21,257 research outputs found

    Critical Review of Richard Moran, The Exchange of Words

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    Moran's book is sure to be widely read. It does more to bring to light the moral psychology characteristic of tellings understood as assurances than any other work I know. His book raises challenges for other views, introduces interesting and evocative distinctions, and puts together in one place Moran's sustained reflections on the way we provide others a distinctive kind of reason for belief though normatively binding ourselves though the exchange of words. I agree that assurances and acceptances in Moran's sense play a part in a total understanding of the epistemology of testimony. But I do not agree they cover the whole terrain. There is much more to the metaphysics and epistemology of testimony still to explore

    Localizing Gravitational Wave Sources with Single-Baseline Atom Interferometers

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    Localizing sources on the sky is crucial for realizing the full potential of gravitational waves for astronomy, astrophysics, and cosmology. We show that the mid-frequency band, roughly 0.03 to 10 Hz, has significant potential for angular localization. The angular location is measured through the changing Doppler shift as the detector orbits the Sun. This band maximizes the effect since these are the highest frequencies in which sources live several months. Atom interferometer detectors can observe in the mid-frequency band, and even with just a single baseline can exploit this effect for sensitive angular localization. The single baseline orbits around the Earth and the Sun, causing it to reorient and change position significantly during the lifetime of the source, and making it similar to having multiple baselines/detectors. For example, atomic detectors could predict the location of upcoming black hole or neutron star merger events with sufficient accuracy to allow optical and other electromagnetic telescopes to observe these events simultaneously. Thus, mid-band atomic detectors are complementary to other gravitational wave detectors and will help complete the observation of a broad range of the gravitational spectrum.Comment: 16 pages, 3 figures, 2 table

    A Second Crystal Polymorph of Anilinium Picrate

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    The crystal structure of a second monoclinic polymorph of anilinium picrate shows a three-dimensional hydrogen-bonded polymer with strong primary interspecies interactions involving the proximal phenolate and adjacent nitro group O-atom acceptors and separate anilinium H-atom donors in two cyclic R (6) associations. Other nitro-O-anilinium-H hydrogen bonds together with heteromolecular interactions are also present

    Disentangling the effects of geographic and ecological isolation on genetic differentiation

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    Populations can be genetically isolated both by geographic distance and by differences in their ecology or environment that decrease the rate of successful migration. Empirical studies often seek to investigate the relationship between genetic differentiation and some ecological variable(s) while accounting for geographic distance, but common approaches to this problem (such as the partial Mantel test) have a number of drawbacks. In this article, we present a Bayesian method that enables users to quantify the relative contributions of geographic distance and ecological distance to genetic differentiation between sampled populations or individuals. We model the allele frequencies in a set of populations at a set of unlinked loci as spatially correlated Gaussian processes, in which the covariance structure is a decreasing function of both geographic and ecological distance. Parameters of the model are estimated using a Markov chain Monte Carlo algorithm. We call this method Bayesian Estimation of Differentiation in Alleles by Spatial Structure and Local Ecology (BEDASSLE), and have implemented it in a user-friendly format in the statistical platform R. We demonstrate its utility with a simulation study and empirical applications to human and teosinte datasets

    Guanidinium 2-Carboxy-6-Nitrobenzoate Monohydrate: A Two-Dimensional Hydrogen-Bonded Network Structure

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    In the structure of the title compound, CH6N3+ . C8H4NO6- . H2O, obtained from the reaction of guanidine carbonate with 3-nitrophthalic acid, the 2-carboxylic acid group is deprotonated and participates in an asymmetric cyclic R2/1(6) hydrogen-bonding associatiuon with the guanidine cation together with a bridging water molecule of solvation. A conjoint R2/1(7) facial association involving a nitro O-atom acceptor together with a further five guanidinium N-H...O hydrogen bonds, as well as a strong carboxyl-water interaction [2.528(3) Ang.], give a two-dimensiional network structure

    Luminous Dark Matter

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    We propose a dark matter model in which the signal in direct detection experiments arises from electromagnetic, not nuclear, energy deposition. This can provide a novel explanation for DAMA while avoiding many direct detection constraints. The dark matter state is taken nearly degenerate with another state. These states are naturally connected by a dipole moment operator, which can give both the dominant scattering and decay modes between the two states. The signal at DAMA then arises from dark matter scattering in the Earth into the excited state and decaying back to the ground state through emission of a single photon in the detector. This model has unique signatures in direct detection experiments. The density and chemical composition of the detector is irrelevant, only the total volume affects the event rate. In addition, the spectrum is a monoenergetic line, which can fit the DAMA signal well. This model is readily testable at experiments such as CDMS and XENON100 if they analyze their low-energy, electronic recoil events.Comment: 23 pages, 3 figures, journal version, added discussion of daily modulation, changed axes label of figure
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