keyword
MENU ▼
Read by QxMD icon Read
search

Extinction

keyword
https://www.readbyqxmd.com/read/28433817/climate-change-risks-extinction-debt-and-conservation-implications-for-a-threatened-freshwater-fish-carmine-shiner-notropis-percobromus
#1
Shubha N Pandit, Bryan M Maitland, Laxmi K Pandit, Mark S Poesch, Eva C Enders
Climate change is affecting many freshwater species, particularly fishes. Predictions of future climate change suggest large and deleterious effects on species with narrow dispersal abilities due to limited hydrological connectivity. In turn, this creates the potential for population isolation in thermally unsuitable habitats, leading to physiological stress, species declines or possible extirpation. The current extent of many freshwater fish species' spatio-temporal distribution patterns and their sensitivity to thermal impacts from climate change - critical information for conservation planning - are often unknown...
April 20, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28433588/how-environmental-noise-can-contract-and-destroy-a-persistence-zone-in-population-models-with-allee-effect
#2
Irina Bashkirtseva, Lev Ryashko
A problem of the analysis of the noise-induced extinction in population models with Allee effect is considered. To clarify mechanisms of the extinction, we suggest a new technique combining an analysis of the geometry of attractors and their stochastic sensitivity. For the conceptual one-dimensional discrete Ricker-type model, on the base of the bifurcation analysis, deterministic persistence zones are constructed in the space of initial states and biological parameters. It is shown that the random environmental noise can contract, and even destroy these persistence zones...
April 19, 2017: Theoretical Population Biology
https://www.readbyqxmd.com/read/28432634/new-chromophore-systems-from-coumarin-oxazol-5-one-combination
#3
Derya Topkaya, Serap Alp
Coumarin-oxazol-5-one (COX), 3a-d, were synthesized with 7-methoxy-2-oxo-2H-chromene-4-carbaldehyde and benzoylglycine derivatives. The characterizations of the COX derivatives by (1)H NMR, FT-IR and elemental analysis were achieved. To obtain the photophysical data of the synthesized COX derivatives were used spectrophotometric and spectrofluorimetric methods. Evaluation of the absorption and emission properties of the structures was carried out in six different solvents. Maximum absorption and emission wavelengths (λ; nm), molar extinction coefficients (ε; cm(-1) M(-1)), Stoke's shifts (ΔλST; nm) and quantum yields (ϕF), of the COX derivatives were declared...
April 22, 2017: Journal of Fluorescence
https://www.readbyqxmd.com/read/28432484/complete-mitochondrial-genome-sequences-of-korean-native-horse-from-jeju-island-uncovering-the-spatio-temporal-dynamics
#4
Sook Hee Yoon, Jaemin Kim, Donghyun Shin, Seoae Cho, Woori Kwak, Hak-Kyo Lee, Kyoung-Do Park, Heebal Kim
The Korean native horse (Jeju horse) is one of the most important animals in Korean historical, cultural, and economical viewpoints. In the early 1980s, the Jeju horse was close to extinction. The aim of this study is to explore the phylogenomics of Korean native horse focusing on spatio-temporal dynamics. We determined complete mitochondrial genome sequences for the first Korean native (n = 6) and additional Mongolian (n = 2) horses. Those sequences were analyzed together with 143 published ones using Bayesian coalescent approach as well as three different phylogenetic analysis methods, Bayesian inference, maximum likelihood, and neighbor-joining methods...
April 21, 2017: Molecular Biology Reports
https://www.readbyqxmd.com/read/28432393/more-functions-of-torpor-and-their-roles-in-a-changing-world
#5
Julia Nowack, Clare Stawski, Fritz Geiser
Increased winter survival by reducing energy expenditure in adult animals is often viewed as the primary function of torpor. However, torpor has many other functions that ultimately increase the survival of heterothermic mammals and birds. In this review, we summarize new findings revealing that animals use torpor to cope with the conditions during and after natural disasters, including fires, storms, and heat waves. Furthermore, we suggest that torpor, which also prolongs longevity and was likely crucial for survival of mammals during the time of the dinosaur extinctions, will be advantageous in a changing world...
