2,728 research outputs found
Population Changes Associated with Net Out-migration from South Dakota Counties, 1950-1960
The central objective of this thesis is to study the relationship between net out-migration and changes in selected characteristics of the population of South Dakota, during the decade from 1950 to 1960. This basic objective can be refined into three minor objectives.
1) To analyze the relationship, if any, between net out-migration rates and changes in selected vital rates of South Dakota\u27s population, by county, for the decade 1950 to 1960.
2) To analyze the relationship, if any, between net out-migration rates and changes in selected demographic characteristics of South Dakota’s population, by county, for the decade 1950 to 1960.
3) To analyze the relationship, if any, between net out-migration rates and changes in selected socioeconomic characteristics of South Dakota\u27s population, by county, for the decade 1950 to 1960
Impact of Neutron Decay Experiments on non-Standard Model Physics
This paper gives a brief overview of the present and expected future limits
on physics beyond the Standard Model (SM) from neutron beta decay, which is
described by two parameters only within the SM. Since more than two observables
are accessible, the problem is over-determined. Thus, precise measurements of
correlations in neutron decay can be used to study the SM as well to search for
evidence of possible extensions to it. Of particular interest in this context
are the search for right-handed currents or for scalar and tensor interactions.
Precision measurements of neutron decay observables address important open
questions of particle physics and cosmology, and are generally complementary to
direct searches for new physics beyond the SM in high-energy physics. Free
neutron decay is therefore a very active field, with a number of new
measurements underway worldwide. We present the impact of recent developments.Comment: 13 pages, 6 figures; Proceedings of the 5th International BEYOND 2010
Conference, Cape Town, South Africa (2010), World Scientific, accepted for
publication; Corrected typo
Neutron Capture Cross Sections for the Weak s Process
In past decades a lot of progress has been made towards understanding the
main s-process component that takes place in thermally pulsing Asymptotic Giant
Branch (AGB) stars. During this process about half of the heavy elements,
mainly between 90<=A<=209 are synthesized. Improvements were made in stellar
modeling as well as in measuring relevant nuclear data for a better description
of the main s process. The weak s process, which contributes to the production
of lighter nuclei in the mass range 56<=A<=90 operates in massive stars
(M>=8Msolar) and is much less understood. A better characterization of the weak
s component would help disentangle the various contributions to element
production in this region. For this purpose, a series of measurements of
neutron-capture cross sections have been performed on medium-mass nuclei at the
3.7-MV Van de Graaff accelerator at FZK using the activation method. Also,
neutron captures on abundant light elements with A<56 play an important role
for s-process nucleosynthesis, since they act as neutron poisons and affect the
stellar neutron balance. New results are presented for the (n,g) cross sections
of 41K and 45Sc, and revisions are reported for a number of cross sections
based on improved spectroscopic information
Selection on feed efficiency in lay hens: direct and correlated response
International audienc
A Spallation Model for the Titanium-rich Supernova Remnant Cassiopeia A
Titanium-rich subluminous supernovae are rare and challenge current SN
nucleosynthesis models. We present a model in which ejecta from a standard
Supernova is impacted by a second explosion of the neutron star (a Quark-nova),
resulting in spallation reactions that lead to 56Ni destruction and 44Ti
creation under the right conditions. Basic calculations of the spallation
products shows that a delay between the two explosions of ~ 5 days reproduces
the observed abundance of 44Ti in Cas A and explains its low luminosity as a
result of the destruction of 56Ni. Our results could have important
implications for lightcurves of subluminous as well as superluminous
supernovae.Comment: Accepted/to be published in Physical Review Letters. [ for more info
on the Quark Nova, see: http://quarknova.ucalgary.ca/
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