinction rate worldwide among vertebrates. The modern extinction rate for North American freshwater fishes is conservatively estimated to be 877 times greater than the background extinction rate for freshwater fishes (one extinction every 3 million years). Reasonable estimates project that future increases in extinctions will range from 53 to 86 species by 2050.

  20. Pre-adolescent and adolescent mice are less sensitive to the effects of acute nicotine on extinction and spontaneous recovery.

    Science.gov (United States)

    Kutlu, Munir Gunes; Zeid, Dana; Tumolo, Jessica M; Gould, Thomas J

    2018-04-01

    Adolescence is a period of high risk for the initiation of nicotine product usage and exposure to traumatic events. In parallel, nicotine exposure has been found to age-dependently modulate acquisition of contextual fear memories; however, it is unknown if adolescent nicotine exposure alters extinction of fear related memories. Age-related differences in sensitivity to the effects of nicotine on fear extinction could increase or decrease susceptibility to anxiety disorders. In this study, we examined the effects of acute nicotine administration on extinction and spontaneous recovery of contextual fear memories in pre-adolescent (PND 23), late adolescent (PND 38), and adult (PND 53) C57B6/J mice. Mice were first trained in a background contextual fear conditioning paradigm and given an intraperitoneal injection of one of four doses of nicotine (0.045, 0.09, 0.18, or 0.36mg/kg, freebase) prior to subsequent extinction or spontaneous recovery sessions. Results indicated that all acute nicotine doses impaired extinction of contextual fear in adult mice. Late adolescent mice exhibited impaired extinction of contextual fear only following higher doses of acute nicotine, and extinction of contextual fear was unaffected by acute nicotine exposure in pre-adolescent mice. Finally, acute nicotine exposure enhanced spontaneous recovery of fear memory, but only in adult mice. Overall, our results suggest that younger mice were less sensitive to nicotine's impairing effects on extinction of contextual fear and to nicotine's enhancing effects on spontaneous recovery of contextual fear memory. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Age differences in fear retention and extinction in male Sprague-Dawley rats: Effects of ethanol challenge during conditioning

    Science.gov (United States)

    Broadwater, Margaret; Spear, Linda P.

    2013-01-01

    Pavlovian fear conditioning is an ideal model to investigate how learning and memory are influenced by alcohol use during adolescence because the neural mechanisms involved have been studied extensively. In Exp 1, adolescent and adult male Sprague-Dawley rats were non-injected or injected with saline, 1 or 1.5 g/kg ethanol intraperitoneally 10 minutes prior to tone or context conditioning. Twenty-four hours later, animals were tested for tone or context retention and extinction, with examination of extinction retention conducted 24 hours thereafter. In Exp 2, a context extinction session was inserted between the tone conditioning and the tone fear retention/extinction days to reduce pre-CS baseline freezing levels at test. Basal levels of acquisition, fear retention, extinction, and extinction retention after tone conditioning were similar between adolescent and adult rats. In contrast adolescents showed faster context extinction than adults, while again not differing from adults during context acquisition, retention or extinction retention. In terms of ethanol effects, adolescents were less sensitive to ethanol-induced context retention deficits than adults. No age differences emerged in terms of tone fear retention, with ethanol disrupting tone fear retention at both ages in Exp1, but at neither age in Exp 2, a difference seemingly due to group differences in pre-CS freezing during tone testing in Exp 1, but not Exp 2. These results suggest that age differences in the acute effects of ethanol on cognitive function are task-specific, and provide further evidence for age differences cognitive functioning in a task thought to be hippocampally-related. PMID:23810415

  2. Talking to the senses: Modulation of tactile extinction through hypnotic suggestion

    Directory of Open Access Journals (Sweden)

    Angelo eMaravita

    2012-07-01

    Full Text Available Brain damage can significantly impair the processing of sensory events. In particular, patients affected by extinction to double bilateral stimulations, show reduced awareness of stimuli delivered in the space contralateral to the brain lesion, when these are presented in competition with ipsilesional ones. The present work shows that hypnotic suggestion can temporarily improve tactile extinction. Patient EB showed an improved detection of contralesional targets after a single 20-minute hypnosis session, during which specific suggestions were delivered with the aim of increasing her insight into somatosensory perception on both sides of the body. Simple overt attention orienting towards the contralesional side, or a hypnotic induction procedure not accompanied by specifically aimed suggestions, were not effective in modulating extinction. The present result is the first systematic evidence that hypnosis can temporarily improve a neuropsychological condition, namely extinction, and may open the way for the use of this technique as a fruitful rehabilitative tool for brain-damaged patients affected by neuropsychological deficits.

  3. Bilateral Alternating Auditory Stimulations Facilitate Fear Extinction and Retrieval

    OpenAIRE

    Boukezzi, Sarah; Silva, Catarina; Nazarian, Bruno; Rousseau, Pierre-François; Guedj, Eric; Valenzuela-Moguillansky, Camila; Khalfa, Stéphanie

    2017-01-01

    Disruption of fear conditioning, its extinction and its retrieval are at the core of posttraumatic stress disorder (PTSD). Such deficits, especially fear extinction delay, disappear after alternating bilateral stimulations (BLS) during eye movement desensitization and reprocessing (EMDR) therapy. An animal model of fear recovery, based on auditory cued fear conditioning and extinction learning, recently showed that BLS facilitate fear extinction and fear extinction retrieval. Our goal was to ...

  4. A sphingolipid mechanism for behavioral extinction.

    Science.gov (United States)

    Huston, Joseph P; Kornhuber, Johannes; Mühle, Christiane; Japtok, Lukasz; Komorowski, Mara; Mattern, Claudia; Reichel, Martin; Gulbins, Erich; Kleuser, Burkhard; Topic, Bianca; De Souza Silva, Maria A; Müller, Christian P

    2016-05-01

    Reward-dependent instrumental behavior must continuously be re-adjusted according to environmental conditions. Failure to adapt to changes in reward contingencies may incur psychiatric disorders like anxiety and depression. When an expected reward is omitted, behavior undergoes extinction. While extinction involves active re-learning, it is also accompanied by emotional behaviors indicative of frustration, anxiety, and despair (extinction-induced depression). Here, we report evidence for a sphingolipid mechanism in the extinction of behavior. Rapid extinction, indicating efficient re-learning, coincided with a decrease in the activity of the enzyme acid sphingomyelinase (ASM), which catalyzes turnover of sphingomyelin to ceramide, in the dorsal hippocampus of rats. The stronger the decline in ASM activity, the more rapid was the extinction. Sphingolipid-focused lipidomic analysis showed that this results in a decline of local ceramide species in the dorsal hippocampus. Ceramides shape the fluidity of lipid rafts in synaptic membranes and by that way can control neural plasticity. We also found that aging modifies activity of enzymes and ceramide levels in selective brain regions. Aging also changed how the chronic treatment with corticosterone (stress) or intranasal dopamine modified regional enzyme activity and ceramide levels, coinciding with rate of extinction. These data provide first evidence for a functional ASM-ceramide pathway in the brain involved in the extinction of learned behavior. This finding extends the known cellular mechanisms underlying behavioral plasticity to a new class of membrane-located molecules, the sphingolipids, and their regulatory enzymes, and may offer new treatment targets for extinction- and learning-related psychopathological conditions. Sphingolipids are common lipids in the brain which form lipid domains at pre- and postsynaptic membrane compartments. Here we show a decline in dorsal hippocampus ceramide species together with a

  5. Prevention of stress-impaired fear extinction through neuropeptide s action in the lateral amygdala.

    Science.gov (United States)

    Chauveau, Frédéric; Lange, Maren Denise; Jüngling, Kay; Lesting, Jörg; Seidenbecher, Thomas; Pape, Hans-Christian

    2012-06-01

    Stressful and traumatic events can create aversive memories, which are a predisposing factor for anxiety disorders. The amygdala is critical for transforming such stressful events into anxiety, and the recently discovered neuropeptide S transmitter system represents a promising candidate apt to control these interactions. Here we test the hypothesis that neuropeptide S can regulate stress-induced hyperexcitability in the amygdala, and thereby can interact with stress-induced alterations of fear memory. Mice underwent acute immobilization stress (IS), and neuropeptide S and a receptor antagonist were locally injected into the lateral amygdala (LA) during stress exposure. Ten days later, anxiety-like behavior, fear acquisition, fear memory retrieval, and extinction were tested. Furthermore, patch-clamp recordings were performed in amygdala slices prepared ex vivo to identify synaptic substrates of stress-induced alterations in fear responsiveness. (1) IS increased anxiety-like behavior, and enhanced conditioned fear responses during extinction 10 days after stress, (2) neuropeptide S in the amygdala prevented, while an antagonist aggravated, these stress-induced changes of aversive behaviors, (3) excitatory synaptic activity in LA projection neurons was increased on fear conditioning and returned to pre-conditioning values on fear extinction, and (4) stress resulted in sustained high levels of excitatory synaptic activity during fear extinction, whereas neuropeptide S supported the return of synaptic activity during fear extinction to levels typical of non-stressed animals. Together these results suggest that the neuropeptide S system is capable of interfering with mechanisms in the amygdala that transform stressful events into anxiety and impaired fear extinction.

  6. Single session vs two sessions of flexible ureterosopy (FURS) for dusting of renal pelvic stones 2–3 cm in diameter: Does stone size or hardness play a role in number of sessions to be applied?”

    Science.gov (United States)

    El Hamed, Ahmed Mamdouh Abd; Elmoghazy, Hazem; Aldahshoury, Mohamed; Riad, Ahmed; Mostafa, Mohammed; Farag, Fawzy; Gamal, Wael

    2017-01-01

    Objective To evaluate the stone hardness in predicting the need for single or two sessions of retrograde intrarenal surgery (RIRS) for renal pelvis stones of 2–3 cm in size. Material and methods Ninety-six patients (64 male and 32 female) with only renal stones (2.5±0.3 cm) underwent RIRS using flexible 7.5 Fr ureteroscope (FURS). The stone hardness was evaluated by preoperative non-contrast computed tomography (NCCT). The patients were divided into two groups based on stone hardness: Group I (n=54) (hard stones - Hounsfield Unit (HU) >1000) and group II (n=42) (not hard stone - HU <1000). The stone-free rate, the operative time, any intra or postoperative complications and the need for second sessions of RIRS were evaluated. Results All stones were successfully accessed. Intraoperative complications were not reported. The initial stone-free rate was 40% in Group I and 95% in Group II after a single session (p=0.01). A second session FURS was needed in 32 cases of Group I (40%) where postoperative CT showed significant residual stone fragments of 6±2 mm, and stone-free rate up to 100 percent. On the contrary only 2 cases from Group II underwent second session FURS (p=0.01). The operative times were 75±15 minutes in Group I and 55±13 minutes in Group II (p<0.01). Six patients (4 in group I and 2 in group II) had postoperative high-grade fever (Clavien Grade II). Conclusion Stone hardness had a significant impact on the decision of performing single versus two sessions of FURS for renal pelvic stones of 2–3 cm rather than the stone size alone. PMID:28717539

  7. Single session vs two sessions of flexible ureterosopy (FURS) for dusting of renal pelvic stones 2-3 cm in diameter: Does stone size or hardness play a role in number of sessions to be applied?"

    Science.gov (United States)

    El Hamed, Ahmed Mamdouh Abd; Elmoghazy, Hazem; Aldahshoury, Mohamed; Riad, Ahmed; Mostafa, Mohammed; Farag, Fawzy; Gamal, Wael

    2017-06-01

    To evaluate the stone hardness in predicting the need for single or two sessions of retrograde intrarenal surgery (RIRS) for renal pelvis stones of 2-3 cm in size. Ninety-six patients (64 male and 32 female) with only renal stones (2.5±0.3 cm) underwent RIRS using flexible 7.5 Fr ureteroscope (FURS). The stone hardness was evaluated by preoperative non-contrast computed tomography (NCCT). The patients were divided into two groups based on stone hardness: Group I (n=54) (hard stones - Hounsfield Unit (HU) >1000) and group II (n=42) (not hard stone - HU <1000). The stone-free rate, the operative time, any intra or postoperative complications and the need for second sessions of RIRS were evaluated. All stones were successfully accessed. Intraoperative complications were not reported. The initial stone-free rate was 40% in Group I and 95% in Group II after a single session (p=0.01). A second session FURS was needed in 32 cases of Group I (40%) where postoperative CT showed significant residual stone fragments of 6±2 mm, and stone-free rate up to 100 percent. On the contrary only 2 cases from Group II underwent second session FURS (p=0.01). The operative times were 75±15 minutes in Group I and 55±13 minutes in Group II (p<0.01). Six patients (4 in group I and 2 in group II) had postoperative high-grade fever (Clavien Grade II). Stone hardness had a significant impact on the decision of performing single versus two sessions of FURS for renal pelvic stones of 2-3 cm rather than the stone size alone.

  8. Voiding patterns of adult patients who underwent hypospadias repair in childhood.

    Science.gov (United States)

    Jaber, Jawdat; Kocherov, Stanislav; Chertin, Leonid; Farkas, Amicur; Chertin, Boris

    2017-02-01

    This study aimed at evaluating the voiding patterns of adult patients who underwent hypospadias repair in childhood. Following IRB approval 103 (22.7%) of 449 adult patients who underwent hypospadias repair between 1978 and 1993 responded to the following questionnaires: International Prostate Symptom Score (I-PSS) and Short Form 12 questionnaire (SF-12). Uroflowmetry (UF) was performed for all patients. The patients were divided into three groups according to the primary meatus localization. Group I had 63 patients (61.5%) treated for glanular hypospadias, group II had 19 patients (18.4%) treated for distal hypospadias, and group III comprised the remaining 21 patients (20.4%) treated for proximal hypospadias. The mean ± SD I-PSS score for all patients who responded to the questionnaire was 2.3 ± 2.4, and UF was 21.1 ± 4.3 mL/s. The patients from groups I and III had fewer urinary symptoms compared with those of the group II: 1.3 ± 1.5, 5.5 ± 2.4, and 1.6 ± 1.4, respectively (p hypospadias repair in childhood had normal or mild voiding disturbance, with no effects on their physical or mental status. Copyright © 2016 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.

  9. [Prognostic Analysis of Breast Cancer Patients Who Underwent Neoadjuvant Chemotherapy Using QOL-ACD].

    Science.gov (United States)

    Fukui, Yasuhiro; Kashiwagi, Shinichiro; Takada, Koji; Goto, Wataru; Asano, Yuka; Morisaki, Tamami; Noda, Satoru; Takashima, Tsutomu; Onoda, Naoyoshi; Hirakawa, Kosei; Ohira, Masaichi

    2017-11-01

    We investigated into association of quality of life(QOL)and prognosis of breast cancer patients who underwent neoadjuvant chemotherapy(NAC). We retrospectively studied 228 patients with breast cancer who were performed NAC during a period between 2007 and 2015. TheQ OL score was measured with"The QOL Questionnaire for Cancer Patients Treated with Anticancer Drugs(QOL-ACD)". We evaluate association between QOL score with antitumor effect and prognosis. Changes in the QOL score between before and after NAC were compared as well. We divided 2 groups by QOL-ACD scoreinto high and low groups. Therapeautic effect of NAC on 75 patients were pathological complete response(pCR). QOL-ACD score was not significantly associated with pCR rate in both high and low groups(p=0.199). High group was significantly associated with higher survival rate in both of disease free survival(p=0.009, logrank)and overall survival(p=0.040, logrank). QOLACD score decreased after NAC in both of pCR and non-pCR patients. In conclusion, QOL evaluation using QOL-ACD could be an indicator of breast cancer patients' prognosis who underwent NAC.

  10. HLA-G regulatory haplotypes and implantation outcome in couples who underwent assisted reproduction treatment.

    Science.gov (United States)

    Costa, Cynthia Hernandes; Gelmini, Georgia Fernanda; Wowk, Pryscilla Fanini; Mattar, Sibelle Botogosque; Vargas, Rafael Gustavo; Roxo, Valéria Maria Munhoz Sperandio; Schuffner, Alessandro; Bicalho, Maria da Graça

    2012-09-01

    The role of HLA-G in several clinical conditions related to reproduction has been investigated. Important polymorphisms have been found within the 5'URR and 3'UTR regions of the HLA-G promoter. The aim of the present study was to investigate 16 SNPs in the 5'URR and 14-bp insertion/deletion (ins/del) polymorphism located in the 3'UTR region of the HLA-G gene and its possible association with the implantation outcome in couples who underwent assisted reproduction treatments (ART). The case group was composed of 25 ART couples. Ninety-four couples with two or more term pregnancies composed the control group. Polymorphism haplotype frequencies of the HLA-G were determined for both groups. The Haplotype 5, Haplotype 8 and Haplotype 11 were absolute absence in ART couples. The HLA-G*01:01:02a, HLA-G*01:01:02b alleles and the 14-bp ins polymorphism, Haplotype 2, showed an increased frequency in case women and similar distribution between case and control men. However, this susceptibility haplotype is significantly presented in case women and in couple with failure implantation after treatment, which led us to suggest a maternal effect, associated with this haplotype, once their presence in women is related to a higher number of couples who underwent ART. Copyright © 2012. Published by Elsevier Inc.

  11. Sarcopenia: a new predictor of postoperative complications for elderly gastric cancer patients who underwent radical gastrectomy.

    Science.gov (United States)

    Zhou, Chong-Jun; Zhang, Feng-Min; Zhang, Fei-Yu; Yu, Zhen; Chen, Xiao-Lei; Shen, Xian; Zhuang, Cheng-Le; Chen, Xiao-Xi

    2017-05-01

    A geriatric assessment is needed to identify high-risk elderly patients with gastric cancer. However, the current geriatric assessment has been considered to be either time-consuming or subjective. The present study aimed to investigate the predictive effect of sarcopenia on the postoperative complications for elderly patients who underwent radical gastrectomy. We conducted a prospective study of patients who underwent radical gastrectomy from August 2014 to December 2015. Computed tomography-assessed lumbar skeletal muscle, handgrip strength, and gait speed were measured to define sarcopenia. Sarcopenia was present in 69 of 240 patients (28.8%) and was associated with lower body mass index, lower serum albumin, lower hemoglobin, and higher nutritional risk screening 2002 scores. Postoperative complications significantly increased in the sarcopenic patients (49.3% versus 24.6%, P sarcopenia (odds ratio: 2.959, 95% CI: 1.629-5.373, P Sarcopenia, presented as a new geriatric assessment factor, was a strong and independent risk factor for postoperative complications of elderly patients with gastric cancer. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Circulating S100B and Adiponectin in Children Who Underwent Open Heart Surgery and Cardiopulmonary Bypass

    Directory of Open Access Journals (Sweden)

    Alessandro Varrica

    2015-01-01

    Full Text Available Background. S100B protein, previously proposed as a consolidated marker of brain damage in congenital heart disease (CHD newborns who underwent cardiac surgery and cardiopulmonary bypass (CPB, has been progressively abandoned due to S100B CNS extra-source such as adipose tissue. The present study investigated CHD newborns, if adipose tissue contributes significantly to S100B serum levels. Methods. We conducted a prospective study in 26 CHD infants, without preexisting neurological disorders, who underwent cardiac surgery and CPB in whom blood samples for S100B and adiponectin (ADN measurement were drawn at five perioperative time-points. Results. S100B showed a significant increase from hospital admission up to 24 h after procedure reaching its maximum peak (P0.05 have been found all along perioperative monitoring. ADN/S100B ratio pattern was identical to S100B alone with the higher peak at the end of CPB and remained higher up to 24 h from surgery. Conclusions. The present study provides evidence that, in CHD infants, S100B protein is not affected by an extra-source adipose tissue release as suggested by no changes in circulating ADN concentrations.

  13. Effect of different pneumoperitoneum pressure on stress state in patients underwent gynecological laparoscopy

    Directory of Open Access Journals (Sweden)

    Ai-Yun Shen

    2016-10-01

    Full Text Available Objective: To observe the effect of different CO2 pneumoperitoneum pressure on the stress state in patients underwent gynecological laparoscopy. Methods: A total of 90 patients who were admitted in our hospital from February, 2015 to October, 2015 for gynecological laparoscopy were included in the study and divided into groups A, B, and C according to different CO2 pneumoperitoneum pressure. The changes of HR, BP, and PetCO2 during the operation process in the three groups were recorded. The changes of stress indicators before operation (T0, 30 min during operation (T1, and 12 h after operation (T2 were compared. Results: The difference of HR, BP, and PetCO2 levels before operation among the three groups was not statistically significant (P>0.05. HR, BP, and PetCO2 levels 30 min after pneumoperitoneum were significantly elevated when compared with before operation (P0.05. PetCO2 level 30 min after pneumoperitoneum in group B was significantly higher than that in group A (P0.05. Conclusions: Low pneumoperitoneum pressure has a small effect on the stress state in patients underwent gynecological laparoscopy, will not affect the surgical operation, and can obtain a preferable muscular relaxation and vision field; therefore, it can be selected in preference.

  14. Extinction Generates Outcome-Specific Conditioned Inhibition.

    Science.gov (United States)

    Laurent, Vincent; Chieng, Billy; Balleine, Bernard W

    2016-12-05

    Extinction involves altering a previously established predictive relationship between a cue and its outcome by repeatedly presenting that cue alone. Although it is widely accepted that extinction generates some form of inhibitory learning [1-4], direct evidence for this claim has been lacking, and the nature of the associative changes induced by extinction have, therefore, remained a matter of debate [5-8]. In the current experiments, we used a novel behavioral approach that we recently developed and that provides a direct measure of conditioned inhibition [9] to compare the influence of extinguished and non-extinguished cues on choice between goal-directed actions. Using this approach, we provide direct evidence that extinction generates outcome-specific conditioned inhibition. Furthermore, we demonstrate that this inhibitory learning is controlled by the infralimbic cortex (IL); inactivation of the IL using M4 DREADDs abolished outcome-specific inhibition and rendered the cue excitatory. Importantly, we found that context modulated this inhibition. Outside its extinction context, the cue was excitatory and functioned as a specific predictor of its previously associated outcome, biasing choice toward actions earning the same outcome. In its extinction context, however, the cue acted as a specific inhibitor and biased choice toward actions earning different outcomes. Context modulation of these excitatory and inhibitory memories was mediated by the dorsal hippocampus (HPC), suggesting that the HPC and IL act in concert to control the influence of conditioned inhibitors on choice. These findings demonstrate for the first time that extinction turns a cue into a net inhibitor that can influence choice via counterfactual action-outcome associations. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Conservation Risks: When Will Rhinos be Extinct?

    Science.gov (United States)

    Haas, Timothy C; Ferreira, Sam M

    2016-08-01

    We develop a risk intelligence system for biodiversity enterprises. Such enterprises depend on a supply of endangered species for their revenue. Many of these enterprises, however, cannot purchase a supply of this resource and are largely unable to secure the resource against theft in the form of poaching. Because replacements are not available once a species becomes extinct, insurance products are not available to reduce the risk exposure of these enterprises to an extinction event. For many species, the dynamics of anthropogenic impacts driven by economic as well as noneconomic values of associated wildlife products along with their ecological stressors can help meaningfully predict extinction risks. We develop an agent/individual-based economic-ecological model that captures these effects and apply it to the case of South African rhinos. Our model uses observed rhino dynamics and poaching statistics. It seeks to predict rhino extinction under the present scenario. This scenario has no legal horn trade, but allows live African rhino trade and legal hunting. Present rhino populations are small and threatened by a rising onslaught of poaching. This present scenario and associated dynamics predicts continued decline in rhino population size with accelerated extinction risks of rhinos by 2036. Our model supports the computation of extinction risks at any future time point. This capability can be used to evaluate the effectiveness of proposed conservation strategies at reducing a species' extinction risk. Models used to compute risk predictions, however, need to be statistically estimated. We point out that statistically fitting such models to observations will involve massive numbers of observations on consumer behavior and time-stamped location observations on thousands of animals. Finally, we propose Big Data algorithms to perform such estimates and to interpret the fitted model's output.

  16. Ann Arbor Session I: Breaking Ground.

    Science.gov (United States)

    Music Educators Journal, 1979

    1979-01-01

    Summarizes the first session of the National Symposium on the Applications of Psychology to the Teaching and Learning of Music held at Ann Arbor from October 30 to November 2, 1978. Sessions concerned auditory perception, motor learning, child development, memory and information processing, and affect and motivation. (SJL)

  17. Summary of southeastern group breakout sessions

    Science.gov (United States)

    Bob Ford; Charles P. Nicholson

    1993-01-01

    The breakout sessions held by the southeastern representatives at the Partners In Flight meeting in Colorado were extremely well attended Most states were represented, as well as several federal agencies (including USFS, USFWS, TVA, EPA), and non-government organizations. Two sessions were held, one to discuss a strategy of management by...

  18. Multiparty session types as coherence proofs

    DEFF Research Database (Denmark)

    Carbone, Marco; Montesi, Fabrizio; Schürmann, Carsten

    2017-01-01

    We propose a Curry–Howard correspondence between a language for programming multiparty sessions and a generalisation of Classical Linear Logic (CLL). In this framework, propositions correspond to the local behaviour of a participant in a multiparty session type, proofs to processes, and proof nor...

  19. Summary of the session on other effects

    International Nuclear Information System (INIS)

    Chao, A.

    1997-07-01

    The theme of this workshop is to discuss the effects of foreign particles on the native beam in a storage ring. This paper summarizes the session on effects not covered in sessions on fast ion instability, electron cloud instability, and cures. The topics discussed are the beam, the foreign particle, how are foreign particles trapped, and how do foreign particles and beam couple

  20. Summary of sessions on experimental facilities

    International Nuclear Information System (INIS)

    Arvieux, J.; Walcher, T.

    1991-01-01

    The contributions and discussions on the session Present Status and Future Perspectives in the Experimental Activities are summarized. In this session the points of convergence and the complementarity for the study of Few Body Systems with strong and electromagnetic probes were apparent. This aspect is emphasized

  1. Client Introversion and Counseling Session Impact.

    Science.gov (United States)

    Nocita, Andrew; Stiles, William B.

    1986-01-01

    Examined impact of counseling sessions as a function of clients' personality characteristics. Results indicated introverted clients rated their sessions as uncomfortable, unpleasant, tense, rough, and difficult and rated their postsession mood as relatively unfriendly, uncertain, sad, angry, and afraid. Conversely, extroverted clients rated their…

  2. Secure Implementations for Typed Session Abstractions

    NARCIS (Netherlands)

    Corin, R.J.; Deniélou, Pierre-Malo; Fournet, Cédric; Bhargavan, Karthikeyan; Leifer, James; Focardi, R.

    Distributed applications can be structured as parties that exchange messages according to some pre-arranged communication patterns. These sessions (or contracts, or protocols) simplify distributed programming: when coding a role for a given session, each party just has to follow the intended message

  3. Factors Influencing Number of Physiotherapy Treatment Sessions ...

    African Journals Online (AJOL)

    Little is known about the influence of physiotherapists' characteristics and treatment modalities on the number of treatment sessions in Nigeria. This study was designed to evaluate the factors influencing the number of treatment sessions for patients with low back pain (LBP). Three hundred and eleven practising ...

  4. Spanning a multimedia session across multiple devices

    NARCIS (Netherlands)

    Aartse Tuijn, Jasper; Bijwaard, D.

    2008-01-01

    This paper describes an innovative solution that allows a multimedia session to be distributed over multiple devices that are in close proximity to a user. This would typically be useful when a user engaged in an audio/video conference enters a meeting room. Upon entering, all media session

  5. Summary of Technical Sessions - Summary and Recommendations

    International Nuclear Information System (INIS)

    2013-01-01

    Technical Session 1 - Development achievements of BEPU methods and State of the Art: The objective of this session was to present the different approaches dealing with Best Estimate codes and uncertainties evaluations. Existing methods were summarized and different papers were focused on specific methods stressing their bases, peculiarities, advantages and limitations. As a result of the session a picture of the current State of the Art was obtained. The session comprised six papers. Technical Session 2 - International comparative activities: This session had as a main objective to review the activities launched in the past and present from the NEA in connection with BEPU methods, with focus on the applicability of conclusions derived from former benchmarks like UMS, the main outcomes of the recently finished BEMUSE project, and the objectives and relevance of UAM and PREMIUM projects. The session comprised four papers. Technical Session 3 - Applications: Licensing, safety analysis support, regulatory body views and industry activities: This session focused on the application of current methods in safety analyses. Contributions from industry, technical safety organizations and regulatory bodies were provided. As a result, a view of the penetration of BEPU methods in current safety analyses was obtained, as well as an indication of the evolution in the near future. Elements such as licensing practices, assessment process, etc. were considered. The session comprised nine papers. Technical Session 4. BEPU methods extension to new fields The session addressed the extension of BEPU methods beyond their current use. By now such methods are mainly applied to classic deterministic environment but it is believed that their benefits could be extended to other fields. Seven papers were presented in the session dealing with subjects that fit in the objectives established in the workshop programme. The papers cover areas like: extension to CFD, quantification of global safety

  6. Using session types as an effect system

    Directory of Open Access Journals (Sweden)

    Dominic Orchard

    2016-02-01

    Full Text Available Side effects are a core part of practical programming. However, they are often hard to reason about, particularly in a concurrent setting. We propose a foundation for reasoning about concurrent side effects using sessions. Primarily, we show that session types are expressive enough to encode an effect system for stateful processes. This is formalised via an effect-preserving encoding of a simple imperative language with an effect system into the pi-calculus with session primitives and session types (into which we encode effect specifications. This result goes towards showing a connection between the expressivity of session types and effect systems. We briefly discuss how the encoding could be extended and applied to reason about and control concurrent side effects.

  7. Quantitative analysis of forest fire extinction efficiency

    Directory of Open Access Journals (Sweden)

    Miguel E. Castillo-Soto

    2015-08-01

    Full Text Available Aim of study: Evaluate the economic extinction efficiency of forest fires, based on the study of fire combat undertaken by aerial and terrestrial means. Area of study, materials and methods: Approximately 112,000 hectares in Chile. Records of 5,876 forest fires that occurred between 1998 and 2009 were analyzed. The area further provides a validation sector for results, by incorporating databases for the years 2010 and 2012. The criteria used for measuring extinction efficiency were economic value of forestry resources, Contraction Factor analysis and definition of the extinction costs function. Main results: It is possible to establish a relationship between burnt area, extinction costs and economic losses. The method proposed may be used and adapted to other fire situations, requiring unit costs for aerial and terrestrial operations, economic value of the property to be protected and speed attributes of fire spread in free advance. Research highlights: The determination of extinction efficiency in containment works of forest fires and potential projection of losses, different types of plant fuel and local conditions favoring the spread of fire broaden the admissible ranges of a, φ and Ce considerably.

  8. Neural signals of vicarious extinction learning.

    Science.gov (United States)

    Golkar, Armita; Haaker, Jan; Selbing, Ida; Olsson, Andreas

    2016-10-01

    Social transmission of both threat and safety is ubiquitous, but little is known about the neural circuitry underlying vicarious safety learning. This is surprising given that these processes are critical to flexibly adapt to a changeable environment. To address how the expression of previously learned fears can be modified by the transmission of social information, two conditioned stimuli (CS + s) were paired with shock and the third was not. During extinction, we held constant the amount of direct, non-reinforced, exposure to the CSs (i.e. direct extinction), and critically varied whether another individual-acting as a demonstrator-experienced safety (CS + vic safety) or aversive reinforcement (CS + vic reinf). During extinction, ventromedial prefrontal cortex (vmPFC) responses to the CS + vic reinf increased but decreased to the CS + vic safety This pattern of vmPFC activity was reversed during a subsequent fear reinstatement test, suggesting a temporal shift in the involvement of the vmPFC. Moreover, only the CS + vic reinf association recovered. Our data suggest that vicarious extinction prevents the return of conditioned fear responses, and that this efficacy is reflected by diminished vmPFC involvement during extinction learning. The present findings may have important implications for understanding how social information influences the persistence of fear memories in individuals suffering from emotional disorders. © The Author (2016). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

  9. Fluoxetine Facilitates Fear Extinction Through Amygdala Endocannabinoids.

    Science.gov (United States)

    Gunduz-Cinar, Ozge; Flynn, Shaun; Brockway, Emma; Kaugars, Katherine; Baldi, Rita; Ramikie, Teniel S; Cinar, Resat; Kunos, George; Patel, Sachin; Holmes, Andrew

    2016-05-01

    Pharmacologically elevating brain endocannabinoids (eCBs) share anxiolytic and fear extinction-facilitating properties with classical therapeutics, including the selective serotonin reuptake inhibitor, fluoxetine. There are also known functional interactions between the eCB and serotonin systems and preliminary evidence that antidepressants cause alterations in brain eCBs. However, the potential role of eCBs in mediating the facilitatory effects of fluoxetine on fear extinction has not been established. Here, to test for a possible mechanistic contribution of eCBs to fluoxetine's proextinction effects, we integrated biochemical, electrophysiological, pharmacological, and behavioral techniques, using the extinction-impaired 129S1/Sv1mJ mouse strain. Chronic fluoxetine treatment produced a significant and selective increase in levels of anandamide in the BLA, and an associated decrease in activity of the anandamide-catabolizing enzyme, fatty acid amide hydrolase. Slice electrophysiological recordings showed that fluoxetine-induced increases in anandamide were associated with the amplification of eCB-mediated tonic constraint of inhibitory, but not excitatory, transmission in the BLA. Behaviorally, chronic fluoxetine facilitated extinction retrieval in a manner that was prevented by systemic or BLA-specific blockade of CB1 receptors. In contrast to fluoxetine, citalopram treatment did not increase BLA eCBs or facilitate extinction. Taken together, these findings reveal a novel, obligatory role for amygdala eCBs in the proextinction effects of a major pharmacotherapy for trauma- and stressor-related disorders and anxiety disorders.

  10. Can extinction rates be estimated without fossils?

    Science.gov (United States)

    Paradis, Emmanuel

    2004-07-07

    There is considerable interest in the possibility of using molecular phylogenies to estimate extinction rates. The present study aims at assessing the statistical performance of the birth-death model fitting approach to estimate speciation and extinction rates by comparison to the approach considering fossil data. A simulation-based approach was used. The diversification of a large number of lineages was simulated under a wide range of speciation and extinction rate values. The estimators obtained with fossils performed better than those without fossils. In the absence of fossils (e.g. with a molecular phylogeny), the speciation rate was correctly estimated in a wide range of situations; the bias of the corresponding estimator was close to zero for the largest trees. However, this estimator was substantially biased when the simulated extinction rate was high. On the other hand the estimator of extinction rate was biased in a wide range of situations. Surprisingly, this bias was lesser with medium-sized trees. Some recommendations for interpreting results from a diversification analysis are given. Copyright 2003 Elsevier Ltd.

