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Extinction

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https://www.readbyqxmd.com/read/28214541/think-twice-it%C3%AC-s-all-right-long-lasting-effects-of-disrupted-reconsolidation-on-brain-and-behavior-in-human-long-term-fear
#1
Johannes Björkstrand, Thomas Agren, Fredrik Åhs, Andreas Frick, Elna-Marie Larsson, Olof Hjorth, Tomas Furmark, Mats Fredrikson
Memories can be modified when recalled. Experimental fear conditioning studies support that amygdala-localized fear memories are attenuated when reconsolidation is disrupted through extinction training immediately following memory activation. Recently, using functional brain imaging in individuals with lifelong spider fears, we demonstrated that fear memory activation followed by repeated exposure to feared cues after 10minutes, thereby disrupting reconsolidation, attenuated activity in the amygdala during later re-exposure, and also facilitated approach behavior to feared cues...
February 15, 2017: Behavioural Brain Research
https://www.readbyqxmd.com/read/28213477/soft-selective-sweeps-in-evolutionary-rescue
#2
Benjamin A Wilson, Pleuni S Pennings, Dmitri A Petrov
Evolutionary rescue occurs when a population that is declining in size because of an environmental change is rescued from extinction by genetic adaptation. Evolutionary rescue is an important phenomenon at the intersection of ecology and population genetics, and the study of evolutionary rescue is critical to understanding processes ranging from species conservation to the evolution of drug and pesticide resistance. While most population genetic models of evolutionary rescue focus on estimating the probability of rescue, we focus on whether one or more adaptive lineages contribute to evolutionary rescue...
February 17, 2017: Genetics
https://www.readbyqxmd.com/read/28213443/changes-in-appetitive-associative-strength-modulates-nucleus-accumbens-but-not-orbitofrontal-cortex-neuronal-ensemble-excitability
#3
Joseph Ziminski, Sabine Hessler, Gabriella Margetts-Smith, Meike C Sieburg, Hans S Crombag, Eisuke Koya
Cues that predict the availability of food rewards influence motivational states and elicit food-seeking behaviors. If a cue no longer predicts food availability, animals may adapt accordingly by inhibiting food seeking responses. Sparsely activated sets of neurons, coined neuronal ensembles, have been shown to encode the strength of reward-cue associations. While alterations in intrinsic excitability have been shown to underlie many learning and memory processes, little is known about these properties specifically on cue-activated neuronal ensembles...
February 17, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28213347/a-new-cheirolepidiaceae-coniferales-from-the-early-jurassic-of-patagonia-argentina-reconciling-the-records-of-impression-and-permineralized-fossils
#4
Ignacio Escapa, Andrew Leslie
PREMISE OF THE STUDY: Plants preserved in different fossil modes provide complementary data concerning the paleobiology and evolutionary relationships among plant groups. New material from the Early Jurassic of Patagonia shows the importance of combining these sources of information, as we describe the first compression/impression fossils of Pararaucaria, a genus of the extinct conifer family Cheirolepidiaceae previously known from permineralized fossils. These fossils extend the temporal range of this genus and may allow its wider recognition in the fossil record...
February 17, 2017: American Journal of Botany
https://www.readbyqxmd.com/read/28212786/interplay-between-microbial-trait-dynamics-and-population-dynamics-revealed-by-the-combination-of-laboratory-experiment-and-computational-approaches
#5
Kenta Suzuki, Yuji Yamauchi, Takehito Yoshida
Filament formation is a common bacterial defense mechanism and possibly has a broad impact on microbial community dynamics. In order to examine the impact of filament formation on population dynamics, we developed an experimental system with a filamentous bacterium Flectobacillus sp. MWH38 and a ciliate predator Tetrahymena pyriformis. In this system, the effective defense of Flectobacillus resulted in the extinction of Tetrahymena by allowing almost no population growth. The result of a kairomone experiment suggested the existence of chemical signals for filament formation...