April 21, 2017: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://www.readbyqxmd.com/read/28432257/excess-diffuse-light-absorption-in-upper-mesophyll-limits-co2-drawdown-and-depresses-photosynthesis
#6
Jeffrey Mason Earles, Guillaume Théroux-Rancourt, Matthew E Gilbert, Andrew J McElrone, Craig Brodersen
In agricultural and natural systems, diffuse light can enhance plant primary productivity due to deeper penetration into and greater illumination of the entire canopy. However, for individual sun-grown leaves from three species, photosynthesis is actually less efficient under diffuse compared to direct light. Despite its potential impact on canopy-level productivity, the mechanism for this leaf-level 'diffuse light photosynthetic depression' effect is unknown. Here we investigate if the spatial distribution of light absorption relative to electron transport capacity in sun- and shade-grown H...
April 21, 2017: Plant Physiology
https://www.readbyqxmd.com/read/28431947/a-bout-analysis-of-operant-response-disruption
#7
REVIEW
Ryan J Brackney, Timothy H Cheung, Federico Sanabria
Operant behavior appears to be organized in bouts of responses, whose parameters are differentially sensitive to various manipulations. This study investigated potential differential effects of three forms of operant response disruption-extinction (EXT), non-contingent reinforcement (NCR), and prefeeding (PRE)-on response bouts. In Experiment 1, Wistar Kyoto rats (WKY) were trained on a tandem variable-time (VT) 120s fixed-ratio (FR) 5 schedule of reinforcement; after stability was established, their responding was disrupted for three sessions with one of the three disrupters (EXT, NCR, or PRE)...
April 18, 2017: Behavioural Processes
https://www.readbyqxmd.com/read/28431159/likelihood-of-tree-topologies-with-fossils-and-diversification-rate-estimation
#8
Gilles Didier, Marine Fau, Michel Laurin
Since the diversification process cannot be directly observed at the human scale, it has to be studied from the information available, namely the extant taxa and the fossil record. In this sense, phylogenetic trees including both extant taxa and fossils are the most complete representations of the diversification process that one can get. Such phylogenetic trees can be reconstructed from molecular and morphological data, to some extent. Among the temporal information of such phylogenetic trees, fossil ages are by far the most precisely known (divergence times are inferences calibrated mostly with fossils)...
April 18, 2017: Systematic Biology
https://www.readbyqxmd.com/read/28431105/extinction-vs-rapid-radiation-the-juxtaposed-evolutionary-histories-of-coelotine-spiders-support-the-eocene-oligocene-orogenesis-of-the-tibetan-plateau
#9
Zhe Zhao, Shuqiang Li
Evolutionary biology has long been concerned with how changing environments affect and drive the spatiotemporal development of organisms. Coelotine spiders (Agelenidae: Coelotinae) are common species in the temperate and subtropical areas of the Northern Hemisphere. Their long evolutionary history and the extremely imbalanced distribution of species richness suggest that Eurasian environments, especially since the Cenozoic, are the drivers of their diversification. We use phylogenetics, molecular dating, ancestral area reconstructions, diversity, and ecological niche analyses to investigate the spatiotemporal evolution of 286 coelotine species from throughout the region...
April 20, 2017: Systematic Biology
https://www.readbyqxmd.com/read/28430233/sensitivity-tests-on-the-convergence-tendency-of-the-scattering-order-formulation-of-the-discrete-dipole-approximation
#10
Carynelisa Haspel, Masada Tzabari
In this study, we performed a series of sensitivity tests in order to elucidate the convergence tendency of the scattering order formulation (SOF) of the discrete dipole approximation (DDA). Using both the original formulation of the SOF and a new marching SOF, the progression of orders of scattering marches, along with the propagation of the incident plane wave through the scatterer, allow dipoles that come into steady-state oscillation with the incident wave earlier to more quickly advance to the next order of scattering that is local to them...
