2,851 research outputs found

    A strong ν¨ν˙\ddot{\nu} - \dot{\nu} correlation in radio pulsars with implications for torque variations

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    We present an analysis of the spin-down parameters for 131 radio pulsars for which ν¨\ddot\nu has been well determined. These pulsars have characteristic ages ranging from 10310810^{3} - 10^{8} yr and spin periods in the range 0.4--30 s; nearly equal numbers of pulsars have ν¨>0\ddot\nu>0 as ν¨<0\ddot\nu<0. We find a strong correlation of ν¨\ddot\nu with ν˙\dot{\nu}, {\em independent of the sign of} ν¨\ddot\nu. We suggest that this trend can be accounted for by small, stochastic deviations in the spin-down torque that are directly proportional (in magnitude) to the spin-down torque.Comment: MNRAS, 4 pages, 2 figures. Minor editorial changes and typos correcte

    Imprints of the QCD Phase Transition on the Spectrum of Gravitational Waves

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    We have investigated effects of the QCD phase transition on the relic GW spectrum applying several equations of state for the strongly interacting matter: Besides the bag model, which describes a first order transition, we use recent data from lattice calculations featuring a crossover. Finally, we include a short period of inflation during the transition which allows for a first order phase transition at finite baryon density. Our results show that the QCD transition imprints a step into the spectrum of GWs. Within the first two scenarios, entropy conservation leads to a step-size determined by the relativistic degrees of freedom before and after the transition. The inflation of the third scenario much stronger attenuates the high-frequency modes: An inflationary model being consistent with observation entails suppression of the spectral energy density by a factor of ~10^(-12).Comment: 11 pages, 13 figure

    Morton, Gould, and Bias: A Comment on The Mismeasure of Science

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    Stephen Jay Gould famously used the work of Samuel George Morton (1799–1851) to illustrate how unconscious racial bias could affect scientific measurement. Morton had published measurements of the average cranial capacities of different races, measurements that Gould reanalyzed in an article in Science [1] and then later in his widely read book The Mismeasure of Man [2]. During the course of this reanalysis, Gould discovered prima facie evidence of unconscious racial bias in Morton’s measurements. More than 30 years later, Lewis et al. published a critique of this analysis [3], denying that Morton’s measurements were biased by his racism. Instead, they claim that their “results falsify Gould’s hypothesis that Morton manipulated his data to conform with his a priori views.” We believe this is mistaken, and our comment will explain why

    Model-Based Assessment of Aspen Responses to Elk Herbivory in Rocky Mountain National Park, USA

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    In Rocky Mountain National Park (RMNP), aspen (Populus tremuloides Michx.) has been observed to be declining on elk (Cervus elaphus nelsoni) winter range for many decades. To support elk management decisions, the SAVANNA ecosystem model was adapted to explore interactions between elk herbivory and aspen dynamics. The simulated probability of successful vegetative regeneration for senescent aspen stands declines sharply when elk densities reach levels of 3-5 elk/km2, depending on model assumptions for the seasonal duration of elk foraging activities. For aspen stands with a substantial component of younger trees, the simulated regeneration probability declines more continuously with increasing elk density, dropping below 50% from densities at 8-14 elk/km2.At the landscape scale, simulated aspen regeneration probability under a scenario of extensive seasonal use was little affected by elk population level, when this level was above 300-600 elk (25%-50% current population) over the ca. 107 km2 winter range. This was because elk distribution was highly aggregated, so that a high density of elk occupied certain areas, even at low population levels overall. At approximately current elk population levels (1000-1200 elk), only 35%-45% of senescent aspen stands are simulated as having at least a 90% probability of regeneration, nearly all of them located on the periphery of the winter range. Successful management for aspen persistence on core winter range will likely require some combination of elk population reduction, management of elk distribution, and fencing to protect aspen suckers from elk browsin

    Arecibo HI Absorption Measurements of Pulsars and the Electron Density at Intermediate Longitudes in the First Galactic Quadrant

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    We have used the Arecibo telescope to measure the HI absorption spectra of eight pulsars. We show how kinematic distance measurements depend upon the values of the galactic constants R_o and Theta_o, and we select our preferred current values from the literature. We then derive kinematic distances for the low-latitude pulsars in our sample and electron densities along their lines of sight. We combine these measurements with all others in the inner galactic plane visible from Arecibo to study the electron density in this region. The electron density in the interarm range 48 degrees < l < 70 degrees is [0.017 (-0.007,+0.012) (68% c.l.)] cm^(-3). This is 0.75 (-0.22,+0.49) (68% c.l.) of the value calculated by the Cordes & Lazio (2002) galactic electron density model. The model agrees more closely with electron density measurements toward Arecibo pulsars lying closer to the galactic center, at 30 degrees<l<48 degrees. Our analysis leads to the best current estimate of the distance of the relativistic binary pulsar B1913+16: d=(9.0 +/- 3) kpc. We use the high-latitude pulsars to search for small-scale structure in the interstellar hydrogen observed in absorption over multiple epochs. PSR B0301+19 exhibited significant changes in its absorption spectrum over 22 yr, indicating HI structure on a ~500 AU scale.Comment: Accepted by Astrophysical Journal September 200

    Probing the size of extra dimension with gravitational wave astronomy

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    In Randall-Sundrum II (RS-II) braneworld model, it has been conjectured according to the AdS/CFT correspondence that brane-localized black hole (BH) larger than the bulk AdS curvature scale \ell cannot be static, and it is dual to a four dimensional BH emitting the Hawking radiation through some quantum fields. In this scenario, the number of the quantum field species is so large that this radiation changes the orbital evolution of a BH binary. We derived the correction to the gravitational waveform phase due to this effect and estimated the upper bounds on \ell by performing Fisher analyses. We found that DECIGO/BBO can put a stronger constraint than the current table-top result by detecting gravitational waves from small mass BH/BH and BH/neutron star (NS) binaries. Furthermore, DECIGO/BBO is expected to detect 105^5 BH/NS binaries per year. Taking this advantage, we found that DECIGO/BBO can actually measure \ell down to =0.33μ\ell=0.33 \mum for 5 year observation if we know that binaries are circular a priori. This is about 40 times smaller than the upper bound obtained from the table-top experiment. On the other hand, when we take eccentricities into binary parameters, the detection limit weakens to =1.5μ\ell=1.5 \mum due to strong degeneracies between \ell and eccentricities. We also derived the upper bound on \ell from the expected detection number of extreme mass ratio inspirals (EMRIs) with LISA and BH/NS binaries with DECIGO/BBO, extending the discussion made recently by McWilliams. We found that these less robust constraints are weaker than the ones from phase differences.Comment: 19 pages, 10 figures. Published in PRD, typos corrected, references and footnotes adde

    Gender Differences in Personality across the Ten Aspects of the Big Five

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    This paper investigates gender differences in personality traits, both at the level of the Big Five and at the sublevel of two aspects within each Big Five domain. Replicating previous findings, women reported higher Big Five Extraversion, Agreeableness, and Neuroticism scores than men. However, more extensive gender differences were found at the level of the aspects, with significant gender differences appearing in both aspects of every Big Five trait. For Extraversion, Openness, and Conscientiousness, the gender differences were found to diverge at the aspect level, rendering them either small or undetectable at the Big Five level. These findings clarify the nature of gender differences in personality and highlight the utility of measuring personality at the aspect level

    The effects of musical structure, musical training, and personal constructs upon perception of music.

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    Dept. of Psychology. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1980 .W458. Source: Masters Abstracts International, Volume: 40-07, page: . Thesis (M.A.)--University of Windsor (Canada), 1980
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