  11. Mass Extinctions and Biosphere-Geosphere Stability

    Science.gov (United States)

    Rothman, Daniel; Bowring, Samuel

    2015-04-01

    Five times in the past 500 million years, mass extinctions have resulted in the loss of greater than three-fourths of living species. Each of these events is associated with significant environmental change recorded in the carbon-isotopic composition of sedimentary rocks. There are also many such environmental events in the geologic record that are not associated with mass extinctions. What makes them different? Two factors appear important: the size of the environmental perturbation, and the time scale over which it occurs. We show that the natural perturbations of Earth's carbon cycle during the past 500 million years exhibit a characteristic rate of change over two orders of magnitude in time scale. This characteristic rate is consistent with the maximum rate that limits quasistatic (i.e., near steady-state) evolution of the carbon cycle. We identify this rate with marginal stability, and show that mass extinctions occur on the fast, unstable side of the stability boundary. These results suggest that the great extinction events of the geologic past, and potentially a "sixth extinction" associated with modern environmental change, are characterized by common mechanisms of instability.

  12. Disease and the dynamics of extinction.

    Science.gov (United States)

    McCallum, Hamish

    2012-10-19

    Invading infectious diseases can, in theory, lead to the extinction of host populations, particularly if reservoir species are present or if disease transmission is frequency-dependent. The number of historic or prehistoric extinctions that can unequivocally be attributed to infectious disease is relatively small, but gathering firm evidence in retrospect is extremely difficult. Amphibian chytridiomycosis and Tasmanian devil facial tumour disease (DFTD) are two very different infectious diseases that are currently threatening to cause extinctions in Australia. These provide an unusual opportunity to investigate the processes of disease-induced extinction and possible management strategies. Both diseases are apparently recent in origin. Tasmanian DFTD is entirely host-specific but potentially able to cause extinction because transmission depends weakly, if at all, on host density. Amphibian chytridiomycosis has a broad host range but is highly pathogenic only to some populations of some species. At present, both diseases can only be managed by attempting to isolate individuals or populations from disease. Management options to accelerate the process of evolution of host resistance or tolerance are being investigated in both cases. Anthropogenic changes including movement of diseases and hosts, habitat destruction and fragmentation and climate change are likely to increase emerging disease threats to biodiversity and it is critical to further develop strategies to manage these threats.

  13. Session-RPE for quantifying the load of different youth basketball training sessions

    Directory of Open Access Journals (Sweden)

    C Lupo

    2016-12-01

    Full Text Available The aim of the study was to evaluate youth basketball training, verifying the reliability of the session-RPE method in relation to session duration (< and ≥ 80 minutes and workout typology (reduced and high warm-up, conditioning, technical, tactical, game portions within a single session categories. Six male youth basketball players (age, 16.5±0.5 years; height, 195.5±6.75 cm; body mass, 93.9±10.9 kg; and body mass index, 23.6±2.8 kg.m-2 were monitored (HR, type and duration of workouts during 15 (66 individual training sessions (80±26 minutes. Edwards’ HR method was used as a reference measure of internal training load (ITL; the CR-10 RPE scale was administered 30 minutes after the end of each session. The results obtained showed that all comparisons between different session durations and workout portions revealed effects in term of Edwards’ ITLs except for warm-up portions. Moderate to strong relationships between Edwards’ and session- RPE methods emerged for all sessions (r = .85, P < .001, player’s sessions (r range = .79 - .95, P < .001, session durations (< 80 minutes: r = .67, P < .001; ≥ 80 minutes: r = .75, P < .001, and workout portions (r range = .78 - .89, P range = .002 - < .001. The findings indicated that coaches of youth basketball players can successfully use session-RPE to monitor the ITL, regardless of session durations and workout portions.

  14. Hyperresponsiveness of the Neural Fear Network During Fear Conditioning and Extinction Learning in Male Cocaine Users.

    Science.gov (United States)

    Kaag, Anne Marije; Levar, Nina; Woutersen, Karlijn; Homberg, Judith; van den Brink, Wim; Reneman, Liesbeth; van Wingen, Guido

    2016-10-01

    The authors investigated whether cocaine use disorder is associated with abnormalities in the neural underpinnings of aversive conditioning and extinction learning, as these processes may play an important role in the development and persistence of drug abuse. Forty male regular cocaine users and 51 male control subjects underwent a fear conditioning and extinction protocol during functional MRI. Skin conductance response was measured throughout the experiment as an index of conditioned responses. Cocaine users showed hyperresponsiveness of the amygdala and insula during fear conditioning, as well as hyporesponsiveness of the dorsomedial prefrontal cortex during extinction learning. In cocaine users, but not in control subjects, skin conductance responses were positively correlated with responsiveness of the insula, amygdala, and dorsomedial prefrontal cortex during fear conditioning but negatively correlated with responsiveness of the ventromedial prefrontal cortex during extinction learning. Increased sensitivity to aversive conditioned cues in cocaine users might be a risk factor for stress-relief craving in cocaine use disorder. These results support the postulated role of altered aversive conditioning in cocaine use disorder and may be an important step in understanding the role of aversive learning in the pathology of cocaine use disorder.

  15. Post-retrieval extinction in adolescence prevents return of juvenile fear

    Science.gov (United States)

    Jones, Carolyn E.

    2016-01-01

    Traumatic experiences early in life can contribute to the development of mood and anxiety disorders that manifest during adolescence and young adulthood. In young rats exposed to acute fear or stress, alterations in neural development can lead to enduring behavioral abnormalities. Here, we used a modified extinction intervention (retrieval+extinction) during late adolescence (post-natal day 45 [p45]), in rats, to target auditory Pavlovian fear associations acquired as juveniles (p17 and p25). The effects of adolescent intervention were examined by assessing freezing as adults during both fear reacquisition and social transmission of fear from a cagemate. Rats underwent testing or training at three time points across development: juvenile (p17 or p25), adolescent (p45), and adult (p100). Retrieval+extinction during late adolescence prevented social reinstatement and recovery over time of fears initially acquired as juveniles (p17 and p25, respectively). Adolescence was the only time point tested here where retrieval+extinction prevented fear recall of associations acquired 20+ days earlier. PMID:27634147

  16. A Pregnant Woman Who Underwent Laparoscopic Adrenalectomy due to Cushing’s Syndrome

    Directory of Open Access Journals (Sweden)

    Halit Diri

    2014-01-01

    Full Text Available Cushing’s syndrome (CS may lead to severe maternal and fetal morbidities and even mortalities in pregnancy. However, pregnancy complicates the diagnosis and treatment of CS. This study describes a 26-year-old pregnant woman admitted with hypertension-induced headache. Hormonal analyses performed due to her cushingoid phenotype revealed a diagnosis of adrenocorticotropic hormone- (ACTH- independent CS. MRI showed a 3.5 cm adenoma in her right adrenal gland. After preoperative metyrapone therapy, she underwent a successful unilateral laparoscopic adrenalectomy at 14-week gestation. Although she had a temporary postoperative adrenal insufficiency, hormonal analyses showed that she has been in remission since delivery. Findings in this patient, as well as those in previous patients, indicate that pregnancy is not an absolute contraindication for laparoscopic adrenalectomy. Rather, such surgery should be considered a safe and efficient treatment method for pregnant women with cortisol-secreting adrenal adenomas.

  17. Clinical outcomes for 14 consecutive patients with solid pseudopapillary neoplasms who underwent laparoscopic distal pancreatectomy.

    Science.gov (United States)

    Nakamura, Yoshiharu; Matsushita, Akira; Katsuno, Akira; Yamahatsu, Kazuya; Sumiyoshi, Hiroki; Mizuguchi, Yoshiaki; Uchida, Eiji

    2016-02-01

    The postoperative results of laparoscopic distal pancreatectomy for solid pseudopapillary neoplasm of the pancreas (SPN), including the effects of spleen-preserving resection, are still to be elucidated. Of the 139 patients who underwent laparoscopic pancreatectomy for non-cancerous tumors, 14 consecutive patients (average age, 29.6 years; 1 man, 13 women) with solitary SPN who underwent laparoscopic distal pancreatectomy between March 2004 and June 2015 were enrolled. The tumors had a mean diameter of 4.8 cm. Laparoscopic spleen-preserving distal pancreatectomy was performed in eight patients (spleen-preserving group), including two cases involving pancreatic tail preservation, and laparoscopic spleno-distal pancreatectomy was performed in six patients (standard resection group). The median operating time was 317 min, and the median blood loss was 50 mL. Postoperatively, grade B pancreatic fistulas appeared in two patients (14.3%) but resolved with conservative treatment. No patients had postoperative complications, other than pancreatic fistulas, or required reoperation. The median postoperative hospital stay was 11 days, and the postoperative mortality was zero.None of the patients had positive surgical margins or lymph nodes with metastasis. The median follow-up period did not significantly differ between the two groups (20 vs 39 months, P = 0.1368). All of the patients are alive and free from recurrent tumors without major late-phase complications. Laparoscopic distal pancreatectomy might be a suitable treatment for patients with SPN. A spleen-preserving operation is preferable for younger patients with SPN, and this study demonstrated the non-inferiority of the procedure compared to spleno-distal pancreatectomy. © 2015 Japan Society for Endoscopic Surgery, Asia Endosurgery Task Force and John Wiley & Sons Australia, Ltd.

  18. [Patients with astigmatism who underwent cataract surgery by phacoemulsification: toric IOL x asferic IOL?].

    Science.gov (United States)

    Torres Netto, Emilio de Almeida; Gulin, Marina Carvalho; Zapparoli, Marcio; Moreira, Hamilton

    2013-01-01

    Compare the visual acuity of patients who underwent cataract surgery by phacoemulsification with IOL AcrySof(®) toric implantation versus AcrySof(®) IQ and evaluate the reduction of cylindrical diopters (CD) in the postoperative period. Analytical and retrospective study of 149 eyes with 1 or more diopters of regular symmetrical keratometric astigmatism, which underwent cataract surgery by phacoemulsification. The eyes were divided into two groups: the toric group with 85 eyes and the non-toric group with 64 eyes. In the pre-operative phase, topographic data and refraction of each eye to be operated were assessed. In the postoperative phase, refraction and visual acuity with and without correction were measured. The preoperative topographic astigmatism ranged from 1.00 to 5.6 DC in both groups. Average reduction of 1.37 CD (p<0.001) and 0.16 CD (p=0.057) was obtained for the toric and non-toric group when compared to the refractive astigmatism, respectively. Considering visual acuity without correction (NCVA), the toric group presented 44 eyes (51.7%) with NCVA of 0 logMAR (20/20) or 0.1 logMAR (20/25) and the toric group presented 7 eyes (10.93%) with these same NCVA values. The results show that patients with a significant keratometric astigmatism presented visual benefits with the toric IOL implantation. The reduction of the use of optical aids may be obtained provided aberrations of the human eye are corrected more accurately. Currently, phacoemulsification surgery has been used not only for functional improvement, but also as a refraction procedure.

  19. Enteral nutrition is superior to total parenteral nutrition for pancreatic cancer patients who underwent pancreaticoduodenectomy.

    Science.gov (United States)

    Liu, Changli; Du, Zhi; Lou, Cheng; Wu, Chenxuan; Yuan, Qiang; Wang, Jun; Shu, Guiming; Wang, Yijun

    2011-01-01

    To determine the effects of total parenteral nutrition (TPN) and enteral nutrition (EN) on biochemical and clinical outcomes in pancreatic cancer patients who underwent pancreaticoduodenectomy. From the year 2006 to 2008, 60 patients who underwent pancreaticoduodenectomy in Tianjin Third Central Hospital were enrolled in this study. They were randomly divided into the EN group and the TPN group. The biochemical and clinical parameters were recorded and analyzed between the two groups. There was no significant difference in the nutritional status, liver and kidney function, and blood glucose levels between the TPN and EN groups on the preoperative day, the 1st and 3 rd postoperative days. However, on the 7th postoperative day, there was significant difference between the two groups in 24 h urinary nitrogen, serum levels of, total protein (TP), transferrin (TF), alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and γ-glutamyl transpeptadase (GGT), blood urea nitrogen (BUN) and creatinine (Cr). On the 14th postoperative day, there was a significant difference between the two groups in terms of urinary levels of 24 h nitrogen, TP, TF, retinol binding protein, ALT, AST, ALP, GGT, total bilirubin, direct bilirubin, BUN, Cr, and glucose. The incidence of delayed gastric emptying in the EN and TPN groups was 0% and 20%, respectively. Moreover, the incidence of pancreatic fistulas and hemorrhages in the EN group were 3.6% and 3.6%, versus 26.7% and 30% in the TPN group, respectively. EN is better than TPN for pancreatic cancer patients who received pancreaticoduodenectomy.

  20. Vorinostat ameliorates impaired fear extinction possibly via the hippocampal NMDA-CaMKII pathway in an animal model of posttraumatic stress disorder.

    Science.gov (United States)

    Matsumoto, Yasutaka; Morinobu, Shigeru; Yamamoto, Shigeto; Matsumoto, Tomoya; Takei, Shiro; Fujita, Yosuke; Yamawaki, Shigeto

    2013-09-01

    Given that impairment of fear extinction plays a pivotal role in the pathophysiology of posttraumatic stress disorder (PTSD), drugs that facilitate fear extinction may be useful as novel treatments for PTSD. Histone deacetylase (HDAC) inhibitors have recently been shown to enhance fear extinction in animal studies. Using a single prolonged stress (SPS) paradigm, an animal model of PTSD, we examined whether the HDAC inhibitor vorinostat can facilitate fear extinction in rats, and elucidated the mechanism by which vorinostat enhanced fear extinction, focusing on the N-methyl-D-aspartate (NMDA) receptor signals in the hippocampus. Seven days after SPS, rats received contextual fear conditioning, followed by 2-day extinction training. Vorinostat was intraperitoneally injected immediately after second extinction training session. Contextual fear response was assessed 24 h after vorinostat injection. Hippocampal tissues were dissected 2 h after vorinostat injection. The levels of mRNA and protein tested were measured by RT-PCR or western blotting, respectively. Systemic administration of vorinostat with extinction training significantly enhanced fear extinction in SPS rats as compared with the controls. Furthermore, vorinostat enhanced the hippocampal levels of NR2B and calcium/calmodulin kinase II (CaMKII) α and β proteins, accompanied by increases in the levels of acetylated histone H3 and H4. These findings suggest that vorinostat ameliorated the impaired fear extinction in SPS rats, and this effect was associated with an increase in histone acetylation and thereby enhancement of NR2B and CaMKII in the hippocampus. Our results may provide new insight into the molecular and therapeutic mechanisms of PTSD.

  1. Flexible session management in a distributed environment

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Zach; /Wisconsin U., Madison; Bradley, Dan; /Wisconsin U., Madison; Tannenbaum, Todd; /Wisconsin U., Madison; Sfiligoi, Igor; /Fermilab

    2010-01-01

    Many secure communication libraries used by distributed systems, such as SSL, TLS, and Kerberos, fail to make a clear distinction between the authentication, session, and communication layers. In this paper we introduce CEDAR, the secure communication library used by the Condor High Throughput Computing software, and present the advantages to a distributed computing system resulting from CEDAR's separation of these layers. Regardless of the authentication method used, CEDAR establishes a secure session key, which has the flexibility to be used for multiple capabilities. We demonstrate how a layered approach to security sessions can avoid round-trips and latency inherent in network authentication. The creation of a distinct session management layer allows for optimizations to improve scalability by way of delegating sessions to other components in the system. This session delegation creates a chain of trust that reduces the overhead of establishing secure connections and enables centralized enforcement of system-wide security policies. Additionally, secure channels based upon UDP datagrams are often overlooked by existing libraries; we show how CEDAR's structure accommodates this as well. As an example of the utility of this work, we show how the use of delegated security sessions and other techniques inherent in CEDAR's architecture enables US CMS to meet their scalability requirements in deploying Condor over large-scale, wide-area grid systems.

  2. Biotic extinctions by solar flares; and reply

    International Nuclear Information System (INIS)

    Beland, P.; Russell, D.A.; Crutzen, P.J.; Reid, G.C.

    1976-01-01

    Some comments are offered on the paper by Reid and others (nature 259:177 (1976)) in which a mechanism was suggested by which solar protons might catastrophically deplete atmospheric D 3 during a reversal of the Earth's geomagnetic field. Organisms would thereby be exposed to a more intense UV environment, leading to species extinctions. These authors assumed that during a reversal the geomagnetic field effectively disappears for about 1000 years, and also that solar flares sufficiently intense to cause extinctions occur at intervals of 1000 years or more. The validity of these assumptions is here examined using data on geomagnetic reversals identified over the past 75 M years, together with extinction data, and some anomalies are pointed out. A reply by Reid and others is appended. (U.K.)

  3. On the brink between extinction and persistence

    Directory of Open Access Journals (Sweden)

    Bach Lars A

    2008-11-01

    Full Text Available Abstract The nature of size fluctuations is crucial in forecasting future population persistence, independently of whether the variability stems from external forces or from the dynamics of the population renewal process. The risk of intercepting zero is highly dependent on the way the variance of the population size relates to its mean. The minimum population size required for a population not to go extinct can be determined by a scaling equation relating the variance to the arithmetic mean. By the use of a derived expression for the harmonic mean defined by the parameters of the scaling equation we show how it is possible to separate the domains of persistence from those of extinction and to facilitate the identification of populations on the brink of extinction. Reviewers This article was reviewed by Mark W. Schwartz (nominated by Peter Olofsson, Josef Bryja (nominated by Aniko Szabo and Wai-YuanTan. For the full reviews, please go to the Reviewers' Comments section.

  4. Astrophysical life extinctions what killed the dinosaurs?

    CERN Document Server

    Dar, Arnon

    1999-01-01

    Geological records indicate that the exponential diversification of marine and continental life on Earth in the past 500 My was interrupted by many life extinctions. They also indicate that the major mass extinctions were correlated in time with large meteoritic impacts, gigantic volcanic eruptions, sea regressions and drastic changes in global climate. Some of these catastrophes coincided in time. The astrophysical life extinction mechanisms which were proposed so far, in particular, meteoritic impacts, nearby supernova explosions, passage through molecular or dark matter clouds, and Galactic gamma/cosmic ray bursts cannot explain the time coincidences between these catastrophes. However, recent observations suggest that many planetary-mass objects may be present in the outer solar system between the Kuiper belt and the Oort cloud. Gravitational perturbations may occasionally bring them into the inner solar system. Their passage near Earth could have generated gigantic tidal waves, large volcanic eruptions, ...

  5. The fossil record of the sixth extinction.

    Science.gov (United States)

    Plotnick, Roy E; Smith, Felisa A; Lyons, S Kathleen

    2016-05-01

    Comparing the magnitude of the current biodiversity crisis with those in the fossil record is difficult without an understanding of differential preservation. Integrating data from palaeontological databases with information on IUCN status, ecology and life history characteristics of contemporary mammals, we demonstrate that only a small and biased fraction of threatened species (fossil record, compared with 20% of non-threatened species. We find strong taphonomic biases related to body size and geographic range. Modern species with a fossil record tend to be large and widespread and were described in the 19(th) century. The expected magnitude of the current extinction based only on species with a fossil record is about half of that of one based on all modern species; values for genera are similar. The record of ancient extinctions may be similarly biased, with many species having originated and gone extinct without leaving a tangible record. © 2016 John Wiley & Sons Ltd/CNRS.

  6. Extinction dynamics from metastable coexistences in an evolutionary game

    Science.gov (United States)

    Park, Hye Jin; Traulsen, Arne

    2017-10-01

    Deterministic evolutionary game dynamics can lead to stable coexistences of different types. Stochasticity, however, drives the loss of such coexistences. This extinction is usually accompanied by population size fluctuations. We investigate the most probable extinction trajectory under such fluctuations by mapping a stochastic evolutionary model to a problem of classical mechanics using the Wentzel-Kramers-Brillouin (WKB) approximation. Our results show that more abundant types in a coexistence may be more likely to go extinct first, in good agreement with previous results. The distance between the coexistence and extinction points is not a good predictor of extinction either. Instead, the WKB method correctly predicts the type going extinct first.

  7. Interstellar extinction in the Taurus dark clouds

    International Nuclear Information System (INIS)

    Meistas, E.; Straizys, V.

    1981-01-01

    The results of photoelectric photometry of 89 stars in the Vilnius seven-color system in the area of the Taurus dark clouds with corrdinates (1950) 4sup(h)16sup(m)-4sup(h)33sup(m), +16 0 -+20 0 are presented. Photometric spectral types, absolute magnitude, color excesses, interstellar extinctions and distances of the stars are determined. The distance of the dark nebula is found to be 140 pc and is in a good agreement with the distance determined for the dark nebula Khavtassi 286, 278. The average extinction Asub(v) in the investigated area is of the order of 1.4. (author)

  8. Multiple sessions of low-frequency repetitive transcranial magnetic stimulation in focal hand dystonia

    DEFF Research Database (Denmark)

    Kimberley, Teresa Jacobson; Borich, Michael R; Arora, Sanjeev

    2013-01-01

    Purpose: The ability of low-frequency repetitive transcranial magnetic stimulation (rTMS) to enhance intracortical inhibition has motivated its use as a potential therapeutic intervention in focal hand dystonia (FHD). In this preliminary investigation, we assessed the physiologic and behavioral...... effects of multiple sessions of rTMS in FHD. Methods: 12 patients with FHD underwent five daily-sessions of 1 Hz rTMS to contralateral dorsal premotor cortex (dPMC). Patients held a pencil and made movements that did not elicit dystonic symptoms during rTMS. We hypothesized that an active but non...

  9. Study of the seroma volume changes in the patients who underwent Accelerated Partial Breast Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dae Ho; Son, Sang Jun; Mun, Jun Ki; Seo, Seok Jin; Lee, Je Hee [Dept. of Radiation Oncology, Seoul National University Hospital, Seoul (Korea, Republic of)

    2016-06-15

    By analyzing seroma volume changes in the patients who underwent Partial breast radiation therapy after breast conserving surgery, we try to contribute to the improvement of radiotherapy effect. Enrolled 20 patients who underwent partial breast radiation therapy by ViewRay MRIdian System were subject. After seeking for the size of the removed sample in the patients during surgery and obtained seroma volume changes on a weekly basis. On the Basis of acquired volume, it was compared with age, term from start of the first treatment after surgery, BMI (body mass index) and the extracted sample size during surgery. And using the ViewRay MRIdian RTP System, the figure was analyzed by PTV(=seroma volume + margin) to obtain a specific volume of the Partial breast radiation therapy. The changes of seroma volume from MR simulation to the first treatment (a week) is 0~5% in 8, 5~10% in 3, 10 to 15% in 2, and 20% or more in 5 people. Two patients(A, B patient) among subjects showed the biggest change. The A patient's 100% of the prescribed dose volume is 213.08 cc, PTV is 181.93 cc, seroma volume is 15.3 cc in initial plan. However, while seroma volume decreased 65.36% to 5.3 cc, 100% of the prescribed dose volume was reduced to 3.4% to 102.43 cc and PTV also did 43.6% to 102.54 cc. In the case of the B patient, seroma volume decreased 42.57% from 20.2 cc to 11.6 cc. Because of that, 100% of the prescribed dose volume decreased 8.1% and PTV also did to 40%. As the period between the first therapy and surgery is shorter, the patient is elder and the size of sample is smaller than 100 cc, the change grow bigger. It is desirable to establish an adaptive plan according to each patient's changes of seroma volume through continuous observation. Because partial breast patients is more sensitive than WBRT patients about dose conformity in accordance with the volume change.

  10. Effects of acute exercise on fear extinction in rats and exposure therapy in humans: Null findings from five experiments.

    Science.gov (United States)

    Jacquart, Jolene; Roquet, Rheall F; Papini, Santiago; Powers, Mark B; Rosenfield, David; Smits, Jasper A J; Monfils, Marie-H

    2017-08-01

    Exposure therapy is an established learning-based intervention for the treatment of anxiety disorders with an average response rate of nearly 50%, leaving room for improvement. Emerging strategies to enhance exposure therapy in humans and fear extinction retention in animal models are primarily pharmacological. These approaches are limited as many patients report preferring non-pharmacological approaches in therapy. With general cognitive enhancement effects, exercise has emerged as a plausible non-pharmacological augmentation strategy. The present study tested the hypothesis that fear extinction and exposure therapy would be enhanced by a pre-training bout of exercise. We conducted four experiments with rats that involved a standardized conditioning and extinction paradigm and a manipulation of exercise. In a fifth experiment, we manipulated vigorous-intensity exercise prior to a standardized virtual reality exposure therapy session among adults with fear of heights. In experiments 1-4, exercise did not facilitate fear extinction, long-term memory, or fear relapse tests. In experiment 5, human participants showed an overall reduction in fear of heights but exercise did not enhance symptom improvement. Although acute exercise prior to fear extinction or exposure therapy, as operationalized in the present 5 studies, did not enhance outcomes, these results must be interpreted within the context of a broader literature that includes positive findings. Taken all together, this suggests that more research is necessary to identify optimal parameters and key individual differences so that exercise can be implemented successfully to treat anxiety disorders. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. D-cycloserine enhancement of exposure therapy for social anxiety disorder depends on the success of exposure sessions.

    Science.gov (United States)

    Smits, Jasper A J; Rosenfield, David; Otto, Michael W; Marques, Luana; Davis, Michelle L; Meuret, Alicia E; Simon, Naomi M; Pollack, Mark H; Hofmann, Stefan G

    2013-10-01

    The evidence for the efficacy of D-cycloserine (DCS) for augmenting cognitive behavioral therapy (CBT) for anxiety disorders has been mixed. Guided by preclinical research and initial findings from a small-scale study involving humans, we tested the hypothesis that DCS enhancement of exposure therapy would be specific to successful exposure sessions. Medication-free adults with generalized social anxiety disorder (N = 145) received 50 mg of DCS or placebo 1 h before each of 5 exposure sessions that were part of a standardized 12-session group CBT protocol. Participants provided fear ratings at the beginning and just before the end of exposure exercises. Independent raters, blind to group assignment, administered the clinical global impression improvement and severity scales at each session and at posttreatment. Mixed-effects analyses revealed that, among patients who reported low fear at the end of an exposure session, those who had received DCS evidenced significantly greater clinical improvement at the next session, relative to those who had received placebo. In contrast, when exposure end fear was high, patients receiving DCS exhibited less clinical improvement at the following session than patients receiving placebo. Similarly, patients who had received DCS evidenced lower clinical severity at posttreatment, relative to patients who had received placebo, only when their average end fear for medication-augmented sessions had been in the low to moderate range. Finally, these moderating effects of exposure success as indexed by end fear were not better accounted for by within-session extinction. The efficacy of DCS for augmenting exposure-based CBT depends on the success of exposure sessions. These findings may help guide the development of an algorithm for the effective use of DCS for augmenting exposure-based CBT. http://www.ClinicalTrials.gov, ID# NCT00633984, http://www.clinicaltrials.gov/ct2/show/NCT00633984. Copyright © 2013 Elsevier Ltd. All rights

  12. Delayed extinction and stronger drug-primed reinstatement of methamphetamine seeking in rats prenatally exposed to morphine.

    Science.gov (United States)

    Shen, Ying-Ling; Chen, Shao-Tsu; Chan, Tzu-Yi; Hung, Tsai-Wei; Tao, Pao-Luh; Liao, Ruey-Ming; Chan, Ming-Huan; Chen, Hwei-Hsien

    2016-02-01

    Prenatal morphine (PM) affects the development of brain reward system and cognitive function. The present study aimed to determine whether PM exposure increases the vulnerability to MA addiction. Pregnant Sprague-Dawley rats were administered saline or morphine during embryonic days 3-20. The acquisition, extinction and reinstatement of methamphetamine (MA) conditioned place preference (CPP) and intravenous self-administration (SA) paradigms were assessed in the male adult offspring. There was no difference in the acquisition and expression of MA CPP between saline- and PM-exposed rats, whereas PM-exposed rats exhibited slower extinction and greater MA priming-induced reinstatement of drug-seeking behavior than controls. Similarly, MA SA under progressive ratio and fixed ratio schedules was not affected by PM exposure, but PM-exposed rats required more extinction sessions to reach the extinction criteria and displayed more severe MA priming-, but not cue-induced, reinstatement. Such alterations in extinction and reinstatement were not present when PM-exposed rats were tested in an equivalent paradigm assessing operant responding for food pellets. Our results demonstrate that PM exposure did not affect the association memory formation during acquisition of MA CPP or SA, but impaired extinction learning and increased MA-primed reinstatement in both tasks. These findings suggest that the offspring of women using morphine or heroin during pregnancy might predict persistent MA seeking during extinction and enhanced propensity to MA relapse although they might not be more susceptible to the reinforcing effect of MA during initiation of drug use. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Human fear extinction and return of fear using reconsolidation update mechanisms: the contribution of on-line expectancy ratings.

    Science.gov (United States)

    Warren, Victor Taylor; Anderson, Kemp M; Kwon, Cliffe; Bosshardt, Lauren; Jovanovic, Tanja; Bradley, Bekh; Norrholm, Seth Davin

    2014-09-01

    Disruption of the reconsolidation of conditioned fear memories has been suggested as a non-pharmacological means of preventing the return of learned fear in human populations. A reconsolidation update paradigm was developed in which a reconsolidation window is opened by a single isolated retrieval trial of a previously reinforced CS+ which is then followed by Extinction Training within that window. However, follow-up studies in humans using multi-methods fear conditioning indices (e.g., fear-potentiated startle, skin conductance, US-expectancy) have failed to replicate the retrieval+extinction effects. In the present study, we further investigated the retrieval+extinction reconsolidation update paradigm by directly comparing the acquisition, extinction, and return of fear-potentiated startle in the absence or presence of US-expectancy measures (using a trial-by-trial response keypad) with and without retrieval of a previously acquired CS-US association. Participants were fear conditioned to two visual cue CS+'s, one of which was presented as a single, isolated retrieval trial before Extinction Training and one that was extinguished as usual. The results show that the inclusion of US-expectancy measures strengthens the CS-US association to provide enhanced fear conditioning and maintenance of fear memories over the experimental sessions. In addition, in the groups that used on-line US-expectancy measures, the retrieval+extinction procedure reduced reinstatement of fear-potentiated startle to both previously reinforced CS+'s, as compared to the extinction as usual group. Published by Elsevier Inc.

  14. Work session on the SAR. Pt. 2

    International Nuclear Information System (INIS)

    Burkart, K.

    1980-01-01

    The present paper contains the tables of the contribution of K. Burkart 'Work Session on the SAR' to the IAEA Interregional Training Course held in Sept/Oct. 1980 at the Kernforschungszentrum Karlsruhe. (RW)

  15. Session summary: Electronics, triggering and data acquisition

    International Nuclear Information System (INIS)

    Rescia, S.

    1991-12-01

    The session focused on the requirements for calorimetry at the SSC/LHC. Results on new readout techniques, calibration, radiation hard electronics and semiconductor devices, analog and digital front and electronics, and trigger strategies are presented

  16. Comparative analysis of pain in patients who underwent total knee replacement regarding the tourniquet pressure

    Directory of Open Access Journals (Sweden)

    Marcos George de Souza Leão

    Full Text Available ABSTRACT OBJECTIVES: To evaluate through the visual analog scale (VAS the pain in patients undergoing total knee replacement (TKR with different pressures of the pneumatic tourniquet. METHODS: An observational, randomized, descriptive study on an analytical basis, with 60 patients who underwent TKR, divided into two groups, which were matched: a group where TKR was performed with tourniquet pressures of 350 mmHg (standard and the other with systolic blood pressure plus 100 mmHg (P + 100. These patients had their pain assessed by VAS at 48 h, and at the 5th and 15th days after procedure. Secondarily, the following were also measured: range of motion (ROM, complications, and blood drainage volume in each group; the data were subjected to statistical analysis. RESULTS: After data analysis, there was no statistical difference regarding the incidence of complications (p = 0.612, ROM (p = 0.202, bleeding after 24 and 48 h (p = 0.432 and p = 0.254 or in relation to VAS. No correlation was observed between time of ischemia compared to VAS and bleeding. CONCLUSIONS: The use of the pneumatic tourniquet pressure at 350 mmHg or systolic blood pressure plus 100 mmHg did not influence the pain, blood loss, ROM, and complications. Therefore the pressures at these levels are safe and do not change the surgery outcomes; the time of ischemia must be closely observed to avoid major complications.

  17. Assessment of quality of life in patients who underwent minimally invasive cosmetic procedures.

    Science.gov (United States)

    de Aquino, Marcello Simão; Haddad, Alessandra; Ferreira, Lydia Masako

    2013-06-01

    There are increasingly more patients seeking minimally invasive procedures, which have become more effective and safer in reducing the signs of facial aging. This study included 40 female adult patients who voluntarily underwent selected minimally invasive procedures (filling with hyaluronic acid and botulinum toxin injection) for facial rejuvenation. All patients were followed for a period of 6 months. They were evaluated with the use of questionnaires, a quality-of-life questionnaire (DLQI), the self-esteem scale of Rosenberg (EPM/Rosenberg), and a pain scale. The minimally invasive procedures resulted in improvement in quality of life and self-esteem, which were stronger the first 3 months after the procedures but remained at a higher level than that before treatment, even after 6 months. Hyaluronic acid with lidocaine in the formula is more comfortable for the patient as it makes the injection less painful. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

  18. Assessment of Patients Who Underwent Nasal Reconstruction After Non-Melanoma Skin Cancer Excision.

    Science.gov (United States)

    Uzun, Hakan; Bitik, Ozan; Kamburoğlu, Haldun Onuralp; Dadaci, Mehmet; Çaliş, Mert; Öcal, Engin

    2015-06-01

    Basal and squamous cell carcinomas are the most common malignant cutaneous lesions affecting the nose. With the rising incidence of skin cancers, plastic surgeons increasingly face nasal reconstruction challenges. Although multiple options exist, optimal results are obtained when "like is used to repair like". We aimed to introduce a simple algorithm for the reconstruction of nasal defects with local flaps, realizing that there is always more than one option for reconstruction. We retrospectively reviewed 163 patients who underwent nasal reconstruction after excision of non-melanoma skin cancer between March 2011 and April 2014. We analyzed the location of the defects and correlated them with the techniques used to reconstruct them. There were 66 males and 97 females (age, 21-98 years). Basal cell carcinoma was diagnosed in 121 patients and squamous cell carcinoma in 42. After tumor excision, all the defects were immediately closed by either primary closure or local flap options such as Limberg, Miter, glabellar, bilobed, nasolabial, V-Y advancement, and forehead flaps. Obtaining tumor-free borders and a pleasing aesthetic result are major concerns in nasal reconstruction. Defect reconstruction and cosmesis are as important as rapid recovery and quick return to normal daily activities, and these should be considered before performing any procedure, particularly in elderly patients.

  19. [A survey of perioperative asthmatic attack among patients with bronchial asthma underwent general anesthesia].

