43,348 research outputs found
From meson-nucleon scattering to vector mesons in nuclear matter
We employ meson-nucleon scattering data to deduce the properties of the
low-mass vector mesons in nuclear matter, and present results for the
and in-medium spectral functions. The corresponding thermal emission
rate for lepton pairs is also discussed.Comment: Talk given at 28th International Workshop on Gross Properties of
Nuclei and Nuclear Excitations, Hirschegg, Austria, 16-22 Jan. 200
Analysis of Dilepton Invariant Mass Spectrum in C+C at 2 and 1 AGeV
Recently the HADES collaboration has published the invariant mass spectrum of
pairs, dN/dM, produced in C+C collisions at 2 AGeV. Using
electromagnetic probes, one hopes to get in this experiment information on
hadron properties at high density and temperature. Simulations show that firm
conclusions on possible in-medium modifications of meson properties will only
be possible when the elementary meson production cross sections, especially in
the pn channel, as well as production cross sections of baryonic resonances are
better known. Presently one can conclude that a) simulations overpredict by far
the cross section at if free production
cross sections are used and that b) the upper limit of the decay into
is smaller than the present upper limit of the Particle Data Group.
This is the result of simulations using the Isospin Quantum Molecular Dynamics
(IQMD) approach.Comment: 28 pages, 15 figures, 3 tables, ps file recommende
Linearisable third order ordinary differential equations and generalised Sundman transformations
We calculate in detail the conditions which allow the most general third
order ordinary differential equation to be linearised in X'''(T)=0 under the
transformation X(T)=F(x,t), dT=G(x,t)dt. Further generalisations are
considered.Comment: 33 page
Review and evaluation of past solar cell development efforts
Bibliography on photovoltaic effect and solar cell developmen
Review and evaluation of past solar cell development efforts Semiannual report, Jun. 1 - Nov. 30, 1967
Historical review of scientific work on photovoltaic effects and on energy conversion devices using this effec
Establishment of pluripotent cell lines from vertebrate species - Present status and future prospects
Pluripotent embryonic stem (ES) cells are undifferentiated cell lines derived from early embryos and are capable of unlimited undifferentiated proliferation in vitro. They retain the ability to differentiate into all cell types including germ cells in chimeric animals in vivo, and can be induced to form derivatives of all three germ layers in vitro. Mouse ES cells represent one of the most important tools in genetic research. Major applications include the targeted mutation of specific genes by homologous recombination and the discovery of new genes by gene trap strategies. These applications would be of high interest for other model organisms and also for livestock species, However, in spite of tremendous research activities, no proven ES cells colonizing the germ line have been established for vertebrate species other than mouse a nd chicken thus far. This review summarizes the current status of deriving pluripotent embryonic stem cell lines from vertebrates and recent developments in nuclear transfer technology, which may provide an alternative tool for genetic modification of livestock animals. Copyright (C) 1999 S. Karger AG, Basel
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