1,114 research outputs found
A few comments on the high-energy behavior of string scattering amplitudes in warped spacetimes
The high-energy behavior of string scattering in warped spacetimes is studied
to all orders in perturbation theory. If one assumes that the theory is finite,
the amplitudes exactly fall as powers of momentum.Comment: 6 page
Types of Angiopathy in Experimental Autoimmune Disease in Rats
The purpose and objectives of this work were to study the nature of the heart, lungs and kidneys angiopathy in rats with a model of systemic autoimmune disease, carrying out comparisons of the results with extravasal morphological manifestations of the pathological process, the state of vascular endothelial function and activity of pro-inflammatory cytokines in the blood. The experiment was conducted on 40 non-linear rats. To simulate the disease animals were injected by complete Freund's adjuvant, a solution of splenic deoxyribonucleic acid cattle, mercaptopurine, methyluracilum and with food rats constantly received sulfate cadmium, lithium hydroxybutyrate and ammonium molybdate. Within two months from the start of the study animals were taken out of the experiment on the background of intraperitoneal nembutal anesthesia. Histological sections of the heart, lung and kidney tissue were stained with hematoxylin -eosin, alcian blue and by van-Gieson, becoming the PAS-reaction. In the animals with the proposed experimental model of systemic autoimmune disease observed morphological characteristics of lesions of the heart blood vessels, lungs and kidneys, the nature of the manifestations of which were interconnected with each other, which confirms the common pathogenetic angiopathy constructions at various diseases in clinical practice. In the genesis of cardiac, pulmonary and renal vessels lesions act the activation of pro-inflammatory cytokines and violation of vascular endothelial function, which has a certain practical significance. In clinical practice, not only purely systemic vasculitis, and other autoimmune diseases should be treated as angiopathy
Fluctuations of the Fermi condensate in ideal gases
We calculate numerically and analytically the fluctuations of the fermionic
condensate and of the number of particles above the condensate for systems of
constant density of states. We compare the canonical fluctuations, obtained
from the equivalent Bose condensate fluctuation, with the grandcanonical
fermionic calculation. The fluctuations of the condensate are almost the same
in the two ensembles, with a small correction comming from the total particle
number fluctuation in the grandcanonical ensemble. On the other hand the number
of particles above the condensate and its fluctuation is insensitive to the
choice of ensemble.Comment: 10 pages with 3 figs. IOP styl
GRANAT/WATCH catalogue of cosmic gamma-ray bursts: December 1989 to September 1994
We present the catalogue of gamma-ray bursts observed with the WATCH all-sky
monitor on board the GRANAT satellite during the period December 1989 to
September 1994. The cosmic origin of 95 bursts comprising the catalogue is
confirmed either by their localization with WATCH or by their detection with
other GRB experiments. For each burst its time history and information on its
intensity in the two energy ranges 8-20 keV and 20-60 keV are presented. Most
events show hardening of the energy spectrum near the burst peak. In part of
the bursts an X-ray precursor or a tail is seen at 8-20 keV. We have determined
the celestial positions of the sources of 47 bursts. Their localization regions
(at 3-sigma confidence level) are equivalent in area to circles with radii
ranging from 0.2 to 1.6 deg. The burst sources appear isotropically distributed
on the sky on large angular scales.Comment: 18 pages (including 3 tables and 7 figures), LaTeX, l-aa style.
Accepted by Astronomy and Astrophysics Suppl. Serie
Tidal Effects in Clusters of Galaxies
High-redshift clusters of galaxies show an over-abundance of spirals by a
factor of 2-3, and the corresponding under-abundance of S0 galaxies, relative
to the nearby clusters. This morphological evolution can be explained by tidal
interactions with neighboring galaxies and with the hierarchically growing
cluster halo. The efficiency of tidal interactions depends on the size and
structure of the cluster, as well as on the epoch of its formation. I simulate
the formation and evolution of Virgo-type clusters in three cosmologies: a
critical density model Omega_0=1, an open model Omega_0=0.4, and a flat model
Omega_0=0.4 with a cosmological constant. The orbits of identified halos are
traced with a high temporal resolution (~10^7 yr). Halos with low relative
velocities merge only shortly after entering the cluster; after virialization
mergers are suppressed. The dynamical evolution of galaxies is determined by
the tidal field along their trajectories. The maxima of the tidal force do not
always correspond to closest approach to the cluster center. They are produced
to a large extent by the local density structures, such as the massive galaxies
and the unvirialized remnants of infalling groups of galaxies. Collisions of
galaxies are intensified by the substructure, with about 10 encounters within
10 kpc per galaxy in the Hubble time. These very close encounters add an
important amount (10-50%) of the total heating rate. The integrated effect of
tidal interactions is insufficient to transform a spiral galaxy into an
elliptical, but can produce an S0 galaxy. Overall, tidal heating is stronger in
the low Omega_0 clusters
Ash and Slag Waste as a Secondary Raw Material
In the process of industrial corporation activities a lot of waste, which pollutes the atmosphere, is generated, for example ash and slag. In Tomsk region, by estimates, ash stores occupy about 600 hectares, which contain about 25 million tons by weight. In Russian thermal power-stations ash disposal areas there are about 1.3 billion tons of ash, and only 10% of it is used. That is why this problem is topical enough. In this paper the scheme of producing ash ceramic bricks and complex ash and slag waste processing is shown. Besides, profitability of the project is presented
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