Remember • Operant conditioning extinction differs from classical conditioning extinction • Responds decreases to near zero for both • Operant conditioning: - Transient increase - Extinction induced aggression Partial Reinforcement Extinction Effect: PREE • Extinction occurs at different rates depending on the schedule: - Continuous reinforcement: FAST extinction - Partial reinforcement schedules: SLOWER extinction - Variable schedules show slower extinction than fixed (rate or time) schedules. • PREE used to describe greater persistence in instrumental responding during extinction after partial (or intermittent) reinforcement training - Faster extinction after continuous reinforcement training. • Partial reinforcement schedules show RESISTANCE TO EXTINCTION Other Extinction Effects • magnitude reinforcement extinction effect - Less persistence of instrumental behavior in extinction following training with a large reinforcer - More persistance of responding with a small or moderate ...

TY - JOUR. T1 - Effects of linalool on extinction of mouse operant behaviour. T2 - Behavioural Pharmacology. AU - Shaw, D. AU - Norwood, Kelly. AU - Kennedy, Paul J.. AU - Leslie, J.C.. N1 - This paper is dedicated to the memory of our friend and colleague, David Shaw (1970-2017).. PY - 2020/2/1. Y1 - 2020/2/1. N2 - Linalool is an enanitomer monoterpene compound identified as the pharmacologically active constituent in a number of essential oils and has been reported to display anxiolytic properties in humans and in animal models and to exert both GABAergic and glutamatergic effects. In Experiment 1 linalool (100, 200, and 300, i.p.) had no significant effects compared with saline in an activity tracker with C57BL/6j mice. Experiment 2 assessed the effects on operant extinction with mice of chlordiazepoxide at a dose (15 mg/kg, i.p.) previously shown to facilitate extinction, and the same doses of linalool, compared with saline. Linalool had a dose-related facilitatory effect on extinction. ...

TY - JOUR. T1 - Lateral hypothalamus is required for context-induced reinstatement of extinguished reward seeking. AU - Marchant, N. J.. AU - Hamlin, A.S.. AU - McNally, G. P.. N1 - Imported on 12 Apr 2017 - DigiTool details were: month (773h) = Feb 2009; Journal title (773t) = Journal of Neuroscience. ISSNs: 0270-6474; PY - 2009/2. Y1 - 2009/2. N2 - We studied the role of lateral hypothalamus (LH) in context-induced reinstatement (renewal) of reward seeking. Rats were trained to respond for 4% (v/v) alcoholic beer or 10% (w/v) sucrose reward in one context (Context A) before extinction training in a second context (Context B). On test, rats were returned to the training context, A (ABA), or the extinction context, B (ABB). Return to the training context (ABA) produced robust reinstatement. Reversible inactivation of LH via baclofen/muscimol infusion prevented context-induced reinstatement of beer and sucrose seeking. This prevention was specific to bilateral infusions into LH. We then used the ...

Our results show that activation of noradrenergic β-receptors in IL during fear extinction is necessary for later retrieval of extinction. A β-receptor-mediated signaling cascade increases intrinsic excitability of IL pyramidal neurons and stabilizes extinction in IL. Thus, fear-induced activation of β-receptors engages cellular processes that enhance extinction learning.. It has been previously shown that lesions of the locus ceruleus, which deprive the entire cortex of NE, impair extinction (Mason and Fibiger, 1979; McCormick and Thompson, 1982), but these effects were never localized. Our findings indicate that the IL is a key site for noradrenergic modulation of extinction. The idea that NE facilitates consolidation of extinction was recently suggested by Berlau and McGaugh (2006), who showed that posttraining infusions of NE into the amygdala facilitated extinction of contextual fear in a β-receptor-dependent manner (Berlau and McGaugh, 2006). Infusion of propranolol alone, however, had ...

Extinction of conditioned fear forms a new memory in the infralimbic medial prefrontal cortex that is critical for subsequent retrieval of the extinction memory. Understanding the mechanisms that underlie this extinction-related plasticity could help in the treatment of anxiety disorders. By infusing BDNF (brain-derived neurotrophic factor) into the infralimbic cortex, Peters et al. caused the extinction of conditioned fear, even without an extinction trial. In fact, BDNF infusion seemed to act as if an extinction training session had been given. Thus, the hippocampus is a likely source of the BDNF input to the infralimbic cortex, and individual differences in extinction memory may reflect variations in hippocampal BDNF content.. J. Peters, L. M. Dieppa-Perea, L. M. Melendez, G. J. Quirk, Induction of fear extinction with hippocampal-infralimbic BDNF. Science 328, 1288-1290 (2010). [Abstract] [Full Text]. ...

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. ...

Infusing brain-derived neurotrophic factor (BDNF) into the infralimbic (IL) prefrontal cortex is capable of inducing extinction. Little is known, however, about the circuits mediating BDNF effects on extinction or the extent to which extinction requires BDNF in IL. Using local pharmacological infusion of BDNF protein, or an antibody against BDNF, we found that BDNF in the IL, but not prelimbic (PL) prefrontal cortex, is both necessary and sufficient for fear extinction. Furthermore, we report that BDNF in IL can induce extinction of older fear memories (14 days) as well as recent fear memories (1 day). Using immunocytochemistry, we show that BDNF is increased in the ventral hippocampus (vHPC), but not IL or PL, following extinction training. Finally, we observed that infusing BDNF into the vHPC increased the firing rate of IL, but not PL neurons in fear conditioned rats. These findings indicate that an extinction-induced increase in BDNF within the vHPC enhances excitability in IL targets, ...

