22,976 research outputs found
Voices From the Street: A Survey of Homeless Youth by Their Peers
Summarizes interviews of homeless or formerly homeless youth by their peers about how they became homeless, their lives on the street, interactions with police, education, aspirations, mental health, support networks, services, and policy suggestions
Sudden approximation applied to rotational excitation of molecules by atoms. ii- scat- tering of polar diatomics
Sudden approximation applied to computation of rotational transition probability and inelastic total cross sections for scattering of polar and nonpolar diatomic molecules by atom
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Converting three-space matrices to equivalent six-space matrices for Delone scalars in S6.
The transformations from the primitive cells of the centered Bravais lattices to the corresponding centered cells have conventionally been listed as three-by-three matrices that transform three-space lattice vectors. Using those three-by-three matrices when working in the six-dimensional space of lattices represented as Selling scalars as used in Delone (Delaunay) reduction, one could transform to the three-space representation, apply the three-by-three matrices and then back-transform to the six-space representation, but it is much simpler to have the equivalent six-by-six matrices and apply them directly. The general form of the transformation from the three-space matrix to the corresponding matrix operating on Selling scalars (expressed in space S6) is derived, and the particular S6matrices for the centered Delone types are listed. (Note: in his later publications, Boris Delaunay used the Russian version of his surname, Delone.)
Cosmic Optical Background: the View from Pioneer 10/11
We present the new constraints on the cosmic optical background (COB)
obtained from an analysis of the Pioneer 10/11 Imaging Photopolarimeter (IPP)
data. After careful examination of data quality, the usable measurements free
from the zodiacal light are integrated into sky maps at the blue (~0.44 um) and
red (~0.64 um) bands. Accurate starlight subtraction is achieved by referring
to all-sky star catalogs and a Galactic stellar population synthesis model down
to 32.0 mag. We find that the residual light is separated into two components:
one component shows a clear correlation with thermal 100 um brightness, while
another betrays a constant level in the lowest 100 um brightness region.
Presence of the second component is significant after all the uncertainties and
possible residual light in the Galaxy are taken into account, thus it most
likely has the extragalactic origin (i.e., the COB). The derived COB brightness
is (1.8 +/- 0.9) x 10^(-9) and (1.2 +/- 0.9) x 10^(-9) erg/s/cm2/sr/A at the
blue and red band, respectively, or 7.9 +/- 4.0 and 7.7 +/- 5.8 nW/m2/sr. Based
on a comparison with the integrated brightness of galaxies, we conclude that
the bulk of the COB is comprised of normal galaxies which have already been
resolved by the current deepest observations. There seems to be little room for
contributions of other populations including "first stars" at these
wavelengths. On the other hand, the first component of the IPP residual light
represents the diffuse Galactic light (DGL) - scattered starlight by the
interstellar dust. We derive the mean DGL-to-100 um brightness ratios of 2.1 x
10^(-3) and 4.6 x 10^(-3) at the two bands, which are roughly consistent with
the previous observations toward denser dust regions. Extended red emission in
the diffuse interstellar medium is also confirmed.Comment: Accepted for publication in the Astrophysical Journal; Typos
correcte
Electroweak interactions in a relativistic Fermi gas
We present a relativistic model for computing the neutrino mean free path in
neutron matter. Thereby, neutron matter is described as a non-interacting Fermi
gas in beta-equilibrium. We present results for the neutrino mean free path for
temperatures from 0 up to 50 MeV and a broad range of neutrino energies. We
show that relativistic effects cause a considerable enhancement of
neutrino-scattering cross-sections in neutron matter. The influence of the
-dependence in the electroweak form factors and the inclusion of a weak
magnetic term in the hadron current is discussed. The weak-magnetic term in the
hadron current is at the origin of some selective spin dependence for the
nucleons which are subject to neutrino interactions.Comment: 11 pages, 7 figures, accepted to Phys. Rev. C, minor changes and
updates of the figures are mad
Composition is not research
Copyright © Cambridge University Press 2015Composers in academic institutions are increasingly required to describe their activities in terms of 'research ' - formulating 'research questions', 'research narratives', 'aims' and 'outcomes'. Research plans and funding applications require one to specify the nature of the original contribution that will be made by a piece of music, even before it is composed. These requirements lead to an emphasis on collaborative work, technology and superficial novelty of format. Yet the very idea that musical composition is a form of research is a category error: music is a domain of thought whose cognitive dimension lies in embodiment, revelation or presentation, but not in investigation and description. It is argued here that the idea of composition as research is not only objectively false but inimical to genuine musical originality
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