WorldWideScience

Sample records for extinct animal programs

  1. The extinct animal show: the paleoimagery tradition and computer generated imagery in factual television programs.

    Science.gov (United States)

    Campbell, Vincent

    2009-03-01

    Extinct animals have always been popular subjects for the media, in both fiction, and factual output. In recent years, a distinctive new type of factual television program has emerged in which computer generated imagery is used extensively to bring extinct animals back to life. Such has been the commercial audience success of these programs that they have generated some public and academic debates about their relative status as science, documentary, and entertainment, as well as about their reflection of trends in factual television production, and the aesthetic tensions in the application of new media technologies. Such discussions ignore a crucial contextual feature of computer generated extinct animal programs, namely the established tradition of paleoimagery. This paper examines a selection of extinct animal shows in terms of the dominant frames of the paleoimagery genre. The paper suggests that such an examination has two consequences. First, it allows for a more context-sensitive evaluation of extinct animal programs, acknowledging rather than ignoring relevant representational traditions. Second, it allows for an appraisal and evaluation of public and critical reception of extinct animal programs above and beyond the traditional debates about tensions between science, documentary, entertainment, and public understanding.

  2. All about Endangered and Extinct Animals. Animal Life for Children. [Videotape].

    Science.gov (United States)

    2000

    While there are thousands of different animals in the world, some have been extinct for many years and others are on the verge of extinction. In this videotape, students learn about the natural and man-made factors that lead to the endangerment and extinction of animals. Children find out why it is essential for people to help all forms of…

  3. Resurrecting ancient animal genomes: the extinct moa and more.

    Science.gov (United States)

    Huynen, Leon; Millar, Craig D; Lambert, David M

    2012-08-01

    Recently two developments have had a major impact on the field of ancient DNA (aDNA). First, new advances in DNA sequencing, in combination with improved capture/enrichment methods, have resulted in the recovery of orders of magnitude more DNA sequence data from ancient animals. Second, there has been an increase in the range of tissue types employed in aDNA. Hair in particular has proven to be very successful as a source of DNA because of its low levels of contamination and high level of ancient endogenous DNA. These developments have resulted in significant advances in our understanding of recently extinct animals: namely their evolutionary relationships, physiology, and even behaviour. Hair has been used to recover the first complete ancient nuclear genome, that of the extinct woolly mammoth, which then facilitated the expression and functional analysis of haemoglobins. Finally, we speculate on the consequences of these developments for the possibility of recreating extinct animals. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Endangered & Extinct Animals. Animal Life in Action[TM]. Schlessinger Science Library. [Videotape].

    Science.gov (United States)

    2000

    This 23-minute videotape for grades 5-8, presents the myriad of animal life that exists on the planet. Students can view and perform experiments and investigations that help explain animal traits and habits. Due to environmental factors and human interference, many of Earth's creatures have ceased to exist or are on the verge of extinction. In…

  5. Endangered & Extinct Animals. Animal Life in Action[TM]. Schlessinger Science Library. [Videotape].

    Science.gov (United States)

    2000

    This 23-minute videotape for grades 5-8, presents the myriad of animal life that exists on the planet. Students can view and perform experiments and investigations that help explain animal traits and habits. Due to environmental factors and human interference, many of Earth's creatures have ceased to exist or are on the verge of extinction. In…

  6. Laboratory Animal Sciences Program (LASP)

    Data.gov (United States)

    Federal Laboratory Consortium — The Laboratory Animal Sciences Program (LASP) is a comprehensive resource for scientists performing animal-based research to gain a better understanding of cancer,...

  7. Progress to extinction: increased specialisation causes the demise of animal clades

    Science.gov (United States)

    Raia, P.; Carotenuto, F.; Mondanaro, A.; Castiglione, S.; Passaro, F.; Saggese, F.; Melchionna, M.; Serio, C.; Alessio, L.; Silvestro, D.; Fortelius, M.

    2016-08-01

    Animal clades tend to follow a predictable path of waxing and waning during their existence, regardless of their total species richness or geographic coverage. Clades begin small and undifferentiated, then expand to a peak in diversity and range, only to shift into a rarely broken decline towards extinction. While this trajectory is now well documented and broadly recognised, the reasons underlying it remain obscure. In particular, it is unknown why clade extinction is universal and occurs with such surprising regularity. Current explanations for paleontological extinctions call on the growing costs of biological interactions, geological accidents, evolutionary traps, and mass extinctions. While these are effective causes of extinction, they mainly apply to species, not clades. Although mass extinctions is the undeniable cause for the demise of a sizeable number of major taxa, we show here that clades escaping them go extinct because of the widespread tendency of evolution to produce increasingly specialised, sympatric, and geographically restricted species over time.

  8. Permo-Triassic vertebrate extinctions: A program

    Science.gov (United States)

    Olson, E. C.

    1988-01-01

    Since the time of the Authors' study on this subject, a great deal of new information has become available. Concepts of the nature of extinctions have changed materially. The Authors' conclusion that a catastrophic event was not responsible for the extinction of vertebrates has modified to the extent that hypotheses involving either the impact of a massive extra-terrestrial body or volcanism provide plausible but not currently fully testable hypotheses. Stated changes resulted in a rapid decrease in organic diversity, as the ratio of origins of taxa to extinctions shifted from strongly positive to negative, with momentary equilibrium being reached at about the Permo-Triassic boundary. The proximate causes of the changes in the terrestrial biota appear to lie in two primary factors: (1) strong climatic changes (global mean temperatures, temperature ranges, humidity) and (2) susceptibility of the dominant vertebrates (large dicynodonts) and the glossopteris flora to disruption of the equlibrium of the world ecosystem. The following proximate causes have been proposed: (1) rhythmic fluctuations in solar radiation, (2) tectonic events as Pangea assembled, altering land-ocean relationships, patterns of wind and water circulation and continental physiography, (3) volcanism, and (4) changes subsequent to impacts of one or more massive extra terrestrial objects, bodies or comets. These hypotheses are discussed.

  9. Body Size Preference of Marine Animals in Relation to Extinction Selectivity

    Science.gov (United States)

    Sriram, A.; Idgunji, S.; Heim, N. A.; Payne, J.

    2014-12-01

    Our project encompasses an extremely specific aspect in relation to the five mass extinctions in geologic history. We asked ourselves whether larger or smaller body sizes would be better suited for surviving a mass extinction. To conduct research for our project, we used the body sizes of 17,172 marine animal genera as our primary data. These animals include echinoderms, arthropods, chordates, mollusks, and brachiopods. These creatures are perfect model organisms in terms of finding data on them because they have an excellent fossil record, and are well documented. We focused on the mean body size of these animals before and after each of the five mass extinctions (end-Ordovician, Late Devonian, end-Permian, end-Triassic, and end-Cretaceous). Our hypothesis was that the average biovolume of animals increased after each of the extinctions, with the mean size being greater after than it was before. Our size data is from the Ellis & Messina Catalogue of Ostracoda and the Treatise on Invertebrate Paleontology. We obtained stratigraphic range data The Treatise and Sepkoski (2002). In our analyses, we compared the mean size of the different animal genera before and after each extinction event. We further partitioned size change across mass extinction boundaries into three categories: the surviving genera, the extinct genera, and the newly originating genera that came about after the extinction. According to our analyses, the mean sizes did not change significantly from the genera living during the stages before the extinctions and after the extinctions. From our results, we can assume that there were not enough major increases in the overall volume of the organisms to warrant a definite conclusion that extinctions lead to larger body sizes. Further support for our findings came from the T-tests in our R code. Only the Cretaceous period showed true evidence for size changing because of the extinction; in this case, the mean size decreased. T-tests for the Cretaceous

  10. Animal models of extinction-induced depression: loss of reward and its consequences.

    Science.gov (United States)

    Huston, Joseph P; Silva, Maria A de Souza; Komorowski, Mara; Schulz, Daniela; Topic, Bianca

    2013-11-01

    The absence or loss of rewards or reinforcers holds a major role in the development of depression in humans. In spite of the prevalence of extinction-induced depression (EID) in humans, few attempts have been made to establish animal models thereof. Here we present the concept of extinction-related depression and summarize the results of two sets of studies in our attempt to create animal models of EID, one set based on extinction after positive reinforcement in the Skinner-box, the other on extinction after negative reinforcement - escape from water. We found various behaviors emitted during the extinction trials that responded to treatment with antidepressant drugs: Accordingly, the important behavioral marker for EID during extinction of escape from the water was immobility. During extinction after positive reinforcement the important indices for extinction-induced depression are the withdrawal from the former site of reward, biting behavior and rearing up on the hind legs. Avoidance behavior and biting may model aspects of human depressive behavior, which may include withdrawal or avoidance as well as aggressive-like behaviors.

  11. Fear conditioning and extinction across development: evidence from human studies and animal models.

    Science.gov (United States)

    Shechner, Tomer; Hong, Melanie; Britton, Jennifer C; Pine, Daniel S; Fox, Nathan A

    2014-07-01

    The ability to differentiate danger and safety through associative processes emerges early in life. Understanding the mechanisms underlying associative learning of threat and safety can clarify the processes that shape development of normative fears and pathological anxiety. Considerable research has used fear conditioning and extinction paradigms to delineate underlying mechanisms in animals and human adults; however, little is known about these mechanisms in children and adolescents. The current paper summarizes the empirical data on the development of fear conditioning and extinction. It reviews methodological considerations and future directions for research on fear conditioning and extinction in pediatric populations.

  12. Fear conditioning and extinction across development: Evidence from human studies and animal models☆

    Science.gov (United States)

    Shechner, Tomer; Hong, Melanie; Britton, Jennifer C.; Pine, Daniel S.; Fox, Nathan A.

    2015-01-01

    The ability to differentiate danger and safety through associative processes emerges early in life. Understanding the mechanisms underlying associative learning of threat and safety can clarify the processes that shape development of normative fears and pathological anxiety. Considerable research has used fear conditioning and extinction paradigms to delineate underlying mechanisms in animals and human adults; however, little is known about these mechanisms in children and adolescents. The current paper summarizes the empirical data on the development of fear conditioning and extinction. It reviews methodological considerations and future directions for research on fear conditioning and extinction in pediatric populations. PMID:24746848

  13. The use of cognitive enhancers in animal models of fear extinction.

    Science.gov (United States)

    Kaplan, Gary B; Moore, Katherine A

    2011-08-01

    In anxiety disorders, such as posttraumatic stress disorders and phobias, classical conditioning pairs natural (unconditioned) fear-eliciting stimuli with contextual or discrete cues resulting in enduring fear responses to multiple stimuli. Extinction is an active learning process that results in a reduction of conditioned fear responses after conditioned stimuli are no longer paired with unconditioned stimuli. Fear extinction often produces incomplete effects and this highlights the relative permanence of bonds between conditioned stimuli and conditioned fear responses. The animal research literature is rich in its demonstration of cognitive enhancing agents that alter fear extinction. This review specifically examines the fear extinguishing effects of cognitive enhancers that act on gamma-aminobutyric acid (GABA), glutamatergic, cholinergic, adrenergic, dopaminergic, and cannabinoid signaling pathways. It also examines the effects of compounds that alter epigenetic and neurotrophic mechanisms in fear extinction. Of these cognitive enhancers, glutamatergic N-methyl d-aspartate (NMDA) receptor agonists, such as D-cycloserine, have enhanced fear extinction in a context-, dose- and time-dependent manner. Agents that function as glutamatergic α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor agonists, alpha2-adrenergic receptor antagonists (such as yohimbine), neurotrophic factors (brain derived neurotrophic factor or BDNF) and histone deacetylase inhibitors (valproate and sodium butyrate) also improve fear extinction in animals. However, some have anxiogenic effects and their contextual and temporal effects need to be more reliably demonstrated. Various cognitive enhancers produce changes in cortico-amygdala synaptic plasticity through multiple mechanisms and these neural changes enhance fear extinction. We need to better define the changes in neural plasticity produced by these agents in order to develop more effective compounds. In the clinical

  14. Estimating rates of local species extinction, colonization and turnover in animal communities

    Science.gov (United States)

    Nichols, James D.; Boulinier, T.; Hines, J.E.; Pollock, K.H.; Sauer, J.R.

    1998-01-01

    Species richness has been identified as a useful state variable for conservation and management purposes. Changes in richness over time provide a basis for predicting and evaluating community responses to management, to natural disturbance, and to changes in factors such as community composition (e.g., the removal of a keystone species). Probabilistic capture-recapture models have been used recently to estimate species richness from species count and presence-absence data. These models do not require the common assumption that all species are detected in sampling efforts. We extend this approach to the development of estimators useful for studying the vital rates responsible for changes in animal communities over time; rates of local species extinction, turnover, and colonization. Our approach to estimation is based on capture-recapture models for closed animal populations that permit heterogeneity in detection probabilities among the different species in the sampled community. We have developed a computer program, COMDYN, to compute many of these estimators and associated bootstrap variances. Analyses using data from the North American Breeding Bird Survey (BBS) suggested that the estimators performed reasonably well. We recommend estimators based on probabilistic modeling for future work on community responses to management efforts as well as on basic questions about community dynamics.

  15. Ecological networks are more sensitive to plant than to animal extinction under climate change

    Science.gov (United States)

    Schleuning, Matthias; Fründ, Jochen; Schweiger, Oliver; Welk, Erik; Albrecht, Jörg; Albrecht, Matthias; Beil, Marion; Benadi, Gita; Blüthgen, Nico; Bruelheide, Helge; Böhning-Gaese, Katrin; Dehling, D. Matthias; Dormann, Carsten F.; Exeler, Nina; Farwig, Nina; Harpke, Alexander; Hickler, Thomas; Kratochwil, Anselm; Kuhlmann, Michael; Kühn, Ingolf; Michez, Denis; Mudri-Stojnić, Sonja; Plein, Michaela; Rasmont, Pierre; Schwabe, Angelika; Settele, Josef; Vujić, Ante; Weiner, Christiane N.; Wiemers, Martin; Hof, Christian

    2016-01-01

    Impacts of climate change on individual species are increasingly well documented, but we lack understanding of how these effects propagate through ecological communities. Here we combine species distribution models with ecological network analyses to test potential impacts of climate change on >700 plant and animal species in pollination and seed-dispersal networks from central Europe. We discover that animal species that interact with a low diversity of plant species have narrow climatic niches and are most vulnerable to climate change. In contrast, biotic specialization of plants is not related to climatic niche breadth and vulnerability. A simulation model incorporating different scenarios of species coextinction and capacities for partner switches shows that projected plant extinctions under climate change are more likely to trigger animal coextinctions than vice versa. This result demonstrates that impacts of climate change on biodiversity can be amplified via extinction cascades from plants to animals in ecological networks. PMID:28008919

  16. On the choice of statistical models for estimating occurrence and extinction from animal surveys

    Science.gov (United States)

    Dorazio, R.M.

    2007-01-01

    In surveys of natural animal populations the number of animals that are present and available to be detected at a sample location is often low, resulting in few or no detections. Low detection frequencies are especially common in surveys of imperiled species; however, the choice of sampling method and protocol also may influence the size of the population that is vulnerable to detection. In these circumstances, probabilities of animal occurrence and extinction will generally be estimated more accurately if the models used in data analysis account for differences in abundance among sample locations and for the dependence between site-specific abundance and detection. Simulation experiments are used to illustrate conditions wherein these types of models can be expected to outperform alternative estimators of population site occupancy and extinction. ?? 2007 by the Ecological Society of America.

  17. Fear extinction and BDNF: translating animal models of PTSD to the clinic.

    Science.gov (United States)

    Andero, R; Ressler, K J

    2012-07-01

    Brain-derived neurotrophic factor (BDNF) is the most studied neurotrophin involved in synaptic plasticity processes that are required for long-term learning and memory. Specifically, BDNF gene expression and activation of its high-affinity tropomyosin-related kinase B (TrkB) receptor are necessary in the amygdala, hippocampus and prefrontal cortex for the formation of emotional memories, including fear memories. Among the psychiatric disorders with altered fear processing, there is post-traumatic stress disorder (PTSD) which is characterized by an inability to extinguish fear memories. Since BDNF appears to enhance extinction of fear, targeting impaired extinction in anxiety disorders such as PTSD via BDNF signalling may be an important and novel way to enhance treatment efficacy. The aim of this review is to provide a translational point of view that stems from findings in the BDNF regulation of synaptic plasticity and fear extinction. In addition, there are different systems that seem to alter fear extinction through BDNF modulation like the endocannabinoid system and the hypothalamic-pituitary adrenal axis. Recent work also finds that the pituitary adenylate cyclase-activating polypeptide and PAC1 receptor, which are upstream of BDNF activation, may be implicated in PTSD. Especially interesting are data that exogenous fear extinction enhancers such as antidepressants, histone deacetylases inhibitors and D-cycloserine, a partial N-methyl d-aspartate agonist, may act through or in concert with the BDNF-TrkB system. Finally, we review studies where recombinant BDNF and a putative TrkB agonist, 7,8-dihydroxyflavone, may enhance extinction of fear. These approaches may lead to novel agents that improve extinction in animal models and eventually humans.

  18. Preventing return of fear in an animal model of anxiety: additive effects of massive extinction and extinction in multiple contexts.

    Science.gov (United States)

    Laborda, Mario A; Miller, Ralph R

    2013-06-01

    Fear conditioning and experimental extinction have been presented as models of anxiety disorders and exposure therapy, respectively. Moreover, the return of fear serves as a model of relapse after exposure therapy. Here we present two experiments, with rats as subjects in a lick suppression preparation, in which we assessed the additive effects of two different treatments to attenuate the return of fear. First, we evaluated whether two phenomena known to generate return of fear (i.e., spontaneous recovery and renewal) summate to produce a stronger reappearance of extinguished fear. At test, rats evaluated outside the extinction context following a long delay after extinction (i.e., a delayed context shift) exhibited greater return of extinguished fear than rats evaluated outside the extinction context alone, but return of extinguished fear following a delayed context shift did not significantly differ from the return of fear elicited in rats tested following a long delay after extinction alone. Additionally, extinction in multiple contexts and a massive extinction treatment each attenuated the strong return of fear produced by a delayed context shift. Moreover, the conjoint action of these treatments was significantly more successful in preventing the reappearance of extinguished fear, suggesting that extensive cue exposure administered in several different therapeutic settings has the potential to reduce relapse after therapy for anxiety disorders, more than either manipulation alone.

  19. Animal Resource Program | Center for Cancer Research

    Science.gov (United States)

    CCR Animal Resource Program The CCR Animal Resource Program plans, develops, and coordinates laboratory animal resources for CCR’s research programs. We also provide training, imaging, and technology development in support of moving basic discoveries to the clinic. The ARP Manager:

  20. 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.

  1. Using physical models to study the gliding performance of extinct animals.

    Science.gov (United States)

    Koehl, M A R; Evangelista, Dennis; Yang, Karen

    2011-12-01

    Aerodynamic studies using physical models of fossil organisms can provide quantitative information about how performance of defined activities, such as gliding, depends on specific morphological features. Such analyses allow us to rule out hypotheses about the function of extinct organisms that are not physically plausible and to determine if and how specific morphological features and postures affect performance. The purpose of this article is to provide a practical guide for the design of dynamically scaled physical models to study the gliding of extinct animals using examples from our research on the theropod dinosaur, †Microraptor gui, which had flight feathers on its hind limbs as well as on its forelimbs. Analysis of the aerodynamics of †M. gui can shed light on the design of gliders with large surfaces posterior to the center of mass and provide functional information to evolutionary biologists trying to unravel the origins of flight in the dinosaurian ancestors and sister groups to birds. Measurements of lift, drag, side force, and moments in pitch, roll, and yaw on models in a wind tunnel can be used to calculate indices of gliding and parachuting performance, aerodynamic static stability, and control effectiveness in maneuvering. These indices permit the aerodynamic performance of bodies of different shape, size, stiffness, texture, and posture to be compared and thus can provide insights about the design of gliders, both biological and man-made. Our measurements of maximum lift-to-drag ratios of 2.5-3.1 for physical models of †M. gui suggest that its gliding performance was similar to that of flying squirrels and that the various leg postures that might have been used by †M. gui make little difference to that aspect of aerodynamic performance. We found that body orientation relative to the movement of air past the animal determines whether it is difficult or easy to maneuver.

  2. 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...

  3. Effects of the protein synthesis inhibitor cycloheximide on anxiety-like extinction behavior in an animal model of post-traumatic stress.

    Science.gov (United States)

    Sandusky, Leslie A; Flint, Robert W; McNay, Ewan C

    2012-05-16

    The effect of cycloheximide (CXM), a protein synthesis inhibitor, on memory reconsolidation and extinction was explored in rats using a model of post-traumatic stress. Forty-two animals were exposed to predator stress followed by 1, 2, or 4 extinction trials. Saline or CXM (1 mg/kg) was administered following the last extinction trial and anxiety was measured in the elevated-plus maze (EPM) seventy-two hours later. Saline control animals exhibited elevated anxiety levels in comparison to a no stress control group. Cycloheximide appeared to maintain stress-induced anxiety responses, which otherwise declined with repeated extinction trials in the saline control groups. These findings suggest that cycloheximide may have induced amnesia for extinction, leaving the target memory of the predatory stress intact resulting in elevated levels of anxiety. The relationships between de novo protein synthesis and reconsolidation of anxiety-related memories following extinction trials may be more complex than originally thought.

  4. 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.

  5. Occupational medicine programs for animal research facilities.

    Science.gov (United States)

    Wald, Peter H; Stave, Gregg M

    2003-01-01

    Occupational medicine is a key component of a comprehensive occupational health and safety program in support of laboratory animal research and production facilities. The mission of the department is to maximize employee health and productivity utilizing a population health management approach, which includes measurement and analysis of health benefits utilization. The department works in close cooperation with other institutional health and safety professionals to identify potential risks from exposure to physical, chemical, and biological hazards in the workplace. As soon as exposures are identified, the department is responsible for formulating and providing appropriate medical surveillance programs. Occupational medicine is also responsible for targeted delivery of preventive and wellness services; management of injury, disease, and disability; maintenance of medical information; and other clinic services required by the institution. Recommendations are provided for the organization and content of occupational medicine programs for animal research facilities.

  6. Rarity, species richness, and the threat of extinction--are plants the same as animals?

    Directory of Open Access Journals (Sweden)

    Sandra Knapp

    2011-05-01

    Full Text Available Assessment of conservation status is done both for areas or habitats and for species (or taxa. IUCN Red List categories have been the principal method of categorising species in terms of extinction risk, and have been shown to be robust and helpful in the groups for which they have been developed. A recent study highlights properties associated with extinction risk in flowering plants, focusing on the species-rich hot spot of the Cape region of South Africa, and concludes that merely following methods derived from studies of vertebrates may not provide the best estimates of extinction risk for plants. Biology, geography, and history all are important factors in risk, and the study poses many questions about how we categorise and assess species for conservation priorities.

  7. A Reminder of Extinction Reduces Relapse in an Animal Model of Voluntary Behavior

    Science.gov (United States)

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

    2017-01-01

    One experiment with rats explored whether an extinction-cue prevents the recovery of extinguished lever-pressing responses. Initially, rats were trained to perform one instrumental response (R1) for food in Context A, and a different instrumental response (R2) in Context B. Then, responses were extinguished each in the alternate context (R1 in…

  8. A Reminder of Extinction Reduces Relapse in an Animal Model of Voluntary Behavior

    Science.gov (United States)

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

    2017-01-01

    One experiment with rats explored whether an extinction-cue prevents the recovery of extinguished lever-pressing responses. Initially, rats were trained to perform one instrumental response (R1) for food in Context A, and a different instrumental response (R2) in Context B. Then, responses were extinguished each in the alternate context (R1 in…

  9. Relationships between ocean anoxia, the biological pump, and marine animal life during the Permian-Triassic mass extinction (Invited)

    Science.gov (United States)

    Meyer, K. M.; Schaal, E. K.; Payne, J.

    2013-12-01

    Ocean anoxia/euxinia and carbon cycle instability have long been linked to the end-Permian mass extinction and the Early Triassic interval of delayed or interrupted biotic recovery. Many hypotheses to explain this extinction event invoke the release of greenhouse gases during the emplacement of the Siberian Traps, which likely triggered abrupt changes in marine biogeochemical cycling, atmospheric chemistry, and biodiversity. However, the precise ways in which volcanism and these perturbations are linked and how they governed the tempo and mode of biotic recovery remain poorly understood. Here we highlight new C, Ca, and Sr isotopic data that serve to link volcanic CO2 inputs to changes in marine biogeochemistry and environmental change. We then examine the relationship between ocean biogeochemistry, the biological pump, and marine animal ecosystems during the end-Permian mass extinction and Early Triassic recovery. Finally, we use numerical simulations to probe whether these relationships also explain broad Phanerozoic trends in ocean nutrient status, anoxia, and productivity of marine ecosystems.

  10. Roles of Animation Tools in Understanding Programming Concepts

    Science.gov (United States)

    Moreno, Andres; Joy, Mike; Sutinen, Erkki

    2013-01-01

    Computer generated animations are resources used to explain how programs are executed in order to clarify the relevant programming concepts. However, whilst trying to understand new programming concepts it is not clear how and when students benefit from an animation if they are using the tool on their own. To clarify the role of an animation tool…

  11. Roles of Animation Tools in Understanding Programming Concepts

    Science.gov (United States)

    Moreno, Andres; Joy, Mike; Sutinen, Erkki

    2013-01-01

    Computer generated animations are resources used to explain how programs are executed in order to clarify the relevant programming concepts. However, whilst trying to understand new programming concepts it is not clear how and when students benefit from an animation if they are using the tool on their own. To clarify the role of an animation tool…

  12. Adapting Animal-Assisted Therapy Trials to Prison-Based Animal Programs.

    Science.gov (United States)

    Allison, Molly; Ramaswamy, Megha

    2016-09-01

    Prison-based animal programs have shown promise when it comes to increased sociability, responsibility, and levels of patience for inmates who participate in these programs. Yet there remains a dearth of scientific research that demonstrates the impact of prison-based animal programs on inmates' physical and mental health. Trials of animal-assisted therapy interventions, a form of human-animal interaction therapy most often used with populations affected by depression/anxiety, mental illness, and trauma, may provide models of how prison-based animal program research can have widespread implementation in jail and prison settings, whose populations have high rates of mental health problems. This paper reviews the components of prison-based animal programs most commonly practiced in prisons today, presents five animal-assisted therapy case studies, evaluates them based on their adaptability to prison-based animal programs, and discusses the institutional constraints that act as barriers for rigorous prison-based animal program research implementation. This paper can serve to inform the development of a research approach to animal-assisted therapy that nurses and other public health researchers can use in working with correctional populations.

  13. Rational domain swaps decipher programming in fungal highly reducing polyketide synthases and resurrect an extinct metabolite.

    Science.gov (United States)

    Fisch, Katja M; Bakeer, Walid; Yakasai, Ahmed A; Song, Zhongshu; Pedrick, Jennifer; Wasil, Zahida; Bailey, Andrew M; Lazarus, Colin M; Simpson, Thomas J; Cox, Russell J

    2011-10-19

    The mechanism of programming of iterative highly reducing polyketide synthases remains one of the key unsolved problems of secondary metabolism. We conducted rational domain swaps between the polyketide synthases encoding the biosynthesis of the closely related compounds tenellin and desmethylbassianin. Expression of the hybrid synthetases in Aspergillus oryzae led to the production of reprogrammed compounds in which the changes to the methylation pattern and chain length could be mapped to the domain swaps. These experiments reveal for the first time the origin of programming in these systems. Domain swaps combined with coexpression of two cytochrome P450 encoding genes from the tenellin biosynthetic gene cluster led to the resurrection of the extinct metabolite bassianin.

  14. Computational fluid dynamics model of avian tracheal temperature control as a model for extant and extinct animals.

    Science.gov (United States)

    Sverdlova, N S; Arkali, F; Witzel, U; Perry, S F

    2013-10-01

    Respiratory evaporative cooling is an important mechanism of temperature control in bird. A computational simulation of the breathing cycle, heat and water loss in anatomical avian trachea/air sac model has not previously been conducted. We report a first attempt to simulate a breathing cycle in a three-dimensional model of avian trachea and air sacs (domestic fowl) using transient computational fluid dynamics. The airflow in the trachea of the model is evoked by changing the volume of the air sacs based on the measured tidal volume and inspiratory/expiratory times for the domestic fowl. We compare flow parameters and heat transfer results with in vivo data and with our previously reported results for a two-dimensional model. The total respiratory heat loss corresponds to about 13-19% of the starvation metabolic rate of domestic fowl. The present study can lend insight into a possible thermoregulatory function in species with long necks and/or a very long trachea, as found in swans and birds of paradise. Assuming the structure of the sauropod dinosaur respiratory system was close to avian, the simulation of the respiratory temperature control (using convective and evaporative cooling) in the extensively experimentally studied domestic fowl may also help in making simulations of respiratory heat control in these extinct animals. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. An Approach to Effortless Construction of Program Animations

    Science.gov (United States)

    Velazquez-Iturbide, J. Angel; Pareja-Flores, Cristobal; Urquiza-Fuentes, Jaime

    2008-01-01

    Program animation systems have not been as widely adopted by computer science educators as we might expect from the firm belief that they can help in enhancing computer science education. One of the most notable obstacles to their adoption is the considerable effort that the production of program animations represents for the instructor. We…

  16. An Approach to Effortless Construction of Program Animations

    Science.gov (United States)

    Velazquez-Iturbide, J. Angel; Pareja-Flores, Cristobal; Urquiza-Fuentes, Jaime

    2008-01-01

    Program animation systems have not been as widely adopted by computer science educators as we might expect from the firm belief that they can help in enhancing computer science education. One of the most notable obstacles to their adoption is the considerable effort that the production of program animations represents for the instructor. We…

  17. Sensory extinction and sensory reinforcement principles for programming multiple adaptive behavior change.

    Science.gov (United States)

    Rincover, A; Cook, R; Peoples, A; Packard, D

    1979-01-01

    The role of sensory reinforcement was examined in programming multiple treatment gains in self-stimulation and spontaneous play for developmentally disabled children. Two phases were planned. First, we attempted to identify reinforcers maintaining self-stimulation. Sensory Extinction procedures were implemented in which auditory, proprioceptive, or visual sensory consequences of self-stimulatory behavior were systematically removed and reintroduced in a reversal design. When self-stimulation was decreased or eliminated as a result of removing one of these sensory consequences, the functional sensory consequence was designated as a child's preferred sensory reinforcer. In Phase 2, we assessed whether children would play selectively with toys producing the preferred kind of sensory stimulation. The results showed the following. (1) Self-stimulatory behavior was found to be maintained by sensory reinforcement. When the sensory reinforcer was removed, self-stimulation extinguished. (2) The sensory reinforcers identified for self-stimulatory behavior also served as reinforcers for new, appropriate toy play. (3) The multiple treatment gains observed appeared to be relatively durable in the absence of external reinforcers for play or restraints on self-stimulation. These results illustrate one instance in which multiple behavior change may be programmed in a predictable, lawful fashion by using "natural communities of sensory reinforcement."

  18. Animator

    Science.gov (United States)

    Tech Directions, 2008

    2008-01-01

    Art and animation work is the most significant part of electronic game development, but is also found in television commercials, computer programs, the Internet, comic books, and in just about every visual media imaginable. It is the part of the project that makes an abstract design idea concrete and visible. Animators create the motion of life in…

  19. Regulation of animal experimentation: Canada's program of voluntary control.

    Science.gov (United States)

    Rowsell, H C

    1986-01-01

    The Canadian Council on Animal Care (CCAC), is an autonomous advisory and supervisory body responsible for surveillance of experimental animal care and use in Canada's universities, government laboratories and pharmaceutical houses. Its 20-organization membership includes representatives of government, industry, academia and the humane movement. CCAC's voluntary peer review program depends heavily on institutional animal care committees who evaluate the ethical aspects of animal study protocols, and provide day-to-day surveillance of animal care. Its scientific teams, each of which also includes an appointee of the Canadian Federation of Humane Societies (CFHS), conduct assessments based on CCAC's "Guide to the Care and Use of Experimental Animals" (Volume 1, 1980; Volume 2, 1984). Canada's two major funding agencies, the Medical Research Council (MRC) and the Natural Sciences and Engineering Research Council (NSERC), have recently stated that, in the event of an institution's continued non-compliance with CCAC requirements, sanctions may include the "freezing or withdrawal of any or all research programs funded by either or both Research Councils in an institution". This presentation describes the CCAC program of voluntary peer review and examines historic aspects of animal issues in Canada, from that country's early reliance on the fur trade, to today's almost defunct harp seal fishery, from Banting and Best's discovery of insulin, to development of the pacemaker.

  20. Stress-induced enhancement of fear conditioning and sensitization facilitates extinction-resistant and habituation-resistant fear behaviors in a novel animal model of posttraumatic stress disorder.

    Science.gov (United States)

    Corley, Michael J; Caruso, Michael J; Takahashi, Lorey K

    2012-01-18

    Posttraumatic stress disorder (PTSD) is characterized by stress-induced symptoms including exaggerated fear memories, hypervigilance and hyperarousal. However, we are unaware of an animal model that investigates these hallmarks of PTSD especially in relation to fear extinction and habituation. Therefore, to develop a valid animal model of PTSD, we exposed rats to different intensities of footshock stress to determine their effects on either auditory predator odor fear extinction or habituation of fear sensitization. In Experiment 1, rats were exposed to acute footshock stress (no shock control, 0.4 mA, or 0.8 mA) immediately prior to auditory fear conditioning training involving the pairing of auditory clicks with a cloth containing cat odor. When presented to the conditioned auditory clicks in the next 5 days of extinction testing conducted in a runway apparatus with a hide box, rats in the two shock groups engaged in higher levels of freezing and head out vigilance-like behavior from the hide box than the no shock control group. This increase in fear behavior during extinction testing was likely due to auditory activation of the conditioned fear state because Experiment 2 demonstrated that conditioned fear behavior was not broadly increased in the absence of the conditioned auditory stimulus. Experiment 3 was then conducted to determine whether acute exposure to stress induces a habituation resistant sensitized fear state. We found that rats exposed to 0.8 mA footshock stress and subsequently tested for 5 days in the runway hide box apparatus with presentations of nonassociative auditory clicks exhibited high initial levels of freezing, followed by head out behavior and culminating in the occurrence of locomotor hyperactivity. In addition, Experiment 4 indicated that without delivery of nonassociative auditory clicks, 0.8 mA footshock stressed rats did not exhibit robust increases in sensitized freezing and locomotor hyperactivity, albeit head out vigilance

  1. Authorized Course of Instruction for the Quinmester Program. Science: The World of Animals, Animal Life, Four Legged and Otherwise.

    Science.gov (United States)

    Dade County Public Schools, Miami, FL.

    This instructional package contains three animal life units developed for the Dade County Florida Quinmester Program. "The World of Animals" is a survey course of the animal kingdom (excluding man) and involves the students in many laboratory investigations and group activities. Typical animals of South Florida and unusual animals of the…

  2. History of the Animal Care Program at Johnson Space Center

    Science.gov (United States)

    Khan-Mayberry, Noreen; Bassett, Stephanie

    2010-01-01

    NASA has a rich history of scientific research that has been conducted throughout our numerous manned spaceflight programs. This scientific research has included animal test subjects participating in various spaceflight missions, including most recently, Space Shuttle mission STS-131. The Animal Care Program at Johnson Space Center (JSC) in Houston, Texas is multi-faceted and unique in scope compared to other centers within the agency. The animal care program at JSC has evolved from strictly research to include a Longhorn facility and the Houston Zoo's Attwater Prairie Chicken refuge, which is used to help repopulate this endangered species. JSC is home to more than 300 species of animals including home of hundreds of white-tailed deer that roam freely throughout the center which pose unique issues in regards to population control and safety of NASA workers, visitors and tourists. We will give a broad overview of our day to day operations, animal research, community outreach and protection of animals at NASA Johnson Space Center.

  3. Fossil worm burrows reveal very early terrestrial animal activity and shed light on trophic resources after the end-cretaceous mass extinction.

    Directory of Open Access Journals (Sweden)

    Karen Chin

    Full Text Available The widespread mass extinctions at the end of the Cretaceous caused world-wide disruption of ecosystems, and faunal responses to the one-two punch of severe environmental perturbation and ecosystem collapse are still unclear. Here we report the discovery of in situ terrestrial fossil burrows from just above the impact-defined Cretaceous-Paleogene (K/Pg boundary in southwestern North Dakota. The crisscrossing networks of horizontal burrows occur at the interface of a lignitic coal and silty sandstone, and reveal intense faunal activity within centimeters of the boundary clay. Estimated rates of sedimentation and coal formation suggest that the burrows were made less than ten thousand years after the end-Cretaceous impact. The burrow characteristics are most consistent with burrows of extant earthworms. Moreover, the burrowing and detritivorous habits of these annelids fit models that predict the trophic and sheltering lifestyles of terrestrial animals that survived the K/Pg extinction event. In turn, such detritus-eaters would have played a critical role in supporting secondary consumers. Thus, some of the carnivorous vertebrates that radiated after the K/Pg extinction may owe their evolutionary success to thriving populations of earthworms.

  4. Fossil Worm Burrows Reveal Very Early Terrestrial Animal Activity and Shed Light on Trophic Resources after the End-Cretaceous Mass Extinction

    Science.gov (United States)

    Chin, Karen; Pearson, Dean; Ekdale, A. A.

    2013-01-01

    The widespread mass extinctions at the end of the Cretaceous caused world-wide disruption of ecosystems, and faunal responses to the one-two punch of severe environmental perturbation and ecosystem collapse are still unclear. Here we report the discovery of in situ terrestrial fossil burrows from just above the impact-defined Cretaceous-Paleogene (K/Pg) boundary in southwestern North Dakota. The crisscrossing networks of horizontal burrows occur at the interface of a lignitic coal and silty sandstone, and reveal intense faunal activity within centimeters of the boundary clay. Estimated rates of sedimentation and coal formation suggest that the burrows were made less than ten thousand years after the end-Cretaceous impact. The burrow characteristics are most consistent with burrows of extant earthworms. Moreover, the burrowing and detritivorous habits of these annelids fit models that predict the trophic and sheltering lifestyles of terrestrial animals that survived the K/Pg extinction event. In turn, such detritus-eaters would have played a critical role in supporting secondary consumers. Thus, some of the carnivorous vertebrates that radiated after the K/Pg extinction may owe their evolutionary success to thriving populations of earthworms. PMID:23951041

  5. ANIMAL NUTRITION. PROGRAMMED INSTRUCTION UNITS, ANIMAL NUTRITION, FEED CHARACTERISTICS, VITAMINS, MINERALS. FINAL REPORT NUMBER 12.

    Science.gov (United States)

    LONG, GILBERT A.

    PRINCIPLES AND FACTS NECESSARY FOR EFFECTIVE ANIMAL NUTRITION PRACTICES WERE IDENTIFIED BY EXAMINATION OF RECENT SCIENTIFIC REPORTS. UTILIZING THIS INFORMATION, THE AUTHOR INVOLVED 16 VOCATIONAL AGRICULTURE TEACHERS IN THE DEVELOPMENT AND EXPERIMENTAL USE OF A UNIT OF PROGRAMED LEARNING MATERIALS. INSTRUCTIONAL RESULTS WERE NOT AVAILABLE AT THE…

  6. Animal Science Technology. An Experimental Developmental Program. Volume I, Report of the Developmental Program.

    Science.gov (United States)

    Brant, Herman G.; And Others

    In 1961, administrative personnel at Delhi College in New York observed that formal training programs for animal science technicians were virtually nonexistant. Response to this apparent need resulted in the initiation of perhaps the first 2-year Animal Science Technology Program in the nation. This two-volume report is the result of an extensive…

  7. Animal Science Update Programs--The Role of Teacher Educators.

    Science.gov (United States)

    Osborne, Ed; And Others

    1986-01-01

    Agricultural teachers must continually improve their knowledge and skills in animal science. Teacher educators can play a significant role in this process through the following channels: summer courses, teleconferencing, workshops, summer internships, technical update programs, field days, curriculum materials development and dissemination, and…

  8. Fear Extinction as a Model for Translational Neuroscience: Ten Years of Progress

    OpenAIRE

    Milad, Mohammed R.; Quirk, Gregory J

    2012-01-01

    The psychology of extinction has been studied for decades. Approximately 10 years ago, however, there began a concerted effort to understand the neural circuits of extinction of fear conditioning, in both animals and humans. Progress during this period has been facilitated by an unusual degree of coordination between rodent and human researchers examining fear extinction. This successful research program could serve as a model for translational research in other areas of behavioral neuroscien...

  9. Loss of animal seed dispersal increases extinction risk in a tropical tree species due to pervasive negative density dependence across life stages.

    Science.gov (United States)

    Caughlin, T Trevor; Ferguson, Jake M; Lichstein, Jeremy W; Zuidema, Pieter A; Bunyavejchewin, Sarayudh; Levey, Douglas J

    2015-01-07

    Overhunting in tropical forests reduces populations of vertebrate seed dispersers. If reduced seed dispersal has a negative impact on tree population viability, overhunting could lead to altered forest structure and dynamics, including decreased biodiversity. However, empirical data showing decreased animal-dispersed tree abundance in overhunted forests contradict demographic models which predict minimal sensitivity of tree population growth rate to early life stages. One resolution to this discrepancy is that seed dispersal determines spatial aggregation, which could have demographic consequences for all life stages. We tested the impact of dispersal loss on population viability of a tropical tree species, Miliusa horsfieldii, currently dispersed by an intact community of large mammals in a Thai forest. We evaluated the effect of spatial aggregation for all tree life stages, from seeds to adult trees, and constructed simulation models to compare population viability with and without animal-mediated seed dispersal. In simulated populations, disperser loss increased spatial aggregation by fourfold, leading to increased negative density dependence across the life cycle and a 10-fold increase in the probability of extinction. Given that the majority of tree species in tropical forests are animal-dispersed, overhunting will potentially result in forests that are fundamentally different from those existing now.

  10. Neuronal circuits of fear extinction.

    Science.gov (United States)

    Herry, Cyril; Ferraguti, Francesco; Singewald, Nicolas; Letzkus, Johannes J; Ehrlich, Ingrid; Lüthi, Andreas

    2010-02-01

    Fear extinction is a form of inhibitory learning that allows for the adaptive control of conditioned fear responses. Although fear extinction is an active learning process that eventually leads to the formation of a consolidated extinction memory, it is a fragile behavioural state. Fear responses can recover spontaneously or subsequent to environmental influences, such as context changes or stress. Understanding the neuronal substrates of fear extinction is of tremendous clinical relevance, as extinction is the cornerstone of psychological therapy of several anxiety disorders and because the relapse of maladaptative fear and anxiety is a major clinical problem. Recent research has begun to shed light on the molecular and cellular processes underlying fear extinction. In particular, the acquisition, consolidation and expression of extinction memories are thought to be mediated by highly specific neuronal circuits embedded in a large-scale brain network including the amygdala, prefrontal cortex, hippocampus and brain stem. Moreover, recent findings indicate that the neuronal circuitry of extinction is developmentally regulated. Here, we review emerging concepts of the neuronal circuitry of fear extinction, and highlight novel findings suggesting that the fragile phenomenon of extinction can be converted into a permanent erasure of fear memories. Finally, we discuss how research on genetic animal models of impaired extinction can further our understanding of the molecular and genetic bases of human anxiety disorders.

  11. A Parable of Small Animals and Megafauna Extinction: A Paleo-Economic Theory of Climate Change versus Human Overkill in the Pleistocene

    NARCIS (Netherlands)

    Bulte, E.H.; Horan, R.D.; Shogren, J.F.

    2006-01-01

    After centuries of debate, paleontologists are converging towards the conclusion that human overkill caused the massive extinction of large mammals in the late Pleistocene. This paper revisits the question of megafauna extinction by incorporating economic behavior into the debate. We allow for endog

  12. ADAM: A computer program to simulate selective-breeding schemes for animals

    DEFF Research Database (Denmark)

    Pedersen, L D; Sørensen, A C; Henryon, M

    2009-01-01

    ADAM is a computer program that models selective breeding schemes for animals using stochastic simulation. The program simulates a population of animals and traces the genetic changes in the population under different selective breeding scenarios. It caters to different population structures, gen......, genetic models, selection strategies, and mating designs. ADAM can be used to evaluate breeding schemes and generate genetic data to test statistical tools......ADAM is a computer program that models selective breeding schemes for animals using stochastic simulation. The program simulates a population of animals and traces the genetic changes in the population under different selective breeding scenarios. It caters to different population structures...

  13. Assessing Effectiveness of a Nonhuman Animal Welfare Education Program for Primary School Children.

    Science.gov (United States)

    Hawkins, Roxanne D; Williams, Joanne M

    2017-01-01

    Nonhuman animal welfare education aims to promote positive relationships between children and animals and thus improve animal welfare, yet few scientific evaluations of these programs exist. This study aimed to evaluate the effectiveness of an education program developed by the Scottish Society for the Prevention of Cruelty to Animals (SPCA) that included 4 interventions focusing on pets (companion animals), wild animals, farm animals, and general animal rescues. Knowledge, attachment to pets, and attitudes and beliefs about animal minds were assessed at pretest, posttest, and delayed posttest using a questionnaire administered to 1,217 Scottish children aged 7 to 13 years old. Results showed a significant positive impact of the program on knowledge about animals and the Scottish SPCA for all interventions. The pet and farming interventions significantly impacted children's beliefs about animal minds. There were trends toward improvements in a range of other measures. This study highlights the importance of teaching animal welfare education to children for early prevention of animal cruelty, discusses the need to base this education on theory and research to find effective change, and demonstrates how evidence-based practice can inform future education programs.

  14. InfoVis Interaction Techniques in Animation of Recursive Programs

    Directory of Open Access Journals (Sweden)

    Antonio Pérez-Carrasco

    2010-02-01

    Full Text Available Algorithm animations typically assist in educational tasks aimed simply at achieving understanding. Potentially, animations could assist in higher levels of cognition, such as the analysis level, but they usually fail in providing this support because they are not flexible or comprehensive enough. In particular, animations of recursion provided by educational systems hardly support the analysis of recursive algorithms. Here we show how to provide full support to the analysis of recursive algorithms. From a technical point of view, animations are enriched with interaction techniques inspired by the information visualization (InfoVis field. Interaction tasks are presented in seven categories, and deal with both static visualizations and dynamic animations. All of these features are implemented in the SRec system, and visualizations generated by SRec are used to illustrate the article.

  15. Winter population numbers [Fort Niobrara NWR fenced animal program

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This data set is for winter population numbers for bison, elk and longhorn from January 1st of the calendar year and is part of the Fort Niobrara Fenced Animal...

  16. Minireview: Epigenetic Programming of Diabetes and Obesity: Animal Models

    National Research Council Canada - National Science Library

    Seki, Yoshinori; Williams, Lyda; Vuguin, Patricia M; Charron, Maureen J

    2012-01-01

    .... Animal models of epigenetic modifications secondary to an altered IU milieu are an invaluable tool to study the mechanisms that determine the development of metabolic diseases, such as diabetes and obesity...

  17. Compound Stimulus Extinction Reduces Spontaneous Recovery in Humans

    Science.gov (United States)

    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…

  18. The History of the Animal Care Program at NASA Johnson Space Center

    Science.gov (United States)

    Khan-Mayberry, Noreen; Bassett, Stephanie

    2010-01-01

    This slide presentation reviews the work of the Animal Care Program (ACP). Animals have been used early in space exploration to ascertain if it were possible to launch a manned spacecraft. The program is currently involved in many studies that assist in enhancing the scientific knowledge of the effect of space travel. The responsibilities of the ACP are: (1) Organize and supervise animal care operations & activities (research, testing & demonstration). (2) Maintain full accreditation by the International Association for the Assessment and Accreditation of Laboratory Animal Care (AAALAC) (3) Ensure protocol compliance with IACUC recommendations (4) Training astronauts for in-flight animal experiments (5) Maintain accurate & timely records for all animal research testing approved by JSC IACUC (6) Organize IACUC meetings and assist IACUC members (7) Coordinate IACUC review of the Institutional Program for Humane Care and Use of Animals (every 6 mos)

  19. Chronic stress disrupts fear extinction and enhances amygdala and hippocampal Fos expression in an animal model of post-traumatic stress disorder.

    Science.gov (United States)

    Hoffman, Ann N; Lorson, Nickolaus G; Sanabria, Federico; Foster Olive, M; Conrad, Cheryl D

    2014-07-01

    Chronic stress may impose a vulnerability to develop maladaptive fear-related behaviors after a traumatic event. Whereas previous work found that chronic stress impairs the acquisition and recall of extinguished fear, it is unknown how chronic stress impacts nonassociative fear, such as in the absence of the conditioned stimulus (CS) or in a novel context. Male rats were subjected to chronic stress (STR; wire mesh restraint 6 h/d/21d) or undisturbed (CON), then tested on fear acquisition (3 tone-footshock pairings), and two extinction sessions (15 tones/session) within the same context. Then each group was tested (6 tones) in the same context (SAME) or a novel context (NOVEL), and brains were processed for functional activation using Fos immunohistochemistry. Compared to CON, STR showed facilitated fear acquisition, resistance to CS extinction on the first extinction day, and robust recovery of fear responses on the second extinction day. STR also showed robust freezing to the context alone during the first extinction day compared to CON. When tested in the same or a novel context, STR exhibited higher freezing to context than did CON, suggesting that STR-induced fear was independent of context. In support of this, STR showed increased Fos-like expression in the basolateral amygdala and CA1 region of the hippocampus in both the SAME and NOVEL contexts. Increased Fos-like expression was also observed in the central amygdala in STR-NOVEL vs. CON-NOVEL. These data demonstrate that chronic stress enhances fear learning and impairs extinction, and affects nonassociative processes as demonstrated by enhanced fear in a novel context.

  20. Exploring Animal-Assisted Programs with Children in School and Therapeutic Contexts

    Science.gov (United States)

    Friesen, Lori

    2010-01-01

    Animal-Assisted programs with children are becoming increasingly popular in school and therapeutic settings. This article provides an overview of the benefits accrued by children as well as the concerns with programs which involve animals, and therapy dogs in particular, in these environments. Research over the past 30 years indicates that therapy…

  1. Animals

    Energy Technology Data Exchange (ETDEWEB)

    Skuterud, L.; Strand, P. [Norwegian Radiation Protection Authority (Norway); Howard, B.J. [Inst. of Terrestrial Ecology (United Kingdom)

    1997-10-01

    The radionuclides of most concern with respect to contamination of animals after a nuclear accident are radioiodine, radiocaesium and radiostrontium (ICRP 30, 1979). Of the other significant anthropogenic radionuclides likely to be released in most accidents, only small proportions of that ingested will be absorbed in an animals gut, and the main animal products, milk and meat, will not normally be contaminated to a significant extent. Animal products will mostly be contaminated as a result of ingestion of contaminated feed and possibly, but to a much lesser extent, from inhalation (for radioiodine only). Direct external contamination of animals is of little or no consequence in human food production. Radioiodine and radiostrontium are important with respect to contamination of milk; radiocaesium contaminates both milk and meat. The physical and chemical form of a radionuclide can influence its absorption in the animal gut. For example, following the Chernobyl accident radiocaesium incorporated into vegetation by root uptake was more readily absorbed than that associated with the original deposit. The transfer of radiocaesium and radiostrontium to animals will be presented both as transfer coefficients and aggregated transfer coefficients. For most animal meat products, only radiocaesium is important as other radionuclides do not significantly contaminate muscle. Farm animal products are the most important foodstuff determining radiocaesium intake by the average consumer in the Nordic countries. The major potential source of radioiodine and radiostrontium to humans is milk and milk products. Of the different species, the smaller animals have the highest transfer of radiocaesium from fodder to meat and milk. (EG). 68 refs.

  2. 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 occu

  3. S-R Associations, Their Extinction, and Recovery in an Animal Model of Anxiety: A New Associative Account of Phobias Without Recall of Original Trauma

    Science.gov (United States)

    Laborda, Mario A.; Miller, Ralph R.

