61,534 research outputs found
Two-point Taylor Expansions of Analytic Functions
Taylor expansions of analytic functions are considered with respect to two
points. Cauchy-type formulas are given for coefficients and remainders in the
expansions, and the regions of convergence are indicated. It is explained how
these expansions can be used in deriving uniform asymptotic expansions of
integrals. The method is also used for obtaining Laurent expansions in two
points.Comment: 14 pages, 10 figure
Fishes of the Lagunas Encadenadas (Province of Buenos Aires, Argentina), a wetland of international importance
The Lagunas Encadenadas form a large endorheic wetland. The system comprises a chain of five main lagoons (Alsina, Chochico, Del Monte, Del Venado, and Epecuen). During two recent collection trips, 13 species of fish were caught. From the collected material and available data in the literature the following points can be made: The fish fauna of this wetland comprises 18 species from 11 families and six orders. Four species (Cyprinus carpio, Hoplias malabaricus, Loricariichthys anus and Parapimelodus valenciennis) are new records for these water bodies. Fish species diversity decreases from east to west, ie from the most freshwater lagoon (Alsina, with 15 species) to the most saline (Epecuen, 1 species). A similar diversity pattern has been found in zooplankton species
New Precision Electroweak Tests of SU(5) x U(1) Supergravity
We explore the one-loop electroweak radiative corrections in supergravity via explicit calculation of vacuum-polarization and
vertex-correction contributions to the and
parameters. Experimentally, these parameters are obtained from a global fit to
the set of observables , and . We
include -dependent effects, which induce a large systematic negative shift
on for light chargino masses (m_{\chi^\pm_1}\lsim70\GeV). The
(non-oblique) supersymmetric vertex corrections to \Zbb, which define the
parameter, show a significant positive shift for light chargino
masses, which for can be nearly compensated by a negative
shift from the charged Higgs contribution. We conclude that at the 90\%CL, for
m_t\lsim160\GeV the present experimental values of and
do not constrain in any way supergravity in
both no-scale and dilaton scenarios. On the other hand, for m_t\gsim160\GeV
the constraints on the parameter space become increasingly stricter. We
demonstrate this trend with a study of the m_t=170\GeV case, where only a
small region of parameter space, with \tan\beta\gsim4, remains allowed and
corresponds to light chargino masses (m_{\chi^\pm_1}\lsim70\GeV). Thus
supergravity combined with high-precision LEP data would
suggest the presence of light charginos if the top quark is not detected at the
Tevatron.Comment: LaTeX, 11 Pages+4 Figures(not included), the figures available upon
request as an uuencoded file(0.4MB) or 4 PS files from [email protected],
CERN-TH.7078/93, CTP-TAMU-68/93, ACT-24/9
Radion Assisted Gauge Inflation
We propose an extension to the recently proposed extranatural or gauge
inflation scenario in which the radius modulus field around which the Wilson
loop is wrapped assists inflation as it shrinks. We discuss how this might lead
to more generic initial conditions for inflation.Comment: 10 pages, 2 figure
Nagel scaling and relaxation in the kinetic Ising model on a n-isotopic chain
The kinetic Ising model on a n-isotopic chain is considered in the framework
of Glauber dynamics. The chain is composed of N segments with n sites, each one
occupied by a different isotope. Due to the isotopic mass difference, the n
spins in each segment have different relaxation times in the absence of the
interactions, and consequently the dynamics of the system is governed by
multiple relaxation mechanisms. The solution is obtained in closed form for
arbitrary n, by reducing the problem to a set of n coupled equations, and it is
shown rigorously that the critical exponent z is equal to 2. Explicit results
are obtained numerically for any temperature and it is also shown that the
dynamic susceptibility satisfies the new scaling (Nagel scaling) proposed for
glass-forming liquids. This is in agreement with our recent results (L. L.
Goncalves, M. Lopez de Haro, J. Taguena-Martinez and R. B. Stinchcombe, Phys.
Rev. Lett. 84, 1507 (2000)), which relate this new scaling function to multiple
relaxation processes.Comment: 4 pages, 2 figures, presented at Ising Centennial Colloquium, to be
published in the Proceedings (Brazilian Journal of Physics.
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