996 research outputs found
The Demographics of Georgia IV: Hispanic Immigration Economic Policy Issues - Brief
This report analyzes the economic policy issues in education, health care, the labor market, financial services and the fiscal impact arising from the large increase in Hispanic immigration in Georgia. FRC Brief 12
The Demographics of Georgia IV: Hispanic Immigration Economic Policy Issues
This report analyzes the economic policy issues in education, health care, the labor market, financial services and the fiscal impact arising from the large increase in Hispanic immigration in Georgia. FRC Report 12
AGN and their host galaxies in the local Universe: two mass independent Eddington ratio distribution functions characterize black hole growth
We use a phenomenological model to show that black hole growth in the local
Universe (z < 0.1) can be described by two separate, mass independent Eddington
ratio distribution functions (ERDFs). We assume that black holes can be divided
into two independent groups: those with radiatively efficient accretion,
primarily hosted by optically blue and green galaxies, and those with
radiatively inefficient accretion, which are mainly found in red galaxies. With
observed galaxy stellar mass functions as input, we show that the observed AGN
luminosity functions can be reproduced by using mass independent, broken power
law shaped ERDFs. We use the observed hard X-ray and 1.4 GHz radio luminosity
functions to constrain the ERDF for radiatively efficient and inefficient AGN,
respectively. We also test alternative ERDF shapes and mass dependent models.
Our results are consistent with a mass independent AGN fraction and AGN hosts
being randomly drawn from the galaxy population. We argue that the ERDF is not
shaped by galaxy-scale effects, but by how efficiently material can be
transported from the inner few parsecs to the accretion disc. Our results are
incompatible with the simplest form of mass quenching where massive galaxies
host higher accretion rate AGN. Furthermore, if reaching a certain Eddington
ratio is a sufficient condition for maintenance mode, it can occur in all red
galaxies, not just the most massive ones.Comment: 33 pages, 15 figures, accepted for publication in ApJ, Fig. 6 shows
the main resul
Substantial urinary concentrations of material resembling beta-core fragment of chorionic gonadotropin beta-subunit in mid-menstrual cycle
We measured the day-to-day variations in concentrations of beta-core, luteinizing hormone (LH), and alpha-subunit in urine during the menstrual cycle. The alpha-subunit concentrations showed a pattern similar to that of the LH concentrations. beta-Core-like material was increased during and up to 3 to 4 days after the surge in urine LH. The urine LH concentration was associated with the presence of beta-core immunoreactivity during the urine LH peak. Chromatography showed that, at the peak LH concentration and at 2 days after the LH peak, beta-core immunoreactivity could be accounted for by the presence of a peptide of low molecular mass similar to the beta-core molecule of hCG, but probably originating from the degradation of LH. The prolonged excretion of gonadotropin metabolites in the midcycle must be considered when beta-core is being assessed as a tumor marker
Pseudo-Schwarzschild Spherical Accretion as a Classical Black Hole Analogue
We demonstrate that a spherical accretion onto astrophysical black holes,
under the influence of Newtonian or various post-Newtonian pseudo-Schwarzschild
gravitational potentials, may constitute a concrete example of classical
analogue gravity naturally found in the Universe. We analytically calculate the
corresponding analogue Hawking temperature as a function of the minimum number
of physical parameters governing the accretion flow. We study both the
polytropic and the isothermal accretion. We show that unlike in a general
relativistic spherical accretion, analogue white hole solutions can never be
obtained in such post-Newtonian systems. We also show that an isothermal
spherical accretion is a remarkably simple example in which the only one
information--the temperature of the fluid, is sufficient to completely describe
an analogue gravity system. For both types of accretion, the analogue Hawking
temperature may become higher than the usual Hawking temperature. However, the
analogue Hawking temperature for accreting astrophysical black holes is
considerably lower compared with the temperature of the accreting fluid.Comment: Final Version to appear in the journal General Relativity &
Gravitation, Volume 27, Issue 11, 2005. 17 pages, Two colour and one black
and white figures. Typos corrected. Recent reference on analogue effect in
relativistic accretion disc adde
Superluminal pions in a hadronic fluid
We study the propagation of pions at finite temperature and finite chemical
potential in the framework of the linear sigma model with 2 quark flavors and
colors. The velocity of massless pions in general differs from that of
light. One-loop calculations show that in the chiral symmetry broken phase
pions, under certain conditions, propagate faster than light.Comment: 8 pages, 3 figures included. Considerably revised, discussions
expanded, one figure added, typos corrected, results unchanged. To be
published in Phys. Rev.
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