    2012-01-01

    Associative accounts of the etiology of phobias have been criticized because of numerous cases of phobias in which the client does not remember a relevant traumatic event (i.e., Pavlovian conditioning trial), instructions, or vicarious experience with the phobic object. In three lick suppression experiments with rats as subjects, we modeled an associative account of such fears. Experiment 1 assessed stimulus-response (S-R) associations in first-order fear conditioning. After behaviorally complete devaluation of the unconditioned stimulus, the target stimulus still produced strong conditioned responses, suggesting that an S-R association had been formed and that this association was not significantly affected when the outcome was devalued through unsignaled presentations of the unconditioned stimulus. Experiments 2 and 3 examined extinction and recovery of S-R associations. Experiment 2 showed that extinguished S-R associations returned when testing occurred outside of the extinction context (i.e., renewal) and Experiment 3 found that a long delay between extinction and testing also produced a return of the extinguished S-R associations (i.e., spontaneous recovery). These experiments suggest that fears for which people cannot recall a cause are explicable in an associative framework, and indicate that those fears are susceptible to relapse after extinction treatment just like stimulus-outcome (S-O) associations. PMID:21496503

  4. Minireview: Epigenetic programming of diabetes and obesity: animal models.

    Science.gov (United States)

    Seki, Yoshinori; Williams, Lyda; Vuguin, Patricia M; Charron, Maureen J

    2012-03-01

    A growing body of evidence suggests that the intrauterine (IU) environment has a significant and lasting effect on the long-term health of the growing fetus and the development of metabolic disease in later life as put forth in the fetal origins of disease hypothesis. Metabolic diseases have been associated with alterations in the epigenome that occur without changes in the DNA sequence, such as cytosine methylation of DNA, histone posttranslational modifications, and micro-RNA. Animal models of epigenetic modifications secondary to an altered IU milieu are an invaluable tool to study the mechanisms that determine the development of metabolic diseases, such as diabetes and obesity. Rodent and nonlitter bearing animals are good models for the study of disease, because they have similar embryology, anatomy, and physiology to humans. Thus, it is feasible to monitor and modify the IU environment of animal models in order to gain insight into the molecular basis of human metabolic disease pathogenesis. In this review, the database of PubMed was searched for articles published between 1999 and 2011. Key words included epigenetic modifications, IU growth retardation, small for gestational age, animal models, metabolic disease, and obesity. The inclusion criteria used to select studies included animal models of epigenetic modifications during fetal and neonatal development associated with adult metabolic syndrome. Experimental manipulations included: changes in the nutritional status of the pregnant female (calorie-restricted, high-fat, or low-protein diets during pregnancy), as well as the father; interference with placenta function, or uterine blood flow, environmental toxin exposure during pregnancy, as well as dietary modifications during the neonatal (lactation) as well as pubertal period. This review article is focused solely on studies in animal models that demonstrate epigenetic changes that are correlated with manifestation of metabolic disease, including diabetes

  5. 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;…

  6. Animal Antics. Program Guide for the Texas Reading Club, 1987.

    Science.gov (United States)

    Larson, Jeanette

    Developed for the Texas Reading Club, a program sponsored cooperatively by local libraries and the Texas State Library and designed to encourage children and their parents to read and to use the library, this guide is intended to inspire program ideas, including activities, crafts, books, and audiovisuals, appropriate to the Reading Club's 1987…

  7. Coordination of Programs on Domestic Animal Genomics: The Federal Framework

    Science.gov (United States)

    2004-06-01

    agriculture. Following the identification of the diagnosis of this animal, U.S. beef market prices dropped precipitously, due to pressure imposed by the...impact, such as the avian flu outbreak in Asia, North America, and Europe, and prion diseases such as BSE in cattle, scrapie in sheep and chronic

  8. Mixtures Equation Pilot Program to Reduce Animal Testing

    Science.gov (United States)

    EPA is announcing the start of a pilot program to evaluate the usefulness and acceptability of a mathematical tool (the GHS Mixtures Equation), which is used in the Globally Harmonized System of Classification and Labeling of Chemicals (GHS).

  9. Minireview: Epigenetic Programming of Diabetes and Obesity: Animal Models

    OpenAIRE

    2012-01-01

    A growing body of evidence suggests that the intrauterine (IU) environment has a significant and lasting effect on the long-term health of the growing fetus and the development of metabolic disease in later life as put forth in the fetal origins of disease hypothesis. Metabolic diseases have been associated with alterations in the epigenome that occur without changes in the DNA sequence, such as cytosine methylation of DNA, histone posttranslational modifications, and micro-RNA. Animal models...

  10. The animal economy as object and program in Montpellier vitalism.

    Science.gov (United States)

    Wolfe, Charles T; Terada, Motoichi

    2008-12-01

    Our aim in this paper is to show the importance of the notion of éonomie animale in Montpellier vitalism as a hybrid concept which brings together the structural and functional dimensions of the living body--dimensions which hitherto had primarily been studied according to a mechanistic model, or were discussed within the framework of Stahlian animism. The celebrated image of the bee-swarm expresses this structural-functional understanding of living bodies quite well: "One sees them press against each other, mutually supporting each other, forming a kind of whole, in which each living part, in its own way, by means of the correspondence and directions of its motions, enables this kind of life to be sustained in the body" (Ménuret 1765c, Enc. XI, 319a). What is important here is that every component part is always a living part, i.e., every structural unit is always functional. Interestingly, while the twin notions of "animal economy" and organisation are presented as improvements over a mechanistic perspective, they are nonetheless compatible with an expanded sense of mechanism, and by extension, with materialism as reflected notably in the writings of Ménuret and Bordeu. We thus propose both a revision and reconstruction of the historical status of the "animal economy," and a reflection on its conceptual status.

  11. Animals

    Institute of Scientific and Technical Information of China (English)

    杨光

    2000-01-01

    The largest animal ever to live on the earth is the blue whale(蓝鲸)It weighs about 80 tons--more than 24 elephants. It is more than 30 metres long. A newborn baby whale weighs as much as a big elephant.

  12. Olecranon orientation as an indicator of elbow joint angle in the stance phase, and estimation of forelimb posture in extinct quadruped animals.

    Science.gov (United States)

    Fujiwara, Shin-Ichi

    2009-09-01

    Reconstruction of limb posture is a challenging task in assessing functional morphology and biomechanics of extinct tetrapods, mainly because of the wide range of motions possible at each limb joint and because of our poor knowledge of the relationship between posture and musculoskeletal structure, even in the extant taxa. This is especially true for extinct mammals such as the desmostylian taxa Desmostylus and Paleoparadoxia. This study presents a procedure that how the elbow joint angles of extinct quadruped mammals can be inferred from osteological characteristics. A survey of 67 dried skeletons and 113 step cycles of 32 extant genera, representing 25 families and 13 orders, showed that the olecranon of the ulna and the shaft of the humerus were oriented approximately perpendicular to each other during the stance phase. At this angle, the major extensor muscles maximize their torque at the elbow joint. Based on this survey, I suggest that olecranon orientation can be used for inferring the elbow joint angles of quadruped mammals with prominent olecranons, regardless of taxon, body size, and locomotor guild. By estimating the elbow joint angle, it is inferred that Desmostylus would have had more upright forelimbs than Paleoparadoxia, because their elbow joint angles during the stance phase were approximately 165 degrees and 130 degrees , respectively. Difference in elbow joint angles between these two genera suggests possible differences in stance and gait of these two mammals.

  13. Preservation of Natural Diversity: The Problem of Extinction Prone Species

    Science.gov (United States)

    Terborgh, John

    1974-01-01

    Examines threatened extinction of birds and recommends agencies adopt policies which minimize the pace of extinctions through the setting aside of large preserves which protect natural vegetation formation and the animal life. (BR)

  14. Programming Digital Stories and How-to Animations

    Science.gov (United States)

    Hansen, Alexandria Killian; Iveland, Ashley; Harlow, Danielle Boyd; Dwyer, Hilary; Franklin, Diana

    2015-01-01

    As science teachers continue preparing for implementation of the "Next Generation Science Standards," one recommendation is to use computer programming as a promising context to efficiently integrate science and engineering. In this article, a interdisciplinary team of educational researchers and computer scientists describe how to use…

  15. Programming Digital Stories and How-to Animations

    Science.gov (United States)

    Hansen, Alexandria Killian; Iveland, Ashley; Harlow, Danielle Boyd; Dwyer, Hilary; Franklin, Diana

    2015-01-01

    As science teachers continue preparing for implementation of the "Next Generation Science Standards," one recommendation is to use computer programming as a promising context to efficiently integrate science and engineering. In this article, a interdisciplinary team of educational researchers and computer scientists describe how to use…

  16. ANIMALS

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Mammals(哺乳动物)Mammals are the world's most dominant(最占优势的)animal.They are extremely(非常)diverse(多种多样的)creatures(生物,动物)that include(包括)the biggest ever animal (the blue whale鲸,which eats up to 6 tons every day),the smallest(leaf-nosed bat小蹄蝠) and the laziest(sloth树獭,who spends 80% of their time sleeping).There are over 4,600 kinds of mammals and they live in very different environments(环境)—oceans(海洋),rivers,the jungle(丛林),deserts,and plains(平原).

  17. Animal Models and Bone Histomorphometry: Translational Research for the Human Research Program

    Science.gov (United States)

    Sibonga, Jean D.

    2010-01-01

    This slide presentation reviews the use of animal models to research and inform bone morphology, in particular relating to human research in bone loss as a result of low gravity environments. Reasons for use of animal models as tools for human research programs include: time-efficient, cost-effective, invasive measures, and predictability as some model are predictive for drug effects.

  18. Interstellar Extinction

    Science.gov (United States)

    Gontcharov, G. A.

    2016-12-01

    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 brought us closer to an understanding of the distribution of the dust particles on scales of the Galaxy and the universe. We are in the midst of a scientific revolution in our understanding of the interstellar medium and dust. Progress in, and the key results of, this revolution are still difficult to predict. Nevertheless, (a) a physically justified model has been developed for the spatial distribution of absorbing material over the nearest few kiloparsecs, including the Gould belt as a dust container, which gives an accurate estimate of the extinction for any object just by its galactic coordinates. It is also clear that (b) the interstellar medium contains roughly half the mass of matter in the galactic vicinity of the solar system (the other half is made up of stars, their remnants, and dark matter) and (c) the interstellar medium and, especially, dust, differ substantially in different regions of space and deep space cannot be understood by only studying near space.

  19. Developing a Comprehensive Animal Care Occupational Health and Safety Program at a Land-Grant Institution.

    Science.gov (United States)

    Goodly, Lyndon J; Jarrell, Vickie L; Miller, Monica A; Banks, Maureen C; Anderson, Thomas J; Branson, Katherine A; Woodward, Robert T; Peper, Randall L; Myers, Sara J

    2016-01-01

    The Public Health Service Policy on the Humane Care and Use of Laboratory Animals and sound ethical practices require institutions to provide safe working environments for personnel working with animals; this mandate is achieved in part by establishing an effective animal care Occupational Health and Safety Program (OHSP). Land-grant institutions often face unique organizational challenges in fulfilling this requirement. For example, responsibilities for providing health and safety programs often have historically been dispersed among many different divisions scattered around the campus. Here we describe how our institutional management personnel overcame organizational structure and cultural obstacles during the formation of a comprehensive campus-wide animal care OHSP. Steps toward establishing the animal care OHSP included assigning overall responsibility, identifying all stakeholders, creating a leadership group, and hiring a fulltime Animal Care OHSP Specialist. A web-based portal was developed, implemented, and refined over the past 7 y and reflected the unique organizational structures of the university and the needs of our research community. Through this web-based portal, hazards are identified, risks are assessed, and training is provided. The animal care OHSP now provides easy mandatory enrollment, supports timely feedback regarding hazards, and affords enrollees the opportunity to participate in voluntary medical surveillance. The future direction and development of the animal care OHSP will be based on the research trends of campus, identification of emerging health and safety hazards, and ongoing evaluation and refinement of the program.

  20. Educators' Curriculum Guide. Quality Assurance and Animal Care: Youth Education Program.

    Science.gov (United States)

    Busboom, Jan R.; Newman, Jerry A.; Shulaw, William P.; Jeffreys, J. Bradford

    This curriculum guide contains a six-unit, two-level program combining animal science and veterinary care for youth club leaders and members in grades three through twelve. The Facilitator and Educator/Leader Introductions describe the program, the goals, and the students who will participate. The six lesson plans contain what the lesson is about,…

  1. Development of a Regional Cooperative Off-Campus Education Program in Food Animal Medicine.

    Science.gov (United States)

    Frank, Floyd W.; Lincoln, Stuart D.

    1979-01-01

    The University of Idaho, in cooperation with the Washington, Oregon, and Idaho (WOI) Regional Program in Veterinary Medicine, developed an off-campus facility for the study of food animal medicine. The objectives, design, and program of the regional center are described. (BH)

  2. 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.

  3. 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.

  4. Differences in Moral Judgment on Animal and Human Ethics Issues between University Students in Animal-Related, Human Medical and Arts Programs.

    Science.gov (United States)

    Verrinder, Joy M; Ostini, Remo; Phillips, Clive J C

    2016-01-01

    Moral judgment in relation to animal ethics issues has rarely been investigated. Among the research that has been conducted, studies of veterinary students have shown greater use of reasoning based on universal principles for animal than human ethics issues. This study aimed to identify if this was unique to students of veterinary and other animal-related professions. The moral reasoning of first year students of veterinary medicine, veterinary technology, and production animal science was compared with that of students in non-animal related disciplines of human medicine and arts. All students (n = 531) completed a moral reasoning test, the VetDIT, with animal and human scenarios. When compared with reasoning on human ethics issues, the combined group of students evaluating animal ethics issues showed higher levels of Universal Principles reasoning, lower levels of Personal Interest reasoning and similar levels of Maintaining Norms reasoning. Arts students showed more personal interest reasoning than students in most animal-related programs on both animal and human ethics issues, and less norms-based reasoning on animal ethics issues. Medical students showed more norms-based reasoning on animal ethics issues than all of the animal-related groups. There were no differences in principled reasoning on animal ethics issues between program groups. This has implications for animal-related professions and education programs showing that students' preference for principled reasoning on animal ethics issues is not unique to animal-related disciplines, and highlighting the need to develop student (and professional) capacity to apply principled reasoning to address ethics issues in animal industries to reduce the risk of moral distress.

  5. Endangered Species and Natural Resource Exploitation: Extinction vs. Coexistence

    OpenAIRE

    Tsur, Yacov; Zemel, Amos

    1994-01-01

    The threat on the survival of animal species due to intensive use of natural resources is incorporated within resource management models, paying special attention to uncertainty regarding the conditions that lead to extinction. The manner in which the potential benefits forgone due to the species extinction (denoted extinction penalty) induce more conservative exploitation policies is studied in detail. When the extinction penalty is ignored, the optimal policy is to drive the resource stock ...

  6. Infectious Disease, Endangerment, and Extinction

    Directory of Open Access Journals (Sweden)

    Ross D. E. MacPhee

    2013-01-01

    Full Text Available 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.

  7. Animal Health Technicians: A Survey of Program Graduates and of Veterinarians.

    Science.gov (United States)

    Barsaleau, Richard B.; Walters, Henry R.

    This document compiles the reports of two surveys conducted by Cosumnes River College to determine the status of graduates of its Animal Health Technician program, and to assess the acceptance and use of such paraprofessionals by area veterinarians. Information concerning type of employment, state certification, salaries, types of duties, length…

  8. SNPs genotyping technologies and their applications in farm animals breeding programs: review

    Directory of Open Access Journals (Sweden)

    Hamed Kharrati Koopaee

    2014-02-01

    Full Text Available Single nucleotide polymorphisms (SNPs are DNA sequence variations that occur when a single nucleotide: adenine (A, thymine (T, cytosine (C or guanine (G in the genome sequence is altered. Traditional and high throughput methods are two main strategies for SNPs genotyping. The SNPs genotyping technologies provide powerful resources for animal breeding programs.Genomic selection using SNPs is a new tool for choosing the best breeding animals. In addition, the high density maps using SNPs can provide useful genetic tools to study quantitative traits genetic variations. There are many sources of SNPs and exhaustive numbers of methods of SNP detection to be considered. For many traits in farm animals, the rate of genetic improvement can be nearly doubled when SNPs information is used compared to the current methods of genetic evaluation. The goal of this review is to characterize the SNPs genotyping methods and their applications in farm animals breeding.

  9. Perceptions of a hospital-based animal assisted intervention program: An exploratory study.

    Science.gov (United States)

    Abrahamson, Kathleen; Cai, Yun; Richards, Elizabeth; Cline, Krista; O'Haire, Marguerite E

    2016-11-01

    Research has shown that there are multiple benefits of animal assisted interventions for patients. However, the impact of interaction with these animals in staff is understudied, particularly in the acute care setting, and is thus a novel contribution to the literature on human-animal interaction. The purpose of this qualitative pilot study was to contribute to the body of knowledge surrounding the experiences and perceptions of hospital staff who have participated in a hospital-based animal assisted intervention program. Nine face-to-face semi-structured interviews were conducted (4 staff nurses, 3 support staff members, and 2 hospital volunteers). Five themes emerged from the respondent interviews: (1) descriptions of the therapy dogs; (2) contacts with the dogs at work; (3) connection with the dogs outside of work; (4) benefits; (5) drawbacks. Our findings reflect abundantly positive hospital staff experiences.

  10. The Rochester Checkers Player: Multi-Model Parallel Programming for Animate Vision

    Science.gov (United States)

    1991-06-01

    parallel programming is likely to serve for all tasks, however. Early vision algorithms are intensely data parallel, often utilizing fine-grain parallel computations that share an image, while cognition algorithms decompose naturally by function, often consisting of loosely-coupled, coarse-grain parallel units. A typical animate vision application will likely consist of many tasks, each of which may require a different parallel programming model, and all of which must cooperate to achieve the desired behavior. These multi-model programs require an

  11. Polyandry prevents extinction.

    Science.gov (United States)

    Price, Tom A R; Hurst, Greg D D; Wedell, Nina

    2010-03-09

    Females of most animal species are polyandrous, with individual females usually mating with more than one male. However, the ubiquity of polyandry remains enigmatic because of the potentially high costs to females of multiple mating. Current theory to account for the high prevalence of polyandry largely focuses on its benefits to individual females. There are also higher-level explanations for the high incidence of polyandry-polyandrous clades may speciate more rapidly. Here we test the hypothesis that polyandry may also reduce population extinction risk. We demonstrate that mating with multiple males protects populations of the fruit fly Drosophila pseudoobscura against extinction caused by a "selfish" sex-ratio-distorting element. Thus, the frequency of female multiple mating in nature may be associated not only with individual benefits to females of this behavior but also with increased persistence over time of polyandrous species and populations. Furthermore, we show that female remating behavior can determine the frequency of sex-ratio distorters in populations. This may also be true for many other selfish genetic elements in natural populations.

  12. Developmental programming: the concept, large animal models, and the key role of uteroplacental vascular development.

    Science.gov (United States)

    Reynolds, L P; Borowicz, P P; Caton, J S; Vonnahme, K A; Luther, J S; Hammer, C J; Maddock Carlin, K R; Grazul-Bilska, A T; Redmer, D A

    2010-04-01

    Developmental programming refers to the programming of various bodily systems and processes by a stressor of the maternal system during pregnancy or during the neonatal period. Such stressors include nutritional stress, multiple pregnancy (i.e., increased numbers of fetuses in the gravid uterus), environmental stress (e.g., high environmental temperature, high altitude, prenatal steroid exposure), gynecological immaturity, and maternal or fetal genotype. Programming refers to impaired function of numerous bodily systems or processes, leading to poor growth, altered body composition, metabolic dysfunction, and poor productivity (e.g., poor growth, reproductive dysfunction) of the offspring throughout their lifespan and even across generations. A key component of developmental programming seems to be placental dysfunction, leading to altered fetal growth and development. We discuss various large animal models of developmental programming and how they have and will continue to contribute to our understanding of the mechanisms underlying altered placental function and developmental programming, and, further, how large animal models also will be critical to the identification and application of therapeutic strategies that will alleviate the negative consequences of developmental programming to improve offspring performance in livestock production and human medicine.

  13. Programs to improve production and consumption of animal source foods and malnutrition in Vietnam.

    Science.gov (United States)

    Hop, Le Thi

    2003-11-01

    The objective of this paper is to review programs to improve production of animal source foods in Vietnam, emphasizing the VAC ecosystem and trends in undernutrition during past decades. The food consumption surveys of the Vietnamese population in 1985 showed that food intake was inadequate, especially animal protein. Most protein came from rice; the consumption of meats, beans and fish was negligible. During the last 10 y, much attention was paid to improving the health and nutritional status of the Vietnamese people. Many programs were implemented in Vietnam to improve the food intake and nutritional status of the people, and especially the intake of animal source foods. The VAC system is a traditional type of farming for Vietnamese people. The aim of VAC is to provide diversified agricultural products to meet the complex nutritional demands of man. Based on the scientific fundamentals of VAC, many different models of VAC have been developed at a national level. The intervention programs to improve production and consumption of animal source foods, and the VAC ecosystem in Vietnam during the last decade have been successful. The population's dietary intakes have clearly improved in terms of both quality and quantity. The consumption of staple foods in 2000, including meats, fish, fats and oils, and ripe fruits was much higher compared to 1987. The prevalence of undernutrition in children old, and of chronic energy deficiency (CED) in women of reproductive age, has been remarkably reduced.

  14. The National Research Initiative Competitive Grants Program in animal reproduction: changes in priorities and scope relevant to United States animal agriculture.

    Science.gov (United States)

    Mirando, M A

    2007-03-01

    The National Research Initiative (NRI) Competitive Grants Program is the USDA's major competitive grants program and is administered by the Cooperative State Research, Education, and Extension Service. The NRI was authorized by the US Congress in the 1990 Farm Bill at a funding level of $500 million; however, the maximal NRI appropriation was $181.17 million in fiscal year (FY) 2006. Across all programs, the NRI is mandated to use 40% of its funding to support mission-linked research. Since its inception in 1991, the NRI has funded competitive grants in the discipline of animal reproduction. Before 2004, the Animal Reproduction Program funded a broad range of projects encompassing almost every subdiscipline in reproductive biology of farm animals, including aquatic species important to the aquaculture industry and laboratory animals. During FY 2004, the NRI Animal Reproduction Program narrowed the focus of its funding priorities to 5 issue-based topics in an effort to make greater measurable improvements in a few high-impact areas over the next 10 years. Funding priorities were narrowed further in FY 2006 to 3 subdisciplines based, in part, on recommendations that emerged from a stakeholder workshop conducted by Cooperative State Research, Education, and Extension Service in August 2004. In FY 2003, Congress authorized expenditure of up to 20% of the funds appropriated to the NRI to support projects that integrate at least 2 of the 3 functions of research, education, and extension. In FY 2004, the Animal Reproduction Program included a funding priority for integrated projects focused primarily on infertility in dairy cattle. The program funded its first integrated project in FY 2005. During FY 2002, increased emphasis on justification for the use of model systems (e.g., laboratory animals and in vitro systems) was included in the NRI request for applications. In FY 2006, applications proposing to primarily utilize nonagricultural animal models were excluded from

  15. 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.

  16. Periodicity of extinction: A 1988 update

    Science.gov (United States)

    Sepkowski, J. John, Jr.

    1988-01-01

    The hypothesis that events of mass extinction recur periodically at approximately 26 my intervals is an empirical claim based on analysis of data from the fossil record. The hypothesis has become closely linked with catastrophism because several events in the periodic series are associated with evidence of extraterrestrial impacts, and terrestrial forcing mechanisms with long, periodic recurrences are not easily conceived. Astronomical mechanisms that have been hypothesized include undetected solar companions and solar oscillation about the galactic plane, which induce comet showers and result in impacts on Earth at regular intervals. Because these mechanisms are speculative, they have been the subject of considerable controversy, as has the hypothesis of periodicity of extinction. In response to criticisms and uncertainties, a data base was developed on times of extinction of marine animal genera. A time series is given and analyzed with 49 sample points for the per-genus extinction rate from the Late Permian to the Recent. An unexpected pattern in the data is the uniformity of magnitude of many of the periodic extinction events. Observations suggest that the sequence of extinction events might be the result of two sets of mechanisms: a periodic forcing that normally induces only moderate amounts of extinction, and independent incidents or catastrophes that, when coincident with the periodic forcing, amplify its signal and produce major-mass extinctions.

  17. Extinction as the loss of evolutionary history

    OpenAIRE

    Erwin, Douglas H.

    2008-01-01

    Current plant and animal diversity preserves at most 1–2% of the species that have existed over the past 600 million years. But understanding the evolutionary impact of these extinctions requires a variety of metrics. The traditional measurement is loss of taxa (species or a higher category) but in the absence of phylogenetic information it is difficult to distinguish the evolutionary depth of different patterns of extinction: the same species loss can encompass very different losses of evolu...

  18. Compound stimulus extinction reduces spontaneous recovery in humans

    Science.gov (United States)

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

    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 paired with an electric shock. The target CS (CSA) was extinguished alone followed by compound presentations of the extinguished CSA and nonextinguished CSB. Recovery of conditioned skin conductance responses to CSA was reduced 24 h after compound extinction, as compared with a group who received an equal number of extinction trials to the CSA alone. PMID:26572649

  19. Animal investigation program 1978 annual report: Nevada Test Site and vicinity

    Energy Technology Data Exchange (ETDEWEB)

    Smith, D D; Bernhardt, D E; Giles, K R

    1980-12-01

    Data are presented from the radioanalyses of tissues collected from cattle, mule deer, desert bighorn sheep, rabbits, golden eagles, and other wildlife that resided on or near the Nevada Test Site during 1978. Routine and special activities of the Animal Investigation Program are also discussed. Other than the naturally occurring Potassium-40, gamma-emitting radionuclides were detected infrequently with the exception of short-lived radionuclides found in samples from animals collected soon after March 14 (the date of a nuclear test by the People's Republic of China). Strontium-90 concentrations in bones from deer, cattle, and desert bighorn sheep were consistent with those of recent years. Tritium concentrations were generally within expected environmental limits with the exception of animals exposed to sources of contamination; e.g., drainage ponds from Area 12 tunnels. Plutonium levels in all tissues from all species showed little variation from recent years. However, cattle tissue sampled in the fall were higher than those collected in the spring. Radionuclide tissue concentrations were generally higher in the tissues of animals residing in Area 15 than in similar animals collected from other Nevada Test Site areas. Hypothetical dose estimates to man were calculated on the basis of the daily consumption of 0.5 kilogram of liver or muscle from animals that contained peak radionuclide levels. The movements of 13 mule deer outfitted with collars containing a radio transmitter unit were monitored on a weekly basis. No gross or microscopic lesions were found in necropsied animals that could be directly attributed to the effects of ionizing radiation.

  20. Fetal programming of CVD and renal disease: animal models and mechanistic considerations.

    Science.gov (United States)

    Langley-Evans, Simon C

    2013-08-01

    The developmental origins of health and disease hypothesis postulates that exposure to a less than optimal maternal environment during fetal development programmes physiological function, and determines risk of disease in adult life. Much evidence of such programming comes from retrospective epidemiological cohorts, which demonstrate associations between birth anthropometry and non-communicable diseases of adulthood. The assertion that variation in maternal nutrition drives these associations is supported by studies using animal models, which demonstrate that maternal under- or over-nutrition during pregnancy can programme offspring development. Typically, the offspring of animals that are undernourished in pregnancy exhibit a relatively narrow range of physiological phenotypes that includes higher blood pressure, glucose intolerance, renal insufficiency and increased adiposity. The observation that common phenotypes arise from very diverse maternal nutritional insults has led to the proposal that programming is driven by a small number of mechanistic processes. The remodelling of tissues during development as a consequence of maternal nutritional status being signalled by endocrine imbalance or key nutrients limiting processes in the fetus may lead to organs having irreversibly altered structures that may limit their function with ageing. It has been proposed that the maternal diet may impact upon epigenetic marks that determine gene expression in fetal tissues, and this may be an important mechanism connecting maternal nutrient intakes to long-term programming of offspring phenotype. The objective for this review is to provide an overview of the mechanistic basis of fetal programming, demonstrating the critical role of animal models as tools for the investigation of programming phenomena.

  1. Is extinction forever?

    Science.gov (United States)

    Smith-Patten, Brenda D; Bridge, Eli S; Crawford, Priscilla H C; Hough, Daniel J; Kelly, Jeffrey F; Patten, Michael A

    2015-05-01

    Mistrust of science has seeped into public perception of the most fundamental aspect of conservation-extinction. The term ought to be straightforward, and yet, there is a disconnect between scientific discussion and public views. This is not a mere semantic issue, rather one of communication. Within a population dynamics context, we say that a species went locally extinct, later to document its return. Conveying our findings matters, for when we use local extinction, an essentially nonsensical phrase, rather than extirpation, which is what is meant, then we contribute to, if not create outright, a problem for public understanding of conservation, particularly as local extinction is often shortened to extinction in media sources. The public that receives the message of our research void of context and modifiers comes away with the idea that extinction is not forever or, worse for conservation as a whole, that an extinction crisis has been invented.

  2. A framework program for the teaching of alternative methods (replacement, reduction, refinement) to animal experimentation.

    Science.gov (United States)

    Daneshian, Mardas; Akbarsha, Mohammad A; Blaauboer, Bas; Caloni, Francesca; Cosson, Pierre; Curren, Rodger; Goldberg, Alan; Gruber, Franz; Ohl, Frauke; Pfaller, Walter; van der Valk, Jan; Vinardell, Pilar; Zurlo, Joanne; Hartung, Thomas; Leist, Marcel

    2011-01-01

    Development of improved communication and education strategies is important to make alternatives to the use of animals, and the broad range of applications of the 3Rs concept better known and understood by different audiences. For this purpose, the Center for Alternatives to Animal Testing in Europe (CAAT-Europe) together with the Transatlantic Think Tank for Toxicology (t(4)) hosted a three-day workshop on "Teaching Alternative Methods to Animal Experimentation". A compilation of the recommendations by a group of international specialists in the field is summarized in this report. Initially, the workshop participants identified the different audience groups to be addressed and also the communication media that may be used. The main outcome of the workshop was a framework for a comprehensive educational program. The modular structure of the teaching program presented here allows adaptation to different audiences with their specific needs; different time schedules can be easily accommodated on this basis. The topics cover the 3Rs principle, basic research, toxicological applications, method development and validation, regulatory aspects, case studies and ethical aspects of 3Rs approaches. This expert consortium agreed to generating teaching materials covering all modules and providing them in an open access online repository.

  3. A comparison between nuclear dismantling during plant and animal programmed cell death.

    Science.gov (United States)

    Domínguez, Fernando; Cejudo, Francisco Javier

    2012-12-01

    Programmed cell death (PCD) is a process of organized destruction of cells, essential for the development and maintenance of cellular homeostasis of multicellular organisms. Cells undergoing PCD begin a degenerative process in response to internal or external signals, whereby the nucleus becomes one of the targets. The process of nuclear dismantling includes events affecting the nuclear envelope, such as formation of lobes at the nuclear surface, selective proteolysis of nucleoporins and nuclear pore complex clustering. In addition, chromatin condensation increases in coordination with DNA fragmentation. These processes have been largely studied in animals, but remain poorly understood in plants. The overall process of cell death has different morphological and biochemical features in plants and animals. However, recent advances suggest that nuclear dismantling in plant cells progresses with morphological and biochemical characteristics similar to those in apoptotic animal cells. In this review, we summarize nuclear dismantling in plant PCD, focusing on the similarities and differences with their animal counterparts. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  4. Campylobacter species in animal, food, and environmental sources, and relevant testing programs in Canada.

    Science.gov (United States)

    Huang, Hongsheng; Brooks, Brian W; Lowman, Ruff; Carrillo, Catherine D

    2015-10-01

    Campylobacter species, particularly thermophilic campylobacters, have emerged as a leading cause of human foodborne gastroenteritis worldwide, with Campylobacter jejuni, Campylobacter coli, and Campylobacter lari responsible for the majority of human infections. Although most cases of campylobacteriosis are self-limiting, campylobacteriosis represents a significant public health burden. Human illness caused by infection with campylobacters has been reported across Canada since the early 1970s. Many studies have shown that dietary sources, including food, particularly raw poultry and other meat products, raw milk, and contaminated water, have contributed to outbreaks of campylobacteriosis in Canada. Campylobacter spp. have also been detected in a wide range of animal and environmental sources, including water, in Canada. The purpose of this article is to review (i) the prevalence of Campylobacter spp. in animals, food, and the environment, and (ii) the relevant testing programs in Canada with a focus on the potential links between campylobacters and human health in Canada.

  5. Interactive computerized learning program exposes veterinary students to challenging international animal-health problems.

    Science.gov (United States)

    Conrad, Patricia A; Hird, Dave; Arzt, Jonathan; Hayes, Rick H; Magliano, Dave; Kasper, Janine; Morfin, Saul; Pinney, Stephen

    2007-01-01

    This article describes a computerized case-based CD-ROM (CD) on international animal health that was developed to give veterinary students an opportunity to "virtually" work alongside veterinarians and other veterinary students as they try to solve challenging disease problems relating to tuberculosis in South African wildlife, bovine abortion in Mexico, and neurologic disease in horses in Rapa Nui, Chile. Each of the three case modules presents, in a highly interactive format, a problem or mystery that must be solved by the learner. As well as acquiring information via video clips and text about the specific health problem, learners obtain information about the different countries, animal-management practices, diagnostic methods, related disease-control issues, economic factors, and the opinions of local experts. After assimilating this information, the learner must define the problem and formulate an action plan or make a recommendation or diagnosis. The computerized program invokes three principles of adult education: active learning, learner-centered education, and experiential learning. A medium that invokes these principles is a potentially efficient learning tool and template for developing other case-based problem-solving computerized programs. The program is accessible on the World Wide Web at International_web/international_menu.html>. A broadband Internet connection is recommended, since the modules make extensive use of embedded video and audio clips. Information on how to obtain the CD is also provided.

  6. 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...... started at around 40,000 years ago. On continents, large mammals (especially those >50 kg body mass) were affected, while on islands, the impacts were mainly felt by birds. The causes of these extinctions are not well known but hunting, habitat alteration and the introduction of non-native species...... reasons (certain groups do not fossilize) and methodological problems (methods of excavation and identification). Consequently, we can only crudely estimate the current rate of extinction. Nonetheless, it is evident that humans generated a new mass extinction, affecting all species in all habitats, and...

  7. 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...... started at around 40,000 years ago. On continents, large mammals (especially those >50 kg body mass) were affected, while on islands, the impacts were mainly felt by birds. The causes of these extinctions are not well known but hunting, habitat alteration and the introduction of non-native species...... are the main causes of extinction. Our knowledge about extinctions is very incomplete, due to bias in research by taxonomy (vertebrate groups are better studied), geography (northern areas have received more attention), habitat (terrestrial habitats are better known than marine ones), as well as biological...

  8. Evaluating the presence versus absence of the reinforcer during extinction.

    Science.gov (United States)

    Castillo, Mariana I; Borrero, John C; Mendres-Smith, Amber E

    2014-01-01

    The purpose of this study was to assess the effects of extinction when the reinforcer was present versus absent. These effects were examined with 2 human operant procedures (i.e., a computer program and a mechanical apparatus) with college students as participants. Discriminable properties of the apparatus appeared to influence responding during extinction. In general, responding during extinction was less likely with the mechanical apparatus when the reinforcer was absent and more likely with the computer program.

  9. 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.

  10. Compound stimulus extinction reduces spontaneous recovery in humans

    OpenAIRE

    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 paired with an electric shock. The target CS (CSA) was extinguished alone followed by compound presentations of the extinguished CSA and nonextinguished CSB. Reco...

  11. Cannabinoid facilitation of fear extinction memory recall in humans

    Science.gov (United States)

    Rabinak, Christine A.; Angstadt, Mike; Sripada, Chandra S.; Abelson, James L.; Liberzon, Israel; Milad, Mohammed R.; Phan, K. Luan

    2012-01-01

    A first-line approach to treat anxiety disorders is exposure-based therapy, which relies on extinction processes such as repeatedly exposing the patient to stimuli (conditioned stimuli; CS) associated with the traumatic, fear-related memory. However, a significant number of patients fail to maintain their gains, partly attributed to the fact that this inhibitory learning and its maintenance is temporary and conditioned fear responses can return. Animal studies have shown that activation of the cannabinoid system during extinction learning enhances fear extinction and its retention. Specifically, CB1 receptor agonists, such as Δ9-tetrahydrocannibinol (THC), can facilitate extinction recall by preventing recovery of extinguished fear in rats. However, this phenomenon has not been investigated in humans. We conducted a study using a randomized, double-blind, placebo-controlled, between-subjects design, coupling a standard Pavlovian fear extinction paradigm and simultaneous skin conductance response (SCR) recording with an acute pharmacological challenge with oral dronabinol (synthetic THC) or placebo (PBO) 2 hours prior to extinction learning in 29 healthy adult volunteers (THC = 14; PBO = 15) and tested extinction retention 24 hours after extinction learning. Compared to subjects that received PBO, subjects that received THC showed low SCR to a previously extinguished CS when extinction memory recall was tested 24 hours after extinction learning, suggesting that THC prevented the recovery of fear. These results provide the first evidence that pharmacological enhancement of extinction learning is feasible in humans using cannabinoid system modulators, which may thus warrant further development and clinical testing. PMID:22796109

  12. 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.

  13. 78 FR 69602 - Foreign Supplier Verification Programs for Importers of Food for Humans and Animals; Extension of...

    Science.gov (United States)

    2013-11-20

    ... HUMAN SERVICES Food and Drug Administration 21 CFR Part 1 RIN 0910-AG64 Foreign Supplier Verification... entitled ``Foreign Supplier Verification Programs for Importers of Food for Humans and Animals'' that... 45730), we published a proposed rule entitled ``Foreign Supplier Verification Programs for Importers...

  14. A Guide for Planning Facilities for Occupational Preparation Programs in Laboratory Animal Science Technology. Interim Report. Research 27.

    Science.gov (United States)

    Colling, Walter E.; Farnsworth, Wilbur M.

    The major purpose of this guide is to elicit the necessary information for the writing of educational specifications for facilities to house career programs in laboratory animal science technology. The guide is also designed to: (1) assist planners in formation of creative solutions to the housing of desired educational programs, (2) prevent…

  15. Equine-Facilitated Prison-Based Programs within the Context of Prison-Based Animal Programs: State of the Science Review

    Science.gov (United States)

    Bachi, Keren

    2013-01-01

    Equine-facilitated prison programs have become more prevalent and operate in correctional facilities in 13 states throughout the United States. However, there is a deficit of empirical knowledge to guide them. This article reviews 19 studies of prison-based animal programs and centers on patterns in the literature. It reveals how previous studies…

  16. 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…

  17. Memory Retrieval before or after Extinction Reduces Recovery of Fear in Adolescent Rats

    Science.gov (United States)

    Baker, Kathryn D.; McNally, Gavan P.; Richardson, Rick

    2013-01-01

    Adolescent rats exhibit impaired extinction retention compared to pre-adolescent and adult rats. A single nonreinforced exposure to the conditioned stimulus (CS; a retrieval trial) given shortly before extinction has been shown in some circumstances to reduce the recovery of fear after extinction in adult animals. This study investigated whether a…

  18. Forming Competing Fear Learning and Extinction Memories in Adolescence Makes Fear Difficult to Inhibit

    Science.gov (United States)

    Baker, Kathryn D.; Richardson, Rick

    2015-01-01

    Fear inhibition is markedly impaired in adolescent rodents and humans. The present experiments investigated whether this impairment is critically determined by the animal's age at the time of fear learning or their age at fear extinction. Male rats (n = 170) were tested for extinction retention after conditioning and extinction at different ages.…

  19. Forming Competing Fear Learning and Extinction Memories in Adolescence Makes Fear Difficult to Inhibit

    Science.gov (United States)

    Baker, Kathryn D.; Richardson, Rick

    2015-01-01

    Fear inhibition is markedly impaired in adolescent rodents and humans. The present experiments investigated whether this impairment is critically determined by the animal's age at the time of fear learning or their age at fear extinction. Male rats (n = 170) were tested for extinction retention after conditioning and extinction at different ages.…

  20. Memory Retrieval before or after Extinction Reduces Recovery of Fear in Adolescent Rats

    Science.gov (United States)

    Baker, Kathryn D.; McNally, Gavan P.; Richardson, Rick

    2013-01-01

    Adolescent rats exhibit impaired extinction retention compared to pre-adolescent and adult rats. A single nonreinforced exposure to the conditioned stimulus (CS; a retrieval trial) given shortly before extinction has been shown in some circumstances to reduce the recovery of fear after extinction in adult animals. This study investigated whether a…

  1. Photosensitive seizures provoked while viewing "pocket monsters," a made-for-television animation program in Japan.

    Science.gov (United States)

    Ishida, S; Yamashita, Y; Matsuishi, T; Ohshima, M; Ohshima, H; Kato, H; Maeda, H

    1998-12-01

    To describe the recent epidemic of photosensitive seizure that occurred in relation to an episode of the television animation program "Pocket Monsters," we report four patients who experienced seizures while watching the episode in question. We also report some technical aspects of the program episode. We investigated the clinical symptoms of the four patients and performed routine EEGs with intermittent photic stimulation (IPS). If IPS provoked no photoparoxysmal response (PPR) during the routine EEG examination, a second EEG was performed with the photic stimulator placed 10 cm from the patient's eyes. In addition, we reviewed the "Pocket Monsters" episode, focusing our attention on the visual techniques used with reference to the Independent Television Commission (ITC) guidelines. One patient who had myoclonic jerks before the convulsion in question was diagnosed as having juvenile myoclonic epilepsy, and the diagnosis of another patient was pure photosensitive epilepsy. The remaining two patients had their first seizures, which could be occasional seizures, and we therefore could not reach a diagnosis of epilepsy. In our four patients, only one showed PPR on the routine EEG. Two patients revealed PPR on the second EEG, and the remaining patient showed no PPR. Rapid changes in color are believed to be responsible for the photosensitive seizures because all four patients had seizures at around 18:50, when seconds of deep red and bright blue flashes, alternating at a frequency of 12 Hz, were shown. Regulations for technical aspects of children's programming, including the use of colors, are urgently needed in Japan to prevent a repeated incident. In addition, the IPS procedure needs to be standardized, especially for patients who are suspected to have photosensitivity.

  2. Forming competing fear learning and extinction memories in adolescence makes fear difficult to inhibit

    OpenAIRE

    Baker, Kathryn D.; Richardson, Rick

    2015-01-01

    Fear inhibition is markedly impaired in adolescent rodents and humans. The present experiments investigated whether this impairment is critically determined by the animal's age at the time of fear learning or their age at fear extinction. Male rats (n = 170) were tested for extinction retention after conditioning and extinction at different ages. We examined neural correlates of impaired extinction retention by detection of phosphorylated mitogen-activated protein kinase immunoreactivity (pMA...

  3. The Memory System Engaged During Acquisition Determines the Effectiveness of Different Extinction Protocols

    OpenAIRE

    Jarid eGoodman; Mark ePackard

    2015-01-01

    Previous research indicates that extinction of rodent maze behavior may occur without explicit performance of the previously required response. In latent extinction, confining an animal to a previously rewarded goal location without reinforcement is typically sufficient to produce extinction of maze learning. However, previous studies have not determined whether latent extinction may be successfully employed to extinguish all types of memory acquired in the maze, or whether only specific typ...

  4. Context-Dependent Human Extinction Memory Is Mediated by a Ventromedial Prefrontal and Hippocampal Network

    OpenAIRE

    Kalisch, R; Korenfeld, E; Stephan, K.E.; Weiskopf, N.; Seymour, B; Dolan, R.J.

    2006-01-01

    In fear extinction, an animal learns that a conditioned stimulus (CS) no longer predicts a noxious stimulus [unconditioned stimulus (UCS)] to which it had previously been associated, leading to inhibition of the conditioned response (CR). Extinction creates a new CS-noUCS memory trace, competing with the initial fear (CS-UCS) memory. Recall of extinction memory and, hence, CR inhibition at later CS encounters is facilitated by contextual stimuli present during extinction training. In line wit...

  5. Systemic blockade of D2-like dopamine receptors facilitates extinction of conditioned fear in mice

    OpenAIRE

    Ponnusamy, Ravikumar; Nissim, Helen A.; Barad, Mark

    2005-01-01

    Extinction of conditioned fear in animals is the explicit model of behavior therapy for human anxiety disorders, including panic disorder, obsessive-compulsive disorder, and post-traumatic stress disorder. Based on previous data indicating that fear extinction in rats is blocked by quinpirole, an agonist of dopamine D2 receptors, we hypothesized that blockade of D2 receptors might facilitate extinction in mice, while agonists should block extinction, as they do in rats. One day after fear con...

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

    NARCIS (Netherlands)

    Powers, M.B.; Smits, J.A.J.; Otto, M.W.; Sanders, C.; Emmelkamp, P.M.G.

    2009-01-01

    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

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

    NARCIS (Netherlands)

    Powers, M.B.; Smits, J.A.J.; Otto, M.W.; Sanders, C.; Emmelkamp, P.M.G.

    2009-01-01

    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

  8. 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.

  9. Early programing of uterine tissue by bisphenol A: Critical evaluation of evidence from animal exposure studies.

    Science.gov (United States)

    Suvorov, Alexander; Waxman, David J

    2015-11-01

    Exposure to Bisphenol A (BPA) during the critical window of uterine development has been proposed to program the uterus for increased disease susceptibility based on well-documented effects of the potent xenoestrogen diethylstilbestrol. To investigate this proposal, we reviewed 37 studies of prenatal and/or perinatal BPA exposure in animal models and evaluated evidence for: molecular signatures of early BPA exposure; the development of adverse uterine health effects; and epigenetic changes linked to long-term dysregulation of uterine gene expression and health effects. We found substantial evidence for adult uterine effects of early BPA exposure. In contrast, experimental support for epigenetic actions of early BPA exposure is very limited, and largely consists of effects on Hoxa gene DNA methylation. Critical knowledge gaps were identified, including the need to fully characterize short-term and long-term uterine gene responses, interactions with estrogens and other endogenous hormones, and any long-lasting epigenetic signatures that impact adult disease. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Endangered Species. Management Improvements Could Enhance Recovery Program. Report to the Chairman, Subcommittee on Fisheries and Wildlife Conservation and the Environment, Committee on Merchant Marine and Fisheries, House of Representatives.

    Science.gov (United States)

    General Accounting Office, Washington, DC. Resources, Community, and Economic Development Div.

    Extinction of animal and plant species has become a serious problem that threatens to become more acute in coming years. The endangered species program was established to prevent further extinctions and ultimately recover species designated as threatened or endangered through the development and implementation of species recovery plans. Concerned…

  11. Endangered Animals. Second Grade.

    Science.gov (United States)

    Popp, Marcia

    This second grade teaching unit centers on endangered animal species around the world. Questions addressed are: What is an endangered species? Why do animals become extinct? How do I feel about the problem? and What can I do? Students study the definition of endangered species and investigate whether it is a natural process. They explore topics…

  12. 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; Muzzio, Isabel A

    2015-06-17

    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.

  13. Hybridization and extinction.

    Science.gov (United States)

    Todesco, Marco; Pascual, Mariana A; Owens, Gregory L; Ostevik, Katherine L; Moyers, Brook T; Hübner, Sariel; Heredia, Sylvia M; Hahn, Min A; Caseys, Celine; Bock, Dan G; Rieseberg, Loren H

    2016-08-01

    Hybridization may drive rare taxa to extinction through genetic swamping, where the rare form is replaced by hybrids, or by demographic swamping, where population growth rates are reduced due to the wasteful production of maladaptive hybrids. Conversely, hybridization may rescue the viability of small, inbred populations. Understanding the factors that contribute to destructive versus constructive outcomes of hybridization is key to managing conservation concerns. Here, we survey the literature for studies of hybridization and extinction to identify the ecological, evolutionary, and genetic factors that critically affect extinction risk through hybridization. We find that while extinction risk is highly situation dependent, genetic swamping is much more frequent than demographic swamping. In addition, human involvement is associated with increased risk and high reproductive isolation with reduced risk. Although climate change is predicted to increase the risk of hybridization-induced extinction, we find little empirical support for this prediction. Similarly, theoretical and experimental studies imply that genetic rescue through hybridization may be equally or more probable than demographic swamping, but our literature survey failed to support this claim. We conclude that halting the introduction of hybridization-prone exotics and restoring mature and diverse habitats that are resistant to hybrid establishment should be management priorities.

  14. Stressor controllability modulates fear extinction in humans.

    Science.gov (United States)

    Hartley, Catherine A; Gorun, Alyson; Reddan, Marianne C; Ramirez, Franchesca; Phelps, Elizabeth A

    2014-09-01

    Traumatic events are proposed to play a role in the development of anxiety disorders, however not all individuals exposed to extreme stress experience a pathological increase in fear. Recent studies in animal models suggest that the degree to which one is able to control an aversive experience is a critical factor determining its behavioral consequences. In this study, we examined whether stressor controllability modulates subsequent conditioned fear expression in humans. Participants were randomly assigned to an escapable stressor condition, a yoked inescapable stressor condition, or a control condition involving no stress exposure. One week later, all participants underwent fear conditioning, fear extinction, and a test of extinction retrieval the following day. Participants exposed to inescapable stress showed impaired fear extinction learning and increased fear expression the following day. In contrast, escapable stress improved fear extinction and prevented the spontaneous recovery of fear. Consistent with the bidirectional controllability effects previously reported in animal models, these results suggest that one's degree of control over aversive experiences may be an important factor influencing the development of psychological resilience or vulnerability in humans.

  15. Effects of sleep on memory for conditioned fear and fear extinction

    Science.gov (United States)

    Pace-Schott, Edward F.; Germain, Anne; Milad, Mohammed R.

    2015-01-01

    Learning and memory for extinction of conditioned fear is a basic mammalian mechanism for regulating negative emotion. Sleep promotes both the consolidation of memory and the regulation of emotion. Sleep can influence consolidation and modification of memories associated with both fear and its extinction. After brief overviews of the behavior and neural circuitry associated with fear conditioning, extinction learning and extinction memory in the rodent and human, interactions of sleep with these processes will be examined. Animal and human studies suggest that sleep can serve to consolidate both fear and extinction memory. In humans, sleep also promotes generalization of extinction memory. Time-of-day effects on extinction learning and generalization are also seen. REM may be a sleep stage of particular importance for the consolidation of both fear and extinction memory as evidenced by selective REM deprivation experiments. REM sleep is accompanied by selective activation of the same limbic structures implicated in the learning and memory of fear and extinction. Preliminary evidence also suggests extinction learning can take place during slow wave sleep. Study of low-level processes such as conditioning, extinction and habituation may allow sleep effects on emotional memory to be identified and inform study of sleep’s effects on more complex, emotionally salient declarative memories. Anxiety disorders are marked by impairments of both sleep and extinction memory. Improving sleep quality may ameliorate anxiety disorders by strengthening naturally acquired extinction. Strategically timed sleep may be used to enhance treatment of anxiety by strengthening therapeutic extinction learned via exposure therapy. PMID:25894546

  16. Ecological model of extinctions

    CERN Document Server

    Abramson, G

    1997-01-01

    We present numerical results based on a simplified ecological system in evolution, showing features of extinction similar to that claimed for the biosystem on Earth. In the model each species consists of a population in interaction with the others, that reproduces and evolves in time. Each species is simultaneously a predator and a prey in a food chain. Mutations that change the interactions are supposed to occur randomly at a low rate. Extinctions of populations result naturally from the predator-prey dynamics. The model is not pinned in a fitness variable, and natural selection arises from the dynamics.

  17. Animal Science Technology. An Experimental Developmental Program. Volume II, Curriculum Course Outlines.

    Science.gov (United States)

    Brant, Herman G.