We examined the role of PKA in extinction of context-evoked fear using two distinct yet complementary transgenic approaches that allowed us to reduce PKA activity selectively in forebrain neurons. Both approaches revealed a facilitative effect of PKA inhibition on the development of extinction. Such an effect was observed both across extinction sessions with daily brief exposures (3 min) to the conditioning context in the absence of shock (Fig. 1A), as well as within extinction sessions during daily long exposures (24 min) to the context in the absence of shock (Fig. 2, 5B). These findings suggest that PKA inhibition affects both the short-term development of extinction within a session as well as the retention of extinction across sessions, depending on the duration of the extinction session. Spontaneous recovery was observed in both cases, either the next day, which occurred with long extinction sessions (Figs. 2, 5B), or 21 d later, which occurred with short extinction sessions (Fig. 1B). Our ...

Extinctions are caused by environmental and ecological change but are recognized and measured in the fossil record by the disappearance of clades or lineages. If the ecological preferences of lineages or taxa are weakly congruent with their phylogenetic relationships, even large ecological perturbations are unlikely to drive major clades extinct because the factors that eliminate some species are unlikely to affect close relatives with different ecological preferences. In contrast, if phylogenetic relatedness and ecological preferences are congruent, then ecological perturbations can more easily cause extinctions of large clades. In order to quantify this effect, we used a computer model to simulate the diversification and extinction of clades based on ecological criteria. By varying the parameters of the model, we explored (1) the relationship between the extinction probability for a clade of a given size (number of terminals) and the overall intensity of extinction (the proportion of the ...

Extinction of Pavlovian conditioning is a complex process that involves brain regions such as the medial prefrontal cortex (mPFC), the amygdala and the locus coeruleus. In particular, noradrenaline (NA) coming from the locus coeruleus has been recently shown to play a different role in two subregions of the mPFC, the prelimbic (PL) and the infralimbic (IL) regions. How these regions interact in conditioning and subsequent extinction is an open issue. We studied these processes using two approaches: computational modelling and NA manipulation in a conditioned place preference paradigm (CPP) in mice. In the computational model, NA in PL and IL causes inputs arriving to these regions to be amplified, thus allowing them to modulate learning processes in amygdala. The model reproduces results from studies involving depletion of NA from PL, IL, or both in CPP. In addition, we simulated new experiments of NA manipulations in mPFC, making predictions on the possible results. We searched the parameters ...

Life on Earth has endured five major mass extinctions, known as the Big Five. We know about these past events thanks to fossils: During mass extinctions, many species evident in the rock record disappeared from Earth relatively quickly. Today, human alteration of the environment is driving what scientists call the sixth great extinction, but according to new research, the current extinction differs from the Big Five in a key way: Much of the life facing extermination today will likely not be preserved as fossils. This means that, to future paleontologists looking at the rock record from today, the sixth extinction might not appear to have been such a major event.. ...

TY - JOUR. T1 - Noise-induced switching and extinction in systems with delay. AU - Schwartz, Ira B.. AU - Billings, Lora. AU - Carr, Thomas W.. AU - Dykman, M. I.. PY - 2015/1/26. Y1 - 2015/1/26. N2 - We consider the rates of noise-induced switching between the stable states of dissipative dynamical systems with delay and also the rates of noise-induced extinction, where such systems model population dynamics. We study a class of systems where the evolution depends on the dynamical variables at a preceding time with a fixed time delay, which we call hard delay. For weak noise, the rates of interattractor switching and extinction are exponentially small. Finding these rates to logarithmic accuracy is reduced to variational problems. The solutions of the variational problems give the most probable paths followed in switching or extinction. We show that the equations for the most probable paths are acausal and formulate the appropriate boundary conditions. Explicit results are obtained for small ...

There seems to have been a surge in ultraviolet radiation during the Permian extinction 252 million years ago, and it might have left plants infertile rather than kill them

Aerosol radiative effects and thermodynamic responses over South Asia are examined with the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) for March 2012. Model results of aerosol optical depths (AODs) and extinction profiles are analyzed and compared to satellite retrievals and two ground-based lidars located in northern India. The WRF-Chem model is found to heavily underestimate the AOD during the simulated pre-monsoon month and about 83 % of the models low bias is due to aerosol extinctions below ~2 km. Doubling the calculated aerosol extinctions below 850 hPa generates much better agreement with the observed AOD and extinction profiles averaged over South Asia. To separate the effect of absorption and scattering properties, two runs were conducted: in one run (Case I), the calculated scattering and absorption coefficients were increased proportionally, while in the second run (Case II) only the calculated aerosol scattering coefficient was increased. With the same ...

Theoretical considerations suggest that extinction in dispersal-limited populations is necessarily a threshold-like process that is analogous to a critical phase transition in physics. We use this analogy to find robust, common features in the dynamics of extinctions, and suggest early warning signals which may indicate that a population is endangered. As the critical threshold of extinction is approached, the population spontaneously fragments into discrete subpopulations and, consequently, density regulation fails. The population size declines and its spatial variance diverges according to scaling laws. Therefore, we can make robust predictions exactly in the range where prognosis is vital, on the verge of extinction.. ...

