2,192 research outputs found
On finite--temperature and --density radiative corrections to the neutrino effective potential in the early Universe
Finite-temperature and -density radiative corrections to the neutrino
effective potential in the otherwise CP-symmetric early Universe are considered
in the real-time approach of Thermal Field Theory. A consistent perturbation
theory endowed with the hard thermal loop resummation techniques developed by
Braaten and Pisarski is applied. Special attention is focused on the question
whether such corrections can generate any nonzero contribution to the
CP-symmetric part of the neutrino potential, if the contact approximation for
the W-propagator is used.Comment: 11 pages, revtex styl
Extraction and Identification of Clavine and Lysergic Acid Alkaloids from Morning Glories
Author Institution: Department of Zoology and Microbiology, Ohio UniversityWITTERS, WELDON L. Extraction and identification of clavine and lysergic acid alkaloids from morning glories. Ohio J. Sci. 75(4): 198, 1975
Predicting Optimal Targeting Strategies in Multispecies Fisheries: A Portfolio Approach
When regulations are species specific but the species are part of a multispecies fishery, studies show that harvest rates are correlated such that net revenues attributed to each species are also correlated. This correlation suggests that portfolio theory is well suited for multispecies fisheries that exhibit joint productive characteristics. This paper uses a portfolio approach to model the behavior of fishermen faced with multiple targeting options in a random harvest fishery. The approach draws from the expected utility hypothesis and financial portfolio theory to predict optimal targeting strategies. The methodology is applied to the pelagic longline fleet operating in the U.S. Atlantic Ocean, Caribbean, and Gulf of Mexico. The model provides evidence that area closures aimed at reducing juvenile swordfish mortality will be more effective in certain regions. Efficient risk-return frontiers are also generated for use in predicting targeting behavior in lieu of a closure.fisheries economics, fisheries management, highly migratory species, multispecies fisheries, portfolio theory, swordfish, targeting strategies, Resource /Energy Economics and Policy, Q22, G11, D81, C61,
Practices Used by Dairy Farmers to Reduce Seasonal Production Variability
The objective of this analysis was to identify the production practices used by farmers to change seasonal production. Production practices included milk production per cow, proportion of cows milking, number of first lactation animals entering the herd, number of cows leaving the herd, number of days to first breeding, and calves born. Farms that participated in a seasonal pricing plan during 1993, 1994, and 1995 decreased production practice seasonality in response to price premiums, which caused a decrease in production seasonality compared to nonparticipating farms. Participating farms showed a preference for adjusting entering first lactation animals and number of calves born, but did make adjustments in other practices as well.Livestock Production/Industries,
Behavior of logarithmic branch cuts in the self-energy of gluons at finite temperature
We give a simple argument for the cancellation of the log(-k^2) terms (k is
the gluon momentum) between the zero-temperature and the temperature-dependent
parts of the thermal self-energy.Comment: 4 page
On the Role of Chaos in the AdS/CFT Connection
The question of how infalling matter in a pure state forms a Schwarzschild
black hole that appears to be at non-zero temperature is discussed in the
context of the AdS/CFT connection. It is argued that the phenomenon of
self-thermalization in non-linear (chaotic) systems can be invoked to explain
how the boundary theory, initially at zero temperature self thermalizes and
acquires a finite temperature. Yang-Mills theory is known to be chaotic
(classically) and the imaginary part of the gluon self-energy (damping rate of
the gluon plasma) is expected to give the Lyapunov exponent. We explain how the
imaginary part would arise in the corresponding supergravity calculation due to
absorption at the horizon of the black hole.Comment: 18 pages. Latex file. Minor changes. Final version to appear in
Modern Physics Letters
Gauge Independence of Limiting Cases of One-Loop Electron Dispersion Relation in High-Temperature QED
Assuming high temperature and taking subleading temperature dependence into
account, gauge dependence of one-loop electron dispersion relation is
investigated in massless QED at zero chemical potential. The analysis is
carried out using a general linear covariant gauge. The equation governing the
gauge dependence of the dispersion relation is obtained and used to prove that
the dispersion relation is gauge independent in the limiting case of momenta
much larger than . It is also shown that the effective mass is not
influenced by the leading temperature dependence of the gauge dependent part of
the effective self-energy. As a result the effective mass, which is of order
, does not receive a correction of order from one loop, independent
of the gauge parameter.Comment: Revised and enlarged version, 14 pages, Revte
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