    This volume, the second of a two part evaluation report, is devoted exclusively to the presentation of detailed course outlines representing an Animal Science Technology curriculum. Arranged in 6 terms of study (2 academic years), outlines are included on such topics as: (1) Introductory Animal Science, (2) General Microbiology, (3) Zoonoses, (4)…

  18. Context, Learning, and Extinction

    Science.gov (United States)

    Gershman, Samuel J.; Blei, David M.; Niv, Yael

    2010-01-01

    A. Redish et al. (2007) proposed a reinforcement learning model of context-dependent learning and extinction in conditioning experiments, using the idea of "state classification" to categorize new observations into states. In the current article, the authors propose an interpretation of this idea in terms of normative statistical inference. They…

  19. Unexpectedly many extinct hominins.

    Science.gov (United States)

    Bokma, Folmer; van den Brink, Valentijn; Stadler, Tanja

    2012-09-01

    Recent studies indicate that Neanderthal and Denisova hominins may have been separate species, while debate continues on the status of Homo floresiensis. The decade-long debate between "splitters," who recognize over 20 hominin species, and "lumpers," who maintain that all these fossils belong to just a few lineages, illustrates that we do not know how many extinct hominin species to expect. Here, we present probability distributions for the number of speciation events and the number of contemporary species along a branch of a phylogeny. With estimates of hominin speciation and extincton rates, we then show that the expected total number of extinct hominin species is 8, but may be as high as 27. We also show that it is highly unlikely that three very recent species disappeared due to natural, background extinction. This may indicate that human-like remains are too easily considered distinct species. Otherwise, the evidence suggesting that Neanderthal and the Denisova hominin represent distinct species implies a recent wave of extinctions, ostensibly driven by the only survivor, H. sapiens. © 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.

  20. Extinction of fear is facilitated by social presence: Synergism with prefrontal oxytocin.

    Science.gov (United States)

    Brill-Maoz, Naama; Maroun, Mouna

    2016-04-01

    This study addressed the question of whether extinction in pairs would have a beneficial effect on extinction of fear conditioning. To that end, we established an experimental setting for extinction in which we trained animals to extinguish contextual fear memory in pairs. Taking advantage of the role of oxytocin (OT) in the medial prefrontal cortex (mPFC) in the mediation of memory extinction and social interaction, we also sought to study its role in social interaction-induced effects on extinction. Our results clearly show that the social presence of another animal in the extinction context facilitates extinction, and that this facilitation is mediated through mPFC-OT. Our results suggest that social interaction may be a positive regulator of fear inhibition, implying that social interaction may be an easy, accessible therapeutic tool for the treatment of fear-associated disorders.

  1. Ecology: Dynamics of Indirect Extinction.

    Science.gov (United States)

    Montoya, Jose M

    2015-12-01

    The experimental identification of the mechanism by which extinctions of predators trigger further predator extinctions emphasizes the role of indirect effects between species in disturbed ecosystems. It also has deep consequences for the hidden magnitude of the current biodiversity crisis.

  2. Animal Personality and Mate Preference in American Mink

    DEFF Research Database (Denmark)

    Noer, Christina Lehmkuhl

    are unsustainable. Often, prescribed pairs of animals appear to be incompatible and reproductively unsuccessful. This is also a problem in solitary carnivore species, many of which are threatened with extinction. A suggested solution to this problem is to investigate, which male cues and signals the females use......Conservation-breeding programs in zoos are essential for the management of threatened species. By moving animals amongst institutions for prescribed breeding, these programs aim to promote demographic stability and preserve genetic variation in the captive populations. Yet many breeding programs...... or cues: olfactory (urine and faeces), size, and behaviour. The latter may represent aspects of animal personality. The background for this is explained in the introduction (Chapter I). In Chapter II, a published article, I present a novel study on aspects of animal personality in the American mink...

  3. Mass Extinctions Past and Present.

    Science.gov (United States)

    Allmon, Warren Douglas

    1987-01-01

    Discusses some parallels that seem to exist between mass extinction recognizable in the geologic record and the impending extinction of a significant proportion of the earth's species due largely to tropical deforestation. Describes some recent theories of causal factors and periodicities in mass extinction. (Author/TW)

  4. Extinction of drug seeking: Neural circuits and approaches to augmentation.

    Science.gov (United States)

    McNally, Gavan P

    2014-01-01

    Extinction training can reduce drug seeking behavior. This article reviews the neural circuits that contribute to extinction and approaches to enhancing the efficacy of extinction. Extinction of drug seeking depends on cortical-striatal-hypothalamic and cortical-hypothalamic-thalamic pathways. These pathways interface, in the hypothalamus and thalamus respectively, with the neural circuits controlling reinstatement of drug seeking. The actions of these pathways at lateral hypothalamic orexin neurons, and of perifornical/dorsomedial hypothalamic derived opioid peptides at kappa opioid receptors in the paraventricular thalamus, are important for inhibiting drug seeking. Despite effectively reducing or inhibiting drug seeking in the short term, extinguished drug seeking is prone to relapse. Three different strategies to augment extinction learning or retrieval are reviewed: pharmacological augmentation, retrieval - extinction training, and provision of extinction memory retrieval cues. These strategies have been used in animal models and with human drug users to enhance extinction or cue exposure treatments. They hold promise as novel strategies to promote abstinence from drug seeking. This article is part of a Special Issue entitled 'NIDA 40th Anniversary Issue'.

  5. Animal Models for Small for Gestational Age and Fetal Programing of Adult Disease

    OpenAIRE

    2007-01-01

    Fetal growth retardation is a fetal adaptation in response to inadequate supply of oxygen and/or nutrients. Animal models of intrauterine growth retardation are an invaluable tool to question the genetic, molecular and cellular events that determine fetal growth and development. Rodent and non-litter bearing animals are mammalian system with similar embryology, anatomy and physiology to humans. Utilization of these systems has led to a greater understanding of the pathophysiology and conseque...

  6. Impaired fear extinction learning and cortico-amygdala circuit abnormalities in a common genetic mouse strain

    OpenAIRE

    Hefner, Kathryn; Whittle, Nigel; Juhasz, Jaynann; Norcross, Maxine; Karlsson, Rose-Marie; Saksida, Lisa M.; Bussey, Timothy J.; Singewald, Nicolas; Holmes, Andrew

    2008-01-01

    Fear extinction is a form of new learning that results in the inhibition of conditioned fear. Trait deficits in fear extinction are a risk factor for anxiety disorders. There are few examples of naturally-occurring animal models of impaired extinction. The present study compared fear extinction in a panel of inbred mouse strains. This strain survey revealed an impairment in fear extinction in 129/SvImJ (129S1). The phenotypic specificity of this deficit was evaluated by comparing 129S1 and C5...

  7. Fear extinction as a model for translational neuroscience: ten years of progress.

    Science.gov (United States)

    Milad, Mohammed R; Quirk, Gregory J

    2012-01-01

    The psychology of extinction has been studied for decades. Approximately 10 years ago, however, there began a concerted effort to understand the neural circuits of extinction of fear conditioning, in both animals and humans. Progress during this period has been facilitated by a high degree of coordination between rodent and human researchers examining fear extinction. Here we review the major advances and highlight new approaches to understanding and exploiting fear extinction. Research in fear extinction could serve as a model for translational research in other areas of behavioral neuroscience.

  8. Establishment of an operating room committee and a training program to improve aseptic techniques for rodent and large animal surgery.

    Science.gov (United States)

    Héon, Hélène; Rousseau, Nathalie; Montgomery, Jane; Beauregard, Gilles; Choiniére, Manon

    2006-11-01

    Investigators of our research facility generally accept the concept of asepsis as an important component of adequate surgical care for animals. However, they experience difficulties putting it into practice, especially in the case of rodents. The reasons for this are inconvenience, cost, and lack of training. To better assist investigators in the implementation of aseptic surgical techniques in their laboratories, we have created an Operating Room (OR) Committee modeled after OR committees found in human hospitals. A reconstructive surgeon, a veterinarian, a research scientist, a nurse involved in the training of OR personnel, interns, graduate students, and an animal health technician were chosen as committee members in light of their OR and animal care expertise. The first task of the OR Committee was to establish institutional guidelines for aseptic surgery, taking into account the costs imposed on research budgets by these procedures. The OR Committee also supports a complete training program in aseptic surgery techniques, which consists of lectures, a training manual, videos, and a practical course. Furthermore, when experimental procedures require specialized equipment, the OR Committee collaborates with researchers to develop strategies to achieve asepsis. This OR Committee and the training program proved to be important tools to promote and improve the quality of animal care during surgery.

  9. Use of animals with partially known ancestries in scientifically managed breeding programs.

    Science.gov (United States)

    Willis, Kevin; Lacy, Robert C

    2016-07-01

    Animals with only partially known ancestry present a problem for population managers because it can be difficult to determine their relative genetic value to the population. So long as their ancestry is not completely unknown, population management software such as PMx can calculate a mean kinship for these animals, but that mean kinship is calculated such that there is no decrease in relative genetic value or "penalty" for only partially known ancestry. However, there is a longer-term genetic cost to having animals with only partially known ancestry in the population, and thus it is appropriate to "penalize" animals with partially known ancestry to some extent. The challenge is determining the correct "penalty" which will serve to decrease the percent unknown ancestry in subsequent generations while not causing excessive selection against the known ancestry of the animal. A new parameter of relative genetic value is developed which takes into account both an animal's mean kinship as well as its percent known ancestry. The method used in PMx to calculate the mean kinships also in general overestimates the inbreeding coefficients of offspring of animals with partially known ancestry when the known parents share a common ancestor, but can underestimate inbreeding if common ancestors exist within the unknown portion of the pedigree. This may result in population managers selecting less suitable pairs for breeding in an attempt to avoid an apparent higher level of inbreeding. A parameter is developed that adjusts the inbreeding coefficient to more accurately reflect the likely inbreeding coefficient of potential offspring. Zoo Biol. 35:319-325, 2016. © 2016 Wiley Periodicals, Inc.

  10. Developing Children's Awareness of the Human-Animal Bond: An Assessment of the Experiences and Benefits that Children Receive in the United Animal Nation's Humane Education Ambassador Readers (HEAR) Program

    Science.gov (United States)

    Stokes, Laura

    2009-01-01

    In 2007, the United Animal Nations (UAN) launched the Humane Education Ambassador Readers (HEAR), an innovation that focused on mitigation of animal suffering through education. In the HEAR program, adult volunteers read carefully selected story books to children in grades 3-6 in schools or other educational settings, and hold discussions with the…

  11. Adulthood Animal Abuse among Women Court-Referred to Batterer Intervention Programs

    Science.gov (United States)

    Febres, Jeniimarie; Shorey, Ryan C.; Brasfield, Hope; Zucosky, Heather C.; Ninnemann, Andrew; Elmquist, Joanna; Bucossi, Meggan M.; Andersen, Shawna M.; Schonbrun, Yael C.; Stuart, Gregory L.

    2012-01-01

    The substantial increase in the enrollment of women in batterer intervention programs (BIPs) over the past 30 years has greatly outpaced research on women who perpetrate intimate partner violence (IPV). As a result, it is unknown whether existing programs, which were originally designed to treat male perpetrators, are effective at preventing…

  12. ACM SIGGRAPH Video Review Issue 152, SIGGRAPH 2005 Animation Theater Program PART 2

    DEFF Research Database (Denmark)

    2005-01-01

    Pre-operative evaluation of surgical strategies is of utmost importancein many areas of surgery. This is especially true for surgeryin congenital heart disease, where the complex morphology variesfrom individual to individual. This animation shows how interactive,real-time computer graphics is em...

  13. Pointer Animation Implementation at Development of Multimedia Learning of Java Programming

    Science.gov (United States)

    Rusli, Muhammad; Atmojo, Yohanes Priyo

    2015-01-01

    This research represents the development research using the references of previous research results related to the development of interactive multimedia learning (learner controlled), specially about the effectiveness and efficiency of multimedia learning of a content that developed by pointer animation implementation showing the content in…

  14. Epigenetics and developmental programming of welfare and production traits in farm animals.

    Science.gov (United States)

    Sinclair, K D; Rutherford, K M D; Wallace, J M; Brameld, J M; Stöger, R; Alberio, R; Sweetman, D; Gardner, D S; Perry, V E A; Adam, C L; Ashworth, C J; Robinson, J E; Dwyer, C M

    2016-07-21

    The concept that postnatal health and development can be influenced by events that occur in utero originated from epidemiological studies in humans supported by numerous mechanistic (including epigenetic) studies in a variety of model species. Referred to as the 'developmental origins of health and disease' or 'DOHaD' hypothesis, the primary focus of large-animal studies until quite recently had been biomedical. Attention has since turned towards traits of commercial importance in farm animals. Herein we review the evidence that prenatal risk factors, including suboptimal parental nutrition, gestational stress, exposure to environmental chemicals and advanced breeding technologies, can determine traits such as postnatal growth, feed efficiency, milk yield, carcass composition, animal welfare and reproductive potential. We consider the role of epigenetic and cytoplasmic mechanisms of inheritance, and discuss implications for livestock production and future research endeavours. We conclude that although the concept is proven for several traits, issues relating to effect size, and hence commercial importance, remain. Studies have also invariably been conducted under controlled experimental conditions, frequently assessing single risk factors, thereby limiting their translational value for livestock production. We propose concerted international research efforts that consider multiple, concurrent stressors to better represent effects of contemporary animal production systems.

  15. Animal learning.

    Science.gov (United States)

    Castro, Leyre; Wasserman, Edward A

    2010-01-01

    Pavlov and Thorndike pioneered the experimental study of animal learning and provided psychologists with powerful tools to unveil its underlying mechanisms. Today's research developments and theoretical analyses owe much to the pioneering work of these early investigators. Nevertheless, in the evolution of our knowledge about animal learning, some initial conceptions have been challenged and revised. We first review the original experimental procedures and findings of Pavlov and Thorndike. Next, we discuss critical research and consequent controversies which have greatly shaped animal learning theory. For example, although contiguity seemed to be the only condition that is necessary for learning, we now know that it is not sufficient; the conditioned stimulus (CS) also has to provide information about the occurrence of the unconditioned stimulus (US). Also, animals appear to learn different things about the same stimuli when circumstances vary. For instance, when faced with situations in which the meaning of a CS changes, as in the case of acquisition and later extinction, animals seem to preserve the original knowledge (CS-US) in addition to learning about the new conditions (CS-noUS). Finally, we discuss how parallels among Pavlovian conditioning, operant conditioning, and human causal judgment suggest that causal knowledge may lie at the root of both human and animal learning. All of these empirical findings and theoretical developments prove that animal learning is more complex and intricate than was once imagined. Copyright © 2009 John Wiley & Sons, Ltd. For further resources related to this article, please visit the WIREs website. Copyright © 2009 John Wiley & Sons, Ltd.

  16. Differences in Moral Judgment on Animal and Human Ethics Issues between University Students in Animal-Related, Human Medical and Arts Programs

    OpenAIRE

    Verrinder, Joy M.; Remo Ostini; Phillips, Clive J. C.

    2016-01-01

    Moral judgment in relation to animal ethics issues has rarely been investigated. Among the research that has been conducted, studies of veterinary students have shown greater use of reasoning based on universal principles for animal than human ethics issues. This study aimed to identify if this was unique to students of veterinary and other animal-related professions. The moral reasoning of first year students of veterinary medicine, veterinary technology, and production animal science was co...

  17. EPA Releases Guidance on a Voluntary Pilot Program to Reduce Animal Testing

    Science.gov (United States)

    EPA is announcing the start of a voluntary pilot program to evaluate the usefulness and acceptability of a mathematical tool that estimates the toxicological classification of a chemical, which is used in the GHS.

  18. Genomic prediction unifies animal and plant breeding programs to form platforms for biological discovery

    DEFF Research Database (Denmark)

    Hickey, John M.; Chiurugwi, Tinashe; Mackay, Ian

    2017-01-01

    The rate of annual yield increases for major staple crops must more than double relative to current levels in order to feed a predicted global population of 9 billion by 2050. Controlled hybridization and selective breeding have been used for centuries to adapt plant and animal species for human...... that unifies breeding approaches, biological discovery, and tools and methods. Here we compare and contrast some animal and plant breeding approaches to make a case for bringing the two together through the application of genomic selection. We propose a strategy for the use of genomic selection as a unifying...... use. However, achieving higher, sustainable rates of improvement in yields in various species will require renewed genetic interventions and dramatic improvement of agricultural practices. Genomic prediction of breeding values has the potential to improve selection, reduce costs and provide a platform...

  19. Genomic prediction unifies animal and plant breeding programs to form platforms for biological discovery.

    Science.gov (United States)

    Hickey, John M; Chiurugwi, Tinashe; Mackay, Ian; Powell, Wayne

    2017-08-30

    The rate of annual yield increases for major staple crops must more than double relative to current levels in order to feed a predicted global population of 9 billion by 2050. Controlled hybridization and selective breeding have been used for centuries to adapt plant and animal species for human use. However, achieving higher, sustainable rates of improvement in yields in various species will require renewed genetic interventions and dramatic improvement of agricultural practices. Genomic prediction of breeding values has the potential to improve selection, reduce costs and provide a platform that unifies breeding approaches, biological discovery, and tools and methods. Here we compare and contrast some animal and plant breeding approaches to make a case for bringing the two together through the application of genomic selection. We propose a strategy for the use of genomic selection as a unifying approach to deliver innovative 'step changes' in the rate of genetic gain at scale.

  20. 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.

  1. Animal models for small for gestational age and fetal programming of adult disease.

    Science.gov (United States)

    Vuguin, Patricia M

    2007-01-01

    Fetal growth retardation is a fetal adaptation in response to inadequate supply of oxygen and/or nutrients. Animal models of intrauterine growth retardation are an invaluable tool to question the genetic, molecular and cellular events that determine fetal growth and development. Rodent and non-litter bearing animals are mammalian system with similar embryology,anatomy and physiology to humans. Utilization of these systems has led to a greater understanding of the pathophysiology and consequences of intrauterine growth retardation. These observations are comparable to that observed in humans born small for gestational age, and are of interest because of the known association between poor fetal growth and development of adult disease. All the experimental manipulations described here have altered a number of metabolic and physiological variables, but the pattern of alterations seems to vary with the procedure and species employed. This review describes animal models for intrauterine growth retardation and assesses their potentials and limitations at aiming to improve strategies for the prevention of adult disease.

  2. Extinction Events Can Accelerate Evolution

    DEFF Research Database (Denmark)

    Lehman, Joel; Miikkulainen, Risto

    2015-01-01

    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......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...

  3. Extinction events can accelerate evolution.

    Directory of Open Access Journals (Sweden)

    Joel Lehman

    Full Text Available 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 in the long term.

  4. Extinction Events Can Accelerate Evolution

    Science.gov (United States)

    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 in the long term. PMID:26266804

  5. Field Epidemiology and Laboratory Training Programs in West Africa as a model for sustainable partnerships in animal and human health.

    Science.gov (United States)

    Becker, Karen M; Ohuabunwo, Chima; Ndjakani, Yassa; Nguku, Patrick; Nsubuga, Peter; Mukanga, David; Wurapa, Frederick

    2012-09-01

    The concept of animal and human health experts working together toward a healthier world has been endorsed, but challenges remain in identifying concrete actions to move this one health concept from vision to action. In 2008, as a result of avian influenza outbreaks in West Africa, international donor support led to a unique opportunity to invest in Field Epidemiology and Laboratory Training Programs (FELTPs) in the region that engaged the animal and human health sectors to strengthen the capacity for prevention and control of zoonotic diseases. The FELTPs mixed 25% to 35% classroom and 65% to 75% field-based training and service for cohorts of physicians, veterinarians, and laboratory scientists. They typically consisted of a 2-year course leading to a master's degree in field epidemiology and public health laboratory management for midlevel public health leaders and competency-based short courses for frontline public health surveillance workers. Trainees and graduates work in multidisciplinary teams to conduct surveillance, outbreak investigations, and epidemiological studies for disease control locally and across borders. Critical outcomes of these programs include development of a cadre of public health leaders with core skills in integrated disease surveillance, outbreak investigation, vaccination campaigns, laboratory diagnostic testing, and epidemiological studies that address priority public health problems. A key challenge exists in identifying ways to successfully scale up and transform this innovative donor-driven program into a sustainable multisectoral one health workforce capacity development model.

  6. Reducing the number of animals used for microsurgery training programs by using a task-trainer simulator.

    Science.gov (United States)

    Guerreschi, P; Qassemyar, A; Thevenet, J; Hubert, T; Fontaine, C; Duquennoy-Martinot, V

    2014-01-01

    To master the skills needed for microsurgery techniques, residents must enrol in a long and complex training program that includes manipulations on simulators, on ex vivo tissues and finally in vivo training. This final step consists of performing vascular anastomoses on murine models. We propose here a simulation program designed to decrease the number of rats used during the final in vivo training. Our study presents the materials used, the various exercises proposed and their evaluations. Two identical student groups were compared in the framework of the University Diploma of Microsurgery. Group A (seven students) followed a classic training program, all of whom achieved permeable vascular anastomoses. A total of 149 rats were needed for this group. Group B (seven students) first validated their manipulations on the task-trainer simulation program. A mean of 6 h was necessary to obtain this validation. All these students achieved the required permeable vascular anastomoses but only 77 rats were used for this group. This simulation program spared 72 rats, abiding by the Russell and Burch concept of a humane experimental technique, namely the 3R principles. This home-made, cost-efficient and easy-to-use task trainer included various exercises with increasing difficulty levels and a progressive scoring system. We believe that microsurgery training needs to include both simple and sophisticated tools in order to reduce the number of animals used to master these surgical skills.

  7. THE MEMORY SYSTEM ENGAGED DURING ACQUISITION DETERMINES THE EFFECTIVENESS OF DIFFERENT EXTINCTION PROTOCOLS

    Directory of Open Access Journals (Sweden)

    Jarid eGoodman

    2015-11-01

    Full Text Available Previous research indicates that extinction of rodent maze behavior may occur without explicit performance of the previously required response. In latent extinction, confining an animal to a previously rewarded goal location without reinforcement is typically sufficient to produce extinction of maze learning. However, previous studies have not determined whether latent extinction may be successfully employed to extinguish all types of memory acquired in the maze, or whether only specific types of memory may be vulnerable to latent extinction. The present study examined whether latent extinction may be effective across two plus-maze tasks that depend on anatomically distinct neural systems. Adult male Long-Evans rats were trained in a hippocampus-dependent place learning task (experiment 1, in which animals were trained to approach a consistent spatial location for food reward. A separate group of rats were trained in a dorsolateral striatum-dependent response learning task (experiment 2, in which animals were trained to make a consistent egocentric body-turn response for food reward. Following training, animals received response extinction or latent extinction. For response extinction, animals were given the opportunity to execute the original running approach response toward the empty food cup. For latent extinction, animals were confined to the original goal locations with the empty food cup, thus preventing them from making the original running approach response. Results indicate that, relative to no extinction, latent extinction was effective at extinguishing memory in the place learning task, but remained ineffective in the response learning task. In contrast, typical response extinction remained very effective at extinguishing memory in both place and response learning tasks. The present findings confirm that extinction of maze learning may occur with or without overt performance of the previously acquired response, but that the

  8. The Promises and Pitfalls of Retrieval-Extinction Procedures in Preventing Relapse to Drug Seeking

    OpenAIRE

    McNally, Gavan P.; Kathryn Elizabeth Hutton-Bedbrook

    2013-01-01

    Relapse to drug seeking after treatment or a period of abstinence remains a fundamental challenge for drug users. The retrieval – extinction procedure offers promise in augmenting the efficacy of exposure based treatment for drug use and for protecting against relapse to drug seeking. Preceding extinction training with a brief retrieval or reminder trial, retrieval – extinction training, has been shown to reduce reinstatement of extinguished drug seeking in animal models and also to produce p...

  9. 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

  10. Animal welfare indicators and environmental enrichment programs in species of wild mammals in captivity

    OpenAIRE

    Soriano Jiménez, Ana Isabel

    2013-01-01

    [spa] En la actualidad, los cuatro objetivos de los zoos modernos son la educación, la investigación, la conservación y el ocio. Esta tesis se centró en la evaluación de algunos indicadores de bienestar animal en cuatro especies de mamíferos en condiciones de cautividad (el patrón de actividad diario, la ocurrencia de conductas aberrantes, el uso del espacio y las interacciones sociales). Los principales resultados obtenidos en este estudio pueden resumirse en: 1) Las conductas aberrantes en ...

  11. A Survey of Successful Evaluations of Program Visualization and Algorithm Animation Systems

    Science.gov (United States)

    Urquiza-Fuentes, Jaime; Velazquez-Iturbide, J. Angel

    2009-01-01

    This article reviews successful educational experiences in using program and algorithm visualizations (PAVs). First, we survey a total of 18 PAV systems that were subject to 33 evaluations. We found that half of the systems have only been tested for usability, and those were shallow inspections. The rest were evaluated with respect to their…

  12. A Survey of Successful Evaluations of Program Visualization and Algorithm Animation Systems

    Science.gov (United States)

    Urquiza-Fuentes, Jaime; Velazquez-Iturbide, J. Angel

    2009-01-01

    This article reviews successful educational experiences in using program and algorithm visualizations (PAVs). First, we survey a total of 18 PAV systems that were subject to 33 evaluations. We found that half of the systems have only been tested for usability, and those were shallow inspections. The rest were evaluated with respect to their…

  13. 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.

  14. Fear extinction can be made state-dependent on peripheral epinephrine: role of norepinephrine in the nucleus tractus solitarius.

    Science.gov (United States)

    Rosa, Jessica; Myskiw, Jociane C; Furini, Cristiane R G; Sapiras, Gerson G; Izquierdo, Ivan

    2014-09-01

    We investigate whether the extinction of inhibitory avoidance (IA) learning can be subjected to endogenous state-dependence with systemic injections of epinephrine (E), and whether endogenous norepinephrine (NE) and the nucleus tractus solitarius (NTS)→locus coeruleus→hippocampus/amygdala (HIPP/BLA) pathway participate in this. Rats trained in IA were submitted to two sessions of extinction 24 h apart: In the first, the animals were submitted to a training session of extinction, and in the second they were tested for the retention of extinction. Saline or E were given i.p. immediately after the extinction training (post-extinction training injections) and/or 6 min before the extinction test (pre-extinction test). Post-extinction training E (50 or 100 μg/kg) induced a poor retrieval of extinction in the test session of this task unless an additional E injection (50 μg/kg) was given prior to the extinction test. This suggested state-dependence. Muscimol (0.01 μg/side) microinfused into the NTS prior to the extinction test session blocked E-induced state-dependence. Norepinephrine (NE, 1 μg/side) infused bilaterally into NTS restores the extinction impairment caused by post-extinction training i.p. E. In animals with bilateral NTS blockade induced by muscimol, NE (1 μg/side) given prior to the extinction test into the CA1 region of the dorsal hippocampus or into the basolateral amygdala restored the normal extinction levels that had been impaired by muscimol. These results suggest a role for the NTS→locus coeruleus→HIPP/BLA pathway in the retrieval of extinction, as it has been shown to have in the consolidation of inhibitory avoidance and of object recognition learning.

  15. Cannabinoid modulation of prefrontal-limbic activation during fear extinction learning and recall in humans.

    Science.gov (United States)

    Rabinak, Christine A; Angstadt, Mike; Lyons, Maryssa; Mori, Shoko; Milad, Mohammed R; Liberzon, Israel; Phan, K Luan

    2014-09-01

    Pre-extinction administration of Δ9-tetrahydrocannibinol (THC) facilitates recall of extinction in healthy humans, and evidence from animal studies suggest that this likely occurs via enhancement of the cannabinoid system within the ventromedial prefrontal cortex (vmPFC) and hippocampus (HIPP), brain structures critical to fear extinction. However, the effect of cannabinoids on the underlying neural circuitry of extinction memory recall in humans has not been demonstrated. We conducted a functional magnetic resonance imaging (fMRI) study using a randomized, double-blind, placebo-controlled, between-subjects design (N=14/group) coupled with a standard Pavlovian fear extinction paradigm and an acute pharmacological challenge with oral dronabinol (synthetic THC) in healthy adult volunteers. We examined the effects of THC on vmPFC and HIPP activation when tested for recall of extinction learning 24 h after extinction learning. Compared to subjects who received placebo, participants who received THC showed increased vmPFC and HIPP activation to a previously extinguished conditioned stimulus (CS+E) during extinction memory recall. This study provides the first evidence that pre-extinction administration of THC modulates prefrontal-limbic circuits during fear extinction in humans and prompts future investigation to test if cannabinoid agonists can rescue or correct the impaired behavioral and neural function during extinction recall in patients with PTSD. Ultimately, the cannabinoid system may serve as a promising target for innovative intervention strategies (e.g. pharmacological enhancement of exposure-based therapy) in PTSD and other fear learning-related disorders.

  16. Programmed cell death: similarities and differences in animals and plants. A flower paradigm.

    Science.gov (United States)

    Mea, M Della; Serafini-Fracassini, D; Duca, S Del

    2007-08-01

    After an overview of the criteria for the definition of cell death in the animal cell and of its different types of death, a comparative analysis of PCD in the plant cell is reported. The cytological characteristics of the plant cell undergoing PCD are described. The role of plant hormones and growth factors in the regulation of this event is discussed with particular emphasis on PCD activation or prevention by polyamine treatment (doses, timing and developmental stage of the organism) in a Developmental cell death plant model: the Nicotiana tabacum (tobacco) flower corolla. Some of the effects of polyamines might be mediated by transglutaminase catalysis. The activity of this enzyme was examined in different parts of the corolla during its life span showing an acropetal trend parallel to the cell death wave. The location of transglutaminase in some sub-cellular compartments suggests that it exerts different functions in the corolla DCD.

  17. Psychological Evaluation of Animal-assisted Intervention (AAI) Programs Involving Visiting Dogs and Cats for Alcohol Dependents: A Pilot Study.

    Science.gov (United States)

    Ohtani, Nobuyo; Narita, Shin; Yoshihara, Eiji; Ohta, Mitsuaki; Iwahashi, Kazuhiko

    2015-12-01

    The purpose of this study was to develop an evaluation method for animal-assisted intervention (AAI) programs involving Mood Check List-Short form.2 (MCL-S.2) and the State-Trait Anxiety Inventory (STAI) for psychiatric daycare of Japanese alcohol. dependents. A total of 36 alcohol dependents completed the study and questionnaires assessing their state. A single session of AAI reduced both subjective and physiological measures of state anxiety (A-State); and this program induced a significant reduction in the anxiety after an AAI program session with the dogs and cats involved in the intervention (p = 0.001). The Wilcoxon t-test showed that there were also significant differences in the "anxiety", "pleasantness", and "relaxation". scores for MCL-S.2 among the alcohol dependents, before and after AAI; a significantly decreased "anxiety" score (p = 0.006), and increased "pleasantness" (p = 0.002) and "relaxation" (p=0.012) scores for MCL-S.2 after AAI. The results of this study indicated that alcohol dependents who experienced a group AAI session-program exhibited significant improvements in their feeling; decreased anxiety, and increased pleasantness and relaxation.

  18. Does the Animal Fun program improve social-emotional and behavioural outcomes in children aged 4-6 years?

    Science.gov (United States)

    Piek, Jan P; Kane, Robert; Rigoli, Daniela; McLaren, Sue; Roberts, Clare M; Rooney, Rosanna; Jensen, Lynn; Dender, Alma; Packer, Tanya; Straker, Leon

    2015-10-01

    Animal Fun was designed to enhance motor and social development in young children. Its efficacy in improving motor skills was presented previously using a randomised controlled trial and a multivariate nested cohort design. Based on the Environmental Stress Hypothesis, it was argued that the program would also result in positive mental health outcomes, investigated in the current study. Pre-intervention scores were recorded for 511 children aged 4.83-6.17 years (M=5.42, SD=.30). Intervention and control groups were compared 6 months following intervention, and again in their first school year. Changes in teacher-rated prosocial behaviour and total difficulties were assessed using the Strengths and Difficulties Questionnaire, and data analysed using Generalised Linear Mixed Models. There was a significant improvement in prosocial behaviour of children in the intervention group six months after initial testing, which remained at 18-month follow-up. Total difficulties decreased at 6 months for the intervention group, with no change at 18 months. This effect was present only for the hyperactivity/inattention subscale. The only significant change for the control group was an increase in hyperactivity/inattention scores from pre-intervention to 18-month follow-up. The Animal Fun program appears to be effective in improving social and behavioural outcomes.

  19. Resistance to Extinction: A Measure of Orbitofrontal Function Suitable for Children?

    Science.gov (United States)

    Happaney, Keith; Zelazo, Philip David

    2004-01-01

    Extinction of operantly conditioned responses, which provides a measure of the ability to adapt to changes in the reinforcement value of stimuli, has been linked to orbitofrontal cortex (OFC) in human and non-human animals. This article examines the feasibility of using extinction as a measure of the development of OFC function in preschool-age…

  20. Differential Endocannabinoid Regulation of Extinction in Appetitive and Aversive Barnes Maze Tasks

    Science.gov (United States)

    Harloe, John P.; Thorpe, Andrew J.; Lichtman, Aron H.

    2008-01-01

    CB[subscript 1] receptor-compromised animals show profound deficits in extinguishing learned behavior from aversive conditioning tasks, but display normal extinction learning in appetitive operant tasks. However, it is difficult to discern whether the differential involvement of the endogenous cannabinoid system on extinction results from the…

  1. 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.

  2. Learning Anime Studio

    CERN Document Server

    Troftgruben, Chad

    2014-01-01

    Anime Studio is your complete animation program to help you create 2D movies, cartoons, anime, and cut out animations. You can create your own animated shorts and use Anime Studio to produce cartoon animations for film, video, or streaming over the Web, which can be enjoyed on YouTube, Vimeo, and other popular sites. Anime Studio is great for hobbyists and professionals alike, combining tools for both illustration and animation. With Anime Studio's easy-to-use interface, you will be creating an animated masterpiece in no time. This practical, step-by-step guide will provide you with a structur

  3. The end-Permian mass extinction: A complex, multicausal extinction

    Science.gov (United States)

    Erwin, D. H.

    1994-01-01

    The end-Permian mass extinction was the most extensive in the history of life and remains one of the most complex. Understanding its causes is particularly important because it anchors the putative 26-m.y. pattern of periodic extinction. However, there is no good evidence for an impact and this extinction appears to be more complex than others, involving at least three phases. The first began with the onset of a marine regression during the Late Permian and resulting elimination of most marine basins, reduction in habitat area, and increased climatic instability; the first pulse of tetrapod extinctions occurred in South Africa at this time. The second phase involved increased regression in many areas (although apparently not in South China) and heightened climatic instability and environmental degradation. Release of gas hydrates, oxidation of marine carbon, and the eruption of the Siberian flood basalts occurred during this phase. The final phase of the extinction episode began with the earliest Triassic marine regression and destruction of nearshore continental habitats. Some evidence suggests oceanic anoxia may have developed during the final phase of the extinction, although it appears to have been insufficient to the sole cause of the extinction.

  4. Paws for a Study Break: Running an Animal-Assisted Therapy Program at the Gerstein Science Information Centre

    Directory of Open Access Journals (Sweden)

    Allison Bell

    2013-06-01

    Full Text Available The Gerstein Science Information Centre is the Science and Health Sciences library serving the University of Toronto community. As the second largest library on campus, Gerstein is a mecca for studying and can accommodate 1100 students. Research has shown that high levels of stress, anxiety, depression, and other mental health disorders are prevalent among both medical students and the student population as a whole. In recent years, Gerstein staff members have seen evidence of the rising levels of student stress in their dealings with the public while providing reference and research help. Animal-assisted therapy (AAT is often used in hospital and rehabilitation settings and, most recently, to help young children learn to read by providing a stress-free learning environment in public libraries and schools. Studies on animal-assisted therapy have shown that AAT decreases blood pressure, cortisol, and reduces anxiety overall. In response to these findings, staff at Gerstein decided to implement an AAT program, “Paws for a Study Break,” comprised of several sessions when a therapy dog and her handler would visit the library to hold ‘office hours’ and give students a break from their studying during the Winter 2012 exam period. Through a total of six visits of ninety minutes each, 417 visitors were received. Best practices and lessons learned are discussed, including steps involved in coordination of the event, working with volunteers, publicity avenues, dealing with media requests, costs involved, and evaluation techniques. Based on the completed evaluation forms, the response to the therapy dog program at Gerstein was overwhelmingly positive; students were very appreciative, and there are plans underway to repeat this program on an ongoing basis.

  5. Functional Extinctions of Species in Ecological Networks

    OpenAIRE

    Säterberg, Torbjörn

    2016-01-01

    Current rates of extinctions are estimated to be around 1000 times higher than background rates that would occur without anthropogenic impacts. These extinction rates refer to the traditional view of extinctions, i.e. numerical extinctions. This thesis is about another type of extinctions: functional extinctions. Those occur when the abundance of a species is too small to uphold the species’ ecologically interactive role. I have taken a theoretical approach and used dynamical models to invest...

  6. Linking indices for biodiversity monitoring to extinction risk theory.

    Science.gov (United States)

    McCarthy, Michael A; Moore, Alana L; Krauss, Jochen; Morgan, John W; Clements, Christopher F

    2014-12-01

    Biodiversity indices often combine data from different species when used in monitoring programs. Heuristic properties can suggest preferred indices, but we lack objective ways to discriminate between indices with similar heuristics. Biodiversity indices can be evaluated by determining how well they reflect management objectives that a monitoring program aims to support. For example, the Convention on Biological Diversity requires reporting about extinction rates, so simple indices that reflect extinction risk would be valuable. We developed 3 biodiversity indices that are based on simple models of population viability that relate extinction risk to abundance. We based the first index on the geometric mean abundance of species and the second on a more general power mean. In a third index, we integrated the geometric mean abundance and trend. These indices require the same data as previous indices, but they also relate directly to extinction risk. Field data for butterflies and woodland plants and experimental studies of protozoan communities show that the indices correlate with local extinction rates. Applying the index based on the geometric mean to global data on changes in avian abundance suggested that the average extinction probability of birds has increased approximately 1% from 1970 to 2009.

  7. Individual Differences in Fear Extinction and Anxiety-Like Behavior

    Science.gov (United States)

    King, Gabrielle; Scott, Elliot; Graham, Bronwyn M.; Richardson, Rick

    2017-01-01

    There is growing appreciation for the substantial individual differences in the acquisition and inhibition of aversive associations, and the insights this might give into identifying individuals particularly vulnerable to stress and psychopathology. We examined whether animals that differed in rate of extinction (i.e., Fast versus Slow) were…

  8. Outbreak and Extinction Dynamics in a Stochastic Ebola Model

    Science.gov (United States)

    Nieddu, Garrett; Bianco, Simone; Billings, Lora; Forgoston, Eric; Kaufman, James

    A zoonotic disease is a disease that can be passed between animals and humans. In many cases zoonotic diseases can persist in the animal population even if there are no infections in the human population. In this case we call the infected animal population the reservoir for the disease. Ebola virus disease (EVD) and SARS are both notable examples of such diseases. There is little work devoted to understanding stochastic disease extinction and reintroduction in the presence of a reservoir. Here we build a stochastic model for EVD and explicitly consider the presence of an animal reservoir. Using a master equation approach and a WKB ansatz, we determine the associated Hamiltonian of the system. Hamilton's equations are then used to numerically compute the 12-dimensional optimal path to extinction, which is then used to estimate mean extinction times. We also numerically investigate the behavior of the model for dynamic population size. Our results provide an improved understanding of outbreak and extinction dynamics in diseases like EVD.

  9. The effect of morphine on fear extinction in rats.

    Science.gov (United States)

    Morris, M D; Gebhart, G F

    1978-05-31

    Rats were trained on an appetitive discretetrial discriminated-punishment task in which they learned to suppress responding when an intense flashing light predicting punishment was present and to respond rapidly on trials when the flashing light was absent. Once animals were performing discriminatively, 0.75, 3.0, or 6.0 mg/kg of morphine (base) was administered and a fear extinction session consisting of 60 nonshocked presentations of the flashing light was given. Two saline control groups, one that received fear extinction and one that did not, were also included in the experiment. On the day following fear extinction, all rats were tested in the undrugged state on the discriminated punishment problem, but without shock. The rats receiving 3.0 and 6.0 mg/kg of morphine before the fear extinction session were suppressed by the flashing light more than the saline extinction group or the 0.75 mg/kg morphine treatment group. Moreover, the two higher dose morphine groups were suppressed as readily as the saline group that received no fear extinction. These results are attributed to the antiemotionality effects of morphine.

  10. Program SPACECAP: software for estimating animal density using spatially explicit capture-recapture models

    Science.gov (United States)

    Gopalaswamy, Arjun M.; Royle, J. Andrew; Hines, James E.; Singh, Pallavi; Jathanna, Devcharan; Kumar, N. Samba; Karanth, K. Ullas

    2012-01-01

    1. The advent of spatially explicit capture-recapture models is changing the way ecologists analyse capture-recapture data. However, the advantages offered by these new models are not fully exploited because they can be difficult to implement. 2. To address this need, we developed a user-friendly software package, created within the R programming environment, called SPACECAP. This package implements Bayesian spatially explicit hierarchical models to analyse spatial capture-recapture data. 3. Given that a large number of field biologists prefer software with graphical user interfaces for analysing their data, SPACECAP is particularly useful as a tool to increase the adoption of Bayesian spatially explicit capture-recapture methods in practice.

  11. The effects of implementing a feral cat spay/neuter program in a Florida county animal control service.

    Science.gov (United States)

    Hughes, Kathy L; Slater, Margaret R; Haller, Linda

    2002-01-01

    In 1995, a county animal control service implemented a feral cat sterilization program with the goal of reducing the number of healthy cats euthanized, complaints, and the county's costs. The service collected data from a 6-year period both before and after the program's implementation. The service totaled the numbers of both cat and dog impoundments, surgeries, adoptions, euthanasias, and complaints for each year; standardized both sets of numbers on a per- 10,000-person basis to compare trends between dogs and cats; and calculated estimated costs for neutering versus impounding and euthanizing the feral cats. Changing from a policy of euthanasia of feral cats to support for trap-neuter-return did not result in an increase in the number of complaints or cat impoundments. The percentage of impounded cats euthanized decreased between the periods before and after the program began, and the percentage adopted increased. The ratio of complaints to impounds decreased between the 2 periods, and the ratio of surgeries to impounds increased. Impoundments of cats were relatively steady in spite of the continually increasing human population. Euthanasias decreased for both cats and dogs since 1997. Since 1996, complaints decreased for both. Surgeries for both cats and dogs increased over the 12 years. Adoptions for cats and dogs increased greatly in fiscal year 1998/1999.

  12. Mass Extinctions in Earth's History

    Science.gov (United States)

    Ward, P. D.

    2002-12-01

    Mass extinctions are short intervals of elevated species death. Possible causes of Earth's mass extinctions are both external (astronomical) and internal (tectonic and biotic changes from planetary mechanisms). Paleontologists have identified five "major" mass extinctions (>50 die-off in less than a million years) and more than 20 other minor events over the past 550 million years. Earlier major extinction events undoubtedly also occurred, but we have no fossil record; these were probably associated with, for example, the early heavy bombardment that cleared out the solar system, the advent of oxygen in the atmosphere, and various "snowball Earth" events. Mass extinctions are viewed as both destructive (species death ) and constructive, in that they allow evolutionary innovation in the wake of species disappearances. From an astrobiological perspective, mass extinctions must be considered as able both to reduce biodiversity and even potentially end life on any planet. Of the five major mass extinctions identified on Earth, only one (the Cretaceous/Tertiary event 65 million years ago that famously killed off the dinosaurs ) is unambiguously related to the impact of an asteroid or comet ( 10-km diameter). The Permian/Triassic (250 Myr ago) and Triassic/Jurassic (202 Myr ago) events are now the center of debate between those favoring impact and those suggesting large volume flooding by basaltic lavas. The final two events, Ordovician (440 Myr ago) and Devonian (370 Myr ago) have no accepted causal mechanisms.

  13. The learning of fear extinction.

    Science.gov (United States)

    Furini, Cristiane; Myskiw, Jociane; Izquierdo, Ivan

    2014-11-01

    Recent work on the extinction of fear-motivated learning places emphasis on its putative circuitry and on its modulation. Extinction is the learned inhibition of retrieval of previously acquired responses. Fear extinction is used as a major component of exposure therapy in the treatment of fear memories such as those of the posttraumatic stress disorder (PTSD). It is initiated and maintained by interactions between the hippocampus, basolateral amygdala and ventromedial prefrontal cortex, which involve feedback regulation of the latter by the other two areas. Fear extinction depends on NMDA receptor activation. It is positively modulated by d-serine acting on the glycine site of NMDA receptors and blocked by AP5 (2-amino-5-phosphono propionate) in the three structures. In addition, histamine acting on H2 receptors and endocannabinoids acting on CB1 receptors in the three brain areas mentioned, and muscarinic cholinergic fibers from the medial septum to hippocampal CA1 positively modulate fear extinction. Importantly, fear extinction can be made state-dependent on circulating epinephrine, which may play a role in situations of stress. Exposure to a novel experience can strongly enhance the consolidation of fear extinction through a synaptic tagging and capture mechanism; this may be useful in the therapy of states caused by fear memory like PTSD.

  14. Lessons Learned from the First Two Years of Nature's Notebook, the USA National Phenology Network's Plant and Animal Observation Program

    Science.gov (United States)

    Crimmins, T. M.; Rosemartin, A.; Denny, E. G.; Weltzin, J. F.; Marsh, L.

    2010-12-01

    Nature’s Notebook is the USA National Phenology Network’s (USA-NPN) national-scale plant and animal phenology observation program. The program was launched in March 2009 focusing only on plants; 2010 saw the addition of animals and the name and identity “Nature’s Notebook.” Over these two years, we have learned much about how to effectively recruit, train, and retain participants. We have engaged several thousand participants and can report a retention rate, reflected in the number of registered individuals that report observations, of approximately 25%. In 2009, participants reported observations on 133 species of plants on an average of nine days of the year, resulting in over 151,000 records in the USA-NPN phenology database. Results for the 2010 growing season are still being reported. Some of our most valuable lessons learned have been gleaned from communications with our observers. Through an informal survey, participants indicated that they would like to see more regular and consistent communications from USA-NPN program staff; clear, concise, and readily available training materials; mechanisms to keep them engaged and continuing to participate; and quick turn-around on data summaries. We are using this feedback to shape our program into the future. Another key observation we’ve made about our program is the value of locally and regionally-based efforts to implement Nature’s Notebook; some of our most committed observers are participating through partner programs such as the University of California-Santa Barbara Phenology Stewardship Program, Arbor Day Foundation, and the Great Sunflower Project. Future plans include reaching out to more partner organizations and improving our support for locally-based implementations of the Nature’s Notebook program. We have also recognized that the means for reaching and retaining potential participants in Nature’s Notebook vary greatly across generations. As the majority of our participants to

  15. The effects of animal-assisted therapy on wounded warriors in an Occupational Therapy Life Skills program.

    Science.gov (United States)

    Beck, Christine E; Gonzales, Florie; Sells, Carol Haertlein; Jones, Cynthia; Reer, Theresa; Zhu, Yao Yao

    2012-01-01

    Animal-assisted therapy (AAT) has gained much attention in civilian and military health care. Evidence supports its benefits with varied populations with diseases and disabilities, but no research has been done with injured or ill service members. This pretest, posttest nonrandomized control group study evaluated the effects of AAT on Warriors in transition (N=24) attending an Occupational Therapy Life Skills program with the long-term goal of improving their successful reintegration. Although significant differences were not found between the groups on most measures, anecdotal reports by participants and observers indicate that participants eagerly anticipated being with the therapy dogs, expressed pleasure and satisfaction with the experience, and regretted seeing it end. There were significant correlations between mood, stress, resilience, fatigue, and function at various measurement points. This is the first study to formally assess the benefits of AAT with wounded service members in garrison. Suggestions for future research are provided.

  16. The application of medical informatics to the veterinary management programs at companion animal practices in Alberta, Canada: a case study.

    Science.gov (United States)

    Anholt, R M; Berezowski, J; Maclean, K; Russell, M L; Jamal, I; Stephen, C

    2014-02-01

    Companion animals closely share their domestic environment with people and have the potential to, act as sources of zoonotic diseases. They also have the potential to be sentinels of infectious and noninfectious, diseases. With the exception of rabies, there has been minimal ongoing surveillance of, companion animals in Canada. We developed customized data extraction software, the University of, Calgary Data Extraction Program (UCDEP), to automatically extract and warehouse the electronic, medical records (EMR) from participating private veterinary practices to make them available for, disease surveillance and knowledge creation for evidence-based practice. It was not possible to build, generic data extraction software; the UCDEP required customization to meet the specific software, capabilities of the veterinary practices. The UCDEP, tailored to the participating veterinary practices', management software, was capable of extracting data from the EMR with greater than 99%, completeness and accuracy. The experiences of the people developing and using the UCDEP and the, quality of the extracted data were evaluated. The electronic medical record data stored in the data, warehouse may be a valuable resource for surveillance and evidence-based medical research.

  17. Evaluation of Cannabidiol in Animal Seizure Models by the Epilepsy Therapy Screening Program (ETSP).

    Science.gov (United States)

    Klein, Brian D; Jacobson, Catherine A; Metcalf, Cameron S; Smith, Misty D; Wilcox, Karen S; Hampson, Aidan J; Kehne, John H

    2017-07-01

    Cannabidiol (CBD) is a cannabinoid component of marijuana that has no significant activity at cannabinoid receptors or psychoactive effects. There is considerable interest in CBD as a therapy for epilepsy. Almost a third of epilepsy patients are not adequately controlled by clinically available anti-seizure drugs (ASDs). Initial studies appear to demonstrate that CBD preparations may be a useful treatment for pharmacoresistant epilepsy. The National Institute of Neurological Disorders and Stroke (NINDS) funded Epilepsy Therapy Screening Program (ETSP) investigated CBD in a battery of seizure models using a refocused screening protocol aimed at identifying pharmacotherapies to address the unmet need in pharmacoresistant epilepsy. Applying this new screening workflow, CBD was investigated in mouse 6 Hz 44 mA, maximal electroshock (MES), corneal kindling models and rat MES and lamotrigine-resistant amygdala kindling models. Following intraperitoneal (i.p.) pretreatment, CBD produced dose-dependent protection in the acute seizure models; mouse 6 Hz 44 mA (ED50 164 mg/kg), mouse MES (ED50 83.5 mg/kg) and rat MES (ED50 88.9 mg/kg). In chronic models, CBD produced dose-dependent protection in the corneal kindled mouse (ED50 119 mg/kg) but CBD (up to 300 mg/kg) was not protective in the lamotrigine-resistant amygdala kindled rat. Motor impairment assessed in conjunction with the acute seizure models showed that CBD exerted seizure protection at non-impairing doses. The ETSP investigation demonstrates that CBD exhibits anti-seizure properties in acute seizure models and the corneal kindled mouse. However, further preclinical and clinical studies are needed to determine the potential for CBD to address the unmet needs in pharmacoresistant epilepsy.

  18. Seeking a paleontological signature for mass extinctions caused by flood basalt eruptions

    Science.gov (United States)

    Payne, J.; Bush, A. M.; Chang, E. T.; Heim, N. A.; Knope, M. L.; Pruss, S. B.