    Science.gov (United States)

    Ie, Kenya; Yoshizawa, Atsuto; Hirano, Satoru; Izumi, Sinyuu; Hojo, Masaaki; Sugiyama, Haruhito; Kobayasi, Nobuyuki; Kudou, Kouichirou; Maehara, Yasuhiro; Kawachi, Masaharu; Miyakoshi, Kouichi

    2010-07-01

    We investigated the risk factor of perioperative asthmatic attack and effectiveness of preventing treatment for asthmatic attack before operation. We performed retrospective chart review of one hundred eleven patients with asthma underwent general anesthesia and surgical intervention from January 2006 to October 2007 in our hospital. The rate of perioperative asthmatic attack were as follows; 10.2% (5 in 49 cases) in no pretreatment group, 7.5% (3 in 40 cases) in any pretreatments except for systemic steroid, and 4.5% (1 in 22 cases) in systemic steroid pretreatment group. Neither preoperative asthma severity nor duration from the last attack had significant relevancy to perioperative attack rate. The otolaryngological surgery, especially those have nasal polyp and oral surgery had high perioperative asthma attack rate, although there was no significant difference. We recommend the systemic steroid pretreatment for asthmatic patients, especially when they have known risk factor such as administration of the systemic steroid within 6 months, or possibly new risk factor such as nasal polyp, otolaryngological and oral surgery.

  20. Influence of perioperative administration of amino acids on thermoregulation response in patients underwent colorectal surgical procedures

    Directory of Open Access Journals (Sweden)

    Zeba Snježana

    2007-01-01

    Full Text Available Background. Hypothermia in the surgical patients can be the consequence of long duration of surgical intervention, general anesthesia and low temperature in operating room. Postoperative hypothermia contributes to a number of postoperative complications such as arrhythmia, myocardial ischemia, hypertension, bleeding, wound infection, coagulopathy, prolonged effect of muscle relaxants. External heating procedures are used to prevent this condition, but some investigations reported that infusion of aminoacids during surgery can induce thermogenesis and prevent postoperative hypothermia. Case report. We reported two males who underwent major colorectal surgery for rectal carcinoma. One patient received Aminosol 15% solution, 125 ml/h, while the other did not. The esophageal temperatures in both cases were measured every 30 minutes during the operation and 60 minutes after in Intensive Care Unit. We were monitoring blood pressure, heart rate, ECG, and shivering. Patient who received aminoacids showed ameliorated postoperative hypothermia without hypertension, arrhythmia, or shivering, while the other showed all symptoms mentioned above. Conclusion. According to literature data, as well as our findings, we can conclude that intraoperative intravenous treatment with amino acid solution ameliorates postoperative hypothermia along with its complications. .

  1. Congenital hydrocele: prevalence and outcome among male children who underwent neonatal circumcision in Benin City, Nigeria.

    Science.gov (United States)

    Osifo, O D; Osaigbovo, E O

    2008-06-01

    To determine the prevalence and spontaneous resolution of congenital hydrocele diagnosed in male neonates who underwent circumcision at our centre. All male neonates presented for circumcision at the University of Benin Teaching Hospital, Benin City, Nigeria between January 2002 and December 2006 were examined for the presence of hydrocele. Those diagnosed with this condition were recruited and followed up in a surgical outpatient clinic for 2 years. The number of cases of spontaneous resolution and age at which this occurred were documented on a structured pro forma. A total of 2715 neonates were circumcised and 128 (4.7%) were diagnosed with 163 cases of hydrocele, while 27 cases in 25 (0.9%) children failed to resolve at the age of 2 years. Neonatal hydrocele was bilateral in 112 (68.7%), and there were 20 (12.3%) right and 31 (19.0%) left. Among those with hydrocele, 28.1% were delivered preterm and resolution was spontaneous in many of them, with no observed significant statistical difference to those delivered full term (P=0.4740). Of the 163 hydrocele cases, 136 (83.4%) resolved spontaneously by age 18 months with peak resolution at 4-6 months. No spontaneous resolution occurred after 18 months and no hydrocele-related complication occurred during follow up. Neonates with congenital hydrocele should be observed for spontaneous resolution for at least 18 months before being subjected to surgery.

  2. Stress and Quality of Life for Taiwanese Women Who Underwent Infertility Treatment.

    Science.gov (United States)

    Cheng, Ching-Yu; Stevenson, Eleanor Lowndes; Yang, Cheng-Ta; Liou, Shwu-Ru

    2018-04-28

    To describe the psychological stress and quality of life experienced by women who underwent fertility treatment in Taiwan. Cross-sectional, correlational study. Recruitment was conducted and questionnaires administered at a reproductive medicine center in Chiayi City, Taiwan. Informed consent to participate was obtained from 126 women who sought fertility treatment at the center. The Chinese Fertility Problem Inventory and Fertility Quality of Life scale were used to measure participants' levels of fertility-related stress and fertility-related quality of life. Descriptive statistics, correlation, and regression analysis were used. Overall, participants reported low levels of fertility-related stress and fertility-related quality of life; however, they had relatively high levels of stress related to need for parenthood. Women who were older, had greater body mass indexes, and consumed coffee regularly had lower fertility-related quality of life. Social and relationship concerns and stress related to need for parenthood were significant predictors of low fertility-related quality of life. In a culture in which childbearing is generally an expectation and an important part of family life, women who experience infertility are at risk to experience fertility-related stress. Social support and family consultation might be offered to improve women's fertility-related quality of life. Copyright © 2018 AWHONN, the Association of Women’s Health, Obstetric and Neonatal Nurses. Published by Elsevier Inc. All rights reserved.

  3. The Effectiveness of Adjuvant Hyperbaric Oxygen Therapy in Adults who Underwent Hypospadias Surgery

    Directory of Open Access Journals (Sweden)

    Onder Kara

    2017-01-01

    Full Text Available Aim: To evaluate the role of hyperbaric oxygen therapy (HBO2T with buccal mucosal tube urethroplasty in adult patients with hypospadias. Material and Method: Sixteen adult patients with hypospadias were included in our study. Patients with a short urethra and penile curvature were treated in two stages (orthoplasty buccal mucosal tube urethroplasty. Buccal mucosa was taken and prepared for tube urethroplasty around a 16 French (Fr nelaton catheter and the urethral tube was introduced between the urethral meatus and glans penis. Beginning the 1st postoperative day (HBO2T was applied for 10 sessions during weekdays in 13 patients. Results: The mean age was 21 (±1.23 years and mean follow-up time was 10.1 (±2.1 months. In the group who received HBO2T postoperatively (n=13, a two-stage (orthoplasty buccal mucosal tube urethroplasty procedure was performed in 6 (46%, and the mean length of graft was 5.4 (±1.23 cm. In this group of 13 the success rate without any additional manipulations (urethrotomy intern, fistula repair was 54% (7/13. After additional manipulations, complete healing was achieved in 11 out of 13 patients (84.6%. In the group who did not receive HBO2T postoperatively (n=3, a two-stage procedure was performed in 1 patient (33%, and the mean length of graft was 8 (±5 cm. In this group of 3, complete healing was not achieved in any of these patients as a result of the hypospadias surgery. However, after the additional manipulations, complete healing was achieved in 1 patient (33%. Discussion: Given the promising rates of surgical success, postoperative HBO2T might be considered as a supportive treatment modality for adult patients with hypospadias who undergo buccal mucosal tube urethroplasty. Randomized controlled studies are needed.

  4. Summary of the relativistic heavy ion sessions

    International Nuclear Information System (INIS)

    Harris, J.W.

    1988-01-01

    The topics covered in the Relativistic Heavy Ion Sessions span four orders of magnitude in energy in the laboratory and a few more in theory. In the two years since the last Intersections conference, experiments in the field of very high energy heavy ion research have begun at CERN and Brookhaven. The prime motivation for these experiments is the possibility of forming quark matter. This paper is a review of the topics covered in the Relativistic Heavy Ion Sessions

  5. Lymphocyte Redox Imbalance and Reduced Proliferation after a Single Session of High Intensity Interval Exercise.

    Science.gov (United States)

    Tossige-Gomes, Rosalina; Costa, Karine Beatriz; Ottone, Vinícius de Oliveira; Magalhães, Flávio de Castro; Amorim, Fabiano Trigueiro; Rocha-Vieira, Etel

    2016-01-01

    This study investigated whether an acute session of high-intensity interval training (HIIT) is sufficient to alter lymphocyte function and redox status. Sixteen young healthy men underwent a HIIT session on a cycloergometer, consisting of eight bouts of 1 min at 90-100% of peak power, with 75 seconds of active recovery at 30 W between bouts. Venous blood was collected before, immediately after, and 30 minutes after the HIIT session. In response to Staphylococcus aureus superantigen B (SEB) stimulation, lymphocyte proliferation decreased and the IL-2 concentration increased after the HIIT session. However, the HIIT session had no effect on lymphocyte proliferation or IL-2 response to phytohemagglutinin stimulation. The HIIT session also induced lymphocyte redox imbalance, characterized by an increase in the concentration of thiobarbituric acid reactive substances and a decrease in the activity of the antioxidant enzyme catalase. Lymphocyte viability was not affected by the HIIT session. The frequencies of CD25+ and CD69+ T helper and B lymphocytes in response to superantigen stimulation were lower after exercise, suggesting that superantigen-induced lymphocyte activation was reduced by HIIT. However, HIIT also led to a reduction in the frequency of CD4+ and CD19+ cells, so the frequencies of CD25+ and CD69+ cells within the CD4 and CD19 cell populations were not affected by HIIT. These data indicate that the reduced lymphocyte proliferation observed after HIIT is not due to reduced early lymphocyte activation by superantigen. Our findings show that an acute HIIT session promotes lymphocyte redox imbalance and reduces lymphocyte proliferation in response to superantigenic, but not to mitogenic stimulation. This observation cannot be explained by alteration of the early lymphocyte activation response to superantigen. The manner in which lymphocyte function modulation by an acute HIIT session can affect individual immunity and susceptibility to infection is important

  6. Lymphocyte Redox Imbalance and Reduced Proliferation after a Single Session of High Intensity Interval Exercise.

    Directory of Open Access Journals (Sweden)

    Rosalina Tossige-Gomes

    Full Text Available This study investigated whether an acute session of high-intensity interval training (HIIT is sufficient to alter lymphocyte function and redox status. Sixteen young healthy men underwent a HIIT session on a cycloergometer, consisting of eight bouts of 1 min at 90-100% of peak power, with 75 seconds of active recovery at 30 W between bouts. Venous blood was collected before, immediately after, and 30 minutes after the HIIT session. In response to Staphylococcus aureus superantigen B (SEB stimulation, lymphocyte proliferation decreased and the IL-2 concentration increased after the HIIT session. However, the HIIT session had no effect on lymphocyte proliferation or IL-2 response to phytohemagglutinin stimulation. The HIIT session also induced lymphocyte redox imbalance, characterized by an increase in the concentration of thiobarbituric acid reactive substances and a decrease in the activity of the antioxidant enzyme catalase. Lymphocyte viability was not affected by the HIIT session. The frequencies of CD25+ and CD69+ T helper and B lymphocytes in response to superantigen stimulation were lower after exercise, suggesting that superantigen-induced lymphocyte activation was reduced by HIIT. However, HIIT also led to a reduction in the frequency of CD4+ and CD19+ cells, so the frequencies of CD25+ and CD69+ cells within the CD4 and CD19 cell populations were not affected by HIIT. These data indicate that the reduced lymphocyte proliferation observed after HIIT is not due to reduced early lymphocyte activation by superantigen. Our findings show that an acute HIIT session promotes lymphocyte redox imbalance and reduces lymphocyte proliferation in response to superantigenic, but not to mitogenic stimulation. This observation cannot be explained by alteration of the early lymphocyte activation response to superantigen. The manner in which lymphocyte function modulation by an acute HIIT session can affect individual immunity and susceptibility to

  7. Prefrontal Cortex KCa2 Channels Regulate mGlu5-Dependent Plasticity and Extinction of Alcohol-Seeking Behavior.

    Science.gov (United States)

    Cannady, Reginald; McGonigal, Justin T; Newsom, Ryan J; Woodward, John J; Mulholland, Patrick J; Gass, Justin T

    2017-04-19

    Identifying novel treatments that facilitate extinction learning could enhance cue-exposure therapy and reduce high relapse rates in alcoholics. Activation of mGlu 5 receptors in the infralimbic prefrontal cortex (IL-PFC) facilitates learning during extinction of cue-conditioned alcohol-seeking behavior. Small-conductance calcium-activated potassium (K Ca 2) channels have also been implicated in extinction learning of fear memories, and mGlu 5 receptor activation can reduce K Ca 2 channel function. Using a combination of electrophysiological, pharmacological, and behavioral approaches, this study examined K Ca 2 channels as a novel target to facilitate extinction of alcohol-seeking behavior in rats. This study also explored related neuronal and synaptic mechanisms within the IL-PFC that underlie mGlu 5 -dependent enhancement of extinction learning. Using whole-cell patch-clamp electrophysiology, activation of mGlu 5 in ex vivo slices significantly reduced K Ca 2 channel currents in layer V IL-PFC pyramidal neurons, confirming functional downregulation of K Ca 2 channel activity by mGlu 5 receptors. Additionally, positive modulation of K Ca 2 channels prevented mGlu 5 receptor-dependent facilitation of long-term potentiation in the IL-PFC. Systemic and intra-IL-PFC treatment with apamin (K Ca 2 channel allosteric inhibitor) significantly enhanced extinction of alcohol-seeking behavior across multiple extinction sessions, an effect that persisted for 3 weeks, but was not observed after apamin microinfusions into the prelimbic PFC. Positive modulation of IL-PFC K Ca 2 channels significantly attenuated mGlu 5 -dependent facilitation of alcohol cue-conditioned extinction learning. These data suggest that mGlu 5 -dependent facilitation of extinction learning and synaptic plasticity in the IL-PFC involves functional inhibition of K Ca 2 channels. Moreover, these findings demonstrate that K Ca 2 channels are a novel target to facilitate long-lasting extinction of alcohol

  8. Climate change. Accelerating extinction risk from climate change.

    Science.gov (United States)

    Urban, Mark C

    2015-05-01

    Current predictions of extinction risks from climate change vary widely depending on the specific assumptions and geographic and taxonomic focus of each study. I synthesized published studies in order to estimate a global mean extinction rate and determine which factors contribute the greatest uncertainty to climate change-induced extinction risks. Results suggest that extinction risks will accelerate with future global temperatures, threatening up to one in six species under current policies. Extinction risks were highest in South America, Australia, and New Zealand, and risks did not vary by taxonomic group. Realistic assumptions about extinction debt and dispersal capacity substantially increased extinction risks. We urgently need to adopt strategies that limit further climate change if we are to avoid an acceleration of global extinctions. Copyright © 2015, American Association for the Advancement of Science.

  9. Parasacral transcutaneous electrical stimulation for overactive bladder in children: An assessment per session.

    Science.gov (United States)

    Veiga, Maria Luiza; Queiroz, Ana Paula; Carvalho, Maria Clara; Braga, Ana Aparecida Nascimento Martineli; Sousa, Ariane Sampaio; Barroso, Ubirajara

    2016-10-01

    Neuromodulation has emerged as an effective therapeutic option for treatment of OAB in children. However, to our knowledge, no study has yet evaluated the results of neuromodulation on a session-by-session basis. The aim of this study was to evaluate the rate of complete response of overactive bladder (OAB) symptoms for each session of transcutaneous electrical stimulation (TENS), in a protocol of 20 sessions of therapy. This is a prospective study of the improvement of LUTS in children with isolated OAB. Included in this study were children over the age of 4 years who complained of urinary urgency, had bell-or tower-shaped uroflowmetry patterns, and post-void residual urinary tract symptoms (LUTS) secondary to urinary tract abnormalities. All patients underwent parasacral transcutaneous neurostimulation (TENS). The development of symptoms was observed right before each session using a visual analog scale (VAS) in which 0 means the absence of improvement and 10 represents maximum improvement of symptoms. We noted a complete resolution of symptoms (urgency, urge incontinence, frequency, and holding maneuvers) in some patients starting after the third session. In the 10th and 20th (last) sessions, 12 (17.4%) and 38 (55.1%) patients reported a complete resolution of symptoms. After complete resolution, 12 (17.4%) patients reported that their symptoms worsened to a minimum level of 40% improvement, but this was temporary and all returned to 100% improvement. Children who showed an improvement level greater than 50% in the fifth treatment session were 4.18 (p = 0.007) times more likely to have success in the last treatment session. We found that a patient can experience complete symptom resolution as quickly as following the third session of TENS. The complete response rate progressively increases with the number of sessions, slowly until the 12th session and more rapidly after that. When symptom improvement of at least 50% is reported in the fifth session, there is a

  10. Switching between phenotypes and population extinction

    Science.gov (United States)

    Lohmar, Ingo; Meerson, Baruch

    2011-11-01

    Many types of bacteria can survive under stress by switching stochastically between two different phenotypes: the “normals” who multiply fast, but are vulnerable to stress, and the “persisters” who hardly multiply, but are resilient to stress. Previous theoretical studies of such bacterial populations have focused on the fitness: the asymptotic rate of unbounded growth of the population. Yet for an isolated population of established (and not very large) size, a more relevant measure may be the population extinction risk due to the interplay of adverse extrinsic variations and intrinsic noise of birth, death and switching processes. Applying a WKB approximation to the pertinent master equation of such a two-population system, we quantify the extinction risk, and find the most likely path to extinction under both favorable and adverse conditions. Analytical results are obtained both in the biologically relevant regime when the switching is rare compared with the birth and death processes, and in the opposite regime of frequent switching. We show that rare switches are most beneficial in reducing the extinction risk.

  11. Extinction and renewal of conditioned sexual responses

    NARCIS (Netherlands)

    Brom, Mirte; Laan, Ellen; Everaerd, Walter; Spinhoven, Philip; Both, Stephanie

    2014-01-01

    Extinction involves an inhibitory form of new learning that is highly dependent on the context for expression. This is supported by phenomena such as renewal and spontaneous recovery, which may help explain the persistence of appetitive behavior, and related problems such as addictions. Research on

  12. Extinction and renewal of conditioned sexual responses

    NARCIS (Netherlands)

    Brom, M.; Laan, E.; Everaerd, W.; Spinhoven, P.; Both, S.

    2014-01-01

    INTRODUCTION: Extinction involves an inhibitory form of new learning that is highly dependent on the context for expression. This is supported by phenomena such as renewal and spontaneous recovery, which may help explain the persistence of appetitive behavior, and related problems such as

  13. Extinction and renewal of conditioned sexual responses.

    Directory of Open Access Journals (Sweden)

    Mirte Brom

    Full Text Available INTRODUCTION: Extinction involves an inhibitory form of new learning that is highly dependent on the context for expression. This is supported by phenomena such as renewal and spontaneous recovery, which may help explain the persistence of appetitive behavior, and related problems such as addictions. Research on these phenomena in the sexual domain is lacking, where it may help to explain the persistence of learned sexual responses. METHOD: Men (n = 40 and women (n = 62 participated in a differential conditioning paradigm, with genital vibrotactile stimulation as US and neutral pictures as conditional stimuli (CSs. Dependent variables were genital and subjective sexual arousal, affect, US expectancy, and approach and avoid tendencies towards the CSs. Extinction and renewal of conditioned sexual responses were studied by context manipulation (AAA vs. ABA condition. RESULTS: No renewal effect of genital conditioned responding could be detected, but an obvious recovery of US expectancy following a context change after extinction (ABA was demonstrated. Additionally, women demonstrated recovery of subjective affect and subjective sexual arousal. Participants in the ABA demonstrated more approach biases towards stimuli. CONCLUSIONS: The findings support the context dependency of extinction and renewal of conditioned sexual responses in humans. This knowledge may have implications for the treatment of disturbances in sexual appetitive responses such as hypo- and hypersexuality.

  14. Methylphenidate Enhances Extinction of Contextual Fear

    Science.gov (United States)

    Abraham, Antony D.; Cunningham, Christopher L.; Lattal, K. Matthew

    2012-01-01

    Methylphenidate (MPH, Ritalin) is a norepinephrine and dopamine transporter blocker that is widely used in humans for treatment of attention deficit disorder and narcolepsy. Although there is some evidence that targeted microinjections of MPH may enhance fear acquisition, little is known about the effect of MPH on fear extinction. Here, we show…

  15. ULTRAVIOLET EXTINCTION AT HIGH GALACTIC LATITUDES

    Energy Technology Data Exchange (ETDEWEB)

    Peek, J. E. G.; Schiminovich, David, E-mail: jegpeek@gmail.com [Department of Astronomy, Columbia University, New York, NY (United States)

    2013-07-01

    In order to study the properties and effects of high Galactic latitude dust, we present an analysis of 373,303 galaxies selected from the Galaxy Evolution Explorer All-Sky Survey and Wide-field Infrared Explorer All-Sky Data Release. By examining the variation in aggregate ultraviolet colors and number density of these galaxies, we measure the extinction curve at high latitude. We additionally consider a population of spectroscopically selected galaxies from the Sloan Digital Sky Survey to measure extinction in the optical. We find that dust at high latitude is neither quantitatively nor qualitatively consistent with standard reddening laws. Extinction in the FUV and NUV is {approx}10% and {approx}35% higher than expected, with significant variation across the sky. We find that no single R{sub V} parameter fits both the optical and ultraviolet extinction at high latitude, and that while both show detectable variation across the sky, these variations are not related. We propose that the overall trends we detect likely stem from an increase in very small silicate grains in the interstellar medium.

  16. The Neandertal extinction in eastern Central Europe

    Czech Academy of Sciences Publication Activity Database

    Svoboda, Jiří

    2005-01-01

    Roč. 137, - (2005), s. 69-75 ISSN 1040-6182 Institutional research plan: CEZ:AV0Z80010507 Keywords : Central Europe Neandertals * early modern humans * extinction Subject RIV: AC - Archeology, Anthropology, Ethnology Impact factor: 1.210, year: 2005

  17. ULTRAVIOLET EXTINCTION AT HIGH GALACTIC LATITUDES

    International Nuclear Information System (INIS)

    Peek, J. E. G.; Schiminovich, David

    2013-01-01

    In order to study the properties and effects of high Galactic latitude dust, we present an analysis of 373,303 galaxies selected from the Galaxy Evolution Explorer All-Sky Survey and Wide-field Infrared Explorer All-Sky Data Release. By examining the variation in aggregate ultraviolet colors and number density of these galaxies, we measure the extinction curve at high latitude. We additionally consider a population of spectroscopically selected galaxies from the Sloan Digital Sky Survey to measure extinction in the optical. We find that dust at high latitude is neither quantitatively nor qualitatively consistent with standard reddening laws. Extinction in the FUV and NUV is ∼10% and ∼35% higher than expected, with significant variation across the sky. We find that no single R V parameter fits both the optical and ultraviolet extinction at high latitude, and that while both show detectable variation across the sky, these variations are not related. We propose that the overall trends we detect likely stem from an increase in very small silicate grains in the interstellar medium.

  18. Molar extinction coefficients of some fatty acids

    DEFF Research Database (Denmark)

    Sandhu, G.K.; Singh, K.; Lark, B.S.

    2002-01-01

    ) and stearic acid (C18H36O2), has been measured at the photon energies 81, 356, 511, 662, 1173 and 1332 keV. Experimental values for the molar extinction coefficient, the effective atomic number and the electron density have been derived and compared with theoretical calculations. There is good agreement...

  19. Evolution of Dust Extinction and Supernova Cosmology.

    Science.gov (United States)

    Totani; Kobayashi

    1999-12-01

    We have made a quantitative calculation for the systematic evolution of the average extinction by interstellar dust in host galaxies of high-redshift Type Ia supernovae by using a realistic model of photometric and chemical evolution of galaxies and supernova rate histories in various galaxy types. We find that the average B-band extinction at z approximately 0.5 is typically 0.1-0.2 mag larger than the present value, under a natural assumption that dust optical depth is proportional to gas column density and gas metallicity. This systematic evolution causes average reddening with E(B-V&parr0; approximately 0.025-0.05 mag with the standard extinction curve, and this is comparable with the observational uncertainty of the reddening of high-redshift supernovae. Therefore, our result does not contradict the observations that show no significant reddening in high-z supernovae. However, the difference in apparent magnitude between an open universe and a Lambda-dominated flat universe is only approximately 0.2 mag at z approximately 0.5, and hence this systematic evolution of extinction should be taken into account in a reliable measurement of cosmological parameters. Considering this uncertainty, we show that it is difficult to discriminate between open and Lambda-dominated flat cosmologies from the current data.

  20. Optical atmospheric extinction over Cerro Paranal

    NARCIS (Netherlands)

    Patat, F.; Moehler, S.; O'Brien, K.; Pompei, E.; Bensby, T.; Carraro, G.; de Ugarte Postigo, A.; Fox, A.; Gavignaud, I.; James, G.; Korhonen, H.; Ledoux, C.; Randall, S.; Sana, H.A.A.; Smoker, J.; Stefl, S.; Szeifert, T.

    2011-01-01

    Aims. The present study was conducted to determine the optical extinction curve for Cerro Paranal under typical clear-sky observing conditions, with the purpose of providing the community with a function to be used to correct the observed spectra, with an accuracy of 0.01 mag airmass-1.

  1. Protostars at Low Extinction in Orion A

    Science.gov (United States)

    Lewis, John Arban; Lada, Charles J.

    2016-07-01

    In the list of young stellar objects (YSOs) compiled by Megeath et al. for the Orion A molecular cloud, only 44 out of 1208 sources found projected onto low extinction ({A}{{K}}\\lt 0.8 mag) gas are identified as protostars. These objects are puzzling because protostars are not typically expected to be associated with extended low extinction material. Here, we use high resolution extinction maps generated from Herschel data, optical/infrared and Spitzer Space Telescope photometry and spectroscopy of the low extinction protostellar candidate sources to determine if they are likely true protostellar sources or contaminants. Out of 44 candidate objects, we determine that 10 sources are likely protostars, with the rest being more evolved YSOs (18), galaxies (4), false detections of nebulosity and cloud edges (9), or real sources for which more data are required to ascertain their nature (3). We find none of the confirmed protostars to be associated with recognizable dense cores and we briefly discuss possible origins for these orphaned objects.

  2. Time to extinction of bird populations

    NARCIS (Netherlands)

    Sæther, B-E.; Engen, S.; Møller, A.P.; Visser, M.E.; Matthysen, E.; Fiedler, W.; Lambrechts, M.M.; Becker, P.H.; Brommer, J.E.; Dickinson, J.; du Feu, C.; Gehlbach, F.R.; Merilä, J.; Rendell, W.; Robertson, R.J.; Thomson, D.L.; Török, J.

    2005-01-01

    The risk of extinction of populations has not previously been empirically related to parameters characterizing their population dynamics. To analyze this relationship, we simulated how the distribution of population dynamical characters changed as a function of time, in both the remaining and the

  3. Hibernation and daily torpor minimize mammalian extinctions

    Science.gov (United States)

    Geiser, Fritz; Turbill, Christopher

    2009-10-01

    Small mammals appear to be less vulnerable to extinction than large species, but the underlying reasons are poorly understood. Here, we provide evidence that almost all (93.5%) of 61 recently extinct mammal species were homeothermic, maintaining a constant high body temperature and thus energy expenditure, which demands a high intake of food, long foraging times, and thus exposure to predators. In contrast, only 6.5% of extinct mammals were likely heterothermic and employed multi-day torpor (hibernation) or daily torpor, even though torpor is widespread within more than half of all mammalian orders. Torpor is characterized by substantial reductions of body temperature and energy expenditure and enhances survival during adverse conditions by minimizing food and water requirements, and consequently reduces foraging requirements and exposure to predators. Moreover, because life span is generally longer in heterothermic mammals than in related homeotherms, heterotherms can employ a ‘sit-and-wait’ strategy to withstand adverse periods and then repopulate when circumstances improve. Thus, torpor is a crucial but hitherto unappreciated attribute of small mammals for avoiding extinction. Many opportunistic heterothermic species, because of their plastic energetic requirements, may also stand a better chance of future survival than homeothermic species in the face of greater climatic extremes and changes in environmental conditions caused by global warming.

  4. Dust extinction in the first galaxies

    Science.gov (United States)

    Jaacks, Jason; Finkelstein, Steven L.; Bromm, Volker

    2018-04-01

    Using cosmological volume simulations and a custom built sub-grid model for Population III (Pop III) star formation, we examine the baseline dust extinction in the first galaxies due to Pop III metal enrichment in the first billion years of cosmic history. We find that although the most enriched, high-density lines of sight in primordial galaxies can experience a measurable amount of extinction from Pop III dust [E(B - V)max = 0.07, AV, max ≈ 0.28], the average extinction is very low with ≲ 10-3. We derive a power-law relationship between dark matter halo mass and extinction of E(B-V)∝ M_halo^{0.80}. Performing a Monte Carlo parameter study, we establish the baseline reddening of the ultraviolet spectra of dwarf galaxies at high redshift due to Pop III enrichment only. With this method, we find - 2.51 ± 0.07, which is both nearly halo mass and redshift independent.

  5. Biological hierarchies and the nature of extinction.

    Science.gov (United States)

    Congreve, Curtis R; Falk, Amanda R; Lamsdell, James C

    2018-05-01

    Hierarchy theory recognises that ecological and evolutionary units occur in a nested and interconnected hierarchical system, with cascading effects occurring between hierarchical levels. Different biological disciplines have routinely come into conflict over the primacy of different forcing mechanisms behind evolutionary and ecological change. These disconnects arise partly from differences in perspective (with some researchers favouring ecological forcing mechanisms while others favour developmental/historical mechanisms), as well as differences in the temporal framework in which workers operate. In particular, long-term palaeontological data often show that large-scale (macro) patterns of evolution are predominantly dictated by shifts in the abiotic environment, while short-term (micro) modern biological studies stress the importance of biotic interactions. We propose that thinking about ecological and evolutionary interactions in a hierarchical framework is a fruitful way to resolve these conflicts. Hierarchy theory suggests that changes occurring at lower hierarchical levels can have unexpected, complex effects at higher scales due to emergent interactions between simple systems. In this way, patterns occurring on short- and long-term time scales are equally valid, as changes that are driven from lower levels will manifest in different forms at higher levels. We propose that the dual hierarchy framework fits well with our current understanding of evolutionary and ecological theory. Furthermore, we describe how this framework can be used to understand major extinction events better. Multi-generational attritional loss of reproductive fitness (MALF) has recently been proposed as the primary mechanism behind extinction events, whereby extinction is explainable solely through processes that result in extirpation of populations through a shutdown of reproduction. While not necessarily explicit, the push to explain extinction through solely population-level dynamics

  6. Long-term outcomes of four patients with tracheal agenesis who underwent airway and esophageal reconstruction.

    Science.gov (United States)

    Tazuke, Yuko; Okuyama, Hiroomi; Uehara, Shuichiro; Ueno, Takehisa; Nara, Keigo; Yamanaka, Hiroaki; Kawahara, Hisayoshi; Kubota, Akio; Usui, Noriaki; Soh, Hideki; Nomura, Motonari; Oue, Takaharu; Sasaki, Takashi; Nose, Satoko; Saka, Ryuta

    2015-12-01

    The aim of this study was to evaluate the long-term outcomes of four patients with tracheal agenesis who underwent airway and esophageal/alimentary reconstruction. We reviewed the medical records of four long-term survivors of tracheal agenesis and collected the following data: age, sex, type of tracheal agenesis, method of reconstruction, nutritional management, and physical and neurological development. The patients consisted of three boys and one girl, who ranged in age from 77 to 109months. The severity of their condition was classified as Floyd's type I (n=2), II (n=1), or III (n=1). Mechanical respiratory support was not necessary in any of the cases. Esophageal/alimentary reconstruction was performed using the small intestine (n=2), a gastric tube (n=1), and the esophagus (n=1). The age at esophageal reconstruction ranged from 41 to 55months. All of the cases required enteral nutrition via gastrostomy. Three of the patients were able to swallow a small amount of liquid and one was able to take pureed food orally. The physical development of the subjects was moderately delayed-borderline in childhood. Neurological development was normal in two cases and slightly delayed in two cases. None of the long-term survivors of tracheal agenesis required the use of an artificial respirator, and their development was close to normal. Future studies should aim to elucidate the optimal method for performing esophageal reconstruction to allow tracheal agenesis patients to achieve their full oral intake. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Predictors of weight regain in patients who underwent Roux-en-Y gastric bypass surgery.

    Science.gov (United States)

    Shantavasinkul, Prapimporn Chattranukulchai; Omotosho, Philip; Corsino, Leonor; Portenier, Dana; Torquati, Alfonso

    2016-11-01

    Roux-en-Y gastric bypass (RYGB) is a highly effective treatment for obesity and results in long-term weight loss and resolution of co-morbidities. However, weight regain may occur as soon as 1-2 years after surgery. This retrospective study aimed to investigate the prevalence of weight regain and possible preoperative predictors of this phenomenon after RYGB. An academic medical center in the United States. A total of 1426 obese patients (15.8% male) who underwent RYGB during January 2000 to 2012 and had at least a 2-year follow-up were reviewed. We included only patients who were initially successful, having achieved at least 50% excess weight loss at 1 year postoperatively. Patients were then categorized into either the weight regain group (WR) or sustained weight loss (SWL) group based upon whether they gained≥15% of their 1-year postoperative weight. Weight regain was observed in 244 patients (17.1%). Preoperative body mass index was similar between groups. Body mass index was significantly higher and percent excess weight loss was significantly lower in the WR group (Pweight regain was 19.5±9.3 kg and-.8±8.5 in the WR and SWL groups, respectively (Pweight loss. Moreover, a longer duration after RYGB was associated with weight regain. Multivariate analysis revealed that younger age was a significant predictor of weight regain even after adjusting for time since RYGB. The present study confirmed that a longer interval after RYGB was associated with weight regain. Younger age was a significant predictor of weight regain even after adjusting for time since RYGB. The findings of this study underscore the complexity of the mechanisms underlying weight loss and regain after RYGB. Future prospective studies are needed to further explore the prevalence, predictors, and mechanisms of weight regain after RYGB. Copyright © 2016 American Society for Bariatric Surgery. Published by Elsevier Inc. All rights reserved.

  8. Evaluation of patients who underwent resympathectomy for treatment of primary hyperhidrosis.

    Science.gov (United States)

    de Campos, José Ribas Milanez; Lembrança, Lucas; Fukuda, Juliana Maria; Kauffman, Paulo; Teivelis, Marcelo Passos; Puech-Leão, Pedro; Wolosker, Nelson

    2017-11-01

    Video thoracoscopic sympathectomy is the recommended surgical treatment for primary hyperhidrosis and has a high success rate. Despite this high success rate, some patients are unresponsive and eventually need a resympathectomy. Few studies have previously analysed exclusively the results of these resympathectomies in patients with primary hyperhidrosis. None of the studies have objectively evaluated the degree of response to surgery or the improvement in quality of life after resympathectomies. This is a retrospective study, evaluating 15 patients from an initial group of 2300 patients who underwent resympathectomy after failure of the primary surgical treatment. We evaluated sympathectomy levels of resection, technical difficulties, surgical complications preoperative quality of life, response to treatment and quality-of-life improvement 30 days after each surgery. Regarding gender, 11 (73.3%) patients were women. The average age was 23.2 with SD of 5.17 years, and the mean body mass index was 20.9 (SD 2.12). Ten patients had major complaints about their hands (66%) and 5 (33%) patients about their forearms. A high degree of response to sympathectomy occurred in 73% of patients. In 11 of these patients, the improvement in quality of life was considered high, 3 showed a mild improvement and 1 did not improve. No major complications occurred; the presence of adhesions was reported in 11 patients and pleural drainage was necessary in 4 patients. Resympathectomy is an effective procedure, and it improves the quality of life in patients with primary hyperhidrosis who failed after the first surgery. © The Author 2017. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  9. Surgical outcomes of 380 patients with double outlet right ventricle who underwent biventricular repair.