February 14, 2017: Journal of Theoretical Biology
https://www.readbyqxmd.com/read/28211534/in-vitro-differentiation-of-fertile-sperm-from-cryopreserved-spermatogonia-of-the-endangered-endemic-cyprinid-honmoroko-gnathopogon-caerulescens
#6
Shogo Higaki, Manami Shimada, Kazuaki Kawamoto, Takaaki Todo, Toshihiro Kawasaki, Ikuo Tooyama, Yasuhiro Fujioka, Noriyoshi Sakai, Tatsuyuki Takada
Many endemic fish species are threatened with extinction. Conservation strategies and the restoration of endemic fish after extinction must therefore be investigated. Although sperm cryopreservation is indispensable for the conservation of endangered fishes, the limited number of mature fish and limited availability (volume and period) of sperm from small endemic fish hinders the optimization and practical use of this material. In this report, we demonstrate the in vitro differentiation of fertile sperm from cryopreserved spermatogonia of juveniles of the endangered small cyprinid honmoroko (Gnathopogon caerulescens), which is endemic to Lake Biwa in Japan...
February 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28211463/ecological-and-genetic-basis-of-metapopulation-persistence-of-the-glanville-fritillary-butterfly-in-fragmented-landscapes
#7
Ilkka Hanski, Torsti Schulz, Swee Chong Wong, Virpi Ahola, Annukka Ruokolainen, Sami P Ojanen
Ecologists are challenged to construct models of the biological consequences of habitat loss and fragmentation. Here, we use a metapopulation model to predict the distribution of the Glanville fritillary butterfly during 22 years across a large heterogeneous landscape with 4,415 small dry meadows. The majority (74%) of the 125 networks into which the meadows were clustered are below the extinction threshold for long-term persistence. Among the 33 networks above the threshold, spatial configuration and habitat quality rather than the pooled habitat area predict metapopulation size and persistence, but additionally allelic variation in a SNP in the gene Phosphoglucose isomerase (Pgi) explains 30% of variation in metapopulation size...
February 17, 2017: Nature Communications
https://www.readbyqxmd.com/read/28209076/an-ethnopharmacological-study-of-aromatic-uyghur-medicinal-plants-in-xinjiang-china
#8
Lu Zhao, Shuge Tian, E Wen, Halmuart Upur
CONTEXT: An ethnobotanical survey was completed in a remote village and surrounding country of Xinjiang, where most Uyghur medicinal plants could be collected. This work clarifies and increases ethnobotanical data. OBJECTIVES: We surveyed and organized aromatic medicinal plants that are commonly used in clinical settings to provide a significant reference for studying new medical activities. MATERIALS AND METHODS: In the survey, informants who have traditional knowledge on aromatic Uyghur medicinal plants were interviewed between March 2014 and September 2014...
December 2017: Pharmaceutical Biology
https://www.readbyqxmd.com/read/28208365/expansion-of-cooperatively-growing-populations-optimal-migration-rates-and-habitat-network-structures
#9
Kai-Cheng Yang, Zhi-Xi Wu, Petter Holme, Etsuko Nonaka
Range expansion of species is driven by the interactions among individual- and population-level processes and the spatial pattern of habitats. In this work we study how cooperatively growing populations spread on networks representing the skeleton of complex landscapes. By separating the slow and fast variables of the expansion process, we are able to give analytical predictions for the critical conditions that divide the dynamic behaviors into different phases (extinction, localized survival, and global expansion)...
January 2017: Physical Review. E
https://www.readbyqxmd.com/read/28207912/fear-conditioning-and-extinction-in-pediatric-obsessive-compulsive-disorder
#10
Daniel A Geller, Joseph F McGuire, Scott P Orr, Daniel S Pine, Jennifer C Britton, Brent J Small, Tanya K Murphy, Sabine Wilhelm, Eric A Storch
BACKGROUND: Fear acquisition and extinction are central constructs in the cognitive-behavioral model of obsessive-compulsive disorder (OCD), which underlies exposure-based cognitive-behavioral therapy. Youths with OCD may have impairments in fear acquisition and extinction that carry treatment implications. METHODS: Eighty youths (39 OCD, 41 healthy controls [HC]) completed clinical interviews, rating scales, and a differential conditioning task that included habituation, acquisition, and extinction phases...