    2016-12-01

    Flood basalt eruptions coincide with numerous extinction events in the fossil record. Increasingly precise absolute age determinations for both the timing of eruption and of species extinctions have strengthened the case for flood basalt eruptions as the single most important trigger for major mass extinction events in the fossil record. However, the extent to which flood basalt eruptions cause a pattern of biotic loss distinctive from extinctions triggered by other geological or biological processes remains an open question. In the absence of diagnostic mapping between geological triggers and biological losses, establishing the identities of causal agents for mass extinctions will continue to depend primarily on evidence for temporal coincidence. Here we use a synoptic database of marine animal genera spanning the Phanerozoic, including times of first and last occurrence, body size, motility, life position, feeding mode, and respiratory physiology to assess whether extinction events temporally associated with flood basalt eruptions exhibit a diagnostic pattern of extinction selectivity. We further ask whether any events not associated with known large igneous provinces nevertheless display extinction patterns suggestive of such a cause. Finally, we ask whether extinction events associated with other primary causes, such as glaciation or bolide impact, are distinguishable from events apparently triggered by flood basalt eruptions on the basis of extinction selectivity patterns

  19. Low-frequency stimulation of the ventral hippocampus facilitates extinction of contextual fear.

    Science.gov (United States)

    Cleren, Carine; Tallarida, Isabelle; Guiniec, Emilie Le; Janin, François; Nachon, Ophélie; Canini, Frédéric; Spennato, Guillaume; Moreau, Jean-Luc; Garcia, René

    2013-03-01

    Difficulties to treat fear-associated disorders, including posttraumatic stress disorder, are thought to result from dysfunction in fear extinction learning and/or memory. Animal studies on extinction modulation are therefore promising for the development of new treatments. Recent rat studies, including ones using low-frequency stimulation (LFS), have demonstrated that the ventral hippocampus (VH) modulates extinction memory. The present study explores whether the VH also modulates extinction learning. For this, rats were implanted with stimulating electrodes in the VH and experienced contextual fear conditioning, followed 6 or 24 h later by VH LFS and three sessions of extinction training. We found that, whatever the delay used (6 or 24 h), animals that received VH LFS displayed persistent low levels of freezing from the second extinction session, whereas control rats showed low levels of freezing only during the third session. In animals submitted to a stress condition (provoked by a single inescapable foot-shock followed by three sessions of situational reminders) prior to fear conditioning, VH LFS also reduced freezing levels, which, in contrast, remained high in control rats during the course of extinction training. These data suggest that LFS, targeting the VH, may be useful in reducing fear responses during extinction learning.

  20. The effects of compound stimulus extinction and inhibition of noradrenaline reuptake on the renewal of alcohol seeking

    Science.gov (United States)

    Furlong, T M; Pan, M J; Corbit, L H

    2015-01-01

    Alcohol-related stimuli can trigger relapse of alcohol-seeking behaviors even after extended periods of abstinence. Extinction of such stimuli can reduce their impact on relapse; however, the expression of extinction can be disrupted when testing occurs outside the context where extinction learning took place, an effect termed renewal. Behavioral and pharmacological methods have recently been shown to augment extinction learning; yet, it is not known whether the improved expression of extinction following these treatments remains context-dependent. Here we examined whether two methods, compound–stimulus extinction and treatment with the noradrenaline reuptake inhibitor atomoxetine, would reduce the vulnerability of extinction to a change in context. Following alcohol self-administration, responding was extinguished in a distinct context. After initial extinction, further extinction was given to a target stimulus presented in compound with another alcohol-predictive stimulus intended to augment prediction error (Experiment 1) or after a systemic injection of atomoxetine (1.0 mg kg−1; Experiment 2). A stimulus extinguished as part of a compound elicited less responding than a stimulus receiving equal extinction alone regardless of whether animals were tested in the training or extinction context; however, reliable renewal was not observed in this paradigm. Importantly, atomoxetine enhanced extinction relative to controls even in the presence of a reliable renewal effect. Thus, extinction of alcohol-seeking behavior can be improved by extinguishing multiple alcohol-predictive stimuli or enhancing noradrenaline neurotransmission during extinction training. Importantly, both methods improve extinction even when the context is changed between extinction training and test, and thus could be utilized to enhance the outcome of extinction-based treatments for alcohol-use disorders. PMID:26327688

  1. The promises and pitfalls of retrieval-extinction procedures in preventing relapse to drug seeking

    Directory of Open Access Journals (Sweden)

    Gavan P McNally

    2013-03-01

    Full Text Available Relapse to drug seeking after treatment or a period of abstinence remains a fundamental challenge for drug users. The retrieval – extinction procedure offers promise in augmenting the efficacy of exposure based treatment for drug use and for protecting against relapse to drug seeking. Preceding extinction training with a brief retrieval or reminder trial, retrieval – extinction training, has been shown to reduce reinstatement of extinguished drug seeking in animal models and also to produce profound and long lasting decrements in cue-induced craving in human heroin users. However, the mechanisms that mediate these effects of retrieval - extinction training are unclear. Moreover, under some circumstances, the retrieval – extinction procedure can significantly increase vulnerability to reinstatement in animal models.

  2. The Evolution of Multicellular Plants and Animals.

    Science.gov (United States)

    Valentine, James W.

    1978-01-01

    Traces the evolution of unicellular organisms to the multi-cellular plants and animals in existence today. Major events are depicted in a geologic timetable. Organisms, extinct and recent, are classified by taxonomic group. (MA)

  3. The Formation and Extinction of Fear Memory in Tree Shrews

    Directory of Open Access Journals (Sweden)

    Shujiang eShang

    2015-07-01

    Full Text Available Fear is an emotion that is well studied due to its importance for animal survival. Experimental animals, such as rats and mice, have been widely used to model fear. However, higher animals such as nonhuman primates have rarely been used to study fear due to ethical issues and high costs. Tree shrews are small mammals that are closely related to primates; they have been used to model human-related psychosocial conditions such as stress and alcohol tolerance. Here, we describe an experimental paradigm to study the formation and extinction of fear memory in tree shrews. We designed an experimental apparatus of a light/dark box with a voltage foot shock. We found that tree shrews preferred staying in the dark box in the daytime without stimulation and showed avoidance to voltage shocks applied to the footplate in a voltage-dependent manner. Foot shocks applied to the dark box for 5 days (10 minutes per day effectively reversed the light–dark preference of the tree shrews, and this memory lasted for more than 50 days without any sign of memory decay (extinction in the absence of further stimulation. However, this fear memory was reversed with 4 days of reverse training by applying the same stimulus to the light box. When reducing the stimulus intensity during the training period, a memory extinction and subsequently reinstatement effects were observed. Thus, our results describe an efficient method of monitoring fear memory formation and extinction in tree shrews.

  4. The formation and extinction of fear memory in tree shrews.

    Science.gov (United States)

    Shang, Shujiang; Wang, Cong; Guo, Chengbing; Huang, Xu; Wang, Liecheng; Zhang, Chen

    2015-01-01

    Fear is an emotion that is well-studied due to its importance for animal survival. Experimental animals, such as rats and mice, have been widely used to model fear. However, higher animals such as nonhuman primates have rarely been used to study fear due to ethical issues and high costs. Tree shrews are small mammals that are closely related to primates; they have been used to model human-related psychosocial conditions such as stress and alcohol tolerance. Here, we describe an experimental paradigm to study the formation and extinction of fear memory in tree shrews. We designed an experimental apparatus of a light/dark box with a voltage foot shock. We found that tree shrews preferred staying in the dark box in the daytime without stimulation and showed avoidance to voltage shocks applied to the footplate in a voltage-dependent manner. Foot shocks applied to the dark box for 5 days (10 min per day) effectively reversed the light-dark preference of the tree shrews, and this memory lasted for more than 50 days without any sign of memory decay (extinction) in the absence of further stimulation. However, this fear memory was reversed with 4 days of reverse training by applying the same stimulus to the light box. When reducing the stimulus intensity during the training period, a memory extinction and subsequently reinstatement effects were observed. Thus, our results describe an efficient method of monitoring fear memory formation and extinction in tree shrews.

  5. Extinction, relapse, and behavioral momentum.

    Science.gov (United States)

    Podlesnik, Christopher A; Shahan, Timothy A

    2010-05-01

    Previous experiments on behavioral momentum have shown that relative resistance to extinction of operant behavior in the presence of a discriminative stimulus depends upon the baseline rate or magnitude of reinforcement associated with that stimulus (i.e., the Pavlovian stimulus-reinforcer relation). Recently, we have shown that relapse of operant behavior in reinstatement, resurgence, and context renewal preparations also is a function of baseline stimulus-reinforcer relations. In this paper we present new data examining the role of baseline stimulus-reinforcer relations on resistance to extinction and relapse using a variety of baseline training conditions and relapse operations. Furthermore, we evaluate the adequacy of a behavioral momentum based model in accounting for the results. The model suggests that relapse occurs as a result of a decrease in the disruptive impact of extinction precipitated by a change in circumstances associated with extinction, and that the degree of relapse is a function of the pre-extinction baseline Pavlovian stimulus-reinforcer relation. Across experiments, relative resistance to extinction and relapse were greater in the presence of stimuli associated with more favorable conditions of reinforcement and were positively related to one another. In addition, the model did a good job in accounting for these effects. Thus, behavioral momentum theory may provide a useful quantitative approach for characterizing how differential reinforcement conditions contribute to relapse of operant behavior.

  6. Thermal Transgressions and Phanerozoic Extinctions

    Science.gov (United States)

    Worsley, T. R.; Kidder, D. L.

    2007-12-01

    A number of significant Phanerozoic extinctions are associated with marine transgressions that were probably driven by rapid ocean warming. The conditions associated with what we call thermal transgressions are extremely stressful to life on Earth. The Earth system setting associated with end-Permian extinction exemplifies an end-member case of our model. The conditions favoring extreme warmth and sea-level increases driven by thermal expansion are also conducive to changes in ocean circulation that foster widespread anoxia and sulfidic subsurface ocean waters. Equable climates are characterized by reduced wind shear and weak surface ocean circulation. Late Permian and Early Triassic thermohaline circulation differs considerably from today's world, with minimal polar sinking and intensified mid-latitude sinking that delivers sulfate from shallow evaporative areas to deeper water where it is reduced to sulfide. Reduced nutrient input to oceans from land at many of the extinction intervals results from diminished silicate weathering and weakened delivery of iron via eolian dust. The falloff in iron-bearing dust leads to minimal nitrate production, weakening food webs and rendering faunas and floras more susceptible to extinction when stressed. Factors such as heat, anoxia, ocean acidification, hypercapnia, and hydrogen sulfide poisoning would significantly affect these biotas. Intervals of tectonic quiescence set up preconditions favoring extinctions. Reductions in chemical silicate weathering lead to carbon dioxide buildup, oxygen drawdown, nutrient depletion, wind and ocean current abatement, long-term global warming, and ocean acidification. The effects of extinction triggers such as large igneous provinces, bolide impacts, and episodes of sudden methane release are more potent against the backdrop of our proposed preconditions. Extinctions that have characteristics we call for in the thermal transgressions include the Early Cambrian Sinsk event, as well as

  7. Rescue of Impaired Fear Extinction and Normalization of Cortico-Amygdala Circuit Dysfunction in a Genetic Mouse Model by Dietary Zinc Restriction

    OpenAIRE

    Whittle, Nigel; Hauschild, Markus; Lubec, Gert; Holmes, Andrew; Singewald, Nicolas

    2010-01-01

    Fear extinction is impaired in neuropsychiatric disorders, including posttraumatic stress disorder. Identifying drugs that facilitate fear extinction in animal models provides leads for novel pharmacological treatments for these disorders. Zinc (Zn) is expressed in neurons in a cortico-amygdala circuit mediating fear extinction, and modulates neurotransmitter systems regulating extinction. We previously found that the 129S1/SvImJ mouse strain (S1) exhibited a profound impairment in fear extin...

  8. Association of Animal and Plant Proteins Intake with Hypertension in Iranian Adult Population: Isfahan Healthy Heart Program

    Directory of Open Access Journals (Sweden)

    Sanaz Mehrabani

    2017-01-01

    Full Text Available Background: There is evidence regarding the relationship between dietary proteins intake and blood pressure (BP, but they had inconsistent results. Therefore, this study was designed to assess the association between different kinds of protein intake (animal and plant protein and BP. Materials and Methods: Data were collected from Isfahan Healthy Heart Program. We performed a cross-sectional study among 9660 randomly selected Iranian adults aged ≥19-year-old that they were selected from three large Iranian regions in 2007. A simplified validated 48-item-food frequency questionnaire was used to assess dietary intake including all kinds of protein. Systolic and diastolic BPs were measured in duplicate by trained personnel using a standard protocol. Multivariable regressions were applied to assess the relationship between protein intake and BP levels and the presence of hypertension (HTN. Results: More frequent consumption of animal, plant, and total protein intake were inversely associated with BP in a crude model (P < 0.001; however, after adjustment for potential confounders this relationship remained only for plant protein (P = 0.04. The risk of HTN occurrence decreased in the highest quintile of total and plant protein consumption by 19% (odds ratio [OR] = 0.81; confidence interval [CI]: [0.65–0.96]; P for trend = 0.004 and 18% (OR = 0.82; [CI: (0.67–0.94]; P for trend = 0.03, respectively. Conclusions: More frequent protein intake, especially plant protein consumption was inversely associated with BP and risk of HTN among Iranian adults.

  9. Animal Investigation Program 1976 annual report: Nevada test site and vicinity. [Radioanalysis of tissues from animals residing on or near NTS in 1976

    Energy Technology Data Exchange (ETDEWEB)

    Smith, D.D.; Giles, K.R.; Bernhardt, D.E.; Brown, K.W.

    1978-11-01

    Data are presented from the radioanalysis of tissues collected from cattle and mule deer, desert bighorn sheep, feral horses, and other wildlife that resided on or near the Nevada Test Site during 1976. Other than the naturally occurring potassium-40, gamma-emitting radionuclides were detected infrequently with the exception of /sup 131/I in animal thyroid samples collected after September 25 (the date of a Chinese nuclear test). Strontium-90 concentrations in bones from deer, cattle, and desert bighorn sheep continued the downward trend of recent years. Tritium concentrations were generally within ambient limits with the exception of animals exposed to sources of contamination; e.g., Sedan Crater, drainage ponds from Area 12 tunnels, etc. Analysis of actinide in tissues was emphasized during 1976. Graphs illustrate the /sup 239/P levels in lungs, livers, and femurs from Nevada Test Site beef cattle for the years 1971 through 1976. Femur and lung residue data are nearly identical for each year with liver concentrations being a factor of 2 or 3 lower. Hypothetical dose estimates to man were calculated on the basis of the daily consumption of 0.5 kilogram of liver or muscle from animals that contained peak actinide levels. The highest postulated dose was 11 millirem from tritium from tissues for a mule deer. This dose is about 2% of the 500 millirems/year guide for radiation doses to an individual in the general public. All other postulated doses for consumption of the tissue containing other radionuclides are less than 0.1% of this guide. The food habits of desert bighorn sheep were discussed according to the geographic locations of the animals at time of collection. Grasses made up approximately 60% of the diet at all locations, with shrubs content approaching 30%, and the remainder consisting of various forbs. The movement of 13 mule deer fitted with collars containing a radiotransmitter unit was monitored on a weekly basis.

  10. The butterflies of Barro Colorado Island: Local extinction rates since the 1930's

    Science.gov (United States)

    Few data are available about the regional or local extinction of tropical butterfly species. When confirmed, local extinction was often due to the loss of host-plant species. We used published lists and recent monitoring programs to evaluate changes in butterfly composition on Barro Colorado Island ...

  11. Calcium isotope constraints on the end-Permian mass extinction.

    Science.gov (United States)

    Payne, Jonathan L; Turchyn, Alexandra V; Paytan, Adina; Depaolo, Donald J; Lehrmann, Daniel J; Yu, Meiyi; Wei, Jiayong

    2010-05-11

    The end-Permian mass extinction horizon is marked by an abrupt shift in style of carbonate sedimentation and a negative excursion in the carbon isotope (delta(13)C) composition of carbonate minerals. Several extinction scenarios consistent with these observations have been put forward. Secular variation in the calcium isotope (delta(44/40)Ca) composition of marine sediments provides a tool for distinguishing among these possibilities and thereby constraining the causes of mass extinction. Here we report delta(44/40)Ca across the Permian-Triassic boundary from marine limestone in south China. The delta(44/40)Ca exhibits a transient negative excursion of approximately 0.3 per thousand over a few hundred thousand years or less, which we interpret to reflect a change in the global delta(44/40)Ca composition of seawater. CO(2)-driven ocean acidification best explains the coincidence of the delta(44/40)Ca excursion with negative excursions in the delta(13)C of carbonates and organic matter and the preferential extinction of heavily calcified marine animals. Calcium isotope constraints on carbon cycle calculations suggest that the average delta(13)C of CO(2) released was heavier than -28 per thousand and more likely near -15 per thousand; these values indicate a source containing substantial amounts of mantle- or carbonate-derived carbon. Collectively, the results point toward Siberian Trap volcanism as the trigger of mass extinction.

  12. Colloquium paper: extinction as the loss of evolutionary history.

    Science.gov (United States)

    Erwin, Douglas H

    2008-08-12

    Current plant and animal diversity preserves at most 1-2% of the species that have existed over the past 600 million years. But understanding the evolutionary impact of these extinctions requires a variety of metrics. The traditional measurement is loss of taxa (species or a higher category) but in the absence of phylogenetic information it is difficult to distinguish the evolutionary depth of different patterns of extinction: the same species loss can encompass very different losses of evolutionary history. Furthermore, both taxic and phylogenetic measures are poor metrics of morphologic disparity. Other measures of lost diversity include: functional diversity, architectural components, behavioral and social repertoires, and developmental strategies. The canonical five mass extinctions of the Phanerozoic reveals the loss of different, albeit sometimes overlapping, aspects of loss of evolutionary history. The end-Permian mass extinction (252 Ma) reduced all measures of diversity. The same was not true of other episodes, differences that may reflect their duration and structure. The construction of biodiversity reflects similarly uneven contributions to each of these metrics. Unraveling these contributions requires greater attention to feedbacks on biodiversity and the temporal variability in their contribution to evolutionary history. Taxic diversity increases after mass extinctions, but the response by other aspects of evolutionary history is less well studied. Earlier views of postextinction biotic recovery as the refilling of empty ecospace fail to capture the dynamics of this diversity increase.

  13. Extinction of drug cue reactivity in methamphetamine-dependent individuals.

    Science.gov (United States)

    Price, Kimber L; Saladin, Michael E; Baker, Nathaniel L; Tolliver, Bryan K; DeSantis, Stacia M; McRae-Clark, Aimee L; Brady, Kathleen T

    2010-09-01

    Conditioned responses to drug-related environmental cues (such as craving) play a critical role in relapse to drug use. Animal models demonstrate that repeated exposure to drug-associated cues in the absence of drug administration leads to the extinction of conditioned responses, but the few existing clinical trials focused on extinction of conditioned responses to drug-related cues in drug-dependent individuals show equivocal results. The current study examined drug-related cue reactivity and response extinction in a laboratory setting in methamphetamine-dependent individuals. Methamphetamine cue-elicited craving was extinguished during two sessions of repeated (3) within-session exposures to multi-modal (picture, video, and in-vivo) cues, with no evidence of spontaneous recovery between sessions. A trend was noted for a greater attenuation of response in participants with longer (4-7 day) inter-session intervals. These results indicate that extinction of drug cue conditioned responding occurs in methamphetamine-dependent individuals, offering promise for the development of extinction- based treatment strategies. 2010 Elsevier Ltd. All rights reserved.

  14. Effects of endocannabinoid and endovanilloid systems on aversive memory extinction.

    Science.gov (United States)

    Laricchiuta, Daniela; Centonze, Diego; Petrosini, Laura

    2013-11-01

    In contextual fear conditioning animals have to integrate various elemental stimuli into a coherent representation of the condition and then associate context representation with punishment. Although several studies indicated the modulating role of endocannabinoid system (ECS) on the associative learning, ECS effect on contextual fear conditioning requires further investigations. The present study assessed the effects of the increased endocannabinoid anandamide (AEA) tone on acquisition, retrieval and extinction of the contextual fear conditioning. Given that AEA may bind to cannabinoid type 1 (CB1) receptors as well as to postsynaptic ionotropic Transient Receptor Potential Vanilloid type 1 (TRPV1) channels, particular attention was paid in determining how the increased AEA tone influenced fear responses. Furthermore, it was investigated how the ECS modulated the effects of stress-sensitization on fear response. Thus, mice submitted or not to a social defeat stress protocol were treated with drugs acting on ECS, CB1 receptors or TRPV1 channels and tested in a contextual fear conditioning whose conditioning, retrieval and extinction phases were analyzed. ECS activation influenced the extinction process and contrasted the stress effects on fear memory. Furthermore, CB1 receptor antagonist blocked and TRPV1 channel antagonist promoted short- and long-term extinction. The present study indicates that ECS controls the extinction of aversive memories in the contextual fear conditioning.

  15. Extinction of Drug Cue Reactivity in Methamphetamine-Dependent Individuals

    Science.gov (United States)

    Price, Kimber L.; Saladin, Michael E.; Baker, Nathaniel L.; Tolliver, Bryan K.; DeSantis, Stacia M.; McRae-Clark, Aimee L.; Brady, Kathleen T.

    2010-01-01

    Conditioned responses to drug-related environmental cues (such as craving) play a critical role in relapse to drug use. Animal models demonstrate that repeated exposure to drug-associated cues in the absence of drug administration leads to the extinction of conditioned responses, but the few existing clinical trials focused on extinction of conditioned responses to drug-related cues in drug-dependent individuals show equivocal results. The current study examined drug-related cue reactivity and response extinction in a laboratory setting in methamphetamine-dependent individuals. Methamphetamine cue-elicited craving was extinguished during two sessions of repeated (3) within-session exposures to multi-modal (picture, video, and in-vivo) cues, with no evidence of spontaneous recovery between sessions. A trend was noted for a greater attenuation of response in participants with longer (4-7 day) inter-session intervals. These results indicate that extinction of drug-cue conditioned responding occurs in methamphetamine-dependent individuals, offering promise for the development of extinction- based treatment strategies. PMID:20538262

  16. Mass extinctions show selective patterns in crinoid body size

    Science.gov (United States)

    Soto, A.; Tang, C.; Pelagio, M.; Heim, N. A.; Payne, J.

    2013-12-01

    There have been five major extinctions on planet Earth: the end of the Ordovician, late Devonian, late Permian, late Triassic and the late Cretaceous and through all of these, Crinoids have still managed to prosper. Our project attempts to find a correlation between these five mass extinctions and the body size of Crinoids. Past research has shown that bigger animals are more prone to extinction compared to smaller sized ones because of their complex environmental niches. We hypothesized that small-sized Crinoids would have a higher possibility of survival compared to the larger-sized Crinoids. We first graphed Crinoids' maximum body size and the five major extinctions throughout time for any visual correlation between them. We then used t-tests as our statistical analyses to find any differences between the size of survivors and. There was no mean difference between the mean size of victims and survivors with the exception of the end of the Triassic extinction. There are many possible explanations for this difference in the end of the Triassic such as 1) a rise in atmospheric CO2, 2) a combination was volcanic CO2 and catastrophic dissociation of gas hydrate, and/or 3) a cooling in temperature and oceanic changes occurred.

  17. Quantification of habitat fragmentation reveals extinction risk in terrestrial mammals.

    Science.gov (United States)

    Crooks, Kevin R; Burdett, Christopher L; Theobald, David M; King, Sarah R B; Di Marco, Moreno; Rondinini, Carlo; Boitani, Luigi

    2017-07-18

    Although habitat fragmentation is often assumed to be a primary driver of extinction, global patterns of fragmentation and its relationship to extinction risk have not been consistently quantified for any major animal taxon. We developed high-resolution habitat fragmentation models and used phylogenetic comparative methods to quantify the effects of habitat fragmentation on the world's terrestrial mammals, including 4,018 species across 26 taxonomic Orders. Results demonstrate that species with more fragmentation are at greater risk of extinction, even after accounting for the effects of key macroecological predictors, such as body size and geographic range size. Species with higher fragmentation had smaller ranges and a lower proportion of high-suitability habitat within their range, and most high-suitability habitat occurred outside of protected areas, further elevating extinction risk. Our models provide a quantitative evaluation of extinction risk assessments for species, allow for identification of emerging threats in species not classified as threatened, and provide maps of global hotspots of fragmentation for the world's terrestrial mammals. Quantification of habitat fragmentation will help guide threat assessment and strategic priorities for global mammal conservation.

  18. Estimates of the magnitudes of major marine mass extinctions in earth history

    Science.gov (United States)

    Stanley, Steven M.

    2016-10-01

    Procedures introduced here make it possible, first, to show that background (piecemeal) extinction is recorded throughout geologic stages and substages (not all extinction has occurred suddenly at the ends of such intervals); second, to separate out background extinction from mass extinction for a major crisis in earth history; and third, to correct for clustering of extinctions when using the rarefaction method to estimate the percentage of species lost in a mass extinction. Also presented here is a method for estimating the magnitude of the Signor-Lipps effect, which is the incorrect assignment of extinctions that occurred during a crisis to an interval preceding the crisis because of the incompleteness of the fossil record. Estimates for the magnitudes of mass extinctions presented here are in most cases lower than those previously published. They indicate that only ˜81% of marine species died out in the great terminal Permian crisis, whereas levels of 90-96% have frequently been quoted in the literature. Calculations of the latter numbers were incorrectly based on combined data for the Middle and Late Permian mass extinctions. About 90 orders and more than 220 families of marine animals survived the terminal Permian crisis, and they embodied an enormous amount of morphological, physiological, and ecological diversity. Life did not nearly disappear at the end of the Permian, as has often been claimed.

  19. Estimates of the magnitudes of major marine mass extinctions in earth history.

    Science.gov (United States)

    Stanley, Steven M

    2016-10-18

    Procedures introduced here make it possible, first, to show that background (piecemeal) extinction is recorded throughout geologic stages and substages (not all extinction has occurred suddenly at the ends of such intervals); second, to separate out background extinction from mass extinction for a major crisis in earth history; and third, to correct for clustering of extinctions when using the rarefaction method to estimate the percentage of species lost in a mass extinction. Also presented here is a method for estimating the magnitude of the Signor-Lipps effect, which is the incorrect assignment of extinctions that occurred during a crisis to an interval preceding the crisis because of the incompleteness of the fossil record. Estimates for the magnitudes of mass extinctions presented here are in most cases lower than those previously published. They indicate that only ∼81% of marine species died out in the great terminal Permian crisis, whereas levels of 90-96% have frequently been quoted in the literature. Calculations of the latter numbers were incorrectly based on combined data for the Middle and Late Permian mass extinctions. About 90 orders and more than 220 families of marine animals survived the terminal Permian crisis, and they embodied an enormous amount of morphological, physiological, and ecological diversity. Life did not nearly disappear at the end of the Permian, as has often been claimed.

  20. 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.

  1. Measuring Galactic Extinction A Test

    CERN Document Server

    Arce, H G; Arce, Hector G.; Goodman, Alyssa A.

    1999-01-01

    We test the recently published all-sky reddening map of Schlegel, Finkbeiner & Davis (1998 [SFD]) using the extinction study of a region in the Taurus dark cloud complex by Arce & Goodman (1999 [AG]). In their study, AG use four different techniques to measure the amount and structure of the extinction toward Taurus, and all four techniques agree very well. Thus we believe that the AG results are a truthful representation of the extinction in the region and can be used to test the reliability of the SFD reddening map. The results of our test show that the SFD all-sky reddening map, which is based on data from COBE/DIRBE and IRAS/ISSA, overestimates the reddening by a factor of 1.3 to 1.5 in regions of smooth extinction with A_V > 0.5 mag. In some regions of steep extinction gradients the SFD map underestimates the reddening value, probably due to its low spatial resolution. We expect that the astronomical community will be using the SFD reddening map extensively. We offer this Letter as a cautionary n...

  2. Physics for Animation Artists

    Science.gov (United States)

    Chai, David; Garcia, Alejandro L.

    2011-01-01

    Animation has become enormously popular in feature films, television, and video games. Art departments and film schools at universities as well as animation programs at high schools have expanded in recent years to meet the growing demands for animation artists. Professional animators identify the technological facet as the most rapidly advancing…

  3. Social buffering enhances extinction of conditioned fear responses in male rats.

    Science.gov (United States)

    Mikami, Kaori; Kiyokawa, Yasushi; Takeuchi, Yukari; Mori, Yuji

    2016-09-01

    In social species, the phenomenon in which the presence of conspecific animals mitigates stress responses is called social buffering. We previously reported that social buffering in male rats ameliorated behavioral fear responses, as well as hypothalamic-pituitary-adrenal axis activation, elicited by an auditory conditioned stimulus (CS). However, after social buffering, it is not clear whether rats exhibit fear responses when they are re-exposed to the same CS in the absence of another rat. In the present study, we addressed this issue using an experimental model of extinction. High stress levels during extinction training impaired extinction, suggesting that extinction is enhanced when stress levels during extinction training are low. Therefore, we hypothesized that rats that had received social buffering during extinction training would not show fear responses to a CS, even in the absence of another rat, because social buffering had enhanced the extinction of conditioned fear responses. To test this, we subjected male fear-conditioned rats to extinction training either alone or with a non-conditioned male rat. The subjects were then individually re-exposed to the CS in a recall test. When the subjects individually underwent extinction training, no responses were suppressed in the recall test. Conversely, when the subjects received social buffering during extinction training, freezing and Fos expression in the paraventricular nucleus of the hypothalamus and lateral amygdala were suppressed. Additionally, the effects of social buffering were absent when the recall test was conducted in a different context from the extinction training. The present results suggest that social buffering enhances extinction of conditioned fear responses.

  4. The fossil record of evolution: Data on diversification and extinction

    Science.gov (United States)

    Sepkoski, J. J., Jr.

    1991-01-01

    Understanding of the evolution of complex life, and of the roles that changing terrestrial and extraterrestrial environments played in life's history, is dependent upon synthetic knowledge of the fossil record. Paleontologists have been describing fossils for more that two centuries. However, much of this information is dispersed in monographs and journal articles published throughout the world. Over the past several years, this literature was surveyed, and a data base on times of origination and extinction of fossil genera was compiled. The data base, which now holds approximately 32,000 genera, covers all taxonomic groups of marine animals, incorporates the most recent taxonomic assignments, and uses a detailed global time framework that can resolve originations and extinctions to intervals averaging three million years in duration. These data can be used to compile patterns of global biodiversity, measure rates of taxic evolution, and test hypotheses concerning adaptive radiations, mass extinctions, etc. Thus far, considerable effort was devoted to using the data to test the hypothesis of periodicity of mass extinction. Rates of extinction measured from the data base have also been used to calibrate models of evolutionary radiations in marine environments. It was observed that new groups, or clades of animals (i.e., orders and classes) tend to reach appreciable diversity first in nearshore environments and then to radiate in more offshore environments; during decline, these clades may disappear from the nearshore while persisting in offshore, deep water habitats. These observations have led to suggestions that there is something special about stressful or perturbed environments that promotes the evolution of novel kinds of animals that can rapidly replace their predecessors. The numerical model that is being investigated to study this phenomenon treats environments along onshore-offshore gradients as if they were discrete habitats. Other aspects of this

  5. The atmospheric extinction of light

    CERN Document Server

    Hughes, Stephen W; Powell, Sean; Carroll, Joshua

    2015-01-01

    An experiment is described that enables students to understand the properties of atmospheric extinction due to Rayleigh scattering. The experiment requires the use of red, green and blue lasers attached to a travelling microscope or similar device. The laser beams are passed through an artificial atmosphere, made from milky water, at varying depths, before impinging on either a light meter or a photodiode integral to a Picotech Dr. DAQ ADC. A plot of measured spectral intensity verses depth reveals the contribution Rayleigh scattering has to the extinction coefficient. For the experiment with the light meter, the extinction coefficients for red, green and blue light in the milky sample of water were 0.27, 0.36 and 0.47 cm^-1 respectively and 0.032, 0.037 and 0.092 cm^-1 for the Picotech Dr. DAQ ADC.

  6. Mass extinctions and supernova explosions

    CERN Document Server

    Korschinek, Gunther

    2016-01-01

    A nearby supernova (SN) explosion could have negatively influenced life on Earth, maybe even been responsible for mass extinctions. Mass extinction poses a significant extinction of numerous species on Earth, as recorded in the paleontologic, paleoclimatic, and geological record of our planet. Depending on the distance between the Sun and the SN, different types of threats have to be considered, such as ozone depletion on Earth, causing increased exposure to the Sun's ultraviolet radiation, or the direct exposure of lethal x-rays. Another indirect effect is cloud formation, induced by cosmic rays in the atmosphere which result in a drop in the Earth's temperature, causing major glaciations of the Earth. The discovery of highly intensive gamma ray bursts (GRBs), which could be connected to SNe, initiated further discussions on possible life-threatening events in Earth's history. The probability that GRBs hit the Earth is very low. Nevertheless, a past interaction of Earth with GRBs and/or SNe cannot be exclude...

  7. Extinction debt on oceanic islands

    DEFF Research Database (Denmark)

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

    2010-01-01

    Habitat destruction is the leading cause of species extinctions. However, there is typically a time-lag between the reduction in habitat area and the eventual disappearance of the remnant populations. These "surviving but ultimately doomed" species represent an extinction debt. Calculating...... 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...... in the last 45 yr, despite the extensive sampling effort, offer support to the predictions made. We argue that immediate action to restore and expand native forest habitat is required to avert the loss of numerous endemic species in the near future...

  8. Habituation, latent inhibition, and extinction.

    Science.gov (United States)

    Jordan, Wesley P; Todd, Travis P; Bucci, David J; Leaton, Robert N

    2015-06-01

    In two conditioned suppression experiments with a latent inhibition (LI) design, we measured the habituation of rats in preexposure, their LI during conditioning, and then extinction over days. In the first experiment, lick suppression, the preexposed group (PE) showed a significant initial unconditioned response (UR) to the target stimulus and significant long-term habituation (LTH) of that response over days. The significant difference between the PE and nonpreexposed (NPE) groups on the first conditioning trial was due solely to the difference in their URs to the conditioned stimulus (CS)-a habituated response (PE) and an unhabituated response (NPE). In the second experiment, bar-press suppression, little UR to the target stimulus was apparent during preexposure, and no detectable LTH. Thus, there was no difference between the PE and NPE groups on the first conditioning trial. Whether the UR to the CS confounds the interpretation of LI (Exp. 1) or not (Exp. 2) can only be known if the UR is measured. In both experiments, LI was observed in acquisition. Also in both experiments, rats that were preexposed and then conditioned to asymptote were significantly more resistant to extinction than were the rats not preexposed. This result contrasts with the consistently reported finding that preexposure either produces less resistance to extinction or has no effect on extinction. The effect of stimulus preexposure survived conditioning to asymptote and was reflected directly in extinction. These two experiments provide a cautionary procedural note for LI experiments and have shown an unexpected extinction effect that may provide new insights into the interpretation of LI.

  9. Extinction risk of soil biota.

    Science.gov (United States)

    Veresoglou, Stavros D; Halley, John M; Rillig, Matthias C

    2015-11-23

    No species lives on earth forever. Knowing when and why species go extinct is crucial for a complete understanding of the consequences of anthropogenic activity, and its impact on ecosystem functioning. Even though soil biota play a key role in maintaining the functioning of ecosystems, the vast majority of existing studies focus on aboveground organisms. Many questions about the fate of belowground organisms remain open, so the combined effort of theorists and applied ecologists is needed in the ongoing development of soil extinction ecology.

  10. Interstellar Grains: Effect of Inclusions on Extinction

    CERN Document Server

    Katyal, Nisha; Vaidya, D B

    2011-01-01

    A composite dust grain model which simultaneously explains the observed interstellar extinction, polarization, IR emission and the abundance constraints, is required. We present a composite grain model, which is made up of a host silicate oblate spheroid and graphite inclusions. The interstellar extinction curve is evaluated in the spectral region 3.4-0.1$\\mu m$ using the extinction efficiencies of the composite spheroidal grains for three axial ratios. Extinction curves are computed using the discrete dipole approximation (DDA). The model curves are subsequently compared with the average observed interstellar extinction curve and with an extinction curve derived from the IUE catalogue data.

  11. Interstellar grains: Effect of inclusions on extinction

    Science.gov (United States)

    Katyal, N.; Gupta, R.; Vaidya, D. B.

    2011-10-01

    A composite dust grain model which simultaneously explains the observed interstellar extinction, polarization, IR emission and the abundance constraints, is required. We present a composite grain model, which is made up of a host silicate oblate spheroid and graphite inclusions. The interstellar extinction curve is evaluated in the spectral region 3.4-0.1 μm using the extinction efficiencies of composite spheroidal grains for three axial ratios. Extinction curves are computed using the discrete dipole approximation (DDA). The model curves are subsequently compared with the average observed interstellar extinction curve and with an extinction curve derived from the IUE catalogue data.

  12. An Educational MONTE CARLO Simulation/Animation Program for the Cosmic Rays Muons and a Prototype Computer-Driven Hardware Display.

    Science.gov (United States)

    Kalkanis, G.; Sarris, M. M.

    1999-01-01

    Describes an educational software program for the study of and detection methods for the cosmic ray muons passing through several light transparent materials (i.e., water, air, etc.). Simulates muons and Cherenkov photons' paths and interactions and visualizes/animates them on the computer screen using Monte Carlo methods/techniques which employ…

  13. An examination of nucleus accumbens cell firing during extinction and reinstatement of water reinforcement behavior in rats.

    Science.gov (United States)

    Hollander, Jonathan A; Ijames, Stephanie G; Roop, Richard G; Carelli, Regina M

    2002-03-08

    Electrophysiological recording procedures were used to examine nucleus accumbens (Acb) cell firing in rats (n = 13) during water reinforcement sessions consisting of three phases. During phase one (maintenance), a lever press resulted in water reinforcement (fixed ratio 1; 0.05 ml/press) paired with an auditory stimulus (0.5 s). Of 128 Acb neurons recorded during maintenance, 40 cells (31%) exhibited one of three types of neuronal firing patterns described previously [J. Neurosci. 14 (12) (1994) 7735-7746; J. Neurosci. 20 (11) (2000) 4255-4266]. Briefly, Acb neurons exhibited increases in firing rate within seconds preceding the reinforced response (type PR) or increases (type RFe) or decreases (type RFi) in activity seconds following response completion. In phase two (extinction), subsequent lever pressing had no programmed consequences (i.e., water reinforcement and the auditory stimulus were not presented). After 30 min of no responding, animals were given water reinforcement/auditory stimulus 'primes' to reestablish lever pressing behavior during the third phase (reinstatement). Results indicated that all types of phasic neurons (PR, RFe and RFi) exhibited an attenuated firing rate during extinction, and in some cases recovery of patterned discharges were observed during reinstatement. No significant changes in cell firing were observed for any cell type during presentation of the stimulus prime used to reestablish operant responding following extinction. These findings are discussed in terms of how Acb neurons process information related to 'natural' reinforcers versus drugs of abuse.

  14. Endangered and Extinct Radioactivity

    Science.gov (United States)

    Leising, M. D.

    1993-07-01

    Gamma ray spectroscopy holds great promise for probing nucleosynthesis in individual nucleosynthesis events, via observations of short-lived radioactivity, and for measuring global galactic nucleosynthesis today with detections of longer-lived radioactivity. Many of the astrophysical issues addressed by these observations are precisely those that must be understood in order to interpret observations of extinct radioactivity in meteorites. It was somewhat surprising that the former case was realized first for a Type II supernova, when both 56Co [1] and 57Co [2] were detected in SN 1987A. These provide unprecedented constraints on models of Type II explosions. Live 26Al in the galaxy might come from Type II supernovae and their progenitors, and if this is eventually shown to be the case, can constrain massive star evolution, supernova nucleosynthesis, the galactic Type II supernova rate, and even models of the chemical evolution of the galaxy [3]. Titanium-44 is produced primarily in the alpha-rich freezeout from nuclear statistical equilibrium, possibly in Type Ia [4] and almost certainly in Type II supernovae [5]. The galactic recurrence time of these events is comparable to the 44Ti lifetime, so we expect to be able to see at most a few otherwise unseen 44Ti remnants at any given time. No such remnants have been detected yet [6]. Very simple arguments lead to the expectation that about 4 x 10^-4 M(sub)solar mass of 44Ca are produced per century. The product of the supernova frequency times the 44Ti yield per event must equal this number. Even assuming that only the latest event would be seen, rates in excess of 2 century^-1 are ruled out at >=99% confidence by the gamma ray limits. Only rates less than 0.3 century^-1 are acceptable at >5% confidence, and this means that the yield per event must be >10^-3 M(sub)solar mass to produce the requisite 44Ca. Rates this low are incompatible with current estimates for Type II supernovae and yields this high are also very

  15. Mid-Infrared Extinction and its Variation with Galactic Longitude

    CERN Document Server

    Gao, Jian; Li, A

    2009-01-01

    Based on the data obtained from the Spitzer/GLIPMSE Legacy Program and the 2MASS project, we derive the extinction in the four IRAC bands, [3.6], [4.5], [5.8] and [8.0] micron, relative to the 2MASS Ks band (at 2.16 micron) for 131 GLIPMSE fields along the Galactic plane within |l|<65 deg, using red giants and red clump giants as tracers. As a whole, the mean extinction in the IRAC bands (normalized to the 2MASS Ks band), A_[3.6]/A_Ks=0.63, A_[4.5]/A_Ks=0.57, A_[5.8]/A_Ks=0.49, A_[8.0]/A_Ks=0.55, exhibits little variation with wavelength (i.e. the extinction is somewhat flat or gray). This is consistent with previous studies and agrees with that predicted from the standard interstellar grain model for R_V=5.5 by Weingartner & Draine (2001). As far as individual sightline is concerned, however, the wavelength dependence of the mid-infrared interstellar extinction A_{lambda}/A_Ks varies from one sightline to another, suggesting that there may not exist a "universal" IR extinction law. We, for the first t...

  16. A model of mass extinction

    CERN Document Server

    Newman, M E J

    1997-01-01

    A number of authors have in recent years proposed that the processes of macroevolution may give rise to self-organized critical phenomena which could have a significant effect on the dynamics of ecosystems. In particular it has been suggested that mass extinction may arise through a purely biotic mechanism as the result of so-called coevolutionary avalanches. In this paper we first explore the empirical evidence which has been put forward in favor of this conclusion. The data center principally around the existence of power-law functional forms in the distribution of the sizes of extinction events and other quantities. We then propose a new mathematical model of mass extinction which does not rely on coevolutionary effects and in which extinction is caused entirely by the action of environmental stresses on species. In combination with a simple model of species adaptation we show that this process can account for all the observed data without the need to invoke coevolution and critical processes. The model al...

  17. Extinction debt on oceanic islands

    DEFF Research Database (Denmark)

    Triantis, K.A.; Borges, Paulo A. V.; Ladle, R.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...

  18. Aggregation Bifurcation, and Extinction in Exploited Animal Population.

    Science.gov (United States)

    1978-03-01

    59) becomes0 2 = - - cxx . - (59a) Equation (59a) is the “constant-yield” equation studied by Brauer • and Soudack. I 1 7a...F. Brauer and A.C. Soudack (1978), “Stability Regions and Transition Phenomena for Harvested Predator Prey Systems ,” Preprint. 2. C.W. Clark and M...Un,rooity. Albaisy. N.Y.) AD A 005 617 Berplso.far, Fred G., “Salaria,—A Framework for tIle Study of Trend,” 8 pp., D.c 1973, (Pubhshod PP 121 pp 133

  19. The influence of partner cues on the extinction of causal judgments in people.

    Science.gov (United States)

    Holmes, Nathan M; Griffiths, Oren; Westbrook, R Frederick

    2014-09-01

    Studies in laboratory animals have shown that the extinction of a conditioned stimulus, A, is regulated by the associative history of a second stimulus, X, when the two are extinguished in simultaneous compound: An inhibitory X protects A from extinction (Rescorla Learning & Behavior, 31, 124-132, 2003), whereas an excitatory X facilitates, and under some circumstances deepens, the extinction of A (Rescorla Journal of Experimental Psychology: Animal Behavior Processes, 26, 251-260, 2000, Journal of Experimental Psychology: Animal Behavior Processes, 32, 135-144, 2006). In the present study, we used the allergist task to examine whether the extinction of causal judgments in people is similarly regulated by the causal status of co-present stimuli. Experiment 1 showed that a cue trained as a conditioned inhibitor protected a target cue from extinction: The target extinguished in compound with the inhibitor was rated as being more causal of the outcome than was a target extinguished in compound with a control cue lacking inhibitory properties. In contrast, the remaining experiments showed that the extinction of a target cue was regulated by the presence, but not the causal status, of a partner cue: Target cues extinguished in compound were protected from extinction, and no evidence showed that an already extinguished partner conferred more protection (Exp. 2), or that an excitatory partner conferred any less protection (Exps. 2 and 3), or that an excitatory partner deepened the extinction of its already extinguished target. These findings are inconsistent with elemental models that rely on a common error term to explain associative changes in extinction. They are largely, but not completely, consistent with the configural model proposed by Pearce (Psychological Review, 94, 61-73, 1987), which predicts an ordering of levels of protection that was not observed.

  20. Interstellar Extinction by Spheroidal Dust Grains

    OpenAIRE

    Gupta, Ranjan; Mukai, Tadashi; Vaidya, D. B.; Sen, Asoke K.; Okada, Yasuhiko

    2005-01-01

    Observations of interstellar extinction and polarization indicate that the interstellar medium consists of aligned non-spherical dust grains which show variation in the interstellar extinction curve for wavelengths ranging from NIR to UV. To model the extinction and polarization, one cannot use the Mie theory which assumes the grains as solid spheres. We have used a T-matrix based method for computing the extinction efficiencies of spheroidal silicate and graphite grains of different shapes (...

  1. From the neurobiology of extinction to improved clinical treatments.

    Science.gov (United States)

    Morrison, Filomene G; Ressler, Kerry J

    2014-04-01

    The neural circuitry underlying the fear response is extremely well conserved across mammalian species, which has allowed for the rapid translation of research findings in rodent models of fear to therapeutic interventions in human populations. Many aspects of exposure-based psychotherapy treatments in humans, which are widely used in the treatment of PTSD, panic disorder, phobias, and other anxiety disorders, are closely paralleled by extinction training in rodent fear conditioning models. Here, we discuss how the neural circuitry of fear learning and extinction in rodent animal models may be used to understand the underlying neural circuitry of fear-related disorders, such as PTSD in humans. We examine the factors that contribute to the pathology and development of PTSD. Next, we will review how fear is measured in animal models using classical Pavlovian fear conditioning paradigms, as well as brain regions such as the amygdala, which are involved in the fear response across species. Finally, we highlight the following three systems involved in the extinction of fear, all of which represent promising avenues for therapeutic interventions in the clinic: (1) the role of the glutamatergic N-methyl-d-aspartate (NMDA) receptor, (2) the role of the brain-derived neurotrophic factor (BDNF)-tyrosine kinase B (TrkB) induced signaling pathway, and (3) the role of the renin-angiotensin system. The modulation of pathways underlying fear learning and extinction, such as the ones presented in this review, in combination with extinction-based exposure therapy, represents promising avenues for therapeutic intervention in the treatment of human fear related disorders.

  2. 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.

  3. 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)…

  4. Determining Extinction Ratio Of A Laser Diode

    Science.gov (United States)

    Unger, Glenn L.

    1992-01-01

    Improved technique to determine extinction ratio of pulsed laser diode based partly on definition of extinction ratio applicable to nonideal laser pulses. Heretofore, determinations involved assumption of ideal laser pulses, and neglected optical power from background light. Because power fluctuates during real pulse, more realistic to define extinction ratio in terms of energy obtained.

  5. 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.

  6. Colloquium paper: species invasions and extinction: the future of native biodiversity on islands.

    Science.gov (United States)

    Sax, Dov F; Gaines, Steven D

    2008-08-12

    Predation by exotic species has caused the extinction of many native animal species on islands, whereas competition from exotic plants has caused few native plant extinctions. Exotic plant addition to islands is highly nonrandom, with an almost perfect 1 to 1 match between the number of naturalized and native plant species on oceanic islands. Here, we evaluate several alternative implications of these findings. Does the consistency of increase in plant richness across islands imply that a saturation point in species richness has been reached? If not, should we expect total plant richness to continue to increase as new species are added? Finally, is the rarity of native plant extinctions to date a misleading measure of the impact of past invasions, one that hides an extinction debt that will be paid in the future? By analyzing historical records, we show that the number of naturalized plant species has increased linearly over time on many individual islands. Further, the mean ratio of naturalized to native plant species across islands has changed steadily for nearly two centuries. These patterns suggest that many more species will become naturalized on islands in the future. We also discuss how dynamics of invasion bear upon alternative saturation scenarios and the implications these scenarios have for the future retention or extinction of native plant species. Finally, we identify invasion-motivated research gaps (propagule pressure, time-lags to extinction, abundance shifts, and loss of area) that can aid in forecasting extinction and in developing a more comprehensive theory of species extinctions.

  7. Involvement of dopamine D1/D5 and D2 receptors in context-dependent extinction learning and memory reinstatement

    Directory of Open Access Journals (Sweden)

    Marion Agnes Emma Andre

    2016-01-01

    Full Text Available Dopamine contributes to the regulation of higher order information processing and executive control. It is important for memory consolidation processes, and for the adaptation of learned responses based on experience. In line with this, under aversive learning conditions, application of dopamine receptor antagonists prior to extinction result in enhanced memory reinstatement. Here, we investigated the contribution of the dopaminergic system to extinction and memory reinstatement (renewal of an appetitive spatial learning task in rodents. Rats were trained for 3 days in a T-maze (context ‘A’ to associate a goal arm with a food reward, despite low reward probability (acquisition phase. On day 4, extinction learning (unrewarded occurred, that was reinforced by a context change (‘B’. On day 5, re-exposure to the (unrewarded ‘A’-context took place (renewal of context ‘A’, followed by extinction of context ‘A’. In control animals, significant extinction occurred on day 4, that was followed by an initial memory reinstatement (renewal on day 5, that was, in turn, succeeded by extinction of renewal. Intracerebral treatment with a D1/D5-receptor antagonist prior to the extinction trials, elicited a potent enhancement of extinction in context ‘B’. By contrast, a D1/D5-agonist impaired renewal in context ’A’. Extinction in the ‘A’ context on day 5 was unaffected by the D1/D5-ligands. Treatment with a D2-receptor antagonist prior to extinction had no overall effect on extinction in context ‘B or renewal in context ‘A’, although extinction of the renewal effect was impaired on day 5, compared to controls.Taken together, these data suggest that dopamine acting on the D1/D5-receptor modulates both acquisition and consolidation of context-dependent extinction. By contrast, the D2-receptor may contribute to context-independent aspects of this kind of extinction learning.

  8. Involvement of Dopamine D1/D5 and D2 Receptors in Context-Dependent Extinction Learning and Memory Reinstatement

    Science.gov (United States)

    André, Marion Agnès Emma; Manahan-Vaughan, Denise

    2016-01-01

    Dopamine contributes to the regulation of higher order information processing and executive control. It is important for memory consolidation processes, and for the adaptation of learned responses based on experience. In line with this, under aversive learning conditions, application of dopamine receptor antagonists prior to extinction result in enhanced memory reinstatement. Here, we investigated the contribution of the dopaminergic system to extinction and memory reinstatement (renewal) of an appetitive spatial learning task in rodents. Rats were trained for 3 days in a T-maze (context “A”) to associate a goal arm with a food reward, despite low reward probability (acquisition phase). On day 4, extinction learning (unrewarded) occurred, that was reinforced by a context change (“B”). On day 5, re-exposure to the (unrewarded) “A” context took place (renewal of context “A”, followed by extinction of context “A”). In control animals, significant extinction occurred on day 4, that was followed by an initial memory reinstatement (renewal) on day 5, that was, in turn, succeeded by extinction of renewal. Intracerebral treatment with a D1/D5-receptor antagonist prior to the extinction trials, elicited a potent enhancement of extinction in context “B”. By contrast, a D1/D5-agonist impaired renewal in context “A”. Extinction in the “A” context on day 5 was unaffected by the D1/D5-ligands. Treatment with a D2-receptor antagonist prior to extinction had no overall effect on extinction in context “B” or renewal in context “A”, although extinction of the renewal effect was impaired on day 5, compared to controls. Taken together, these data suggest that dopamine acting on the D1/D5-receptor modulates both acquisition and consolidation of context-dependent extinction. By contrast, the D2-receptor may contribute to context-independent aspects of this kind of extinction learning. PMID:26834599

  9. Medial orbitofrontal cortex lesion prevents facilitatory effects of d-cycloserine during fear extinction.

    Science.gov (United States)

    Sierra, Rodrigo O; Nítola, Laura P; Duran, Johanna M; Prieto, Daysi R; León, Laura A; Cardenas, Fernando P

    2016-01-01

    Animal models of fear extinction have an important clinical relevance to pharmacological and exposure-based therapies for anxiety disorders. Lesions of prefrontal structures impair fear extinction. On the other hand, d-cycloserine is able to enhance this process. We hypothesize that the integrity of cortical structures involved in inhibitory control of emotional responses is crucial for the facilitatory effects of d-cycloserine. Here, we showed that medial orbitofrontal cortex lesion prevents d-cycloserine enhancement of fear extinction. These preliminary results suggest that effects of pharmacological treatments could be dependent on cortical activity state to promote fear memory reduction.

