57 research outputs found
Thermodynamic Properties of the 2N-Piece Relativistic String
The thermodynamic free energy F(\beta) is calculated for a gas consisting of
the transverse oscillations of a piecewise uniform bosonic string. The string
consists of 2N parts of equal length, of alternating type I and type II
material, and is relativistic in the sense that the velocity of sound
everywhere equals the velocity of light. The present paper is a continuation of
two earlier papers, one dealing with the Casimir energy of a 2N--piece string
[I. Brevik and R. Sollie (1997)], and another dealing with the thermodynamic
properties of a string divided into two (unequal) parts [I. Brevik, A. A.
Bytsenko and H. B. Nielsen (1998)]. Making use of the Meinardus theorem we
calculate the asymptotics of the level state density, and show that the
critical temperatures in the individual parts are equal, for arbitrary
spacetime dimension D. If D=26, we find \beta= (2/N)\sqrt{2\pi /T_{II}}, T_{II}
being the tension in part II. Thermodynamic interactions of parts related to
high genus g is also considered.Comment: 15 pages, LaTeX, 2 figures. Discussion in section 8 expande
Mellin-Barnes Representation for the Genus-g Finite Temperature String Theory
The Mellin-Barnes representation for the free energy of the genus- string
is constructed. It is shown that the interactions of the open bosonic string do
not modify the critical (Hagedorn) temperature. However,for the sectors having
a spinor structure, the critical temperature exists also for all and
depends on the windings. The appearance of a periodic structure is briefly
discussed.Comment: 9 pages, report UTF 294 (1993
Quantum Fields and Extended Objects in Space-Times with Constant Curvature Spatial Section
The heat-kernel expansion and -regularization techniques for quantum
field theory and extended objects on curved space-times are reviewed. In
particular, ultrastatic space-times with spatial section consisting in manifold
with constant curvature are discussed in detail. Several mathematical results,
relevant to physical applications are presented, including exact solutions of
the heat-kernel equation, a simple exposition of hyperbolic geometry and an
elementary derivation of the Selberg trace formula. With regards to the
physical applications, the vacuum energy for scalar fields, the one-loop
renormalization of a self-interacting scalar field theory on a hyperbolic
space-time, with a discussion on the topological symmetry breaking, the finite
temperature effects and the Bose-Einstein condensation, are considered. Some
attempts to generalize the results to extended objects are also presented,
including some remarks on path integral quantization, asymptotic properties of
extended objects and a novel representation for the one-loop (super)string free
energy.Comment: Latex file, 122 page
Effect of resveratrol on alcohol-induced mortality and liver lesions in mice
BACKGROUND: Resveratrol is a polyphenol with important antiinflammatory and antioxidant properties. We investigated the effect of resveratrol on alcohol-induced mortality and liver lesions in mice. METHODS: Mice were randomly distributed into four groups (control, resveratrol-treated control, alcohol and resveratrol-treated alcohol). Chronic alcohol intoxication was induced by progressively administering alcohol in drinking water up to 40% v/v. The mice administered resveratrol received 10 mg/ml in drinking water. The animals had free access to standard diet. Blood levels were determined for transaminases, IL-1 and TNF-α. A histological evaluation was made of liver damage, and survival among the animals was recorded. RESULTS: Transaminase concentration was significantly higher in the alcohol group than in the rest of the groups (p < 0.05). IL-1 levels were significantly reduced in the alcohol plus resveratrol group compared with the alcohol group (p < 0.05). TNF-α was not detected in any group. Histologically, the liver lesions were more severe in the alcohol group, though no significant differences between groups were observed. Mortality in the alcohol group was 78% in the seventh week, versus 22% in the alcohol plus resveratrol group (p < 0.001). All mice in the alcohol group died before the ninth week. CONCLUSION: The results obtained suggest that resveratrol reduces mortality and liver damage in mice
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