    Science.gov (United States)

    Li, Shoujun; Ma, Kai; Hu, Shengshou; Hua, Zhongdong; Yang, Keming; Yan, Jun; Chen, Qiuming

    2014-09-01

    The study objective was to report the outcomes of biventricular repair in patients with double outlet right ventricle. Patients with double outlet right ventricle who underwent biventricular repair at Fuwai Hospital from January 2005 to December 2012 were included. Patients were excluded if double outlet right ventricle was combined with atrioventricular septal defect, heterotaxy syndrome, atrioventricular discordance, or univentricular physiology. A total of 380 consecutive patients with a mean age of 1.9 ± 2.1 years (range, 1 month to 6 years) were included. Varied types of biventricular repair were customized individually. Follow-up was 90.4% complete, and the mean follow-up time was 3.4 ± 3.9 years. There were 17 (4.5%) early deaths and 7 (2.1%) late deaths. Preoperative pulmonary hypertension was the only risk factor for early mortality. Postoperative significant left ventricular outflow tract obstruction was present in 9 survivors. Patients with noncommitted ventricular septal defect had a longer crossclamp time, longer cardiopulmonary bypass time, and higher incidence of postdischarge left ventricular outflow tract obstruction. There were 4 reoperations, all of which were caused by subaortic left ventricular outflow tract obstruction. All of the pressure gradients were decreased to less than 20 mm Hg after the modified Konno procedure with an uneventful postoperative course. Optimal results of varied types of biventricular repair for double outlet right ventricle have been acquired. Although noncommitted ventricular septal defect is technically difficult, the outcomes of patients are favorable. Late-onset left ventricular outflow tract obstruction is the main reason for reoperation but can be successfully relieved by the modified Konno procedure. Copyright © 2014 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

  10. Newly Developed Sarcopenia as a Prognostic Factor for Survival in Patients who Underwent Liver Transplantation.

    Directory of Open Access Journals (Sweden)

    Ja Young Jeon

    Full Text Available The relationship between a perioperative change in sarcopenic status and clinical outcome of liver transplantation (LT is unknown. We investigated whether post-LT sarcopenia and changes in sarcopenic status were associated with the survival of patients.This retrospective study was based on a cohort of 145 patients from a single transplant center who during a mean of 1 year after LT underwent computed tomography imaging evaluation. The cross-sectional area of the psoas muscle of LT patients was compared with that of age- and sex-matched healthy individuals. The Cox proportional hazards regression model was used to determine whether post-LT sarcopenia and changes in sarcopenic status affect post-LT survival.The mean age at LT of the 116 male and 29 female patients was 50.2 ± 7.9 years; the mean follow-up duration was 51.6 ± 32.9 months. All pre-LT patients with sarcopenia still had sarcopenia 1 year after LT; 14 (15% patients had newly developed sarcopenia. The mean survival duration was 91.8 ± 4.2 months for non-sarcopenic patients and 80.0 ± 5.2 months for sarcopenic patients (log-rank test, p = 0.069. In subgroup analysis, newly developed sarcopenia was an independent negative predictor for post-LT survival (hazard ratio: 10.53, 95% confidence interval: 1.37-80.93, p = 0.024.Sarcopenia in LT recipients did not improve in any of the previously sarcopenic patients and newly developed within 1 year in others. Newly developed sarcopenia was associated with increased mortality. Newly developed sarcopenia can be used to stratify patients with regard to the risk of post-LT mortality.

  11. Adaptive Dynamics, Control, and Extinction in Networked Populations

    Science.gov (United States)

    2015-07-09

    extinction . VI. CONCLUSIONS We have presented a method for predicting extinction in stochastic network systems by analyzing a pair-based proxy model...including games on networks (e.g., [40], [41]). Further, we expect that our method of continuously varying a parameter while tracking the path to extinction ...Adaptive Dynamics, Control, and Extinction in Networked Populations Ira B. Schwartz US Naval Research Laboratory Code 6792 Nonlinear System Dynamics

  12. Power spectra of extinction in the fossil record

    OpenAIRE

    Newman, M. E. J.; Eble, Gunther J.

    1998-01-01

    Recent Fourier analyses of fossil extinction data have indicated that the power spectrum of extinction during the Phanerozoic may take the form of 1/f noise, a result which, it has been suggested, could be indicative of the presence of `critical dynamics' in the processes giving rise to extinction. In this paper we examine extinction power spectra in some detail, using family-level data from two widely available compilations. We find that although the average form of the power spectrum roughl...

  13. Fibroblast Growth Factor-2 Alters the Nature of Extinction

    Science.gov (United States)

    Graham, Bronwyn M.; Richardson, Rick

    2011-01-01

    These experiments examined the effects of the NMDA-receptor (NMDAr) antagonist MK801 on reacquisition and re-extinction of a conditioned fear that had been previously extinguished before injection of fibroblast growth factor-2 (FGF2) or vehicle. Recent findings have shown that relearning and re-extinction, unlike initial learning and extinction,…

  14. Malthusian Catastrophe: Species Extinction Caused By Oversized Population

    OpenAIRE

    Pan, Xubin

    2017-01-01

    There is one pseudo-extinction debt and four occurring conditions for real extinction debt. Since small and oversized populations have a high extinction risk, Pan threshold (upper limit) was calculated for Verhulst-Pear logistic growth model and logistic model with the Allee effect, an important parameter corresponding to Allee threshold (lower limit).

  15. Inhibition of Estradiol Synthesis Impairs Fear Extinction in Male Rats

    Science.gov (United States)

    Graham, Bronwyn M.; Milad, Mohammed R.

    2014-01-01

    Emerging research has demonstrated that the sex hormone estradiol regulates fear extinction in female rodents and women. Estradiol may also regulate fear extinction in males, given its role in synaptic plasticity in both sexes. Here we report that inhibition of estradiol synthesis during extinction training, via the aromatase inhibitor fadrozole,…

  16. Deficits in the extinction of ethanol-seeking behavior following chronic intermittent ethanol exposure are attenuated with positive allosteric modulation of mGlu5.

    Science.gov (United States)

    Gass, J T; McGonigal, J T; Chandler, L J

    2017-02-01

    Alcoholism is a chronic relapsing disorder characterized by periods of heavy alcohol consumption and unsuccessful attempts at abstinence. Relapse is one of the most problematic aspects in the treatment of alcoholism and is triggered by ethanol-associated cues. Extinction-based cue exposure therapies have proven ineffective in the treatment of alcoholism. However, positive allosteric modulation of mGlu5 with CDPPB enhances the extinction learning of alcohol-seeking behavior. The current study investigated the impact of chronic alcohol exposure on the extinction of ethanol-seeking behavior. Adult Wistar rats were trained to self-administer alcohol with a light/tone stimulus serving as the alcohol cue. After training, one group of rats was exposed to chronic intermittent ethanol (CIE) daily for a period of 2 weeks to induce ethanol dependence. Control rats were exposed to air for the same period of time. Both groups were then retrained to self-administer ethanol and subsequently tested for changes in extinction learning. CIE exposed rats consumed more ethanol compared to their pre-CIE levels and to control rats. During extinction training, CIE rats responded significantly more on the previously active lever and required more sessions to reach extinction criteria compared to control rats. Treatment with CDPPB facilitated extinction in control rats and attenuated the increased resistance to extinction in CIE-exposed rats. These results demonstrate that chronic ethanol exposure not only alters ethanol intake, but also the extinction of ethanol-seeking behaviors. The ability to attenuate deficits through modulation of mGlu5 provides a potential target for pharmacological manipulation that could ultimately reduce relapse in alcoholics. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Extinction of chained instrumental behaviors: Effects of consumption extinction on procurement responding.

    Science.gov (United States)

    Thrailkill, Eric A; Bouton, Mark E

    2016-03-01

    Operant behavior is typically organized into sequences of responses that eventually lead to a reinforcer. Response elements can be categorized as those that directly lead to reward consumption (i.e., a consumption response) and those that lead to the opportunity to make the consumption response (i.e., a procurement response). These responses often differ topographically and in terms of the discriminative stimuli that set the occasion for them. We have recently shown that extinction of the procurement response acts to weaken the specific associated consumption response, and that active inhibition of the procurement response is required for this effect. To expand the analysis of the associative structure of chains, in the present experiments we asked the reverse question: whether extinction of consumption behavior results in a decrease in the associated procurement response in a discriminated heterogeneous chain. In Experiment 1, extinction of consumption alone led to an attenuation of the associated procurement response only when rats were allowed to make the consumption response in extinction. Exposure to the consumption stimulus alone was not sufficient to produce weakened procurement responding. In Experiment 2, rats learned two distinct heterogeneous chains, and extinction of one consumption response specifically weakened the procurement response associated with it. The results add to the evidence suggesting that rats learn a highly specific associative structure in behavior chains, emphasizing the role of learning response inhibition in extinction.

  18. Session-RPE for quantifying the load of different youth basketball training sessions.

    Science.gov (United States)

    Lupo, C; Tessitore, A; Gasperi, L; Gomez, Mar

    2017-03-01

    The aim of the study was to evaluate youth basketball training, verifying the reliability of the session-RPE method in relation to session duration (basketball players (age, 16.5±0.5 years; height, 195.5±6.75 cm; body mass, 93.9±10.9 kg; and body mass index, 23.6±2.8 kg.m -2 ) were monitored (HR, type and duration of workouts) during 15 (66 individual) training sessions (80±26 minutes). Edwards' HR method was used as a reference measure of internal training load (ITL); the CR-10 RPE scale was administered 30 minutes after the end of each session. The results obtained showed that all comparisons between different session durations and workout portions revealed effects in term of Edwards' ITLs except for warm-up portions. Moderate to strong relationships between Edwards' and session- RPE methods emerged for all sessions (r = .85, P basketball players can successfully use session-RPE to monitor the ITL, regardless of session durations and workout portions.

  19. Can Transcranial Direct Current Stimulation Augment Extinction of Conditioned Fear?

    Science.gov (United States)

    van ’t Wout, Mascha; Mariano, Timothy Y.; Garnaat, Sarah L.; Reddy, Madhavi K.; Rasmussen, Steven A.; Greenberg, Benjamin D.

    2016-01-01

    Background Exposure-based therapy parallels extinction learning of conditioned fear. Prior research points to the ventromedial prefrontal cortex as a potential site for the consolidation of extinction learning and subsequent retention of extinction memory. Objective/hypothesis The present study aimed to evaluate whether the application of non-invasive transcranial direct current stimulation (tDCS) during extinction learning enhances late extinction and early recall in human participants. Methods Forty-four healthy volunteers completed a 2-day Pavlovian fear conditioning, extinction, and recall paradigm while skin conductance activity was continuously measured. Twenty-six participants received 2 mA anodal tDCS over EEG coordinate AF3 during extinction of a first conditioned stimulus. The remaining 18 participants received similar tDCS during extinction of a second conditioned stimulus. Sham stimulation was applied for the balance of extinction trials in both groups. Normalized skin conductance changes were analyzed using linear mixed models to evaluate effects of tDCS over late extinction and early recall trials. Results We observed a significant interaction between timing of tDCS during extinction blocks and changes in skin conductance reactivity over late extinction trials. These data indicate that tDCS was associated with accelerated late extinction learning of a second conditioned stimulus after tDCS was combined with extinction learning of a previous conditioned stimulus. No significant effects of tDCS timing were observed on early extinction recall. Conclusions Results could be explained by an anxiolytic aftereffect of tDCS and extend previous studies on tDCS-induced modulation of fear and threat related learning processes. These findings support further exploration of the clinical use of tDCS. PMID:27037186

  20. Acquisition, consolidation, reconsolidation, and extinction of eyelid conditioning responses require de novo protein synthesis.

    Science.gov (United States)

    Inda, Mari Carmen; Delgado-García, José María; Carrión, Angel Manuel

    2005-02-23

    Memory, as measured by changes in an animal's behavior some time after learning, is a reflection of many processes. Here, using a trace paradigm, in mice we show that de novo protein synthesis is required for acquisition, consolidation, reconsolidation, and extinction of classically conditioned eyelid responses. Two critical periods of protein synthesis have been found: the first, during training, the blocking of which impaired acquisition; and the second, lasting the first 4 h after training, the blocking of which impaired consolidation. The process of reconsolidation was sensitive to protein synthesis inhibition if anisomycin was injected before or just after the reactivation session. Furthermore, extinction was also dependent on protein synthesis, following the same temporal course as that followed during acquisition and consolidation. This last fact reinforces the idea that extinction is an active learning process rather than a passive event of forgetting. Together, these findings demonstrate that all of the different stages of memory formation involved in the classical conditioning of eyelid responses are dependent on protein synthesis.

  1. Intersections and Unions of Session Types

    Directory of Open Access Journals (Sweden)

    Coşku Acay

    2017-02-01

    Full Text Available Prior work has extended the deep, logical connection between the linear sequent calculus and session-typed message-passing concurrent computation with equi-recursive types and a natural notion of subtyping. In this paper, we extend this further by intersection and union types in order to express multiple behavioral properties of processes in a single type. We prove session fidelity and absence of deadlock and illustrate the expressive power of our system with some simple examples. We observe that we can represent internal and external choice by intersection and union, respectively, which was previously suggested by Padovani for a different language of session types motivated by operational rather than logical concerns.

  2. Poster session in instructional technology course

    Science.gov (United States)

    Diniaty, Artina; Fauzi'ah, Lina; Wulan Febriana, Beta; Arlianty, Widinda Normalia

    2017-12-01

    Instructional technology course must be studied by students in order to 1) understand the role of technology in learning, 2) capable of analyzing advantages and disadvantages of using technology in teaching, 3) capable of performing technology in teaching. A poster session in instructional technology course was performed to 1) enhance students' interest in this course and develop students' creativity. The step of this research includes: planning, implementation, and evaluation. The result showed that students' responses towards poster session in instructional technology course were good.

  3. Summary of Session 2 "Machine Studies"

    CERN Document Server

    Assmann, R W

    2012-01-01

    This document summarizes the talks and discussion that took place in the second session of the Chamonix 2012 workshop concerning results from machine studies performed in 2011. The session consisted of the following presentations: “LHC experience with different bunch spacings” by G. Rumolo; “Observations of beam-beam effects in MDs in 2011” by W. Herr; “Beam-induced heating/ bunch length/RF and lessons for 2012” by E. Metral; “Lessons in beam diagnostics” by R. Jones; “Quench margins” by M. Sapinski; “First demonstration with beam of the Achromatic Telescopic Squeeze (ATS)” by S. Fartoukh.

  4. Decline and local extinction of Fucales in French Riviera: the harbinger of future extinctions?

    Directory of Open Access Journals (Sweden)

    T. THIBAUT

    2014-03-01

    Full Text Available The French Riviera is one of the Mediterranean areas that has been longest and most thoroughly impacted by human activities. Fucales are long-lived, large-sized brown algae that constitute a good model for studying human impact on species diversity. We gathered all historical data (literature and herbarium vouchers, since the early 19th century, to reconstruct their distribution. The current distribution was established from a 7-year (2007-2013 survey of the 212-km shoreline (1/2 500 map, by means of boating, snorkelling and scuba diving. Overall, 18 taxa of Cystoseira and Sargassum have been reported. Upon comparison with historical data, 5 taxa were no longer observed (C. elegans, C. foeniculacea f. latiramosa, C. squarrosa, C. spinosa var. spinosa and S. hornschuchii while C. jabukae, previously unrecorded, was observed. In addition to these  taxa, probably extinct at a local scale, some taxa had suffered a dramatic decline (C. barbata f. barbata, C. crinita, C. spinosa var. compressa and S. acinarium or become nearly extinct (C. foeniculacea f. tenuiramosa. Three of them, which played in the past significant functional roles in coastal communities, can be considered as functionally extinct. Possible causes of decline and local extinction are discussed. A similar situation has already been reported, although at a much more local scale, in a variety of Mediterranean localities. The question therefore arises about the status of Fucales species in the Mediterranean: are some species on the brink of extinction? Is their extinction at the scale of the French Riviera the harbinger of their extinction Mediterranean–wide?

  5. Predicting extinction risk of Brazilian Atlantic forest angiosperms.

    Science.gov (United States)

    Leão, Tarciso C C; Fonseca, Carlos R; Peres, Carlos A; Tabarelli, Marcelo

    2014-10-01

    Understanding how plant life history affects species vulnerability to anthropogenic disturbances and environmental change is a major ecological challenge. We examined how vegetation type, growth form, and geographic range size relate to extinction risk throughout the Brazilian Atlantic Forest domain. We used a database containing species-level information of 6,929 angiosperms within 112 families and a molecular-based working phylogeny. We used decision trees, standard regression, and phylogenetic regression to explore the relationships between species attributes and extinction risk. We found a significant phylogenetic signal in extinction risk. Vegetation type, growth form, and geographic range size were related to species extinction risk, but the effect of growth form was not evident after phylogeny was controlled for. Species restricted to either rocky outcrops or scrub vegetation on sandy coastal plains exhibited the highest extinction risk among vegetation types, a finding that supports the hypothesis that species adapted to resource-limited environments are more vulnerable to extinction. Among growth forms, epiphytes were associated with the highest extinction risk in non-phylogenetic regression models, followed by trees, whereas shrubs and climbers were associated with lower extinction risk. However, the higher extinction risk of epiphytes was not significant after correcting for phylogenetic relatedness. Our findings provide new indicators of extinction risk and insights into the mechanisms governing plant vulnerability to extinction in a highly diverse flora where human disturbances are both frequent and widespread. © 2014 Society for Conservation Biology.

  6. A global synthesis of plant extinction rates in urban areas.

    Science.gov (United States)

    Hahs, Amy K; McDonnell, Mark J; McCarthy, Michael A; Vesk, Peter A; Corlett, Richard T; Norton, Briony A; Clemants, Steven E; Duncan, Richard P; Thompson, Ken; Schwartz, Mark W; Williams, Nicholas S G

    2009-11-01

    Plant extinctions from urban areas are a growing threat to biodiversity worldwide. To minimize this threat, it is critical to understand what factors are influencing plant extinction rates. We compiled plant extinction rate data for 22 cities around the world. Two-thirds of the variation in plant extinction rates was explained by a combination of the city's historical development and the current proportion of native vegetation, with the former explaining the greatest variability. As a single variable, the amount of native vegetation remaining also influenced extinction rates, particularly in cities > 200 years old. Our study demonstrates that the legacies of landscape transformations by agrarian and urban development last for hundreds of years, and modern cities potentially carry a large extinction debt. This finding highlights the importance of preserving native vegetation in urban areas and the need for mitigation to minimize potential plant extinctions in the future.

  7. Reactivated Memories Compete for Expression After Pavlovian Extinction

    Science.gov (United States)

    Laborda, Mario A.; Miller, Ralph R.

    2012-01-01

    We view the response decrement resulting from extinction treatment as an interference effect, in which the reactivated memory from acquisition competes with the reactivated memory from extinction for behavioral expression. For each of these memories, reactivation is proportional to both the strength of the stimulus-outcome association and the quality of the facilitatory cues for that association which are present at test. Here we review basic extinction and recovery-from-extinction phenomena, showing how these effects are explicable in this associative interference framework. Moreover, this orientation has and continues to dictate efficient manipulations for minimizing recovery from extinction. This in turn suggests procedures that might reduce relapse from exposure therapy for a number of psychological disorders. Some of these manipulations enhance the facilitatory cues from extinction that are present at test, others strengthen the extinction association (i.e., CS-no outcome), and yet others seem to work by a combination of these two processes. PMID:22326812

  8. Running from fear: Exercise modulation of fear extinction.

    Science.gov (United States)

    Tanner, Margaret K; Hake, Holly S; Bouchet, Courtney A; Greenwood, Benjamin N

    2018-03-31

    Extinction-based exposure therapy is the most common behavioral therapy for anxiety and trauma-related disorders, but fear tends to resurface even after successful extinction. Identification of novel strategies to enhance fear extinction and reduce fear relapse is of paramount importance to mental health. Exercise can enhance cognitive function, but it is not yet well understood whether exercise can be an effective augmentation strategy for fear extinction. In the current review, we present the current state of knowledge on the effects of exercise on fear extinction. Effects of exercise duration, explanations for conflicting results, and potential mechanisms, focusing on a hypothesized role for dopamine, are all discussed. We also provide new data suggesting that the timing in which acute exercise occurs relative to fear extinction, is a crucial variable in determining whether exercise can enhance fear extinction. Clinical implications and ideas to guide future research endeavors in this area are provided. Copyright © 2018 Elsevier Inc. All rights reserved.

  9. Allee dynamics: Growth, extinction and range expansion

    Science.gov (United States)

    Bose, Indrani; Pal, Mainak; Karmakar, Chiranjit

    In population biology, the Allee dynamics refer to negative growth rates below a critical population density. In this paper, we study a reaction-diffusion (RD) model of popoulation growth and dispersion in one dimension, which incorporates the Allee effect in both the growth and mortatility rates. In the absence of diffusion, the bifurcation diagram displays regions of both finite population density and zero population density, i.e. extinction. The early signatures of the transition to extinction at the bifurcation point are computed in the presence of additive noise. For the full RD model, the existence of traveling wave solutions of the population density is demonstrated. The parameter regimes in which the traveling wave advances (range expansion) and retreats are identified. In the weak Allee regime, the transition from the pushed to the pulled wave is shown as a function of the mortality rate constant. The results obtained are in agreement with the recent experimental observations on budding yeast populations.

  10. Extinction of corrugated hydrogen/air flames

    International Nuclear Information System (INIS)

    Mizomoto, M.; Asaka, Y.; Ikai, S.; Law, C.K.

    1982-01-01

    Recent studies on flammability limits reveal the importance of flow nonuniformity, flame curvature, and molecular and thermal diffusivities in determining the extinguishability and the associated limits of premixed fuel/air flames. In particular, it is found that conditions which favor extinction of a lean flame may cause intensification of a rich flame. In the present study the authors have experimentally determined the extinction characteristics and limits of highly curved hydrogen/air flames as represented by the opening of bunsen flame tips. Results show that the tip opens at a constant fuel equivalence ratio of phi = 1.15, regardless of the velocity and uniformity of the upstream flow. This critical mixture concentration, while being rich, is still on the lean side of that corresponding to the maximum burning velocity (phi = 1.8), implying that for highly diffusive systems, the relevant reference concentration is that for maximum burning velocity instead of stoichiometry

  11. Visuomotor links in awareness: evidence from extinction.

    Science.gov (United States)

    Ricci, Raffaella; Genero, Rosanna; Colombatti, Simona; Zampieri, Daniela; Chatterjee, Anjan

    2005-05-31

    In patients with extinction, ipsilesional stimuli may abolish awareness of contralesional stimuli. Explanations of extinction often assume a serial model of processing in which sensory competition and identification precedes the selection of responses. We tested the adequacy of this assumption by examining the effects of response variables on visual awareness in six patients using signal detection analysis. Ipsilesional stimuli modulated patients' response criteria in deciding whether a contralesional stimulus was a target, and response modality (verbal or motor) modulated patients' abilities to discriminate between contralesional targets and distractors. This pattern of input variables modulating response criteria and output variables modulating discriminability indicates the extent to which attentional and intentional systems are tightly intertwined, with bi-directional effects in producing visual awareness.

  12. Immunological systematics of the extinct quagga (Equidae).

    Science.gov (United States)

    Lowenstein, J M; Ryder, O A

    1985-09-15

    It has been debated whether the extinct quagga was a distinct fourth species of African zebra or whether it was merely the southern variant of the Plains zebra (Equus burchelli). Using a radioimmunoassay (RIA) technique, we have shown that proteins remaining in quagga skins from museums are much more similar to serum proteins of the Plains zebra than to those of the other two extant zebras.

  13. Neural Mechanisms of Extinction Learning and Retrieval

    OpenAIRE

    Quirk, Gregory J.; Mueller, Devin

    2007-01-01

    Emotional learning is necessary for individuals to survive and prosper. Once acquired, however, emotional associations are not always expressed. Indeed, the regulation of emotional expression under varying environmental conditions is essential for mental health. The simplest form of emotional regulation is extinction, in which conditioned responding to a stimulus decreases when the reinforcer is omitted. Two decades of research on the neural mechanisms of fear conditioning have laid the groun...

  14. Opportunities and costs for preventing vertebrate extinctions.

    Science.gov (United States)

    Conde, Dalia A; Colchero, Fernando; Güneralp, Burak; Gusset, Markus; Skolnik, Ben; Parr, Michael; Byers, Onnie; Johnson, Kevin; Young, Glyn; Flesness, Nate; Possingham, Hugh; Fa, John E

    2015-03-16

    Despite an increase in policy and management responses to the global biodiversity crisis, implementation of the 20 Aichi Biodiversity Targets still shows insufficient progress [1]. These targets, strategic goals defined by the United Nations Convention on Biological Diversity (CBD), address major causes of biodiversity loss in part by establishing protected areas (Target 11) and preventing species extinctions (Target 12). To achieve this, increased interventions will be required for a large number of sites and species. The Alliance for Zero Extinction (AZE) [2], a consortium of conservation-oriented organisations that aims to protect Critically Endangered and Endangered species restricted to single sites, has identified 920 species of mammals, birds, amphibians, reptiles, conifers and reef-building corals in 588 'trigger' sites [3]. These are arguably the most irreplaceable category of important biodiversity conservation sites. Protected area coverage of AZE sites is a key indicator of progress towards Target 11 [1]. Moreover, effective conservation of AZE sites is essential to achieve Target 12, as the loss of any of these sites would certainly result in the global extinction of at least one species [2]. However, averting human-induced species extinctions within AZE sites requires enhanced planning tools to increase the chances of success [3]. Here, we assess the potential for ensuring the long-term conservation of AZE vertebrate species (157 mammals, 165 birds, 17 reptiles and 502 amphibians) by calculating a conservation opportunity index (COI) for each species. The COI encompasses a set of measurable indicators that quantify the possibility of achieving successful conservation of a species in its natural habitat (COIh) and by establishing insurance populations in zoos (COIc). Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Rewinding the process of mammalian extinction

    OpenAIRE

    Saragusty, J.; Diecke, S.; Drukker, M.; Durrant, B.; Friedrich Ben-Nun, I.; Galli, C.; Goeritz, F.; Hayashi, K.; Hermes, R.; Holtze, S.; Johnson, S.; Lazzari, G.; Loi, P.; Loring, J.F.; Okita, K.

    2016-01-01

    With only three living individuals left on this planet, the northern white rhinoceros (Ceratotherium simum cottoni) could be considered doomed for extinction. It might still be possible, however, to rescue the (sub)species by combining novel stem cell and assisted reproductive technologies. To discuss the various practical options available to us, we convened a multidisciplinary meeting under the name "Conservation by Cellular Technologies." The outcome of this meeting and the proposed road m...

  16. Parrots and macaws: Species in extinction danger?

    International Nuclear Information System (INIS)

    Castro ramirez, Jose; Moyano P, Edgar A

    1994-01-01

    The paper refers to the privileged position of Colombia due to their position in the tropic, the influence of two oceans, their wide hydrographic net, variety of climates, etc; they make that Colombia occupies first places in biodiversity; but due to the indiscriminate pruning of primary forest, they make that this enormous biological potential is seriously threatened, where many of its birds are in extinction road

  17. Causes and timing of future biosphere extinctions

    Directory of Open Access Journals (Sweden)

    S. Franck

    2006-01-01

    Full Text Available We present a minimal model for the global carbon cycle of the Earth containing the reservoirs mantle, ocean floor, continental crust, biosphere, and the kerogen, as well as the combined ocean and atmosphere reservoir. The model is specified by introducing three different types of biosphere: procaryotes, eucaryotes, and complex multicellular life. During the entire existence of the biosphere procaryotes are always present. 2 Gyr ago eucaryotic life first appears. The emergence of complex multicellular life is connected with an explosive increase in biomass and a strong decrease in Cambrian global surface temperature at about 0.54 Gyr ago. In the long-term future the three types of biosphere will die out in reverse sequence of their appearance. We show that there is no evidence for an implosion-like extinction in contrast to the Cambrian explosion. In dependence of their temperature tolerance complex multicellular life and eucaryotes become extinct in about 0.8–1.2 Gyr and 1.3–1.5 Gyr, respectively. The ultimate life span of the biosphere is defined by the extinction of procaryotes in about 1.6 Gyr.

  18. Area-based assessment of extinction risk.

    Science.gov (United States)

    Hei, Fangliang

    2012-05-01

    Underpinning the International Union for Conservation of Nature (IUCN) Red List is the assessment of extinction risk as determined by the size and degree of loss of populations. The IUCN system lists a species as Critically Endangered, Endangered, or Vulnerable if its population size declines 80%, 50%, or 30% within a given time frame. However, effective implementation of the system faces substantial challenges and uncertainty because geographic scale data on population size and long-term dynamics are scarce. I develop a model to quantify extinction risk using a measure based on a species' distribution, a much more readily obtained quantity. The model calculates the loss of the area of occupancy that is equivalent to the loss of a given proportion of a population. It is a very simple yet general model that has no free parameters and is independent of scale. The model predicted well the distributions of 302 tree species at a local scale and the distributions of 348 species of North American land birds. This area-based model provides a solution to the long-standing problem for IUCN assessments of lack of data on population sizes, and thus it will contribute to facilitating the quantification of extinction risk worldwide.

  19. Survivability of a metapopulation under local extinctions

    Science.gov (United States)

    Kundu, Srilena; Majhi, Soumen; Sasmal, Sourav Kumar; Ghosh, Dibakar; Rakshit, Biswambhar

    2017-12-01

    A metapopulation structure in landscape ecology comprises a group of interacting spatially separated subpopulations or patches of the same species that may experience several local extinctions. This makes the investigation of survivability (in the form of global oscillation) of a metapopulation on top of diverse dispersal topologies extremely crucial. However, among various dispersal topologies in ecological networks, which one can provide higher metapopulation survivability under local extinction is still not well explored. In this article, we scrutinize the robustness of an ecological network consisting of prey-predator patches having Holling type I functional response, against progressively extinct population patches. We present a comprehensive study on this while considering global, small-world, and scale-free dispersal of the subpopulations. Furthermore, we extend our work in enhancing survivability in the form of sustained global oscillation by introducing asymmetries in the dispersal rates of the considered species. Our findings affirm that the asynchrony among the patches plays an important role in the survivability of a metapopulation. In order to demonstrate the model independence of the observed phenomenon, we perform a similar analysis for patches exhibiting Holling type II functional response. On the grounds of the obtained results, our work is expected to provide a better perception of the influence of dispersal arrangements on the global survivability of ecological networks.

  20. Interstellar Extinction in 20 Open Star Clusters

    Science.gov (United States)

    Rangwal, Geeta; Yadav, R. K. S.; Durgapal, Alok K.; Bisht, D.

    2017-12-01

    The interstellar extinction law in 20 open star clusters namely, Berkeley 7, Collinder 69, Hogg 10, NGC 2362, Czernik 43, NGC 6530, NGC 6871, Bochum 10, Haffner 18, IC 4996, NGC 2384, NGC 6193, NGC 6618, NGC 7160, Collinder 232, Haffner 19, NGC 2401, NGC 6231, NGC 6823, and NGC 7380 have been studied in the optical and near-IR wavelength ranges. The difference between maximum and minimum values of E(B - V) indicates the presence of non-uniform extinction in all the clusters except Collinder 69, NGC 2362, and NGC 2384. The colour excess ratios are consistent with a normal extinction law for the clusters NGC 6823, Haffner 18, Haffner 19, NGC 7160, NGC 6193, NGC 2401, NGC 2384, NGC 6871, NGC 7380, Berkeley 7, Collinder 69, and IC 4996. We have found that the differential colour-excess ΔE(B - V), which may be due to the occurrence of dust and gas inside the clusters, decreases with the age of the clusters. A spatial variation of colour excess is found in NGC 6193 in the sense that it decreases from east to west in the cluster region. For the clusters Berkeley 7, NGC 7380, and NGC 6871, a dependence of colour excess E(B - V) with spectral class and luminosity is observed. Eight stars in Collinder 232, four stars in NGC 6530, and one star in NGC 6231 have excess flux in near-IR. This indicates that these stars may have circumstellar material around them.

  1. In Situ Measurement of Aerosol Extinction

    Science.gov (United States)

    Strawa, Anthony W.; Castaneda, R.; Owano, T. G.; Bear, D.; Gore, Warren J. (Technical Monitor)

    2001-01-01

    Aerosols are important contributors to the radiative forcing in the atmosphere. Much of the uncertainty in our knowledge of climate forcing is due to uncertainties in the radiative forcing due to aerosols as illustrated in the IPCC reports of the last ten years. Improved measurement of aerosol optical properties, therefore, is critical to an improved understanding of atmospheric radiative forcing. Additionally, attempts to reconcile in situ and remote measurements of aerosol radiative properties have generally not been successful. This is due in part to the fact that it has been impossible to measure aerosol extinction in situ in the past. In this presentation we introduce a new instrument that employs the techniques used in cavity ringdown spectroscopy to measure the aerosol extinction and scattering coefficients in situ. A prototype instrument has been designed and tested in the lab and the field. It is capable of measuring aerosol extinction coefficient to 2x10(exp -6) per meter. This prototype instrument is described and results are presented.

  2. Rewinding the process of mammalian extinction.

    Science.gov (United States)

    Saragusty, Joseph; Diecke, Sebastian; Drukker, Micha; Durrant, Barbara; Friedrich Ben-Nun, Inbar; Galli, Cesare; Göritz, Frank; Hayashi, Katsuhiko; Hermes, Robert; Holtze, Susanne; Johnson, Stacey; Lazzari, Giovanna; Loi, Pasqualino; Loring, Jeanne F; Okita, Keisuke; Renfree, Marilyn B; Seet, Steven; Voracek, Thomas; Stejskal, Jan; Ryder, Oliver A; Hildebrandt, Thomas B

    2016-07-01

    With only three living individuals left on this planet, the northern white rhinoceros (Ceratotherium simum cottoni) could be considered doomed for extinction. It might still be possible, however, to rescue the (sub)species by combining novel stem cell and assisted reproductive technologies. To discuss the various practical options available to us, we convened a multidisciplinary meeting under the name "Conservation by Cellular Technologies." The outcome of this meeting and the proposed road map that, if successfully implemented, would ultimately lead to a self-sustaining population of an extremely endangered species are outlined here. The ideas discussed here, while centered on the northern white rhinoceros, are equally applicable, after proper adjustments, to other mammals on the brink of extinction. Through implementation of these ideas we hope to establish the foundation for reversal of some of the effects of what has been termed the sixth mass extinction event in the history of Earth, and the first anthropogenic one. Zoo Biol. 35:280-292, 2016. © 2016 The Authors. Zoo Biology published by Wiley Periodicals, Inc. © 2016 The Authors. Zoo Biology published by Wiley Periodicals, Inc.

