3,183 research outputs found

    Bibliometrics : an overview

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    Research support is an expanding area of activity for libraries in the HE sector. At the University of Hull, the recent reorganisation of Library and Learning Innovation involved a redistribution of expertise to meet the changing needs of the University, its staff and students. As part of this, a new Research Services Team was created to meet the needs of the research community and so contribute to a key strategic aim of increasing the quantity and quality of research outputs

    Binary black hole merger: symmetry and the spin expansion

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    We regard binary black hole (BBH) merger as a map from a simple initial state (two Kerr black holes, with dimensionless spins {\bf a} and {\bf b}) to a simple final state (a Kerr black hole with mass m, dimensionless spin {\bf s}, and kick velocity {\bf k}). By expanding this map around {\bf a} = {\bf b} = 0 and applying symmetry constraints, we obtain a simple formalism that is remarkably successful at explaining existing BBH simulations. It also makes detailed predictions and suggests a more efficient way of mapping the parameter space of binary black hole merger. Since we rely on symmetry rather than dynamics, our expansion complements previous analytical techniques.Comment: 4 pages, 4 figures, matches Phys. Rev. Lett. versio

    Discovering Summon

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    Transits and Occultations of an Earth-Sized Planet in an 8.5-Hour Orbit

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    We report the discovery of an Earth-sized planet (1.16±0.19R1.16\pm 0.19 R_\oplus) in an 8.5-hour orbit around a late G-type star (KIC 8435766, Kepler-78). The object was identified in a search for short-period planets in the {\it Kepler} database and confirmed to be a transiting planet (as opposed to an eclipsing stellar system) through the absence of ellipsoidal light variations or substantial radial-velocity variations. The unusually short orbital period and the relative brightness of the host star (mKepm_{\rm Kep} = 11.5) enable robust detections of the changing illumination of the visible hemisphere of the planet, as well as the occultations of the planet by the star. We interpret these signals as representing a combination of reflected and reprocessed light, with the highest planet dayside temperature in the range of 2300 K to 3100 K. Follow-up spectroscopy combined with finer sampling photometric observations will further pin down the system parameters and may even yield the mass of the planet.Comment: Accepted for publication, ApJ, 10 pages and 6 figure

    Spin orbit alignment for KELT-7b and HAT-P-56b via Doppler tomography with TRES

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    We present Doppler tomographic analyses for the spectroscopic transits of KELT-7b and HAT-P-56b, two hot-Jupiters orbiting rapidly rotating F-dwarf host stars. These include analyses of archival TRES observations for KELT-7b, and a new TRES transit observation of HAT-P-56b. We report spin-orbit aligned geometries for KELT-7b (2.7 +/- 0.6 deg) and HAT-P-56b (8 +/- 2 deg). The host stars KELT-7 and HAT-P-56 are among some of the most rapidly rotating planet-hosting stars known. We examine the tidal re-alignment model for the evolution of the spin-orbit angle in the context of the spin rates of these stars. We find no evidence that the rotation rates of KELT-7 and HAT-P-56 have been modified by star-planet tidal interactions, suggesting that the spin-orbit angle of systems around these hot stars may represent their primordial configuration. In fact, KELT-7 and HAT-P-56 are two of three systems in super-synchronous, spin-orbit aligned states, where the rotation periods of the host stars are faster than the orbital periods of the planets.Comment: 9 pages, accepted for publication in MNRA

    Repositioning Information Science.

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    International audienceDuring the twentieth century there was a strong desire for information studies to become scientific, to move from librarianship, bibliography, and documentation to an information science. In 1968 the American Documentation Institute was renamed American Society for Information Science. By the twenty-first century, however, departments of (library and) information science had turned instead towards the social sciences, but have not been successful in providing a coherent explanation of the nature and scope of the field. The accepted view of Information Science as an emerging, scientific discipline closely tied with Information Technology and, mainly, textual data, will be challenged. Three brief presentations proposing different foundations and directions as a basis for a moderated discussion: There are other options: The development of Information Science in France has been radically different and has from the start been steeped in the humanities. The scope and focus should be broader to include, for example, the cognitive and aesthetic experiences of museum visitors? If Information Science is really concerned with influencing what people know, what kind of science can Information Science be

    The Transit Light Curve Project. VII. The Not-So-Bloated Exoplanet HAT-P-1b

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    We present photometry of the G0 star HAT-P-1 during six transits of its close-in giant planet, and we refine the estimates of the system parameters. Relative to Jupiter's properties, HAT-P-1b is 1.20 +/- 0.05 times larger and its surface gravity is 2.7 +/- 0.2 times weaker. Although it remains the case that HAT-P-1b is among the least dense of the known sample of transiting exoplanets, its properties are in accord with previously published models of strongly irradiated, coreless, solar-composition giant planets. The times of the transits have a typical accuracy of 1 min and do not depart significantly from a constant period.Comment: To appear in AJ [19pg, 3 figures]. New co-author added. Minor revisions to match published versio

    Randomized Efficacy Trial of a Micronutrient-Fortified Beverage in Primary School Children in Tanzania.