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

    OpenAIRE

    Brackney Ryan J; Cheung Timothy HC; Herbst Katrina; Hill Jade C; Sanabria Federico

    2012-01-01

    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 pre...

  11. A comparative analysis of specialization and extinction risk in temperate-zone bats.

    OpenAIRE

    2004-01-01

    Identifying the factors that influence the extinction risk of animals is essential in conservation biology because they help identify endangered species and provide the basis for their preservation.We present a comparative study that uses data from the literature on the diet and morphological specialization of European and North American bat species to investigate the effect of specialization on extinction risk. We focused on bats because many species are endangered and their high ecologic...

  12. Animal Investigation Program (AIP), A.I.P. summary report on and around the Nevada Test Site from 1982--1995

    Energy Technology Data Exchange (ETDEWEB)

    Giles, K.R.

    1997-04-01

    This report describes the Animal Investigation Program conducted from 1982--1995 by the Environmental Protection Agency`s (EPA`s), Radiation and Indoor Environments National Laboratory (R and IE), formerly Radiation Sciences Laboratory-Las Vegas. This laboratory operates an environmental radiation monitoring program in the region surrounding the Nevada Test Site. The surveillance program was designed to measure levels and trends of radionuclides in animals on and around the Nevada Test Site to ascertain whether world-wide fallout, current radiation levels, and associated doses, to the general public were in compliance with existing radiation protection standards. The surveillance program additionally had the responsibility to take action to protect the health and well-being of the public in the event of any accidental release of radioactive contaminants. Comparison of the measurements and sample analysis results indicated that no significant amounts of biological radionuclides had been detected in the near offsite areas or on the NTS, except in animals drinking water that drains from tunnels in Area 12.

  13. Development of Extinction Imagers for the Determination of Atmospheric Optical Extinction

    Science.gov (United States)

    2014-08-01

    extinction coefficient > 0.4 km" ), the transmissometer tends to report higher values than the MSI. There are two possible reasons for this behavior ...REPORT TYPE Final Report 4. TITLE AND SUBTITLE Development of Extinction Imagers for the Determination of Atmospheric Optical Extinction 6. AUTHOR...further develop Extinction Imagers for use in the ocean environment, and to extend the capabilities into the Short Wave IR (SWIR). Extinction Imaging

  14. Extinction learning, reconsolidation and the internal reinforcement hypothesis.

    Science.gov (United States)

    Eisenhardt, Dorothea; Menzel, Randolf

    2007-02-01

    Retrieving a consolidated memory--by exposing an animal to the learned stimulus but not to the associated reinforcement--leads to two opposing processes: one that weakens the old memory as a result of extinction learning, and another that strengthens the old, already-consolidated memory as a result of some less well-understood form of learning. This latter process of memory strengthening is often referred to as "reconsolidation", since protein synthesis can inhibit this form of memory formation. Although the behavioral phenomena of the two antagonizing forms of learning are well documented, the mechanisms behind the corresponding processes of memory formation are still quite controversial. Referring to results of extinction/reconsolidation experiments in honeybees, we argue that two opposing learning processes--with their respective consolidation phases and memories--are initiated by retrieval trials: extinction learning and reminder learning, the latter leading to the phenomenon of spontaneous recovery from extinction, a process that can be blocked with protein synthesis inhibition.

  15. Reintroduction of locally extinct vertebrates impacts arid soil fungal communities.

    Science.gov (United States)

    Clarke, Laurence J; Weyrich, Laura S; Cooper, Alan

    2015-06-01

    Introduced species have contributed to extinction of native vertebrates in many parts of the world. Changes to vertebrate assemblages are also likely to alter microbial communities through coextinction of some taxa and the introduction of others. Many attempts to restore degraded habitats involve removal of exotic vertebrates (livestock and feral animals) and reintroduction of locally extinct species, but the impact of such reintroductions on microbial communities is largely unknown. We used high-throughput DNA sequencing of the fungal internal transcribed spacer I (ITS1) region to examine whether replacing exotic vertebrates with reintroduced native vertebrates led to changes in soil fungal communities at a reserve in arid central Australia. Soil fungal diversity was significantly different between dune and swale (interdune) habitats. Fungal communities also differed significantly between sites with exotic or reintroduced native vertebrates after controlling for the effect of habitat. Several fungal operational taxonomic units (OTUs) found exclusively inside the reserve were present in scats from reintroduced native vertebrates, providing a direct link between the vertebrate assemblage and soil microbial communities. Our results show that changes to vertebrate assemblages through local extinctions and the invasion of exotic species can alter soil fungal communities. If local extinction of one or several species results in the coextinction of microbial taxa, the full complement of ecological interactions may never be restored.

  16. Protecting Animals: The New American Reality.

    Science.gov (United States)

    Mouras, Belton P.

    1984-01-01

    If animal extinction continues to accelerate at the rate that prevailed from the beginning of the century, then virtually all wildlife will be gone within 30 years. The great crusades of the past and current campaigns to save animal lives are discussed. (RM)

  17. 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.

  18. Neanderthal extinction by competitive exclusion.

    Directory of Open Access Journals (Sweden)

    William E Banks

    Full Text Available BACKGROUND: Despite a long history of investigation, considerable debate revolves around whether Neanderthals became extinct because of climate change or competition with anatomically modern humans (AMH. METHODOLOGY/PRINCIPAL FINDINGS: We apply a new methodology integrating archaeological and chronological data with high-resolution paleoclimatic simulations to define eco-cultural niches associated with Neanderthal and AMH adaptive systems during alternating cold and mild phases of Marine Isotope Stage 3. Our results indicate that Neanderthals and AMH exploited similar niches, and may have continued to do so in the absence of contact. CONCLUSIONS/SIGNIFICANCE: The southerly contraction of Neanderthal range in southwestern Europe during Greenland Interstadial 8 was not due to climate change or a change in adaptation, but rather concurrent AMH geographic expansion appears to have produced competition that led to Neanderthal extinction.

  19. Exploring co-extinction correlates

    DEFF Research Database (Denmark)

    Carpaneto, Giuseppe Maria; Mazziotta, Adriano; Pittino, Riccardo

    2011-01-01

    Co-extinction is a recurring topic in conservation biology. Quantification of co-extinction has been generally restricted to parasite-host, predator-prey and herbivore-host plant interactions. The loss of detritivorous insects upon the depletion of herbivore mammals has been poorly explored. Here...... of scarab beetle communities. Rarefaction curves estimated that a 50% reduction in the number of sample units where squirrel faecal pellets are the only available food resource accounts for a reduction of 28% of all the scarab species, and of 24% of the squirrel-linked species. The current decline of ground...... that the conservation of ground squirrels and their affiliate scarab species may be ensured by a moderate livestock grazing, owing to the higher ecological success of these rodents in the presence of large herbivores keeping low the grass cover. © 2011 Springer Science+Business Media B.V....

  20. Microworlds, Games, Animations, Mobile Apps, Puzzle Editors and More: What Is Important for an Introductory Programming Environment?

    Science.gov (United States)

    Xinogalos, Stelios; Satratzemi, Maya; Malliarakis, Christos

    2017-01-01

    Teaching and learning programming constitutes a challenge. Although several teaching approaches and programming tools have been proposed, it seems that they have limited impact on classroom practice. This article investigates students' perceptions on five educational programming environments that are widely used and the features that any…

  1. Microworlds, Games, Animations, Mobile Apps, Puzzle Editors and More: What Is Important for an Introductory Programming Environment?

    Science.gov (United States)

    Xinogalos, Stelios; Satratzemi, Maya; Malliarakis, Christos

    2017-01-01

    Teaching and learning programming constitutes a challenge. Although several teaching approaches and programming tools have been proposed, it seems that they have limited impact on classroom practice. This article investigates students' perceptions on five educational programming environments that are widely used and the features that any…

  2. Session 6: Infant nutrition: future research developments in Europe EARNEST, the early nutrition programming project: EARly Nutrition programming - long-term Efficacy and Safety Trials and integrated epidemiological, genetic, animal, consumer and economic research.

    Science.gov (United States)

    Fewtrell, M S

    2007-08-01

    Increasing evidence from lifetime experimental studies in animals and observational and experimental studies in human subjects suggests that pre- and postnatal nutrition programme long-term health. However, key unanswered questions remain on the extent of early-life programming in contemporary European populations, relevant nutritional exposures, critical time periods, mechanisms and the effectiveness of interventions to prevent or reverse programming effects. The EARly Nutrition programming - long-term Efficacy and Safety Trials and integrated epidemiological, genetic, animal, consumer and economic research (EARNEST) consortium brings together a multi-disciplinary team of scientists from European research institutions in an integrated programme of work that includes experimental studies in human subjects, modern prospective observational studies and mechanistic animal work including physiological studies, cell-culture models and molecular techniques. Theme 1 tests early nutritional programming of disease in human subjects, measuring disease markers in childhood and early adulthood in nineteen randomised controlled trials of nutritional interventions in pregnancy and infancy. Theme 2 examines associations between early nutrition and later outcomes in large modern European population-based prospective studies, with detailed measures of diet in pregnancy and early life. Theme 3 uses animal, cellular and molecular techniques to study lifetime effects of early nutrition. Biomedical studies are complemented by studies of the social and economic importance of programming (themes 4 and 5), and themes encouraging integration, communication, training and wealth creation. The project aims to: help formulate policies on the composition and testing of infant foods; improve the nutritional value of infant formulas; identify interventions to prevent and reverse adverse early nutritional programming. In addition, it has the potential to develop new products through industrial

  3. Animal assisted therapy (AAT program as a useful adjunct to conventional psychosocial rehabilitation for patients with schizophrenia: results of a small-scale randomized controlled trial.

    Directory of Open Access Journals (Sweden)

    Paula eCalvo

    2016-05-01

    Full Text Available Currently, one of the main objectives of human-animal interaction research is to demonstrate the benefits of animal-assisted therapy (AAT for specific profiles of patients or participants.The aim of this study is to assess the effect of an AAT program as an adjunct to a conventional 6-month psychosocial rehabilitation program for people with schizophrenia. Our hypothesis is that the inclusion of AAT into psychosocial rehabilitation would contribute positively to the impact of the overall program on symptomology and quality of life, and that AAT would be a positive experience for patients. To test these hypotheses, we compared pre-program with post-program scores for the Positive and Negative Syndrome Scale (PANSS and the EuroQoL-5 dimensions questionnaire (EuroQol-5D, pre-session with post-session salivary cortisol and alpha-amylase for the last four AAT sessions, and adherence rates between different elements of the program.We conducted a randomized, controlled study in a psychiatric care center in Spain. Twenty-two institutionalized patients with chronic schizophrenia completed the 6-month rehabilitation program, which included individual psychotherapy, group therapy, a functional program (intended to improve daily functioning, a community program (intended to facilitate community reintegration and a family program. Each member of the control group (n=8 participated in one activity from a range of therapeutic activities that were part of the functional program. In place of this functional program activity, the AAT-treatment group (n=14 participated in twice-weekly 1-hour sessions of AAT. All participants received the same weekly total number of hours of rehabilitation. At the end of the program, both groups (control and AAT-treatment showed significant improvements in positive and overall symptomatology, as measured with PANSS, but only the AAT-treatment group showed a significant improvement in negative symptomatology. Adherence to the AAT

  4. Animal Assisted Therapy (AAT) Program As a Useful Adjunct to Conventional Psychosocial Rehabilitation for Patients with Schizophrenia: Results of a Small-scale Randomized Controlled Trial.

    Science.gov (United States)

    Calvo, Paula; Fortuny, Joan R; Guzmán, Sergio; Macías, Cristina; Bowen, Jonathan; García, María L; Orejas, Olivia; Molins, Ferran; Tvarijonaviciute, Asta; Cerón, José J; Bulbena, Antoni; Fatjó, Jaume

    2016-01-01

    Currently, one of the main objectives of human-animal interaction research is to demonstrate the benefits of animal assisted therapy (AAT) for specific profiles of patients or participants. The aim of this study is to assess the effect of an AAT program as an adjunct to a conventional 6-month psychosocial rehabilitation program for people with schizophrenia. Our hypothesis is that the inclusion of AAT into psychosocial rehabilitation would contribute positively to the impact of the overall program on symptomology and quality of life, and that AAT would be a positive experience for patients. To test these hypotheses, we compared pre-program with post-program scores for the Positive and Negative Syndrome Scale (PANSS) and the EuroQoL-5 dimensions questionnaire (EuroQol-5D), pre-session with post-session salivary cortisol and alpha-amylase for the last four AAT sessions, and adherence rates between different elements of the program. We conducted a randomized, controlled study in a psychiatric care center in Spain. Twenty-two institutionalized patients with chronic schizophrenia completed the 6-month rehabilitation program, which included individual psychotherapy, group therapy, a functional program (intended to improve daily functioning), a community program (intended to facilitate community reintegration) and a family program. Each member of the control group (n = 8) participated in one activity from a range of therapeutic activities that were part of the functional program. In place of this functional program activity, the AAT-treatment group (n = 14) participated in twice-weekly 1-h sessions of AAT. All participants received the same weekly total number of hours of rehabilitation. At the end of the program, both groups (control and AAT-treatment) showed significant improvements in positive and overall symptomatology, as measured with PANSS, but only the AAT-treatment group showed a significant improvement in negative symptomatology. Adherence to the AAT

  5. Animal Assisted Therapy (AAT) Program As a Useful Adjunct to Conventional Psychosocial Rehabilitation for Patients with Schizophrenia: Results of a Small-scale Randomized Controlled Trial

    Science.gov (United States)

    Calvo, Paula; Fortuny, Joan R.; Guzmán, Sergio; Macías, Cristina; Bowen, Jonathan; García, María L.; Orejas, Olivia; Molins, Ferran; Tvarijonaviciute, Asta; Cerón, José J.; Bulbena, Antoni; Fatjó, Jaume

    2016-01-01

    Currently, one of the main objectives of human–animal interaction research is to demonstrate the benefits of animal assisted therapy (AAT) for specific profiles of patients or participants. The aim of this study is to assess the effect of an AAT program as an adjunct to a conventional 6–month psychosocial rehabilitation program for people with schizophrenia. Our hypothesis is that the inclusion of AAT into psychosocial rehabilitation would contribute positively to the impact of the overall program on symptomology and quality of life, and that AAT would be a positive experience for patients. To test these hypotheses, we compared pre–program with post–program scores for the Positive and Negative Syndrome Scale (PANSS) and the EuroQoL-5 dimensions questionnaire (EuroQol-5D), pre–session with post–session salivary cortisol and alpha–amylase for the last four AAT sessions, and adherence rates between different elements of the program. We conducted a randomized, controlled study in a psychiatric care center in Spain. Twenty–two institutionalized patients with chronic schizophrenia completed the 6–month rehabilitation program, which included individual psychotherapy, group therapy, a functional program (intended to improve daily functioning), a community program (intended to facilitate community reintegration) and a family program. Each member of the control group (n = 8) participated in one activity from a range of therapeutic activities that were part of the functional program. In place of this functional program activity, the AAT–treatment group (n = 14) participated in twice–weekly 1–h sessions of AAT. All participants received the same weekly total number of hours of rehabilitation. At the end of the program, both groups (control and AAT–treatment) showed significant improvements in positive and overall symptomatology, as measured with PANSS, but only the AAT–treatment group showed a significant improvement in negative symptomatology

  6. Animation program used to encourage patients or family members to take an active role for eliminating wrong-site, wrong-person, wrong-procedure surgeries: preliminary evaluation.

    Science.gov (United States)

    See, Lai-Chu; Chang, Yi-Hua; Chuang, Kai-Lan; Lai, Hui-Ru; Peng, Pei-I; Jean, Wen-Chyi; Wang, Chao-Hui

    2011-01-01

    Wrong-site surgeries (including wrong-site, wrong-person and wrong-procedure errors) remain the number one problem among adverse events of health care delivery. Patients and/or family members should be involved when possible to help prevent such errors. 1) Design an educational animation program about patient safety for patients and/or family members to help eliminate wrong-site surgery errors. 2) Evaluate its educational effect. The animation developed for this study includes an introduction, hypothetical story, and guided information, and was presented at a tertiary medical center in northern Taiwan. A single-group pretest and posttest design was used. Forty-six patients and 48 family members participated in the study. The pre-training score was 3.6 (on a scale of 1-4). After watching the animation, there was no significant increase (0.08 ± 0.5) for the patient group, but the family member group showed significant improvement (0.21 ± 0.6, P = .0309). Most participants (98.9%) were satisfied with the animation. The majority of participants reported good practices for avoiding wrong-site surgery mistakes before an operation. A significant improvement of post-training scores in the family member group was seen. The high satisfaction rating given by the participants after seeing the animation indicates that it was generally acceptable. Copyright © 2010 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.

  7. Late Pleistocene Megafaunal Extinction Consistent With YDB Impact Hypothesis at Younger Dryas Onset

    Science.gov (United States)

    Kennett, J. P.; Kennett, D. J.

    2008-12-01

    At least 35 mammal and 19 bird genera became extinct across North America near the end of the Pleistocene. Modern increases in stratigraphic and dating resolution suggest that this extinction occurred relatively rapidly near 12.9 ka (11 radiocarbon kyrs). Within the context of a long-standing debate about its cause, Firestone et al., (2007) proposed that this extinction resulted from an extraterrestrial (ET) impact over North America at 12.9 ka. This hypothesis predicts that the extinction of most of these animals should have occurred abruptly at 12.9 ka. To test this hypothesis, we have critically examined radiocarbon ages and the extinction stratigraphy of these taxa. From a large data pool, we selected only radiocarbon dates with low error margins with a preference for directly dated biological materials (e.g., bone, dung, etc.) and modern chemical purification techniques. A relatively small number of acceptable dates indicate that at least 16 animal genera and several other species became extinct close to 12.9 ka. These taxa include the most common animals of the late Pleistocene such as horses, camels, and mammoths. Also, the remains of extinct taxa are reportedly found up to, but not above, the base of a widely distributed carbon-rich layer called the black mat. This stratum forms an abrupt, major biostratigraphic boundary at the Younger Dryas onset (12.9 ka), which also contains multiple ET markers comprising the impact layer (the YDB). Surviving animal populations were abruptly reduced at the YDB (e.g., Bison), with major range restrictions and apparent evolutionary bottlenecks. The abruptness of this major extinction is inconsistent with the hypotheses of human overkill and climatic change. We argue that extinction ages older than 12.9 ka for many less common species result from the Signor-Lipps effect, but the impact hypothesis predicts that as new dates are acquired, they will approach ever closer to 12.9 ka. The megafaunal extinction is strongly

  8. 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

  9. Fear Extinction Memory Consolidation Requires Potentiation of Pontine-Wave Activity during REM Sleep

    Science.gov (United States)

    Datta, Subimal; O'Malley, Matthew W .

    2013-01-01

    Sleep plays an important role in memory consolidation within multiple memory systems including contextual fear extinction memory, but little is known about the mechanisms that underlie this process. Here, we show that fear extinction training in rats, which extinguished conditioned fear, increased both slow-wave sleep and rapid-eye movement (REM) sleep. Surprisingly, 24 h later, during memory testing, only 57% of the fear-extinguished animals retained fear extinction memory. We found that these animals exhibited an increase in phasic pontine-wave (P-wave) activity during post-training REM sleep, which was absent in the 43% of animals that failed to retain fear extinction memory. The results of this study provide evidence that brainstem activation, specifically potentiation of phasic P-wave activity, during post-training REM sleep is critical for consolidation of fear extinction memory. The results of this study also suggest that, contrary to the popular hypothesis of sleep and memory, increased sleep after training alone does not guarantee consolidation and/or retention of fear extinction memory. Rather, the potentiation of specific sleep-dependent physiological events may be a more accurate predictor for successful consolidation of fear extinction memory. Identification of this unique mechanism will significantly improve our present understanding of the cellular and molecular mechanisms that underlie the sleep-dependent regulation of emotional memory. Additionally, this discovery may also initiate development of a new, more targeted treatment method for clinical disorders of fear and anxiety in humans that is more efficacious than existing methods such as exposure therapy that incorporate only fear extinction. PMID:23467372

  10. Fear extinction memory consolidation requires potentiation of pontine-wave activity during REM sleep.

    Science.gov (United States)

    Datta, Subimal; O'Malley, Matthew W

    2013-03-06

    Sleep plays an important role in memory consolidation within multiple memory systems including contextual fear extinction memory, but little is known about the mechanisms that underlie this process. Here, we show that fear extinction training in rats, which extinguished conditioned fear, increased both slow-wave sleep and rapid-eye movement (REM) sleep. Surprisingly, 24 h later, during memory testing, only 57% of the fear-extinguished animals retained fear extinction memory. We found that these animals exhibited an increase in phasic pontine-wave (P-wave) activity during post-training REM sleep, which was absent in the 43% of animals that failed to retain fear extinction memory. The results of this study provide evidence that brainstem activation, specifically potentiation of phasic P-wave activity, during post-training REM sleep is critical for consolidation of fear extinction memory. The results of this study also suggest that, contrary to the popular hypothesis of sleep and memory, increased sleep after training alone does not guarantee consolidation and/or retention of fear extinction memory. Rather, the potentiation of specific sleep-dependent physiological events may be a more accurate predictor for successful consolidation of fear extinction memory. Identification of this unique mechanism will significantly improve our present understanding of the cellular and molecular mechanisms that underlie the sleep-dependent regulation of emotional memory. Additionally, this discovery may also initiate development of a new, more targeted treatment method for clinical disorders of fear and anxiety in humans that is more efficacious than existing methods such as exposure therapy that incorporate only fear extinction.

  11. β-Adrenoceptor Blockade in the Basolateral Amygdala, But Not the Medial Prefrontal Cortex, Rescues the Immediate Extinction Deficit.

    Science.gov (United States)

    Giustino, Thomas F; Seemann, Jocelyn R; Acca, Gillian M; Goode, Travis D; Fitzgerald, Paul J; Maren, Stephen

    2017-05-02

    Early psychological interventions, such as exposure therapy, rely on extinction learning to reduce the development of stress- and trauma-related disorders. However, recent research suggests that extinction often fails to reduce fear when administered soon after trauma. This immediate extinction deficit (IED) may be due to stress-induced dysregulation of neural circuits involved in extinction learning. We have shown that systemic β-adrenoceptor blockade with propranolol rescues the IED, but impairs delayed extinction. Here we sought to determine the neural locus of these effects. Rats underwent auditory fear conditioning and then received either immediate (30 min) or delayed (24 h) extinction training. We used bilateral intracranial infusions of propranolol into either the infralimbic division of the medial prefrontal cortex (mPFC) or the basolateral amygdala (BLA) to examine the effects of β-adrenoceptor blockade on immediate and delayed extinction learning. Interestingly, intra-BLA, but not intra-mPFC, propranolol rescued the IED; animals receiving intra-BLA propranolol prior to immediate extinction showed less spontaneous recovery of fear during extinction retrieval. Importantly, this was not due to impaired consolidation of the conditioning memory. In contrast, neither intra-BLA nor intra-mPFC propranolol affected delayed extinction learning. Overall, these data contribute to a growing literature suggesting dissociable roles for key nodes in the fear extinction circuit depending on the timing of extinction relative to conditioning. These data also suggest that heightened noradrenergic activity in the BLA underlies stress-induced extinction deficits. Propranolol may be a useful adjunct to behavioral therapeutic interventions in recently traumatized individuals who are at risk for developing trauma-related disorders.Neuropsychopharmacology advance online publication, 31 May 2017; doi:10.1038/npp.2017.89.

  12. Ice-age megafauna in Arctic Alaska: extinction, invasion, survival

    Science.gov (United States)

    Mann, Daniel H.; Groves, Pamela; Kunz, Michael L.; Reanier, Richard E.; Gaglioti, Benjamin V.

    2013-01-01

    Radical restructuring of the terrestrial, large mammal fauna living in arctic Alaska occurred between 14,000 and 10,000 years ago at the end of the last ice age. Steppe bison, horse, and woolly mammoth became extinct, moose and humans invaded, while muskox and caribou persisted. The ice age megafauna was more diverse in species and possibly contained 6× more individual animals than live in the region today. Megafaunal biomass during the last ice age may have been 30× greater than present. Horse was the dominant species in terms of number of individuals. Lions, short-faced bears, wolves, and possibly grizzly bears comprised the predator/scavenger guild. The youngest mammoth so far discovered lived ca 13,800 years ago, while horses and bison persisted on the North Slope until at least 12,500 years ago during the Younger Dryas cold interval. The first people arrived on the North Slope ca 13,500 years ago. Bone-isotope measurements and foot-loading characteristics suggest megafaunal niches were segregated along a moisture gradient, with the surviving species (muskox and caribou) utilizing the warmer and moister portions of the vegetation mosaic. As the ice age ended, the moisture gradient shifted and eliminated habitats utilized by the dryland, grazing species (bison, horse, mammoth). The proximate cause for this change was regional paludification, the spread of organic soil horizons and peat. End-Pleistocene extinctions in arctic Alaska represent local, not global extinctions since the megafaunal species lost there persisted to later times elsewhere. Hunting seems unlikely as the cause of these extinctions, but it cannot be ruled out as the final blow to megafaunal populations that were already functionally extinct by the time humans arrived in the region.

  13. Evolutionary patterns from mass originations and mass extinctions.

    Science.gov (United States)

    Hewzulla, D; Boulter, M C; Benton, M J; Halley, J M

    1999-01-01

    The Fossil Record 2 database gives a stratigraphic range of most known animal and plant families. We have used it to plot the number of families extant through time and argue for an exponential fit, rather than a logistic one, on the basis of power spectra of the residuals from the exponential. The times of origins and extinctions, when plotted for all families of marine and terrestrial organisms over the last 600 Myr, reveal different origination and extinction peaks. This suggests that patterns of biological evolution are driven by its own internal dynamics as well as responding to upsets from external causes. Spectral analysis shows that the residuals from the exponential model of the marine system are more consistent with 1/f noise suggesting that self-organized criticality phenomena may be involved. PMID:10212492

  14. Increases in Doublecortin Immunoreactivity in the Dentate Gyrus following Extinction of Heroin-Seeking Behavior

    Directory of Open Access Journals (Sweden)

    Megan P. Hicks

    2012-01-01

    Full Text Available Adult-generated neurons in the dentate gyrus (DG of the hippocampus play a role in various forms of learning and memory. However, adult born neurons in the DG, while still at an immature stage, exhibit unique electrophysiological properties and are also functionally implicated in learning and memory processes. We investigated the effects of extinction of drug-seeking behavior on the formation of immature neurons in the DG as assessed by quantification of doublecortin (DCX immunoreactivity. Rats were allowed to self-administer heroin (0.03 mg/kg/infusion for 12 days and then subjected either to 10 days of extinction training or forced abstinence. We also examined extinction responding patterns following heroin self-administration in glial fibrillary acidic protein thymidine kinase (GFAP-tk transgenic mice, which have been previously demonstrated to show reduced formation of immature and mature neurons in the DG following treatment with ganciclovir (GCV. We found that extinction training increased DCX immunoreactivity in the dorsal DG as compared with animals undergoing forced abstinence, and that GCV-treated GFAP-tk mice displayed impaired extinction learning as compared to saline-treated mice. Our results suggest that extinction of drug-seeking behavior increases the formation of immature neurons in the DG and that these neurons may play a functional role in extinction learning.

  15. Increases in doublecortin immunoreactivity in the dentate gyrus following extinction of heroin-seeking behavior.

    Science.gov (United States)

    Hicks, Megan P; Wischerath, Kelly C; Lacrosse, Amber L; Olive, M Foster

    2012-01-01

    Adult-generated neurons in the dentate gyrus (DG) of the hippocampus play a role in various forms of learning and memory. However, adult born neurons in the DG, while still at an immature stage, exhibit unique electrophysiological properties and are also functionally implicated in learning and memory processes. We investigated the effects of extinction of drug-seeking behavior on the formation of immature neurons in the DG as assessed by quantification of doublecortin (DCX) immunoreactivity. Rats were allowed to self-administer heroin (0.03 mg/kg/infusion) for 12 days and then subjected either to 10 days of extinction training or forced abstinence. We also examined extinction responding patterns following heroin self-administration in glial fibrillary acidic protein thymidine kinase (GFAP-tk) transgenic mice, which have been previously demonstrated to show reduced formation of immature and mature neurons in the DG following treatment with ganciclovir (GCV). We found that extinction training increased DCX immunoreactivity in the dorsal DG as compared with animals undergoing forced abstinence, and that GCV-treated GFAP-tk mice displayed impaired extinction learning as compared to saline-treated mice. Our results suggest that extinction of drug-seeking behavior increases the formation of immature neurons in the DG and that these neurons may play a functional role in extinction learning.

  16. High-precision geochronology confirms voluminous magmatism before, during, and after Earth's most severe extinction.

    Science.gov (United States)

    Burgess, Seth D; Bowring, Samuel A

    2015-08-01

    The end-Permian mass extinction was the most severe in the Phanerozoic, extinguishing more than 90% of marine and 75% of terrestrial species in a maximum of 61 ± 48 ky. Because of broad temporal coincidence between the biotic crisis and one of the most voluminous continental volcanic eruptions since the origin of animals, the Siberian Traps large igneous province (LIP), a causal connection has long been suggested. Magmatism is hypothesized to have caused rapid injection of massive amounts of greenhouse gases into the atmosphere, driving climate change and subsequent destabilization of the biosphere. Establishing a causal connection between magmatism and mass extinction is critically dependent on accurately and precisely knowing the relative timing of the two events and the flux of magma. New U/Pb dates on Siberian Traps LIP lava flows, sills, and explosively erupted rocks indicate that (i) about two-thirds of the total lava/pyroclastic volume was erupted over ~300 ky, before and concurrent with the end-Permian mass extinction; (ii) eruption of the balance of lavas continued for at least 500 ky after extinction cessation; and (iii) massive emplacement of sills into the shallow crust began concomitant with the mass extinction and continued for at least 500 ky into the early Triassic. This age model is consistent with Siberian Traps LIP magmatism as a trigger for the end-Permian mass extinction and suggests a role for magmatism in suppression of post-extinction biotic recovery.

  17. Extinction of goal tracking also eliminates the conditioned reinforcing effects of an appetitive conditioned stimulus.

    Science.gov (United States)

    Kearns, David N; Tunstall, Brendan J; Marks, Katherine R; Weiss, Stanley J

    2012-02-01

    Previous studies have suggested that the effects of extinction are response-specific. The present study investigated whether an extinction treatment that eliminated goal tracking elicited by an appetitive conditioned stimulus (CS) would also eliminate the conditioned reinforcing effects of that CS. Rats were first trained on a goal-tracking procedure in which an auditory CS was paired with a food unconditioned stimulus. Animals learned to approach the location where the food was delivered. In a subsequent phase, rats in one group received extinction training that eliminated the goal-tracking elicited by the CS. Rats in the other group did not experience extinction of the food-paired CS. Then, both groups received a test for conditioned reinforcement in which leverpresses resulted in the brief presentation of the stimulus previously paired with food. This stimulus did not act as a conditioned reinforcer in the group that had been subjected to extinction training, but did serve as a conditioned reinforcer in the group that did not experience extinction. These results indicate that the effects of extinction generalize from the approach-eliciting to the conditioned reinforcing effects of an appetitive CS.

  18. Sleep deprivation impairs the extinction of cocaine-induced environmental conditioning in mice.

    Science.gov (United States)

    Berro, L F; Hollais, A W; Patti, C L; Fukushiro, D F; Mári-Kawamoto, E; Talhati, F; Costa, J M; Zanin, K A; Lopes-Silva, L B; Ceccon, L M; Santos, R; Procópio-Souza, R; Trombin, T F; Yokoyama, T S; Wuo-Silva, R; Tufik, S; Andersen, M L; Frussa-Filho, R

    2014-09-01

    Persistence of a drug-environment conditioning induced by repeated psychostimulant treatment is thought to play a key role in the addictive cycle. In addition, sleep disorders are a common feature in patients with addictive disorders. Sleep deprivation shares similar neurobiological effects with psychostimulants. Therefore, we investigated whether sleep deprivation would impair the extinction of previously established conditioning between the drug effect and the environmental cues. Four cohorts of male adult mice underwent a behavioral sensitization procedure pairing drug (cocaine at 15 mg/kg, i.p.) or saline with environment (open-field apparatus). The extinction of conditioned locomotion was evaluated after control (home-cage maintained) or sleep deprivation (gentle handling method for 6h) conditions. Sleep deprivation both postponed the initiation and impaired the completeness of extinction of the conditioned locomotion promoted by previous drug-environment conditioning in cocaine-sensitized animals. While the cocaine control group required 5 free-drug sessions of exposure to the open-field apparatus to complete extinction of conditioned locomotion, the cocaine pre-treated group that experienced sleep deprivation before each extinction session still significantly differed from its respective control group on Day 5 of extinction. The possibility that the sleep condition can influence the extinction of a long-lasting association between drug effects and environmental cues can represent new outcomes for clinically relevant phenomena.

  19. Examining the extinction of the Barbary lion and its implications for felid conservation.

    Directory of Open Access Journals (Sweden)

    Simon A Black

    Full Text Available Estimations of species extinction dates are rarely definitive, yet declarations of extinction or extirpation are important as they define when conservation efforts may cease. Erroneous declarations of extinctions not only destabilize conservation efforts but also corrode local community support. Mismatches in perceptions by the scientific and local communities risk undermining sensitive, but important partnerships. We examine observations relating to the decline and extinction of Barbary lions in North Africa. Whilst the extinction predates the era of the scientific conservation movement, the decline is relatively well documented in historical records. Recently unearthed accounts suggest Barbary lions survived later than previously assumed. We use probabilistic methods to estimate a more recent extinction date for the subspecies. The evidence presented for a much later persistence of lions in North Africa, including generations when sightings were nil, suggests caution when considering felid populations as extinct in the wild. The case raises the possibility that captive animals descended from the Moroccan royal collection are closer contemporaries to wild Barbary lions. Furthermore, our results highlight the vulnerability of very small lion populations and the significance of continued conservation of remnant lion populations in Central and West Africa.

  20. 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.

  1. Effects of unconditioned stimulus intensity and fear extinction on subsequent sleep architecture in an afternoon nap.

    Science.gov (United States)

    Sturm, Anna; Czisch, Michael; Spoormaker, Victor I

    2013-12-01

    Impaired fear extinction and disturbed sleep coincide in post-traumatic stress disorder (PTSD), but the nature of this relationship is unclear. Rapid eye movement (REM) sleep deprivation impairs fear extinction recall in rodents and young healthy subjects, and animal models have demonstrated both disrupted sleep after fear conditioning and normalized sleep after extinction learning. As a correlation between unconditioned stimulus (US) responding and subsequent sleep architecture has been observed in healthy subjects, the goal of this study was to test whether US intensity would causally affect subsequent sleep. Twenty-four young healthy subjects underwent a fear conditioning session with skin conductance response measurements before an afternoon session of polysomnographically recorded sleep (up to 120 min) in the sleep laboratory. Two factors were manipulated experimentally in a 2 × 2 design: US (electrical shock) was set at high or low intensity, and subjects did or did not receive an extinction session after fear conditioning. We observed that neither factor affected REM sleep amount, that high US intensity nominally increased sleep fragmentation (more Stage 1 sleep, stage shifts and wake after sleep onset), and that extinction increased Stage 4 amount. Moreover, reduced Stage 1 and increased Stage 4 and REM sleep were associated with subjective sleep quality of the afternoon nap. These results provide evidence for the notion that US intensity and extinction affect subsequent sleep architecture in young healthy subjects, which may provide a translational bridge from findings in animal studies to correlations observed in PTSD patients.

  2. The cost of being valuable: predictors of extinction risk in marine invertebrates exploited as luxury seafood.

    Science.gov (United States)

    Purcell, Steven W; Polidoro, Beth A; Hamel, Jean-François; Gamboa, Ruth U; Mercier, Annie

    2014-04-22

    Extinction risk has been linked to biological and anthropogenic variables. Prediction of extinction risk in valuable fauna may not follow mainstream drivers when species are exploited for international markets. We use results from an International Union for Conservation of Nature Red List assessment of extinction risk in all 377 known species of sea cucumber within the order Aspidochirotida, many of which are exploited worldwide as luxury seafood for Asian markets. Extinction risk was primarily driven by high market value, compounded by accessibility and familiarity (well known) in the marketplace. Extinction risk in marine animals often relates closely to body size and small geographical range but our study shows a clear exception. Conservation must not lose sight of common species, especially those of high value. Greater human population density and poorer economies in the geographical ranges of endangered species illustrate that anthropogenic variables can also predict extinction risks in marine animals. Local-level regulatory measures must prevent opportunistic exploitation of high-value species. Trade agreements, for example CITES, may aid conservation but will depend on international technical support to low-income tropical countries. The high proportion of data deficient species also stresses a need for research on the ecology and population demographics of unglamorous invertebrates.

  3. Status of Baltic grey seals: Population assessment and extinction risk

    Directory of Open Access Journals (Sweden)

    Karin C Harding

    2007-01-01

    Full Text Available The grey seal (Halichoerus grypus population in the Baltic Sea is recovering after a century of bounty hunting and 3 decades of low fertility rates caused by environmental pollution. A conservative estimate of the population size in 2003 was 19,400 animals, and available data suggest an annual rate of increase of 7.5% since 1990. The growing population has led to increased interactions with the fishery, and demands are being raised for the re-introduction of the hunt. We provide a demographic analysis and a risk assessment of the population, and make recommendations on how to decrease the risk of over exploitation. Although hunting increases the risk of quasi-extinction, the risk can be significantly reduced by the choice of a cautious hunting regime. The least hazardous regimes allow no hunting below a ‘security level’ in population size. Obviously, to implement such a hunting regime detailed knowledge of the population size and growth rate is required. It is not possible to estimate “true” risks for quasi-extinction, but we used an approach where the relative difference for different scenarios can be compared. With a security level at 5,000 females, the population quasi-extinction risk increases 50 fold at an annual hunt of 500 females compared with a scenario with no hunting. The risk of quasi-extinction is very sensitive to declines in the mean growth rate and to increased variance in growth rate. The variance in the population estimates over the last 14 years imply that it would take 9 years to detect a declinefrom 1.075 to 1.027 in the rate of population increase. We also show how the age composition of killed animals influences the impact of the hunt. The overall recommendation is that hunting should be kept to a minimum, carefully documented and accompanied by close population monitoring.

  4. A lesson in defining "extinct"

    OpenAIRE

    Asimow, Paul D.

    2014-01-01

    Toni Feder’s Issues and Events news item about the High-Altitude Water Cherenkov Gamma-Ray Observatory under construction in Mexico ( Physics Today, October 2013, page 22) begins by describing the site as “nestled at 4100 m on the slopes of Sierra Negra, an extinct volcano.” However, as the picture accompanying her piece or a cursory examination in Google Earth makes clear, the site is not on the slopes of Sierra Negra. It sits in the saddle between Sierra Negra and its much larger companion ...

  5. How partial reinforcement of food cues affects the extinction and reacquisition of appetitive responses. A new model for dieting success?

    Science.gov (United States)

    van den Akker, Karolien; Havermans, Remco C; Bouton, Mark E; Jansen, Anita

    2014-10-01

    Animals and humans can easily learn to associate an initially neutral cue with food intake through classical conditioning, but extinction of learned appetitive responses can be more difficult. Intermittent or partial reinforcement of food cues causes especially persistent behaviour in animals: after exposure to such learning schedules, the decline in responding that occurs during extinction is slow. After extinction, increases in responding with renewed reinforcement of food cues (reacquisition) might be less rapid after acquisition with partial reinforcement. In humans, it may be that the eating behaviour of some individuals resembles partial reinforcement schedules to a greater extent, possibly affecting dieting success by interacting with extinction and reacquisition. Furthermore, impulsivity has been associated with less successful dieting, and this association might be explained by impulsivity affecting the learning and extinction of appetitive responses. In the present two studies, the effects of different reinforcement schedules and impulsivity on the acquisition, extinction, and reacquisition of appetitive responses were investigated in a conditioning paradigm involving food rewards in healthy humans. Overall, the results indicate both partial reinforcement schedules and, possibly, impulsivity to be associated with worse extinction performance. A new model of dieting success is proposed: learning histories and, perhaps, certain personality traits (impulsivity) can interfere with the extinction and reacquisition of appetitive responses to food cues and they may be causally related to unsuccessful dieting.

  6. The role of veterinary epidemiology in combating infectious animal diseases on a global scale: the impact of training and outreach programs.

    Science.gov (United States)

    Salman, M D

    2009-12-01

    The effectiveness of detection and control of highly contagious animal diseases is dependent on a solid understanding of their nature and implementation of scientifically sound methods by people who are well trained. The implementation of specific detection methods and tools requires training and application in natural as well as field conditions. The aim of this paper is to present the design and implementation of training in disease investigation and basic veterinary epidemiology in selected countries using the Highly Pathogenic Avian Influenza (HPAI) H5N1 Asia strain as a disease detection model. Indonesia, Egypt, Nigeria, Turkey, and Vietnam were each identified as either a priority country where AI was spreading rapidly or a country at risk for infection. In each of these countries, a training program on epidemiological concepts, field investigation methodology, and detection of H5N1 Asia strain cases was conducted. This report includes the impact of these training sessions on national animal health programs, including follow-up activities of animal health officers who went through these training sessions.

  7. The context dependency of extinction negates the effectiveness of cognitive enhancement to reduce cocaine-primed reinstatement.

    Science.gov (United States)

    Hammond, Sherri; Wagner, John J

    2013-09-01

    With respect to the treatment of addiction, the objective of extinction training is to decrease drug-seeking behavior by repeatedly exposing the patient to cues in the absence of unconditioned reinforcement. Such exposure therapy typically takes place in a novel (clinical) environment. This is potentially problematic, as the effects of extinction training include a context dependent component and therefore diminished efficacy is expected upon the patient's return to former drug-seeking/taking environments. We have reported that treatment with the NMDAR coagonist d-serine is effective in facilitating the effects of extinction to reduce cocaine-primed reinstatement. The present study assesses d-serine's effectiveness in reducing drug-primed reinstatement under conditions in which extinction training occurs in a novel environment. After 22 days of cocaine self-administration (0.5 mg/kg) in context "A", animals underwent 5 extinction training sessions in context "B". Immediately after each extinction session in "B", animals received either saline or d-serine (60 mg/kg) treatment. Our results indicate that d-serine treatment following extinction in "B" had no effect on either IV or IP cocaine-primed reinstatement conducted in "A". These results stand in contrast to our previous findings where extinction occurred in "A", indicating that d-serine's effectiveness in facilitating extinction training to reduce drug-primed reinstatement is not transferable to a novel extinction environment. This inability of d-serine treatment to reduce the context specificity of extinction training may explain the inconsistent effects observed in clinical studies published to date in which adjunctive cognitive enhancement treatment has been combined with behavioral therapy without significant benefit.

  8. Extinction by the long dielectric needles

    CERN Document Server

    Cherkas, Nadejda L

    2016-01-01

    Electromagnetic wave extinction by the very long but finite dielectric needle is compared with that by the infinite dielectric cylinder for an oblique incidence of the electromagnetic wave. It is shown that the renormalized Hankel functions without the logarithmic terms should be used for the calculation of the extinction per unit length of the infinite dielectric cylinder to apply it for extinction calculations by the finite dielectric cylinder.

  9. Resistance to extinction and behavioral momentum

    OpenAIRE

    Nevin, John A.

    2012-01-01

    In the metaphor of behavioral momentum, reinforcement is assumed to strengthen discriminated operant behavior in the sense of increasing its resistance to disruption, and extinction is viewed as disruption by contingency termination and reinforcer omission. In multiple schedules of intermittent reinforcement, resistance to extinction is an increasing function of reinforcer rate, consistent with a model based on the momentum metaphor. The partial-reinforcement extinction effect, which opposes ...

  10. Mass Extinctions vs. Uniformitarianism in Biological Evolution

    OpenAIRE

    Bak, Per; Paczuski, Maya

    1996-01-01

    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 coevolving species. The models exhibit self-organized criti...

  11. Extinction Maps in the WFAU Archives

    CERN Document Server

    Cross, Nicholas

    2015-01-01

    A brief set of notes about the database design for 3D maps of dust extinction in the WFAU Archives, which support data from UKIRT-WFCAM, VISTA and VST. The notes also detail typical use cases, such as getting colour-excesses, extinction-corrections, spectral energy distributions and colour-magnitude diagrams and demonstrate the SQL queries to return data, along with examples from VVV DR2 with bulge extinction maps from Chen et al. (2013).

  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. 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.

  14. Impaired extinction of fear conditioning after REM deprivation is magnified by rearing in an enriched environment.

    Science.gov (United States)

    Hunter, Amy Silvestri

    2015-07-01

    Evidence from both human and animal studies indicates that rapid eye movement sleep (REM) is essential for the acquisition and retention of information, particularly of an emotional nature. Learning and memory can also be impacted by manipulation of housing condition such as exposure to an enriched environment (EE). This study investigated the effects of REM deprivation and EE, both separately and combined, on the extinction of conditioned fear in rats. Consistent with prior studies, conditioning was enhanced in EE-reared rats and extinction was impaired in REM deprived rats. In addition, rats exposed to both REM deprivation and EE showed the greatest impairment in extinction, with effects persisting through the first two days of extinction training. This study is the first to explore the combination of REM deprivation and EE and suggests that manipulations that alter sleep, particularly REM, can have persisting deleterious effects on emotional memory processing.

  15. Rationale, design and methods for a randomised and controlled trial to evaluate "Animal Fun" - a program designed to enhance physical and mental health in young children

    Directory of Open Access Journals (Sweden)

    McLaren Sue

    2010-11-01

    Full Text Available Abstract Background Children with poor motor ability have been found to engage less in physical activities than other children, and a lack of physical activity has been linked to problems such as obesity, lowered bone mineral density and cardiovascular risk factors. Furthermore, if children are confident with their fine and gross motor skills, they are more likely to engage in physical activities such as sports, crafts, dancing and other physical activity programs outside of the school curriculum which are important activities for psychosocial development. The primary objective of this project is to comprehensively evaluate a whole of class physical activity program called Animal Fun designed for Pre-Primary children. This program was designed to improve the child's movement skills, both fine and gross, and their perceptions of their movement ability, promote appropriate social skills and improve social-emotional development. Methods The proposed randomized and controlled trial uses a multivariate nested cohort design to examine the physical (motor coordination and psychosocial (self perceptions, anxiety, social competence outcomes of the program. The Animal Fun program is a teacher delivered universal program incorporating animal actions to facilitate motor skill and social skill acquisition and practice. Pre-intervention scores on motor and psychosocial variables for six control schools and six intervention schools will be compared with post-intervention scores (end of Pre-Primary year and scores taken 12 months later after the children's transition to primary school Year 1. 520 children aged 4.5 to 6 years will be recruited and it is anticipated that 360 children will be retained to the 1 year follow-up. There will be equal numbers of boys and girls. Discussion If this program is found to improve the child's motor and psychosocial skills, this will assist in the child's transition into the first year of school. As a result of these changes

  16. 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.

  17. 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...... 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...

  18. Secondary extinction in Pavlovian fear conditioning.

    Science.gov (United States)

    Vurbic, Drina; Bouton, Mark E

    2011-09-01

    Pavlov (1927/1960) reported that following the conditioning of several stimuli, extinction of one conditioned stimulus (CS) attenuated responding to others that had not undergone direct extinction. However, this secondary extinction effect has not been widely replicated in the contemporary literature. In three conditioned suppression experiments with rats, we further explored the phenomenon. In Experiment 1, we asked whether secondary extinction is more likely to occur with target CSs that have themselves undergone some prior extinction. A robust secondary extinction effect was obtained with a nonextinguished target CS. Experiment 2 showed that extinction of one CS was sufficient to reduce renewal of a second CS when it was tested in a neutral (nonextinction) context. In Experiment 3, secondary extinction was observed in groups that initially received intermixed conditioning trials with the target and nontarget CSs, but not in groups that received conditioning of the two CSs in separate sessions. The results are consistent with the hypothesis that CSs must be associated with a common temporal context during conditioning for secondary extinction to occur.

  19. Dust Extinction in Compact Planetary Nebulae

    OpenAIRE

    Lee, TH; Kwok, S.

    2005-01-01

    The effects of dust extinction on the departure from axisymmetry in the morphology of planetary nebulae (PNs) are investigated through a comparison of the radio free-free emission and hydrogen recombination line images. The dust extinction maps from five compact PNs are derived using high-resolution (̃0"1) Hα and radio maps of the HST and VLA. These extinction maps are then analyzed by an ellipsoidal shell ionization model including the effects of dust extinction to infer the nebulae's intrin...

  20. 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...... extinctions, but global quantitative evidence for this hypothesis is still lacking. We test the potential role of global climate change on the extinction of mammals during the Late Quaternary. Our results suggest that continents with the highest climate footprint values, in other words, with climate changes...

  1. 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...

  2. Extinction-Optimized Volume Illumination.

    Science.gov (United States)

    Ament, Marco; Zirr, Tobias; Dachsbacher, Carsten

    2016-05-16

    We present a novel method to optimize the attenuation of light for the single scattering model in direct volume rendering. A common problem of single scattering is the high dynamic range between lit and shadowed regions due to the exponential attenuation of light along a ray. Moreover, light is often attenuated too strong between a sample point and the camera, hampering the visibility of important features. Our algorithm employs an importance function to selectively illuminate important structures and make them visible from the camera. With the importance function, more light can be transmitted to the features of interest, while contextual structures cast shadows which provide visual cues for perception of depth. At the same time, more scattered light is transmitted from the sample point to the camera to improve the primary visibility of important features. We formulate a minimization problem that automatically determines the extinction along a view or shadow ray to obtain a good balance between sufficient transmittance and attenuation. In contrast to previous approaches, we do not require a computationally expensive solution of a global optimization, but instead provide a closed-form solution for each sampled extinction value along a view or shadow ray and thus achieve interactive performance.

  3. Replication-Independent Histone Variant H3.3 Controls Animal Lifespan through the Regulation of Pro-longevity Transcriptional Programs

    Directory of Open Access Journals (Sweden)

    Antonia Piazzesi

    2016-10-01

    Full Text Available Chromatin structure orchestrates the accessibility to the genetic material. Replication-independent histone variants control transcriptional plasticity in postmitotic cells. The life-long accumulation of these histones has been described, yet the implications on organismal aging remain elusive. Here, we study the importance of the histone variant H3.3 in Caenorhabditis elegans longevity pathways. We show that H3.3-deficient nematodes have negligible lifespan differences compared to wild-type animals. However, H3.3 is essential for the lifespan extension of C. elegans mutants in which pronounced transcriptional changes control longevity programs. Notably, H3.3 loss critically affects the expression of a very large number of genes in long-lived nematodes, resulting in transcriptional profiles similar to wild-type animals. We conclude that H3.3 positively contributes to diverse lifespan-extending signaling pathways, with potential implications on age-related processes in multicellular organisms.

