2,641 research outputs found
Isospectral pairs of metrics on balls, spheres, and other manifolds with different local geometries
The first isospectral pairs of metrics are constructed on balls and spheres.
This long standing problem, concerning the existence of such pairs, has been
solved by a new method called "Anticommutator Technique." Among the wide range
of such pairs, the most striking examples are provided on (4k-1)-dimensional
spheres, where k > 2. One of these metrics is homogeneous (since it is the
metric on the geodesic sphere of a 2-point homogeneous space), while the other
is locally inhomogeneous. These examples demonstrate the surprising fact that
no information about the isometries is encoded in the spectrum of Laplacian
acting on functions. In other words, "The group of isometries, even the local
homogeneity property, is lost to the "Non-Audible" in the debate of "Audible
versus Non-Audible Geometry"."Comment: 43 pages. After retrieving source, read README file or type tex whole
to typeset (in Unix
Involvement of Nitric Oxide in Microcirculatory Reactions after Ischemia-Reperfusion of the Rat Urinary Bladder
Background: Nitric oxide ( NO) plays a role in inflammation. Our aim was to investigate the role of NO in the microcirculatory changes after ischemia-reperfusion (I/R) of the bladder using intravital videomicroscopy (IVM). Methods: In rats, 60 min of bladder ischemia followed by 30 min of reperfusion was performed in the presence of N(G)-nitro-L-arginine methyl ester (L-NAME), the NO precursor L-arginine, or saline pre-treatments. Venular red blood cell velocity (RBCV), functional capillary density (FCD), vessel diameters, and leukocyte-endothelial cell interactions in postcapillary venules were determined. Concentrations of nitrite/nitrate in the plasma and myeloperoxidase (MPO) levels in the lungs and the bladder were measured. Results: Elevations of the numbers of rolling and adherent leukocytes, and of plasma nitrite/nitrate levels were found, while FCD and RBCV decreased. L-NAME pretreatment ameliorated the enhanced leukocyte-endothelial cell interactions without influencing the microcirculatory perfusion. In contrast, the L - arginine pretreatment further increased plasma nitrite/nitrate levels and preserved the FCD and RBCV, but did not affect leukocyte-endothelial interactions. None of these treatments influenced MPO activities. Conclusion: Our results suggest that NO plays an enhancing role in the I/R-induced neutrophil-endothelial interactions of the bladder. Supplementation of NO ameliorates the microcirculatory perfusion deficit without influencing the postischemic microcirculatory inflammatory reactions. Copyright (c) 2008 S. Karger AG, Base
Lattice QCD at non-vanishing density: phase diagram, equation of state
We propose a method to study lattice QCD at non-vanishing temperature (T) and
chemical potential (\mu). We use n_f=2+1 dynamical staggered quarks with
semi-realistic masses on L_t=4 lattices. The critical endpoint (E) of QCD on
the Re(\mu)-T plane is located. We calculate the pressure (p), the energy
density (\epsilon) and the baryon density (n_B) of QCD at non-vanishing T and
\mu.Comment: Contributed to Workshop on Strong and Electroweak Matter (SEWM 2002),
Heidelberg, Germany, 2-5 Oct 200
The QCD equation of state at finite T/\mu on the lattice
We present N_t=4 lattice results for the equation of state of 2+1 flavour
staggered, dynamical QCD at finite temperature and chemical potential. We use
the overlap improving multi-parameter reweighting technique to extend the
equation of state for non-vanishing chemical potentials. The results are
obtained along the line of constant physics. Our physical parameters extend in
temperature and baryon chemical potential upto \approx 500-600 MeV.Comment: 13 pages 9 figures, talk given at Finite Density QCD at Nara, Nara,
Japan, 10-12 July 200
Gajenje karaša (Carassius carassius) u ribnjacima
Uzgoj juvenilnih jedinki karaša (C. carassius) analiziran je u pet ribnjačkih objekata veličine 100 m2. Karaš je gajen u monokulturi u dva, dok je sa linjakom gajen u bikulturi u tri ribnjačka jezera. Stopa preživljavanja karaša u monokulturi iznosila je 21.15±6.86 %, a u bikulturi 47.07±16.86%. Kod linjaka je zabeležena veca stopa preživljavanja (69.33±16.76) i brži rast u odnosu na karaša. Iako je prema dobijenim rezultatima teško proceniti razlike između uzgoja u monokulturi i bikulturi, može se zaključiti da linjak nije značajan kompetitor karašu
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