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    Dietary supplements providing physiologic amounts of several micronutrients simultaneously have not been thoroughly tested for combating micronutrient deficiencies. We determined whether a beverage fortified with 10 micronutrients at physiologic doses influenced the iron and vitamin A status and growth of rural children (aged 6-11 y) attending primary schools. In this randomized, double-blind, placebo-controlled efficacy trial, children were assigned to receive the fortified beverage or an unfortified beverage at school for 6 mo. There were nonsignificant differences at baseline between children in the fortified and nonfortified groups in iron status, serum retinol, and anthropometry. At the 6-mo follow-up, among children with anemia (hemoglobin < 110 g/L), there was a significantly larger increase in hemoglobin concentration in the fortified group than in the nonfortified group (9.2 and 0.2 g/L, respectively). Of those who were anemic at baseline, 69.4% in the nonfortified group and 55.1% in the fortified group remained anemic at follow-up (RR: 0.79), a cure rate of 21%. The prevalence of children with low serum retinol concentrations (< 200 microg/L) dropped significantly from 21.4% to 11.3% in the fortified group compared with a nonsignificant change (20.6% to 19.7%) in the nonfortified group. At follow-up, mean incremental changes in weight (1.79 compared with 1.24 kg), height (3.2 compared with 2.6 cm), and BMI (0.88 compared with 0.53) were significantly higher in the fortified group than in the nonfortified group. The fortified beverage significantly improved hematologic and anthropometric measurements and significantly lowered the overall prevalence of anemia and vitamin A deficiency

    Discovery and Precise Characterization by the MEarth Project of LP 661-13, an Eclipsing Binary Consisting of Two Fully Convective Low-mass Stars

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    We report the detection of stellar eclipses in the LP 661-13 system. We present the discovery and characterization of this system, including high resolution spectroscopic radial velocities and a photometric solution spanning two observing seasons. LP 661-13 is a low mass binary system with an orbital period of 4.70435120.0000010+0.00000134.7043512^{+0.0000013}_{-0.0000010} days at a distance of 24.9±1.324.9 \pm 1.3 parsecs. LP 661-13A is a 0.30795±0.000840.30795 \pm 0.00084 MM_\odot star while LP 661-13B is a 0.19400±0.000340.19400 \pm 0.00034 MM_\odot star. The radius of each component is 0.3226±0.00330.3226 \pm 0.0033 RR_\odot and 0.2174±0.00230.2174 \pm 0.0023 RR_\odot, respectively. We detect out of eclipse modulations at a period slightly shorter than the orbital period, implying that at least one of the components is not rotating synchronously. We find that each component is slightly inflated compared to stellar models, and that this cannot be reconciled through age or metallicity effects. As a nearby eclipsing binary system where both components are near or below the full-convection limit, LP 661-13 will be a valuable test of models for the structure of cool dwarf stars.Comment: 24 pages, 8 tables, 6 figures. Submitted to ApJ, comments welcom

    Qatar-2: A K dwarf orbited by a transiting hot Jupiter and a more massive companion in an outer orbit

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    We report the discovery and initial characterization of Qatar-2b, a hot Jupiter transiting a V = 13.3 mag K dwarf in a circular orbit with a short period, P_ b = 1.34 days. The mass and radius of Qatar-2b are M_p = 2.49 M_j and R_p = 1.14 R_j, respectively. Radial-velocity monitoring of Qatar-2 over a span of 153 days revealed the presence of a second companion in an outer orbit. The Systemic Console yielded plausible orbits for the outer companion, with periods on the order of a year and a companion mass of at least several M_j. Thus Qatar-2 joins the short but growing list of systems with a transiting hot Jupiter and an outer companion with a much longer period. This system architecture is in sharp contrast to that found by Kepler for multi-transiting systems, which are dominated by objects smaller than Neptune, usually with tightly spaced orbits that must be nearly coplanar
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