The extinction of one carnivore species can trigger the demise of fellow predators, conservation biologists at the University of Exeter have confirmed.

Unlike conservation biology, which formed from an amalgam of ecological, environmental and evolutionary strands into a coherent field of research in the 1980s, the study of species losses has remained rather dispersed, despite some concerted efforts to banner it under extinction biology (e.g. [4]). Giving extinction a unifying framework is both intellectually appealing and practically useful. For instance, understanding its general mechanisms is essential for predicting the impact of future stressors, such as anthropogenic habitat loss, climate change, invasive species or exploitation [5,6], on threatened biota. Indeed, deriving generalizations (e.g. identifying functional and life-history traits that predispose species to extinction due to specific causes [7]) is critical in a crisis discipline where data are sparse, many uncertainties remain, and yet decisions are urgent [8].. Extinction biology is the science of developing theoretical, experimental and historical tests of the mechanisms ...

Zoals je weet pakken we het bij Extinction Rebellion anders aan. We gaan voorbij aan klimaatmarsen en petities, en bouwen een massabeweging die het tij kan keren. En in deze bijeenkomst leer je hoe je op een manier die bij jou past mee kan rebelleren!. De bijeenkomst is online via zoom, tegelijkertijd in zowel Nederlands als Engels. De link voor de Nederlandse sessie. DEEL 1: Het eerste uur hebben we het over de klimaat- en ecologische crisis, met uiteraard ruimte voor interactie. Het is erger dan je denkt, maar geen zorgen: je hoort ook over Extinction Rebellion, en hoe wij denken het verschil te kunnen maken.. DEEL 2: Bouw mee aan XR! In deze sessie leer je hoe jij je met een paar uurtjes per week in kan zetten op een manier die bij je past. Als manusje van alles bij je lokale groep, of juist als specialist bij een nationale kring: van juridische of mentale ondersteuning tot het organiseren of promoten van acties en evenementen, en nog véél meer.. Ben je alleen nieuwsgierig naar XR? Dan kan ...

Dear all, I would like to know about extinction coefficients for equine seric Fab, F(ab)2. Did you find it before? How did you get it? Thank you in advance Susan ...

Some of the eco-warriors at the Harvil road and Denham camps in Colne Valley near Uxbridge invited Extinction Rebellion to join them at the protest sites last year, and HS2 Rebellion was the name that was eventually chosen to be used by the new recruits. Unfortunately a power struggle developed fairly soon, with HS2 Rebellion apparently insisting that they controlled some kind of hierarchy and were in fact the leaders of the climate movement, and all the protesters were obliged to take orders from them.. Extinction Rebellion released a statement about how HS2 Rebellion was becoming the umbrella organisation for all the protection camps and they listed their criteria and values which they claimed all the activists had to agree to and abide by. This was regardless of the fact that the eco-warriors had originally started the camps with the Green Party four years before XR came along to attempt to take them over and control them ...

HENRIQUEZ, Carola and LISSI, Eduardo. EVALUATION OF THE EXTINCTION COEFFICIENT OF THE ABTS DERIVED RADICAL CATION. Bol. Soc. Chil. Quím. [online]. 2002, vol.47, n.4, pp.363-366. ISSN 0366-1644. http://dx.doi.org/10.4067/S0366-16442002000400029.. The exact knowledge of the value of the extinction coefficient of the ABTS derived radical is necessary for its quantitative use in the evaluation of the antioxidant capacity of pure compounds and/or complex mixtures. We have performed experiments in order to stablish its lower and upper limits of its value. The limits obtained, 1.0 x 104 M-1 cm-1 £ e 734 £ 1.6 x 104 M-1 cm-1 are fully compatible with previously reported data. However, the use of these values leads to large stoichiometric coefficients for the reaction of these radicals with simple substrates, such as monophenols or tryptophan.. Keywords : ABTS; extintion coefficient; antioxidants evaluation. ...

This Biology Factsheet summarises: • Human population and extinctions. • Factors that may decrease the chances of a species becoming extinct. • Reasons for trying to prevent extinction.

Its well known that Earths most severe mass extinction occurred about 250 million years ago. Whats not well known is the specific time when the extinctions occurred. A team of researchers from North America and China have ...

I was interviewed today by Peter Melton, on Extinction Radio, last Wednesday, and is also posted under Media. The entire show which also includes no less than Carolyn Baker, and Guy McPherson is shared here, and those with less time who might want to or need to hear my brief, can simply click to the queue…

Painstaking analyses of fossils from the Permian extinction, 252 million years ago, are providing startling new clues to the behavior of modern marine life and its future.

Up to 1 million plant and animal species are on the verge of extinction, with devastating implications for human survival, according to a United Nations report released Monday.

Theyve been branded as anarchists and fringe-dwellers, but do Extinction Rebellion protesters really warrant such drastic reactions?

Animal extinction. Climate change. Illegal wildlife traffic. The problems are overwhelming, the scale enormous. But the solutions can start with you. #StartWith1Thing.