  3. The functional extinction of Andean megafauna.

    Science.gov (United States)

    Rozas-Davila, Angela; Valencia, Bryan G; Bush, Mark B

    2016-10-01

    Controversy exists over the cause and timing of the extinction of the Pleistocene megafauna. In the tropical Andes, deglaciation and associated rapid climate change began ~8,000 years before human arrival, providing an opportunity to separate the effects of climate change from human hunting on megafaunal extinction. We present a paleoecological record spanning the last 25,000 years from Lake Pacucha, Peru (3,100 m elevation). Fossil pollen, charcoal, diatoms, and the dung fungus Sporormiella, chronicle a two-stage megaherbivore population collapse. Sporormiella abundance, the proxy for megafaunal presence, fell sharply at ~21,000 years ago, but rebounded prior to a permanent decline between ~16,800 and 15,800 years ago. This two-stage decline in megaherbivores resulted in a functional extinction by ~15,800 years ago, 3,000 years earlier than known human occupation of the high Andes. Declining megaherbivore populations coincided with warm, wet intervals. Climatic instability and megafaunal population collapse triggered an ecological cascade that resulted in novel floral assemblages, and increases in woody species, fire frequency, and plant species that were sensitive to trampling. Our data revealed that Andean megafaunal populations collapsed due to positive feedbacks between habitat quality and climate change rather than human activity. © 2016 by the Ecological Society of America.

  4. AN ANALYSIS OF THE SHAPES OF INTERSTELLAR EXTINCTION CURVES. VI. THE NEAR-IR EXTINCTION LAW

    International Nuclear Information System (INIS)

    Fitzpatrick, E. L.; Massa, D.

    2009-01-01

    We combine new observations from the Hubble Space Telescope's Advanced Camera of Survey with existing data to investigate the wavelength dependence of near-IR (NIR) extinction. Previous studies suggest a power law form for NIR extinction, with a 'universal' value of the exponent, although some recent observations indicate that significant sight line-to-sight line variability may exist. We show that a power-law model for the NIR extinction provides an excellent fit to most extinction curves, but that the value of the power, β, varies significantly from sight line to sight line. Therefore, it seems that a 'universal NIR extinction law' is not possible. Instead, we find that as β decreases, R(V) ≡ A(V)/E(B - V) tends to increase, suggesting that NIR extinction curves which have been considered 'peculiar' may, in fact, be typical for different R(V) values. We show that the power-law parameters can depend on the wavelength interval used to derive them, with the β increasing as longer wavelengths are included. This result implies that extrapolating power-law fits to determine R(V) is unreliable. To avoid this problem, we adopt a different functional form for NIR extinction. This new form mimics a power law whose exponent increases with wavelength, has only two free parameters, can fit all of our curves over a longer wavelength baseline and to higher precision, and produces R(V) values which are consistent with independent estimates and commonly used methods for estimating R(V). Furthermore, unlike the power-law model, it gives R(V)s that are independent of the wavelength interval used to derive them. It also suggests that the relation R(V) = -1.36 E(K-V)/(E(B-V)) - 0.79 can estimate R(V) to ±0.12. Finally, we use model extinction curves to show that our extinction curves are in accord with theoretical expectations, and demonstrate how large samples of observational quantities can provide useful constraints on the grain properties.

  5. Extinction of Chained Instrumental Behaviors: Effects of Procurement Extinction on Consumption Responding

    Science.gov (United States)

    Thrailkill, Eric A.; Bouton, Mark E.

    2015-01-01

    Instrumental behavior often consists of sequences or chains of responses that minimally include procurement behaviors that enable subsequent consumption behaviors. In such chains, behavioral units are linked by access to one another and eventually to a primary reinforcer, such as food or a drug. The present experiments examined the effects of extinguishing procurement responding on consumption responding after training of a discriminated heterogeneous instrumental chain. Rats learned to make a procurement response (e.g., pressing a lever) in the presence of a distinctive discriminative stimulus; making that response led to the presentation of a second discriminative stimulus that set the occasion for a consumption response (e.g., pulling a chain), which then produced a food-pellet reinforcer. Experiment 1 showed that extinction of either the full procurement-consumption chain or procurement alone weakened the consumption response tested in isolation. Experiment 2 replicated the procurement extinction effect and further demonstrated that the opportunity to make the procurement response, as opposed to simple exposure to the procurement stimulus alone, was required. In Experiment 3, rats learned 2 distinct discriminated heterogeneous chains; extinction of 1 procurement response specifically weakened the consumption response that had been associated with it. The results suggest that learning to inhibit the procurement response may produce extinction of consumption responding through mediated extinction. The experiments suggest the importance of an associative analysis of instrumental behavior chains. PMID:25915751

  6. IAEA General Conference begins annual session

    International Nuclear Information System (INIS)

    2001-01-01

    The document gives general information about the opening and the programme of the 45th regular session of the IAEA General Conference (17-21 September 2001, Austria Center Vienna). The conference is attended by ministers and high-level governmental representatives from 132 Member States of the IAEA

  7. Declarative interpretations of session-based concurrency

    DEFF Research Database (Denmark)

    Cano, Mauricio; Rueda, Camilo; López-Acosta, Hugo-Andrés

    2015-01-01

    Session-based concurrency is a type-based approach to the analysis of communication-intensive systems. Correct behavior in these systems may be specified in an operational or declarative style: the former defines how interactions are structured; the latter defines governing conditions...

  8. Foundations of Session Types and Behavioural Contracts

    DEFF Research Database (Denmark)

    Huttel, Hans; Lanese, Ivan; Vasconcelos, Vasco

    2016-01-01

    of interaction using expressive type languages, so types can be used to determine automatically whether the component interacts correctly with other components. Two related important notions of behavioural types are those of session types and behavioural contracts. This article surveys the main accomplishments...

  9. Posters. [Poster Session at AHRD Conference, 2001].

    Science.gov (United States)

    2001

    The first of the papers in this poster session, "Developing the Employment Brand: Targeting MBA Campus Hires" (Diane M. Bergeron), posits that employment branding benefits both individuals and organizations. It functions as a campus recruiting tool in a competitive labor market and communicates the organization's values and work…

  10. An Erlang Implementation of Multiparty Session Actors

    Directory of Open Access Journals (Sweden)

    Simon Fowler

    2016-08-01

    Full Text Available By requiring co-ordination to take place using explicit message passing instead of relying on shared memory, actor-based programming languages have been shown to be effective tools for building reliable and fault-tolerant distributed systems. Although naturally communication-centric, communication patterns in actor-based applications remain informally specified, meaning that errors in communication are detected late, if at all. Multiparty session types are a formalism to describe, at a global level, the interactions between multiple communicating entities. This article describes the implementation of a prototype framework for monitoring Erlang/OTP gen_server applications against multiparty session types, showing how previous work on multiparty session actors can be adapted to a purely actor-based language, and how monitor violations and termination of session participants can be reported in line with the Erlang mantra of "let it fail". Finally, the framework is used to implement two case studies: an adaptation of a freely-available DNS server, and a chat server.

  11. Organizing a Practice Session for Maximum Effectiveness

    Science.gov (United States)

    DeGroot, Joanna

    2009-01-01

    According to Jason Paulk, director of choral activities at Eastern New Mexico University, progress is made during those in-between times and that progress magnifies with efficient time spent alone. Paulk is a firm believer in the importance of singers organizing their practice sessions, and he details some effective organization methods, including…

  12. Extinction and polarization of light by dust in the interstellar medium. Interstellar extinction curves

    International Nuclear Information System (INIS)

    Voshchinnokov, N.V.; Il'in, A.E.; Il'in, V.B.

    1986-01-01

    A model of two-layer cylindrical interstellar dust grains is used to calculate the interstellar extinction curves in the visible and near infrared regions of the spectrum and the ratio R /sub V/ of the total to the selective extinction. It is assumed that the core of the two-layer grains consists of ''astronomical silicate'' and the mantle of dirty ice and that they are completely or partly oriented under the influence of the Davis-Greenstein mechanism. A study is made of the dependence of R /sub V/ on the diameter of the grains and the degree and direction of their orientation. It is shown that to find the total extinction it is best to use the relation A /sub V/ = 1.1E(V - K), which holds to an accuracy ≤ 3% in a wide range of parameters of the problem

  13. Working through: in-session processes that promote between-session thoughts and activities.

    Science.gov (United States)

    Owen, Jesse; Quirk, Kelley; Hilsenroth, Mark J; Rodolfa, Emil

    2012-01-01

    This study examined whether clients' ratings of the working alliance as well as their perception of cognitive-behavioral (CB) and psychodynamic-interpersonal (PI) techniques (delivered by therapists who used both) were associated with clients' intersession processes (i.e., their thoughts about therapy and therapeutic activity between sessions). Seventy-five clients who were currently in therapy at a large university counseling center participated in the current study. Multilevel regression analyses demonstrated that alliance and clients' perceptions of their therapists' use of PI techniques were positively associated with clients' general thoughts about therapy between sessions. Also, stronger alliances were associated with more therapeutic activities between sessions and more positive (and less negative) thoughts about therapy between sessions. In addition, clients at later sessions who described their therapists as using more PI techniques also reported engaging in more therapeutic activities between sessions (after controlling for the variance in the other variables, such as use of CB techniques). Clients' perceptions of their therapists' use of CB techniques in the most recent session were not related to thinking about therapy or therapeutic activities after controlling for the variance in the other variables. (c) 2012 APA, all rights reserved.

  14. Cortisol modifies extinction learning of recently acquired fear in men

    Science.gov (United States)

    Hermann, Andrea; Stark, Rudolf; Wolf, Oliver Tobias

    2014-01-01

    Exposure therapy builds on the mechanism of fear extinction leading to decreased fear responses. How the stress hormone cortisol affects brain regions involved in fear extinction in humans is unknown. For this reason, we tested 32 men randomly assigned to receive either 30 mg hydrocortisone or placebo 45 min before fear extinction. In fear acquisition, a picture of a geometrical figure was either partially paired (conditioned stimulus; CS+) or not paired (CS−) with an electrical stimulation (unconditioned stimulus; UCS). In fear extinction, each CS was presented again, but no UCS occurred. Cortisol increased conditioned skin conductance responses in early and late extinction. In early extinction, higher activation towards the CS− than to the CS+ was found in the amygdala, hippocampus and posterior parahippocampal gyrus. This pattern might be associated with the establishment of a new memory trace. In late extinction, the placebo compared with the cortisol group displayed enhanced CS+/CS− differentiation in the amygdala, medial frontal cortex and nucleus accumbens. A change from early deactivation to late activation of the extinction circuit as seen in the placebo group seems to be needed to enhance extinction and to reduce fear. Cortisol appears to interfere with this process thereby impairing extinction of recently acquired conditioned fear. PMID:23945999

  15. A window of vulnerability: impaired fear extinction in adolescence.

    Science.gov (United States)

    Baker, Kathryn D; Den, Miriam L; Graham, Bronwyn M; Richardson, Rick

    2014-09-01

    There have been significant advances made towards understanding the processes mediating extinction of learned fear. However, despite being of clear theoretical and clinical significance, very few studies have examined fear extinction in adolescence, which is often described as a developmental window of vulnerability to psychological disorders. This paper reviews the relatively small body of research examining fear extinction in adolescence. A prominent finding of this work is that adolescents, both humans and rodents, exhibit a marked impairment in extinction relative to both younger (e.g., juvenile) and older (e.g., adult) groups. We then review some potential mechanisms that could produce the striking extinction deficit observed in adolescence. For example, one neurobiological candidate mechanism for impaired extinction in adolescence involves changes in the functional connectivity within the fear extinction circuit, particularly between prefrontal cortical regions and the amygdala. In addition, we review research on emotion regulation and attention processes that suggests that developmental changes in attention bias to threatening cues may be a cognitive mechanism that mediates age-related differences in extinction learning. We also examine how a differential reaction to chronic stress in adolescence impacts upon extinction retention during adolescence as well as in later life. Finally, we consider the findings of several studies illustrating promising approaches that overcome the typically-observed extinction impairments in adolescent rodents and that could be translated to human adolescents. Copyright © 2013 Elsevier Inc. All rights reserved.

  16. Vagus nerve stimulation enhances extinction of conditioned fear and modulates plasticity in the pathway from the infralimbic prefrontal cortex to the amygdala.

    Directory of Open Access Journals (Sweden)

    David Frausto Peña

    2014-09-01

    Full Text Available Fearful experiences can produce long-lasting and debilitating memories. Extinction of the fear response requires consolidation of new memories that compete with fearful associations. Subjects with posttraumatic stress disorder (PTSD show impaired extinction of conditioned fear, which is associated with decreased ventromedial prefrontal cortex (vmPFC control over amygdala activity. Vagus nerve stimulation (VNS enhances memory consolidation in both rats and humans, and pairing VNS with exposure to conditioned cues enhances the consolidation of extinction learning in rats. Here we investigated whether pairing VNS with extinction learning facilitates plasticity between the infralimbic (IL medial prefrontal cortex and the basolateral complex of the amygdala (BLA. Rats were trained on an auditory fear conditioning task, which was followed by a retention test and one day of extinction training. Vagus nerve stimulation or sham-stimulation was administered concurrently with exposure to the fear-conditioned stimulus and retention of fear conditioning was tested again 24 hours later. VNS-treated rats demonstrated a significant reduction in freezing after a single extinction training session similar to animals that received 5x the number of extinction pairings. To study plasticity in the IL-BLA pathway, we recorded evoked field potentials in the BLA in anesthetized animals 24 h after retention testing. Brief burst stimulation in the IL produced LTD in the BLA field response in fear-conditioned and sham-treated animals. In contrast, the same stimulation resulted in potentiation of the IL-BLA pathway in the VNS-treated group. The present findings suggest that VNS promotes plasticity in the IL-BLA pathway to facilitate extinction of conditioned fear responses.

  17. Candesartan ameliorates impaired fear extinction induced by innate immune activation.

    Science.gov (United States)

    Quiñones, María M; Maldonado, Lizette; Velazquez, Bethzaly; Porter, James T

    2016-02-01

    Patients with post-traumatic stress disorder (PTSD) tend to show signs of a relatively increased inflammatory state suggesting that activation of the immune system may contribute to the development of PTSD. In the present study, we tested whether activation of the innate immune system can disrupt acquisition or recall of auditory fear extinction using an animal model of PTSD. Male adolescent rats received auditory fear conditioning in context A. The next day, an intraperitoneal injection of lipopolysaccharide (LPS; 100 μg/kg) prior to auditory fear extinction in context B impaired acquisition and recall of extinction. LPS (100 μg/kg) given after extinction training did not impair extinction recall suggesting that LPS did not affect consolidation of extinction. In contrast to cued fear extinction, contextual fear extinction was not affected by prior injection of LPS (100 μg/kg). Although LPS also reduced locomotion, we could dissociate the effects of LPS on extinction and locomotion by using a lower dose of LPS (50 μg/kg) which impaired locomotion without affecting extinction. In addition, 15 h after an injection of 250 μg/kg LPS in adult rats, extinction learning and recall were impaired without affecting locomotion. A sub-chronic treatment with candesartan, an angiotensin II type 1 receptor blocker, prevented the LPS-induced impairment of extinction in adult rats. Our results demonstrate that activation of the innate immune system can disrupt auditory fear extinction in adolescent and adult animals. These findings also provide direction for clinical studies of novel treatments that modulate the innate immune system for stress-related disorders like PTSD. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Mass extinction efficiency and extinction hygroscopicity of ambient PM2.5 in urban China.

    Science.gov (United States)

    Cheng, Zhen; Ma, Xin; He, Yujie; Jiang, Jingkun; Wang, Xiaoliang; Wang, Yungang; Sheng, Li; Hu, Jiangkai; Yan, Naiqiang

    2017-07-01

    The ambient PM 2.5 pollution problem in China has drawn substantial international attentions. The mass extinction efficiency (MEE) and hygroscopicity factor (f(RH)) of PM 2.5 can be readily applied to study the impacts on atmospheric visibility and climate. The few previous investigations in China only reported results from pilot studies and are lack of spatial representativeness. In this study, hourly average ambient PM 2.5 mass concentration, relative humidity, and atmospheric visibility data from China national air quality and meteorological monitoring networks were retrieved and analyzed. It includes 24 major Chinese cities from nine city-clusters with the period of October 2013 to September 2014. Annual average extinction coefficient in urban China was 759.3±258.3Mm -1 , mainly caused by dry PM 2.5 (305.8.2±131.0Mm -1 ) and its hygroscopicity (414.6±188.1Mm -1 ). High extinction coefficient values were resulted from both high ambient PM 2.5 concentration (68.5±21.7µg/m 3 ) and high relative humidity (69.7±8.6%). The PM 2.5 mass extinction efficiency varied from 2.87 to 6.64m 2 /g with an average of 4.40±0.84m 2 /g. The average extinction hygroscopic factor f(RH=80%) was 2.63±0.45. The levels of PM 2.5 mass extinction efficiency and hygroscopic factor in China were in comparable range with those found in developed countries in spite of the significant diversities among all 24 cities. Our findings help to establish quantitative relationship between ambient extinction coefficient (visual range) and PM 2.5 & relative humidity. It will reduce the uncertainty of extinction coefficient estimation of ambient PM 2.5 in urban China which is essential for the research of haze pollution and climate radiative forcing. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Community stability and selective extinction during the Permian-Triassic mass extinction.

    Science.gov (United States)

    Roopnarine, Peter D; Angielczyk, Kenneth D

    2015-10-02

    The fossil record contains exemplars of extreme biodiversity crises. Here, we examined the stability of terrestrial paleocommunities from South Africa during Earth's most severe mass extinction, the Permian-Triassic. We show that stability depended critically on functional diversity and patterns of guild interaction, regardless of species richness. Paleocommunities exhibited less transient instability—relative to model communities with alternative community organization—and significantly greater probabilities of being locally stable during the mass extinction. Functional patterns that have evolved during an ecosystem's history support significantly more stable communities than hypothetical alternatives. Copyright © 2015, American Association for the Advancement of Science.

  20. Snoring intensity after a first session of soft palate radiofrequency: predictive value of the final result.

    Science.gov (United States)

    Blumen, Marc Bernard; Vezina, Jean Philippe; Bequignon, Emilie; Chabolle, Frederic

    2013-06-01

    To determine whether snoring sound intensity measured after a first soft palate radiofrequency (RF) session for simple snoring helps predict the final result of the treatment. Observational retrospective study. We conducted a retrospective review of 105 subjects presenting with simple snoring or mild sleep apnea. All patients underwent two to three sessions of RF-assisted stiffening of the soft palate. In addition, uvulectomy was performed in case of a long uvula, and two paramedian trenches were created in the presence of palatal webbing. Snoring sound intensity was evaluated by the bed partner after each session. Eighty-six men and 19 women were included in the study. Mean age was 51.7 ± 9.8 years, and mean body mass index was 24.7 ± 4.4 kg/m(2) . The mean apnea/hypopnea index was 6.6 ± 4.2/h. The mean snoring sound intensity, as evaluated on a 10-cm visual analog scale (VAS), decreased from 8.2 ± 1.5 to 3.5 ± 2.2 after all sessions (P snoring sound intensity, using 3 as a threshold. Both groups had similar preoperative characteristics, but the snoring sound intensity was significantly lower after the first session in the group with final score 7 after the first session was associated with a final score Snoring sound intensity after the first RF session helps predict the final outcome of RF-assisted stiffening of the soft palate for simple snoring. Copyright © 2012 The American Laryngological, Rhinological and Otological Society, Inc.

  1. Poster Sessions in Marketing Education: An Empirical Examination

    Science.gov (United States)

    Stegemann, Nicole; Sutton-Brady, Catherine

    2009-01-01

    Poster sessions provide a creative and stimulating alternative to traditional assessment methods in marketing. Poster sessions, as a means of assessment, have long been used in science fields. This article presents the successful implementation of poster sessions as a means of assessment in a postgraduate unit of study. Poster sessions in…

  2. Parameterized Concurrent Multi-Party Session Types

    Directory of Open Access Journals (Sweden)

    Minas Charalambides

    2012-08-01

    Full Text Available Session types have been proposed as a means of statically verifying implementations of communication protocols. Although prior work has been successful in verifying some classes of protocols, it does not cope well with parameterized, multi-actor scenarios with inherent asynchrony. For example, the sliding window protocol is inexpressible in previously proposed session type systems. This paper describes System-A, a new typing language which overcomes many of the expressiveness limitations of prior work. System-A explicitly supports asynchrony and parallelism, as well as multiple forms of parameterization. We define System-A and show how it can be used for the static verification of a large class of asynchronous communication protocols.

  3. Reintroducing resurrected species: selecting DeExtinction candidates.

    Science.gov (United States)

    Seddon, Philip J; Moehrenschlager, Axel; Ewen, John

    2014-03-01

    Technological advances have raised the controversial prospect of resurrecting extinct species. Species DeExtinction should involve more than the production of biological orphans to be scrutinized in the laboratory or zoo. If DeExtinction is to realize its stated goals of deep ecological enrichment, then resurrected animals must be translocated (i.e., released within suitable habitat). Therefore, DeExtinction is a conservation translocation issue and the selection of potential DeExtinction candidates must consider the feasibility and risks associated with reintroduction. The International Union for the Conservation of Nature (IUCN) Guidelines on Reintroductions and Other Conservation Translocations provide a framework for DeExtinction candidate selection. We translate these Guidelines into ten questions to be addressed early on in the selection process to eliminate unsuitable reintroduction candidates. We apply these questions to the thylacine, Yangtze River Dolphin, and Xerces blue butterfly. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Summary of the hadronic weak interaction session

    International Nuclear Information System (INIS)

    Bock, G.; Bryman, D.A.; Numao, T.

    1993-01-01

    The authors summarize and discuss present and future experiments on decays of light mesons and muons that were presented in the Hadronic Weak Interaction working group session of the open-quotes Workshop on Future Directions in Particle and Nuclear Physics at Multi-GeV Hadron Facilities.close quotes Precise measurements and rare-decay searches, which sense mass scales in the 1-1000 TeV region, are discussed in the context of the standard model and beyond

  5. Opening of the 123rd Council session

    CERN Multimedia

    Patrice Loïez

    2002-01-01

    The CERN Council held its 123rd session on 13 December 2002 under the chairmanship of Professor Maurice Bourquin. The election of the next Director General, the Baseline Plan for 2003-2010 and a new status for non-European states were among the items agreed. Photo 01: (left to right) Director-General Prof. Luciano Maiani, President of Council Prof. Maurice Bourquin, and Director of administration Jan van der Boon.

  6. Foundations of Session Types and Behavioural Contracts

    DEFF Research Database (Denmark)

    Huttel, Hans; Lanese, Ivan; T. Vasconcelos, Vasco

    2016-01-01

    Behavioural type systems, usually associated to concurrent or distributed computations, encompass concepts such as interfaces, communication protocols, and contracts, in addition to the traditional input/output operations. The behavioural type of a software component specifies its expected patterns...... of interaction using expressive type languages, so types can be used to determine automatically whether the component interacts correctly with other components. Two related important notions of behavioural types are those of session types and behavioural contracts. This article surveys the main accomplishments...

  7. Overview of the TREC 2014 Session Track

    Science.gov (United States)

    2014-11-01

    wishes to work on the problem of retrieval over sessions. The experimental design of the track was similar to that of the previous three years [5, 6, 1...TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) University of Delaware,Department of Computer & Information...quitting smoking, second effects of quitting smoking, using hypnosis to quit smoking, using the cold turkey method to quit smoking</desc> </topic

  8. Facilitation of fear extinction in phobic participants with a novel cognitive enhancer: a randomized placebo controlled trial of yohimbine augmentation.

    Science.gov (United States)

    Powers, Mark B; Smits, Jasper A J; Otto, Michael W; Sanders, Carlijn; Emmelkamp, Paul M G

    2009-04-01

    Preliminary animal research suggests that yohimbine hydrochloride, a selective competitive alpha2-adrenergic receptor antagonist, accelerates fear extinction and converts ineffective extinction regimens (long intertrial intervals) to effective ones. This randomized placebo controlled study examined the potential exposure enhancing effect of yohimbine hydrochloride in claustrophobic humans. Participants (71% undergraduate students and 29% community volunteers) displaying marked claustrophobic fear (n=24) were treated with 2 1-h in vivo exposure sessions. Participants were randomly allocated to take 10.8mg yohimbine hydrochloride (n=12) or placebo (n=12) prior to each exposure session. Outcome measures included peak fear during a behavioral avoidance task, the Claustrophobia Questionnaire, and the Claustrophobic Concerns Questionnaire. Results showed that both conditions improved significantly at post-treatment with no significant difference between groups. Consistent with prediction the group that took yohimbine hydrochloride prior to exposure sessions showed significantly greater improvement in peak fear at the one-week follow-up behavioral assessment (d=1.68). This was also true across other outcome measures with large to very large effect sizes. These data provide initial support for exposure enhancing effect of single-dose yohimbine hydrochloride in a clinical application.

  9. Noradrenergic Modulation of Fear Conditioning and Extinction.

    Science.gov (United States)

    Giustino, Thomas F; Maren, Stephen

    2018-01-01

    The locus coeruleus norepinephrine (LC-NE) system plays a broad role in learning and memory. Here we begin with an overview of the LC-NE system. We then consider how both direct and indirect manipulations of the LC-NE system affect cued and contextual aversive learning and memory. We propose that NE dynamically modulates Pavlovian conditioning and extinction, either promoting or impairing learning aversive processes under different levels of behavioral arousal. We suggest that under high levels of stress (e.g., during/soon after fear conditioning) the locus coeruleus (LC) promotes cued fear learning by enhancing amygdala function while simultaneously blunting prefrontal function. Under low levels of arousal, the LC promotes PFC function to promote downstream inhibition of the amygdala and foster the extinction of cued fear. Thus, LC-NE action on the medial prefrontal cortex (mPFC) might be described by an inverted-U function such that it can either enhance or hinder learning depending on arousal states. In addition, LC-NE seems to be particularly important for the acquisition, consolidation and extinction of contextual fear memories. This may be due to dense adrenoceptor expression in the hippocampus (HPC) which encodes contextual information, and the ability of NE to regulate long-term potentiation (LTP). Moreover, recent work reveals that the diversity of LC-NE functions in aversive learning and memory are mediated by functionally heterogeneous populations of LC neurons that are defined by their projection targets. Hence, LC-NE function in learning and memory is determined by projection-specific neuromodulation that accompanies various states of behavioral arousal.

  10. Late Pennsylvanian climate changes and palynomorph extinctions

    Energy Technology Data Exchange (ETDEWEB)

    Kosanke, R.M.; Cecil, C.B. [US Geological Survey, Denver, CO (United States)

    1996-01-01

    A major floral change occurs in the Upper Pennsylvanian strata in the Midcontinent, Illinois basin, and in the northern Appalachian basin of eastern United States. Lycospora spp. (derived from arborescent lycopsids) became extinct along with some other palynomorph taxa. This investigation is concerned with the importance of this major floral change. Samples were studied from western Pennsylvania, eastern Ohio, and West Virgina (from a previous study) cover the stratigraphic interval from the Upper Freeport coal bed, uppermost part of the Allegheny Formation, to the Mahoning, Mason, Brush Creek, Wilgus, and Anderson coal beds in the lower part of the Conemaugh Formation. The floral change occurs either at or below the accepted Desmoinesian-Missourian boundary in the Midcontinent and Illinois basin, whereas in the northern Appalachians this change occurs in the lower part of the Conemaugh Formation, between the Mahoning and Brush Creek coal beds, or when the Mason is present, between the Mahoning and Mason coal beds. The first coal bed above the extinction of Lycospora spp. is dominated by the palynomorph taxon Endosporites globiformis which is derived from a heterosporous, herbaceous lycopsid. However, Sigillaria, another arborescent lycopsid, did not become extinct at this time as evidenced by the presence of the palynomorph genus Crassispora which is derived from Sigillaria. The reason for the survival of Sigillaria is now known, but it may have been able to adapt, in a limited fashion, to some sort of specialized microenvironment. The ferns, based on palynomorph occurrence, become numerically more important throughout the balance of the Conemaugh Formation, and dominate the Pittsburgh No. 8 and Pomeroy coal beds in the overlying Monogahela Formation.

  11. Noradrenergic Modulation of Fear Conditioning and Extinction

    Directory of Open Access Journals (Sweden)

    Thomas F. Giustino

    2018-03-01

    Full Text Available The locus coeruleus norepinephrine (LC-NE system plays a broad role in learning and memory. Here we begin with an overview of the LC-NE system. We then consider how both direct and indirect manipulations of the LC-NE system affect cued and contextual aversive learning and memory. We propose that NE dynamically modulates Pavlovian conditioning and extinction, either promoting or impairing learning aversive processes under different levels of behavioral arousal. We suggest that under high levels of stress (e.g., during/soon after fear conditioning the locus coeruleus (LC promotes cued fear learning by enhancing amygdala function while simultaneously blunting prefrontal function. Under low levels of arousal, the LC promotes PFC function to promote downstream inhibition of the amygdala and foster the extinction of cued fear. Thus, LC-NE action on the medial prefrontal cortex (mPFC might be described by an inverted-U function such that it can either enhance or hinder learning depending on arousal states. In addition, LC-NE seems to be particularly important for the acquisition, consolidation and extinction of contextual fear memories. This may be due to dense adrenoceptor expression in the hippocampus (HPC which encodes contextual information, and the ability of NE to regulate long-term potentiation (LTP. Moreover, recent work reveals that the diversity of LC-NE functions in aversive learning and memory are mediated by functionally heterogeneous populations of LC neurons that are defined by their projection targets. Hence, LC-NE function in learning and memory is determined by projection-specific neuromodulation that accompanies various states of behavioral arousal.

  12. Safety Training: scheduled sessions in April

    CERN Multimedia

    DGS Unit

    2011-01-01

    The following training courses are scheduled in April. You can find the full Safety Training programme on the Safety Training online catalogue. If you are interested in attending any of the below courses, please talk to your supervisor, then apply electronically via EDH from the course description pages, by clicking on SIGN-UP. Registration for all courses is always open – sessions for the less-requested courses are organized on a demand-basis only. Depending on the demand, a session will be organised later in the year. Biocell Training 26-APR-11 (08.30 – 10.00) in French 26-APR-11 (10.30 – 12.00) in French Conduite de plates-formes élévatrices mobiles de personnel (PEMP) 28-APR-11 to 29-APR-11 (08.00 – 17.30) in French* Sécurité chimique – Introduction 29-APR-11 (09.00 – 11.30) in French (*) session in French with the possibility of receiving the documentation in English   By Isabelle Cusato (H...

  13. Converging Towards the Optimal Path to Extinction

    Science.gov (United States)

    2011-01-01

    those that occur in pre- vaccine measles [7,43] and multi-strain extinction in diseases such as dengue [44]. Finally, the optimal path method may lead to...SUPPLEMENTARY NOTES The views, opinions and/or findings contained in this report are those of the author(s) and should not contrued as an official Department of...32.36). The views, opinions and/or findings contained in this report are those of the author(s) and should not be construed as an official Department

  14. Rho Ophiuchi Cloud Core Extinction Map

    Science.gov (United States)

    Gibson, D. J.; Rudolph, A.; Barsony, M.

    1997-12-01

    We present an extinction map of a one square degree region ( ~ 2.2pc square) of the core of the star-forming region rho Ophiuchi derived by the method of star counts. Photometry from the near-infrared J, H, and K band images of Barsony et al. (1997) provided the stellar catalog for this study. From this map an estimate of the mass of the region is made and compared with previous estimates from other methods. Reference Barsony, M., Kenyon, S.J., Lada, E.A., & Teuben, P.J. 1997, ApJS, 112, 109

  15. Psychological and neural mechanisms of experimental extinction: a selective review.

    Science.gov (United States)

    Delamater, Andrew R; Westbrook, R Frederick

    2014-02-01

    The present review examines key psychological concepts in the study of experimental extinction and implications these have for an understanding of the underlying neurobiology of extinction learning. We suggest that many of the signature characteristics of extinction learning (spontaneous recovery, renewal, reinstatement, rapid reacquisition) can be accommodated by the standard associative learning theory assumption that extinction results in partial erasure of the original learning together with new inhibitory learning. Moreover, we consider recent behavioral and neural evidence that supports the partial erasure view of extinction, but also note shortcomings in our understanding of extinction circuits as these relate to the negative prediction error concept. Recent work suggests that common prediction error and stimulus-specific prediction error terms both may be required to explain neural plasticity both in acquisition and extinction learning. In addition, we suggest that many issues in the content of extinction learning have not been fully addressed in current research, but that neurobiological approaches should be especially helpful in addressing such issues. These include questions about the nature of extinction learning (excitatory CS-No US, inhibitory CS-US learning, occasion setting processes), especially as this relates to studies of the micro-circuitry of extinction, as well as its representational content (sensory, motivational, response). An additional understudied problem in extinction research is the role played by attention processes and their underlying neural networks, although some research and theory converge on the idea that extinction is accompanied by attention decrements (i.e., habituation-like processes). Copyright © 2013 Elsevier Inc. All rights reserved.

  16. Unbounded autocatalytic growth on diffusive substrate: The extinction transition

    International Nuclear Information System (INIS)

    Moalem, Sasi; Shnerb, Nadav M.

    2007-01-01

    The effect of diffusively correlated spatial fluctuations on the proliferation-extinction transition of autocatalytic agents is investigated numerically. Reactants adaptation to spatio-temporal active regions is shown to lead to proliferation even if the mean field rate equations predict extinction, in agreement with previous theoretical predictions. While in the proliferation phase the system admits a typical time scale that dictates the exponential growth, the extinction times distribution obeys a power law at the parameter region considered

  17. Fear extinction requires infralimbic cortex projections to the basolateral amygdala.

    Science.gov (United States)

    Bloodgood, Daniel W; Sugam, Jonathan A; Holmes, Andrew; Kash, Thomas L

    2018-03-06

    Fear extinction involves the formation of a new memory trace that attenuates fear responses to a conditioned aversive memory, and extinction impairments are implicated in trauma- and stress-related disorders. Previous studies in rodents have found that the infralimbic prefrontal cortex (IL) and its glutamatergic projections to the basolateral amygdala (BLA) and basomedial amygdala (BMA) instruct the formation of fear extinction memories. However, it is unclear whether these pathways are exclusively involved in extinction, or whether other major targets of the IL, such as the nucleus accumbens (NAc) also play a role. To address this outstanding issue, the current study employed a combination of electrophysiological and chemogenetic approaches in mice to interrogate the role of IL-BLA and IL-NAc pathways in extinction. Specifically, we used patch-clamp electrophysiology coupled with retrograde tracing to examine changes in neuronal activity of the IL and prelimbic cortex (PL) projections to both the BLA and NAc following fear extinction. We found that extinction produced a significant increase in the intrinsic excitability of IL-BLA projection neurons, while extinction appeared to reverse fear-induced changes in IL-NAc projection neurons. To establish a causal counterpart to these observations, we then used a pathway-specific Designer Receptors Exclusively Activated by Designer Drugs (DREADD) strategy to selectively inhibit PFC-BLA projection neurons during extinction acquisition. Using this approach, we found that DREADD-mediated inhibition of PFC-BLA neurons during extinction acquisition impaired subsequent extinction retrieval. Taken together, our findings provide further evidence for a critical contribution of the IL-BLA neural circuit to fear extinction.

