5,163 research outputs found
ASCA observations of the galactic bulge hard x-ray source GRS 1758--258
GRS 1758-258 is one of the few persistent hard X-ray emitters (E>100 keV) in
the Galaxy. Using the ASCA satellite, we have obtained the first detailed data
on GRS 1758-258 in the 1-10 keV range, where previous observations were
affected by confusion problems caused by the nearby strong source GX5-1. The
spectrum is well described by a power law with photon index 1.7 without strong
Fe emission lines. A prominent soft excess, as observed with ROSAT when the
hard X-ray flux was in a lower intensity state, was not detected. However, the
presence of a soft spectral component, accounting for at most 5% of the 0.1-300
keV flux, cannot be excluded. The accurate measurement of interstellar
absorption (N_H=(1.5+-0.1) x 10^22 cm -2) corresponds to an optical extinction
which definitely excludes the presence of a massive companion.Comment: 7 pages, AAS latex [11pt,aaspptwo,flushrt,tighten], + 1.ps figure
Accepted for pubblication in ApJ, 09 02 96 Also available at
http://fy.chalmers.se/~haardt/personal/curr.html Figures 1 and 2 available
upon request at [email protected]
Gauge/gravity duality and the interplay of various fractional branes
We consider different types of fractional branes on a Z_2 orbifold of the
conifold and analyze in detail the corresponding gauge/gravity duality. The
gauge theory possesses a rich and varied dynamics, both in the UV and in the
IR. We find the dual supergravity solution which contains both untwisted and
twisted 3-form fluxes, related to what are known as deformation and N=2
fractional branes respectively. We analyze the resulting RG flow from the
supergravity perspective, by developing an algorithm to easily extract it. We
find hints of a generalization of the familiar cascade of Seiberg dualities due
to a non-trivial interplay between the different types of fractional branes. We
finally consider the IR behavior in several limits, where the dominant
effective dynamics is either confining, in a Coulomb phase or runaway, and
discuss the resolution of singularities in the dual geometric background.Comment: 38 pages + appendices, 15 figures; v2: refs added and typos correcte
Platelet Rich Plasma for Regenerative Medicine Treatment of Bovine Ovarian Hypofunction
Recent studies on cull cows have shown that ovarian abnormalities, particularly ovarian insufficiency, are the main cause of reproductive failure. The aim of this study was to treat bovine ovarian failure with intraovarian administration of autologous platelet rich plasma (PRP), which is rich in growth factors, chemokines, and cytokines that could stimulate follicular growth and steroidogenesis. Twelve cows with ovarian hypofunction were enrolled in the study and they were randomly allocated in control group (CTR) and treated group (six animal for group). In the treated group, only five animals received the PRP treatment because intraovarian administration was hindered in one by a rectovaginal fistula. Animals of control group were treated by intraovarian administration of physiological solution. In the 4 weeks after PRP injection, a mild to strong increase in progesterone (PRG) concentrations was detected in four of the five cows treated. Artificial insemination (AI) resulted in four pregnancies that are still ongoing (7th month). Intraovarian administration of PRP improved ovarian function after 2 months of treatment. This effect may be due to reduction of follicular atresia or to revitalization of dormant oocytes allowing restoration of fertility
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