  4. Phylogenetic Clustering of Origination and Extinction across the Late Ordovician Mass Extinction.

    Directory of Open Access Journals (Sweden)

    Andrew Z Krug

    Full Text Available Mass extinctions can have dramatic effects on the trajectory of life, but in some cases the effects can be relatively small even when extinction rates are high. For example, the Late Ordovician mass extinction is the second most severe in terms of the proportion of genera eliminated, yet is noted for the lack of ecological consequences and shifts in clade dominance. By comparison, the end-Cretaceous mass extinction was less severe but eliminated several major clades while some rare surviving clades diversified in the Paleogene. This disconnect may be better understood by incorporating the phylogenetic relatedness of taxa into studies of mass extinctions, as the factors driving extinction and recovery are thought to be phylogenetically conserved and should therefore promote both origination and extinction of closely related taxa. Here, we test whether there was phylogenetic selectivity in extinction and origination using brachiopod genera from the Middle Ordovician through the Devonian. Using an index of taxonomic clustering (RCL as a proxy for phylogenetic clustering, we find that A both extinctions and originations shift from taxonomically random or weakly clustered within families in the Ordovician to strongly clustered in the Silurian and Devonian, beginning with the recovery following the Late Ordovician mass extinction, and B the Late Ordovician mass extinction was itself only weakly clustered. Both results stand in stark contrast to Cretaceous-Cenozoic bivalves, which showed significant levels of taxonomic clustering of extinctions in the Cretaceous, including strong clustering in the mass extinction, but taxonomically random extinctions in the Cenozoic. The contrasting patterns between the Late Ordovician and end-Cretaceous events suggest a complex relationship between the phylogenetic selectivity of mass extinctions and the long-term phylogenetic signal in origination and extinction patterns.

  5. Selectivity of terrestrial gastropod extinctions on an oceanic archipelago and insights into the anthropogenic extinction process

    OpenAIRE

    Chiba, Satoshi; Roy, Kaustuv

    2011-01-01

    Anthropogenic impacts have led to widespread extinctions of species on oceanic islands but the nature of many of these extinctions remains poorly known. Here we investigate extinction selectivities of terrestrial gastropods from the Ogasawara archipelago in the northwest Pacific, where anthropogenic threats have changed over time, shifting primarily from the effects of habitat loss to predation by a variety of different predators. Across all of the islands, extinct species had significantly s...

  6. Biotecnologia animal

    Directory of Open Access Journals (Sweden)

    Luiz Lehmann Coutinho

    2010-01-01

    identification of the genomic region that contains the genes, but the confidence interval of the regions is usually large and may contain several genes. Candidate gene approach is limited to our restricted knowledge of the biological function of the genes. Sequencing of genomes and expressed sequences tags can provide identifying gene position and metabolic pathways associated with phenotypic trait. Integrating these strategies using bioinformatics software will allow identifying of novel genes for animal production. Then, animal breeding programs will include the information from DNA directly on evaluation of genetic value of livestock production.

  7. Stimulus magnitude effects on the extinction of conditioned consummatory responses to flavored sucrose solution in mice.

    Science.gov (United States)

    Pellegrini, Santiago

    2011-06-01

    Paradoxical extinction effects in the conditioned consummatory behavior of rodents have remained largely elusive. Here, appetitive flavor conditioning was studied to determine if a paradoxical magnitude of reinforcement extinction effect (MREE) can occur in the consummatory behavior of mice. During acquisition training of two experiments with factorial design, animals received daily access to either 32% or 4% sucrose solution, and goal tracking time was measured in one-minute bins. In Experiment 1 the solutions were flavored with either 5% or 0.5% almond essence and in Experiment 2 with 2% almond essence, but combined with continuous or partial schedules of reinforcement. During extinction tests of Experiment 1 and 2, water flavored with 0.5% or 2% almond was presented, respectively. Consummatory performance decreased more abruptly during the initial portion of the extinction sessions after training with 32% as compared to 4% sucrose solution. Furthermore, when given a choice test after extinction training (Experiment 2), animals trained with 32% sucrose, preferred the flavored solution, but animals trained with 4% preferred the unflavored solution. These results are interpreted as indicative of the occurrence of a paradoxical MREE in conditioned consummatory behaviors.

  8. 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…

  9. Antidepressants reduce extinction-induced withdrawal and biting behaviors: a model for depressive-like behavior.

    Science.gov (United States)

    Huston, J P; van den Brink, J; Komorowski, M; Huq, Y; Topic, B

    2012-05-17

    The withholding of expected rewards results in extinction of behavior and, hypothetically, to depression-like symptoms. In a test of this hypothesis, we examined the effects of extinction of food-reinforced lever-pressing on collateral behaviors that might be indices of depression. Operant extinction is known to be aversive to the organism and results in avoidance behavior. We hypothesized that avoidance of, or withdrawal from, the former source of reward may serve as a marker for "despair." Adult male Wistar rats (n=6-7 animals per group) were exposed to a Skinner box attached to a second compartment of the same size, providing opportunity for the animals to leave the operant chamber and to enter the "withdrawal" compartment. The animals spent a portion of the time during the extinction trials in this second chamber. To assess the predictive validity of this behavior as a potential marker of "despair," we tested the effects of chronic administration of two common antidepressant drugs on this measure. The tricyclic antidepressant imipramine (20 mg/kg) as well as the selective serotonin reuptake inhibitor citalopram (20 mg/kg) reduced the number of entries and time spent in the withdrawal compartment. We propose that entries into and time spent in the withdrawal compartment may operationalize "avoidance," a core symptom of major depression. Rearing as well as biting behaviors during the extinction trials were also attenuated by the antidepressant treatment. These results lend support to the hypothesis that extinction of positively reinforced operants evokes behaviors that reflect elements of "despair/depression" because these behaviors are modulated by antidepressant treatment. The avoidance of the operant chamber as a consequence of extinction, together with rearing and biting behaviors, may serve as useful measures for the testing of antidepressant treatments.

  10. Aerobic Marine Habitat Loss During the Late Permian Extinction

    Science.gov (United States)

    Penn, J. L.; Deutsch, C.; Payne, J.; Sperling, E. A.

    2016-12-01

    Rapid climate change at the end of the Permian is thought to have triggered the most severe mass extinction in Earth's history, but the precise mechanism of biodiversity loss is unknown. Geological evidence points to lethally hot equatorial temperatures and an expansion of anoxic ocean waters as likely culprits. However, previous climate model simulations of the warm Early Triassic exhibit weak tropical warming, and anoxic conditions require a massive and unconstrained increase in the ocean nutrient reservoir. Reconciling model predictions with the geologic record remains a key challenge to identifying the kill-mechanism, which must also take into account the role of animal physiology. Here we apply a recently developed index for the metabolic scope of marine animals to the first global climate simulations of the Permian-Triassic transition to quantify the effects of ocean warming and oxygen (O2) depletion on aerobic habitat availability. Forcing with extreme CO2 concentrations warms the surface ocean by over 10oC, consistent with paleoproxies for upper ocean temperature change. Warming depletes global O2, with greatest losses occuring in tropical deep waters as a result of their reduced ventilation. Together warming and deoxygenation would have constricted the occurrence of marine habitat by 80% globally, by decreasing the metabolic index of the Permian ocean. These changes are most pronounced in the tropics where the fossil record suggests recovery was severely inhibited. Fossil deposits also record changes in animal body size across the extinction. We find that adaptation via body size reductions can compensate for increasing hypoxia at high latitudes, and even prevent extinction there, but cannot maintain the habitability of the tropics.

  11. 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…

  12. Levels of polychlorinated dibenzo-p-dioxins and dibenzofurans in food of animal origin. The Swiss dioxin monitoring program.

    Science.gov (United States)

    Schmid, Peter; Gujer, Erika; Degen, Silvia; Zennegg, Markus; Kuchen, Arnold; Wüthrich, Claude

    2002-12-04

    Between 1997 and 1999, several cases of dioxin contaminations in foodstuffs of animal origin occurred in Europe due to feed contaminated by several independent sources: citrus pulp pellets, fat containing polychlorinated biphenyls (PCB), and kaolinitic clay as anti-caking agent in feedingstuffs. As a consequence of the latter, a survey on polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) in food of animal origin was initiated by the Swiss authorities to assess the extent of PCDD/F contamination and to document the efficiency of the measures taken to ensure the decontamination of the food supply. Investigation of a total of 128 samples of cow's milk, poultry, eggs, and meat revealed several cases of residue levels distinctly above the background exposure limit of approximately 2.5 ng of I-TEQ/kg (fat basis). Particularly, elevated concentrations were found in eggs (maximum 13 ng of I-TEQ/kg), poultry (maximum 3.9 ng of I-TEQ/kg), and pork (maximum 7.5 ng of I-TEQ/kg). On the basis of the observed PCDD/F congener pattern, the contamination could be attributed to PCDD/F-contaminated kaolin that was used as an anti-caking agent in particular feedstuffs.

  13. 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);…

  14. Can Parallelingualism Save Norwegian from Extinction?

    Science.gov (United States)

    Linn, Andrew R.

    2010-01-01

    Language extinction is one of the most pressing issues in linguistics today, and the literature is full of discussion about how to combat it. Statements that Norwegian is amongst the languages that are already extinct are merely examples of a widespread tendency in the literature towards erroneous information about Norwegian. Nonetheless, there is…

  15. 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.

  16. The Mid-Infrared Extinction Law in the Ophiuchus, Perseus, and Serpens Molecular Clouds

    CERN Document Server

    Chapman, Nicholas L; Lai, Shih-Ping; Evans, Neal J

    2008-01-01

    We compute the mid-infrared extinction law from 3.6-24 microns in three molecular clouds: Ophiuchus, Perseus, and Serpens, by combining data from the "Cores to Disks" Spitzer Legacy Science program with deep JHKs imaging. Using a new technique, we are able to calculate the line-of-sight extinction law towards each background star in our fields. With these line-of-sight measurements, we create, for the first time, maps of the chi-squared deviation of the data from two extinction law models. Because our chi-squared maps have the same spatial resolution as our extinction maps, we can directly observe the changing extinction law as a function of the total column density. In the Spitzer IRAC bands, 3.6-8 microns, we see evidence for grain growth. Below $A_{K_s} = 0.5$, our extinction law is well-fit by the Weingartner & Draine (2001) $R_V = 3.1$ diffuse interstellar medium dust model. As the extinction increases, our law gradually flattens, and for $A_{K_s} >= 1$, the data are more consistent with the Weingart...

  17. Animal genetic resources in Brazil: result of five centuries of natural selection.

    Science.gov (United States)

    Mariante, A da S; Egito, A A

    2002-01-01

    Brazil has various species of domestic animals, which developed from breeds brought by the Portuguese settlers soon after their discovery. For five centuries, these breeds have been subjected to natural selection in specific environments. Today, they present characteristics adapted to the specific Brazilian environmental conditions. These breeds developed in Brazil are known as "Crioulo," "local," or naturalized. From the beginning of the 20th century, some exotic breeds, selected in temperate regions, have begun to be imported. Although more productive, these breeds do not have adaptive traits, such as resistance to disease and parasites found in breeds considered to be "native." Even so, little by little, they replaced the native breeds, to such an extent that the latter are in danger of extinction. In 1983, to avoid the loss of this important genetic material, the National Research Center for Genetic Resources and Biotechnology (Cenargen) of the Brazilian Agricultural Research Corporation (Embrapa) decided to include conservation of animal genetic resources in its research program Conservation and Utilization of Genetic Resources. Until this time, they were only concerned with conservation of native plants. Conservation has been carried out by various research centers of Embrapa, universities, state research corporations, and private farmers, with a single coordinator at the national level, Cenargen. Specifically, conservation is being carried out by conservation nuclei, which are specific herds in which the animals are being conserved, situated in the habitats where the animals have been subjected to natural selection. This involves storage of semen and embryos from cattle, horses, buffaloes, donkeys, goats, sheep, and pigs. The Brazilian Animal Germplasm Bank is kept at Cenargen, which is responsible for the storage of semen and embryos of various breeds of domestic animals threatened with extinction, where almost 45,000 doses of semen and more than 200

  18. Was ocean acidification responsible for history's greatest extinction?

    Science.gov (United States)

    Schultz, Colin

    2011-11-01

    Two hundred fifty million years ago, the world suffered the greatest recorded extinction of all time. More than 90% of marine animals and a majority of terrestrial species disappeared, yet the cause of the Permian-Triassic boundary (PTB) dieoff remains unknown. Various theories abound, with most focusing on rampant Siberian volcanism and its potential consequences: global warming, carbon dioxide poisoning, ocean acidification, or the severe drawdown of oceanic dissolved oxygen levels, also known as anoxia. To narrow the range of possible causes, Montenegro et al. ran climate simulations for PTB using the University of Victoria Earth System Climate Model, a carbon cycle-climate coupled general circulation model.

  19. Synchronous extinction of North America's Pleistocene mammals

    Science.gov (United States)

    Faith, J. Tyler; Surovell, Todd A.

    2009-12-01

    The late Pleistocene witnessed the extinction of 35 genera of North American mammals. The last appearance dates of 16 of these genera securely fall between 12,000 and 10,000 radiocarbon years ago (≈13,800-11,400 calendar years B.P.), although whether the absence of fossil occurrences for the remaining 19 genera from this time interval is the result of sampling error or temporally staggered extinctions is unclear. Analysis of the chronology of extinctions suggests that sampling error can explain the absence of terminal Pleistocene last appearance dates for the remaining 19 genera. The extinction chronology of North American Pleistocene mammals therefore can be characterized as a synchronous event that took place 12,000-10,000 radiocarbon years B.P. Results favor an extinction mechanism that is capable of wiping out up to 35 genera across a continent in a geologic instant.

  20. 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.

  1. Animal ethics dilemma

    DEFF Research Database (Denmark)

    Dich, Trine; Hansen, Tina; Algers, Anne

    2006-01-01

    'Animal Ethics Dilemma' is a freely available computer-supported learning tool (www.animalethicsdilemma.net or www.aedilemma.net) which has been developed primarily for veterinary undergraduates but is applicable also to students in other fields of animal science. The objectives of the computer...... program are to promote students' understanding of the ethics related to animal use, to illustrate ethical dilemmas that arise in animal use, to broaden students' moral imagination, and to enable students to differentiate between types of ethical argument. The program comprises five case studies: (1......) the blind hens; (2) ANDi the genetically modified monkey; (3) euthanasia of a healthy dog; (4) animal slaughter; and (5) rehabilitation of seals. Special consideration has been given to enhancing the pedagogic value of the program. Students can control their learning by selecting a variety of ways...

  2. Rethinking Trade-Driven Extinction Risk in Marine and Terrestrial Megafauna.

    Science.gov (United States)

    McClenachan, Loren; Cooper, Andrew B; Dulvy, Nicholas K

    2016-06-20

    Large animals hunted for the high value of their parts (e.g., elephant ivory and shark fins) are at risk of extinction due to both intensive international trade pressure and intrinsic biological sensitivity. However, the relative role of trade, particularly in non-perishable products, and biological factors in driving extinction risk is not well understood [1-4]. Here we identify a taxonomically diverse group of >100 marine and terrestrial megafauna targeted for international luxury markets; estimate their value across three points of sale; test relationships among extinction risk, high value, and body size; and quantify the effects of two mitigating factors: poaching fines and geographic range size. We find that body size is the principal driver of risk for lower value species, but that this biological pattern is eliminated above a value threshold, meaning that the most valuable species face a high extinction risk regardless of size. For example, once mean product values exceed US$12,557 kg(-1), body size no longer drives risk. Total value scales with size for marine animals more strongly than for terrestrial animals, incentivizing the hunting of large marine individuals and species. Poaching fines currently have little effect on extinction risk; fines would need to be increased 10- to 100-fold to be effective. Large geographic ranges reduce risk for terrestrial, but not marine, species, whose ranges are ten times greater. Our results underscore both the evolutionary and ecosystem consequences of targeting large marine animals and the need to geographically scale up and prioritize conservation of high-value marine species to avoid extinction.

  3. Spiral Phyllotaxis Pattern in an Animal Cell: A Fluid- Driven Mechanism for Red Cell Echinocytosis and Programmed Cell Death

    OpenAIRE

    Lofthouse, J. T.

    2004-01-01

    This paper demonstrates that the pattern of lipid spiculesthat emerge on the surface of red blood cells in the classic 'Discocyte to Echinocyte' shape change is a generative spiral, and presents a qualitative, fluid- driven mechanism for their production, compatible with the work of Douady and Couder. Implications for the dynamics of cell growth, plant cell phyllotaxy, programmed cell death and gravity sensitivity are explained in terms of a new qualitative model of cellular fluid dynamics.

  4. Early-life adversity-induced long-term epigenetic programming associated with early onset of chronic physical aggression: Studies in humans and animals.

    Science.gov (United States)

    Chistiakov, Dimitry A; Chekhonin, Vladimir P

    2017-06-05

    To examine whether chronic physical aggression (CPA) in adulthood can be epigenetically programmed early in life due to exposure to early-life adversity. Literature search of public databases such as PubMed/MEDLINE and Scopus. Children/adolescents susceptible for CPA and exposed to early-life abuse fail to efficiently cope with stress that in turn results in the development of CPA later in life. This phenomenon was observed in humans and animal models of aggression. The susceptibility to aggression is a complex trait that is regulated by the interaction between environmental and genetic factors. Epigenetic mechanisms mediate this interaction. Subjects exposed to stress early in life exhibited long-term epigenetic programming that can influence their behaviour in adulthood. This programming affects expression of many genes not only in the brain but also in other systems such as neuroendocrine and immune. The propensity to adult CPA behaviour in subjects experienced to early-life adversity is mediated by epigenetic programming that involves long-term systemic epigenetic alterations in a whole genome.

  5. Extinction chronology of the cave lion Panthera spelaea

    Science.gov (United States)

    Stuart, Anthony J.; Lister, Adrian M.

    2011-08-01

    The cave lion, Panthera spelaea, was widespread across northern Eurasia and Alaska/Yukon during the Late Pleistocene. Both morphology and DNA indicate an animal distinct from modern lions (probably at the species level) so that its disappearance in the Late Pleistocene should be treated as a true extinction. New AMS radiocarbon dates directly on cave lion from across its range, together with published dates from other studies - totalling 111 dates - indicate extinction across Eurasia in the interval ca. 14-14.5 cal ka BP, and in Alaska/Yukon about a thousand years later. It is likely that its extinction occurred directly or indirectly in response to the climatic warming that occurred ca. 14.7 cal ka BP at the onset of Greenland Interstadial 1, accompanied by a spread of shrubs and trees and reduction in open habitats. Possibly there was also a concomitant reduction in abundance of available prey, although most of its probable prey species survived substantially later. At present it is unclear whether human expansion in the Lateglacial might have played a role in cave lion extinction. Gaps in the temporal pattern of dates suggest earlier temporary contractions of range, ca. 40-35 cal ka BP in Siberia (during MIS 3) and ca. 25-20 cal ka BP in Europe (during the 'Last Glacial Maximum'), but further dates are required to corroborate these. The Holocene expansion of modern lion ( Panthera leo) into south-west Asia and south-east Europe re-occupied part of the former range of P. spelaea, but the Late Pleistocene temporal and geographical relationships of the two species are unknown.

  6. Seed dispersal anachronisms: rethinking the fruits extinct megafauna ate.

    Directory of Open Access Journals (Sweden)

    Paulo R Guimarães

    Full Text Available BACKGROUND: Some neotropical, fleshy-fruited plants have fruits structurally similar to paleotropical fruits dispersed by megafauna (mammals > 10(3 kg, yet these dispersers were extinct in South America 10-15 Kyr BP. Anachronic dispersal systems are best explained by interactions with extinct animals and show impaired dispersal resulting in altered seed dispersal dynamics. METHODOLOGY/PRINCIPAL FINDINGS: We introduce an operational definition of megafaunal fruits and perform a comparative analysis of 103 Neotropical fruit species fitting this dispersal mode. We define two megafaunal fruit types based on previous analyses of elephant fruits: fruits 4-10 cm in diameter with up to five large seeds, and fruits > 10 cm diameter with numerous small seeds. Megafaunal fruits are well represented in unrelated families such as Sapotaceae, Fabaceae, Solanaceae, Apocynaceae, Malvaceae, Caryocaraceae, and Arecaceae and combine an overbuilt design (large fruit mass and size with either a single or few ( 100 seeds. Within-family and within-genus contrasts between megafaunal and non-megafaunal groups of species indicate a marked difference in fruit diameter and fruit mass but less so for individual seed mass, with a significant trend for megafaunal fruits to have larger seeds and seediness. CONCLUSIONS/SIGNIFICANCE: Megafaunal fruits allow plants to circumvent the trade-off between seed size and dispersal by relying on frugivores able to disperse enormous seed loads over long-distances. Present-day seed dispersal by scatter-hoarding rodents, introduced livestock, runoff, flooding, gravity, and human-mediated dispersal allowed survival of megafauna-dependent fruit species after extinction of the major seed dispersers. Megafauna extinction had several potential consequences, such as a scale shift reducing the seed dispersal distances, increasingly clumped spatial patterns, reduced geographic ranges and limited genetic variation and increased among

  7. Animal research

    DEFF Research Database (Denmark)

    Olsson, I.A.S.; Sandøe, Peter

    2012-01-01

    in research is analyzed from the viewpoint of three distinct ethical approaches: contractarianism, utilitarianism, and animal rights view. On a contractarian view, research on animals is only an ethical issue to the extent that other humans as parties to the social contract care about how research animals......This article presents the ethical issues in animal research using a combined approach of ethical theory and analysis of scientific findings with bearing on the ethical analysis. The article opens with a general discussion of the moral acceptability of animal use in research. The use of animals...... are faring. From the utilitarian perspective, the use of sentient animals in research that may harm them is an ethical issue, but harm done to animals can be balanced by benefit generated for humans and other animals. The animal rights view, when thoroughgoing, is abolitionist as regards the use of animals...

  8. Animal ethics dilemma

    DEFF Research Database (Denmark)

    Dich, Trine; Hansen, Tina; Algers, Anne

    2006-01-01

    'Animal Ethics Dilemma' is a freely available computer-supported learning tool (www.animalethicsdilemma.net or www.aedilemma.net) which has been developed primarily for veterinary undergraduates but is applicable also to students in other fields of animal science. The objectives of the computer...... program are to promote students' understanding of the ethics related to animal use, to illustrate ethical dilemmas that arise in animal use, to broaden students' moral imagination, and to enable students to differentiate between types of ethical argument. The program comprises five case studies: (1...... to explore the program; for example, they can navigate the program using the 'Assist Me' option, which explains the basis of the ethical arguments. Reality text provides details of real events on which the case is based, and a glossary of terminology is available for the students to explore. Selected access...

  9. Algorithm Animation with Galant.

    Science.gov (United States)

    Stallmann, Matthias F

    2017-01-01

    Although surveys suggest positive student attitudes toward the use of algorithm animations, it is not clear that they improve learning outcomes. The Graph Algorithm Animation Tool, or Galant, challenges and motivates students to engage more deeply with algorithm concepts, without distracting them with programming language details or GUIs. Even though Galant is specifically designed for graph algorithms, it has also been used to animate other algorithms, most notably sorting algorithms.

  10. Is Global Anoxia an Alternative Cause for the Hirnantian Mass Extinction?

    Science.gov (United States)

    De Weirdt, Julie; Vandenbroucke, Thijs; Emsbo, Poul; McLaughlin, Patrick; Delabroye, Aurélien; Munnecke, Axel; Desrochers, André

    2017-04-01

    Cooling and glacial episodes have long been considered the main driver of Late Ordovician-Silurian (mass) extinction events that coincide with δ13Ccarb excursions. However, emerging evidence for protracted cooling during most of the Ordovician and the misalignment between major regressions and faunal turnovers in the Upper Ordovician, suggests a more complex relation between glaciations and extinctions. Emsbo et al. (2010, GSA Abstracts with Programs) demonstrated dramatic enrichments in redox sensitive metals during the early Wenlock Ireviken extinction event and suggested ocean anoxia as an alternative kill-mechanism. Vandenbroucke et al. (2015, Nature Communications), built on this idea and recorded a similar increase of redox-sensitive metals at the onset of the mid-Pridoli extinction event, coinciding with peak abundances of malformed (teratological) fossil microplankton (acritarchs and chitinozoans). By analogy with metal-induced malformations in modern marine microplankton, teratology might serve as an independent proxy for monitoring changes in the metal concentration of the Palaeozoic ocean. These data from the Ireviken and Pridoli events are the foundation for the hypothesis that many, if not all, of these Late Ordovician-Silurian extinctions are caused by large-scale 'oceanic anoxic events'. Here, we are testing this hypothesis for the most devastating extinction event in this series, the Hirnantian mass extinction. Bulk rock samples spanning the Hirnantian strata of Anticosti Island were geochemically analysed. Our choice of sections is guided by the presence of teratological acritarchs (Delabroye et al., 2012, Rev. Pal. Pal.) that overlap the base of the extinction horizon. Revealing similar results as in our the previous studies, the new XRF data show distinct peaks in redox sensitive metals, supporting ocean anoxia and metal pollution as an important factor in the Hirnantian extinction, if not its fundamental cause.

  11. The Butterflies of Barro Colorado Island, Panama: Local Extinction since the 1930s

    Science.gov (United States)

    Basset, Yves; Barrios, Héctor; Segar, Simon; Srygley, Robert B.; Aiello, Annette; Warren, Andrew D.; Delgado, Francisco; Coronado, James; Lezcano, Jorge; Arizala, Stephany; Rivera, Marleny; Perez, Filonila; Bobadilla, Ricardo; Lopez, Yacksecari; Ramirez, José Alejandro

    2015-01-01

    Few data are available about the regional or local extinction of tropical butterfly species. When confirmed, local extinction was often due to the loss of host-plant species. We used published lists and recent monitoring programs to evaluate changes in butterfly composition on Barro Colorado Island (BCI, Panama) between an old (1923–1943) and a recent (1993–2013) period. Although 601 butterfly species have been recorded from BCI during the 1923–2013 period, we estimate that 390 species are currently breeding on the island, including 34 cryptic species, currently only known by their DNA Barcode Index Number. Twenty-three butterfly species that were considered abundant during the old period could not be collected during the recent period, despite a much higher sampling effort in recent times. We consider these species locally extinct from BCI and they conservatively represent 6% of the estimated local pool of resident species. Extinct species represent distant phylogenetic branches and several families. The butterfly traits most likely to influence the probability of extinction were host growth form, wing size and host specificity, independently of the phylogenetic relationships among butterfly species. On BCI, most likely candidates for extinction were small hesperiids feeding on herbs (35% of extinct species). However, contrary to our working hypothesis, extinction of these species on BCI cannot be attributed to loss of host plants. In most cases these host plants remain extant, but they probably subsist at lower or more fragmented densities. Coupled with low dispersal power, this reduced availability of host plants has probably caused the local extinction of some butterfly species. Many more bird than butterfly species have been lost from BCI recently, confirming that small preserves may be far more effective at conserving invertebrates than vertebrates and, therefore, should not necessarily be neglected from a conservation viewpoint. PMID:26305111

  12. The Butterflies of Barro Colorado Island, Panama: Local Extinction since the 1930s.

    Directory of Open Access Journals (Sweden)

    Yves Basset

    Full Text Available Few data are available about the regional or local extinction of tropical butterfly species. When confirmed, local extinction was often due to the loss of host-plant species. We used published lists and recent monitoring programs to evaluate changes in butterfly composition on Barro Colorado Island (BCI, Panama between an old (1923-1943 and a recent (1993-2013 period. Although 601 butterfly species have been recorded from BCI during the 1923-2013 period, we estimate that 390 species are currently breeding on the island, including 34 cryptic species, currently only known by their DNA Barcode Index Number. Twenty-three butterfly species that were considered abundant during the old period could not be collected during the recent period, despite a much higher sampling effort in recent times. We consider these species locally extinct from BCI and they conservatively represent 6% of the estimated local pool of resident species. Extinct species represent distant phylogenetic branches and several families. The butterfly traits most likely to influence the probability of extinction were host growth form, wing size and host specificity, independently of the phylogenetic relationships among butterfly species. On BCI, most likely candidates for extinction were small hesperiids feeding on herbs (35% of extinct species. However, contrary to our working hypothesis, extinction of these species on BCI cannot be attributed to loss of host plants. In most cases these host plants remain extant, but they probably subsist at lower or more fragmented densities. Coupled with low dispersal power, this reduced availability of host plants has probably caused the local extinction of some butterfly species. Many more bird than butterfly species have been lost from BCI recently, confirming that small preserves may be far more effective at conserving invertebrates than vertebrates and, therefore, should not necessarily be neglected from a conservation viewpoint.

  13. The Butterflies of Barro Colorado Island, Panama: Local Extinction since the 1930s.

    Science.gov (United States)

    Basset, Yves; Barrios, Héctor; Segar, Simon; Srygley, Robert B; Aiello, Annette; Warren, Andrew D; Delgado, Francisco; Coronado, James; Lezcano, Jorge; Arizala, Stephany; Rivera, Marleny; Perez, Filonila; Bobadilla, Ricardo; Lopez, Yacksecari; Ramirez, José Alejandro

    2015-01-01

    Few data are available about the regional or local extinction of tropical butterfly species. When confirmed, local extinction was often due to the loss of host-plant species. We used published lists and recent monitoring programs to evaluate changes in butterfly composition on Barro Colorado Island (BCI, Panama) between an old (1923-1943) and a recent (1993-2013) period. Although 601 butterfly species have been recorded from BCI during the 1923-2013 period, we estimate that 390 species are currently breeding on the island, including 34 cryptic species, currently only known by their DNA Barcode Index Number. Twenty-three butterfly species that were considered abundant during the old period could not be collected during the recent period, despite a much higher sampling effort in recent times. We consider these species locally extinct from BCI and they conservatively represent 6% of the estimated local pool of resident species. Extinct species represent distant phylogenetic branches and several families. The butterfly traits most likely to influence the probability of extinction were host growth form, wing size and host specificity, independently of the phylogenetic relationships among butterfly species. On BCI, most likely candidates for extinction were small hesperiids feeding on herbs (35% of extinct species). However, contrary to our working hypothesis, extinction of these species on BCI cannot be attributed to loss of host plants. In most cases these host plants remain extant, but they probably subsist at lower or more fragmented densities. Coupled with low dispersal power, this reduced availability of host plants has probably caused the local extinction of some butterfly species. Many more bird than butterfly species have been lost from BCI recently, confirming that small preserves may be far more effective at conserving invertebrates than vertebrates and, therefore, should not necessarily be neglected from a conservation viewpoint.

  14. Reconstructing past ecological networks: the reconfiguration of seed-dispersal interactions after megafaunal extinction.

    Science.gov (United States)

    Pires, Mathias M; Galetti, Mauro; Donatti, Camila I; Pizo, Marco A; Dirzo, Rodolfo; Guimarães, Paulo R

    2014-08-01

    The late Quaternary megafaunal extinction impacted ecological communities worldwide, and affected key ecological processes such as seed dispersal. The traits of several species of large-seeded plants are thought to have evolved in response to interactions with extinct megafauna, but how these extinctions affected the organization of interactions in seed-dispersal systems is poorly understood. Here, we combined ecological and paleontological data and network analyses to investigate how the structure of a species-rich seed-dispersal network could have changed from the Pleistocene to the present and examine the possible consequences of such changes. Our results indicate that the seed-dispersal network was organized into modules across the different time periods but has been reconfigured in different ways over time. The episode of megafaunal extinction and the arrival of humans changed how seed dispersers were distributed among network modules. However, the recent introduction of livestock into the seed-dispersal system partially restored the original network organization by strengthening the modular configuration. Moreover, after megafaunal extinctions, introduced species and some smaller native mammals became key components for the structure of the seed-dispersal network. We hypothesize that such changes in network structure affected both animal and plant assemblages, potentially contributing to the shaping of modern ecological communities. The ongoing extinction of key large vertebrates will lead to a variety of context-dependent rearranged ecological networks, most certainly affecting ecological and evolutionary processes.

  15. Inhibiting corticosterone synthesis during fear memory formation exacerbates cued fear extinction memory deficits within the single prolonged stress model.

    Science.gov (United States)

    Keller, Samantha M; Schreiber, William B; Stanfield, Briana R; Knox, Dayan

    2015-01-01

    Using the single prolonged stress (SPS) animal model of post-traumatic stress disorder (PTSD), previous studies suggest that enhanced glucocorticoid receptor (GR) expression leads to cued fear extinction retention deficits. However, it is unknown how the endogenous ligand of GRs, corticosterone (CORT), may contribute to extinction retention deficits in the SPS model. Given that CORT synthesis during fear learning is critical for fear memory consolidation and SPS enhances GR expression, CORT synthesis during fear memory formation could strengthen fear memory in SPS rats by enhancing GR activation during fear learning. In turn, this could lead to cued fear extinction retention deficits. We tested the hypothesis that CORT synthesis during fear learning leads to cued fear extinction retention deficits in SPS rats by administering the CORT synthesis inhibitor metyrapone to SPS and control rats prior to fear conditioning, and observed the effect this had on extinction memory. Inhibiting CORT synthesis during fear memory formation in control rats tended to decrease cued freezing, though this effect never reached statistical significance. Contrary to our hypothesis, inhibiting CORT synthesis during fear memory formation disrupted extinction retention in SPS rats. This finding suggests that even though SPS exposure leads to cued fear extinction memory deficits, CORT synthesis during fear memory formation enhances extinction retention in SPS rats. This suggests that stress-induced CORT synthesis in previously stressed rats can be beneficial.

  16. Compound stimulus presentation and the norepinephrine reuptake inhibitor atomoxetine enhance long-term extinction of cocaine-seeking behavior.

    Science.gov (United States)

    Janak, Patricia H; Bowers, M Scott; Corbit, Laura H

    2012-03-01

    Drug abstinence is frequently compromised when addicted individuals are re-exposed to environmental stimuli previously associated with drug use. Research with human addicts and in animal models has demonstrated that extinction learning (non-reinforced cue-exposure) can reduce the capacity of such stimuli to induce relapse, yet extinction therapies have limited long-term success under real-world conditions (Bouton, 2002; O'Brien, 2008). We hypothesized that enhancing extinction would reduce the later ability of drug-predictive cues to precipitate drug-seeking behavior. We, therefore, tested whether compound stimulus presentation and pharmacological treatments that augment noradrenergic activity (atomoxetine; norepinephrine reuptake inhibitor) during extinction training would facilitate the extinction of drug-seeking behaviors, thus reducing relapse. Rats were trained that the presentation of a discrete cue signaled that a lever press response would result in cocaine reinforcement. Rats were subsequently extinguished and spontaneous recovery of drug-seeking behavior following presentation of previously drug-predictive cues was tested 4 weeks later. We find that compound stimulus presentations or pharmacologically increasing noradrenergic activity during extinction training results in less future recovery of responding, whereas propranolol treatment reduced the benefit seen with compound stimulus presentation. These data may have important implications for understanding the biological basis of extinction learning, as well as for improving the outcome of extinction-based therapies.

  17. Proposal for a Simple and Efficient Monthly Quality Management Program Assessing the Consistency of Robotic Image-Guided Small Animal Radiation Systems.

    Science.gov (United States)

    Brodin, N Patrik; Guha, Chandan; Tomé, Wolfgang A

    2015-11-01

    Modern pre-clinical radiation therapy (RT) research requires high precision and accurate dosimetry to facilitate the translation of research findings into clinical practice. Several systems are available that provide precise delivery and on-board imaging capabilities, highlighting the need for a quality management program (QMP) to ensure consistent and accurate radiation dose delivery. An ongoing, simple, and efficient QMP for image-guided robotic small animal irradiators used in pre-clinical RT research is described. Protocols were developed and implemented to assess the dose output constancy (based on the AAPM TG-61 protocol), cone-beam computed tomography (CBCT) image quality and object representation accuracy (using a custom-designed imaging phantom), CBCT-guided target localization accuracy and consistency of the CBCT-based dose calculation. To facilitate an efficient read-out and limit the user dependence of the QMP data analysis, a semi-automatic image analysis and data representation program was developed using the technical computing software MATLAB. The results of the first 6-mo experience using the suggested QMP for a Small Animal Radiation Research Platform (SARRP) are presented, with data collected on a bi-monthly basis. The dosimetric output constancy was established to be within ±1 %, the consistency of the image resolution was within ±0.2 mm, the accuracy of CBCT-guided target localization was within ±0.5 mm, and dose calculation consistency was within ±2 s (±3%) per treatment beam. Based on these results, this simple quality assurance program allows for the detection of inconsistencies in dosimetric or imaging parameters that are beyond the acceptable variability for a reliable and accurate pre-clinical RT system, on a monthly or bi-monthly basis.

  18. Immediate extinction causes a less durable loss of performance than delayed extinction following either fear or appetitive conditioning

    OpenAIRE

    Woods, Amanda M.; Bouton, Mark E.

    2008-01-01

    Five experiments with rat subjects compared the effects of immediate and delayed extinction on the durability of extinction learning. Three experiments examined extinction of fear conditioning (using the conditioned emotional response method), and two experiments examined extinction of appetitive conditioning (using the food-cup entry method). In all experiments, conditioning and extinction were accomplished in single sessions, and retention testing took place 24 h after extinction. In both f...

  19. [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.

  20. Retention of perceptual generalization of fear extinction.

    Science.gov (United States)

    Pappens, Meike; Schroijen, Mathias; Van den Bergh, Omer; Van Diest, Ilse

    2015-12-01

    Fear reduction obtained during a fear extinction procedure can generalize from the extinction stimulus to other perceptually similar stimuli. Perceptual generalization of fear extinction typically follows a perceptual gradient, with increasing levels of fear reduction the more a stimulus resembles the extinction stimulus. The current study aimed to investigate whether perceptual generalization of fear extinction can be observed also after a retention interval of 24h. Fear was acquired to three geometrical figures of different sizes (CS(+), CS1(+) and CS2(+)) by consistently pairing them with a short-lasting suffocation experience (US). Three other geometrical figures that were never followed by the US served as control stimuli (CS(-), CS1(-), CS2(-)). Next, only the CS(+) was extinguished by presenting it in the absence of the US. One day later, fear responses to all stimuli were assessed without any US-presentation. Outcome measures included startle blink EMG, skin conductance, US expectancy, respiratory rate and tidal volume. On day 2 spontaneous recovery of fear was observed in US expectancy and tidal volume, but not in the other outcomes. Evidence for the retention of fear extinction generalization was present in US expectancy and skin conductance, but a perceptual gradient in the retention of generalized fear extinction could not be observed.

  1. Resistance to extinction and behavioral momentum.

    Science.gov (United States)

    Nevin, John A

    2012-05-01

    In the metaphor of behavioral momentum, reinforcement is assumed to strengthen discriminated operant behavior in the sense of increasing its resistance to disruption, and extinction is viewed as disruption by contingency termination and reinforcer omission. In multiple schedules of intermittent reinforcement, resistance to extinction is an increasing function of reinforcer rate, consistent with a model based on the momentum metaphor. The partial-reinforcement extinction effect, which opposes the effects of reinforcer rate, can be explained by the large disruptive effect of terminating continuous reinforcement despite its strengthening effect during training. Inclusion of a term for the context of reinforcement during training allows the model to account for a wide range of multiple-schedule extinction data and makes contact with other formulations. The relation between resistance to extinction and reinforcer rate on single schedules of intermittent reinforcement is exactly opposite to that for multiple schedules over the same range of reinforcer rates; however, the momentum model can give an account of resistance to extinction in single as well as multiple schedules. An alternative analysis based on the number of reinforcers omitted to an extinction criterion supports the conclusion that response strength is an increasing function of reinforcer rate during training.

  2. Extinction as discrimination: the molar view.

    Science.gov (United States)

    Baum, William M

    2012-05-01

    The traditional molecular view of behavior explains extinction as the dissipation or inhibition of strength, formerly built up by contiguous reinforcement. In obstinate opposition to this explanation was the partial-reinforcement extinction effect: a partially reinforced response extinguishes more slowly than a continuously reinforced response. It suggests instead that extinction is discrimination. Four pigeons were exposed to daily sessions in which a variable period of food delivery, produced by pecking on a variable-interval schedule, was followed by extinction. The rate of food delivery was varied over a wide range across conditions. Varying the amount of food per delivery inversely with rate of delivery kept response rate from varying excessively. The results confirmed and extended the partial-reinforcement effect; persistence of pecking and time to extinction were inversely related to rate of obtaining food. The results support the molar view of extinction, not as loss of strength of a particular discrete response, but as a transition from one allocation of time among activities to another. Although molecular theories dismiss discrimination due to repeated training and extinction as an impurity or complication, repeated cycles of availability and privation are probably typical of the environment in which most vertebrate species evolved.

  3. Can fear extinction be enhanced? A review of pharmacological and behavioral findings.

    Science.gov (United States)

    Fitzgerald, Paul J; Seemann, Jocelyn R; Maren, Stephen

    2014-06-01

    There is considerable interest, from both a basic and clinical standpoint, in gaining a greater understanding of how pharmaceutical or behavioral manipulations alter fear extinction in animals. Not only does fear extinction in rodents model exposure therapy in humans, where the latter is a cornerstone of behavioral intervention for anxiety disorders such as post-traumatic stress disorder and specific phobias, but also understanding more about extinction provides basic information into learning and memory processes and their underlying circuitry. In this paper, we briefly review three principal approaches that have been used to modulate extinction processes in animals and humans: a purely pharmacological approach, the more widespread approach of combining pharmacology with behavior, and a purely behavioral approach. The pharmacological studies comprise modulation by: brain derived neurotrophic factor (BDNF), d-cycloserine, serotonergic and noradrenergic drugs, neuropeptides, endocannabinoids, glucocorticoids, histone deacetylase (HDAC) inhibitors, and others. These studies strongly suggest that extinction can be modulated by drugs, behavioral interventions, or their combination, although not always in a lasting manner. We suggest that pharmacotherapeutic manipulations provide considerable promise for promoting effective and lasting fear reduction in individuals with anxiety disorders. This article is part of a Special Issue entitled 'Memory enhancement'.

  4. Extinction of food-reinforced instrumental behavior in Japanese quail (Coturnix japonica).

    Science.gov (United States)

    Buriticá, Jonathan; Ortega, Leonardo A; Papini, Mauricio R; Gutiérrez, Germán

    2013-02-01

    Japanese quail (Coturnix japonica) were reinforced with food for traversing a runway for either 18 or 36 trials, administered at a rate of 1 trial per day. Then, all animals received 18 extinction trials. The latency to run from the start box to the goal box was the dependent variable. Extinction was significantly slower in animals that had received 50% partial reinforcement during acquisition, whether relative to a group matched in terms of acquisition trials (36 trials, twice the number of reinforced trials) or relative to a group matched in terms of reinforcements (18 trials). The latter group was also matched in terms of the temporal distribution of acquisition trials with the partial reinforcement group, being trained only on days when the partial group was scheduled to receive a reinforced trial. Thus, there was evidence of a spaced-trial partial reinforcement extinction effect. A comparison of groups receiving large versus small reward magnitudes yielded no evidence of the spaced-trial magnitude of reinforcement extinction effect, even though the large-reward group consumed approximately 3 times more food than the small-reward group. Moreover, a comparison of groups that received 36 versus 18 acquisition trials produced no evidence of the spaced-trial overtraining extinction effect, even though acquisition latencies were significantly lower for the group that received 36 acquisition trials. These results are discussed in relation to comparative research on learning phenomena involving incentive downshift manipulations.

  5. The legacy of the Pleistocene megafauna extinctions on nutrient availability in Amazonia

    Science.gov (United States)

    Doughty, Christopher E.; Wolf, Adam; Malhi, Yadvinder

    2013-09-01

    In the late Pleistocene, 97 genera of large animals went extinct, concentrated in the Americas and Australia. These extinctions had significant effects on ecosystem structure, seed dispersal and land surface albedo. However, the impact of this dramatic extinction on ecosystem nutrient biogeochemistry, through the lateral transport of dung and bodies, has never been explored. Here we analyse this process using a novel mathematical framework that analyses this lateral transport as a diffusion-like process, and we demonstrate that large animals play a disproportionately large role in the horizontal transfer of nutrients across landscapes. For example, we estimate that the extinction of the Amazonian megafauna decreased the lateral flux of the limiting nutrient phosphorus by more than 98%, with similar, though less extreme, decreases in all continents outside of Africa. This resulted in strong decreases in phosphorus availability in eastern Amazonia away from fertile floodplains, a decline which may still be ongoing. The current P limitation in the Amazon basin may be partially a relic of an ecosystem without the functional connectivity it once had. We argue that the Pleistocene megafauna extinctions resulted in large and ongoing disruptions to terrestrial biogeochemical cycling at continental scales and increased nutrient heterogeneity globally.

  6. Evaluation of a Communication Skills Training Program for Companion-Animal Veterinarians: A Pilot Study Using RIAS Coding.

    Science.gov (United States)

    McArthur, Michelle; Fitzgerald, Jennifer

    2016-01-01

    Effective veterinarian communication skills training and the related key outcomes provided the impetus for this study. We implemented a pre-experimental pre-test/post-test single-group design with a sample of 13 veterinarians and their 71 clients to evaluate the effects of a 6.5-hour communication skills intervention for veterinarians. Consultations were audiotaped and analyzed with the Roter Interaction Analysis System (RIAS). Clients completed the Consultation and Relational Care Measure, a global satisfaction scale, a Parent Medical Interview Satisfaction Scale, and the Adherence Intent measure. Veterinarians completed a communication confidence measure and a workshop satisfaction scale. Contrary to expectation, neither veterinarian communication skills nor their confidence improved post-training. Despite client satisfaction and perceptions of veterinarians' relational communication skills not increasing, clients nevertheless reported an increased intent to adhere to veterinarian recommendations. This result is important because client adherence is critical to managing and enhancing the health and well-being of animals. The results of the study suggest that while the workshop was highly regarded, either the duration of the training or practice opportunities were insufficient or a booster session was required to increase veterinarian confidence and integration of new skills. Future research should utilize a randomized control study design to investigate the appropriate intervention with which to achieve change in veterinarian communication skills. Such change could translate to more effective interactions in veterinarians' daily lives.

  7. [Evaluation of animal-assisted therapy for the elderly with senile dementia in a day care program].

    Science.gov (United States)

    Kanamori, M; Suzuki, M; Yamamoto, K; Kanda, M; Matsui, Y; Kozima, E; Takeuchi, S; Oshiro, H

    2001-09-01

    We conducted animal-assisted therapy (AAT) for the elderly with senile dementia in a day care center. AAT was performed between July 27 and October 12, 1999 for a total of six biweekly sessions. The AAT group consisted of 7 subjects; 5 with senile dementia of Alzheimer's type (SDAT) and 2 with vascular dementia (VD). The control group was 20 elderly subjects (7 SDAT, 13 VD). The results were as follows: Comparing between MMS scores at the baseline and those three months later, the average score on MMS before AAT (baseline) was 11.43 (+/- 9.00), and that three months later was 12.29 (+/- 9.69). In the AAT group, the average baseline N-ADL score was 28.43 (+/- 14.00) and that after ATT was 29.57 (+/- 14.47). In the AAT group, the average baseline score on Behave-AD was 11.14 (+/- 4.85), and that three months after AAT was 7.29 (+/- 7.11) (p AAT group. Our findings suggested we should use several evaluation methods for evaluation of the changes of patients receiving AAT.

  8. 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.

  9. Interstellar extinction by fractal polycrystalline graphite clusters?

    CERN Document Server

    Andersen, A C; Pustovit, V N; Niklasson, G A

    2001-01-01

    Certain dust particles in space are expected to appear as clusters of individual grains. The morphology of these clusters could be fractal or compact. To determine how these structural features would affect the interpretation of the observed interstellar extinction peak at $\\sim 4.6~\\mu$m, we have calculated the extinction by compact and fractal polycrystalline graphite clusters consisting of touching identical spheres. We compare three general methods for computing the extinction of the clusters, namely, a rigorous solution and two different discrete-dipole approximation methods.

  10. A model for evolution and extinction

    CERN Document Server

    Roberts, B W; Roberts, Bruce W

    1995-01-01

    We present a model for evolution and extinction in large ecosystems. The model incorporates the effects of interactions between species and the influences of abiotic environmental factors. We study the properties of the model by approximate analytic solution and also by numerical simulation, and use it to make predictions about the distribution of extinctions and species lifetimes that we would expect to see in real ecosystems. It should be possible to test these predictions against the fossil record. The model indicates that a possible mechanism for mass extinction is the coincidence of a large coevolutionary avalanche in the ecosystem with a severe environmental disturbance.

  11. Volcanogenic Dark Matter and Mass Extinctions

    CERN Document Server

    Abbas, S; Abbas, Samar; Abbas, Afsar

    1996-01-01

    The passage of the Earth through dense clumps of dark matter, the presence of which are predicted by certain cosmologies, would produce large quantities of heat in the interior of this planet through the capture and subsequent annihilation of dark matter particles. This heat can cause large-scale volcanism which could in turn have caused the extinction of the dinosaurs and other mass extinctions. The periodicity of such volcanic outbursts agrees with the frequency of palaeontological mass extinctions as well as the observed periodicity in the occurrence of the largest flood basalt provinces on the globe.

  12. A mathematical model for Neanderthal extinction

    CERN Document Server

    Flores, J C

    1997-01-01

    A simple mathematical homogeneous model of competition is used to describe Neanderthal extinction in Europe. It considers two interacting species, Neanderthals and Early Modern Men, in the same ecological niche. Using paleontological data we claim that the parameter of similarity, between both species, fluctuates between 0.992 and 0.997. An extension of the model including migration (diffusion) is also discussed nevertheless, extinction of Neanderthal seems unavoidable. Numerical analysis of travelling wave solution (fronts) comfirms the extinction. The wave-front-velocity is estimated from linear analysis and numerical simulations confirm this estimation. We conjecture a mathematical formulation for the principle of exclusion between competitive interacting species (Gause).

  13. Director, Laboratory Animal Care and Use Section

    Data.gov (United States)

    Federal Laboratory Consortium — The NIAMS Laboratory Animal Care and Use Section (LACU) provides support to all NIAMS Intramural Research Program (IRP) Branches and Laboratories using animals. The...

  14. Animal studies of addictive behavior.

    Science.gov (United States)

    Vanderschuren, Louk J M J; Ahmed, Serge H

    2013-04-01

    It is increasingly recognized that studying drug taking in laboratory animals does not equate to studying genuine addiction, characterized by loss of control over drug use. This has inspired recent work aimed at capturing genuine addiction-like behavior in animals. In this work, we summarize empirical evidence for the occurrence of several DSM-IV-like symptoms of addiction in animals after extended drug use. These symptoms include escalation of drug use, neurocognitive deficits, resistance to extinction, increased motivation for drugs, preference for drugs over nondrug rewards, and resistance to punishment. The fact that addiction-like behavior can occur and be studied in animals gives us the exciting opportunity to investigate the neural and genetic background of drug addiction, which we hope will ultimately lead to the development of more effective treatments for this devastating disorder.

  15. Cholinergic neuronal lesions in the medial septum and vertical limb of the diagonal bands of Broca induce contextual fear memory generalization and impair acquisition of fear extinction.

    Science.gov (United States)

    Knox, Dayan; Keller, Samantha M

    2016-06-01

    Previous research has shown that the ventral medial prefrontal cortex (vmPFC) and hippocampus (Hipp) are critical for extinction memory. Basal forebrain (BF) cholinergic input to the vmPFC and Hipp is critical for neural function in these substrates, which suggests BF cholinergic neurons may be critical for extinction memory. In order to test this hypothesis, we applied cholinergic lesions to different regions of the BF and observed the effects these lesions had on extinction memory. Complete BF cholinergic lesions induced contextual fear memory generalization, and this generalized fear was resistant to extinction. Animals with complete BF cholinergic lesions could not acquire cued fear extinction. Restricted cholinergic lesions in the medial septum and vertical diagonal bands of Broca (MS/vDBB) mimicked the effects that BF cholinergic lesions had on contextual fear memory generalization and acquisition of fear extinction. Cholinergic lesions in the horizontal diagonal band of Broca and nucleus basalis (hDBB/NBM) induced a small deficit in extinction of generalized contextual fear memory with no accompanying deficits in cued fear extinction. The results of this study reveal that MS/vDBB cholinergic neurons are critical for inhibition and extinction of generalized contextual fear memory, and via this process, may be critical for acquisition of cued fear extinction. Further studies delineating neural circuits and mechanisms through which MS/vDBB cholinergic neurons facilitate these emotional memory processes are needed. © 2015 Wiley Periodicals, Inc.