A frightening vision of the apocalypse, The Extinction Parade #5 is a terrifying read that doesnt hold back on its shocks and scares. With vampires on o

A new study by paleoecologist Margaret Fraiser at the University of Wisconsin, Milwaukee, offers an interesting new theory behind the cause of the Earths largest extinction: copious carbon-dioxide

A new study by paleoecologist Margaret Fraiser at the University of Wisconsin, Milwaukee, offers an interesting new theory behind the cause of the Earths largest extinction: copious carbon-dioxide

Pulling Teeth Extinction lyrics & video : a pleasant surprise but still unexpected the decision is made not to reject it plans have to change but it seems for the better creati...

The Federal Government would be lining up Australian wildlife for extinction if it rushes to devolve environmental approval powers to states, the Australian Conservation Foundation said today.

Extinction Fade To Brown by Tanya Anderson [Pdf] [ePub] Full Download Ebook. Quietly without most people noticing the population of giraffes in the wild has d

The book Imagining Extinction: The Cultural Meanings of Endangered Species, Ursula K. Heise is published by University of Chicago Press.

Behavioral persistence is required to reach a goal but may impede adaptations to changing environments. Given the well-documented effects of stress on learning and memory processes, we asked here whether stress affects the persistence of behavior. Participants were exposed to stress or a control con …

Daily News How Gaining and Losing Weight Affects the Body Millions of measurements from 23 people who consumed extra calories every day for a month reveal changes in proteins, metabolites, and gut microbiota that accompany shifts in body mass.. ...

Daily News How Gaining and Losing Weight Affects the Body Millions of measurements from 23 people who consumed extra calories every day for a month reveal changes in proteins, metabolites, and gut microbiota that accompany shifts in body mass.. ...

We all have read the unfortunate news about the prediction of human extinction by none other than Stephen Hawking. A trusted name in the scientific world. Extinction, how scary does it sound. Until a few years ago the word extinct was only used for animals species that we have lost. Which, by the way, are…

The International Whaling Commission (IWC) has taken up the cause of some of the worlds most critically endangered marine mammals by calling on governments to keep fishing nets out of their waters to prevent entanglement deaths.

Theres much evidence to sugges that the days of Macro Virus and Script Viruses are comming to an end. Happy? Well dont be, because whats developing instead is even worse... Behold the day of the…

emu, Fogel concluded.. Not everyone agrees that people forced the change in diet.. Large animals went extinct across the world between ...

The increase in population in England has made an impact on the environment. The rise from one million to more than fifty-one million in the past two millennia has resulted in the extinction of hundreds of native animals and plants ...

I thought that might be the case Wazza. FWIW, I think that most game in the burbs would be hunted to extinction in short order, once people got hungry enough. Its not something that I would rely on long term. I think of it more as a short-term emergency measure. Hunting in the burbs is illegal anyway, so that options off the table in any…[Read more]. ...

Social interaction is known to alter behavior and emotional responses to various events. It has been reported that when fear-conditioned animals are put in a fear extinction paradigm with non-fearful conspecifics (pair-exposure), freezing behavior decreases compared to a solitary situation. However, it remains unclear whether pair-exposure during fear extinction is persistently effective in reducing the freezing response. In this study, we examined whether the effect of pair-exposure could be persistently effective on cued and contextual fear extinction. The reduction of the fear compared to the solitary condition was transiently observed only in the cued fear extinction with no difference in the subsequent recall session. We also found that the correlation between corticosterone levels and freezing behavior during extinction was disrupted in the pair-exposure situation. These results suggest that pair-exposure reduces freezing behavior in cued fear extinction, although this fear response reduction is

Sex differences in learned fear expression and extinction involve the medial prefrontal cortex (mPFC). We recently demonstrated that enhanced learned fear expression during auditory fear extinction and its recall is linked to persistent theta activation in the prelimbic (PL) but not infralimbic (IL) cortex of female rats. Emerging evidence indicates that gamma oscillations in mPFC are also implicated in the expression and extinction of learned fear. Therefore we re-examined our in vivo electrophysiology data and found that females showed persistent PL gamma activation during extinction and a failure of IL gamma activation during extinction recall. Altered prefrontal gamma oscillations thus accompany sex differences in learned fear expression and its extinction. These findings are relevant for understanding the neural basis of post-traumatic stress disorder, which is more prevalent in women and involves impaired extinction and mPFC dysfunction.. ...

Memories are not always worth keeping. People who suffer from post-traumatic stress disorder, for example, wrestle to suppress thoughts and feelings that take a heavy emotional toll. Unfortunately, it is not always possible to purge bad memories, but as scientists begin to understand the biology behind memory extinction, there is a glimmer of hope that they might find a therapeutic approach that helps. In this weeks Nature Neuroscience online, researchers led by Li-Huei Tsai at MIT reveal one aspect of memory extinction that may be amenable to manipulation. They report that in mice, contextual fear extinction is impaired by Cdk5, a kinase best known for its role in the developing nervous system. Cdk5 has also been implicated in the pathology of Alzheimer disease and other neurodegenerative disorders (see ARF related news story).. Memory extinction is often measured in mice using a fear conditioning paradigm, where animals learn to associate a condition, such as a specific cage or environment, ...