April 20, 2017: Applied Optics
https://www.readbyqxmd.com/read/28429682/refractive-index-and-extinction-coefficient-of-nh2ch-nh2pbi3-perovskite-photovoltaic-material
#11
Ziang Xie, Shuren Sun, Yu Yan, Lili Zhang, Ruixiang Hou, Fuyang Tian, Guogang Qin
Very recently, the NH2CH=NH2PbI3 (FAPbI3) perovskite material has attracted much attention in fabricating solar cells (SCs). For a photovoltaic material, its refractive index and extinction coefficient, n(λ) and k(λ), as functions of λ, are important to study its optical properties and to estimate the power conversion efficiency potential for the SCs made of it. As far as we know, so far there is no reporting of n(λ) and k(λ) for the FAPbI3 material. In this article, with spectroscopic ellipsometry (SE) measurements, the n(λ) and k(λ), as well as Eg = 1...
April 21, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28428872/are-whooping-cranes-destined-for-extinction-climate-change-imperils-recruitment-and-population-growth
#12
Matthew J Butler, Kristine L Metzger, Grant M Harris
Identifying climatic drivers of an animal population's vital rates and locating where they operate steers conservation efforts to optimize species recovery. The population growth of endangered whooping cranes (Grus americana) hinges on juvenile recruitment. Therefore, we identify climatic drivers (solar activity [sunspots] and weather) of whooping crane recruitment throughout the species' life cycle (breeding, migration, wintering). Our method uses a repeated cross-validated absolute shrinkage and selection operator approach to identify drivers of recruitment...
April 2017: Ecology and Evolution
https://www.readbyqxmd.com/read/28428864/integrating-biogeography-threat-and-evolutionary-data-to-explore-extinction-crisis-in-the-taxonomic-group-of-cycads
#13
Kowiyou Yessoufou, Barnabas H Daru, Respinah Tafirei, Hosam O Elansary, Isaac Rampedi
Will the ongoing extinction crisis cause a severe loss of evolutionary information accumulated over millions of years on the tree of life? This question has been largely explored, particularly for vertebrates and angiosperms. However, no equivalent effort has been devoted to gymnosperms. Here, we address this question focusing on cycads, the gymnosperm group exhibiting the highest proportion of threatened species in the plant kingdom. We assembled the first complete phylogeny of cycads and assessed how species loss under three scenarios would impact the cycad tree of life...
April 2017: Ecology and Evolution
https://www.readbyqxmd.com/read/28428561/a-general-framework-for-predicting-delayed-responses-of-ecological-communities-to-habitat-loss
#14
Youhua Chen, Tsung-Jen Shen
Although biodiversity crisis at different spatial scales has been well recognised, the phenomena of extinction debt and immigration credit at a crossing-scale context are, at best, unclear. Based on two community patterns, regional species abundance distribution (SAD) and spatial abundance distribution (SAAD), Kitzes and Harte (2015) presented a macroecological framework for predicting post-disturbance delayed extinction patterns in the entire ecological community. In this study, we further expand this basic framework to predict diverse time-lagged effects of habitat destruction on local communities...
April 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28426077/robust-raspberry-like-metallo-dielectric-nanoclusters-of-critical-sizes-as-sers-substrates
#15
A Le Beulze, S Gomez-Graña, H Gehan, S Mornet, S Ravaine, M Correa-Duarte, L Guerrini, R A Alvarez-Puebla, E Duguet, E Pertreux, A Crut, P Maioli, F Vallée, N Del Fatti, O Ersen, M Treguer-Delapierre
Raspberry-like nano-objects made of large plasmonic satellites (>10 nm) covering a central dielectric particle have many potential applications as photonic materials, superlenses and (bio-) sensors, but their synthesis remains challenging. Herein, we show how to build stable and robust raspberry-like nano-systems with close-packed satellites, by combining monodisperse silica particles (80 or 100 nm diameter) and oppositely charged noble metal nanoparticles (Au or Ag) with well-defined sizes (10-50 nm). The spectral characteristics of their associated plasmonic resonances (wavelength, linewidth, extinction cross-section) and the electromagnetic coupling between satellites were observed using the spatial modulation spectroscopy technique and interpreted through a numerical model...