February 2017: Annals of Clinical Psychiatry: Official Journal of the American Academy of Clinical Psychiatrists
https://www.readbyqxmd.com/read/28205643/optical-switching-using-transition-from-dipolar-to-charge-transfer-plasmon-modes-in-ge2sb2te5-bridged-metallodielectric-dimers
#11
Arash Ahmadivand, Burak Gerislioglu, Raju Sinha, Mustafa Karabiyik, Nezih Pala
Capacitive coupling and direct shuttling of charges in nanoscale plasmonic components across a dielectric spacer and through a conductive junction lead to excitation of significantly different dipolar and charge transfer plasmon (CTP) resonances, respectively. Here, we demonstrate the excitation of dipolar and CTP resonant modes in metallic nanodimers bridged by phase-change material (PCM) sections, material and electrical characteristics of which can be controlled by external stimuli. Ultrafast switching (in the range of a few nanoseconds) between amorphous and crystalline phases of the PCM section (here Ge2Sb2Te5 (GST)) allows for designing a tunable plasmonic switch for optical communication applications with significant modulation depth (up to 88%)...
February 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28205604/selectively-bred-rats-provide-a-unique-model-of-vulnerability-to-ptsd-like-behavior-and-respond-differentially-to-fgf2-augmentation-early-in-life
#12
Katherine E Prater, Elyse L Aurbach, Hanna K Larcinese, Taylor N Smith, Cortney A Turner, Peter Blandino, Stanley J Watson, Stephen Maren, Huda Akil
Individuals respond differently to traumatic experiences including their propensity to develop post-traumatic stress disorder (PTSD). Understanding individual differences in PTSD vulnerability will allow the development of improved prevention and treatment options. Here, we characterized fear conditioning and extinction in rats selectively bred for differences in their locomotor response to a novel environment. Selectively bred high responder (bHR) and low responder (bLR) male rats are known to differ in their emotional reactivity on a range of measures of spontaneous anxiety- and depressive-like behaviors...
February 16, 2017: Neuropsychopharmacology: Official Publication of the American College of Neuropsychopharmacology
https://www.readbyqxmd.com/read/28203151/cerebellar-tdcs-effects-on-conditioned-eyeblinks-using-different-electrode-placements-and-stimulation-protocols
#13
Linda Beyer, Giorgi Batsikadze, Dagmar Timmann, Marcus Gerwig
There is good evidence that the human cerebellum is involved in the acquisition and timing of classically conditioned eyeblink responses (CRs). Animal studies suggest that the cerebellum is also important in CR extinction and savings. Cerebellar transcranial direct current stimulation (tDCS) was reported to modulate CR acquisition and timing in a polarity dependent manner. To extent previous findings three experiments were conducted using standard delay eyeblink conditioning. In a between-group design, effects of tDCS were assessed with stimulation over the right cerebellar hemisphere ipsilaterally to the unconditioned stimulus (US)...
2017: Frontiers in Human Neuroscience
https://www.readbyqxmd.com/read/28202936/new-evidence-from-china-for-the-nature-of-the-pterosaur-evolutionary-transition
#14
Xiaoli Wang, Shunxing Jiang, Junqiang Zhang, Xin Cheng, Xuefeng Yu, Yameng Li, Guangjin Wei, Xiaolin Wang
Pterosaurs are extinct flying reptiles, the first vertebrates to achieve powered flight. Our understanding of the evolutionary transition between basal, predominantly long-tailed forms to derived short-tailed pterodactyloids remained poor until the discovery of Wukongopterus and Darwinopterus in western Liaoning, China. In this paper we report on a new genus and species, Douzhanopterus zhengi, that has a reduced tail, 173% the length of the humerus, and a reduced fifth pedal digit, whose first phalange is ca...
February 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28202907/calpain-1-deletion-impairs-mglur-dependent-ltd-and-fear-memory-extinction
#15
Guoqi Zhu, Victor Briz, Jeff Seinfeld, Yan Liu, Xiaoning Bi, Michel Baudry
Recent studies indicate that calpain-1 is required for the induction of long-term potentiation (LTP) elicited by theta-burst stimulation in field CA1 of hippocampus. Here we determined the contribution of calpain-1 in another type of synaptic plasticity, the long-term depression (LTD) elicited by activation of type-I metabotropic glutamate receptors (mGluR-LTD). mGluR-LTD was associated with calpain-1 activation following T-type calcium channel opening, and resulted in the truncation of a regulatory subunit of PP2A, B56α...
