6,313 research outputs found

    On a new species of Squirrel Monkey, Genus Saimiri, from Brazilian AmazĂŽnia (Primates, Cebidae)

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    Measuring the muon's anomalous magnetic moment to 0.14 ppm

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    The anomalous magnetic moment (g-2) of the muon was measured with a precision of 0.54 ppm in Experiment 821 at Brookhaven National Laboratory. A difference of 3.2 standard deviations between this experimental value and the prediction of the Standard Model has persisted since 2004; in spite of considerable experimental and theoretical effort, there is no consistent explanation for this difference. This comparison hints at physics beyond the Standard Model, but it also imposes strong constraints on those possibilities, which include supersymmetry and extra dimensions. The collaboration is preparing to relocate the experiment to Fermilab to continue towards a proposed precision of 0.14 ppm. This will require 20 times more recorded decays than in the previous measurement, with corresponding improvements in the systematic uncertainties. We describe the theoretical developments and the experimental upgrades that provide a compelling motivation for the new measurement.Comment: 5 pages, 1 figure, presented at International Nuclear Physics Conference 2010 (INPC 2010

    51 Pegasi - a planet-bearing Maunder minimum candidate

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    We observed 51 Peg, the first detected planet-bearing star, in a 55 ks XMM-Newton pointing and in 5 ks pointings each with Chandra HRC-I and ACIS-S. The star has a very low count rate in the XMM observation, but is clearly visible in the Chandra images due to the detectors' different sensitivity at low X-ray energies. This allows a temperature estimate for 51 Peg's corona of T<1MK; the detected ACIS-S photons can be plausibly explained by emission lines of a very cool plasma near 200eV. The constantly low X-ray surface flux and the flat-activity profile seen in optical CaII data suggest that 51 Peg is a Maunder minimum star; an activity enhancement due to a Hot Jupiter, as proposed by recent studies, seems to be absent. The star's X-ray fluxes in different instruments are consistent with the exception of the HRC Imager, which might have a larger effective area below 200eV than given in the calibration.Comment: accepted by A&

    Legal Entitlements as Auctions: Property Rules, Liability Rules, and Beyond

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    Solar Carbon Monoxide, Thermal Profiling, and the Abundances of C, O, and their Isotopes

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    A solar photospheric "thermal profiling" analysis is presented, exploiting the infrared rovibrational bands of carbon monoxide (CO) as observed with the McMath-Pierce Fourier transform spectrometer (FTS) at Kitt Peak, and from above the Earth's atmosphere by the Shuttle-borne ATMOS experiment. Visible continuum intensities and center-limb behavior constrained the temperature profile of the deep photosphere, while CO center-limb behavior defined the thermal structure at higher altitudes. The oxygen abundance was self consistently determined from weak CO absorptions. Our analysis was meant to complement recent studies based on 3-D convection models which, among other things, have revised the historical solar oxygen (and carbon) abundance downward by a factor of nearly two; although in fact our conclusions do not support such a revision. Based on various considerations, an oxygen abundance of 700+/-100 ppm (parts per million relative to hydrogen) is recommended; the large uncertainty reflects the model sensitivity of CO. New solar isotopic ratios also are reported for 13C, 17O, and 18O.Comment: 90 pages, 19 figures (some with parts "a", "b", etc.); to be published in the Astrophysical Journal Supplement

    Regulating Scotland's social landlords: localised resistance to technologies of performance management

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    Influenced by Foucault's later work on governmentality, this paper explores the regulation of social landlords as a 'technology of performance' concerned with governing the conduct of dispersed welfare agencies and the professionals within them. This is a mode of power that is both voluntary and coercive; it seeks to realise its ambitions not through direct acts of intervention, but by promoting the responsible self-governance of autonomous subjects. Through an analysis of the regulatory framework for social landlords in Scotland, this paper highlights the creation of a performance culture that seeks to mobilise housing organisations to reconcile their local management systems and service provision to external standards, whilst simultaneously wielding punitive interventions for non-compliance. However, housing professionals are not passive in all of this, and indeed, actively challenged and resisted these top-down attempts to govern them at arm's-length

    Aspectos da caça no alto rio Aripuanã

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    The amount of game killed by hunters in rain forest surrounding Dardanelos (Aripuanã, State of Mato Grosso, Brazil) in southern Amazonia, was recorded from January to april, 1978. White-lipped peccaries (Tayassu pecan), tapirs (Tapirus terrestris), and collared peccaries (Tayassu tajacu), represented 89% of the 8857kg of game killed. Wild moat was an important suplementary protein source, and was present in 19% of the meals. Only four hunters were responsible for over half of the game killed. The demography of the human population, as wel as the local hunting methods, are described and the necessity of conservation of wildlife in this region is discussed.Através de levantamentos entre janeiro e abril de 1978, com toda a população de Durdanelos (Aripuanã-MT) a caça abatida na årea foi determinada. As queixadas (Tayassu pecari), as antas (Tapirus terrestris) e os caititus (Tayassu tajacu) representaram 89% dos 8857 kg de caça abatida neste período. A carne de caça representou uma importante fonte adicional de proteínas e estava presente em 19% das refeiçÔes. Os principais métodos de caça na årea são descritos e a necessidade de conservação da fauna na região discutida

    A far-UV survey of three hot, metal-polluted white dwarf stars: WD0455-282, WD0621-376, and WD2211-495

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    Using newly obtained high-resolution data (R∌1×105R\sim{1\times{10}^{5}}) from the \textit{Hubble Space Telescope}, and archival UV data from the \textit{Far Ultraviolet Spectroscopic Explorer} we have conducted a detailed UV survey of the three hot, metal-polluted white dwarfs WD0455-282, WD0621-376, and WD2211-495. Using bespoke model atmospheres we measured TeffT_{\mathrm{eff}}, log gg, and photospheric abundances for these stars. In conjunction with data from Gaia we measured masses, radii, and gravitational redshift velocities for our sample of objects. We compared the measured photospheric abundances with those predicted by radiative levitation theory, and found that the observed Si abundances in all three white dwarfs, and the observed Fe abundances in WD0621-376 and WD2211-495, were larger than those predicted by an order of magnitude. These findings imply not only an external origin for the metals, but also ongoing accretion, as the metals not supported by radiative levitation would sink on extremely short timescales. We measured the radial velocities of several absorption features along the line of sight to the three objects in our sample, allowing us to determine the velocities of the photospheric and interstellar components along the line of sight for each star. Interestingly, we made detections of circumstellar absorption along the line of sight to WD0455-282 with three velocity components. To our knowledge, this is the first such detection of multi-component circumstellar absorption along the line of sight to a white dwarf.Comment: 19 pages, 23 figures, 8 tables. Accepted for publication in the Monthly Notices of the Royal Astronomical Societ

    The Mg 2 h and k lines in a sample of dMe and dM stars

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    Both Mg II h and k line fluxes are presented for a sample of 4 dMe and 3 dM stars obtained with the IUE satellite in the long wavelength, low dispersion mode. The observed fluxes are converted to stellar surface flux units and the importance of chromospheric non radiative heating in this sample of M dwarf stars is intercompared. In addition, the net chromospheric radiative losses due to the Ca II H and K lines in those stars in the sample for which calibrated Ca II H and K line data exist are compared. Active region filling factors which likely give rise to the observed optical and ultraviolet chromospheric emission are estimated. The implications of the results for homogeneous, single component stellar model chromospheres analyses are discussed
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