  16. Animal Assisted Therapy and the Reading Education Assistance Dogs[RTM] (R.E.A.D.) Program as Perceived by Volunteer R.E.A.D. Facilitators: A National Study

    Science.gov (United States)

    Swift, Catherine Hayes

    2009-01-01

    This study investigated the demographics and perceptions of participants who utilize animals in academic programs, specifically the volunteers who use dogs to work with at-risk children in reading programs. It presented an argument for incorporating research-supported elements of reading tutor skills into the volunteer tutor training for the…

  17. NEW ULTRAVIOLET EXTINCTION CURVES FOR INTERSTELLAR DUST IN M31

    Energy Technology Data Exchange (ETDEWEB)

    Clayton, Geoffrey C. [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803 (United States); Gordon, Karl D.; Bohlin, R. C. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Bianchi, Luciana C. [Department of Physics and Astronomy, The Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218 (United States); Massa, Derck L.; Wolff, Michael J. [Space Science Institute, 4750 Walnut Street, Suite 205, Boulder, CO 80301 (United States); Fitzpatrick, Edward L., E-mail: gclayton@fenway.phys.lsu.edu, E-mail: bohlin@stsci.edu, E-mail: kgordon@stsci.edu, E-mail: bianchi@jhu.edu, E-mail: mjwolff@spacescience.org, E-mail: edward.fitzpatrick@villanova.edu [Department of Astronomy and Astrophysics, Villanova University, 800 Lancaster Avenue, Villanova, PA 19085 (United States)

    2015-12-10

    New low-resolution UV spectra of a sample of reddened OB stars in M31 were obtained with the Hubble Space Telescope/STIS to study the wavelength dependence of interstellar extinction and the nature of the underlying dust grain populations. Extinction curves were constructed for four reddened sightlines in M31 paired with closely matching stellar atmosphere models. The new curves have a much higher signal-to-noise ratio than previous studies. Direct measurements of N(H i) were made using the Lyα absorption lines enabling gas-to-dust ratios to be calculated. The sightlines have a range in galactocentric distance of 5–14 kpc and represent dust from regions of different metallicities and gas-to-dust ratios. The metallicities sampled range from solar to 1.5 solar. The measured curves show similarity to those seen in the Milky Way and the Large Magellanic Cloud. The Maximum Entropy Method was used to investigate the dust composition and size distribution for the sightlines observed in this program, finding that the extinction curves can be produced with the available carbon and silicon abundances if the metallicity is super-solar.

  18. New Ultraviolet Extinction Curves for Interstellar Dust in M31

    CERN Document Server

    Clayton, Geoffrey C; Bianchi, Luciana C; Massa, Derck L; Fitzpatrick, Edward L; Bohlin, R C; Wolff, Michael J

    2015-01-01

    New low-resolution UV spectra of a sample of reddened OB stars in M31 were obtained with HST/STIS to study the wavelength dependence of interstellar extinction and the nature of the underlying dust grain populations. Extinction curves were constructed for four reddened sightlines in M31 paired with closely matching stellar atmosphere models. The new curves have a much higher S/N than previous studies. Direct measurements of N(H I) were made using the Ly$\\alpha$ absorption lines enabling gas-to-dust ratios to be calculated. The sightlines have a range in galactocentric distance of 5 to 14 kpc and represent dust from regions of different metallicities and gas-to-dust ratios. The metallicities sampled range from Solar to 1.5 Solar. The measured curves show similarity to those seen in the Milky Way and the Large Magellanic Cloud. The Maximum Entropy Method was used to investigate the dust composition and size distribution for the sightlines observed in this program finding that the extinction curves can be produc...

  19. Tricyclic antidepressants: effects on extinction and fear learning.

    Science.gov (United States)

    Ellison, G; Handel, J; Rogers, R; Weiss, J

    1975-01-01

    Rats trained to run an alley for a food reward were extinguished following injections of different antidepressants. When retested several days later, the animals extinguished following pretreatment with the NE reuptake blocker protriptyline showed faster running speeds than did the other groups. Other rats given electrical shocks following pretreatment with protriptyline avoided the compartment in which they had been shocked less than did animals shocked following pretreatment with other antidepressants. This implies an interferance with some aspect of the learning or consolidation process which is correlated with the degree of NE reuptake blockage. It is hypothesized that NE terminals are deactivated following frustrative nonreward or punishment by the conversion and reuptake of the released NE to an altered extinction molecule.

  20. 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...

  1. Animal research

    DEFF Research Database (Denmark)

    Olsson, I.A.S.; Sandøe, Peter

    2012-01-01

    This article presents the ethical issues in animal research using a combined approach of ethical theory and analysis of scientific findings with bearing on the ethical analysis. The article opens with a general discussion of the moral acceptability of animal use in research. The use of animals...... in research is analyzed from the viewpoint of three distinct ethical approaches: contractarianism, utilitarianism, and animal rights view. On a contractarian view, research on animals is only an ethical issue to the extent that other humans as parties to the social contract care about how research animals...

  2. Quantifying extinction probabilities from sighting records: inference and uncertainties.

    Directory of Open Access Journals (Sweden)

    Peter Caley

    Full Text Available Methods are needed to estimate the probability that a population is extinct, whether to underpin decisions regarding the continuation of a invasive species eradication program, or to decide whether further searches for a rare and endangered species could be warranted. Current models for inferring extinction probability based on sighting data typically assume a constant or declining sighting rate. We develop methods to analyse these models in a Bayesian framework to estimate detection and survival probabilities of a population conditional on sighting data. We note, however, that the assumption of a constant or declining sighting rate may be hard to justify, especially for incursions of invasive species with potentially positive population growth rates. We therefore explored introducing additional process complexity via density-dependent survival and detection probabilities, with population density no longer constrained to be constant or decreasing. These models were applied to sparse carcass discoveries associated with the recent incursion of the European red fox (Vulpes vulpes into Tasmania, Australia. While a simple model provided apparently precise estimates of parameters and extinction probability, estimates arising from the more complex model were much more uncertain, with the sparse data unable to clearly resolve the underlying population processes. The outcome of this analysis was a much higher possibility of population persistence. We conclude that if it is safe to assume detection and survival parameters are constant, then existing models can be readily applied to sighting data to estimate extinction probability. If not, methods reliant on these simple assumptions are likely overstating their accuracy, and their use to underpin decision-making potentially fraught. Instead, researchers will need to more carefully specify priors about possible population processes.

  3. Reducing hazards for animals from humans

    Directory of Open Access Journals (Sweden)

    Paul-Pierre Pastoret

    2012-06-01

    Full Text Available If animals may be a source of hazards for humans, the reverse is equally true. The main sources of hazards from humans to animals, are the impact of human introduction of transboundary animal diseases, climate change, globalisation, introduction of invasive species and reduction of biodiversity.There is also a trend toward reducing genetic diversity in domestic animals, such as cattle; there are presently around 700 different breeds of cattle many of which at the verge of extinction (less than 100 reproductive females. The impact of humans is also indirect through detrimental effects on the environment. It is therefore urgent to implement the new concept of “one health"....

  4. Epidemic extinction and control in heterogeneous networks

    CERN Document Server

    Hindes, Jason

    2016-01-01

    We consider epidemic extinction in finite networks with broad variation in local connectivity. Generalizing the theory of large fluctuations to random networks with a given degree distribution, we are able to predict the most probable, or optimal, paths to extinction in various configurations, including truncated power-laws. We find that paths for heterogeneous networks follow a limiting form in which infection first decreases in low-degree nodes, which triggers a rapid extinction in high- degree nodes, and finishes with a residual low-degree extinction. The usefulness of the approach is further demonstrated through optimal control strategies that leverage finite-size fluctuations. Interestingly, we find that the optimal control is a mix of treating both high and low-degree nodes based on large-fluctuation theoretical predictions.

  5. Protostars at Low Extinction in Orion A

    CERN Document Server

    Lewis, John Arban

    2016-01-01

    In the list of young stellar objects compiled by Megeath et al. (2012) for the Orion A molecular cloud, only 44 out of 1208 sources found projected onto low extinction (Ak<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 young stellar objects (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 po...

  6. UV extinction properties of carina nebular dust

    Science.gov (United States)

    Massa, Derck

    1993-01-01

    I have performed an analysis of the UV extinction by dust along the line of sight to the young open cluster Tr 16. The observed curves are parameterized in order to extract quantitative information about the structure of the curves. Furthermore, by constructing differential extinction curves, obtained by differencing curves for stars which lie within a few arc seconds of each other on the sky, I was able to obtain a curve which is free of the effects of foreground extinction, and represents the extinction by the dust in the Tr 16 molecular cloud. I then show that this curve is nearly identical to one due to dust in the Orion molecular cloud. This result shows that dust in the Carina arm exhibits the same behavior as that in the local arm.

  7. Possible involvement of serotonin in extinction.

    Science.gov (United States)

    Beninger, R J; Phillips, A G

    1979-01-01

    In Experiment 1, rats were trained to leverpress for continuous reinforcement with food; half were then intubated with the serotonin synthesis inhibitor parachlorophenylalanine (PCPA: 400 mg/kg) and half with water. In extinction the PCPA-treated rats responded at a higher rate. In Experiment 2, rats were trained on a random interval schedule and then assigned to two groups, treated as in Experiment 1, and tested in extinction. There was no significant difference in the resistance to extinction of the two groups. In Experiment 3, the responding of rats trained in a punished stepdown response paradigm and then given an intragastric injection of PCPA took longer to recover than the responding of water-injected controls. These observations suggest that serotonergic neurons might play a role in extinction processes.

  8. Calibrating the end-Permian mass extinction.

    Science.gov (United States)

    Shen, Shu-zhong; Crowley, James L; Wang, Yue; Bowring, Samuel A; Erwin, Douglas H; Sadler, Peter M; Cao, Chang-qun; Rothman, Daniel H; Henderson, Charles M; Ramezani, Jahandar; Zhang, Hua; Shen, Yanan; Wang, Xiang-dong; Wang, Wei; Mu, Lin; Li, Wen-zhong; Tang, Yue-gang; Liu, Xiao-lei; Liu, Lu-jun; Zeng, Yong; Jiang, Yao-fa; Jin, Yu-gan

    2011-12-09

    The end-Permian mass extinction was the most severe biodiversity crisis in Earth history. To better constrain the timing, and ultimately the causes of this event, we collected a suite of geochronologic, isotopic, and biostratigraphic data on several well-preserved sedimentary sections in South China. High-precision U-Pb dating reveals that the extinction peak occurred just before 252.28 ± 0.08 million years ago, after a decline of 2 per mil (‰) in δ(13)C over 90,000 years, and coincided with a δ(13)C excursion of -5‰ that is estimated to have lasted ≤20,000 years. The extinction interval was less than 200,000 years and synchronous in marine and terrestrial realms; associated charcoal-rich and soot-bearing layers indicate widespread wildfires on land. A massive release of thermogenic carbon dioxide and/or methane may have caused the catastrophic extinction.

  9. Periodicity of extinctions in the geologic past.

    Science.gov (United States)

    Raup, D M; Sepkoski, J J

    1984-02-01

    The temporal distribution of the major extinctions over the past 250 million years has been investigated statistically using various forms of time series analysis. The analyzed record is based on variation in extinction intensity for fossil families of marine vertebrates, invertebrates, and protozoans and contains 12 extinction events. The 12 events show a statistically significant periodicity (P less than 0.01) with a mean interval between events of 26 million years. Two of the events coincide with extinctions that have been previously linked to meteorite impacts (terminal Cretaceous and Late Eocene). Although the causes of the periodicity are unknown, it is possible that they are related to extraterrestrial forces (solar, solar system, or galactic).

  10. 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....

  11. Optical atmospheric extinction over Cerro Paranal

    National Research Council Canada - National Science Library

    Patat, F; Moehler, S; O'Brien, K; Pompei, E; Bensby, T; Carraro, G; Ugarte Postigo, de, 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...

  12. Extinction in the Lotka-Volterra model.

    Science.gov (United States)

    Parker, Matthew; Kamenev, Alex

    2009-08-01

    Birth-death processes often exhibit an oscillatory behavior. We investigate a particular case where the oscillation cycles are marginally stable on the mean-field level. An iconic example of such a system is the Lotka-Volterra model of predator-prey interaction. Fluctuation effects due to discreteness of the populations destroy the mean-field stability and eventually drive the system toward extinction of one or both species. We show that the corresponding extinction time scales as a certain power-law of the population sizes. This behavior should be contrasted with the extinction of models stable in the mean-field approximation. In the latter case the extinction time scales exponentially with size.

  13. Biomarker Records Associated with Mass Extinction Events

    Science.gov (United States)

    Whiteside, Jessica H.; Grice, Kliti

    2016-06-01

    The history of life on Earth is punctuated by a series of mass extinction episodes that vary widely in their magnitude, duration, and cause. Biomarkers are a powerful tool for the reconstruction of historical environmental conditions and can therefore provide insights into the cause and responses to ancient extinction events. In examining the five largest mass extinctions in the geological record, investigators have used biomarkers to elucidate key processes such as eutrophy, euxinia, ocean acidification, changes in hydrological balance, and changes in atmospheric CO2. By using these molecular fossils to understand how Earth and its ecosystems have responded to unusual environmental activity during these extinctions, models can be made to predict how Earth will respond to future changes in its climate.

  14. Anthropogenic stressors and riverine fish extinctions

    NARCIS (Netherlands)

    Dias, M.S.; Tedesco, P.A.; Hugueny, B.; Jézéquel, C.; Beauchard, O.; Brosse, S.; Oberdorff, T.

    2017-01-01

    Human activities are often implicated in the contemporary extinction of contemporary species. Concerningriverine fishes, the major biotic and abiotic threats widely cited include introduction of non-nativespecies, habitat fragmentation and homogenization in stream flow dynamics due to the damming

  15. Periaqueductal gray c-Fos expression varies relative to the method of conditioned taste aversion extinction employed.

    Science.gov (United States)

    Mickley, G Andrew; Wilson, Gina N; Remus, Jennifer L; Ramos, Linnet; Ketchesin, Kyle D; Biesan, Orion R; Luchsinger, Joseph R; Prodan, Suzanna

    2011-11-14

    A conditioned taste aversion (CTA) is acquired when an animal consumes a novel taste (CS) and then experiences the symptoms of poisoning (US). Following CTA training, animals will avoid the taste that was previously associated with malaise. This defensive reaction to a learned fear can be extinguished by repeated exposure to the CS alone (CS-only; CSO-EXT). However, following a latency period in which the CS is not presented, the CTA will spontaneously recover (SR). Through the use of an explicitly unpaired extinction procedure (EU-EXT) we have shown that we can speed up extinction and attenuate SR of the CTA. Here we compared and contrasted the ability of CSO and EU extinction procedures to affect c-Fos expression in the periaqueductal gray (PAG). Fluid-deprived Sprague-Dawley rats acquired a strong CTA [via 3 pairings of 0.3% oral saccharin (SAC; the CS) and 81mg/kg i.p. lithium chloride (LiCl; the US)] followed by extinction trials consisting of multiple exposures to either, (a) the CS every-other day (CSO-EXT), or (b) CS and US on alternate days (EU-EXT). A different group of rats did not receive multiple CS exposures and served as a "no extinction" (NE) control. Both extinction procedures resulted in ≥90% reacceptance of SAC (achieving asymptotic extinction). Some of the animals were sacrificed for c-Fos immunohistochemical analysis following asymptotic extinction. Other rats entered a 30-day latency period where they drank water only. These remaining animals were then tested for SR with a final exposure to SAC before being sacrificed for c-Fos immunohistochemistry. As reported previously, rats in the CS-only group exhibited a significant SR of the CTA. However, animals in the EU extinction group reached asymptotic extinction more rapidly than did CSO rats and they did not show SR of the CTA. As compared to rats that retained their CTA, both groups of extinguished rats showed suppression in the number of c-Fos-labeled neurons in all 4 longitudinal columns of

  16. Extinction in the Galaxy from surface brightnesses of ESO-LV galaxies: testing 'standard' extinction maps

    OpenAIRE

    Choloniewski, Jacek; Valentijn, Edwin A.

    2003-01-01

    The relative extinction in the Galaxy computed with our new method (Choloniewski and Valentijn 2003, CV) is compared with three patterns: Schlegel, Finkbeiner and Davis (1998, SFD), Burstein and Heiles (1978, BH) and the cosecans law. It is shown that extinction of SFD is more reliable then that of BH since it stronger correlates with our new extinction. The smallest correlation coeffcient have been obtained for the cosecans law. Linear regression analysis show that SFD overestimate the extin...

  17. An Analysis of the Shapes of Ultraviolet Extinction Curves. IV. Extinction without Standards

    OpenAIRE

    Fitzpatrick, Edward L.; Massa, Derck

    2005-01-01

    We present a new method for deriving UV-through-IR extinction curves, based on the use of stellar atmosphere models to provide estimates of the intrinsic (i.e., unreddened) stellar spectral energy distributions (SEDs), rather than unreddened (or lightly reddened) standard stars. We show that this ``extinction-without-standards'' technique greatly increases the accuracy of the derived extinction curves and allows realistic estimations of the uncertainties. An additional benefit of the techniqu...

  18. 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 and de...... Human newcomers during the last part of the period. The conclusion is that other reasons for extinction than climate or starvation must be sought....

  19. 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.

  20. Extinction rates of established spatial populations

    Science.gov (United States)

    Meerson, Baruch; Sasorov, Pavel V.

    2011-01-01

    This paper deals with extinction of an isolated population caused by intrinsic noise. We model the population dynamics in a “refuge” as a Markov process which involves births and deaths on discrete lattice sites and random migrations between neighboring sites. In extinction scenario I, the zero population size is a repelling fixed point of the on-site deterministic dynamics. In extinction scenario II, the zero population size is an attracting fixed point, corresponding to what is known in ecology as the Allee effect. Assuming a large population size, we develop a WKB (Wentzel-Kramers-Brillouin) approximation to the master equation. The resulting Hamilton’s equations encode the most probable path of the population toward extinction and the mean time to extinction. In the fast-migration limit these equations coincide, up to a canonical transformation, with those obtained, in a different way, by Elgart and Kamenev [Phys. Rev. EPHYADX1539-375510.1103/PhysRevE.70.041106 70, 041106 (2004)]. We classify possible regimes of population extinction with and without an Allee effect and for different types of refuge, and solve several examples analytically and numerically. For a very strong Allee effect, the extinction problem can be mapped into the overdamped limit of the theory of homogeneous nucleation due to Langer [Ann. Phys. (NY)APNYA60003-491610.1016/0003-4916(69)90153-5 54, 258 (1969)]. In this regime, and for very long systems, we predict an optimal refuge size that maximizes the mean time to extinction.

  1. 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 and de...... Human newcomers during the last part of the period. The conclusion is that other reasons for extinction than climate or starvation must be sought....

  2. Animal Bites

    Science.gov (United States)

    ... or territory. Attacks by pets are more common. Animal bites rarely are life-threatening, but if they become infected, you can develop serious medical problems. To prevent animal bites and complications from bites Never pet, handle, ...

  3. Animal Farm

    Institute of Scientific and Technical Information of China (English)

    徐蓉蓉

    2015-01-01

    This essay first introduce the background of Animal Farm and a brief introduction of the author.Then it discuss three thesis about this novel and briefly discussed about it.At last it give highly review on Animal Farm.

  4. 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.

  5. 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

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

    NARCIS (Netherlands)

    A. Nollkaemper

    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

  7. Extinction of conditioned opiate withdrawal in rats is blocked by intracerebroventricular infusion of an NMDA receptor antagonist.

    Science.gov (United States)

    Coleman, Brian R; Carlezon, William A; Myers, Karyn M

    2013-04-29

    Maladaptive conditioned responses (CRs) contribute to psychiatric disorders including anxiety disorders and addiction. Methods of reducing these CRs have been considered as possible therapeutic approaches. One such method is extinction, which involves exposure to CR-eliciting cues in the absence of the event they once predicted. In animal models, extinction reduces both fear and addiction-related CRs, and in humans, extinction-based cue exposure therapy (CET) reduces fear CRs. However, CET is less effective in drug addicts, for reasons that are not clear. Increased understanding of the neurobiology of extinction of drug-related CRs as compared to fear CRs may help illuminate this issue. Here, we examine the N-methyl-d-aspartate (NMDA) receptor-dependence of extinction of conditioned opiate withdrawal in rats. Using a place conditioning paradigm, we trained morphine-dependent rats to associate an environment with naloxone-precipitated withdrawal. We then extinguished that association by returning the rats repeatedly to the environment in the absence of acute withdrawal. In some rats we administered the NMDA receptor antagonist d,l-2-amino-5-phosphovaleric acid (AP5) intracerebroventricularly immediately prior to extinction training. In a subsequent test session, these rats avoided the formerly naloxone-paired environment, similar to rats that had not undergone extinction training. By contrast, rats that received vehicle prior to extinction training did not avoid the formerly naloxone-paired environment. This finding indicates that extinction of a drug-related CR (conditioned opiate withdrawal) is dependent on NMDA receptors, similar to extinction of conditioned fear. The locus of the critical NMDA receptors is unclear but may include basolateral amygdala and/or medial prefrontal cortex.

  8. Animal models

    DEFF Research Database (Denmark)

    Gøtze, Jens Peter; Krentz, Andrew

    2014-01-01

    In this issue of Cardiovascular Endocrinology, we are proud to present a broad and dedicated spectrum of reviews on animal models in cardiovascular disease. The reviews cover most aspects of animal models in science from basic differences and similarities between small animals and the human...

  9. Animal Deliberation

    NARCIS (Netherlands)

    Driessen, C.P.G.

    2014-01-01

    While much has been written on environmental politics on the one hand, and animal ethics and welfare on the other, animal politics, as the interface of the two, is underexamined. There are key political implications in the increase of animal protection laws, the rights of nature, and political parti

  10. The role of medial prefrontal cortex in extinction and reinstatement of alcohol-seeking in rats.

    Science.gov (United States)

    Willcocks, Andrea L; McNally, Gavan P

    2013-01-01

    The prelimbic (PL) and infralimbic (IL) medial prefrontal cortex (mPFC) are thought to play opposing roles in drug-seeking behaviour. Specifically, the PL promotes drug-seeking whereas the IL is necessary for the inhibition of drug-seeking during extinction. We studied the roles of the PL, IL and dorsal peduncular PFC (DP) in the expression of context-induced reinstatement, reacquisition and extinction of alcoholic beer-seeking. In context-induced reinstatement (renewal), animals were trained to nosepoke for alcoholic beer (context A), extinguished (context B) and then tested in context A and B. In reacquisition, animals received the same instrumental training and extinction without any contextual manipulation. On test, alcoholic beer was again available and responding was compared with naive controls. Just prior to the test, rats received bilateral infusion of baclofen/muscimol into the PL, IL or DP. Reversible inactivation of the PL attenuated ABA renewal but augmented reacquisition. Reversible inactivation of IL had no effect on the reinstatement or reacquisition of alcoholic beer-seeking and had no effect on extinction expression (ABB and AAA). IL inactivation did, however, increase the latencies with which animals responded on test but only when animals were tested in the extinction context. DP inactivation had no effect on reinstatement or reacquisition. These studies are inconsistent with the view that PL and IL exert opposing effects on drug-seeking. Rather, they support the view that PL is important for retrieval of drug-seeking contingency information and that the use of contextual information is enhanced with IL manipulation.

  11. 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.

  12. Immediate Extinction Causes a Less Durable Loss of Performance than Delayed Extinction following Either Fear or Appetitive Conditioning

    Science.gov (United States)

    Woods, Amanda M.; Bouton, Mark E.

    2008-01-01

    Five experiments with rat subjects compared the effects of immediate and delayed extinction on the durability of extinction learning. Three experiments examined extinction of fear conditioning (using the conditioned emotional response method), and two experiments examined extinction of appetitive conditioning (using the food-cup entry method). In…

  13. Trophically Unique Species Are Vulnerable to Cascading Extinction

    OpenAIRE

    Petchey, Owen L.; Eklöf, Anna; Borrvall, Charlotte; Ebenman, Bo

    2008-01-01

    Understanding which species might become extinct and the consequences of such loss is critical. One consequence is a cascade of further, secondary extinctions. While a significant amount is known about the types of communities and species that suffer secondary extinctions, little is known about the consequences of secondary extinctions for biodiversity. Here we examine the effect of these secondary extinctions on trophic diversity, the range of trophic roles played by the species in a communi...

  14. Entry, Descent, Landing Animation (Animation)

    Science.gov (United States)

    2005-01-01

    [figure removed for brevity, see original site] Click on the image for Entry, Descent, Landing animation This animation illustrates the path the Stardust return capsule will follow once it enters Earth's atmosphere.

  15. Entry, Descent, Landing Animation (Animation)

    Science.gov (United States)

    2005-01-01

    [figure removed for brevity, see original site] Click on the image for Entry, Descent, Landing animation This animation illustrates the path the Stardust return capsule will follow once it enters Earth's atmosphere.

  16. Fear erasure in mice requires synergy between antidepressant drugs and extinction training.

    Science.gov (United States)

    Karpova, Nina N; Pickenhagen, Anouchka; Lindholm, Jesse; Tiraboschi, Ettore; Kulesskaya, Natalia; Agústsdóttir, Arna; Antila, Hanna; Popova, Dina; Akamine, Yumiko; Bahi, Amine; Sullivan, Regina; Hen, René; Drew, Liam J; Castrén, Eero

    2011-12-23

    Antidepressant drugs and psychotherapy combined are more effective in treating mood disorders than either treatment alone, but the neurobiological basis of this interaction is unknown. To investigate how antidepressants influence the response of mood-related systems to behavioral experience, we used a fear-conditioning and extinction paradigm in mice. Combining extinction training with chronic fluoxetine, but neither treatment alone, induced an enduring loss of conditioned fear memory in adult animals. Fluoxetine treatment increased synaptic plasticity, converted the fear memory circuitry to a more immature state, and acted through local brain-derived neurotrophic factor. Fluoxetine-induced plasticity may allow fear erasure by extinction-guided remodeling of the memory circuitry. Thus, the pharmacological effects of antidepressants need to be combined with psychological rehabilitation to reorganize networks rendered more plastic by the drug treatment.

  17. Elevational distribution and extinction risk in birds.

    Directory of Open Access Journals (Sweden)

    Rachel L White

    Full Text Available Mountainous regions are hotspots of terrestrial biodiversity. Unlike islands, which have been the focus of extensive research on extinction dynamics, fewer studies have examined mountain ranges even though they face increasing threats from human pressures - notably habitat conversion and climate change. Limits to the taxonomic and geographical extent and resolution of previously available information have precluded an explicit assessment of the relative role of elevational distribution in determining extinction risk. We use a new global species-level avian database to quantify the influence of elevational distribution (range, maximum and midpoint on extinction risk in birds at the global scale. We also tested this relationship within biogeographic realms, higher taxonomic levels, and across phylogenetic contrasts. Potential confounding variables (i.e. phylogenetic, distributional, morphological, life history and niche breadth were also tested and controlled for. We show that the three measures of elevational distribution are strong negative predictors of avian extinction risk, with elevational range comparable and complementary to that of geographical range size. Extinction risk was also found to be positively associated with body weight, development and adult survival, but negatively associated with reproduction and niche breadth. The robust and consistent findings from this study demonstrate the importance of elevational distribution as a key driver of variation in extinction dynamics in birds. Our results also highlight elevational distribution as a missing criterion in current schemes for quantifying extinction risk and setting species conservation priorities in birds. Further research is recommended to test for generality across non-avian taxa, which will require an advance in our knowledge of species' current elevational ranges and increased efforts to digitise and centralise such data.

  18. Reducing spontaneous recovery and reinstatement of operant performance through extinction-cues.

    Science.gov (United States)

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

    2017-02-01

    It has been argued that the response recovery effects share a common mechanism. A possible way to test it is evaluating whether the techniques that impaired renewal would impair the other recovery effects as well. Two experiments with rats used a free operant procedure to explore whether an extinction-cue could prevent the spontaneous recovery and reinstatement of an extinguished lever-pressing. Both experiments consisted of four phases: Acquisition, Extinction and Test 1 and Test 2. First, all rats were trained to perform one instrumental response (R1) for food in context A, and a different instrumental response (R2) for food in context B. Then, responses were extinguished within the same context: R1 in context A and R2 in context B. Throughout this phase all rats received brief presentations of a tone (extinction-cue). In both experiments animals were tested twice. The first test was conducted immediately after the last extinction session. In this test, rats received the extinction-cue for both responses. During the second test, rats experienced the tone only for R1. In Experiment 1 rats were tested after 5days, while for Experiment 2 test 2 took place after a single session of re-exposure to the food. Both experiments showed a recovery effect (spontaneous recovery in Experiment 1 and reinstatement in Experiment 2) for both responses. However, a cue featured in extinction attenuated recovery of R1 in both experiments when presented on the test. The findings suggest that spontaneous recovery, reinstatement and renewal might share a common mechanism. In addition, the present data shows that using an extinction-cue could help to reduces relapsing of voluntary behaviors.

  19. Climate warming and humans played different roles in triggering Late Quaternary extinctions in east and west Eurasia.

    Science.gov (United States)

    Wan, Xinru; Zhang, Zhibin

    2017-03-29

    Climate change and humans are proposed as the two key drivers of total extinction of many large mammals in the Late Pleistocene and Early Holocene, but disentangling their relative roles remains challenging owing to a lack of quantitative evaluation of human impact and climate-driven distribution changes on the extinctions of these large mammals in a continuous temporal-spatial dimension. Here, our analyses showed that temperature change had significant effects on mammoth (genus Mammuthus), rhinoceros (Rhinocerotidae), horse (Equidae) and deer (Cervidae). Rapid global warming was the predominant factor driving the total extinction of mammoths and rhinos in frigid zones from the Late Pleistocene and Early Holocene. Humans showed significant, negative effects on extirpations of the four mammalian taxa, and were the predominant factor causing the extinction or major extirpations of rhinos and horses. Deer survived both rapid climate warming and extensive human impacts. Our study indicates that both the current rates of warming and range shifts of species are much faster than those from the Late Pleistocene to Holocene. Our results provide new insight into the extinction of Late Quaternary megafauna by demonstrating taxon-, period- and region-specific differences in extinction drivers of climate change and human disturbances, and some implications about the extinction risk of animals by recent and ongoing climate warming.

  20. Conservation Implications of the Prevalence and Representation of Locally Extinct Mammals in the Folklore of Native Americans

    Directory of Open Access Journals (Sweden)

    Preston Matthew

    2009-01-01

    Full Text Available Many rationales for wildlife conservation have been suggested. One rationale not often mentioned is the impact of extinctions on the traditions of local people, and conservationists′ subsequent need to strongly consider culturally based reasons for conservation. As a first step in strengthening the case for this rationale, we quantitatively examined the presence and representation of eight potentially extinct mammals in folklore of 48 Native American tribes that live/lived near to 11 national parks in the United States. We aimed to confirm if these extinct animals were traditionally important species for Native Americans. At least one-third of the tribes included the extinct mammals in their folklore (N=45 of 124 and about half of these accounts featured the extinct species with positive and respectful attitudes, especially the carnivores. This research has shown that mammals that might have gone locally extinct have been prevalent and important in Native American traditions. Research is now needed to investigate if there indeed has been or might be any effects on traditions due to these extinctions. Regardless, due to even the possibility that the traditions of local people might be adversely affected by the loss of species, conservationists might need to consider not only all the biological reasons to conserve, but also cultural ones.

  1. Modulation of fear extinction by stress, stress hormones and estradiol: a review

    Directory of Open Access Journals (Sweden)

    Ursula eStockhorst

    2016-01-01

    Full Text Available Fear acquisition and extinction are valid models for the etiology and treatment of anxiety, trauma- and stressor-related disorders. These disorders are assumed to involve aversive learning under acute and/or chronic stress. Importantly, fear conditioning and stress share common neuronal circuits. The stress response involves multiple changes interacting in a time-dependent manner: (a the fast first-wave stress response (with central actions of noradrenaline, dopamine, serotonin, corticotropin-releasing hormone, plus increased sympathetic tone and peripheral catecholamine release and (b the second-wave stress response (with peripheral release of glucocorticoids after activation of the hypothalamus-pituitary-adrenocortical axis. Control of fear during extinction is also sensitive to these stress-response mediators. In the present review, we will thus examine current animal and human data, addressing the role of stress and single stress-response mediators for successful acquisition, consolidation and recall of fear extinction. We report studies using pharmacological manipulations targeting a number of stress-related neurotransmitters and neuromodulators (monoamines, opioids, endocannabinoids, neuropeptide Y, oxytocin, glucocorticoids and behavioral stress induction. As anxiety, trauma- and stressor-related disorders are more common in women, recent research focuses on female sex hormones and identifies a potential role for estradiol in fear extinction. We will thus summarize animal and human data on the role of estradiol and explore possible interactions with stress or stress-response mediators in extinction. This also aims at identifying time-windows of enhanced (or reduced sensitivity for fear extinction, and thus also for successful exposure therapy.

  2. Modulation of Fear Extinction by Stress, Stress Hormones and Estradiol: A Review

    Science.gov (United States)

    Stockhorst, Ursula; Antov, Martin I.

    2016-01-01

    Fear acquisition and extinction are valid models for the etiology and treatment of anxiety, trauma- and stressor-related disorders. These disorders are assumed to involve aversive learning under acute and/or chronic stress. Importantly, fear conditioning and stress share common neuronal circuits. The stress response involves multiple changes interacting in a time-dependent manner: (a) the fast first-wave stress response [with central actions of noradrenaline, dopamine, serotonin, corticotropin-releasing hormone (CRH), plus increased sympathetic tone and peripheral catecholamine release] and (b) the second-wave stress response [with peripheral release of glucocorticoids (GCs) after activation of the hypothalamus-pituitary-adrenocortical (HPA) axis]. Control of fear during extinction is also sensitive to these stress-response mediators. In the present review, we will thus examine current animal and human data, addressing the role of stress and single stress-response mediators for successful acquisition, consolidation and recall of fear extinction. We report studies using pharmacological manipulations targeting a number of stress-related neurotransmitters and neuromodulators [monoamines, opioids, endocannabinoids (eCBs), neuropeptide Y, oxytocin, GCs] and behavioral stress induction. As anxiety, trauma- and stressor-related disorders are more common in women, recent research focuses on female sex hormones and identifies a potential role for estradiol in fear extinction. We will thus summarize animal and human data on the role of estradiol and explore possible interactions with stress or stress-response mediators in extinction. This also aims at identifying time-windows of enhanced (or reduced) sensitivity for fear extinction, and thus also for successful exposure therapy. PMID:26858616

  3. Predicting impaired extinction of traumatic memory and elevated startle.

    Directory of Open Access Journals (Sweden)

    Rebecca Nalloor

    Full Text Available BACKGROUND: Emotionally traumatic experiences can lead to debilitating anxiety disorders, such as phobias and Post-Traumatic Stress Disorder (PTSD. Exposure to such experiences, however, is not sufficient to induce pathology, as only up to one quarter of people exposed to such events develop PTSD. These statistics, combined with findings that smaller hippocampal size prior to the trauma is associated with higher risk of developing PTSD, suggest that there are pre-disposing factors for such pathology. Because prospective studies in humans are limited and costly, investigating such pre-dispositions, and thus advancing understanding of the genesis of such pathologies, requires the use of animal models where predispositions are identified before the emotional trauma. Most existing animal models are retrospective: they classify subjects as those with or without a PTSD-like phenotype long after experiencing a traumatic event. Attempts to create prospective animal models have been largely unsuccessful. METHODOLOGY/PRINCIPAL FINDINGS: Here we report that individual predispositions to a PTSD-like phenotype, consisting of impaired rate and magnitude of extinction of an emotionally traumatic event coupled with long-lasting elevation of acoustic startle responses, can be revealed following exposure to a mild stressor, but before experiencing emotional trauma. We compare, in rats, the utility of several classification criteria and report that a combination of criteria based on acoustic startle responses and behavior in an anxiogenic environment is a reliable predictor of a PTSD-like phenotype. CONCLUSIONS/SIGNIFICANCE: There are individual predispositions to developing impaired extinction and elevated acoustic startle that can be identified after exposure to a mildly stressful event, which by itself does not induce such a behavioral phenotype. The model presented here is a valuable tool for studying the etiology and pathophysiology of anxiety disorders and

  4. Auditory peripersonal space in humans: a case of auditory-tactile extinction.

    Science.gov (United States)

    Làdavas, E; Pavani, F; Farnè, A

    2001-01-01

    Animal experiments have shown that the spatial correspondence between auditory and tactile receptive fields of ventral pre-motor neurons provides a map of auditory peripersonal space around the head. This allows neurons to localize a near sound with respect to the head. In the present study, we demonstrated the existence of an auditory peripersonal space around the head in humans. In a right-brain damaged patient with tactile extinction, a sound delivered near the ipsilesional side of the head extinguished a tactile stimulus delivered to the contralesional side of the head (cross-modal auditory-tactile extinction). In contrast, when an auditory stimulus was presented far from the head, cross-modal extinction was dramatically reduced. This spatially specific cross-modal extinction was found only when a complex sound like a white noise burst was presented; pure tones did not produce spatially specific cross-modal extinction. These results show a high degree of functional similarity between the characteristics of the auditory peripersonal space representation in humans and monkeys. This similarity suggests that analogous physiological substrates might be responsible for coding this multisensory integrated representation of peripersonal space in human and non-human primates.

  5. An argument supporting de-extinction and a call for field research

    Directory of Open Access Journals (Sweden)

    Charli N. Davis

    2016-10-01

    Full Text Available With recent advances in biotechnology, the resurrection of recently extinct species has become a possibility, provoking a debate about the wisdom of what has become known as de-extinction. Regardless of the current feasibility and ethical controversies over de-extinction, ongoing technological advancement is likely to result in resurrected species in the near future. In our opinion, de-extinction will be followed by proposals for reintroduction into the wild. We argue that this development could be valuable for the advancement of ecological understanding and conservation.  However, the current conversations are happening in a vacuum. We therefore call for the initiation of field experiments using physiological and ecological surrogates. This type of research could shed light on the potential impacts of resurrected animals on modern ecosystems. While this research would have challenges, it could provide valuable information on th ecology of the past and better prepare scientists and wildlife managers for de-extinction.

  6. Extinction chronology of the woolly rhinoceros Coelodonta antiquitatis in the context of late Quaternary megafaunal extinctions in northern Eurasia

    Science.gov (United States)

    Stuart, Anthony J.; Lister, Adrian M.

    2012-09-01

    Megafaunal extinctions in northern Eurasia (excluding Mediterranean islands) since the Last Interglacial claimed about 37% of species with body weights >44 kg. Here we review the dating evidence for the timings of these extinctions, which were staggered over tens of millennia. Moreover, individual species disappeared at different times in different geographical areas. For example, cave bear probably disappeared ca. 30.5-28.5 ka, at approximately the onset of GS-3 (beginning of 'LGM'), whereas cave lion survived until the Lateglacial ca 14 ka. Others survived into the Holocene: woolly mammoth until ca 10.7 ka in the New Siberian Islands and ca 4 ka on Wrangel Island, giant deer to at least 7.7 ka in western Siberia and European Russia. It is evident that climatic and vegetational changes had major impacts on species' ranges, and moreover the contrasting chronologies and geographical range contractions are consistent with environmental drivers relating to their differing ecologies. However, the possible role of humans in this process has still to be satisfactorily explored. We present a detailed review of the radiocarbon record and extinction chronology of an exclusively northern Eurasian species, the woolly rhinoceros Coelodonta antiquitatis, an animal adapted to feeding on low-growing herbaceous vegetation and a dry climate with minimal snowfall. During the Last Glacial the overall (time-averaged) range of C. antiquitatis extended across most of northern Eurasia, but the species failed to reach North America. On the basis of 233 ultrafiltered AMS radiocarbon dates, together with 50 others which pass our auditing criteria, we reconstruct a detailed chronology for this species. C. antiquitatis was widespread over most of the time span covered by radiocarbon dating, but from ca 35 ka (calibrated) it apparently contracted towards the east, culminating in its probable extinction ca 14 ka, with the latest dates from north-eastern Siberia. It disappeared from Britain, at

  7. 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.

  8. 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.

  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. Determining the extragalactic extinction law with SALT

    CERN Document Server

    Finkelman, Ido; Kniazev, Alexei Y; Buckley, David; O'Donoghue, Darragh; Hashimoto, Yas; Loaring, Nicola; Romero, Encarni; Still, Martin; Vaisanen, Petri

    2008-01-01

    We present CCD imaging observations of early-type galaxies with dark lanes obtained with the Southern African Large Telescope (SALT) during its performance-verification phase. We derive the extinction law by the extragalactic dust in the dark lanes in the spectral range 1.11mu m^{-1} < lambda^{-1} < 2.94 mu m^{-1} by fitting model galaxies to the unextinguished parts of the image, and subtracting from these the actual images. We find that the extinction curves run parallel to the Galactic extinction curve, which implies that the properties of dust in the extragalactic enviroment are similar to those of the Milky Way. The ratio of the total V band extinction to the selective extinction between the V and B bands is derived for each galaxy with an average of 2.82+-0.38, compared to a canonical value of 3.1 for the Milky Way. The similar values imply that galaxies with well-defined dark lanes have characteristic dust grain sizes similar to those of Galactic dust.

  11. 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.

  12. 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.

  13. The transition from memory retrieval to extinction

    Directory of Open Access Journals (Sweden)

    Cammarota Martín

    2004-01-01

    Full Text Available Memory is measured by measuring retrieval. Retrieval is often triggered by the conditioned stimulus (CS; however, as known since Pavlov, presentation of the CS alone generates extinction. One-trial avoidance (IA is a much used conditioned fear paradigm in which the CS is the safe part of a training apparatus, the unconditioned stimulus (US is a footshock and the conditioned response is to stay in the safe area. In IA, retrieval is measured without the US, as latency to step-down from the safe area (i.e., a platform. Extinction is installed at the moment of the first unreinforced test session, as clearly shown by the fact that many drugs, including PKA, ERK and protein synthesis inhibitors as well as NMDA receptor antagonists, hinder extinction when infused into the hippocampus or the basolateral amygdala at the moment of the first test session but not later. Some, but not all the molecular systems required for extinction are also activated by retrieval, further endorsing the hypothesis that although retrieval is behaviorally and biochemically necessary for the generation of extinction, this last process constitutes a new learning secondary to the unreinforced expression of the original trace.

  14. Pedigree and herd characterization of a donkey breed vulnerable to extinction.

    Science.gov (United States)

    Quaresma, M; Martins, A M F; Rodrigues, J B; Colaço, J; Payan-Carreira, R

    2014-03-01

    Most donkey and local horse breeds are vulnerable to extinction as mechanization of agriculture progress throughout the world. The present study analyzed the pedigree and herd records of the donkey Asinina de Miranda breed (RAM), identifying genealogical and human factors that may affect the breed genetic diversity in the future and suggesting suitable strategies to breed preservation, early on the conservation program. The breeding rate was very low, with a ratio of foaling/live animals of 0.23 (178/760). The estimated number of founders and ancestors contributing to the reference population was 128 and 121. The number of founder herds in the reference population was 64, with an effective number of founder herds for the reference population of 7.6. The mean age of herd owners was 65.50 ± 0.884 years, with a negative association among the herd size and owner's age (P<0.001). In contrast, the size of the herd and the ownership of a male were both positively associated (P<0.001) with the herd number of in-born foals. Both the owners' age and the herd location (RAM home region v. dispersal region) were negatively associated with the foaling number (P<0.001). The main identified risk factors were: low breeding rates; low number of males and their unequal contribution to the genetic pool; unequal contribution of the herds to genetic pool; and advanced age of herd owners.

  15. Animal Shelter

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Beijing activist Zhang Luping gives up a lucrative business career to provide a home for stray and abandoned pets "I have never been married, but I have I hundreds of children," said Zhang Luping, founder of the Beijing Human and Animal Environment Education Center (the Animal Center). "God sent me to this planet and gave me the mission of taking care of helpless and homeless dogs and cats. I will never let Him down." The Animal Center, one of a few non-

  16. Animal ethics

    DEFF Research Database (Denmark)

    Palmer, Clare; Sandøe, Peter

    2011-01-01

    This chapter describes and discusses different views concerning our duties towards animals. First, we explain why it is necessary to engage in thinking about animal ethics and why it is not enough to rely on feelings alone. Secondly, we present and discuss five different kinds of views about...... the nature of our duties to animals. They are: contractarianism, utilitarianism, the animal rights view, contextual views, and a respect for nature view. Finally, we briefly consider whether it is possible to combine elements from the presented views, and how to make up one’s mind....

  17. Animated Asphalt

    DEFF Research Database (Denmark)

    Paldam, Camilla Skovbjerg

    2015-01-01

    “animation”, defined as “an innate (and learnable) ability of our bodies to discover life in inanimate images” (Belting 2012, 188). In this essay I investigate the animation of pictures in dialogue with Mitchell, both by addressing general questions such as: how is animation of otherwise static pictures...... to be understood? How does animation differ in different media? And in particular by focusing on and questioning the gender positions inherent in Mitchell’s theory. Animation has an erotic component of seduction and desire, and what pictures want, becomes for Mitchell, what women want. There is of course no simple...

  18. Implications of lemuriform extinctions for the Malagasy flora.

    Science.gov (United States)

    Federman, Sarah; Dornburg, Alex; Daly, Douglas C; Downie, Alexander; Perry, George H; Yoder, Anne D; Sargis, Eric J; Richard, Alison F; Donoghue, Michael J; Baden, Andrea L

    2016-05-01

    Madagascar's lemurs display a diverse array of feeding strategies with complex relationships to seed dispersal mechanisms in Malagasy plants. Although these relationships have been explored previously on a case-by-case basis, we present here the first comprehensive analysis of lemuriform feeding, to our knowledge, and its hypothesized effects on seed dispersal and the long-term survival of Malagasy plant lineages. We used a molecular phylogenetic framework to examine the mode and tempo of diet evolution, and to quantify the associated morphological space occupied by Madagascar's lemurs, both extinct and extant. Using statistical models and morphometric analyses, we demonstrate that the extinction of large-bodied lemurs resulted in a significant reduction in functional morphological space associated with seed dispersal ability. These reductions carry potentially far-reaching consequences for Malagasy ecosystems, and we highlight large-seeded Malagasy plants that appear to be without extant animal dispersers. We also identify living lemurs that are endangered yet occupy unique and essential dispersal niches defined by our morphometric analyses.

  19. Were Malagasy Uncarina fruits dispersed by the extinct elephant bird?

    Directory of Open Access Journals (Sweden)

    N. Illing

    2010-02-01

    Full Text Available We hypothesise that the spiny fruits of the endemic Madagascar
    genus Uncarina (Pedaliaceae are trample burrs that evolved to be
    dispersed on the feet of the extinct elephant bird (Aepyornis. Our
    evidence is: i the morphology of the fruit with its large grapple
    hooks is more likely to attach to a foot than to adhere to fur and
    ii the presentation of mature fruits on the ground rather than in the
    canopy. These differences to adhesive burrs make lemurs unlikely
    dispersers. We argue, given the absence of other large terrestrial
    mammals in Madagascar, that the most likely dispersers of
    Uncarina fruits were the extinct large birds. If correct, our hypothesis
    has implications for conservation of Uncarina, the biogeography
    of the elephant birds and dispersal biology. For
    example, we predict that the demography of Uncarina will be
    skewed towards adult plants, and that the dispersal mutualism
    could possibly be rescued by domestic animals.

  20. Molecular mechanisms of D-cycloserine in facilitating fear extinction: insights from RNAseq.

    Science.gov (United States)

    Malan-Müller, Stefanie; Fairbairn, Lorren; Daniels, Willie M U; Dashti, Mahjoubeh Jalali Sefid; Oakeley, Edward J; Altorfer, Marc; Kidd, Martin; Seedat, Soraya; Gamieldien, Junaid; Hemmings, Sîan Megan Joanna

    2016-02-01

    D-cycloserine (DCS) has been shown to be effective in facilitating fear extinction in animal and human studies, however the precise mechanisms whereby the co-administration of DCS and behavioural fear extinction reduce fear are still unclear. This study investigated the molecular mechanisms of intrahippocampally administered D-cycloserine in facilitating fear extinction in a contextual fear conditioning animal model. Male Sprague Dawley rats (n = 120) were grouped into four experimental groups (n = 30) based on fear conditioning and intrahippocampal administration of either DCS or saline. The light/dark avoidance test was used to differentiate maladapted (MA) (anxious) from well-adapted (WA) (not anxious) subgroups. RNA extracted from the left dorsal hippocampus was used for RNA sequencing and gene expression data was compared between six fear-conditioned + saline MA (FEAR + SALINE MA) and six fear-conditioned + DCS WA (FEAR + DCS WA) animals. Of the 424 significantly downregulated and 25 significantly upregulated genes identified in the FEAR + DCS WA group compared to the FEAR + SALINE MA group, 121 downregulated and nine upregulated genes were predicted to be relevant to fear conditioning and anxiety and stress-related disorders. The majority of downregulated genes transcribed immune, proinflammatory and oxidative stress systems molecules. These molecules mediate neuroinflammation and cause neuronal damage. DCS also regulated genes involved in learning and memory processes, and genes associated with anxiety, stress-related disorders and co-occurring diseases (e.g., cardiovascular diseases, digestive system diseases and nervous system diseases). Identifying the molecular underpinnings of DCS-mediated fear extinction brings us closer to understanding the process of fear extinction.

  1. D-cycloserine effects on extinction of conditioned responses to drug-related cues.

    Science.gov (United States)

    Myers, Karyn M; Carlezon, William A

    2012-06-01

    D-cycloserine (DCS) is an N-methyl-D-aspartate (NMDA) receptor partial agonist that facilitates extinction of conditioned fear in animals and cue exposure therapy (CET) for fear and anxiety disorders in people. Recent preclinical and clinical studies have examined the effect of DCS on extinction of conditioned responses elicited by cues paired with administration of or withdrawal from drugs of abuse, including physiological responses, craving, withdrawal, and drug-seeking behavior. DCS facilitates extinction and blunts postextinction recovery of these responses in animal models, including place conditioning and drug self-administration, but DCS effects on CET in substance users/abusers are less robust. Some of the null effects in the clinical literature might be attributable to issues related to sample size, data characteristics, DCS administration, and participant characteristics, among others. In this review we describe the preclinical and clinical literatures on DCS modulation of extinction of addiction-related conditioned responses, consider possible limitations of the clinical studies that have been published to date, and propose ways of designing future clinical studies so as to maximize the probability of detecting a DCS effect. We also discuss concerns with regard to potential harmful effects of DCS-coupled CET in addicts and describe how these concerns might be mitigated. We conclude that it is as yet unclear whether DCS-coupled CET might be a useful approach in the treatment of addiction.

  2. 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, ...

  3. Life extinctions by neutron star mergers

    CERN Document Server

    Dar, Arnon; Shaviv, N J; Dar, Arnon; Laor, Ari; Shaviv, Nir J.

    1997-01-01

    High energy cosmic ray jets from nearby mergers or accretion induced collapse (AIC) of neutron stars (NS) that hit the atmosphere can produce lethal fluxes of atmospheric muons at ground level, underground and underwater, destroy the ozone layer and radioactivate the environment. They could have caused most of the massive life extinctions on planet Earth in the past 600 My. Biological mutations due to ionizing radiations could have caused the fast appearance of new species after the massive extinctions. An early warning of future extinctions due to NS mergers may be obtained by identifying, mapping and timing all the nearby binary neutron stars systems. A warning of an approaching cosmic ray burst from a nearby NS merger/AIC may be provided by a very intense gamma ray burst which preceeds it.

  4. Mammal extinctions, body size, and paleotemperature

    Science.gov (United States)

    Bown, T.M.; Holroyd, P.A.; Rose, K.D.

