6,038 research outputs found
Non-singular inflation with vacuum decay
On the basis of a semi-classical analysis of vacuum energy in an expanding
spacetime, we describe a non-singular cosmological model in which the vacuum
density decays with time, with a concomitant production of matter. During an
infinitely long period we have an empty, inflationary universe, with H \approx
1. This primordial era ends in a fast phase transition, during which H and
\Lambda decrease to nearly zero in a few Planck times, with release of a huge
amount of radiation. The late-time scenario is similar to the standard model,
with the radiation phase followed by a long dust era, which tends
asymptotically to a de Sitter universe, with vacuum dominating again. An
analysis of the redshift-distance relation for supernovas Ia leads to
cosmological parameters in agreement with other current estimations.Comment: Work presented at IRGAC 2006, Barcelona, July 11-15 2006. To appear
in a special issue of Journal of Physics
Evidence of Two Distinct Dynamic Critical Exponents in Connection with Vortex Physics
The dynamic critical exponent is determined from numerical simulations
for the three-dimensional (3D) lattice Coulomb gas (LCG) and the 3D XY models
with relaxational dynamics. It is suggested that the dynamics is characterized
by two distinct dynamic critical indices and related to the
divergence of the relaxation time by and
, where is the correlation length and the
wavevector. The values determined are and for the
3D LCG and and for the 3D XY model. It is argued
that the nonlinear exponent relates to , whereas the usual
Hohenberg-Halperin classification relates to . Possible implications for the
interpretation of experiments are pointed out. Comparisons with other existing
results are discussed.Comment: to appear in PR
Sociodemographic profile and self-referred health conditions of the elderly in a city of Southern Brazil
OBJECTIVE: To assess the association between gender and age groups and socioeconomic and health variables among older adults. METHODS: Cross-sectional study carried out in the a city in Southern Brazil, in 2004. Elderly over 60 years of age (N= 292) were selected through two-stage probabilistic sampling. Data from socioeconomic and demographic variables were collected through household survey. Health conditions were self-referred. Descriptive statistics, and Pearson's Chi-square test with linear-by-linear association model were used for data analysis. RESULTS: Among the elderly, 67.8% were female, 84% were between 60 to 79 years and 81% considered themselves healthy. Compared to men, women were more likely to live alone (p=0.046), have no partner (p<0.001), be less educated (p=0.021), report more health conditions (p=0,003), use more medications (p=0.016), exercise less (p=0.015), be more dependent to perform activities of daily living (p<0.001), receive lower pension benefits (p<0,001), have less paid jobs (p=0.002). But women perceived themselves as having more social support (p=0.023), consumed less alcohol (p=0.003) and were not smokers (p<0.001). Those with more advanced age were less educated (p<0.001), had poorer economic conditions (p=0.004), received lower pension benefits (p<0,001), were less likely have a partner (p<0.001) and were more dependent to perform activities of daily living (p<0.001) but perceived themselves with more social support (p=0.014) and were not smokers (p<0.001). CONCLUSIONS: Differences between gender and age group were evidenced and they were more marked among women and those with more advanced age.OBJETIVO: Avaliar a associação entre sexo e grupo etário com variáveis socioeconômicas e de saúde dos idosos. MÉTODOS: Estudo transversal realizado no Distrito Noroeste de Porto Alegre, Rio Grande do Sul, em 2004. Foram estudados indivíduos acima de 60 anos (N=292), selecionados por amostra probabilística em dois estágios. Os dados de variáveis socioeconômicas e demográficas foram coletados por inquérito domiciliar. As condições de saúde foram auto-referidas. Foram realizadas análises descritivas, de qui-quadrado de Pearson e tendência linear. RESULTADOS: Entre os idosos, 67,8% eram do sexo feminino, 84% encontravam-se na faixa dos 60 aos 79 anos, 81% consideravam-se saudáveis. Em comparação com os homens, as mulheres moravam mais sozinhas (p=0,046), sem companheiro (p<0,001), tinham menor escolaridade (p=0,021); relatavam mais problemas de saúde (p=0,003) e uso de medicação sistemática (p=0,016); realizavam menos atividades físicas (p=0,015) e eram mais dependentes nas atividades de vida diária (p<0,001), recebiam menos aposentadoria (p<0,001), exerciam menos atividades remuneradas (p=0,002), mas se percebiam mais apoiadas pela rede social informal (p=0,023), consumiam menos bebidas alcoólicas (p=0,003) e não eram fumantes (p<0,001). Os mais idosos tinham menor escolaridade (p<0,001), piores condições econômicas (p=0,004), recebiam menos aposentadoria (p<0,001), não tinham companheiro (p<0,001), eram mais dependentes nas atividades de vida diária (p<0,001), mas se percebiam mais apoiados pela rede social informal (p=0,014) e não eram fumantes (p<0,001). CONCLUSÕES: Foram evidenciadas diferenças quanto a gênero e grupo etário para variáveis socioeconômicas e de saúde, sendo piores para as mulheres e para os idosos mais velhos.Universidade Federal de São Paulo (UNIFESP)UNIFESP Departamento de EnfermagemUNIFESP, Depto. de EnfermagemSciEL
Host status of fruit plants to meloidogyne enterolobii.
Edição dos Proceedings do 6th International Congress of Nematology, Cape Town, South Africa, May 2014
Symmetries and Ambiguities in the linear sigma model with light quarks
We investigate the role of undetermined finite contributions generated by
radiative corrections in a linear sigma model with quarks.
Although some of such terms can be absorbed in the renormalization procedure,
one such contribution is left in the expression for the pion decay constant.
This arbitrariness is eliminated by chiral symmetry.Comment: 9 pages. Added references through the text; an author was added due
to an important contribution; corrected typos; the title also was changed.
Submitted to Modern Physics Letter
Vortex-line liquid phases: Longitudinal superconductivity in the lattice London model
We study the vortex-line lattice and liquid phases of a clean type-II
superconductor by means of Monte Carlo simulations of the lattice London model.
Motivated by a recent controversy regarding the presence, within this model, of
a vortex-liquid regime with longitudinal superconducting coherence over long
length scales, we directly compare two different ways to calculate the
longitudinal coherence. For an isotropic superconductor, we interpret our
results in terms of a temperature regime within the liquid phase in which
longitudinal superconducting coherence extends over length scales larger than
the system thickness studied. We note that this regime disappears in the
moderately anisotropic case due to a proliferation, close to the flux-line
lattice melting temperature, of vortex loops between the layers.Comment: 8 pages, Revtex, with eps figures. To appear in Phys. Rev.
A SOA web-based group decision support system considering affective aspects
The topic of Group Decision Support Systems (GDSS) has been studied
over the last decades. Supporting decision-makers that participate in group
decision-making processes is a complex task, especially when decision-makers
have no opportunity to gather at the same place and at the same time. In this
work, we propose a Web based Group Decision Support System (WebGDSS)
which intends to support decision-makers anywhere, anytime and through almost
any kind of devices. Our system was developed under a SOA architecture and we
used a multi criteria algorithm that features decision-makers’ cognitive aspects,
as well as a component of generation of intelligent reports to feedback the results
of decision-making processes to the decision-makers.This work was supported by GECAD - Research Group on
Intelligent Engineering and Computing for Advanced Innovation and Development
and by National Funds through the FCT - Fundação para a Ciência e a
Tecnologia (Portuguese Foundation for Science and Technology) with the João
Carneiro Ph.D. Grant with the Reference SFRH/BD/89697/2012.info:eu-repo/semantics/publishedVersio
- …