312 research outputs found
RNAI-Mediated resistance to bean golden mosaic virus in genetically engineered common bean (Phaseolus vulgaris).
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Previous issue date: 2008-01-1
Real Time Analysis of Thermal Activation via Sphaleron Transitions
We study the process of thermal activation mediated by sphaleron transitions
by analyzing the real-time dynamics of the decay out of equilibrium in a
dimensional field theory with a metastable state. The situation considered is
that of a rapid supercooling in which the system is trapped in a metastable
state at a temperature larger than the mass of the quanta, but smaller than the
energy to create a critical droplet. The initial density matrix is evolved in
time and the nucleation rate (probability current at the saddle point) is
computed. The nucleation rate is {\it time dependent}, vanishing at early
times, reaching a maximum at a time with the mass of quanta
in the metastable state, and decreasing at long times as a consequence of
unitarity. An estimate for the average number of particles of ``true vacuum''
produced as a function of time during the nucleation process is obtained.Comment: 26 pages 6 figures (available upon request), PITT-93-06, LATE
Previsão da incidência da leishmaniose visceral usando o modelo de média móvel integrado autorregressivo sazonal (SARIMA) no Maranhão, Brasil
Universidade Federal do Maranhão. Programa de Pós‑graduação Strictu Sensu em Saúde e Ambiente. São Luís, MA, Brasil.Universidade Estadual do Maranhão - Campus Caxias. Programa de Pós‑graduação Strictu Sensu em Biodiversidade, Ambiente e Saúde. Caxias, MA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde e Ambiente. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Universidade Federal do Maranhão. Programa de Pós‑graduação Strictu Sensu em Saúde e Ambiente. São Luís, MA, Brasil.Universidade Estadual do Maranhão - Campus Caxias. Programa de Pós‑graduação Strictu Sensu em Biodiversidade, Ambiente e Saúde. Caxias, MA, Brasil.Universidade Estadual do Maranhão - Campus Caxias. Programa de Pós‑graduação Strictu Sensu em Biodiversidade, Ambiente e Saúde. Caxias, MA, Brasil.Universidade Estadual do Maranhão - Campus Caxias. Programa de Pós‑graduação Strictu Sensu em Biodiversidade, Ambiente e Saúde. Caxias, MA, Brasil.Universidade Federal do Maranhão. Programa de Pós‑graduação Strictu Sensu em Saúde e Ambiente. São Luís, MA, Brasil.Universidade Federal do Maranhão. Programa de Pós‑graduação Strictu Sensu em Saúde e Ambiente. São Luís, MA, Brasil.Visceral leishmaniasis (VL) is an infectious disease predominant in countries located in the tropics. The prediction of occurrence of infectious diseases through epidemiologic modeling has revealed to be an important tool in the understanding of its occurrence dynamic. The objective of this study was to develop a forecasting model for the incidence of VL in Maranhão using the Seasonal Autoregressive Integrated Moving Average model (SARIMA). We collected monthly data regarding VL cases from the National Disease Notification System (SINAN) corresponding to the period between 2001 and 2018. The Box‑Jenkins method was applied in order to adjust a SARIMA prediction model for VL general incidence and by sex (male or female) for the period between January 2019 and December 2013. For 216 months of this time series, 10,431 cases of VL were notified in Maranhão, with an average of 579 cases per year. With regard to age range, there was a higher incidence among the pediatric public (0 to 14 years of age). There was a predominance in male cases, 6437 (61.71%). The Box‑Pierce test figures for overall, male and female genders supported by the results of the Ljung‑Box test suggest that the autocorrelations of residual values act as white noise. Regarding monthly occurrences in general and by gender, the SARIMA models (2,0,0) (2,0,0), (0,1,1) (0,1,1) and (0,1,1) (2, 0, 0) were the ones that mostly adjusted to the data respectively. The model SARIMA has proven to be an adequate tool for predicting and analyzing the trends in VL incidence in Maranhão. The time variation determination and its prediction are decisive in providing guidance in health measure intervention
Multiflavor Correlation Functions in non-Abelian Gauge Theories at Finite Density in two dimensions
We compute vacuum expectation values of products of fermion bilinears for
two-dimensional Quantum Chromodynamics at finite flavored fermion densities. We
introduce the chemical potential as an external charge distribution within the
path-integral approach and carefully analyse the contribution of different
topological sectors to fermion correlators. We show the existence of chiral
condensates exhibiting an oscillatory inhomogeneous behavior as a function of a
chemical potential matrix. This result is exact and goes in the same direction
as the behavior found in QCD_4 within the large N approximation.Comment: 28 pages Latex (3 pages added and other minor changes) to appear in
Phys.Rev.
Minimal knotted polygons in cubic lattices
An implementation of BFACF-style algorithms on knotted polygons in the simple
cubic, face centered cubic and body centered cubic lattice is used to estimate
the statistics and writhe of minimal length knotted polygons in each of the
lattices. Data are collected and analysed on minimal length knotted polygons,
their entropy, and their lattice curvature and writhe
A Factorization Law for Entanglement Decay
We present a simple and general factorization law for quantum systems shared
by two parties, which describes the time evolution of entanglement upon passage
of either component through an arbitrary noisy channel. The robustness of
entanglement-based quantum information processing protocols is thus easily and
fully characterized by a single quantity.Comment: 4 pages, 5 figure
Crossover phenomena in spin models with medium-range interactions and self-avoiding walks with medium-range jumps
We study crossover phenomena in a model of self-avoiding walks with
medium-range jumps, that corresponds to the limit of an -vector
spin system with medium-range interactions. In particular, we consider the
critical crossover limit that interpolates between the Gaussian and the
Wilson-Fisher fixed point. The corresponding crossover functions are computed
using field-theoretical methods and an appropriate mean-field expansion. The
critical crossover limit is accurately studied by numerical Monte Carlo
simulations, which are much more efficient for walk models than for spin
systems. Monte Carlo data are compared with the field-theoretical predictions
concerning the critical crossover functions, finding a good agreement. We also
verify the predictions for the scaling behavior of the leading nonuniversal
corrections. We determine phenomenological parametrizations that are exact in
the critical crossover limit, have the correct scaling behavior for the leading
correction, and describe the nonuniversal lscrossover behavior of our data for
any finite range.Comment: 43 pages, revte
Critical Exponents, Hyperscaling and Universal Amplitude Ratios for Two- and Three-Dimensional Self-Avoiding Walks
We make a high-precision Monte Carlo study of two- and three-dimensional
self-avoiding walks (SAWs) of length up to 80000 steps, using the pivot
algorithm and the Karp-Luby algorithm. We study the critical exponents
and as well as several universal amplitude ratios; in
particular, we make an extremely sensitive test of the hyperscaling relation
. In two dimensions, we confirm the predicted
exponent and the hyperscaling relation; we estimate the universal
ratios , and (68\% confidence
limits). In three dimensions, we estimate with a
correction-to-scaling exponent (subjective 68\%
confidence limits). This value for agrees excellently with the
field-theoretic renormalization-group prediction, but there is some discrepancy
for . Earlier Monte Carlo estimates of , which were , are now seen to be biased by corrections to scaling. We estimate the
universal ratios and ; since , hyperscaling holds. The approach to
is from above, contrary to the prediction of the two-parameter
renormalization-group theory. We critically reexamine this theory, and explain
where the error lies.Comment: 87 pages including 12 figures, 1029558 bytes Postscript
(NYU-TH-94/09/01
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