458 research outputs found

    Interspecific killing among mammalian carnivores

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    Interspecific killing among mammalian carnivores is common in nature and accounts for up to 68% of known mortalities in some species. Interactions may be symmetrical (both species kill each other) or asymmetrical (one species kills the other), and in some interactions adults of one species kill young but not adults of the other. There is a positive significant relationship between the body masses of solitary killer species and body masses of their victim species, and grouping species kill larger victims than solitary species. Interactions and consumption of the victim appear more common when food is scarce or disputed. In response to killers, victim species may alter their use of space, activity patterns, and form groups. Consequences of interspecific killing include population reduction or even extinction, and reduction and enhancement of prey popu- lations, and may therefore have important implications for conser- vation and management of carnivores and their preyPeer reviewe

    Floristic Composition Of A Neotropical Inselberg From EspĂ­rito Santo State, Brazil: An Important Area For Conservation

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    Our study on granitic and gneissic rock outcrops on Pedra dos PontÔes in Espírito Santo state contributes to the knowledge of the vascular flora of inselbergs in southeastern Brazil. We registered 211 species distributed among 51 families and 130 genera. Orchidaceae, Bromeliaceae and Polypodiaceae were the most representative families. Concerning vegetative habit, herbs were predominant and about the preference for substrates, holorupicolous species and epiphytes were most speciose. The richest rocky habitat type was woody thicket, with 122 exclusive species. In total, 27 of the species registered in our study are cited on official lists of endangered plant species from Espírito Santo state and Brazil. In addition, two new records of angiosperms for Espírito Santo flora and two new species were recorded for the area. Our data demonstrates the importance of the area for conservation of unique biodiversity that serves as a sanctuary for a rich rupicolous flora composed of endemic and endangered species, some of which are new to science. © 2017 Check List and Authors.13

    Enhanced electrocatalytic activity of Au@Cu core@shell nanoparticles towards CO2 reduction

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    The development of technologies for the recycling of carbon dioxide into carbon-containing fuels is one of the major challenges in sustainable energy research. Two of the main current limitations are the poor efficiency and fast deactivation of catalysts. Core–shell nanoparticles are promising candidates for enhancing challenging reactions. In this work, Au@Cu core–shell nanoparticles with well-defined surface structures were synthesized and evaluated as catalysts for the electrochemical reduction of carbon dioxide in neutral medium. The activation potential, the product distribution and the long term durability of this catalyst were assessed by electrochemical methods, on-line electrochemical mass spectrometry (OLEMS) and on-line high performance liquid chromatography. Our results show that the catalytic activity and the selectivity can be tweaked as a function of the thickness of Cu shells. We have observed that the Au cubic nanoparticles with 7–8 layers of copper present higher selectivity towards the formation of hydrogen and ethylene; on the other hand, we observed that Au cubic nanoparticles with more than 14 layers of Cu are more selective towards the formation of hydrogen and methane. A trend in the formation of the gaseous products can be also drawn. The H2 and CH4 formation increases with the number of Cu layers, while the formation of ethylene decreases. Formic acid was the only liquid species detected during CO2 reduction. Similar to the gaseous species, the formation of formic acid is strongly dependent on the number of Cu layers on the core@shell nanoparticles. The Au cubic nanoparticles with 7–8 layers of Cu showed the largest conversion of CO2 to formic acid at potentials higher than 0.8 V vs. RHE. The observed trends in reactivity and selectivity are linked to the catalyst composition, surface structure and strain/electronic effects

    Characterisation of biological growth curves of different varieties of an endangered native hen breed kept under free range conditions

