2,962 research outputs found

    Beyond Shooting Snaildarters in Porkbarrels: Endangered Species and Land Use in America

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    This article examines endangered species law as it may affect land use in the United States. The first section describes the legal and biological contexts into which the ESA intruded. Section II outlines the protective mechanisms established by the 1973 version of the Act and their reception by the courts. The third section discusses the corrective amendments to the Act enacted in 1978. The final section applies the law as it has developed and as it is likely to evolve to a series of more or less hypothetical land use conflicts, forecasting multiplication of the disputes between endangered species and human desires

    12.グルタミン酸ナトリウムはglucagon like peptide-1の食後早期の分泌を促進し, 食後血糖の上昇を抑制する

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    The purpose of this study was to compare the growth and nutritional status of infants fed different diets, some of whom received a low-fat formula. Beginning at four to six months of age, 101 infants were fed whole cow\u27s milk, one of two low-fat follow-up formulas, or a standard infant formula until 12 months of age. Weight, recumbent length, and head circumference were measured at one-month intervals. Analyses of status (values at an age) for all examinations showed no significant differences among the feeding groups in status for weight or recumbent length, but there were significant differences in head circumference for boys and for girls after adjustments for the initial values. Head circumferences were smaller in those fed whole cow\u27s milk and relatively large in those fed follow-up formula, but these differences were small and not of clinical significance. Comparisons with national reference data showed growth in weight, recumbent length, and head circumference was normal regardless of feeding group. These results indicate that, during the second half year of infancy, the use of lower fat concentrations in the follow-up formulas did not retard growth in weight, recumbent length, or head circumference

    The gravitational-wave background null hypothesis: Characterizing noise in millisecond pulsar arrival times with the Parkes Pulsar Timing Array

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    The noise in millisecond pulsar (MSP) timing data can include contributions from observing instruments, the interstellar medium, the solar wind, solar system ephemeris errors, and the pulsars themselves. The noise environment must be accurately characterized in order to form the null hypothesis from which signal models can be compared, including the signature induced by nanohertz-frequency gravitational waves (GWs). Here we describe the noise models developed for each of the MSPs in the Parkes Pulsar Timing Array (PPTA) third data release, which have been used as the basis of a search for the isotropic stochastic GW background. We model pulsar spin noise, dispersion measure variations, scattering variations, events in the pulsar magnetospheres, solar wind variability, and instrumental effects. We also search for new timing model parameters and detected Shapiro delays in PSR~J0614-3329 and PSR~J1902-5105. The noise and timing models are validated by testing the normalized and whitened timing residuals for Gaussianity and residual correlations with time. We demonstrate that the choice of noise models significantly affects the inferred properties of a common-spectrum process. Using our detailed models, the recovered common-spectrum noise in the PPTA is consistent with a power law with a spectral index of γ=13/3\gamma=13/3, the value predicted for a stochastic GW background from a population of supermassive black hole binaries driven solely by GW emission.Comment: 18 pages, 10 figures. Accepted for publication in ApJ

    Search for an isotropic gravitational-wave background with the Parkes Pulsar Timing Array

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    Pulsar timing arrays aim to detect nanohertz-frequency gravitational waves (GWs). A background of GWs modulates pulsar arrival times and manifests as a stochastic process, common to all pulsars, with a signature spatial correlation. Here we describe a search for an isotropic stochastic gravitational-wave background (GWB) using observations of 30 millisecond pulsars from the third data release of the Parkes Pulsar Timing Array (PPTA), which spans 18 years. Using current Bayesian inference techniques we recover and characterize a common-spectrum noise process. Represented as a strain spectrum hc=A(f/1yr1)αh_c = A(f/1 {\rm yr}^{-1})^{\alpha}, we measure A=3.10.9+1.3×1015A=3.1^{+1.3}_{-0.9} \times 10^{-15} and α=0.45±0.20\alpha=-0.45 \pm 0.20 respectively (median and 68% credible interval). For a spectral index of α=2/3\alpha=-2/3, corresponding to an isotropic background of GWs radiated by inspiraling supermassive black hole binaries, we recover an amplitude of A=2.040.22+0.25×1015A=2.04^{+0.25}_{-0.22} \times 10^{-15}. However, we demonstrate that the apparent signal strength is time-dependent, as the first half of our data set can be used to place an upper limit on AA that is in tension with the inferred common-spectrum amplitude using the complete data set. We search for spatial correlations in the observations by hierarchically analyzing individual pulsar pairs, which also allows for significance validation through randomizing pulsar positions on the sky. For a process with α=2/3\alpha=-2/3, we measure spatial correlations consistent with a GWB, with an estimated false-alarm probability of p0.02p \lesssim 0.02 (approx. 2σ2\sigma). The long timing baselines of the PPTA and the access to southern pulsars will continue to play an important role in the International Pulsar Timing Array.Comment: 19 pages, 10 figures, Accepted for publication in ApJ

    Towards an integrative understanding of soil biodiversity

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    Soil is one of the most biodiverse terrestrial habitats. Yet, we lack an integrative conceptual framework for understanding the patterns and mechanisms driving soil biodiversity. One of the underlying reasons for our poor understanding of soil biodiversity patterns relates to whether key biodiversity theories (historically developed for aboveground and aquatic organisms) are applicable to patterns of soil biodiversity. Here, we present a systematic literature review to investigate whether and how key biodiversity theories (species-energy relationship, theory of island biogeography, metacommunity theory, niche theory and neutral theory) can explain observed patterns of soil biodiversity. We then discuss two spatial compartments nested within soil at which biodiversity theories can be applied to acknowledge the scale-dependent nature of soil biodiversity.Peer reviewe

    The Astropy Problem

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    The Astropy Project (http://astropy.org) is, in its own words, "a community effort to develop a single core package for Astronomy in Python and foster interoperability between Python astronomy packages." For five years this project has been managed, written, and operated as a grassroots, self-organized, almost entirely volunteer effort while the software is used by the majority of the astronomical community. Despite this, the project has always been and remains to this day effectively unfunded. Further, contributors receive little or no formal recognition for creating and supporting what is now critical software. This paper explores the problem in detail, outlines possible solutions to correct this, and presents a few suggestions on how to address the sustainability of general purpose astronomical software

    Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

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    This paper presents measurements of the W+μ+νW^+ \rightarrow \mu^+\nu and WμνW^- \rightarrow \mu^-\nu cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13

    Search for squarks and gluinos in events with isolated leptons, jets and missing transverse momentum at s√=8 TeV with the ATLAS detector

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    The results of a search for supersymmetry in final states containing at least one isolated lepton (electron or muon), jets and large missing transverse momentum with the ATLAS detector at the Large Hadron Collider are reported. The search is based on proton-proton collision data at a centre-of-mass energy s√=8 TeV collected in 2012, corresponding to an integrated luminosity of 20 fb−1. No significant excess above the Standard Model expectation is observed. Limits are set on supersymmetric particle masses for various supersymmetric models. Depending on the model, the search excludes gluino masses up to 1.32 TeV and squark masses up to 840 GeV. Limits are also set on the parameters of a minimal universal extra dimension model, excluding a compactification radius of 1/R c = 950 GeV for a cut-off scale times radius (ΛR c) of approximately 30
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