April 20, 2017: Nanoscale
https://www.readbyqxmd.com/read/28425998/drivers-of-salamander-extirpation-mediated-by-batrachochytrium-salamandrivorans
#16
Gwij Stegen, Frank Pasmans, Benedikt R Schmidt, Lieze O Rouffaer, Sarah Van Praet, Michael Schaub, Stefano Canessa, Arnaud Laudelout, Thierry Kinet, Connie Adriaensen, Freddy Haesebrouck, Wim Bert, Franky Bossuyt, An Martel
The recent arrival of Batrachochytrium salamandrivorans in Europe was followed by rapid expansion of its geographical distribution and host range, confirming the unprecedented threat that this chytrid fungus poses to western Palaearctic amphibians. Mitigating this hazard requires a thorough understanding of the pathogen's disease ecology that is driving the extinction process. Here, we monitored infection, disease and host population dynamics in a Belgian fire salamander (Salamandra salamandra) population for two years immediately after the first signs of infection...
April 19, 2017: Nature
https://www.readbyqxmd.com/read/28424345/floaters-may-buffer-the-extinction-risk-of-small-populations-an-empirical-assessment
#17
Hugo Robles, Carlos Ciudad
The high extinction risk of small populations is commonly explained by reductions in fecundity and breeder survival associated with demographic and environmental stochasticity. However, ecological theory suggests that population extinctions may also arise from reductions in the number of floaters able to replace the lost breeders. This can be particularly plausible under harsh fragmentation scenarios, where species must survive as small populations subjected to severe effects of stochasticity. Using a woodpecker study in fragmented habitats (2004-2016), we provide here empirical support for the largely neglected hypothesis that floaters buffer population extirpation risks...
April 26, 2017: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/28423030/molecular-characterization-of-cryptosporidium-and-giardia-from-the-tasmanian-devil-sarcophilus-harrisii
#18
Liana F Wait, Samantha Fox, Sarah Peck, Michelle L Power
The Tasmanian devil (Sarcophilus harrisii) is a carnivorous marsupial found only in the wild in Tasmania, Australia. Tasmanian devils are classified as endangered and are currently threatened by devil facial tumour disease, a lethal transmissible cancer that has decimated the wild population in Tasmania. To prevent extinction of Tasmanian devils, conservation management was implemented in 2003 under the Save the Tasmanian Devil Program. This study aimed to assess if conservation management was altering the interactions between Tasmanian devils and their parasites...
2017: PloS One
https://www.readbyqxmd.com/read/28423005/an-archosauromorph-dominated-ichnoassemblage-in-fluvial-settings-from-the-late-early-triassic-of-the-catalan-pyrenees-ne-iberian-peninsula
#19
Eudald Mujal, Josep Fortuny, Arnau Bolet, Oriol Oms, José Ángel López
The vertebrate recovery after the end-Permian mass extinction can be approached through the ichnological record, which is much more abundant than body fossils. The late Olenekian (Early Triassic) tetrapod ichnoassemblage of the Catalan Pyrenean Basin is the most complete and diverse of this age from Western Tethys. This extensional basin, composed of several depocenters, was formed in the latest phases of the Variscan orogeny (Pangea breakup) and was infilled by braided and meandering fluvial systems of the red-beds Buntsandstein facies...
2017: PloS One
https://www.readbyqxmd.com/read/28423000/inbreeding-and-selection-shape-genomic-diversity-in-captive-populations-implications-for-the-conservation-of-endangered-species
#20
Janna R Willoughby, Jamie A Ivy, Robert C Lacy, Jacqueline M Doyle, J Andrew DeWoody
Captive breeding programs are often initiated to prevent species extinction until reintroduction into the wild can occur. However, the evolution of captive populations via inbreeding, drift, and selection can impair fitness, compromising reintroduction programs. To better understand the evolutionary response of species bred in captivity, we used nearly 5500 single nucleotide polymorphisms (SNPs) in populations of white-footed mice (Peromyscus leucopus) to measure the impact of breeding regimes on genomic diversity...
2017: PloS One
keyword
keyword
18144
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"