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    The aim of this study is to model the growth samples of four varieties (White, Black, Partridge, Franciscan) of Spanish Utrerana hen breed, which is endangered, by using Brody, Von Bertalanffy, Verhulst, Logistic and Gompertz models. For this purpose, a total of 16,235 weight data observations from 2004 animals reared in free range system were collected. Logistic was the best suited model for predicting the biological growth curve of White variety in both sexes, while Von Bertalanffy was the best fitting model for the rest of individuals of the breed, based on the 5 goodness-of-fit and flexibility criteria: Pseudo-R2 , mean squared error, Akaike information criterion, Bayesian information criterion and the biological coherence of the estimated parameters. Black variety was the heaviest, with values of 2605.96 and 2032.61 g (for males and females, respectively) for a parameter, while White variety presented the lowest maturity weight (a Π2442.99 and 1874.24 g, for males and females, respectively). Conclusively, this growth characterisation is essential for the conservation of the Utrerana hen, to search for new market niches and a greater profitability to this differentiated product.info:eu-repo/semantics/publishedVersio

    Effect of the Interfacial Water Structure on the Hydrogen Evolution Reaction on Pt(111) Modified with Different Nickel Hydroxide Coverages in Alkaline Media

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    The hydrogen evolution reaction (HER) constitutes one of the most important reactions in electrochemistry because of the value of hydrogen as a vector for energy storage and transport. Therefore, understanding the mechanism of this reaction in relation to its pH dependence is of crucial importance. While the HER on Pt(111) works efficiently in acid media, in alkaline media, the reaction is impeded and considerably larger applied overpotentials are necessary. The presence of Ni(OH)2 adsorbed on Pt(111) has been demonstrated to highly improve the rate of hydrogen evolution, decreasing the overpotential of this reaction in comparison to acid media. The way low coverages of Ni(OH)2 on the Pt surface improve HER is still under discussion. In this work, we have prepared different Ni(OH)2 coverages on Pt(111) to check how Ni(OH)2 deposited on Pt(111) influences the HER rate. To this end, the Ni(OH)2–Pt(111)|0.1 M NaOH interface was characterized with cyclic voltammetry, CO displacement technique, and Fourier transform infrared-reflection absorption spectroscopy. On the basis of the proposal made by Ledezma-Yanez et al. [Nature Energy 2017, 2, 17031] to explain the HER in alkaline media, we also studied the effect of the different Ni(OH)2 coverages on the electric field using the laser-induced temperature jump technique. This technique revealed that introduction of nickel adlayers on the surface decreases the ordering of the water network at the interphase, a fact that has relevant implications for the HER mechanism.The authors thankfully acknowledge financial support from the MICINN (Spain) through project CTQ2016-76221-P. P. Sebastian acknowledges to MECD the award of a FPU grant. F.J.S. acknowledges to Ministerio de Economia, Industria y Competitividad (PEJ-2014-A-57942/PEJ-2014-P-00295)

    Robust skill of decadal climate predictions

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    There is a growing need for skilful predictions of climate up to a decade ahead. Decadal climate predictions show high skill for surface temperature, but confidence in forecasts of precipitation and atmospheric circulation is much lower. Recent advances in seasonal and annual prediction show that the signal-to-noise ratio can be too small in climate models, requiring a very large ensemble to extract the predictable signal. Here, we reassess decadal prediction skill using a much larger ensemble than previously available, and reveal significant skill for precipitation over land and atmospheric circulation, in addition to surface temperature. We further propose a more powerful approach than used previously to evaluate the benefit of initialisation with observations, improving our understanding of the sources of skill. Our results show that decadal climate is more predictable than previously thought and will aid society to prepare for, and adapt to, ongoing climate variability and change.D.M.S., A.A.S., N.J.D., L.H. and R.E. were supported by the Met Office Hadley Centre Climate Programme funded by BEIS and Defra and by the European Commission Horizon 2020 EUCP project (GA 776613). L.P.C. was supported by the Spanish MINECO HIATUS (CGL2015-70353-R) project. F.J.D.R. was supported by the H2020 EUCP (GA 776613) and the Spanish MINECO CLINSA (CGL2017-85791-R) projects. W.A. M. and H.P. were supported by the German Ministry of Education and Research (BMBF) under the project MiKlip (grant 01LP1519A). The NCAR contribution was supported by the US National Oceanic and Atmospheric Administration (NOAA) Climate Program Office under Climate Variability and Predictability Program Grant NA13OAR4310138 and by the US National Science Foundation (NSF) Collaborative Research EaSM2 Grant OCE-1243015. The NCAR contribution is also based upon work supported by NCAR, which is a major facility sponsored by the US NSF under Cooperative Agreement No. 1852977. The Community Earth System Model Decadal Prediction Large Ensemble (CESM-DPLE) was generated using computational resources provided by the US National Energy Research Scientific Computing Center, which is supported by the Office of Science of the US Department of Energy under Contract DE-AC02-05CH11231, as well as by an Accelerated Scientific Discovery grant for Cheyenne (https://doi.org/10.5065/D6RX99HX) that was awarded by NCAR’s Computational and Information System Laboratory.Peer ReviewedPostprint (published version