  18. The risk of extinction - the mutational meltdown or the overpopulation.

    Science.gov (United States)

    Malarz, Krzysztof

    2007-04-01

    The phase diagrams survival-extinction for the Penna model with parameters: (mutations rate)-(birth rate), (mutation rate)-(harmful mutations threshold), (harmful mutation threshold)-(minimal reproduction age) are presented. The extinction phase may be caused by either mutational meltdown or overpopulation. When the Verhulst factor is responsible for removing only newly born babies and does not act on adults the overpopulation is avoided and only genetic factors may lead to species extinction.

  19. The risk of extinction - the mutational meltdown or the overpopulation

    OpenAIRE

    Malarz, K.

    2006-01-01

    The phase diagrams survival-extinction for the Penna model with parameters: (mutations rate)-(birth rate), (mutation rate)-(harmful mutations threshold), (harmful mutation threshold)-(minimal reproduction age) are presented. The extinction phase may be caused by either mutational meltdown or overpopulation. When the Verhulst factor is responsible for removing only newly born babies and does not act on adults the overpopulation is avoided and only genetic factors may lead to species extinction.

  20. Estimating times of extinction in the fossil record

    OpenAIRE

    Wang, Steve C.; Marshall, Charles R.

    2016-01-01

    Because the fossil record is incomplete, the last fossil of a taxon is a biased estimate of its true time of extinction. Numerous methods have been developed in the palaeontology literature for estimating the true time of extinction using ages of fossil specimens. These methods, which typically give a confidence interval for estimating the true time of extinction, differ in the assumptions they make and the nature and amount of data they require. We review the literature on such methods and m...

  1. On the Pleistocene extinctions of Alaskan mammoths and horses

    OpenAIRE

    Solow, Andrew R.; Roberts, David L.; Robbirt, Karen M.

    2006-01-01

    The fossil record has been used to shed light on the late Pleistocene megafaunal extinctions in North America and elsewhere. It is therefore important to account for variability due to the incompleteness of the fossil record and error in dating fossil remains. Here, a joint confidence region for the extinction times of horses and mammoths in Alaska is constructed. The results suggest that a prior claim that the extinction of horses preceded the arrival of humans cannot be made with confidence.

  2. Extinction of megafauna: How could the research get so wrong?

    OpenAIRE

    Nielsen, Ron W

    2013-01-01

    Published evidence for the human-mediated extinction of megafauna is examined and is found to be unsubstantiated. It is shown that the claimed evidence is not based on data describing the growth of human population but on the fabricated data. However, even these fabricated data, which were claimed to support the human-induced extinction of megafauna, contradict this claim. The belief in the human-induced extinction of megafauna appears to be so strong that even contradicting evidence based on...

  3. The Effect of Size and Ecology on Extinction Susceptibility

    Science.gov (United States)

    Huynh, C.; Yuan, A.; Heim, N.; Payne, J.

    2015-12-01

    Although life on Earth first emerged as prokaryotic organisms, it eventually evolved into billions of different species. However, extinctions on Earth, especially the five mass extinctions, have decimated species. So what leads to a species survival or demise during a mass extinction? Are certain species more susceptible to extinctions based on their size and ecology? For this project, we focused on the data of marine animals. To examine the impact of size and ecology on a species's likelihood of survival, we compared the sizes and ecologies of the survivors and victims of the five mass extinctions. The ecology, or life mode, of a genus consists of the combination of tiering, motility, and feeding mechanism. Tiering refers to the animal's typical location in the water column and sediments, motility refers to its ability to move, and feeding mechanism describes the way the organism eats; together, they describe the animal's behavior. We analyzed the effect of ecology on survival using logistic regression, which compares life mode to the success or failure of a genus during each mass extinction interval. For organism size, we found the extinct organisms' mean size (both volume and length) and compared it with the average size of survivors on a graph. Our results show that while surviving genera of mass extinctions tended to be slightly larger than those that went extinct, there was no significant difference. Even though the Permian (Changhsingian) and Triassic (Rhaetian) extinctions had larger surviving species, likewise the difference was small. Ecology had a more obvious impact on the likelihood of survival; fast-moving, predatory pelagic organisms were the most likely to go extinct, while sedentary, infaunal suspension feeders had the greatest chances of survival. Overall, ecology played a greater role than size in determining the survival of a species. With this information, we can use ecology to predict which species would survive future extinctions.

  4. Late Quaternary extinctions: The promise of TAMS 14C dating

    International Nuclear Information System (INIS)

    Martin, P.S.

    1987-01-01

    In the last 30 000 years late Quaternary extinctions eliminated over two-thirds of the large land mammals of America and Australia and most of the endemic land vertebrates on oceanic islands. Specimens of extinct animals yielding too little organic material for measurement in decay counters are suitable for TAMS dating. Initial results support older evidence of an extinction chronology that was catastrophic regionally, transgressive globally, and linked to the spread of prehistoric people. (orig.)

  5. [Findings from Total Colonoscopy in Obstructive Colorectal Cancer Patients Who Underwent Stent Placement as a Bridge to Surgery(BTS)].

    Science.gov (United States)

    Maruo, Hirotoshi; Tsuyuki, Hajime; Kojima, Tadahiro; Koreyasu, Ryohei; Nakamura, Koichi; Higashi, Yukihiro; Shoji, Tsuyoshi; Yamazaki, Masanori; Nishiyama, Raisuke; Ito, Tatsuhiro; Koike, Kota; Ikeda, Takashi; Takayanagi, Yasuhiro; Kubota, Hiroyuki

    2017-11-01

    We clinically investigated 34 patients with obstructive colorectal cancer who underwent placement of a colonic stent as a bridge to surgery(BTS), focusing on endoscopic findings after stent placement.Twenty -nine patients(85.3%)underwent colonoscopy after stent placement, and the entire large intestine could be observed in 28(96.6%).Coexisting lesions were observed in 22(78.6%)of these 28 patients.The lesions comprised adenomatous polyps in 17 patients(60.7%), synchronous colon cancers in 5 patients(17.9%), and obstructive colitis in 3 patients(10.7%), with some overlapping cases.All patients with multiple cancers underwent one-stage surgery, and all lesions were excised at the same time.Colonoscopy after colonic stent placement is important for preoperative diagnosis of coexisting lesions and planning the extent of resection. These considerations support the utility of colonic stenting for BTS.

  6. Extinction in the Galaxy from surface brightnesses of ESO-LV galaxies : Testing "standard" extinction maps

    NARCIS (Netherlands)

    Choloniewski, J.; Valentijn, E. A.

    A new method for the determination of the extinction in the Galaxy is proposed. The method uses surface brightnesses of external galaxies in the B and R-bands. The observational data have been taken from the ESO-LV galaxy catalog. As a first application of our model we derive the ratio of R-band to

  7. Brain structural connectivity and context-dependent extinction memory.

    Science.gov (United States)

    Hermann, Andrea; Stark, Rudolf; Blecker, Carlo R; Milad, Mohammed R; Merz, Christian J

    2017-08-01

    Extinction of conditioned fear represents an important mechanism in the treatment of anxiety disorders. Return of fear after successful extinction or exposure therapy in patients with anxiety disorders might be linked to poor temporal or contextual generalization of extinction due to individual differences in brain structural connectivity. The goal of this magnetic resonance imaging study was therefore to investigate the association of context-dependent extinction recall with brain structural connectivity. Diffusion-tensor imaging was used to determine the fractional anisotropy as a measure of white matter structural integrity of fiber tracts connecting central brain regions of the fear and extinction circuit (uncinate fasciculus, cingulum). Forty-five healthy men participated in a two-day fear conditioning experiment with fear acquisition in context A and extinction learning in context B on the first day. Extinction recall in the extinction context as well as renewal in the acquisition context and a novel context C took place one day later. Renewal of conditioned fear (skin conductance responses) in the acquisition context was associated with higher structural integrity of the hippocampal part of the cingulum. Enhanced structural integrity of the cingulum might be related to stronger hippocampal modulation of the dorsal anterior cingulate cortex, a region important for modulating conditioned fear output by excitatory projections to the amygdala. This finding underpins the crucial role of individual differences in the structural integrity of relevant fiber tracts for context-dependent extinction recall and return of fear after exposure therapy in anxiety disorders. © 2017 Wiley Periodicals, Inc.

  8. On the trap of extinction and its elimination

    International Nuclear Information System (INIS)

    Vitanov, Nikolay K.; Dimitrova, Zlatinka I.; Kantz, Holger

    2006-01-01

    We investigate the dynamics of a system of three interacting populations in presence of extinction and substitution: each population whose number of individuals drops under some threshold value becomes extinct, and it is substituted by another population with different fitness and different coefficients of interaction with the other populations. We study the influence of extinction on the system states, which in the absence of extinction can be fixed points, limit cycles or chaotic attractors of Shilnikov kind. The extinction can destabilize each of these states. We observe two possible kinds of evolution in the destabilized system: (i) it can remain forever in the trap of extinction, i.e., the extinctions and substitutions of populations continue for indefinitely long time or (ii) it can avoid the trap of extinction by means of the substitution, i.e., the fitness and the coefficients of the interactions between the species move the system attractor away from the zone of the threshold values, the extinction stops, and the system settles on a new attractor. The obtained results are discussed from the point of view of products competing for the preference of buyers that can change their opinion

  9. Extinction of Learned Fear Induces Hippocampal Place Cell Remapping

    Science.gov (United States)

    Wang, Melissa E.; Yuan, Robin K.; Keinath, Alexander T.; Ramos Álvarez, Manuel M.

    2015-01-01

    The extinction of learned fear is a hippocampus-dependent process thought to embody new learning rather than erasure of the original fear memory, although it is unknown how these competing contextual memories are represented in the hippocampus. We previously demonstrated that contextual fear conditioning results in hippocampal place cell remapping and long-term stabilization of novel representations. Here we report that extinction learning also induces place cell remapping in C57BL/6 mice. Specifically, we observed cells that preferentially remapped during different stages of learning. While some cells remapped in both fear conditioning and extinction, others responded predominantly during extinction, which may serve to modify previous representations as well as encode new safe associations. Additionally, we found cells that remapped primarily during fear conditioning, which could facilitate reacquisition of the original fear association. Moreover, we also observed cells that were stable throughout learning, which may serve to encode the static aspects of the environment. The short-term remapping observed during extinction was not found in animals that did not undergo fear conditioning, or when extinction was conducted outside of the conditioning context. Finally, conditioning and extinction produced an increase in spike phase locking to the theta and gamma frequencies. However, the degree of remapping seen during conditioning and extinction only correlated with gamma synchronization. Our results suggest that the extinction learning is a complex process that involves both modification of pre-existing memories and formation of new ones, and these traces coexist within the same hippocampal representation. PMID:26085635

  10. Bilateral Alternating Auditory Stimulations Facilitate Fear Extinction and Retrieval

    Directory of Open Access Journals (Sweden)

    Sarah Boukezzi

    2017-06-01

    Full Text Available Disruption of fear conditioning, its extinction and its retrieval are at the core of posttraumatic stress disorder (PTSD. Such deficits, especially fear extinction delay, disappear after alternating bilateral stimulations (BLS during eye movement desensitization and reprocessing (EMDR therapy. An animal model of fear recovery, based on auditory cued fear conditioning and extinction learning, recently showed that BLS facilitate fear extinction and fear extinction retrieval. Our goal was to determine if these previous results found in animals can be reproduced in humans. Twenty-two healthy participants took part in a classical fear conditioning, extinction, and extinction recall paradigm. Behavioral responses (fear expectations as well as psychophysiological measures (skin conductance responses, SCRs were recorded. The results showed a significant fear expectation decrease during fear extinction with BLS. Additionally, SCR for fear extinction retrieval were significantly lower with BLS. Our results demonstrate the importance of BLS to reduce negative emotions, and provide a successful model to further explore the neural mechanisms underlying the sole BLS effect in the EMDR.

  11. Has the Earth's sixth mass extinction already arrived?

    Science.gov (United States)

    Barnosky, Anthony D; Matzke, Nicholas; Tomiya, Susumu; Wogan, Guinevere O U; Swartz, Brian; Quental, Tiago B; Marshall, Charles; McGuire, Jenny L; Lindsey, Emily L; Maguire, Kaitlin C; Mersey, Ben; Ferrer, Elizabeth A

    2011-03-03

    Palaeontologists characterize mass extinctions as times when the Earth loses more than three-quarters of its species in a geologically short interval, as has happened only five times in the past 540 million years or so. Biologists now suggest that a sixth mass extinction may be under way, given the known species losses over the past few centuries and millennia. Here we review how differences between fossil and modern data and the addition of recently available palaeontological information influence our understanding of the current extinction crisis. Our results confirm that current extinction rates are higher than would be expected from the fossil record, highlighting the need for effective conservation measures.

  12. Variation in extinction risk among birds: chance or evolutionary predisposition?

    Science.gov (United States)

    Bennett, P. M.; Owens, I. P. F.

    1997-01-01

    Collar et al. (1994) estimate that of the 9,672 extant species of bird, 1,111 are threatened by extinction. Here, we test whether these threatened species are simply a random sample of birds, or whether there is something about their biology that predisposes them to extinction. We ask three specific questions. First, is extinction risk randomly distributed among families? Second, which families, if any, contain more, or less, threatened species than would be expected by chance? Third, is variation between taxa in extinction risk associated with variation in either body size or fecundity? Extinction risk is not randomly distributed among families. The families which contain significantly more threatened species than expected are the parrots (Psittacidae), pheasants and allies (Phasianidae), albatrosses and allies (Procellariidae), rails (Rallidae), cranes (Gruidae), cracids (Cracidae), megapodes (Megapodidae) and pigeons (Columbidae). The only family which contains significantly fewer threatened species than expected is the woodpeckers (Picidae). Extinction risk is also not distributed randomly with respect to fecundity or body size. Once phylogeny has been controlled for, increases in extinction risk are independently associated with increases in body size and decreases in fecundity. We suggest that this is because low rates of fecundity, which evolved many tens of millions of years ago, predisposed certain lineages to extinction. Low-fecundity populations take longer to recover if they are reduced to small sizes and are, therefore, more likely to go extinct if an external force causes an increase in the rate of mortality, thereby perturbing the natural balance between fecundity and mortality.

  13. IMPACT OF 10 SESSIONS OF WHOLE BODY CRYOSTIMULATION ON AEROBIC AND ANAEROBIC CAPACITY AND ON SELECTED BLOOD COUNT PARAMETERS

    Directory of Open Access Journals (Sweden)

    Tomasz Dybek

    2012-01-01

    Full Text Available The systemic effect of low temperature suggests that sessions in a cryogenic chamber might improve athletes’ capacity as a standard element of training. Therefore the authors decided to evaluate the impact of 10 sessions of whole body cryostimulation (WBCT on aerobic and anaerobic efficiency as well as on selected blood count parameters. The study group included 32 volunteers – 16 women and 16 men. The volunteers underwent 10 sessions of WBCT in a cryogenic chamber. Blood samples (RBC, WBC, PLT, HGB, HCT were taken, and aerobic and anaerobic efficiency and lactate concentration in capillary blood were measured before the first session and one day after the last one. No significant differences were observed in values of aerobic capacity after 10 sessions of WBCT. There was a rising trend in men and a declining trend in women. The lactate concentration did not differ significantly before and after WBCT. A slight rise in aerobic and anaerobic threshold was observed in men, while in women the values slightly fell. The Wingate test showed no significant differences in results before and after cryostimulation. Only the TOBT was significantly shorter in men (6.12±1.49 vs 3.79±1.14 s. The WBCT sessions resulted in a significant rise of the haematological parameters both in women and men, excluding HCT, which showed a statistically insignificant rise. Ten sessions of whole body cryostimulation did not affect aerobic or anaerobic capacity in the tested group, although it improved the blood count parameters.

  14. EXTINCTION OF SPECIES BY PERIODIC COMET SHOWERS

    Energy Technology Data Exchange (ETDEWEB)

    Davis, M.; Hut, P.; Muller, R.A.

    1984-01-01

    A 26-Myr periodicity has recently been seen in the fossil record of extinction in the geological past. At least two of these extinctions are known to be associated with the impact on the Earth of a comet or asteroid with a diameter of a few kilometres. We propose that the periodic events are triggered by an unseen companion to the Sun, travelling in a moderately eccentric orbit, which at its closest approach (perihelion) passes through the 'Oort cloud' of comets which surrounds the Sun. During each passage this unseen solar companion perturbs the orbits of these comets, sending a large number of them (over 1 x 10{sup 9}) into paths which reach the inner Solar System. Several of these hit the Earth, on average, in the following million years. At present the unseen companion should be approximately at its maximum distance from the Sun, {approx}2.4 light yr, and it will present no danger to the Earth until approximately AD 15,000,000.

  15. The Moral Imagination of De-extinction.

    Science.gov (United States)

    Jennings, Bruce

    2017-07-01

    We live amidst the sixth great extinction of life on Earth, and we live under the sign of molecular biology and biotechnology. An ethical maxim that is well-nigh universally acknowledged holds that with great power comes great moral responsibility. For those who accept the science and embrace the responsibility, there are two rather different kinds of moral vision and moral imagination at work. Detractors of biotechnology say that we should see ourselves as creaturely good citizens of the biotic community, accepting and accommodating what evolutionary natural selection has bequeathed to us, warts and all. Boosters of biotechnology say that we should see ourselves as its sovereigns, fashioning better forms of synthetic life and genetically driving evolution in better ways through anthropogenic selection. Faced with biodiversity loss, technology boosters, or eco-modernists, tend to respond by upping the ante on technology in hopes of increasing the benefits and lessening the impact of human relations with nature. The detractors, or eco-communitarians, respond by seeking to restructure the relationship between humans and nature by lowering the profile of human power so as to hear the voice of nonhuman being and better attune ourselves to it. Undergirding both of these moral visions is atonement. As a way of providing atonement, however, de-extinction fails. © 2017 The Hastings Center.

  16. Science observed: The mass-extinction debates

    Science.gov (United States)

    Glen, W.

    The upheaval triggered in 1980 by the Alvarez-Berkeley group impact hypothesis transformed the literature of mass extinctions from an unfocused, sporadic collection of papers that virtually ignored extraterrestrial causes and treated endogenous ones only sparingly better to an integrated, diverse body of literature. Research programs organized seemingly overnight spawned collaborative teams whose members, often from distant, isolated disciplines, redirected their careers in order to address the captivating, high-stakes issues. The initial, generally skeptical, cool reception of the impact hypothesis might have been predicted for any of a number of reasons: such an instantaneous catastrophe contravened earth science's reigning philosophy of uniformitarianism; it was formulated from a form of evidence - siderophile element anomalies - alien to the community charged with its appraisal; it advanced a causal mechanism that was improbable in terms of canonical knowledge; and it was proffered mainly by specialists alien to earth and biological science, especially paleobiology. Early on it became clear that irrespective of which causal hypothesis was chosen, the chosen one would be the strongest predictor of how the chooser would select and apply standards in assessing evidence bearing on all such hypothesis. Less strong correlation also appeared between disciplinary speciality and the assessment of evidence. Such correlations varied with the level of specialization; the most robust correlations appeared in the broadest areas of science practice. The gestalt (mindset) seemingly engendered by the embrace of an extinction hypothesis overrode, or was stronger than, the intellectual predispositions attributable to disciplinary specialty.

  17. Dinosaur extinction: closing the '3 m gap'.

    Science.gov (United States)

    Lyson, Tyler R; Bercovici, Antoine; Chester, Stephen G B; Sargis, Eric J; Pearson, Dean; Joyce, Walter G

    2011-12-23

    Modern debate regarding the extinction of non-avian dinosaurs was ignited by the publication of the Cretaceous-Tertiary (K-T) asteroid impact theory and has seen 30 years of dispute over the position of the stratigraphically youngest in situ dinosaur. A zone devoid of dinosaur fossils reported from the last 3 m of the Upper Cretaceous, coined the '3 m gap', has helped drive controversy. Here, we report the discovery of the stratigraphically youngest in situ dinosaur specimen: a ceratopsian brow horn found in a poorly rooted, silty, mudstone floodplain deposit located no more than 13 cm below the palynologically defined boundary. The K-T boundary is identified using three criteria: (i) decrease in Cretaceous palynomorphs without subsequent recovery, (ii) the existence of a 'fern spike', and (iii) correlation to a nearby stratigraphic section where primary extraterrestrial impact markers are present (e.g. iridium anomaly, spherules, shocked quartz). The in situ specimen demonstrates that a gap devoid of non-avian dinosaur fossils does not exist and is inconsistent with the hypothesis that non-avian dinosaurs were extinct prior to the K-T boundary impact event.

  18. Science observed: The mass-extinction debates

    Science.gov (United States)

    Glen, W.

    1994-01-01

    The upheaval triggered in 1980 by the Alvarez-Berkeley group impact hypothesis transformed the literature of mass extinctions from an unfocused, sporadic collection of papers that virtually ignored extraterrestrial causes and treated endogenous ones only sparingly better to an integrated, diverse body of literature. Research programs organized seemingly overnight spawned collaborative teams whose members, often from distant, isolated disciplines, redirected their careers in order to address the captivating, high-stakes issues. The initial, generally skeptical, cool reception of the impact hypothesis might have been predicted for any of a number of reasons: such an instantaneous catastrophe contravened earth science's reigning philosophy of uniformitarianism; it was formulated from a form of evidence - siderophile element anomalies - alien to the community charged with its appraisal; it advanced a causal mechanism that was improbable in terms of canonical knowledge; and it was proffered mainly by specialists alien to earth and biological science, especially paleobiology. Early on it became clear that irrespective of which causal hypothesis was chosen, the chosen one would be the strongest predictor of how the chooser would select and apply standards in assessing evidence bearing on all such hypothesis. Less strong correlation also appeared between disciplinary speciality and the assessment of evidence. Such correlations varied with the level of specialization; the most robust correlations appeared in the broadest areas of science practice. The gestalt (mindset) seemingly engendered by the embrace of an extinction hypothesis overrode, or was stronger than, the intellectual predispositions attributable to disciplinary specialty.

  19. Atmospheric extinction in simulation tools for solar tower plants

    Science.gov (United States)

    Hanrieder, Natalie; Wilbert, Stefan; Schroedter-Homscheidt, Marion; Schnell, Franziska; Guevara, Diana Mancera; Buck, Reiner; Giuliano, Stefano; Pitz-Paal, Robert

    2017-06-01

    Atmospheric extinction causes significant radiation losses between the heliostat field and the receiver in a solar tower plants. These losses vary with site and time. State of the art is that in ray-tracing and plant optimization tools, atmospheric extinction is included by choosing between few constant standard atmospheric conditions. Even though some tools allow the consideration of site and time dependent extinction data, such data sets are nearly never available. This paper summarizes and compares the most common model equations implemented in several ray-tracing tools. There are already several methods developed and published to measure extinction on-site. An overview of the existing methods is also given here. Ray-tracing simulations of one exemplary tower plant at the Plataforma Solar de Almería (PSA) are presented to estimate the plant yield deviations between simulations using standard model equations instead of extinction time series. For PSA, the effect of atmospheric extinction accounts for losses between 1.6 and 7 %. This range is caused by considering overload dumping or not. Applying standard clear or hazy model equations instead of extinction time series lead to an underestimation of the annual plant yield at PSA. The discussion of the effect of extinction in tower plants has to include overload dumping. Situations in which overload dumping occurs are mostly connected to high radiation levels and low atmospheric extinction. Therefore it can be recommended that project developers should consider site and time dependent extinction data especially on hazy sites. A reduced uncertainty of the plant yield prediction can significantly reduce costs due to smaller risk margins for financing and EPCs. The generation of extinction data for several locations in form of representative yearly time series or geographical maps should be further elaborated.

  20. 3,4-Methylenedioxymethamphetamine facilitates fear extinction learning.

    Science.gov (United States)

    Young, M B; Andero, R; Ressler, K J; Howell, L L

    2015-09-15

    Acutely administered 3,4-methylenedioxymethamphetamine (MDMA, 'ecstasy') has been proposed to have long-term positive effects on post-traumatic stress disorder (PTSD) symptoms when combined with psychotherapy. No preclinical data support a mechanistic basis for these claims. Given the persistent nature of psychotherapeutic gains facilitated by MDMA, we hypothesized that MDMA improves fear extinction learning, a key process in exposure-based therapies for PTSD. In these experiments, mice were first exposed to cued fear conditioning and treated with drug vehicle or MDMA before extinction training 2 days later. MDMA was administered systemically and also directly targeted to brain structures known to contribute to extinction. In addition to behavioral measures of extinction, changes in mRNA levels of brain-derived neurotrophic factor (Bdnf) and Fos were measured after MDMA treatment and extinction. MDMA (7.8 mg kg(-1)) persistently and robustly enhanced long-term extinction when administered before extinction training. MDMA increased the expression of Fos in the amygdala and medial prefrontal cortex (mPFC), whereas increases in Bdnf expression were observed only in the amygdala after extinction training. Extinction enhancements were recapitulated when MDMA (1 μg) was infused directly into the basolateral complex of the amygdala (BLA), and enhancement was abolished when BDNF signaling was inhibited before extinction. These findings suggest that MDMA enhances fear memory extinction through a BDNF-dependent mechanism, and that MDMA may be a useful adjunct to exposure-based therapies for PTSD and other anxiety disorders characterized by altered fear learning.

  1. Summary of Session 4 "Beam Energy"

    CERN Document Server

    Siemko, A

    2011-01-01

    In this session, the possible scenarios for the beam energy in the LHC 2011 run were discussed. The benefits for the physics reach for physics operations at s larger than 7 TeV were reviewed. The main goal was, however, to establish the necessary information for a sound risk analysis by assessing the probability of thermal runaway and evaluating the consequences of a hypothetical incident. A new technique to improve the knowledge of joint resistances of the cooper busbars and therefore the reliability of the risk analysis has also been discussed.

  2. Moderator report on workshop session 3

    International Nuclear Information System (INIS)

    Isaacs, T.

    2004-01-01

    While much in Stakeholder confidence work is focused on the periods of project conceptualization, siting, and development, eventually a successful waste programme will result in a set of facilities with visual, aesthetic, and other physical impacts on the host community. This most interesting and interactive session explored both the artistic and aesthetic aspects of the waste management process and the relationship among the stakeholders, particularly the affected local communities and those who might help develop both the products and processes associated with implementation. Two insightful presentations were made, followed by a lively panel discussion and interactions with the broader FSC participants. (author)

  3. Parallel Monitors for Self-adaptive Sessions

    Directory of Open Access Journals (Sweden)

    Mario Coppo

    2016-06-01

    Full Text Available The paper presents a data-driven model of self-adaptivity for multiparty sessions. System choreography is prescribed by a global type. Participants are incarnated by processes associated with monitors, which control their behaviour. Each participant can access and modify a set of global data, which are able to trigger adaptations in the presence of critical changes of values. The use of the parallel composition for building global types, monitors and processes enables a significant degree of flexibility: an adaptation step can dynamically reconfigure a set of participants only, without altering the remaining participants, even if the two groups communicate.

  4. Session of International Committee on radiological safety

    International Nuclear Information System (INIS)

    Il'in, L.A.; Aleksakhin, R.M.

    1998-01-01

    Information of the work of ICRP Session held in September, 1997 in Oxford (Great Britain) is presented. Results of activities of the committees of ICRP are discussed. Committee 1 deals with the problems of genetic predisposition to carcinoma and multifactor diseases. Activities of Committee 2 directed to the development of radiation dose limits. Function of Committee 3 devotes to the solution of radiation protection problems in medicine. Main attention of Committee 4 was paid to the development of approaches to radiation protection in case of chronic irradiation [ru

  5. Late Pennsylvanian climate changes and palynomorph extinctions

    Science.gov (United States)

    Kosanke, R.M.; Cecil, C.B.

    1996-01-01

    A major floral change occurs in the Upper Pennsylvanian strata in the Midcontinent, Illinois basin, and in the northern Appalachian basin of eastern United States. Lycospora spp. (derived from arborescent lycopsids) became extinct along with some other palynomorph taxa. This investigation is concerned with the importance of this major floral change. Samples were studied from western Pennsylvania, eastern Ohio, and West Virginia (from a previous study) cover the stratigraphic interval from the Upper Freeport coal bed, uppermost part of the Allegheny Formation, to the Mahoning, Mason, Brush Creek, Wilgus, and Anderson coal beds in the lower part of the Conemaugh Formation. The floral change occurs either at or below the accepted Desmoinesian-Missourian boundary in the Midcontinent and Illinois basin, whereas in the northern Appalachians this change occurs in the lower part of the Conemaugh Formation, between the Mahoning and Brush Creek coal beds, or when the Mason is present, between the Mahoning and Mason coal beds. With the advent of late Middle Pennsylvanian time, the climate began to change from wet tropical to seasonal tropical. The Middle-Upper Pennsylvanian boundary is the culmination of this drying trend, which was marked by reduction of available water. The peat swamps are interpreted as having changed from the domed type of bog to the planar type under these circumstances. Thus, in general, the coals of the Conemaugh Formation are characteristically much thinner than those of the Allegheny Formation. This was caused by a number of factors including reduced or more seasonal rainfall, decline of arborescent lycopsids, and the increased dominance of herbaceous and fern plants. As a result, there are fewer minable coal beds in the Conemaugh Formation. The first coal bed above the extinction of Lycospora spp. is dominated by the palynomorph taxon Endosporites globiformis which is derived from a heterosporous, herbaceous lycopsid. However, Sigillaria, another

  6. Enhanced extinction of electromagnetic radiation by metal-coated fibers

    Energy Technology Data Exchange (ETDEWEB)

    Kleiman, Moshe [Israel Institute for Biological Research, P.O. Box 19, Ness-Ziona 74100 (Israel)]. E-mail: moshe@iibr.gov.il; Gurwich, Ioseph [Life Science Research Israel, Ltd., P.O. Box 139, Ness-Ziona 70451 (Israel); Shiloah, Nir [Israel Institute for Biological Research, P.O. Box 19, Ness-Ziona 74100 (Israel)

    2007-07-15

    The scattering properties of metal-coated fibers are studied. It is shown that an optimal thickness of the metal layer exists, for which the extinction efficiency can significantly exceed the extinction efficiency of uncoated homogeneous metal fibers of identical size. At the same time the scattering efficiency of coated fibers remains lower than that of the homogeneous ones.

  7. Relating plant height to demographic rates and extinction vulnerability

    NARCIS (Netherlands)

    Jonge, de Melinda M.J.; Hilbers, Jelle P.; Jongejans, Eelke; Ozinga, Wim A.; Hendriks, A.J.; Huijbregts, Mark A.J.

    2018-01-01

    To prioritize conservation efforts, it is important to know which plant species are most vulnerable to extinction. Intrinsic extinction vulnerabilities depend on demographic parameters, but for many species these demographic parameters are lacking. Body size has been successfully used as proxy of

  8. DUST EXTINCTION IN NGC-4594, THE SOMBRERO GALAXY

    NARCIS (Netherlands)

    KNAPEN, JH; HES, R; BECKMAN, JE; PELETIER, RF

    We have studied the extinction law in the well-defined dust lane of the Sombrero galaxy, NGC4594. In the R,I,J,H, and K bands we find good agreement between values for the extinction ratios A-lambda/A(v) in NGC4594 and those reported for our own Galaxy. We can explain the apparently somewhat lower

  9. Ultraviolet extinction in M-supergiant circumstellar envelopes

    International Nuclear Information System (INIS)

    Buss, R.H. Jr.; Snow, T.P. Jr.

    1986-01-01

    Using International Ultraviolet (IUS) archival low-dispersion spectra, ultraviolet spectral extinctions were derived for the circumstellar envelopes of two M supergiants: HD 60414 and HD 213310. The observed stellar systems belong to a class of widely-separated spectroscopic binaries that are called VV Cephei stars. The total extinction was calculated by dividing the reddened fluxes with unreddened comparison fluxes of similar stars (g B2.5 for HD 213310 and a normalized s+B3 for HD 60414) from the reference atlas. After substracting the interstellar extinctions, which were estimated from the E(B-V) reddening of nearby stars, the resultant circumstellar extinctions were normalized at about 3.5 inverse microns. Not only is the 2175 A extinction bump absent in the circumstellar extinctions, but the far-ultraviolet extinction rise is also absent. The rather flat, ultraviolet extinction curves were interpreted as signatures of a population of noncarbonaceous, oxygen-rich grains with diameters larger than the longest observed wavelength

  10. d-Cycloserine reduces context specificity of sexual extinction learning

    NARCIS (Netherlands)

    Brom, Mirte; Laan, Ellen; Everaerd, Walter; Spinhoven, Philip; Trimbos, Baptist; Both, Stephanie

    2015-01-01

    d-Cycloserine (DCS) enhances extinction processes in animals. Although classical conditioning is hypothesized to play a pivotal role in the aetiology of appetitive motivation problems, no research has been conducted on the effect of DCS on the reduction of context specificity of extinction in human

  11. Three-Component Dust Models for Interstellar Extinction C ...

    Indian Academy of Sciences (India)

    Abstract. Interstellar extinction curves obtained from the 'extinction without standard' method were used to constrain the dust characteristics in the mean ISM (RV = 3.1), along the lines of sight through a high latitude diffuse molecular cloud towards HD 210121 (RV = 2.1) and in a dense interstellar environment towards the ...

  12. A comprehensive quantitative assessment of bird extinction risk in Brazil.

    Directory of Open Access Journals (Sweden)

    Nathália Machado

    Full Text Available In an effort to avoid species loss, scientists have focused their efforts on the mechanisms making some species more prone to extinction than others. However, species show different responses to threats given their evolutionary history, behavior, and intrinsic biological features. We used bird biological features and external threats to (1 understand the multiple pathways driving Brazilian bird species to extinction, (2 to investigate if and how extinction risk is geographically structured, and (3 to quantify how much diversity is currently represented inside protected areas. We modeled the extinction risk of 1557 birds using classification trees and evaluated the relative contribution of each biological feature and external threat in predicting extinction risk. We also quantified the proportion of species and their geographic range currently protected by the network of Brazilian protected areas. The optimal classification tree showed different pathways to bird extinction. Habitat conversion was the most important predictor driving extinction risk though other variables, such as geographic range size, type of habitat, hunting or trapping and trophic guild, were also relevant in our models. Species under higher extinction risk were concentrated mainly in the Cerrado Biodiversity Hotspot and were not quite represented inside protected areas, neither in richness nor range. Predictive models could assist conservation actions, and this study could contribute by highlighting the importance of natural history and ecology in these actions.