Little is known about the neural correlates of fear learning in adolescents, a population at increased risk for anxiety disorders. Healthy adolescents (mean age 16.26) and adults (mean age 29.85) completed a fear learning paradigm across two stages during functional magnetic resonance imaging (fMRI). Stage 1 involved conditioning and extinction, and stage 2 involved extinction recall, re-conditioning, followed by re-extinction. During extinction recall, we observed a higher skin conductance response to the CS+ relative to CS- in adolescents compared to adults, which was accompanied by a reduction in dorsolateral prefrontal cortex (dlPFC) activity. Relative to adults, adolescents also had significantly reduced activation in the ventromedial PFC, dlPFC, posterior cingulate cortex (PCC), and temporoparietal junction (TPJ) during extinction recall compared to late extinction. Age differences in PCC activation between late extinction and late conditioning were also observed. These results show for ...

Fingerprint Dive into the research topics of Functional deficit in hippocampal activity during fear extinction recall in the single prolonged-stress model of PTSD in male rats. Together they form a unique fingerprint. ...

ABSTRACT. The end-Permian extinction event is regarded as the most severe of the five major extinction events in the history of life. Recent work in the Karoo Basin of South Africa suggests that the extinctions at the Permo-Triassic boundary (PTB) may have been followed by a second pulse of extinctions, one that claimed the few species that crossed the PTB and thus survived the first extinction pulse. We report here a new specimen of the procolophonoid reptile, Sauropareion anoplus, which was known heretofore only from a single specimen from Lower Triassic strata of the Palingkloof Member, Balfour Formation. The new specimen comes from the lower part of the overlying Katberg Formation and serves as the last appearance datum for the stratigraphic range of S. anoplus. It indicates that S. anoplus survived the second pulse of PTB extinctions and reinforces the hypothesis that procolophonoid evolution was not seriously perturbed by extinctions that mark the beginning of the Triassic Period.. ...

The molecular mechanisms underlying drug extinction remain largely unknown, although a role for medial prefrontal cortex (mPFC) glutamate neurons has been suggested. Considering that the mPFC sends glutamate efferents to the ventral tegmental area (VTA), we tested whether the VTA is involved in methamphetamine (METH) extinction via conditioned place preference (CPP). Among various METH-CPP stages, we found that the amount of phosphoGluR1/Ser845 increased in the VTA at behavioral extinction, but not the acquisition or withdrawal stage. Via surface biotinylation, we found that levels of membrane GluR1 were significantly increased during METH-CPP extinction, while no change was observed at the acquisition stage. Specifically, the number of dendritic spines in the VTA was increased at behavioral extinction, but not during acquisition. To validate the role of the mPFC in METH-CPP extinction, we lesioned the mPFC. Ibotenic acid lesioning of the mPFC did not affect METH-CPP acquisition,

It is generally believed that fear extinction is a form of new learning that inhibits rather than erases previously acquired fear memories. Although this view has gained much support from behavioural and electrophysiological studies, the hypothesis that extinction causes the partial erasure of fear …

The efficacy of many proposed kill mechanisms, such as synchronous sea surface and atmospheric temperature increase, rapid rise in pCO2, and flooding of shelf areas with anoxic and euxinic waters, depends on rate of change and on precisely when they occur relative to the onset of extinction (9, 34, 35). For example, it is crucial to know whether the ∼10 °C increase in sea surface temperature close to the extinction interval slightly predates or postdates the onset of the mass extinction (9, 33) (Fig. S1). More detailed study of the relationship between temperature increase and extinction is needed from less condensed sections than Meishan to evaluate whether temperature leads or lags the extinction and the relationship between temperature rise and changes in the carbonate carbon isotopic record. Using the maximum extinction duration of ∼60 ka, this suggests an ∼1 °C increase per 6,000 y, comparable to the rate and magnitude of the increase at the Paleocene-Eocene Thermal Maximum (PETM) ...

After fear conditioning, presenting the conditioned stimulus (CS) alone yields a context-specific extinction memory; fear is suppressed in the extinction context, but renews in any other context. The context-dependence of extinction is mediated by a brain circuit consisting of the hippocampus, prefrontal cortex (PFC) and amygdala. In the present work, we sought to determine at what level of this circuit context-dependent representations of the CS emerge. To explore this question, we used cellular compartment analysis of temporal activity by fluorescent in situ hybridization (catFISH). This method exploits the intracellular expression profile of the immediate early gene (IEG), Arc, to visualize neuronal activation patterns to two different behavioral experiences. Rats were fear conditioned in one context and extinguished in another; 24 h later, they were sequentially exposed to the CS in the extinction context and another context. Control rats were also tested in each context, but were never ...

Present -day risk assessment would have predicted the extinction of the passenger pigeon (Ectopistes migratorius). Stanton, J,C., 2014, Present -day risk assessment would have predicted the extinction of the passenger pigeon (Ectopistes migratorius). Biological Conservation, v 180, p 11-20, doi:10.1016/j.biocon.2014.09.023. Abstract. The precipitous decline and extinction of the passenger pigeon one century ago helped galvanize implementation of national policies and international cooperation on wildlife management. Having a clear understanding of past conservation failures will aid in preventing future unanticipated extinctions. Simulations from a population model developed for this species indicate that while habitat loss contributed to decline, the main cause of the extinction was an unregulated commercial harvest. Hindcast application of the IUCNs Red Listing criteria to modeled population trajectories show that the species would have been listed as threatened for decades prior to ...