    Measurement of the Bs0→J/ψKS0B_s^0\to J/\psi K_S^0 branching fraction

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    The Bs0→J/ψKS0B_s^0\to J/\psi K_S^0 branching fraction is measured in a data sample corresponding to 0.41fb−1fb^{-1} of integrated luminosity collected with the LHCb detector at the LHC. This channel is sensitive to the penguin contributions affecting the sin2ÎČ\beta measurement from B0→J/ψKS0B^0\to J/\psi K_S^0 The time-integrated branching fraction is measured to be BF(Bs0→J/ψKS0)=(1.83±0.28)×10−5BF(B_s^0\to J/\psi K_S^0)=(1.83\pm0.28)\times10^{-5}. This is the most precise measurement to date

    Model-independent search for CP violation in D0→K−K+π−π+ and D0→π−π+π+π− decays

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    A search for CP violation in the phase-space structures of D0 and View the MathML source decays to the final states K−K+π−π+ and π−π+π+π− is presented. The search is carried out with a data set corresponding to an integrated luminosity of 1.0 fb−1 collected in 2011 by the LHCb experiment in pp collisions at a centre-of-mass energy of 7 TeV. For the K−K+π−π+ final state, the four-body phase space is divided into 32 bins, each bin with approximately 1800 decays. The p-value under the hypothesis of no CP violation is 9.1%, and in no bin is a CP asymmetry greater than 6.5% observed. The phase space of the π−π+π+π− final state is partitioned into 128 bins, each bin with approximately 2500 decays. The p-value under the hypothesis of no CP violation is 41%, and in no bin is a CP asymmetry greater than 5.5% observed. All results are consistent with the hypothesis of no CP violation at the current sensitivity

    Measurement of the CP-violating phase \phi s in Bs->J/\psi\pi+\pi- decays

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    Measurement of the mixing-induced CP-violating phase phi_s in Bs decays is of prime importance in probing new physics. Here 7421 +/- 105 signal events from the dominantly CP-odd final state J/\psi pi+ pi- are selected in 1/fb of pp collision data collected at sqrt{s} = 7 TeV with the LHCb detector. A time-dependent fit to the data yields a value of phi_s=-0.019^{+0.173+0.004}_{-0.174-0.003} rad, consistent with the Standard Model expectation. No evidence of direct CP violation is found.Comment: 15 pages, 10 figures; minor revisions on May 23, 201

    Search for the lepton-flavor-violating decays Bs0→e±Ό∓ and B0→e±Ό∓

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    A search for the lepton-flavor-violating decays Bs0→e±Ό∓ and B0→e±Ό∓ is performed with a data sample, corresponding to an integrated luminosity of 1.0  fb-1 of pp collisions at √s=7  TeV, collected by the LHCb experiment. The observed number of Bs0→e±Ό∓ and B0→e±Ό∓ candidates is consistent with background expectations. Upper limits on the branching fractions of both decays are determined to be B(Bs0→e±Ό∓)101  TeV/c2 and MLQ(B0→e±Ό∓)>126  TeV/c2 at 95% C.L., and are a factor of 2 higher than the previous bounds
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