  13. THE NEAR EXTINCTION OF THE IGBO LANGUAGE Toni-Duruaku ...

    African Journals Online (AJOL)

    the Igbo language to revitalize its use so that it does not go extinct. Keywords: Language, Culture, Thinking English, Extinction, Igbo Language .... method of teaching. Consequences a). Loss of Value It has earlier been averred in this paper that language is part of culture. The way a person behaves is a manifestation of the ...

  14. Environmental determinants of extinction selectivity in the fossil record.

    Science.gov (United States)

    Peters, Shanan E

    2008-07-31

    The causes of mass extinctions and the nature of biological selectivity during extinction events remain central questions in palaeobiology. Although many different environmental perturbations have been invoked as extinction mechanisms, it has long been recognized that fluctuations in sea level coincide with many episodes of biotic turnover. Recent work supports the hypothesis that changes in the areas of epicontinental seas have influenced the macroevolution of marine animals, but the extent to which differential environmental turnover has contributed to extinction selectivity remains unknown. Here I use a new compilation of the temporal durations of sedimentary rock packages to show that carbonate and terrigenous clastic marine shelf environments have different spatio-temporal dynamics and that these dynamics predict patterns of genus-level extinction, extinction selectivity and diversity among Sepkoski's Palaeozoic and modern evolutionary faunae. These results do not preclude a role for biological interactions or unusual physical events as drivers of macroevolution, but they do suggest that the turnover of marine shelf habitats and correlated environmental changes have been consistent determinants of extinction, extinction selectivity and the shifting composition of the marine biota during the Phanerozoic eon.

  15. Deepened Extinction following Compound Stimulus Presentation: Noradrenergic Modulation

    Science.gov (United States)

    Janak, Patricia H.; Corbit, Laura H.

    2011-01-01

    Behavioral extinction is an active form of new learning involving the prediction of nonreward where reward has previously been present. The expression of extinction learning can be disrupted by the presentation of reward itself or reward-predictive stimuli (reinstatement) as well as the passage of time (spontaneous recovery) or contextual changes…

  16. Porous and Fluffy Grains in the Regions of Anomalous Extinction

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... It has long been established that the ratio of total to selective extinction is anomalously large (≥ 5) in certain regions of the interstellar medium. In these regions of anomalous extinction the dust grains are likely to be irregular in shape and fluffy in structure. Using discrete dipole approximation (DDA) we ...

  17. Modeling aerosols and extinction in the marine atmospheric boundary layer

    NARCIS (Netherlands)

    Leeuw, G.; Eijk, A.M.; Noordhuis, G.R.

    1993-01-01

    An analysis is presented of aerosol particle size distributions measured over the North Atlantic and extinction coefficients derived from these data. Two empirical models, an aerosol model and an extinction model, are formulated in terms of simple meteorological parameters (wind speed, relative

  18. Safety Training: scheduled sessions in May

    CERN Multimedia

    Isabelle Cusato (HSE Unit)

    2011-01-01

    The following training courses are scheduled in March. You can find the full Safety Training programme on the Safety Training online catalogue. If you are interested in attending any of the below courses, please talk to your supervisor, then apply electronically via EDH from the course description pages, by clicking on SIGN-UP. Registration for all courses is always open – sessions for the less-requested courses are organized on a demand-basis only. Depending on the demand, a session will be organised later in the year.   Biocell Training 10-MAY-11 (08.30 – 10.00) in French 10-MAY-11 (10.30 – 12.00) in French 12-MAY-11 (08.30 – 10.00) in English 12-MAY-11 (10.30 – 12.00) in English 19-MAY-11 (08.30 – 10.00) in French 19-MAY-11 (10.30 – 12.00) in French 24-MAY-11 (08.30 – 10.00) in English 24-MAY-11 (10.30 – 12.00) in English   Champs Magnétiques 13-MAY-11 (09.30 – 11.30) in French...

  19. Safety Training: scheduled sessions in March

    CERN Multimedia

    DGS Unit

    2011-01-01

    The following training courses are scheduled in March. You can find the full Safety Training programme on the Safety Training online catalogue. If you are interested in attending any of the below courses, please talk to your supervisor, then apply electronically via EDH from the course description pages, by clicking on SIGN-UP. Registration for all courses is always open – sessions for the less-requested courses are organized on a demand-basis only. Depending on the demand, a session will be organised later in the year. Biocell Training 08-MAR-11 (08.30 – 10.00) in English 08-MAR-11 (10.30 – 12.00) in French 15-MAR-11 (08.30 – 10.00) in French 15-MAR-11 (10.30 – 12.00) in French 17-MAR-11 (08.30 – 10.00) in English 17-MAR-11 (10.30 – 12.00) in English 22-MAR-11 (08.30 – 10.00) in French 22-MAR-11 (10.30 – 12.00) in French 24-MAR-11 (08.30 – 10.00) in French 24-MAR-11 (10.30 – 12.00) in French 29-MAR...

  20. Aspen Global Change Institute Summer Science Sessions

    Energy Technology Data Exchange (ETDEWEB)

    Katzenberger, John; Kaye, Jack A

    2006-10-01

    The Aspen Global Change Institute (AGCI) successfully organized and convened six interdisciplinary meetings over the course of award NNG04GA21G. The topics of the meetings were consistent with a range of issues, goals and objectives as described within the NASA Earth Science Enterprise Strategic Plan and more broadly by the US Global Change Research Program/Our Changing Planet, the more recent Climate Change Program Strategic Plan and the NSF Pathways report. The meetings were chaired by two or more leaders from within the disciplinary focus of each session. 222 scholars for a total of 1097 participants-days were convened under the auspices of this award. The overall goal of each AGCI session is to further the understanding of Earth system science and global environmental change through interdisciplinary dialog. The format and structure of the meetings allows for presentation by each participant, in-depth discussion by the whole group, and smaller working group and synthesis activities. The size of the group is important in terms of the group dynamics and interaction, and the ability for each participant's work to be adequately presented and discussed within the duration of the meeting, while still allowing time for synthesis

  1. Round table discussion during session 2

    International Nuclear Information System (INIS)

    Mays, C.

    2004-01-01

    The round table discussions of the second session of the FSC Belgium Workshop addressed the following questions: - Do local stakeholders have, internally or externally, all the expertise they need in order to address the issues raised by radioactive waste management projects? - Do institutional stakeholders have all the expertise they need to take local impacts into account? - What kinds of expert input are sought and attained by the different stakeholders? - Were any formal methods used to aid local partnerships perform technology assessments? Or other types of assessment? - How to maintain the knowledge and expertise achieved by the stakeholders? Discussion took place after the plenary presentations, at tables grouping Belgian stakeholders and FSC delegates. As in Session I, most of the round table discussion focussed specifically on the experience of the local partnerships. Many insights were shared about the nature and role of expertise in complex decision making. They are summarised below, on the basis of the feedback provided to the plenary by each round table. Some of these insights can be generalised to other contexts. All in all, a profile emerged of the local partnerships as a unique and effective tool to deal with knowledge issues in managing risk. (author)

  2. Unpaired shocks during extinction weaken the contextual renewal of a conditioned discrimination

    NARCIS (Netherlands)

    Vervliet, B.; Vansteenwegen, D.; Hermans, D.

    2010-01-01

    Extinction is generally more fragile than conditioning, as illustrated by the contextual renewal effect. The traditional extinction procedure entails isolated presentations of the conditioned stimulus. Extinction may be boosted by adding isolated presentations of the unconditioned stimulus, as this

  3. How to detect and visualize extinction thresholds for structured PVA models

    NARCIS (Netherlands)

    Hildenbrandt, H.; Grimm, V.

    2006-01-01

    An extinction threshold is a population size below which extinction risk increases to beyond critical values. However, detecting extinction thresholds for structured population models is not straightforward because many different population structures may correspond to the same population size.

  4. Extinction of Harrington's mountain goat

    Energy Technology Data Exchange (ETDEWEB)

    Mead, J.I.; Martin, P.S.; Euler, R.C.; Long, A.; Jull, A.J.T.; Toolin, L.J.; Donahue, D.J.; Linick, T.W.

    1986-02-01

    Keratinous horn sheaths of the extinct Harrington's mountain goat, Oreamnos harringtoni, were recovered at or near the surface of dry caves of the Grand Canyon, Arizona. Twenty-three separate specimens from two caves were dated nondestructively by the tandem accelerator mass spectrometer (TAMS). Both the TAMS and the conventional dates indicate that Harrington's mountain goat occupied the Grand Canyon for at least 19,000 years prior to becoming extinct by 11,160 +/- 125 radiocarbon years before present. The youngest average radiocarbon dates on Shasta ground sloths, Nothrotheriops shastensis, from the region are not significantly younger than those on extinct mountain goats. Rather than sequential extinction with Harrington's mountain goat disappearing from the Grand Canyon before the ground sloths, as one might predict in view of evidence of climatic warming at the time, the losses were concurrent. Both extinctions coincide with the regional arrival of Clovis hunters.

  5. Theoretical investigation of the extinction coefficient of magnetic fluid

    Energy Technology Data Exchange (ETDEWEB)

    Fang Xiaopeng; Xuan Yimin, E-mail: ymxuan@mail.njust.edu.cn; Li Qiang [Nanjing University of Science and Technology, School of Energy and Power Engineering (China)

    2013-05-15

    A new theoretical approach for calculating the extinction coefficient of magnetic fluid is proposed, which is based on molecular dynamics (MD) simulation and T-matrix method. By means of this approach, the influence of particle diameter, particle volume fraction, and external magnetic filed on the extinction coefficient of magnetic fluid is investigated. The results show that the extinction coefficient of the magnetic fluid linearly increases with increase in the particle volume fraction. For a given particle volume fraction, the extinction coefficient increases with increase in the particle diameter which varies from 5 to 20 nm. When a uniform external magnetic filed is applied to the magnetic fluid, the extinction coefficient of the magnetic fluid presents an anisotropic feature. These results agree well with the reported experimental results. The proposed approach is applicable to investigating the optical properties of magnetic fluids.

  6. Habitat destruction and the extinction debt revisited

    Energy Technology Data Exchange (ETDEWEB)

    Loehle, C.

    1996-02-01

    A very important analysis of the problem of habitat destruction concluded that such destruction may lead to an extinction debt, which is the irreversible loss of species following a prolonged transient or delay. An error in interpretation of this model led the authors to apply the results to all types of habitat destruction, but in fact the model applies only to an across-the-board decrease in fecundity, not to disturbances. For repeated, spatially random disturbance, a different model applies. For habitat destruction on regional scales (reduction in ecosystem area without disturbance in remnant areas), one must, in contrast, apply species-area relations based on the distribution of different habitat types (e.g., elevational and rainfall gradients, physiographic and edaphic variability). The error in interpretation of the basic model is presented, followed by clarification of model usage and development of a new model that applies to disturbance events.

  7. Compact plasmonic memristor with high extinction efficiency

    Science.gov (United States)

    Tian, Ye; Jiang, Lianjun; Zhang, Xuejun; Zhang, Guangfu

    2017-10-01

    Here we present a plasmonic memristor operated at the telecommunication wavelength with compact size (0.61 μm), and high extinction efficiency (4.6 dB/μm). The plasmonic memristor consists of a triangle-shaped metal taper mounted on the top of a Si waveguide with rational doping in the area below the apex of the taper. This device can achieve vertical coupling of light energy from the Si waveguide to the plasmonic region and at the same time concentrates the plasmon to the apex of the metal taper. Moreover, the area with concentrated plasmon is overlap with that where the memristive behavior occurs due to the formation/removal of the metallic nanofilament. As a result, the highly distinct transmission induced by the switching of the plasmonic memristor can be achieved due to the maximized interaction between the plasmon and the filament.

  8. Molar extinction coefficients of some fatty acids

    DEFF Research Database (Denmark)

    Sandhu, G.K.; Singh, K.; Lark, B.S.

    2002-01-01

    The attenuation of gamma rays in some fatty acids, viz. formic acid (CH2O2), acetic acid (C2H4O2), propionic acid (C3H6O2), butyric acid (C4H8O2), n-hexanoic acid (C6H12O2), n-caprylic acid (C8H16O2), lauric acid (C12H24O2), myristic acid (C14H28O2), palmitic acid (C16H32O2), oleic acid (C18H34O2......) and stearic acid (C18H36O2), has been measured at the photon energies 81, 356, 511, 662, 1173 and 1332 keV. Experimental values for the molar extinction coefficient, the effective atomic number and the electron density have been derived and compared with theoretical calculations. There is good agreement...

  9. 78 FR 53497 - Commercial Space Transportation Advisory Committee; Closed Session

    Science.gov (United States)

    2013-08-29

    ... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Commercial Space Transportation... Commercial Space Transportation Advisory Committee Special Closed Session. SUMMARY: Pursuant to Section 10(a...), notice is hereby given of a special closed session of the Commercial Space Transportation Advisory...

  10. Music Education and Music Therapy. Introduction to Plenary Session 3

    DEFF Research Database (Denmark)

    Bonde, Lars Ole

    2002-01-01

    Chairman's introduction to plenary session on the relationship between music therapy and music pedagogics......Chairman's introduction to plenary session on the relationship between music therapy and music pedagogics...

  11. Evolution of dust extinction curves in galaxy simulation

    Science.gov (United States)

    Hou, Kuan-Chou; Hirashita, Hiroyuki; Nagamine, Kentaro; Aoyama, Shohei; Shimizu, Ikkoh

    2017-07-01

    To understand the evolution of extinction curve, we calculate the dust evolution in a galaxy using smoothed particle hydrodynamic simulations incorporating stellar dust production, dust destruction in supernova shocks, grain growth by accretion and coagulation, and grain disruption by shattering. The dust species are separated into carbonaceous dust and silicate. The evolution of grain size distribution is considered by dividing grain population into large and small grains, which allows us to estimate extinction curves. We examine the dependence of extinction curves on the position, gas density and metallicity in the galaxy, and find that extinction curves are flat at t ≲ 0.3 Gyr because stellar dust production dominates the total dust abundance. The 2175 Å bump and far-ultraviolet (FUV) rise become prominent after dust growth by accretion. At t ≳ 3 Gyr, shattering works efficiently in the outer disc and low-density regions, so extinction curves show a very strong 2175 Å bump and steep FUV rise. The extinction curves at t ≳ 3 Gyr are consistent with the Milky Way extinction curve, which implies that we successfully included the necessary dust processes in the model. The outer disc component caused by stellar feedback has an extinction curve with a weaker 2175 Å bump and flatter FUV slope. The strong contribution of carbonaceous dust tends to underproduce the FUV rise in the Small Magellanic Cloud extinction curve, which supports selective loss of small carbonaceous dust in the galaxy. The snapshot at young ages also explains the extinction curves in high-redshift quasars.

  12. Reconstructing past species assemblages reveals the changing patterns and drivers of extinction through time

    OpenAIRE

    Bromham, Lindell; Lanfear, Robert; Cassey, Phillip; Gibb, Gillian; Cardillo, Marcel

    2012-01-01

    Predicting future species extinctions from patterns of past extinctions or current threat status relies on the assumption that the taxonomic and biological selectivity of extinction is consistent through time. If the driving forces of extinction change through time, this assumption may be unrealistic. Testing the consistency of extinction patterns between the past and the present has been difficult, because the phylogenetically explicit methods used to model present-day extinction risk typica...

  13. Accelerated modern human?induced species losses: Entering the sixth mass extinction

    OpenAIRE

    Ceballos, Gerardo; Ehrlich, Paul R.; Barnosky, Anthony D.; Garc?a, Andr?s; Pringle, Robert M.; Palmer, Todd M.

    2015-01-01

    The oft-repeated claim that Earth?s biota is entering a sixth ?mass extinction? depends on clearly demonstrating that current extinction rates are far above the ?background? rates prevailing between the five previous mass extinctions. Earlier estimates of extinction rates have been criticized for using assumptions that might overestimate the severity of the extinction crisis. We assess, using extremely conservative assumptions, whether human activities are causing a mass extinction. First, we...

  14. The metabotropic glutamate 5 receptor modulates extinction and reinstatement of methamphetamine-seeking in mice.

    Directory of Open Access Journals (Sweden)

    Rose Chesworth

    Full Text Available Methamphetamine (METH is a highly addictive psychostimulant with no therapeutics registered to assist addicts in discontinuing use. Glutamatergic dysfunction has been implicated in the development and maintenance of addiction. We sought to assess the involvement of the metabotropic glutamate 5 receptor (mGlu5 in behaviours relevant to METH addiction because this receptor has been implicated in the actions of other drugs of abuse, including alcohol, cocaine and opiates. mGlu5 knockout (KO mice were tested in intravenous self-administration, conditioned place preference and locomotor sensitization. Self-administration of sucrose was used to assess the response of KO mice to a natural reward. Acquisition and maintenance of self-administration, as well as the motivation to self-administer METH was intact in mGlu5 KO mice. Importantly, mGlu5 KO mice required more extinction sessions to extinguish the operant response for METH, and exhibited an enhanced propensity to reinstate operant responding following exposure to drug-associated cues. This phenotype was not present when KO mice were tested in an equivalent paradigm assessing operant responding for sucrose. Development of conditioned place preference and locomotor sensitization were intact in KO mice; however, conditioned hyperactivity to the context previously paired with drug was elevated in KO mice. These data demonstrate a role for mGlu5 in the extinction and reinstatement of METH-seeking, and suggests a role for mGlu5 in regulating contextual salience.

  15. Trajectories of Late Permian – Jurassic radiolarian extinction rates: no evidence for an end-Triassic mass extinction

    Directory of Open Access Journals (Sweden)

    W. Kiessling

    2011-02-01

    Full Text Available The hypothesis that ocean acidification was a proximate trigger of the marine end-Triassic mass extinction rests on the assumption that taxa that strongly invest in the secretion of calcium-carbonate skeletons were significantly more affected by the crisis than other taxa. An argument against this hypothesis is the great extinction toll of radiolarians that has been reported from work on local sections. Radiolarians have siliceous tests and thus should be less affected by ocean acidification. We compiled taxonomically vetted occurrences of late Permian and Mesozoic radiolarians and analyzed extinction dynamics of radiolarian genera. Although extinction rates were high at the end of the Triassic, there is no evidence for a mass extinction in radiolarians but rather significantly higher background extinction in the Triassic than in the Jurassic. Although the causes for this decline in background extinction levels remain unclear, the lack of a major evolutionary response to the end-Triassic event, gives support for the hypothesis that ocean acidification was involved in the dramatic extinctions of many calcifying taxa. doi:10.1002/mmng.201000017

  16. APACHE II SCORING SYSTEM AND ITS MODIFICATION FOR THE ASSESSMENT OF DISEASE SEVERITY IN CHILDREN WHO UNDERWENT POLYCHEMOTHERAPY

    Directory of Open Access Journals (Sweden)

    А. V. Sotnikov

    2014-01-01

    Full Text Available Short-term disease prognosis should be considered for the appropriate treatment policy based on the assessment of disease severity in patients with acute disease. The adequate assessment of disease severity and prognosis allows the indications for transferring patients to the resuscitation and intensive care department to be defined more precisely. Disease severity of patients who underwent polychemotherapy was assessed using APACHE II scoring system.

  17. Atrioventricular septal defect (AVSD) : A study of 219 patients who underwent surgery for AVSD at Rikshospitalet from 1979 to 1999

    OpenAIRE

    Skraastad, Ingrid Birthe Bendixen; Skraastad, Berit Kristine

    2010-01-01

    Background: The present study evaluates 219 consecutive patients that underwent surgical repair for AVSD in a long term follow-up. Methods: The patients had a surgical correction for AVSD at Rikshospitalet from January 1979 to December 1999. The follow-up was closed in January 2009. AVSD with additional defects and syndromes were included. Results: Forty-two patients died during the observational period. Early mortality was 12.8% and late mortality was 6.4%. Early mortality declined f...

  18. Comparison of libido, Female Sexual Function Index, and Arizona scores in women who underwent laparoscopic or conventional abdominal hysterectomy

    Science.gov (United States)

    Kayataş, Semra; Özkaya, Enis; Api, Murat; Çıkman, Seyhan; Gürbüz, Ayşen; Eser, Ahmet

    2017-01-01

    Objective: The aim of the present study was to compare female sexual function between women who underwent conventional abdominal or laparoscopic hysterectomy. Materials and Methods: Seventy-seven women who were scheduled to undergo hysterectomy without oophorectomy for benign gynecologic conditions were included in the study. The women were assigned to laparoscopic or open abdominal hysterectomy according to the surgeons preference. Women with endometriosis and symptomatic prolapsus were excluded. Female sexual function scores were obtained before and six months after the operation from each participant by using validated questionnaires. Results: Pre- and postoperative scores of three different quationnaires were found as comparable in the group that underwent laparoscopic hysterectomy (p>0.05). Scores were also found as comparable in the group that underwent laparotomic hysterectomy (p>0.05). Pre- and postoperative values were compared between the two groups and revealed similar results with regard to all three scores (p>0.05). Conclusion: Our data showed comparable pre- and the postoperative scores for the two different hysterectomy techniques. The two groups were also found to have similar pre- and postoperative score values. PMID:28913149

  19. Vaginal and pelvic recurrence rates based on vaginal cuff length in patients with cervical cancer who underwent radical hysterectomies.

    Science.gov (United States)

    Kim, K; Cho, S Y; Park, S I; Kim, B J; Kim, M H; Choi, S C; Ryu, S Y; Lee, E D

    2011-09-01

    The objective of this study was to determine the association of vaginal cuff length (VCL) with vaginal and pelvic recurrence rates in patients with cervical cancer who underwent radical hysterectomies. The clinicopathologic characteristics were collected from the medical records of 280 patients with cervical cancer who underwent radical hysterectomies. The association of VCL with 3-year vaginal and pelvic recurrence rates was determined using a Z-test. The association of VCL with other clinicopathologic characteristics was also determined. The VCL was not associated with 3-year vaginal and pelvic recurrence rates. The 3-year vaginal recurrence rate was 0%-2% and the 3-year pelvic recurrence rate was 7%-8%, independent of VCL. The VCL and the age of patients had an inverse relationship. However, the VCL was not associated with histologic type, FIGO stage, clinical tumor size, tumor size in the surgical specimen, depth of invasion, lymphovascular space invasion, parametrial involvement, lymph node involvement, and adjuvant therapy. One-hundred ninety of 280 patients (68%) underwent adjuvant therapies following radical hysterectomies. Although it is limited by the high rate of adjuvant therapy, the current study suggested that the VCL following radical hysterectomy in patients with cervical cancer was not associated with vaginal and pelvic recurrence rates. Copyright © 2011 Elsevier Ltd. All rights reserved.

  20. 76 FR 41278 - Cargo Security Risk Reduction; Public Listening Sessions

    Science.gov (United States)

    2011-07-13

    ... Listening Sessions AGENCY: Coast Guard, DHS. ACTION: Notice of meetings. SUMMARY: The Coast Guard's Office of Port and Facility Activities (CG- 544) is sponsoring information and listening sessions in St... listening sessions described in this notice. Agenda of Public Meeting The Coast Guard is holding listening...

  1. Asynchronous Session Types – Exceptions and Multiparty Interactions

    DEFF Research Database (Denmark)

    Carbone, Marco; Yoshida, Nobuko; Honda, Kohei

    2009-01-01

    Session types are a formalism for structuring communication based on the notion of session: the structure of a conversation is abstracted as a type which is then used as a basis of validating programs through an associated type discipline. While standard session types have proven to be able to ca...

  2. Bringing golf into sport psychology sessions through technology ...

    African Journals Online (AJOL)

    Bringing golf into sport psychology sessions through technology (video footage) ... sessions through technology (video footage). L Human, D Kriek, T Bezuidenhout ... psychology sessions informed by narrative practice with the six golfers respectively, during which the identified material from Stage 2 was discussed. During ...

  3. 2004 scientific forum - Session 2 summary

    International Nuclear Information System (INIS)

    Shephard, L.

    2004-01-01

    The growth of nuclear power, while providing many benefits, has also contributed to an increasing global challenge over safe and secure waste and spent fuel management. Over the past fifty years, the world has come to better understand the strong interplay between all elements of the nuclear fuel cycle, global economics, and global security. The nuclear fuel cycle can no longer be managed as a simple sequence of technological, economic and political challenges. Rather it must be managed as a system of strongly related issues - waste and spent fuel management cannot be relegated to the back-end of the fuel cycle as only a disposal or storage issue. There exists a wealth of success and experience with waste and spent fuel management that can be forged together with a global systems perspective to lay the framework for the future. The three keynote speakers and four panellists for session 2 (waste and spent fuel management issues) of the 2004 Scientific Forum reviewed related experience to date, including approaches from direct disposal to the closed cycle. Regarding the latter, reprocessing of irradiated power reactor fuel was noted to be a mature, commercially available technology. Experience to date has demonstrated that commercial reprocessing can be compatible with security and non-proliferation requirements. There has also been a continuing reduction in the volume of waste arising from reprocessing. This trend will continue with the implementation of improved technology and operating practices. R and D programmes to study the partitioning and transmutation of environmentally significant radionuclides are being pursued to further enhance the effectiveness of waste minimization programmes. Regarding direct disposal, session 2 participants described significant progress to date. As described in the Director General's statement to the 48th session of the General Conference, Finland, the USA, and Sweden have all moved forward with their geologic disposal programmes

  4. Spontaneous recovery from extinction in the infant rat.

    Science.gov (United States)

    Revillo, D A; Paglini, M G; Arias, C

    2014-11-01

    Within the Pavlovian conditioning framework, extinction is a procedure in which, after conditioning, the conditioned stimulus (CS) is repeatedly presented without the unconditioned stimulus (US). During this procedure the conditioned response (CR) is gradually attenuated. It has been suggested that extinction during the early stages of ontogeny is a qualitatively different process from extinction in adulthood: during infancy, extinction may result in erasure of the memory, while during adulthood extinction involves new learning. This conclusion was supported by studies showing that renewal, reinstatement or spontaneous recovery procedures were not effective during infancy for recovering the CR once it had been extinguished. These studies used the freezing response as the only behavioral index, although some recent evidence indicates that the absence of freezing after conditioning or after extinction does not necessarily imply a deficit in memory, and that other behavioral indexes may be more sensitive to detecting conditioning effects. The goal of the present study was to analyze extinction in preweanling rats by examining the possibility of the spontaneous recovery of a conditioned fear response, measured through a different set of mutually-exclusive behaviors that constitute an exhaustive ethogram, and including control groups (Experiment 1: US-Only and CS-Only; Experiment 2: US-Only, CS-Only and Unpaired) in order to examine whether non-associative learning may explain quantitative or qualitative changes in the frequency of specific responses during extinction or recovery. Extinction produced changes in the expression of freezing, grooming and exploration, and the clearest evidence of spontaneous recovery came from the analysis of freezing behavior. The pattern of behavior observed during extinction is compatible with theoretical approaches which consider different dynamic behavioral systems, and it also fit in well with a molar approach to the analysis of

  5. Estimating the normal background rate of species extinction.

    Science.gov (United States)

    De Vos, Jurriaan M; Joppa, Lucas N; Gittleman, John L; Stephens, Patrick R; Pimm, Stuart L

    2015-04-01

    A key measure of humanity's global impact is by how much it has increased species extinction rates. Familiar statements are that these are 100-1000 times pre-human or background extinction levels. Estimating recent rates is straightforward, but establishing a background rate for comparison is not. Previous researchers chose an approximate benchmark of 1 extinction per million species per year (E/MSY). We explored disparate lines of evidence that suggest a substantially lower estimate. Fossil data yield direct estimates of extinction rates, but they are temporally coarse, mostly limited to marine hard-bodied taxa, and generally involve genera not species. Based on these data, typical background loss is 0.01 genera per million genera per year. Molecular phylogenies are available for more taxa and ecosystems, but it is debated whether they can be used to estimate separately speciation and extinction rates. We selected data to address known concerns and used them to determine median extinction estimates from statistical distributions of probable values for terrestrial plants and animals. We then created simulations to explore effects of violating model assumptions. Finally, we compiled estimates of diversification-the difference between speciation and extinction rates for different taxa. Median estimates of extinction rates ranged from 0.023 to 0.135 E/MSY. Simulation results suggested over- and under-estimation of extinction from individual phylogenies partially canceled each other out when large sets of phylogenies were analyzed. There was no evidence for recent and widespread pre-human overall declines in diversity. This implies that average extinction rates are less than average diversification rates. Median diversification rates were 0.05-0.2 new species per million species per year. On the basis of these results, we concluded that typical rates of background extinction may be closer to 0.1 E/MSY. Thus, current extinction rates are 1,000 times higher than natural

  6. Analysis of autonomic modulation after an acute session of resistance exercise at different intensities in chronic obstructive pulmonary disease patients.

    Science.gov (United States)

    Nicolino, Juliana; Ramos, Dionei; Leite, Marceli Rocha; Rodrigues, Fernanda Maria Machado; de Alencar Silva, Bruna Spolador; Tacao, Guilherme Yassuyuki; de Toledo, Alessandra Choqueta; Vanderlei, Luiz Carlos Marques; Ramos, Ercy Mara Cipulo

    2015-01-01

    Physical exercises are employed as part of the treatment of patients with chronic obstructive pulmonary disease (COPD); however information regarding cardiac autonomic modulation after an acute session of resistance exercise (RE) is unknown. The aim of this study was to evaluate the cardiac autonomic modulation, via heart rate variability after an acute session of RE applied at different intensities in COPD patients. Twelve COPD patients underwent an acute session of RE with an intensity of 60% and another of 90% of the one repetition maximum test. For analysis of autonomic modulation, heart rate was recorded beat-by-beat for 20 minutes at rest and after the training session. Heart rate variability indexes were obtained in the time and frequency domains for the assessment of autonomic modulation. Regardless of exercise intensity, RE acute sessions influenced the autonomic modulation when the recovery period was compared with the baseline. An increase in standard deviation of normal to normal RR intervals was observed throughout recovery time after the RE, as compared to baseline in both protocols: 60% and 90% of the one repetition maximum test. The spectral component of low frequency index (ms) was higher throughout recovery when compared to baseline in both protocols. The same was also observed in the spectral component of high frequency index (ms) for the protocols of 60% and 90%. RE sessions impact on the autonomic modulation of COPD patients by promoting differences in the recovery period compared to baseline, regardless of the intensity of the exercise performed.

  7. Working through: In-Session Processes that Promote Between-Session Thoughts and Activities

    Science.gov (United States)

    Owen, Jesse; Quirk, Kelley; Hilsenroth, Mark J.; Rodolfa, Emil

    2012-01-01

    This study examined whether clients' ratings of the working alliance as well as their perception of cognitive-behavioral (CB) and psychodynamic-interpersonal (PI) techniques (delivered by therapists who used both) were associated with clients' intersession processes (i.e., their thoughts about therapy and therapeutic activity between sessions).…

  8. Session A5: hadron spectroscopy, experimental

    International Nuclear Information System (INIS)

    Ozaki, S.

    1978-01-01

    Reports 55 contubutions made by mini-rapporteurs and individual contributors are assembled. It is clear, from the contributions made to this session, that there has been steady progress in solving the problem of the hadron spectroscopy of the old style. The picture on the scalar mesons has become clearer. Among the vector meson group, we started to understand Q mesons, though the situation with A 1 is still not clear. Mesons with higher spin have been found and, in some cases, confirmed. In a sense, the jigsaw puzzle on the mesons is gradually being completed while more complex features are found. The same can be said on the baryons. An active study is in progress in the experiment on the exotic states such as narrow baryonium and dibaryon states. However, owing to the difficulty of such experiments and interpretation of the data, a definitive result is yet to come. 94 references

  9. Report on session 1984-1985

    International Nuclear Information System (INIS)

    Wilson, H.W.

    1985-01-01

    During this session the centre changed ownership, so that as from 1st October 1985 it will be operated by Edinburgh, Glasgow and Strathclyde Universities. Aberdeen and St. Andrews are associate members for access to the isotope geology facilities. Other Universities will use the centre on a commercial basis. The research activities are summarized; these are divided into reactor related activities with brief outlines of the projects undertaken in radiochemistry and physics, health physics and nuclear medicine and engineering. The number of analyses undertaken in isotope Geology increased to over 4,000. Sulphur isotope techniques were introduced during the year. The work at the NERC radiocarbon laboratory is also described. The teaching aspects of the reactor and its operation during the year are recorded. There were no problems with the reactor operation and it achieved its highest energy output of 232.5MWH. (U.K.)

  10. Instruments for documentation of music therapy sessions

    DEFF Research Database (Denmark)

    Ridder, Hanne Mette Ochsner

    to the most basic information about what happened in each session, and graphs provide an overview of the music therapy course over time. In the presentation I will give examples of this instrument and show how the documentation of the process is included in a larger research study with focus on measuring...... the effect of music therapy in an RCT (Ridder & Stige 2010). My purpose of presenting the instrument, and show case examples where it has been used, is to inspire clinicians and researchers to develop similar instruments; meaningful not only to clinical practice, but also for documentation and large scale...... research. References: Ridder, H.M. & Stige, B. (2011). A joint research protocol for music therapy in dementia care. Conference Issue; World Congress in Music Therapy, Seoul 2011. Music Therapy Today, 9(1), 90-91....

  11. Session Report - F. Boydon (UK-ONR)

    International Nuclear Information System (INIS)

    Boydon, Frans

    2014-01-01

    This report summarises presentations nationally (France, Switzerland, Canada) and identify specific areas of interest followed by general comments observations out of all the presentations in this session about the challenges to the Regulator and the Implementer preparing for construction and operation of geological repositories: stepwise phased approach, early engagement with regulators, the need for regulators to be clear about their expectations including any R and D requirements especially on how to deal with ageing effects, information management both in terms of volume and format, importance of the organisational structure of the license applicant (this structure is likely to evolve with time from that of a design organisation to one of a constructor/contractor to an operator (and constructor combined)), importance for regulators to consider in advance what the challenges of a DGR are and to implement suitable recruitment and training processes for its staff

  12. Ecole de Physique des Houches: session 96

    CERN Document Server

    Huard, Benjamin; Schoelkopf, Robert; Cugliandolo, Leticia F; Quantum Machines : Measurement and Control of Engineered Quantum Systems

    2014-01-01

    This book gathers the lecture notes of courses given at the 2011 summer school in theoretical physics in Les Houches, France, Session XCVI. What is a quantum machine? Can we say that lasers and transistors are quantum machines? After all, physicists advertise these devices as the two main spin-offs of the understanding of quantum mechanical phenomena. However, while quantum mechanics must be used to predict the wavelength of a laser and the operation voltage of a transistor, it does not intervene at the level of the signals processed by these systems. Signals involve macroscopic collective variables like voltages and currents in a circuit or the amplitude of the oscillating electric field in an electromagnetic cavity resonator. In a true quantum machine, the signal collective variables, which both inform the outside on the state of the machine and receive controlling instructions, must themselves be treated as quantum operators, just as the position of the electron in a hydrogen atom. Quantum superconducting...

