1,680 research outputs found
How rapidly do neutron stars spin at birth? Constaints from archival X-ray observations of extragalactic supernovae
Traditionally, studies aimed at inferring the distribution of birth periods of neutron stars are based on radio surveys. Here we propose an independent method to constrain the pulsar spin periods at birth based on their X-ray luminosities. In particular, the observed luminosity distribution of supernovae (SNe) poses a constraint on the initial rotational energy of the embedded pulsars, via the correlation found for radio pulsars, and under the assumption that this relation continues to hold beyond the observed range. We have extracted X-ray luminosities (or limits) for a large sample of historical SNe observed with Chandra, XMM and Swift, which have been firmly classified as core-collapse SNe. We have then compared these observational limits with the results of Monte Carlo simulations of the pulsar X-ray luminosity distribution for a range of values of the birth parameters. We find that a pulsar population dominated by millisecond periods at birth is ruled out by the data
A āNot Particularly Felicitousā Phrase: A History of the āBehavioral Sciencesā Label
The article reconstructs the history of the "behavioral sciences" label, from scattered interwar use through to the decisive embrace of the newly prominent Ford Foundation in the early Cold War. The rapid uptake of the label, the article concludes, was the result of the Ford Foundationās 1951 decision to name its social science unit the āBehavioral Sciences Programā (BSP). With Fordās encouragement, the term was widely adopted by quantitative social scientists eager to tap the foundationās social science funds. The labelās newness and its link to the gigantic foundationās initiative generated much suspicion and resistance as well
Interface Width and Bulk Stability: requirements for the simulation of Deeply Quenched Liquid-Gas Systems
Simulations of liquid-gas systems with extended interfaces are observed to
fail to give accurate results for two reasons: the interface can get ``stuck''
on the lattice or a density overshoot develops around the interface. In the
first case the bulk densities can take a range of values, dependent on the
initial conditions. In the second case inaccurate bulk densities are found. In
this communication we derive the minimum interface width required for the
accurate simulation of liquid gas systems with a diffuse interface. We
demonstrate this criterion for lattice Boltzmann simulations of a van der Waals
gas. When combining this criterion with predictions for the bulk stability we
can predict the parameter range that leads to stable and accurate simulation
results. This allows us to identify parameter ranges leading to high density
ratios of over 1000. This is despite the fact that lattice Boltzmann
simulations of liquid-gas systems were believed to be restricted to modest
density ratios of less than 20.Comment: 5 pages, 3 figure
The psychological benefits of participating in group singing for members of the general public
The last decade has produced a growing number of studies examining the potential psychological benefits of singing in a choir. Studies have tended to focus on the benefits for groups that might be described as marginalized or criminal. In contrast, the current study focused on members of the general public who regularly participate in choral singing. An in-depth qualitative design was utilized to explore the meaning and importance of group singing for 10 participants. Thematic analysis based on an interpretive approach was utilized to analyse the data. Psychological benefits emerged as two themes: individual and group. A third theme, mediating factors, impacted upon both individual and group outcomes. Eight sub-themes were identified and labelled: psychological, musical, physical, ethos, group dynamic, past experiences, type of choir and musical director. Results illustrate that group singing is a joyful activity that promotes wellbeing and is life enhancing for those involved. Future research directions are briefly discussed
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