WONG, Heidi and WANG, Steve C., Mathematics and Statistics, Swarthmore College, 500 College Ave, Swarthmore, PA 19081, [email protected] In the past few decades, there has been much interest in determining whether mass extinction events were simultaneous or gradual. This task, however, is complicated by the incompleteness of the fossil record. Using statistical methods, a number of authors have accounted for such Signor-Lipps effects in testing whether a pattern of fossil occurrences is consistent with a simultaneous extinction. In such tests, the null hypothesis is typically that the extinction was simultaneous, with the alternative hypothesis being that the extinction was gradual. If the record of fossil occurrences does not strongly contradict the null hypothesis, we conclude the extinction could have been simultaneous. However, even if the null hypothesis is not rejected, it is incorrect to infer that the null hypothesis must therefore be true. In fact, any set of fossil occurrences ...

Urban also made the surprising discovery that the varying research methods employed didnt matter - the different papers all pointed towards similar estimates of extinction risk. Studies that built statistical models that correlate environmental factors to the distribution and abundance of species, produced on average the same results as mechanistic or process-based models that simulate populations of species. Very different techniques were producing the same magnitudes of extinction risk.. However, there were some key factors in Urbans analysis that were associated with large uncertainty. The biggest differences in extinction risk were associated with different carbon emissions scenarios. This will be largely up to us to determine - how much of the existing reserves of coal, oil and gas are we willing to burn off? The second most important factor was the extinction debt - the unavoidable extinction of species - as a consequence of habitat loss.. If a species of tree frog can only reproduce in ...

Studies of species-area curves and of the spatial correlation of biogeographic ranges with climatic variables may allow some crude prediction of amount of extinction over large regions in the face of major environmental change. However, these approaches tell little about the proximate causes of species loss. The contention that failure of metapopulation dynamics is at the root of many species extinctions is so far not borne out by observed rates of inter-population movement. Rather, most species that have a metapopulation structure seem to have central source populations and peripheral sink populations. Much of the extinction recorded in the ecological literature is probably of such peripheral populations and their loss has little to do with species extinctions. The disappearance of central, source populations is more important but its causes are not well documented. Habitat loss is the single greatest ultimate cause of current extinction. However, disappearance of the very last individuals of ...

Extinction risk in vertebrates has been linked to large body size, but this putative relationship has only been explored for select taxa, with variable results. Using a newly assembled and taxonomically expansive database, we analyzed the relationships between extinction risk and body mass (27,647 species) and between extinction risk and range size (21,294 species) for vertebrates across six main classes. We found that the probability of being threatened was positively and significantly related to body mass for birds, cartilaginous fishes, and mammals. Bimodal relationships were evident for amphibians, reptiles, and bony fishes. Most importantly, a bimodal relationship was found across all vertebrates such that extinction risk changes around a body mass breakpoint of 0.035 kg, indicating that the lightest and heaviest vertebrates have elevated extinction risk. We also found range size to be an important predictor of the probability of being threatened, with strong negative relationships across ...

Stress modulates instrumental action in favor of habit processes that encode the association between a response and preceding stimuli and at the expense of goal-directed processes that learn the association between an action and the motivational value of the outcome. Here, we asked whether this stress-induced shift from goal-directed to habit action is dependent on noradrenergic activation and may therefore be blocked by a β-adrenoceptor antagonist. To this end, healthy men and women were administered a placebo or the β-adrenoceptor antagonist propranolol before they underwent a stress or a control procedure. Shortly after the stress or control procedure, participants were trained in two instrumental actions that led to two distinct food outcomes. After training, one of the food outcomes was selectively devalued by feeding participants to satiety with that food. A subsequent extinction test indicated whether instrumental behavior was goal-directed or habitual. As expected, stress after placebo ...

The molecular mechanism underlying the extinction of lipoprotein lipase (LPL) expression in rat liver during development was investigated. A mouse (BWTG3) and a rat (7777) hepatoma, both of which exhibit characteristics of fetal hepatocytes, were found to contain LPL mRNA, whereas the more differentiated human (Hep G2 and Hep 3B) or rat (Fa32) hepatoma cell lines did not. Somatic cell hybrids between LPL-producing hepatoma cells and non-LPL-producing cells, such as adult rat hepatocytes or fibroblasts, exhibited extinction of LPL gene expression. Assay of expression of nested deletions in the 5 regulatory sequences of the LPL gene in the Hep G2 cell line and in BWTG3 cells localized sequences involved in the suppression of LPL production to a region between -591 and -288 relative to the transcription initiation site. A site with sequence homology to a glucocorticoid responsive element (GRE) was shown not to play an important role in the extinction process. A novel transcription factor, termed RF-1-LPL,

A global analysis published in Nature Ecology and Evolution collates all plant extinction records documented from across the world. The unique dataset shows how many plant species have gone extinct in the last 250 years.. Dr Bjorn Robroek, Lecturer in Ecology, University of Southampton, said:. This is an interesting piece of work. The science seems sound and thorough. The finding that extinction rates are highest in biodiversity hotspots that are at risk due to land-use change is alarming and echoes the message put forward by the recent IPBES report (https://www.ipbes.net) that current losses in suitable habitat should be high on the political agenda. Indeed, extinction rates are likely still underestimated and more effort needs to go in getting good estimates about extinction rates in underrepresented ecosystems (not only biodiverse systems as the authors state) and plant groups, including algae. That the authors found no clear pattern in evolutionary-closely-related plants regarding ...