    1994-01-01

    There is a general inverse relationship between the natural logarithm of tooth area (a body size indicator) of some fossil mammals and paleotemperature during approximately 2.9 million years of the early Eocene in the Bighorn Basin of northwest Wyoming. When mean temperatures became warmer, tooth areas tended to become smaller. During colder times, larger species predominated; these generally became larger or remained the same size. Paleotemperature trends also markedly affected patterns of local (and, perhaps, regional) extinction and immigration. New species appeared as immigrants during or near the hottest (smaller forms) and coldest (larger forms) intervals. Paleotemperature trend reversals commonly resulted in the ultimate extinction of both small forms (during cooling intervals) and larger forms (during warming intervals). These immigrations and extinctions mark faunal turnovers that were also modulated by sharp increases in sediment accumulation rate.

  5. Does supplementary reinforcement of stereotypy facilitate extinction?

    Science.gov (United States)

    Dozier, Claudia L; Iwata, Brian A; Wilson, David M; Thomason-Sassi, Jessica L; Roscoe, Eileen M

    2013-01-01

    Results of several studies suggest that delivery of supplemental (social) reinforcement for stereotypy might facilitate its subsequent extinction. We examined this possibility with 9 subjects who engaged in stereotypy by including methodological refinements to ensure that (a) subjects' stereotypy was maintained in the absence of social consequences, (b) supplementary reinforcers were highly preferred and were shown to be reinforcers for some behavior, and (c) subjects were exposed to lengthy reinforcement and extinction conditions. In spite of these modifications, only 4 subjects' stereotypy increased when supplementary reinforcement was delivered contingent on stereotypy, and no subject's stereotypy decreased below initial baseline levels when social reinforcement was subsequently withheld. Decreases in stereotypy occurred with the implementation of noncontingent reinforcement. Thus, delivery of supplementary reinforcers either did not increase stereotypy or did not facilitate extinction of stereotypy maintained by automatic reinforcement. We discuss the practical and conceptual bases of these results with respect to our current understanding of function-based interventions.

  6. Opportunities and costs for preventing vertebrate extinctions

    DEFF Research Database (Denmark)

    Conde, Dalia Amor; Colchero, Fernando; Güneralp, Burak

    2015-01-01

    -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...... 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...... 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...

  7. Extinction in four species cyclic competition

    Science.gov (United States)

    Intoy, Ben; Pleimling, Michel

    2013-08-01

    When four species compete stochastically in a cyclic way, the formation of two teams of mutually neutral partners is observed. In this paper we study through numerical simulations the extinction processes that can take place in this system both in the well mixed case as well as on different types of lattices. The different routes to extinction are revealed by the probability distribution of the domination time, i.e. the time needed for one team to fully occupy the system. If swapping is allowed between neutral partners, then the probability distribution is dominated by very long-lived states where a few very large domains persist, each domain being occupied by a mix of individuals from species that form one of the teams. Many aspects of the possible extinction scenarios are lost when only considering averaged quantities, such as for example the mean domination time.

  8. Opportunities and costs for preventing vertebrate extinctions

    DEFF Research Database (Denmark)

    Conde, Dalia Amor; Colchero, Fernando; Güneralp, Burak

    2015-01-01

    -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...... 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...... 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...

  9. Molecular genetic analysis of a cattle population to reconstitute the extinct Algarvia breed

    Directory of Open Access Journals (Sweden)

    Rangel-Figueiredo Teresa

    2010-06-01

    Full Text Available Abstract Background Decisions to initiate conservation programmes need to account for extant variability, diversity loss and cultural and economic aspects. Molecular markers were used to investigate if putative Algarvia animals could be identified for use as progenitors in a breeding programme to recover this nearly extinct breed. Methods 46 individuals phenotypically representative of Algarvia cattle were genotyped for 27 microsatellite loci and compared with 11 Portuguese autochthonous and three imported breeds. Genetic distances and factorial correspondence analyses (FCA were performed to investigate the relationship among Algarvia and related breeds. Assignment tests were done to identify representative individuals of the breed. Y chromosome and mtDNA analyses were used to further characterize Algarvia animals. Gene- and allelic-based conservation analyses were used to determine breed contributions to overall genetic diversity. Results Genetic distance and FCA results confirmed the close relationship between Algarvia and southern Portuguese breeds. Assignment tests without breed information classified 17 Algarvia animals in this cluster with a high probability (q > 0.95. With breed information, 30 cows and three bulls were identified (q > 0.95 that could be used to reconstitute the Algarvia breed. Molecular and morphological results were concordant. These animals showed intermediate levels of genetic diversity (MNA = 6.0 ± 1.6, Rt = 5.7 ± 1.4, Ho = 0.63 ± 0.19 and He = 0.69 ± 0.10 relative to other Portuguese breeds. Evidence of inbreeding was also detected (Fis = 0.083, P st = 0.028, P > 0.05. Algarvia cattle provide an intermediate contribution (CB = 6.18, CW = -0.06 and D1 = 0.50 to the overall gene diversity of Portuguese cattle. Algarvia and seven other autochthonous breeds made no contribution to the overall allelic diversity. Conclusions Molecular analyses complemented previous morphological findings to identify 33 animals that

  10. Molecular genetic analysis of a cattle population to reconstitute the extinct Algarvia breed

    Science.gov (United States)

    2010-01-01

    Background Decisions to initiate conservation programmes need to account for extant variability, diversity loss and cultural and economic aspects. Molecular markers were used to investigate if putative Algarvia animals could be identified for use as progenitors in a breeding programme to recover this nearly extinct breed. Methods 46 individuals phenotypically representative of Algarvia cattle were genotyped for 27 microsatellite loci and compared with 11 Portuguese autochthonous and three imported breeds. Genetic distances and factorial correspondence analyses (FCA) were performed to investigate the relationship among Algarvia and related breeds. Assignment tests were done to identify representative individuals of the breed. Y chromosome and mtDNA analyses were used to further characterize Algarvia animals. Gene- and allelic-based conservation analyses were used to determine breed contributions to overall genetic diversity. Results Genetic distance and FCA results confirmed the close relationship between Algarvia and southern Portuguese breeds. Assignment tests without breed information classified 17 Algarvia animals in this cluster with a high probability (q > 0.95). With breed information, 30 cows and three bulls were identified (q > 0.95) that could be used to reconstitute the Algarvia breed. Molecular and morphological results were concordant. These animals showed intermediate levels of genetic diversity (MNA = 6.0 ± 1.6, Rt = 5.7 ± 1.4, Ho = 0.63 ± 0.19 and He = 0.69 ± 0.10) relative to other Portuguese breeds. Evidence of inbreeding was also detected (Fis = 0.083, P 0.05). Algarvia cattle provide an intermediate contribution (CB = 6.18, CW = -0.06 and D1 = 0.50) to the overall gene diversity of Portuguese cattle. Algarvia and seven other autochthonous breeds made no contribution to the overall allelic diversity. Conclusions Molecular analyses complemented previous morphological findings to identify 33 animals that can be considered remnants of the

  11. Abrupt climate change and extinction events

    Science.gov (United States)

    Crowley, Thomas J.

    1988-01-01

    There is a growing body of theoretical and empirical support for the concept of instabilities in the climate system, and indications that abrupt climate change may in some cases contribute to abrupt extinctions. Theoretical indications of instabilities can be found in a broad spectrum of climate models (energy balance models, a thermohaline model of deep-water circulation, atmospheric general circulation models, and coupled ocean-atmosphere models). Abrupt transitions can be of several types and affect the environment in different ways. There is increasing evidence for abrupt climate change in the geologic record and involves both interglacial-glacial scale transitions and the longer-term evolution of climate over the last 100 million years. Records from the Cenozoic clearly show that the long-term trend is characterized by numerous abrupt steps where the system appears to be rapidly moving to a new equilibrium state. The long-term trend probably is due to changes associated with plate tectonic processes, but the abrupt steps most likely reflect instabilities in the climate system as the slowly changing boundary conditions caused the climate to reach some threshold critical point. A more detailed analysis of abrupt steps comes from high-resolution studies of glacial-interglacial fluctuations in the Pleistocene. Comparison of climate transitions with the extinction record indicates that many climate and biotic transitions coincide. The Cretaceous-Tertiary extinction is not a candidate for an extinction event due to instabilities in the climate system. It is quite possible that more detailed comparisons and analysis will indicate some flaws in the climate instability-extinction hypothesis, but at present it appears to be a viable candidate as an alternate mechanism for causing abrupt environmental changes and extinctions.

  12. Extinction Mapping of Nearby Galaxies Using LEGUS

    Science.gov (United States)

    Kahre, Lauren; Walterbos, Rene A. M.; Calzetti, Daniela; Sabbi, Elena; Ubeda, Leonardo; LEGUS Collaboration

    2017-01-01

    Extinction by dust affects studies of star formation and stellar evolution in galaxies. There are different ways to measure the distribution of dust column densities across galaxies. Here we present work based on extinctions measured towards individual massive stars.Isochrones of massive stars lie in the same location on a color-color diagram with little dependence on metallicity and luminosity class, so the extinction can be directly derived from the observed photometry. We develop a method for generating extinction maps using photometry of massive stars from the Hubble Space Telescope for the nearly 50 galaxies observed by the Legacy Extragalactic Ultraviolet Survey (LEGUS). The derived extinction maps will allow us to correct ground-based and HST Halpha maps for extinction, and will be used to constrain changes in the dust-to-gas ratio across the galaxy sample and in different star formation, metallicity and morphological environments. Previous studies have found links between galaxy metallicity and the dust-to-gas mass ratio. Dust abundance and gas metallicity are critical constraints for chemical and galaxy evolution models. We present a study of LEGUS galaxies spanning a range of distances, metallicities, and galaxy morphologies, including metal-poor dwarfs Holmberg I and II and giant spirals NGC 6503 and NGC 628. We see clear evidence for changes in the dust-to-gas mass ratio with changing metallicity. We also examine changes in the dust-to-gas mass ratio with galactocentric radius. Ultimately, we will provide constraints on the dust-to-gas mass ratio across a wide range of galaxy environments.

  13. Animal ethics

    DEFF Research Database (Denmark)

    Palmer, Clare; Sandøe, Peter

    2011-01-01

    This chapter describes and discusses different views concerning our duties towards animals. First, we explain why it is necessary to engage in thinking about animal ethics and why it is not enough to rely on feelings alone. Secondly, we present and discuss five different kinds of views about...

  14. Kindergarten Animation

    Science.gov (United States)

    Hinshaw, Craig

    2012-01-01

    Animation is one of the last lessons that come to mind when thinking of kindergarten art. The necessary understanding of sequencing, attention to small, often detailed drawings, and the use of technology all seem more suitable to upper elementary. With today's emphasis on condensing and integrating curriculum, consider developing animation lessons…

  15. Animal Detectives

    Science.gov (United States)

    Mulvey, Bridget; Warnock, Carly

    2015-01-01

    During a two-week inquiry-based 5E learning cycle unit, children made observations and inferences to guide their explorations of animal traits and habitats (Bybee 2014). The children became "animal detectives" by studying a live-feed webcam and digital images of wolves in their natural habitat, reading books and online sources about…

  16. Animal Detectives

    Science.gov (United States)

    Mulvey, Bridget; Warnock, Carly

    2015-01-01

    During a two-week inquiry-based 5E learning cycle unit, children made observations and inferences to guide their explorations of animal traits and habitats (Bybee 2014). The children became "animal detectives" by studying a live-feed webcam and digital images of wolves in their natural habitat, reading books and online sources about…

  17. Kindergarten Animation

    Science.gov (United States)

    Hinshaw, Craig

    2012-01-01

    Animation is one of the last lessons that come to mind when thinking of kindergarten art. The necessary understanding of sequencing, attention to small, often detailed drawings, and the use of technology all seem more suitable to upper elementary. With today's emphasis on condensing and integrating curriculum, consider developing animation lessons…

  18. Extinction rate fragility in population dynamics.

    Science.gov (United States)

    Khasin, M; Dykman, M I

    2009-08-01

    Population extinction is of central interest for population dynamics. It may occur from a large rare fluctuation. We find that, in contrast to related large-fluctuation effects like noise-induced interstate switching, quite generally extinction rates in multipopulation systems display fragility, where the height of the effective barrier to be overcome in the fluctuation depends on the system parameters nonanalytically. We show that one of the best-known models of epidemiology, the susceptible-infectious-susceptible model, is fragile to total population fluctuations.

  19. On the Atmospheric Extinction Reduction Procedure in Multiband Wide-Field Photometric Surveys

    CERN Document Server

    Zakharov, A; Biryukov, A; Kroussanova, N; Prokhorov, M; Beskin, G; Karpov, S; Bondar, S; Ivanov, E; Perkov, A; Sasyuk, V

    2015-01-01

    We propose an improved method for the atmospheric extinction reduction within optical photometry. Our method is based on the simultaneous multicolor observations of photometric standards. Such data are now available within the modern wide-field sky surveys and contain a large amount of information about instant atmospheric conditions. So, it became possible to estimate the extinction parameters on the basis of a quite short observational dataset and, hence, to trace the rapid stars twinkling accurately. Having been developed for a new MiniMegaTORTORA observational system, the proposed method can be adopted for a wide range of modern observational programs.

  20. Extinction space--a method for the quantification and classification of changes in morphospace across extinction boundaries.

    Science.gov (United States)

    Korn, Dieter; Hopkins, Melanie J; Walton, Sonny A

    2013-10-01

    Three main modes of extinction are responsible for reductions in morphological disparity: (1) random (caused by a nonselective extinction event); (2) marginal (a symmetric, selective extinction event trimming the margin of morphospace); and (3) lateral (an asymmetric, selective extinction event eliminating one side of the morphospace). These three types of extinction event can be distinguished from one another by comparing changes in three measures of morphospace occupation: (1) the sum of range along the main axes; (2) the sum of variance; and (3) the position of the centroid. Computer simulations of various extinction events demonstrate that the pre-extinction distribution of taxa (random or normal) in the morphospace has little influence on the quantification of disparity changes, whereas the modes of the extinction events play the major role. Together, the three disparity metrics define an "extinction-space" in which different extinction events can be directly compared with one another. Application of this method to selected extinction events (Frasnian-Famennian, Devonian-Carboniferous, and Permian-Triassic) of the Ammonoidea demonstrate the similarity of the Devonian events (selective extinctions) but the striking difference from the end-Permian event (nonselective extinction). These events differ in their mode of extinction despite decreases in taxonomic diversity of similar magnitude.

  1. Linking Indices for Biodiversity Monitoring to Extinction Risk Theory

    Science.gov (United States)

    Mccarthy, Michael A; Moore, Alana L; Krauss, Jochen; Morgan, John W; Clements, Christopher F

    2014-01-01

    Biodiversity indices often combine data from different species when used in monitoring programs. Heuristic properties can suggest preferred indices, but we lack objective ways to discriminate between indices with similar heuristics. Biodiversity indices can be evaluated by determining how well they reflect management objectives that a monitoring program aims to support. For example, the Convention on Biological Diversity requires reporting about extinction rates, so simple indices that reflect extinction risk would be valuable. We developed 3 biodiversity indices that are based on simple models of population viability that relate extinction risk to abundance. We based the first index on the geometric mean abundance of species and the second on a more general power mean. In a third index, we integrated the geometric mean abundance and trend. These indices require the same data as previous indices, but they also relate directly to extinction risk. Field data for butterflies and woodland plants and experimental studies of protozoan communities show that the indices correlate with local extinction rates. Applying the index based on the geometric mean to global data on changes in avian abundance suggested that the average extinction probability of birds has increased approximately 1% from 1970 to 2009. Conectando Índices para el Monitoreo de la Biodiversidad con la Teoría de Riesgo de Extinción Resumen Los índices de biodiversidad combinan frecuentemente los datos de diferentes especies cuando se usan en los programas de monitoreo. Las propiedades heurísticas pueden sugerir índices preferidos, pero carecemos de medios objetivos para discriminar a los índices con propiedades heurísticas similares. Los índices de biodiversidad pueden evaluarse al determinar qué tan bien reflejan los objetivos de manejo que un programa de monitoreo busca apoyar. Por ejemplo, la Convención sobre la Diversidad Biológica requiere reportar las tasas de extinción, así que los

  2. Effect of environmental variables on body size evolution of crinoids between periods of mass extinctions

    Science.gov (United States)

    Jani, T.; Heim, N. A.; Payne, J.

    2013-12-01

    Body size plays a major role in determining whether or not an organism can sustain in its local environment. The ecosystem of an animal has a major effect on the fitness of organisms, and it would be interesting to note the degree to which various environmental factors alter body size. In my project, I identify three environmental factors that seem to affect body size of crinoids, marine invertebrates from phylum Echinodermata, and explore how these variables play out in the intervals between the five mass extinctions. The particular factors I study include atmospheric CO2 concentration (proxy for temperature), O2 concentration, and sea level. Although the r and p values for all of these factors were statistically insignificant to definitively make any correlation, there was a visual correlation. For O2, I noted a generally positive correlation with body size over time. CO2 trends suggested a negative correlation until the K-T boundary, but a positive correlation afterwards. Correlation with sea level was a little more complicated: correlation was positive from the start of the Phanerozoic to the Permian extinction; it turned negative until the Cretaceous-Tertiary boundary; afterwards, it again became positive. However, for all three variables, statistical values are too low to say definitively mark any correlation. Out of all three factors, CO2 levels had the highest correlation and lowest p-values in the most time intervals: from the start of the Phanerozoic to Ordovician-Silurian Extinction, from the Late Devonian to the Permian Extinction, and from the Cretaceous-Tertiary boundary to the present. When considering first differences, CO2 levels also had the highest correlation from the Permian Extinction to Triassic-Jurassic Extinction and from the Triassic-Jurassic Extinction to Cretaceous-Tertiary Extinction. Using PaleoTS, I found that body size evolution patterns either seemed to follow either an unbiased random walk (URW) or stasis in the intervals between

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

    Directory of Open Access Journals (Sweden)

    Bram eVervliet

    2015-12-01

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

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

    Science.gov (United States)

    Vervliet, Bram; Indekeu, Ellen

    2015-01-01

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

  5. Animal Transports

    Directory of Open Access Journals (Sweden)

    Diana Ludrovcová

    2016-08-01

    Full Text Available Purpose and Originality: The research is aimed to the animal transports issue, from two points of view – first is the animal cruelty and second is the policy and economic consideration. The goal is to acquaint the readers with the transports risks and its cruelty and evaluation of the economic, political aspects for he involved countries. The study is oriented on more points of view, what is rare in works with a similar theme. Method: This paper examines many issues and examinations from different authors and subsequently summarized the findings with authors own knowledge to one expanded unit. Results: Results proves, that livestock transports have negative impact on animal´s health, environment. Number of transported animals is rising every year. Society: Research familiarize the society with the animal transports, cruelty against animals during them, and influence of transports on some countries, their economy, policy. People get better informed and can form their own opinion on this topic. They may start acting, undertaking some steps to improve the present situation, what could help a lot to animals and environment. Limitations / further research: Future research could show progress and improvement of transports, quality of food supply and economics.

  6. Animal experimentation.

    Science.gov (United States)

    Kolar, Roman

    2006-01-01

    Millions of animals are used every year in often times extremely painful and distressing scientific procedures. Legislation of animal experimentation in modern societies is based on the supposition that this is ethically acceptable when certain more or less defined formal (e.g. logistical, technical) demands and ethical principles are met. The main parameters in this context correspond to the "3Rs" concept as defined by Russel and Burch in 1959, i.e. that all efforts to replace, reduce and refine experiments must be undertaken. The licensing of animal experiments normally requires an ethical evaluation process, often times undertaken by ethics committees. The serious problems in putting this idea into practice include inter alia unclear conditions and standards for ethical decisions, insufficient management of experiments undertaken for specific (e.g. regulatory) purposes, and conflicts of interest of ethics committees' members. There is an ongoing societal debate about ethical issues of animal use in science. Existing EU legislation on animal experimentation for cosmetics testing is an example of both the public will for setting clear limits to animal experiments and the need to further critically examine other fields and aspects of animal experimentation.

  7. Animal Bioacoustics

    Science.gov (United States)

    Fletcher, Neville H.

    Animals rely upon their acoustic and vibrational senses and abilities to detect the presence of both predators and prey and to communicate with members of the same species. This chapter surveys the physical bases of these abilities and their evolutionary optimization in insects, birds, and other land animals, and in a variety of aquatic animals other than cetaceans, which are treated in Chap. 20. While there are many individual variations, and some animals devote an immense fraction of their time and energy to acoustic communication, there are also many common features in their sound production and in the detection of sounds and vibrations. Excellent treatments of these matters from a biological viewpoint are given in several notable books [19.1,2] and collections of papers [19.3,4,5,6,7,8], together with other more specialized books to be mentioned in the following sections, but treatments from an acoustical viewpoint [19.9] are rare. The main difference between these two approaches is that biological books tend to concentrate on anatomical and physiological details and on behavioral outcomes, while acoustical books use simplified anatomical models and quantitative analysis to model vocalization frequency scaling in animals hearing sound production animal animal biological biological bioacoustics whole-system behavior. This latter is the approach to be adopted here.

  8. End-Permian Mass Extinction in the Oceans: An Ancient Analog for the Twenty-First Century?

    Science.gov (United States)

    Payne, Jonathan L.; Clapham, Matthew E.

    2012-05-01

    The greatest loss of biodiversity in the history of animal life occurred at the end of the Permian Period (˜252 million years ago). This biotic catastrophe coincided with an interval of widespread ocean anoxia and the eruption of one of Earth's largest continental flood basalt provinces, the Siberian Traps. Volatile release from basaltic magma and sedimentary strata during emplacement of the Siberian Traps can account for most end-Permian paleontological and geochemical observations. Climate change and, perhaps, destruction of the ozone layer can explain extinctions on land, whereas changes in ocean oxygen levels, CO2, pH, and temperature can account for extinction selectivity across marine animals. These emerging insights from geology, geochemistry, and paleobiology suggest that the end-Permian extinction may serve as an important ancient analog for twenty-first century oceans.

  9. Animal Flicker

    Directory of Open Access Journals (Sweden)

    Érik Bullot

    2016-11-01

    Full Text Available Leafing a book quickly creates metamorphoses of its images and illustrations. Cinema as a medium is based on such visual discontinuity.  Both Paolo Gioli, the Italian filmmaker, and Stan Brakhage in America,  made very interesting flicker films with and about insects and butterflies : Farfallìo (1993 and Mothlight (1963. Is the buttefly miming the filmic device? To what extent has a film to disguise its mechanism? What is the relation between animation and the animal? I intend to scrutinize the link between flicker film and animality in regard of camouflage and mimicry.

  10. Wild Animals

    Institute of Scientific and Technical Information of China (English)

    宁静

    2005-01-01

    Many of us think that all wild animals are dangerous. In fact, very few of them will eat a man if he leaves them alone. If you meet a tiger, I'm sure you will run away, but even a tiger doesn't like meeting a man if it isn't hungry. Tigers only kill and eat man when they are too old to catch their food, such as sheep and other small animals. Some animals get frightened when they only smell a man. Some of themst and and look at a man for a short time before they run away.

  11. Effects of a Mere-Presence Conspecific on Extinction of an Operant.

    Science.gov (United States)

    Huang, I N; Wood, G A

    1984-01-01

    In a 2 × 2 factorial design, 32 hunger-motivated albino rats were trained to press a bar for food in a Skinner box. Animals practiced this operant, with or without a mere-presence conspecific, on a VR reinforcement schedule for 10 days and were extinguished with or without a conspecific in a nearby compartment. The results showed that the presence of a conspecific did not enhance this operant during practice sessions nor its resistance to extinction. During extinction the animals that experienced the presence or absence of a conspecific for the first time showed a reduced rate of responding. The findings cast doubt on a drive theory of social facilitation and support a generalization-decrement hypothesis.

  12. The Optical-Infrared Extinction Curve and its Variation in the Milky Way

    CERN Document Server

    Schlafly, E F; Stutz, A M; Kainulainen, J; Peek, J E G; Tchernyshyov, K; Rix, H -W; Finkbeiner, D P; Covey, K R; Green, G M; Bell, E F; Burgett, W S; Chambers, K C; Draper, P W; Flewelling, H; Hodapp, K W; Kaiser, N; Magnier, E A; Martin, N F; Metcalfe, N; Wainscoat, R J; Waters, C

    2016-01-01

    The dust extinction curve is a critical component of many observational programs and an important diagnostic of the physics of the interstellar medium. Here we present new measurements of the dust extinction curve and its variation towards tens of thousands of stars, a hundred-fold larger sample than in existing detailed studies. We use data from the APOGEE spectroscopic survey in combination with ten-band photometry from Pan-STARRS1, 2MASS, and WISE. We find that the extinction curve in the optical through infrared is well characterized by a one-parameter family of curves described by R(V). The extinction curve is more uniform than suggested in past works, with sigma(R(V)) = 0.18, and with less than one percent of sight lines having R(V) > 4. Our data and analysis have revealed two new aspects of Galactic extinction: first, we find significant, wide-area variations in R(V) throughout the Galactic plane. These variations are on scales much larger than individual molecular clouds, indicating that R(V) variatio...

  13. The Optical-infrared Extinction Curve and Its Variation in the Milky Way

    Science.gov (United States)

    Schlafly, E. F.; Meisner, A. M.; Stutz, A. M.; Kainulainen, J.; Peek, J. E. G.; Tchernyshyov, K.; Rix, H.-W.; Finkbeiner, D. P.; Covey, K. R.; Green, G. M.; Bell, E. F.; Burgett, W. S.; Chambers, K. C.; Draper, P. W.; Flewelling, H.; Hodapp, K. W.; Kaiser, N.; Magnier, E. A.; Martin, N. F.; Metcalfe, N.; Wainscoat, R. J.; Waters, C.

    2016-04-01

    The dust extinction curve is a critical component of many observational programs and an important diagnostic of the physics of the interstellar medium. Here we present new measurements of the dust extinction curve and its variation toward tens of thousands of stars, a hundred-fold larger sample than in existing detailed studies. We use data from the APOGEE spectroscopic survey in combination with ten-band photometry from Pan-STARRS1, the Two Micron All-Sky Survey, and Wide-field Infrared Survey Explorer. We find that the extinction curve in the optical through infrared is well characterized by a one-parameter family of curves described by R(V). The extinction curve is more uniform than suggested in past works, with σ (R(V))=0.18, and with less than one percent of sight lines having R(V)\\gt 4. Our data and analysis have revealed two new aspects of Galactic extinction: first, we find significant, wide-area variations in R(V) throughout the Galactic plane. These variations are on scales much larger than individual molecular clouds, indicating that R(V) variations must trace much more than just grain growth in dense molecular environments. Indeed, we find no correlation between R(V) and dust column density up to E(B-V)≈ 2. Second, we discover a strong relationship between R(V) and the far-infrared dust emissivity.

  14. 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.

  15. 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

  16. 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 ex

  17. 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 addictions

  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. Attentional, Associative, and Configural Mechanisms in Extinction

    Science.gov (United States)

    Larrauri, Jose A.; Schmajuk, Nestor A.

    2008-01-01

    The participation of attentional and associative mechanisms in extinction, spontaneous recovery, external disinhibition, renewal, reinstatement, and reacquisition was evaluated through computer simulations with an extant computational model of classical conditioning (N. A. Schmajuk, Y. Lam, & J. A. Gray, 1996; N. A. Schmajuk & J. A. Larrauri,…

  20. 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…

  1. 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.

  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. Mass extinctions caused by large bolide impacts

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, L.W.

    1987-07-01

    Evidence indicates that the collision of Earth and a large piece of Solar System derbris such as a meteoroid, asteroid or comet caused the great extinctions of 65 million years ago, leading to the transition from the age of the dinosaurs to the age of the mammals.

  4. Self-extinction through optimizing selection

    Science.gov (United States)

    Parvinen, Kalle; Dieckmann, Ulf

    2013-01-01

    Evolutionary suicide is a process in which selection drives a viable population to extinction. So far, such selection-driven self-extinction has been demonstrated in models with frequency-dependent selection. This is not surprising, since frequency-dependent selection can disconnect individual-level and population-level interests through environmental feedback. Hence it can lead to situations akin to the tragedy of the commons, with adaptations that serve the selfish interests of individuals ultimately ruining a population. For frequency-dependent selection to play such a role, it must not be optimizing. Together, all published studies of evolutionary suicide have created the impression that evolutionary suicide is not possible with optimizing selection. Here we disprove this misconception by presenting and analyzing an example in which optimizing selection causes self-extinction. We then take this line of argument one step further by showing, in a further example, that selection-driven self-extinction can occur even under frequency-independent selection. PMID:23583808

  5. Subwoofer and nanotube butterfly acoustic flame extinction

    Science.gov (United States)

    Aliev, Ali E.; Mayo, Nathanael K.; Baughman, Ray H.; Mills, Brent T.; Habtour, Ed

    2017-07-01

    Nonchemical flame control using acoustic waves from a subwoofer and a lightweight carbon nanotube thermoacoustic projector was demonstrated. The intent was to manipulate flame intensity, direction and propagation. The mechanisms of flame suppression using low frequency acoustic waves were discussed. Laminar flame control and extinction were achieved using a thermoacoustic ‘butterfly’ projector based on freestanding carbon nanotube sheets.

  6. Farm Animals

    Science.gov (United States)

    ... same bacterium that has become resistant to certain antibiotics, which can make infections harder to treat. MRSA can be passed back and forth between people and farm animals through direct contact. In humans, MRSA can cause ...

  7. Animation & Neurocinematics*

    DEFF Research Database (Denmark)

    Carpe Pérez, Inmaculada Concepción

    2016-01-01

    machines that think”-(Damasio, A. Descartes error). Such feelings come from the interpretation of the emotions in our bodies. Emotions are our universal language, the motivation of living, the key to what makes a movie successful and truly an art piece that you will remember because moves you. Animation......, indeed, can be considered a social/ emotional learning media, which goes beyond the limitations of live action movies. This is due to the diversity of techniques, and its visual plasticity that constructs the impossible. Animators are not real actors but more like the midwife who brings the anima...... into aliveness, which requires knowing how emotions work. Ed Hooks as an expert in training animators and actors, always remarks: “emotions tend to lead to action”. In this paper we want to argue that by producing animated films, as we watch them, cause a stronger effect, not only in our brains, but also in our...

  8. Animal Bites

    Science.gov (United States)

    ... to 15 to 20 of every 100 following dog or human bites. Treatment If your child is bleeding from ... dangerous than those from tame, immunized (against rabies) dogs and cats. The health of the animal also is important, so if ...

  9. Modeling the Infrared Extinction toward the Galactic Center

    CERN Document Server

    Gao, Jian; Jiang, B W

    2013-01-01

    We model the ~1--19$\\mum$ infrared (IR) extinction curve toward the Galactic Center (GC) in terms of the standard silicate-graphite interstellar dust model. The grains are taken to have a power law size distribution with an exponential decay above some size. The best-fit model for the GC IR extinction constrains the visual extinction to be Av~38--42 mag. The limitation of the model, i.e., its difficulty in simultaneously reproducing both the steep ~1--3$\\mum$ near-IR extinction and the flat ~3--8$\\mum$ mid-IR extinction is discussed. We argue that this difficulty could be alleviated by attributing the extinction toward the GC to a combination of dust in different environments: dust in diffuse regions (characterized by small Rv and steep near-IR extinction), and dust in dense regions (characterized by large Rv and flat UV extinction).

  10. A REMARK ON EXTINCTION OF A CLASS OF SUPERPROCESSES

    Institute of Scientific and Technical Information of China (English)

    ZHAOXUELEI

    1996-01-01

    The extinction of a class of superprocesses associated with general branching characteristics and underlying Markov processes is investigted, The extinction is closely associated with the branching characteristics and the recurrence and transience of underlying processes.

  11. Inferring modern extinction risk from fossil occupancy trajectories

    Science.gov (United States)

    Kiessling, Wolfgang; Kocsis, Adam

    2016-04-01

    Besides providing information on ancient mass extinctions and intrinsic extinction risk, the fossil record may also provide useful data for assessing the extinction risk of extant species. Here we analyse the palaeontological trajectories of geographical occupancy in extant marine species to identify species that have been declining over geological time scales and may thus be more prone to extinction than expanding species. The slopes of these occupancy trajectories are used to categorize evolutionary extinction risk. Mapping the risk at global scale we find that low to mid latitude regions are at significantly higher risk than high latitude regions. We also find a moderate correspondence between high extinction risk on geological time scales and modern extinction risk for reef corals and propose to add fossil data to the assessment of current extinction risk, especially for the notoriously data deficient marine taxa.

  12. Angiotensin-(1-7)/Mas axis modulates fear memory and extinction in mice.

    Science.gov (United States)

    Lazaroni, Thiago Luiz do Nascimento; Bastos, Cristiane Perácio; Moraes, Márcio Flávio Dutra; Santos, Robson Souza; Pereira, Grace Schenatto

    2016-01-01

    Inappropriate defense-alerting reaction to fear is a common feature of neuropsychiatric diseases. Therefore, impairments in brain circuits, as well as in molecular pathways underlying the neurovegetative adjustments to fear may play an essential role on developing neuropsychiatric disorders. Here we tested the hypothesis that interfering with angiotensin-(1-7) [Ang-(1-7)]/Mas receptor axis homeostasis, which appears to be essential to arterial pressure control, would affect fear memory and extinction. Mas knockout (MasKO) mice, in FVB/N background, showed normal cued fear memory and extinction, but increased freezing in response to context. Next, as FVB/N has poor performance in contextual fear memory, we tested MasKO in mixed 129xC57BL/6 background. MasKO mice behaved similarly to wild-type (WT), but memory extinction was slower in contextual fear conditioning to a weak protocol (1CS/US). In addition, delayed extinction in MasKO mice was even more pronounced after a stronger protocol (3CS/US). We showed previously that Angiotensin II receptor AT1 antagonist, losantan, rescued object recognition memory deficit in MasKO mice. Here, losartan was also effective. Memory extinction was accelerated in MasKO mice after treatment with losartan. In conclusion, we showed for the first time that Ang-(1-7)/Mas axis may modulate fear memory extinction. Furthermore, we suggest MasKO mice as an animal model to study post-traumatic stress disorder (PTSD). Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Separation of time-based and trial-based accounts of the partial reinforcement extinction effect.

    Science.gov (United States)

    Bouton, Mark E; Woods, Amanda M; Todd, Travis P

    2014-01-01

    Two appetitive conditioning experiments with rats examined time-based and trial-based accounts of the partial reinforcement extinction effect (PREE). In the PREE, the loss of responding that occurs in extinction is slower when the conditioned stimulus (CS) has been paired with a reinforcer on some of its presentations (partially reinforced) instead of every presentation (continuously reinforced). According to a time-based or "time-accumulation" view (e.g., Gallistel and Gibbon, 2000), the PREE occurs because the organism has learned in partial reinforcement to expect the reinforcer after a larger amount of time has accumulated in the CS over trials. In contrast, according to a trial-based view (e.g., Capaldi, 1967), the PREE occurs because the organism has learned in partial reinforcement to expect the reinforcer after a larger number of CS presentations. Experiment 1 used a procedure that equated partially and continuously reinforced groups on their expected times to reinforcement during conditioning. A PREE was still observed. Experiment 2 then used an extinction procedure that allowed time in the CS and the number of trials to accumulate differentially through extinction. The PREE was still evident when responding was examined as a function of expected time units to the reinforcer, but was eliminated when responding was examined as a function of expected trial units to the reinforcer. There was no evidence that the animal responded according to the ratio of time accumulated during the CS in extinction over the time in the CS expected before the reinforcer. The results thus favor a trial-based account over a time-based account of extinction and the PREE. This article is part of a Special Issue entitled: Associative and Temporal Learning.

  14. Grey Milky Way Extinction from SDSS Stellar Photometry

    OpenAIRE

    Gorbikov, Evgeny; Brosch, Noah

    2009-01-01

    We report results concerning the distribution and properties of galactic extinction at high galactic latitudes derived from stellar statistics using the Sloan Digital Sky Survey (SDSS). We use the classical Wolf diagram method to identify regions with extinction, and derive the extinction and the extinction law of the dust using all five SDSS spectral bands. We estimate the distance to the extinguishing medium using simple assumptions about the stellar populations in the line of sight. We rep...

  15. Wizards of Animation.

    Science.gov (United States)

    Bushweller, Kevin

    1997-01-01

    At the South Burlington (Vermont) High School Imaging Lab, students are learning to manipulate the animation technology that NASA uses to design rockets, Hollywood uses to make movies, and architects use to design buildings. Assisted by grants, an English teacher parlayed a single unused computer into a nationally recognized program that helps…

  16. 2-D Animation's Not Just for Mickey Mouse.

    Science.gov (United States)

    Weinman, Lynda

    1995-01-01

    Discusses characteristics of two-dimensional (2-D) animation; highlights include character animation, painting issues, and motion graphics. Sidebars present Silicon Graphics animations tools and 2-D animation programs for the desktop computer. (DGM)

  17. Video animation system

    Energy Technology Data Exchange (ETDEWEB)

    Mareda, J.

    1985-01-01

    A video animation system is being used at Sandia Laboratories in Albuquerque to record computer generated images directly onto 3/4'' videocassettes. The system serves as a quick turn around process for previewing sequences prior to sending them to a Dicomed film recorder. It is also used when videocassette is appropriate for final output. The video animation system in place at Sandia is described. The system consists of a medium resolution graphics display system, a 3/4'' professional quality videocassette recorder, and a controller that allows single frame recording of computer generated images to be performed under program control. Examples of output produced using this system are presented which will include animated sequences of scientific data produced by DISSPLA programs.

  18. Towards mouse models of perseveration: a heritable component in extinction of operant behavior in fourteen standard and recombinant inbred mouse lines.

    Science.gov (United States)

    Malkki, Hemi A I; Donga, Laura A B; de Groot, Sabine E; Battaglia, Francesco P; Pennartz, Cyriel M A

    2011-09-01

    Extinction of instrumental responses is an essential skill for adaptive behavior such as foraging. So far, only few studies have focused on extinction following appetitive conditioning in mice. We studied extinction of appetitive operant lever-press behavior in six standard inbred mouse strains (A/J, C3H/HeJ, C57BL/6J, DBA/2J, BALB/cByJ and NOD/Ltj) and eight recombinant inbred mouse lines. From the response rates at the end of operant and extinction training we computed an extinction index, with higher values indicating better capability to omit behavioral responding in absence of reward. This index varied highly across the mouse lines tested, and the variability was partially due to a significant heritable component of 12.6%. To further characterize the relationship between operant learning and extinction, we calculated the slope of the time course of extinction across sessions. While many strains showed a considerable capacity to omit responding when lever pressing was no longer rewarded, we found a few lines showing an abnormally high perseveration in lever press behavior, showing no decay in response scores over extinction sessions. No correlation was found between operant and extinction response scores, suggesting that appetitive operant learning and extinction learning are dissociable, a finding in line with previous studies indicating that these forms of learning are dependent on different brain areas. These data shed light on the heritable basis of extinction learning and may help develop animal models of addictive habits and other perseverative disorders, such as compulsive food seeking and eating.

  19. Hippocampal Erk Mechanisms Linking Prediction Error to Fear Extinction: Roles of Shock Expectancy and Contextual Aversive Valence

    Science.gov (United States)

    Huh, Kyu Hwan; Guzman, Yomayra F.; Tronson, Natalie C.; Guedea, Anita L.; Gao, Can; Radulovic, Jelena

    2009-01-01

    Extinction of fear requires learning that anticipated aversive events no longer occur. Animal models reveal that sustained phosphorylation of the extracellular signal-regulated kinase (Erk) in hippocampal CA1 neurons plays an important role in this process. However, the key signals triggering and regulating the activity of Erk are not known. By…

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

    NARCIS (Netherlands)

    Kleine, R.A. de; Smits, J.A.J.; Hendriks, G.J.; Becker, E.S.; Rinck, M.

    2015-01-01

    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

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

    NARCIS (Netherlands)

    Kleine, R.A. de; Smits, J.A.; Hendriks, G.J.; Becker, E.S.; Minnen, A. van

    2015-01-01

    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 e

  2. Far-Ultraviolet Dust Scattering and Extinction in IC 405

    Science.gov (United States)

    France, Kevin; Burgh, Eric B.; McCandliss, Stephan R.; Feldman, Paul D.

    We present results from a NASA/JHU sounding rocket mission (36.198 UG) during which we acquired a longslit (12" times 200") spectrum of the reflection nebula IC 405 in the 900 - 1400Å wavelength region. Several pointings within the nebula were obtained, including a high quality (S/N ≅10-15 at R = 300) spectrum of the central star, HD 34078. Observations of the nebula reveal a surface brightness to stellar flux ratio that rises by two orders of magnitude to the blue in our bandpass. This is in contrast with the relatively flat nebular dust scattering observed during a prior sounding rocket observation of the reflection nebula NGC 2023. Several possibilities have been suggested to explain the blue rise that is exhibited in IC 405. Differential extinction within the nebula, such as a particular clump of dust along the line of sight, is one possibility. Fluorescent molecular hydrogen, unresolved by the resolution of the rocket experiment, is another possible explanation. Models of nebular dust scattering, similar to those of Burgh et al. 2002, have been compared to the data and results will be discussed. We will explore the possibility of differential extinction with an observing program to measure Balmer line ratios within the nebula with the Dual Imaging Spectrograph at Apache Point Observatory. Additionally, IC 405 has been accepted as a Cycle 4 target of the Far Ultraviolet Spectroscopic Explorer to search for emissions from molecular hydrogen at higher sensitivity and spectral resolution.

  3. 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.

  4. 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).

  5. 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,…

  6. Slower Reacquisition after Partial Extinction in Human Contingency Learning

    Science.gov (United States)

    Morís, Joaquín; Barberia, Itxaso; Vadillo, Miguel A.; Andrades, Ainhoa; López, Francisco J.

    2017-01-01

    Extinction is a very relevant learning phenomenon from a theoretical and applied point of view. One of its most relevant features is that relapse phenomena often take place once the extinction training has been completed. Accordingly, as extinction-based therapies constitute the most widespread empirically validated treatment of anxiety disorders,…

  7. 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,…

  8. Global distribution and drivers of language extinction risk

    DEFF Research Database (Denmark)

    Amano, Tatsuya; Sandel, Brody; Eager, Heidi;

    2014-01-01

    Many of the world's languages face serious risk of extinction. Efforts to prevent this cultural loss are severely constrained by a poor understanding of the geographical patterns and drivers of extinction risk. We quantify the global distribution of language extinction risk-represented by small...

  9. Estimating how many undescribed species have gone extinct.

    Science.gov (United States)

    Tedesco, P A; Bigorne, R; Bogan, A E; Giam, X; Jézéquel, C; Hugueny, B

    2014-10-01

    Because both descriptions of species and modern human-driven extinctions started around the same time (i.e., eighteenth century), a logical expectation is that a large proportion of species may have gone extinct without ever having been recorded. Despite this evident and widely recognized assumption, the loss of undescribed species has never been estimated. We quantified this loss for several taxonomic groups and regions for which undescribed species extinctions are likely to have occurred. Across a wide range of taxonomic groups, we applied known extinction rates computed from recorded species losses to assumed exponential decay in the proportion of species remaining undiscovered. Because all previous modeling attempts to project total species richness implicitly assumed that undescribed species extinctions could be neglected, we also evaluated the effect of neglecting them. Finally, because we assumed constant description and extinction probabilities, we applied our model to simulated data that did not conform to this assumption. Actual species losses were severely underestimated by considering only known species extinctions. According to our estimates, the proportion of undiscovered extinct species over all extinctions ranged from 0.15 to 0.59, depending on the taxonomic group and the region considered. This means that recent extinctions may be up to twice as large as the number recorded. When species differed in their extinction or description probabilities, our model underestimated extinctions of undescribed species by up to 20%. © 2014 Society for Conservation Biology.

  10. [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.

  11. 9 CFR 55.6 - Mortgage against animals.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Mortgage against animals. 55.6 Section 55.6 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF... DISEASE Chronic Wasting Disease Indemnification Program § 55.6 Mortgage against animals. When cervids...

  12. 9 CFR 54.3 - Animals eligible for indemnity payments.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Animals eligible for indemnity payments. 54.3 Section 54.3 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE... SCRAPIE Scrapie Indemnification Program § 54.3 Animals eligible for indemnity payments. (a) Indemnity...

  13. Facilitation of fear extinction by novelty depends on dopamine acting on D1-subtype dopamine receptors in hippocampus.

    Science.gov (United States)

    Menezes, Jefferson; Alves, Niége; Borges, Sidnei; Roehrs, Rafael; de Carvalho Myskiw, Jociane; Furini, Cristiane Regina Guerino; Izquierdo, Ivan; Mello-Carpes, Pâmela B

    2015-03-31

    Extinction is the learned inhibition of retrieval. Recently it was shown that a brief exposure to a novel environment enhances the extinction of contextual fear in rats, an effect explainable by a synaptic tagging-and-capture process. Here we examine whether this also happens with the extinction of another fear-motivated task, inhibitory avoidance (IA), and whether it depends on dopamine acting on D1 or D5 receptors. Rats were trained first in IA and then in extinction of this task. The retention of extinction was measured 24 h later. A 5-min exposure to a novel environment 30 min before extinction training enhanced its retention. Right after exposure to the novelty, animals were given bilateral intrahippocampal infusions of vehicle (VEH), of the protein synthesis inhibitor anisomycin, of the D1/D5 dopaminergic antagonist SCH23390, of the PKA inhibitor Rp-cAMP or of the PKC inhibitor Gö6976, and of the PKA stimulator Sp-cAMP or of the PKC stimulator PMA. The novelty increased hippocampal dopamine levels and facilitated the extinction, which was inhibited by intrahippocampal protein synthesis inhibitor anisomysin, D1/D5 dopaminerdic antagonist SCH23390, or PKA inhibitor Rp-cAMP and unaffected by PKC inhibitor Gö6976; additionally, the hippocampal infusion of PKA stimulator Sp-cAMP reverts the effect of D1/D5 dopaminergic antagonist SCH 23390, but the infusion of PKC stimulator PMA does not. The results attest to the generality of the novelty effect on fear extinction, suggest that it relies on synaptic tagging and capture, and show that it depends on hippocampal dopamine D1 but not D5 receptors.

  14. 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

    2013-09-01

    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 min 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 24h 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 Exp 1, 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.

  15. Animated symbols

    DEFF Research Database (Denmark)

    Frølunde, Lisbeth

    2008-01-01

    This paper is based on data about animation film production by 18-year-old students in a Danish upper secondary school. The optic is the on-going potential for learning and development of reflection. The purpose is to clarify what might support young people's reflection on media. I propose...... an analytic working model called Animated Symbols concerning critical reflection in a dialogic learning process. The model shows dialogue as interactions that involve two types of transformation: inner ‘learning processes' and outer signs and symbols. The classroom-based research study is part of a Ph...

  16. Mass Extinction in a Simple Mathematical Biological Model

    CERN Document Server

    Tokita, K; Tokita, Kei; Yasutomi, Ayumu

    1997-01-01

    Introducing the effect of extinction into the so-called replicator equations in mathematical biology, we construct a general model of ecosystems. The present model shows mass extinction by its own extinction dynamics when the system initially has a large number of species ( diversity). The extinction dynamics shows several significant features such as a power law in basin size distribution, induction time, etc. The present theory can be a mathematical foundation of the species-area effect in the paleontologic theory for mass extinction.

  17. Single-ended measurement of infrared extinction using lidar.

    Science.gov (United States)

    Murray, E R; Williams, M F; van der Laan, J E

    1978-01-15

    The goal of this study was to investigate the feasibility of single-ended measurement of the total extinction coefficient using an ir lidar system. Extinction was measured using a CO(2) laser radar system at four wavelengths near 10.3 microm. The measured results agree with theoretical estimates of extinction over a wide range. Single-ended measurements of extinction appear feasible to a horizontal range of 10 km using commercially available components. The system could potentially generate extinction data in a 3-D grid, enabling one to determine ir transmission between any two points in the field.

  18. PACAP modulates the consolidation and extinction of the contextual fear conditioning through NMDA receptors.

    Science.gov (United States)

    Schmidt, S D; Myskiw, J C; Furini, C R G; Schmidt, B E; Cavalcante, L E; Izquierdo, I

    2015-02-01

    Pituitary adenylate cyclase-activating polypeptide (PACAP) has a broad spectrum of biological functions including neurotransmitter, neurotrophic and neuroprotective. Moreover, it has been suggested that PACAP plays a role in the modulation of learning and memory as well as on the modulation of glutamate signaling. Thus, in the current study we investigated in the CA1 region of hippocampus and in the basolateral amygdala (BLA) the role of PACAP in the consolidation and extinction of contextual fear conditioning (CFC) and the interaction between PACAP and NMDA receptors. Male rats with cannulae implanted in the CA1 region of the hippocampus or in the BLA received immediately after the training or extinction training of the CFC infusions of the Vehicle, PACAP-38 (40 pg/side), PACAP 6-38 (40 pg/side) or PACAP 6-38 plus D-serine (50 μg/side). After 24h, the animals were subjected to a 3-min retention test. The results indicated that in the CA1 region of hippocampus, PACAP participates in the consolidation and extinction of the CFC, and in the BLA, PACAP participates only in the consolidation of the CFC. Additionally, the results suggest that the action of PACAP on the consolidation and extinction of the CFC is mediated by the glutamate NMDA receptors.

  19. Affective-associative two-process theory: a neurocomputational account of partial reinforcement extinction effects.

    Science.gov (United States)

    Lowe, Robert; Almér, Alexander; Billing, Erik; Sandamirskaya, Yulia; Balkenius, Christian

    2017-09-14

    The partial reinforcement extinction effect (PREE) is an experimentally established phenomenon: behavioural response to a given stimulus is more persistent when previously inconsistently rewarded than when consistently rewarded. This phenomenon is, however, controversial in animal/human learning theory. Contradictory findings exist regarding when the PREE occurs. One body of research has found a within-subjects PREE, while another has found a within-subjects reversed PREE (RPREE). These opposing findings constitute what is considered the most important problem of PREE for theoreticians to explain. Here, we provide a neurocomputational account of the PREE, which helps to reconcile these seemingly contradictory findings of within-subjects experimental conditions. The performance of our model demonstrates how omission expectancy, learned according to low probability reward, comes to control response choice following discontinuation of reward presentation (extinction). We find that a PREE will occur when multiple responses become controlled by omission expectation in extinction, but not when only one omission-mediated response is available. Our model exploits the affective states of reward acquisition and reward omission expectancy in order to differentially classify stimuli and differentially mediate response choice. We demonstrate that stimulus-response (retrospective) and stimulus-expectation-response (prospective) routes are required to provide a necessary and sufficient explanation of the PREE versus RPREE data and that Omission representation is key for explaining the nonlinear nature of extinction data.

  20. Extinction arouses attention to the context in a behavioral suppression method with humans.

    Science.gov (United States)

    Nelson, James Byron; Lamoureux, Jeffrey A; León, Samuel P

    2013-01-01

    One experiment assessed predictions from the attentional theory of context processing (ATCP, J. M. Rosas, J. E. Callejas-Aguilera, M. M. Ramos-Álvarez, & M. J. F. Abad, 2006, Revision of retrieval theory of forgetting: What does make information context-specific? International Journal of Psychology & Psychological Therapy, Vol. 6, pp. 147-166) that extinction arouses attention to contextual stimuli. In a video-game method, participants learned a biconditional discrimination (RG+/BG-/RY-/BY+) either after extinction of another stimulus had occurred, or not. When contextual stimuli were relevant to solving the discrimination (i.e., all RG+/BG- trials occurred in one context and all RY-/BY+ in another), prior extinction of another stimulus facilitated the discrimination, as if extinction enhanced attention to the contexts. Results are discussed briefly in terms of ATCP and the model of N. A. Schmajuk, Y. W. Lam, & J. A. Gray (1996, Latent inhibition: A neural network approach, Journal of Experimental Psychology: Animal Behavior Processes, Vol. 22, pp. 321-349).