573 research outputs found
Long-Range Correlations in Closed Shell Nuclei
The effects of correlations on the bulk properties of nuclei are investigated
in large model spaces including up to 21 single-particle orbits. The evaluation
of the single-particle Green function is made feasible by means of the BAGEL
approximation. The spectral function for single-nucleon pick-up and removal is
investigated for the nuclei and . Special attention is paid
to the effects produced by correlations on the calculated ground state
properties of closed shell nuclei. It is observed that correlations beyond the
Brueckner Hartree Fock approximation tend to improve the results obtained using
realistic nucleon nucleon interactions.Comment: 23 pages 4 figures not included, Report Tu-93-081
Fatty Acid SNP Interaction Analysis in Angus Sired Beef Cattle
The triacylglyceride (TAG) fatty acid content in meat from Angus-sired cattle was analyzed for non-additive genetic effects. A total of 11,482 significant DNA marker interactions (false discovery rate [FDR] \u3c 0.05) were detected across thirty-seven different TAG fatty acids. Interactions were not evenly distributed amongst all fatty acids analyzed, and types of interactions (additive-by-additive, additive-by-dominance, and dominance-by-dominance) varied within each individual fatty acid. These results indicate that it may be possible to account for additional genetic variance amongst TAG fatty acids over and above individual markers
Evaluation of Responses to Vaccination of Angus Cattle for Four Viruses that Contribute to Bovine Respiratory Disease Complex
Initial antibody titers are maternally-derived from colostrum, then decay with age. Change in antibody titer levels were compared between four viruses contributing to the Bovine Respiratory Disease Complex (BRDC), and evaluation of response to vaccination indicated that antibody production will not occur when high levels of maternal antibodies are present. The maternal antibodies were found to decay with calf age for each of the four viruses, which allowed for the estimation of a maximum circulating titer level under which a positive antibody response to vaccination could occur. Phenotypic correlations were calculated between the antibody titers for the four viruses across multiple time points. Results indicate a difference in the response to vaccination between the four virus antigen
'Werner Buttner's Paintings: From 'Werner' to 'Art' and Back Again
Contribution to a monograph on noted German painter Werner Buttner
The response of perennial and temporary headwater stream invertebrate communities to hydrological extremes
The headwaters of karst rivers experience considerable hydrological variability, including spates and streambed drying. Extreme summer flooding on the River Lathkill (Derbyshire, UK) provided the opportunity to examine the invertebrate community response to unseasonal spate flows, flow recession and, at temporary sites, streambed drying. Invertebrates were sampled at sites with differing flow permanence regimes during and after the spates. Following streambed drying at temporary sites, dewatered surface sediments were investigated as a refugium for aquatic invertebrates. Experimental rehydration of these dewatered sediments was conducted to promote development of desiccation-tolerant life stages. At perennial sites, spate flows reduced invertebrate abundance and diversity, whilst at temporary sites, flow reactivation facilitated rapid colonisation of the surface channel by a limited number of invertebrate taxa. Following streambed drying, 38 taxa were recorded from the dewatered and rehydrated sediments, with Oligochaeta being the most abundant taxon and Chironomidae (Diptera) the most diverse. Experimental rehydration of dewatered sediments revealed the presence of additional taxa, including Stenophylax sp. (Trichoptera: Limnephilidae) and Nemoura sp. (Plecoptera: Nemouridae). The influence of flow permanence on invertebrate community composition was apparent despite the aseasonal high-magnitude flood events
The Herschel Exploitation of Local Galaxy Andromeda (HELGA). I: Global far-infrared and sub-mm morphology
We have obtained Herschel images at five wavelengths from 100 to 500 micron
of a ~5.5x2.5 degree area centred on the local galaxy M31 (Andromeda), our
nearest neighbour spiral galaxy, as part of the Herschel guaranteed time
project "HELGA". The main goals of HELGA are to study the characteristics of
the extended dust emission, focusing on larger scales than studied in previous
observations of Andromeda at an increased spatial resolution, and the obscured
star formation. In this paper we present data reduction and Herschel maps, and
provide a description of the far-infrared morphology, comparing it with
features seen at other wavelengths. We use high--resolution maps of the atomic
hydrogen, fully covering our fields, to identify dust emission features that
can be associated to M31 with confidence, distinguishing them from emission
coming from the foreground Galactic cirrus. Thanks to the very large extension
of our maps we detect, for the first time at far-infrared wavelengths, three
arc-like structures extending out to ~21, ~26 and ~31 kpc respectively, in the
south-western part of M31. The presence of these features, hosting ~2.2e6 Msol
of dust, is safely confirmed by their detection in HI maps. Overall, we
estimate a total dust mass of ~5.8e7 Msol, about 78% of which is contained in
the two main ring-like structures at 10 and 15 kpc, at an average temperature
of 16.5 K. We find that the gas-to-dust ratio declines exponentially as a
function of the galacto-centric distance, in agreement with the known
metallicity gradient, with values ranging from 66 in the nucleus to ~275 in the
outermost region. [Abridged]Comment: 15 Pages, 9 Figures. Accepted for publication in Astronomy and
Astrophysics. A high resolution version of the paper can be found at
http://wazn.ugent.be/jfritz/HelgaI_final.pd
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