The number of extinct animals in 2017 is on the rise. The continuation and rapid speed of extinction and threat to extinction are causing the biodiversity loss which has negative impacts on the balance and whole ecosystems globally.

Evolution, mass extinctions and mass speciations are the result of ionizing radiation, magnetic field reversals, and other factors of an activated planet. The resulting rearrangment of genetic material leads to new species and the extinction of the older species, and this is why mass extinctions are followed by mass speciations.

We demonstrate that more branches from the tree-of-life are pruned when extinction is phylogenetically non-random, but that the loss of their summed lengths is no greater than expected by chance. Furthermore, in some cases (e.g. Artiodactyla), non-random extinction can reduce the loss of branch lengths, presumably because threatened species tend to cluster within young, species-rich clades, while the number of branches being pruned may still be greater than random expectations. We suggest that number of branches, rather than branch lengths, might be important if trait variation accumulates in bursts at speciation events (represented by the nodes in the phylogenetic tree), as would be expected under a model of punctuated equilibrium [26]. If evolution follows a speciational model (and this may be the case for body size in mammals; [27]), short branches separating rapidly diverging lineages might capture as much feature diversity as longer branches in more slowly diversifying clades, although ...

It is important to emphasize that the reduction in robustness caused by the inclusion of parasites did not result from parasite-induced extinctions of hosts (an outcome not possible in our topological approach). Instead, the decrease in robustness was due to the higher sensitivity of parasites to secondary extinction. This finding was only possible when considering that each life stage in a trematode life cycle has a potentially different set of hosts. Had we simply lumped all life stages, the trematodes would have appeared to have had a wide host range and to have been relatively invulnerable to secondary extinction.. Empirical studies in this system reveal more subtle dependencies of parasites on the host community. For instance, a decrease in the diversity and abundance of birds at a particular site directly decreases the diversity and abundance of trematodes using C. californica (Hechinger & Lafferty 2005). Furthermore, the trematode assemblage at a particular location depends on the ...

Jay Williams1 tells about an old woman who was living out the last days of her life. Surrounded by white walls, upon a white bed, in care of doctors and nurses, this dark-skinned relict fought off death with all her primitive vitality. She rebuked her attendants and intermittently broke forth in song and chants. But inevitably she collapsed onto her pillows and whispered, Bury me behind the mountains. And so she died, but her skeleton was placed instead in a city museum, for she was the last of her kin. With her passing, the Tasmanian people became extinct.. Extinction is like that. It is the absolute terminus for a formerly recognized group of organisms. When mortality exceeds natality for a sufficient time to bring the total number of individuals of a species to zero or one (for those organisms which reproduce sexually), then extinction is pronounced.2. Since life began, many organisms have been lost from the biosphere through extinction. Some people feel that this is a normal expectation of ...

A new model of delayed species loss (extinction debt) within isolated communities is applied to a large data set of terrestrial vertebrate assemblages (n = 188) occupying habitat fragments or islands varying greatly in size and age. The model encapsulates previous approaches based on diversity-dependent (DD) extinction rates while allowing for a more flexible treatment of temporal dynamics. Three important results emerge. First, species loss rate slows down with the age of the isolate, a strong and general pattern largely unnoticed so far. Secondly, while being good candidates in the light of previous works, DD models fail to account for this pattern, a result that necessitates a search for other mechanisms. Thirdly, a simple diversity-independent model based on area (converted into population size) and age explains 97% of the variability in species loss rate and appears to be a promising predictive tool to handle extinction debt following habitat loss ...

Our study was inspired by the observation that young individuals suffering from psychiatric diseases such as PTSD have an increased risk to develop AD as they age (Yaffe et al, 2010; Burri et al, 2013; Weiner et al, 2013). We reasoned that one possible way to begin elucidating this phenomenon would be to select genes that have been implicated with age‐associative memory decline and to test whether these genes may also play a role in the development of PTSD‐like phenotypes, which we analyzed in mice via fear extinction as a commonly used and robust paradigm. Nevertheless, we like to reiterate that results from animal models of neuropsychiatric diseases have to be interpreted with care, and while impaired fear extinction in rodents may point to the mechanisms that underlie increased susceptibility for PTSD, it does not fully recapitulate the phenotypes observed in PTSD patients. We observed that deficits in fear extinction precede memory decline in Fmn2−/− mice, and moreover, Fmn2 ...

A new report has urged the federal government to take action, after it was revealed Australia has lost more mammals to extinction than any other country.

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...Scientists have uncovered a lot about the Earths greatest extinction ... No one had ever looked to see if mercury was a potential culprit. Thi...Dr. Benoit Beauchamp professor of geology at the University of Calgar... Geologists including myself should be taking notes and taking anothe...,Earths,massive,extinction:,The,story,gets,worse,biological,biology news articles,biology news today,latest biology news,current biology news,biology newsletters

Transformers: Age of Extinction is the fourth film in director Michael Bays global blockbuster franchise. Mark Wahlberg, Stanley Tucci, Li Bingbing , Kelsey Grammer, Sophia Myles, T. J. Miller, Nicola Peltz, Jack Reynor and Titus Welliver star. The film begins after an epic battle that left a great city torn, but with the world saved. As humanity picks up the pieces, a shadowy group reveals itself in an attempt to control the direction of history… while an ancient, powerful new menace sets Earth in its crosshairs. With help from a new cast of humans, Optimus Prime (voiced by Peter Cullen) and the Autobots rise to meet their most fearsome challenge yet. In an incredible adventure, they are swept up in a war of good and evil, ultimately leading to a climactic battle across the world. Transformers: Age of Extinction is in theaters 06.27.14

You probably already know the planet is experiencing an extinction crisis; scientists estimate well lose up to 50 percent of current species during the next 20 years. But did you know theres also an extinction crisis of gut bacteria happening among civilized humans?The modern diet, which is high in processed foods, meats and sugars but…

As the need increases for sound estimates of impending rates of animal and plant species extinction, scientists must have a firm grounding in the qualitative and quantitative methods required to make the best possible predictions. Extinction Rates offers the most wide-ranging and practical introduction to those methods available.

