Variation of the first Hilbert coefficients of parameters with a common integral closure

A problem posed by Wolmer V. Vasconcelos on the variation of the first Hilbert coefficients of parameter ideals with a common integral closure in a local ring is studied. Affirmative answers are given and counterexamples are explored as well

Invasion Percolation Between two Sites

We investigate the process of invasion percolation between two sites (injection and extraction sites) separated by a distance r in two-dimensional lattices of size L. Our results for the non-trapping invasion percolation model indicate that the statistics of the mass of invaded clusters is significantly dependent on the local occupation probability (pressure) Pe at the extraction site. For Pe=0, we show that the mass distribution of invaded clusters P(M) follows a power-law P(M) ~ M^{-\alpha} for intermediate values of the mass M, with an exponent \alpha=1.39. When the local pressure is set to Pe=Pc, where Pc corresponds to the site percolation threshold of the lattice topology, the distribution P(M) still displays a scaling region, but with an exponent \alpha=1.02. This last behavior is consistent with previous results for the cluster statistics in standard percolation. In spite of these discrepancies, the results of our simulations indicate that the fractal dimension of the invaded cluster does not depends significantly on the local pressure Pe and it is consistent with the fractal dimension values reported for standard invasion percolation. Finally, we perform extensive numerical simulations to determine the effect of the lattice borders on the statistics of the invaded clusters and also to characterize the self-organized critical behavior of the invasion percolation process.Comment: 7 pages, 11 figures, submited for PR

Biomass equations for forest regrowth in the eastern Amazon using randomized branch sampling.

Florestas secundárias ocupam uma área extensa e crescente na bacia Amazônica, porém determinações acuradas do impacto dessas florestas nos ciclos de carbono e nutrientes têm sido dificultadas pelo número reduzido de equações alométricas. Neste estudo, nós desenvolvemos equações em nível de comunidade e espécies individuais para estimar a biomassa total da parte aérea de uma floresta secundária com 15 anos de idade na Amazônia oriental. O trabalho de campo utilizou amostragem aleatória de ramos, que é uma técnica rápida, porém pouco utilizada em florestas tropicais. Baseada no erro padrão da série de segmentos individuais (14%), a consistência da série de segmentos totais amostrados foi considerada elevada, sugerindo que o método pode ser eficiente em comparação com procedimentos tradicionais. Os melhores ajustes foram obtidos com a equação tradicional Y=a×DBHb, onde Y é a biomassa, DBH é o diâmetro à altura do peito, e a e b são parâmetros para cada espécie arbórea. Ajustes razoáveis também foram alcançados com equações da forma Y=a(BA×H), onde Y é a biomassa, BA é a área basal, H é a altura e a é um parâmetro específico para cada espécie arbórea. Comparações com equações disponíveis na literatura indicaram uma faixa de erro provável de -33% a +29% usando-se relações desenvolvidas para outros sítios. Nós também apresentamos equações para os seguintes componentes da biomassa da parte aérea: tronco, ramos e folhas

LINFOPENIA T CD4 NO LUPUS ERITEMATOSO SISTÉMICO

Abstract: Background: Systemic Lupus Erythematosus (SLE) is an inflammatory chronic disease characterized by the presence of autoantibodies, immunocomplex production and organ injury. Several alterations of the immune system have been described, namely of CD4 T cells, with particular focus on regulatory subgroup. Objective: Quantify peripheral CD4 T cells in a population of patients with SLE and correlate it with lupus activity, affected organs, therapeutics and infections. Methods: Retrospective study involving all SLE patients seen in the clinical immunology outpatient clinic of the Hospital Geral Santo António, Porto that has done some peripheral blood flow cytometry study. Results: Twenty-nine patients have been evaluated, 16 were taking glucocorticoids and six immunossupressors. The mean SLEDAI at the study time was nine and the ECLAM was three. Thirty-one percent of the patients had leukopenia, 76% lymphocytopenia and the same number CD4 depletion. Fifty-five percent of the patients had CD4 levels lower than 500/mm3, 31% lower than 200/mm3. All patients with SLEDAI ?20 and ECLAM ?4 had CD4 counts inferior to 500/mm3 and all patients with inactive disease had CD4 superior to 500/mm3. There have been three opportunistic infections: cryptococcal meningitis, pulmonary aspergilosis, Pneumocystis jirovecii pneumonia, all in patients with CD4 counts lower than 500/mm3. