232 research outputs found
Fock Representations of Quantum Fields with Generalized Statistic
We develop a rigorous framework for constructing Fock representations of
quantum fields obeying generalized statistics associated with certain solutions
of the spectral quantum Yang-Baxter equation. The main features of these
representations are investigated. Various aspects of the underlying
mathematical structure are illustrated by means of explicit examples.Comment: 26 pages, Te
Natural Color Transparency in High Energy (p,pp) Reactions
New parameter free calculations including a variety of necessary kinematic
and dynamic effects show that the results of BNL measurements are
consistent with the expectations of color transparency.Comment: latex file, 13 pages, 4 figures appended as ps files, look for "cut
here ..." 1993 Univ. of Washington preprint 404427-00-N93-1
Searching for Color Coherent Effects at Intermediate via Double Scattering Processes
We propose that measuring the dependence of the number of final-state
interactions of the recoil protons in quasi-elastic electron scattering from
light nuclei is a new method to investigate Color Coherent effects at {\bf
intermediate} values of ({ few }). This is instead of
measuring events without final-state interactions. Our calculations indicate
that such measurements could reveal significant color transparency effects for
the highest of the energies initially available at CEBAF. Measurements that
detect more than one hadron in the final state, which require the use of large
acceptance () detectors, are required.Comment: 19 pages in RevTex, 5 postscript figures available from
[email protected]
Rare-Earth Nuclei: Radii, Isotope-Shifts and Deformation Properties in the Relativistic Mean Field Theory
A systematic study of the ground-state properties of even-even rare earth
nuclei has been performed in the framework of the Relativistic Mean-Field (RMF)
theory using the parameter set NL-SH. Nuclear radii, isotope shifts and
deformation properties of the heavier rare-earth nuclei have been obtained,
which encompass atomic numbers ranging from Z=60 to Z=70 and include a large
range of isospin. It is shown that RMF theory is able to provide a good and
comprehensive description of the empirical binding energies of the isotopic
chains. At the same time the quadrupole deformations obtained in
the RMF theory are found to be in good agreement with the available empirical
values. The theory predicts a shape transition from prolate to oblate for
nuclei at neutron number N=78 in all the chains. A further addition of neutrons
up to the magic number 82 brings about the spherical shape. For nuclei above
N=82, the RMF theory predicts the well-known onset of prolate deformation at
about N=88, which saturates at about N=102. The deformation properties display
an identical behaviour for all the nuclear chains. A good description of the
above deformation transitions in the RMF theory in all the isotopic chains
leads to a successful reproduction of the anomalous behaviour of the empirical
isotopic shifts of the rare-earth nuclei. The RMF theory exhibits a remarkable
success in providing a unified and microscopic description of various empirical
data.Comment: Revtex (50 pages) and 24 figures (available upon request), Nuclear
Physics A (in press
Grain Surface Models and Data for Astrochemistry
AbstractThe cross-disciplinary field of astrochemistry exists to understand the formation, destruction, and survival of molecules in astrophysical environments. Molecules in space are synthesized via a large variety of gas-phase reactions, and reactions on dust-grain surfaces, where the surface acts as a catalyst. A broad consensus has been reached in the astrochemistry community on how to suitably treat gas-phase processes in models, and also on how to present the necessary reaction data in databases; however, no such consensus has yet been reached for grain-surface processes. A team of ∼25 experts covering observational, laboratory and theoretical (astro)chemistry met in summer of 2014 at the Lorentz Center in Leiden with the aim to provide solutions for this problem and to review the current state-of-the-art of grain surface models, both in terms of technical implementation into models as well as the most up-to-date information available from experiments and chemical computations. This review builds on the results of this workshop and gives an outlook for future directions
Synaptic processes and immune-related pathways implicated in Tourette syndrome.
Tourette syndrome (TS) is a neuropsychiatric disorder of complex genetic architecture involving multiple interacting genes. Here, we sought to elucidate the pathways that underlie the neurobiology of the disorder through genome-wide analysis. We analyzed genome-wide genotypic data of 3581 individuals with TS and 7682 ancestry-matched controls and investigated associations of TS with sets of genes that are expressed in particular cell types and operate in specific neuronal and glial functions. We employed a self-contained, set-based association method (SBA) as well as a competitive gene set method (MAGMA) using individual-level genotype data to perform a comprehensive investigation of the biological background of TS. Our SBA analysis identified three significant gene sets after Bonferroni correction, implicating ligand-gated ion channel signaling, lymphocytic, and cell adhesion and transsynaptic signaling processes. MAGMA analysis further supported the involvement of the cell adhesion and trans-synaptic signaling gene set. The lymphocytic gene set was driven by variants in FLT3, raising an intriguing hypothesis for the involvement of a neuroinflammatory element in TS pathogenesis. The indications of involvement of ligand-gated ion channel signaling reinforce the role of GABA in TS, while the association of cell adhesion and trans-synaptic signaling gene set provides additional support for the role of adhesion molecules in neuropsychiatric disorders. This study reinforces previous findings but also provides new insights into the neurobiology of TS
Genetic, abiotic and social influences on sex differentiation in cichlid fishes and the evolution of sequential hermaphroditism
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73799/1/j.1467-2979.2005.00184.x.pd
Larval density, temperature and biological aspects of Chrysomya megacephala (Diptera: Calliphoridae)
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