To prevent extinction, banks have to stop funding it. - Portfolio Earth Thats according to Bankrolling Extinction, a new report published Wednesday by Portfolio Earth, an initiative seeking to challenge the financial industrys role in ecological devastation. The report shows Big Banks lent ...

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Otto: Any age.. Stage setting: A closed space with leaks in the ceiling. The rear part of a car with a television. Kitchen with a gas tap.. Summary: A married couple lives a strange and routine enclosure. The son comes to realize his revenge upon them. The mother plays out a different relationship in her head.. Type of theater: An ironic tragic-comedy on family and enclosure.. Aa puzzle halfway between amusement, playfulness and criticism.. Hey, do you know a more sinister institution than the family?. It combines the caustic with the intimate, the desperate with the comic.. The family has humor in it, it will soon disappear.. The humor conditions the style whose undercurrent hides a notable violence.. An amusing and efficient play.. The four black (or white) beasts of my inspiration run loose.. The time has come to eradicate their common denominator: monotheism.. I am fed up with the world.. Productions: ...

Croatian marine biologists are struggling to save the largest Mediterranean clam from extinction after a precipitious fall in numbers which they say was probably caused by a deadly pathogen.

Whether you are in the mood for some catfish from Oleans, crap legs from Red Lobster or some good old fashion sushi, seafood seems to be that type of food that appears to always be around; there are four oceans and numerous lakes and rivers.. But, have we bitten off more than we can chew?. I know 2048 may seem like a long way down the line, but for the future generations, seafood may become a rare delicacy.According to an article posed on http://cnn.com, crab cakes, swordfish, clambakes and even fish sticks could soon be considered a thing of the past. Some ecologists believe that if the current trends of over fishing and pollution continue, almost all seafood will face extinction by 2048. The aforementioned seafood dishes could be little more than a fond memory in a few decades. Whether we looked at tide pools or studies over the entire worlds ocean, we saw the same picture emerging. In losing species we lose the productivity and stability of entire ecosystems, said lead author of an ...

Dawn of Extinction had planned to start this 2021 with the release of a new EP that would be a continuation of their successful Welcome to the New Century. However, the pandemic we are all suffering has taken this and many other great plans with it, causing the deadlines to be lengthened and the dates postponed.. But the group did not want to leave their fans without any new material, and for that reason they have set to work to launch Lost Paradise. This single, which will not be included in any release, shows a new face of the more relaxed and intimate group, but equally direct. A song that is out of the ordinary patterns to which we are accustomed and that will surely put them on the radar of many new listeners. ...

Evidence trapped in 250-million-year-old sediments may help researchers pin the ultimate blame for the massive extinctions that occurred then on the impact of an extraterrestrial object about 9 kilometers across.

Ancient teeth from Italy suggest the arrival of modern humans in Western Europe coincided with the demise of Neanderthals there, suggesting man played a role in this extinction.

Environmental stress has played a major role in the evolution of living organisms (Hoffman AA, Parsons PA. 1991. Evolutionary genetics and environmental stress. Oxford: Oxford University Press; Parsons PA. 2005. Environments and evolution: interactions between stress, resource inadequacy, and energetic efficiency. Biol Rev Camb Philos Soc. 80:589 610). This is reflected by the massive and background extinctions in evolutionary time (Nevo E. 1995a. Evolution and extinction. Encyclopedia of Environmental Biology. New York: Academic Press, Inc. 1:717 745). The interaction between organism and environment is central in evolution. Extinction ensues when organisms fail to change and adapt to the constantly altering abiotic and biotic stressful environmental changes as documented in the fossil record. Extreme environmental stress causes extinction but also leads to evolutionary change and the origination of new species adapted to new environments. I will discuss a few of these global, regional, and ...

By Peter Moyle In case you hadnt noticed, one of Californias most spectacular fish is leaving us. The coho salmon, silvery favorites of fishermen and essential components of our coastal rainforest ecosystems, are headed for extinction in the state. This projection was made abundantly clear, at least to me, in a recent (August 16) State…

Human impact can explain ninety-six percent of all mammal species extinctions of the last hundred thousand years, according to a new study published in the scientific journal Science Advances.

As the Extinction Rebellion protesters target the London Underground, there is already chaos on the tubes for commuters this morning.

The Evolution and Extinction of the Dinosaurs by David E. Fastovsky, 9780521811729, available at Book Depository with free delivery worldwide.

Read independent reviews on OPUS - Ultrasonic extinction sensor for particle characterisation in highly concentrated suspensions and emulsions for process or laboratory application from below 0.1 µm to 3,000 µm from Sympatec GmbH on SelectScience