February 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28202809/mammal-body-size-evolution-in-north-america-and-europe-over-20-myr-similar-trends-generated-by-different-processes
#16
Shan Huang, Jussi T Eronen, Christine M Janis, Juha J Saarinen, Daniele Silvestro, Susanne A Fritz
Because body size interacts with many fundamental biological properties of a species, body size evolution can be an essential component of the generation and maintenance of biodiversity. Here we investigate how body size evolution can be linked to the clade-specific diversification dynamics in different geographical regions. We analyse an extensive body size dataset of Neogene large herbivores (covering approx. 50% of the 970 species in the orders Artiodactyla and Perissodactyla) in Europe and North America in a Bayesian framework...
February 22, 2017: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/28202592/extinction-pathways-and-outbreak-vulnerability-in-a-stochastic-ebola-model
#17
Garrett T Nieddu, Lora Billings, James H Kaufman, Eric Forgoston, Simone Bianco
A zoonotic disease is a disease that can be passed from animals to humans. Zoonotic viruses may adapt to a human host eventually becoming endemic in humans, but before doing so punctuated outbreaks of the zoonotic virus may be observed. The Ebola virus disease (EVD) is an example of such a disease. The animal population in which the disease agent is able to reproduce in sufficient number to be able to transmit to a susceptible human host is called a reservoir. There is little work devoted to understanding stochastic population dynamics in the presence of a reservoir, specifically the phenomena of disease extinction and reintroduction...
February 2017: Journal of the Royal Society, Interface
https://www.readbyqxmd.com/read/28202591/non-classical-phase-diagram-for-virus-bacterial-coevolution-mediated-by-clustered-regularly-interspaced-short-palindromic-repeats
#18
Pu Han, Michael W Deem
CRISPR is a newly discovered prokaryotic immune system. Bacteria and archaea with this system incorporate genetic material from invading viruses into their genomes, providing protection against future infection by similar viruses. The condition for coexistence of prokaryots and viruses is an interesting problem in evolutionary biology. In this work, we show an intriguing phase diagram of the virus extinction probability, which is more complex than that of the classical predator-prey model. As the CRISPR incorporates genetic material, viruses are under pressure to evolve to escape recognition by CRISPR...
February 2017: Journal of the Royal Society, Interface
https://www.readbyqxmd.com/read/28199203/neurogenetics-of-acute-and-chronic-opiate-opioid-abstinence-treating-symptoms-and-the-cause
#19
Kenneth Blum, Mark S Gold, William Jacobs, William Vaughn McCall, Marcelo Febo, David Baron, Kristina Dushaj, Zsolt Demetrovics, Rajendra D Badgaiyan
This review begins with a comprehensive history of opioid dependence and treatment in the United States. The focus is an evidence-based treatment model for opioid/opiate dependent individuals. The role of reward genetic polymorphisms and the epigenetic modifications that lead to vulnerability to use and misuse of opiates/opioid to treat pain are reviewed. The neurochemical mechanisms of acute opiate withdrawal and opiate/opioid reward mechanisms are explored with a goal of identifying specific treatment targets...
March 1, 2017: Frontiers in Bioscience (Landmark Edition)
https://www.readbyqxmd.com/read/28198872/high-extinction-ratio-integrated-photonic-filters-for-silicon-quantum-photonics
#20
Mateusz Piekarek, Damien Bonneau, Shigehito Miki, Taro Yamashita, Mikio Fujiwara, Masahide Sasaki, Hirotaka Terai, Michael G Tanner, Chandra M Natarajan, Robert H Hadfield, Jeremy L O'Brien, Mark G Thompson
We present the generation of quantum-correlated photon pairs and subsequent pump rejection across two silicon-on-insulator photonic integrated circuits. Incoherently cascaded lattice filters are used to provide over 100 dB pass-band to stop-band contrast with no additional external filtering. Photon pairs generated in a microring resonator are successfully separated from the input pump, confirmed by temporal correlations measurements.
February 15, 2017: Optics Letters
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