  13. Precise subtyping for synchronous multiparty sessions

    Directory of Open Access Journals (Sweden)

    Mariangiola Dezani-Ciancaglini

    2016-02-01

    Full Text Available The notion of subtyping has gained an important role both in theoretical and applicative domains: in lambda and concurrent calculi as well as in programming languages. The soundness and the completeness, together referred to as the preciseness of subtyping, can be considered from two different points of view: operational and denotational. The former preciseness has been recently developed with respect to type safety, i.e. the safe replacement of a term of a smaller type when a term of a bigger type is expected. The latter preciseness is based on the denotation of a type which is a mathematical object that describes the meaning of the type in accordance with the denotations of other expressions from the language. The result of this paper is the operational and denotational preciseness of the subtyping for a synchronous multiparty session calculus. The novelty of this paper is the introduction of characteristic global types to prove the operational completeness.

  14. Tying Extinction Events to Comet Impacts Large Enough to Cause an Extinction in Themselves.

    Science.gov (United States)

    Burgener, J. A.

    2017-12-01

    Comets over 35 km in size impacting Earth will create vast fireballs, and will boil large parts of the oceans, causing extinction events in themselves. They will likely provide enough energy to shatter the crust and eject large masses of molten rock from the mantle, forming traps. Traps are clearly associated with extinction events, but are not expected to cause extinctions. While Chicxulub is recognized to have occurred at the time of the K/Pg boundary layer, it is recognized as being too small in itself to cause an extinction. Are large comet impacts likely? The Kuiper belt has more than 100,000 objects over 100 km in diameter and millions over 10 km. Typically their orbits are less stable than asteroid orbits due to large bodies such as Pluto moving through the belt. The asteroid belt has only 10,000 objects over 10 km diameter. Comet impacts should be more common than asteroid impacts, yet none of the recognized craters are expected to be due to comets. There are many features on Earth that are poorly explained by Plate Tectonics that would be well explained if they were considered to be comet impact craters. A consideration of the Black Sea and the Tarim Basin will show that impact interpretations are a better fit than the present Plate Tectonics' explanations. Both basins are in the midst of mountain building from plate collisions, but are themselves not being disturbed by the plate collisions. Both are ellipses angled at 23.4 degrees to the equator, matching the angle expected for a low angle impact from a comet traveling in the ecliptic. Both are too deep at 15 km depths to be standard oceans (typically 5 km deep). Both are filled with horizontal layers of sediments, undisturbed by the mountain building occurring at the edges. Both have thin crusts and high Moho boundaries. Both have thin lithosphere. Yet both show GPS movement of the land around them moving away from them, as though they were much thicker and stronger than the surrounding land. The Tarim

  15. Size distribution of interstellar particles. III. Peculiar extinctions and normal infrared extinction

    International Nuclear Information System (INIS)

    Mathis, J.S.; Wallenhorst, S.G.

    1981-01-01

    The effect of changing the upper and lower size limits of a distribution of bare graphite and silicate particles with n(a)αa/sup -q/ is investigated. Mathis, Rumpl, and Nordsieck showed that the normal extinction is matched very well by having the small-size cutoff, a/sub -/, roughly-equal0.005 or 0.01 μm, and the large size a/sub +/, about 0.25 μm, and q = 3.5 for both substances. We consider the progressively peculiar extinctions exhibited by the well-observed stars, sigma Sco, rho Oph, and theta 1 Ori C, with values of R/sub v/[equivalentA/sub v//E(B--V)] of 3.4, 4.4, and 5.5 compared to the normal 3.1. Two (sigma Sco, rho Oph) are in a neutral dense cloud; theta 1 Ori C is in the Orion Nebula. We find that sigma Sco has a normal graphite distribution but has had its small silicate particles removed, so that a/sub -/(sil)roughly-equal0.04 μm if q = 3.5, or q(sil) = 2.6 if the size limits are fixed. However, the upper size limit on silicates remains normal. In rho Oph, the graphite is still normal, but both a/sub -/(sil) and a/sub +/(sil) are increased, to about 0.04 μm and 0.4 or 0.5 μm, respectively, if q = 3.5, or q(sil)roughly-equal1.3 if the size limits are fixed. In theta 1 Ori, the small limit on graphite has increased to about 0.04 μm, or q(gra)roughly-equal3, while the silicates are about like those in rho Oph. The calculated lambda2175 bump is broader than the observed, but normal foreground extinction probably contributes appreciably to the observed bump. The absolute amount of extinction per H atom for rho Oph is not explained. The column density of H is so large that systematic effects might be present. Very large graphite particles (a>3 μm) are required to ''hide'' the graphite without overly affecting the visual extinction, but a normal (small) graphite size distribution is required by the lambda2175 bump. We feel that it is unlikely that such a bimodal distribution exists

  16. Detailed session outputs by the groups

    International Nuclear Information System (INIS)

    2008-01-01

    Session 1 (What are we trying to look at and when should we do it?) discussed the following points: - What are the key characteristics of safety culture that we should look at as nuclear regulators? - Should/can the regulator look at attitudes, values and behaviours as well as processes and documents? - Can safety culture be regarded as a separate topic or is it best considered as part of other regulatory areas e.g. safety management? - When do we/should we gather information about safety culture? Session 2a (How do we gather and interpret data? Tools, methods, resources and competencies needed to gather safety culture data) discussed the following points: - What methods can/do we use to gather data on licensee safety culture? What are their advantages and disadvantages? - How do we ensure that regulatory staff carrying out safety culture interventions are competent to do so - and what knowledge/skills and training are needed? - Who should gather safety culture data for regulatory use - regulators? Specialist contractors or others? Session 2b (How to gather and interpret the data? How to interpret data and codify it, qualitative versus quantitative data) discussed the following points: - How do we make a judgement on licensee safety culture? Do we have adequate indicators/criteria? - Can we meaningfully extrapolate from a finding on one part of plant to the whole organisation? If not, what should we conclude? - Is it meaningful to rate/score licensee safety culture numerically? - Are safety cultures methods mature enough to numerically score? What are the risks of this approach? Session 3 (How can we use the data?) discussed the following points: - How can safety culture data collection be built into existing regulatory activities? - How do we engage with licensees so that they accept and act on safety culture findings? - How do we expect licensees to respond to issues raised? - Is interaction with licensees on safety culture compatible with other regulatory

  17. ON GALACTIC DENSITY MODELING IN THE PRESENCE OF DUST EXTINCTION

    International Nuclear Information System (INIS)

    Bovy, Jo; Rix, Hans-Walter; Schlafly, Edward F.; Green, Gregory M.; Finkbeiner, Douglas P.

    2016-01-01

    Inferences about the spatial density or phase-space structure of stellar populations in the Milky Way require a precise determination of the effective survey volume. The volume observed by surveys such as Gaia or near-infrared spectroscopic surveys, which have good coverage of the Galactic midplane region, is highly complex because of the abundant small-scale structure in the three-dimensional interstellar dust extinction. We introduce a novel framework for analyzing the importance of small-scale structure in the extinction. This formalism demonstrates that the spatially complex effect of extinction on the selection function of a pencil-beam or contiguous sky survey is equivalent to a low-pass filtering of the extinction-affected selection function with the smooth density field. We find that the angular resolution of current 3D extinction maps is sufficient for analyzing Gaia sub-samples of millions of stars. However, the current distance resolution is inadequate and needs to be improved by an order of magnitude, especially in the inner Galaxy. We also present a practical and efficient method for properly taking the effect of extinction into account in analyses of Galactic structure through an effective selection function. We illustrate its use with the selection function of red-clump stars in APOGEE using and comparing a variety of current 3D extinction maps

  18. Empirical relationship of ultraviolet extinction and the interstellar diffuse bands

    International Nuclear Information System (INIS)

    Wu, C.; York, D.G.; Snow, T.P.

    1981-01-01

    New ultraviolet colors are presented for 110 hot stars. These data are combined with infrared colors and diffuse-band measurements to study the relationship of diffuse interstellar bands (lambdalambda4430, 5780, 6284) to the overall extinction curve. Equivalent widths of lambdalambda5780 and 6284 are not well correlated with infrared, visible, or ultraviolet extinction measurements for stars in our sample. The central depth of lambda4430 is well correlated with visible and infrared extinction, but less well correlated with UV extinction at 1800 A. lambda4430 is strongly correlated with the strength of the 2200-A bump. Our data suggest that if small grains account for the general rise in UV extinction, the diffuse bands are not formed in these grains. lambda4430 may well arise in large grains and/or in the material responsible for the 2200-A bump. Correlations with UV extinctions derived by other authors are discussed in detail. It is suggested that definitions of extinction parameters and band shapes, as well as selection effects in small samples of stars, may still compromise conclusions based on correlation studies such as we are attempting

  19. LINE DERIVED INFRARED EXTINCTION TOWARD THE GALACTIC CENTER

    International Nuclear Information System (INIS)

    Fritz, T. K.; Gillessen, S.; Dodds-Eden, K.; Lutz, D.; Genzel, R.; Raab, W.; Ott, T.; Pfuhl, O.; Eisenhauer, F.; Yusef-Zadeh, F.

    2011-01-01

    We derive the extinction curve toward the Galactic center (GC) from 1 to 19 μm. We use hydrogen emission lines of the minispiral observed by ISO-SWS and SINFONI. The extinction-free flux reference is the 2 cm continuum emission observed by the Very Large Array. Toward the inner 14'' x 20'', we find an extinction of A 2.166μm = 2.62 ± 0.11, with a power-law slope of α = -2.11 ± 0.06 shortward of 2.8 μm, consistent with the average near-infrared slope from the recent literature. At longer wavelengths, however, we find that the extinction is grayer than shortward of 2.8 μm. We find that it is not possible to fit the observed extinction curve with a dust model consisting of pure carbonaceous and silicate grains only, and the addition of composite particles, including ices, is needed to explain the observations. Combining a distance-dependent extinction with our distance-independent extinction, we derive the distance to the GC to be R 0 = 7.94 ± 0.65 kpc. Toward Sgr A* (r H = 4.21 ± 0.10, A Ks = 2.42 ± 0.10, and A L' = 1.09 ± 0.13.

  20. ON GALACTIC DENSITY MODELING IN THE PRESENCE OF DUST EXTINCTION

    Energy Technology Data Exchange (ETDEWEB)

    Bovy, Jo [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON, M5S 3H4 (Canada); Rix, Hans-Walter; Schlafly, Edward F. [Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany); Green, Gregory M.; Finkbeiner, Douglas P., E-mail: bovy@astro.utoronto.ca [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    2016-02-20

    Inferences about the spatial density or phase-space structure of stellar populations in the Milky Way require a precise determination of the effective survey volume. The volume observed by surveys such as Gaia or near-infrared spectroscopic surveys, which have good coverage of the Galactic midplane region, is highly complex because of the abundant small-scale structure in the three-dimensional interstellar dust extinction. We introduce a novel framework for analyzing the importance of small-scale structure in the extinction. This formalism demonstrates that the spatially complex effect of extinction on the selection function of a pencil-beam or contiguous sky survey is equivalent to a low-pass filtering of the extinction-affected selection function with the smooth density field. We find that the angular resolution of current 3D extinction maps is sufficient for analyzing Gaia sub-samples of millions of stars. However, the current distance resolution is inadequate and needs to be improved by an order of magnitude, especially in the inner Galaxy. We also present a practical and efficient method for properly taking the effect of extinction into account in analyses of Galactic structure through an effective selection function. We illustrate its use with the selection function of red-clump stars in APOGEE using and comparing a variety of current 3D extinction maps.

  1. MODELING GALACTIC EXTINCTION WITH DUST AND 'REAL' POLYCYCLIC AROMATIC HYDROCARBONS

    International Nuclear Information System (INIS)

    Mulas, Giacomo; Casu, Silvia; Cecchi-Pestellini, Cesare; Zonca, Alberto

    2013-01-01

    We investigate the remarkable apparent variety of galactic extinction curves by modeling extinction profiles with core-mantle grains and a collection of single polycyclic aromatic hydrocarbons. Our aim is to translate a synthetic description of dust into physically well-grounded building blocks through the analysis of a statistically relevant sample of different extinction curves. All different flavors of observed extinction curves, ranging from the average galactic extinction curve to virtually 'bumpless' profiles, can be described by the present model. We prove that a mixture of a relatively small number (54 species in 4 charge states each) of polycyclic aromatic hydrocarbons can reproduce the features of the extinction curve in the ultraviolet, dismissing an old objection to the contribution of polycyclic aromatic hydrocarbons to the interstellar extinction curve. Despite the large number of free parameters (at most the 54 × 4 column densities of each species in each ionization state included in the molecular ensemble plus the 9 parameters defining the physical properties of classical particles), we can strongly constrain some physically relevant properties such as the total number of C atoms in all species and the mean charge of the mixture. Such properties are found to be largely independent of the adopted dust model whose variation provides effects that are orthogonal to those brought about by the molecular component. Finally, the fitting procedure, together with some physical sense, suggests (but does not require) the presence of an additional component of chemically different very small carbonaceous grains.

  2. Sexual selection affects local extinction and turnover in bird communities

    Science.gov (United States)

    Doherty, P.F.; Sorci, G.; Royle, J. Andrew; Hines, J.E.; Nichols, J.D.; Boulinier, T.

    2003-01-01

    Predicting extinction risks has become a central goal for conservation and evolutionary biologists interested in population and community dynamics. Several factors have been put forward to explain risks of extinction, including ecological and life history characteristics of individuals. For instance, factors that affect the balance between natality and mortality can have profound effects on population persistence. Sexual selection has been identified as one such factor. Populations under strong sexual selection experience a number of costs ranging from increased predation and parasitism to enhanced sensitivity to environmental and demographic stochasticity. These findings have led to the prediction that local extinction rates should be higher for species/populations with intense sexual selection. We tested this prediction by analyzing the dynamics of natural bird communities at a continental scale over a period of 21 years (1975-1996), using relevant statistical tools. In agreement with the theoretical prediction, we found that sexual selection increased risks of local extinction (dichromatic birds had on average a 23% higher local extinction rate than monochromatic species). However, despite higher local extinction probabilities, the number of dichromatic species did not decrease over the period considered in this study. This pattern was caused by higher local turnover rates of dichromatic species, resulting in relatively stable communities for both groups of species. Our results suggest that these communities function as metacommunities, with frequent local extinctions followed by colonization. Anthropogenic factors impeding dispersal might therefore have a significant impact on the global persistence of sexually selected species.

  3. Extinction and spontaneous recovery of spatial behavior in pigeons.

    Science.gov (United States)

    Leising, Kenneth J; Wong, Jared; Blaisdell, Aaron P

    2015-10-01

    We investigated extinction and spontaneous recovery of spatial associations using a landmark-based appetitive search task in a touchscreen preparation with pigeons. Four visual landmarks (A, B, C, and D) were separately established as signals of a hidden reinforced target among an 8 × 7 array of potential target locations. The target was located above landmarks (LM) A and C and below B and D. After conditioning, A and B were extinguished. Responding to A and C was assessed on probe tests 2 days following extinction, whereas, B and D were tested 14 days after extinction. We observed spontaneous recovery from spatial extinction following a 14-day, but not a 2-day, postextinction retention interval. Furthermore, by plotting the spatial distribution of responding across the X and Y axes during testing, we found that spontaneous recovery of responding to the target in our task was due to enhanced spatial control (i.e., a change in the overall distribution of responses) following the long delay to testing. These results add spatial extinction and spontaneous recovery to the list of findings supporting the assertion that extinction involves new learning that attenuates the originally acquired response, and that original learning of the spatial relationship between paired events survives extinction. (PsycINFO Database Record (c) 2015 APA, all rights reserved).

  4. Attenuating fearful memories: effect of cued extinction on intrusions.

    Science.gov (United States)

    Marks, Elizabeth H; Zoellner, Lori A

    2014-12-01

    Exposure-based therapies for posttraumatic stress disorder are thought to reduce intrusive memories through extinction processes. Methods that enhance extinction may translate to improved treatment. Rat research suggests retrieving a memory via a conditioned stimulus (CS) cue, and then modifying the retrieved memory within a specific reconsolidation window may enhance extinction. In humans, studies (e.g., Kindt & Soeter, 2013; Schiller et al., 2010) using basic learning paradigms show discrepant findings. Using a distressing film paradigm, participants (N = 148) completed fear acquisition and extinction. At extinction, they were randomized to 1 of 3 groups: CS cue within reconsolidation window, CS cue outside window, or non-CS cue within window. Intrusions were assessed 24 hr after extinction. Participants receiving the CS cue and completing extinction within the reconsolidation window had more intrusions (M = 2.40, SD = 2.54) than those cued outside (M = 1.65, SD = 1.70) or those receiving a non-CS cue (M = 1.24, SD = 1.26), F(2, 145) = 4.52, p = .01, d = 0.55. Consistent with the reconsolidation hypothesis, presenting a CS cue does appear to activate a specific period of time during which a memory can be updated. However, the CS cue caused increased, rather than decreased, frequency of intrusions. Understanding parameters of preextinction cueing may help us better understand reconsolidation as a potential memory updating mechanism.

  5. Fear Conditioning and Extinction in Youth with Obsessive Compulsive Disorder

    Science.gov (United States)

    McGuire, Joseph F.; Orr, Scott P.; Wu, Monica S.; Lewin, Adam B.; Small, Brent J.; Phares, Vicky; Murphy, Tanya K.; Wilhelm, Sabine; Pine, Daniel S.; Geller, Daniel; Storch, Eric A.

    2017-01-01

    Background Fear acquisition and extinction are central constructs in the cognitive-behavioral model of obsessive-compulsive disorder (OCD), which underlies exposure-based cognitive-behavioral therapy (CBT). Youth with OCD may have impairments in fear acquisition and extinction that carry treatment implications. We examined these processes using a differential conditioning procedure. Methods Forty-one youth (19 OCD, 22 community comparisons) completed a battery of clinical interviews, rating scales, and a differential conditioning task that included habituation, acquisition, and extinction phases. Skin conductance response (SCR) served as the primary dependent measure. Results During habituation, no difference between groups was observed. During acquisition, differential fear conditioning was observed across participants as evidenced by larger SCRs to the CS+ compared to CS−; there were no between-group differences. Across participants, the number and frequency of OCD symptoms and anxiety severity was associated with greater reactivity to stimuli during acquisition. During extinction, a three-way interaction and follow-up tests revealed that youth with OCD showed a different pattern of SCR extinction compared to the community comparison group. Conclusions Youth with OCD exhibit a different pattern of fear extinction relative to community comparisons. This may be attributed to impaired inhibitory learning and contingency awareness in extinction. Findings suggest the potential benefit of utilizing inhibitory-learning principles in CBT for youth with OCD, and/or augmentative retraining interventions prior to CBT to reduce threat bias and improve contingency detection. PMID:26799264

  6. On Galactic Density Modeling in the Presence of Dust Extinction

    Science.gov (United States)

    Bovy, Jo; Rix, Hans-Walter; Green, Gregory M.; Schlafly, Edward F.; Finkbeiner, Douglas P.

    2016-02-01

    Inferences about the spatial density or phase-space structure of stellar populations in the Milky Way require a precise determination of the effective survey volume. The volume observed by surveys such as Gaia or near-infrared spectroscopic surveys, which have good coverage of the Galactic midplane region, is highly complex because of the abundant small-scale structure in the three-dimensional interstellar dust extinction. We introduce a novel framework for analyzing the importance of small-scale structure in the extinction. This formalism demonstrates that the spatially complex effect of extinction on the selection function of a pencil-beam or contiguous sky survey is equivalent to a low-pass filtering of the extinction-affected selection function with the smooth density field. We find that the angular resolution of current 3D extinction maps is sufficient for analyzing Gaia sub-samples of millions of stars. However, the current distance resolution is inadequate and needs to be improved by an order of magnitude, especially in the inner Galaxy. We also present a practical and efficient method for properly taking the effect of extinction into account in analyses of Galactic structure through an effective selection function. We illustrate its use with the selection function of red-clump stars in APOGEE using and comparing a variety of current 3D extinction maps.

  7. Belief bias and the extinction of induced fear.

    Science.gov (United States)

    Vroling, Maartje S; de Jong, Peter J

    2013-01-01

    Some people show slower extinction of UCS expectancies than other people. Little is known about what predicts such delayed extinction. Extinction requires that people deduce the logical implication of corrective experiences challenging the previously learned CS-UCS contingency. "A strong habitual tendency to confirm beliefs" may therefore be a powerful mechanism immunising against refutation of UCS expectancies. This study investigated whether individual differences in such a belief confirming tendency (a process called "belief bias") may help in explaining individual differences in extinction. We tested whether relatively strong belief bias predicts delayed extinction of experimentally induced UCS expectancies. In a differential aversive conditioning paradigm, we used UCS-irrelevant (Experiment 1) and UCS-relevant (Experiment 2) pictorial stimuli as CS⁺ and CS⁻, and electrical stimulation as UCS. Belief bias indeed predicted delayed extinction of UCS expectancies when the CS⁺ was UCS-relevant (as is typically the case for phobic stimuli, Experiment 2). The study provides preliminary evidence that enhanced belief bias may indeed play a role in the persistence of UCS expectancies, and can thereby contribute to the development and persistence of anxiety disorders. The results also point to the relevance of reasoning tendencies in the search for predictors of delayed extinction of UCS expectancies.

  8. Geography of current and future global mammal extinction risk.

    Science.gov (United States)

    Davidson, Ana D; Shoemaker, Kevin T; Weinstein, Ben; Costa, Gabriel C; Brooks, Thomas M; Ceballos, Gerardo; Radeloff, Volker C; Rondinini, Carlo; Graham, Catherine H

    2017-01-01

    Identifying which species are at greatest risk, what makes them vulnerable, and where they are distributed are central goals for conservation science. While knowledge of which factors influence extinction risk is increasingly available for some taxonomic groups, a deeper understanding of extinction correlates and the geography of risk remains lacking. Here, we develop a predictive random forest model using both geospatial and mammalian species' trait data to uncover the statistical and geographic distributions of extinction correlates. We also explore how this geography of risk may change under a rapidly warming climate. We found distinctive macroecological relationships between species-level risk and extinction correlates, including the intrinsic biological traits of geographic range size, body size and taxonomy, and extrinsic geographic settings such as seasonality, habitat type, land use and human population density. Each extinction correlate exhibited ranges of values that were especially associated with risk, and the importance of different risk factors was not geographically uniform across the globe. We also found that about 10% of mammals not currently recognized as at-risk have biological traits and occur in environments that predispose them towards extinction. Southeast Asia had the most actually and potentially threatened species, underscoring the urgent need for conservation in this region. Additionally, nearly 40% of currently threatened species were predicted to experience rapid climate change at 0.5 km/year or more. Biological and environmental correlates of mammalian extinction risk exhibit distinct statistical and geographic distributions. These results provide insight into species-level patterns and processes underlying geographic variation in extinction risk. They also offer guidance for future conservation research focused on specific geographic regions, or evaluating the degree to which species-level patterns mirror spatial variation in the

  9. Geography of current and future global mammal extinction risk.

    Directory of Open Access Journals (Sweden)

    Ana D Davidson

    Full Text Available Identifying which species are at greatest risk, what makes them vulnerable, and where they are distributed are central goals for conservation science. While knowledge of which factors influence extinction risk is increasingly available for some taxonomic groups, a deeper understanding of extinction correlates and the geography of risk remains lacking. Here, we develop a predictive random forest model using both geospatial and mammalian species' trait data to uncover the statistical and geographic distributions of extinction correlates. We also explore how this geography of risk may change under a rapidly warming climate. We found distinctive macroecological relationships between species-level risk and extinction correlates, including the intrinsic biological traits of geographic range size, body size and taxonomy, and extrinsic geographic settings such as seasonality, habitat type, land use and human population density. Each extinction correlate exhibited ranges of values that were especially associated with risk, and the importance of different risk factors was not geographically uniform across the globe. We also found that about 10% of mammals not currently recognized as at-risk have biological traits and occur in environments that predispose them towards extinction. Southeast Asia had the most actually and potentially threatened species, underscoring the urgent need for conservation in this region. Additionally, nearly 40% of currently threatened species were predicted to experience rapid climate change at 0.5 km/year or more. Biological and environmental correlates of mammalian extinction risk exhibit distinct statistical and geographic distributions. These results provide insight into species-level patterns and processes underlying geographic variation in extinction risk. They also offer guidance for future conservation research focused on specific geographic regions, or evaluating the degree to which species-level patterns mirror spatial

  10. Ketamine accelerates fear extinction via mTORC1 signaling.

    Science.gov (United States)

    Girgenti, Matthew J; Ghosal, Sriparna; LoPresto, Dora; Taylor, Jane R; Duman, Ronald S

    2017-04-01

    Impaired fear extinction contributes to the persistence of post-traumatic stress disorder (PTSD), and can be utilized for the study of novel therapeutic agents. Glutamate plays an important role in the formation of traumatic memories, and in the pathophysiology and treatment of PTSD, highlighting several possible drug targets. Recent clinical studies demonstrate that infusion of ketamine, a glutamate NMDA receptor antagonist, rapidly and significantly reduces symptom severity in PTSD patients. In the present study, we examine the mechanisms underlying the actions of ketamine in a rodent model of fear conditioning, extinction, and renewal. Rats received ketamine or saline 24h after fear conditioning and were then subjected to extinction-training on each of the following three days. Ketamine administration enhanced extinction on the second day of training (i.e., reduced freezing behavior to cue) and produced a long-lasting reduction in freezing on exposure to cue plus context 8days later. Additionally, ketamine and extinction exposure increased levels of mTORC1 in the medial prefrontal cortex (mPFC), a region involved in the acquisition and retrieval of extinction, and infusion of the selective mTORC1 inhibitor rapamycin into the mPFC blocked the effects of ketamine on extinction. Ketamine plus extinction also increased cFos in the mPFC and administration of a glutamate-AMPA receptor antagonist blocked the effects of ketamine. These results support the hypothesis that ketamine produces long-lasting mTORC1/protein synthesis and activity dependent effects on neuronal circuits that enhance the expression of extinction and could represent a novel approach for the treatment of PTSD. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Replacement treatment during extinction training with the atypical dopamine uptake inhibitor, JHW-007, reduces relapse to methamphetamine seeking.

    Science.gov (United States)

    Dassanayake, Ashlea F; Canales, Juan J

    2018-04-03

    There are currently no approved medications to effectively counteract the effects of methamphetamine (METH), reduce its abuse and prolong abstinence from it. Data accumulated in recent years have shown that a range of N-substituted benztropine (BZT) analogues possesses psychopharmacological features consistent with those of a potential replacement or "substitute" treatment for stimulant addiction. On the other hand, the evidence that antidepressant therapy may effectively prevent relapse to stimulant seeking is controversial. Here, we compared in rats the ability of the BZT analogue and high affinity dopamine (DA) reuptake inhibitor, JHW-007, and the antidepressant, trazodone, administered during extinction sessions after chronic METH self-administration, to alter METH-primed reinstatement of drug seeking. The data showed that trazodone produced paradoxical effects on lever pressing during extinction of METH self-administration, decreasing active, but increasing inactive, lever pressing. JHW-007 did not have any observable effects on extinction training. Importantly, JHW-007 significantly attenuated METH-primed reinstatement, whereas trazodone enhanced it. These findings lend support to the candidacy of selective DA uptake blockers, such as JHW-007, as potential treatments for METH addiction, but not to the use of antidepressant medication as a single therapeutic approach for relapse prevention. Copyright © 2018 Elsevier B.V. All rights reserved.

  12. The effects of a session of resistance training on sleep patterns in the elderly.

    Science.gov (United States)

    Viana, Valter A Rocha; Esteves, Andrea Maculano; Boscolo, Rita Aurélia; Grassmann, Viviane; Santana, Marcos Gonçalves; Tufik, Sergio; de Mello, Marco Túlio

    2012-07-01

    The purpose of this study was to evaluate the influence of a session of resistance training on the sleep patterns of elderly people. Forty men aged 65-80 years who were sedentary and clinically healthy were divided into two groups: the control group (n = 18) and the resistance group (n = 22). Both groups underwent two polysomnography tests, one at baseline and another after either a resistance training session (the resistance group) or no physical exercise (the control group). The resistance training session was based on 60% of one repetition maximum (a test that assesses the maximum force). We observed that the frequency with which the control group awoke (arousal index) increased from 16.29 ± 6.06 events/h to 20.09 ± 6.9 events/h, and in the resistance group, it decreased from 22.27 ± 11 events/h to 20.41 ± 8.57 events/h (t = 2.10 and p = 0.04). For stage-1 sleep, there was an increase from 4.96% at baseline to 5.40% in the control group, and there was a decrease in the resistance group from 8.32 to 6.21% after the exercise session (t = 2.12 and p = 0.04). A session of resistance training at 60% of one repetition maximum was able to modify the sleep pattern in men aged 65-80 years, suggesting that physical exercise has a modest influence on sleep consolidation.

  13. Oxygen saturation and heart rate monitoring during a single session of early rehabilitation after cardiac surgery.

    Science.gov (United States)

    Sala, Vittorio; Petrucci, Lucia; Monteleone, Serena; Dall'Angelo, Anna; Miracca, Stefania; Conte, Teresa; Carlisi, Ettore; Ricotti, Susanna; D'Armini, Andrea M; Dalla Toffola, Elena

    2016-02-01

    Early rehabilitation after cardiac surgery aims to prevent immobilization, to reduce the effects of surgery on the respiratory function and to facilitate the recovery of autonomy in the activities of daily living (ADL), after discharge. Nevertheless the optimal perioperative physical therapy care for patients undergoing cardiac surgery is not well established. Moreover, most of the studies monitored peripheral oxygen saturation (SpO2) and heart rate (HR) during surgery or focused only on their recovery after rehabilitation and not on their pathways during a session of exercises. To monitor peripheral oxygen saturation and HR before, during and at the end of a single session of early rehabilitation after cardiac surgery, so testing our protocol's safety. A case series. Department of Cardiothoracic Surgery, inpatients. Forty-eight consecutive inpatients (35 M), mean age 61 years, with cardiovascular disease (CVD), who underwent cardiac surgery. We monitored SpO2%, HR, systemic blood pressure (BP), pain in the thoracic wound (VAS) and rate of perceived exertion (RPE) during the rehabilitation session after weaning from oxygen therapy. During all phases mean SpO2 was 94% (±1.8) and mean HR was 85 bpm (±13.3). Number of desaturation events were 14 in total and mean of % of time with SpO2<90% was 3 (±6.5) during all the rehabilitative session. Moreover, mean BP after reaching the sitting position was 124.7 (±11.9)/78.6 (±8.4) and after ambulation was 131.5 (±11.5)/82.9 (±7.3). The monitoring peripheral oxygen saturation and HR during and not only before and at the end of a standardized early rehabilitation session helped us to ensure the safety of our protocol. Because of its feasibility, safety and reproducibility our rehabilitation treatment has been applied to different types of surgical inpatients in order to limit the negative consequences of immobilization.

  14. Extinction in finite perfect crystals: Case of a sphere

    International Nuclear Information System (INIS)

    Al Haddad, M.; Becker, P.

    1990-01-01

    The extinction factor in finite perfect crystals is calculated from pure dynamical theory. In particular, a detailed solution is proposed for a sphere, in which case the extinction factor depends on the Bragg angle θ and the parameter (R/Λ), where R is the radius of the crystal and Λ the extinction length. An approximate solution based on the Laue geometry is proposed and corrections to take care of the complex boundary conditions are presented. An expression easily usable in refinement programs is proposed that fits the exact value to better than 1%. (orig.)

  15. Extinction partially reverts structural changes associated with remote fear memory

    DEFF Research Database (Denmark)

    Vetere, Gisella; Restivo, Leonardo; Novembre, Giovanni

    2011-01-01

    Structural synaptic changes occur in medial prefrontal cortex circuits during remote memory formation. Whether extinction reverts or further reshapes these circuits is, however, unknown. Here we show that the number and the size of spines were enhanced in anterior cingulate (aCC) and infralimbic...... (ILC) cortices 36 d following contextual fear conditioning. Upon extinction, aCC spine density returned to baseline, but the enhanced proportion of large spines did not. Differently, ILC spine density remained elevated, but the size of spines decreased dramatically. Thus, extinction partially erases...

  16. Variations in ultraviolet extinction: effect of polarization revisited

    International Nuclear Information System (INIS)

    Greenberg, J.M.; Chlewicki, G.; Rijksuniversiteit Groningen

    1987-01-01

    The alignment of the particles responsible for the polarization and visual extinction is shown to provide a basis for changing the saturation level of the ultraviolet extinction without changing the particle sizes. If the particles are well aligned, it is predicted that there should be significantly lower extinction in the ultraviolet relative to the visible for stars viewed perpendicular to magnetic-field lines (maximum polarization) as compared with those viewed across the field lines. Preliminary evidence for such an effect is noted in Carina. (author)

  17. High extinction ratio integrated optical modulator for quantum telecommunication systems

    Science.gov (United States)

    Tronev, A.; Parfenov, M.; Agruzov, P.; Ilichev, I.; Shamray, A.

    2018-01-01

    A method for increasing the extinction ratio of integrated optical Mach-Zehnder modulators based on LiNbO3 via the photorefractive effect is proposed. The influence of the photorefractive effect on the X- and Y-splitters of intensity modulators is experimentally studied. An increase in the modulator extinction ratio by 17 dB (from 30 to 47 dB) is obtained. It is shown that fabricated modulators with a high extinction ratio are important for quantum key distribution systems.

  18. The use of extinction corrections in neutron diffraction experiments

    International Nuclear Information System (INIS)

    Delapalme, A.

    1987-08-01

    Extinction can be treated through various models originating in either kinematical (intensity coupling) or dynamical (wave coupling) theories. For most crystals the situation is intermediate between these two extreme cases and extinction models are necessary to obtain precise Fourier components (structure factors) and the electronic and magnetic distribution in molecules and crystals. New models reveal new parameters and new effects of their role in the Extinction phenomena, but the phenomenological aspect of the solutions shows the difficulty to describe adequately what happens in real crystals

  19. Rarity in mass extinctions and the future of ecosystems

    Science.gov (United States)

    Hull, Pincelli M.; Darroch, Simon A. F.; Erwin, Douglas H.

    2015-12-01

    The fossil record provides striking case studies of biodiversity loss and global ecosystem upheaval. Because of this, many studies have sought to assess the magnitude of the current biodiversity crisis relative to past crises—a task greatly complicated by the need to extrapolate extinction rates. Here we challenge this approach by showing that the rarity of previously abundant taxa may be more important than extinction in the cascade of events leading to global changes in the biosphere. Mass rarity may provide the most robust measure of our current biodiversity crisis relative to those past, and new insights into the dynamics of mass extinction.

  20. Estimating times of extinction in the fossil record.

    Science.gov (United States)

    Wang, Steve C; Marshall, Charles R

    2016-04-01

    Because the fossil record is incomplete, the last fossil of a taxon is a biased estimate of its true time of extinction. Numerous methods have been developed in the palaeontology literature for estimating the true time of extinction using ages of fossil specimens. These methods, which typically give a confidence interval for estimating the true time of extinction, differ in the assumptions they make and the nature and amount of data they require. We review the literature on such methods and make some recommendations for future directions. © 2016 The Author(s).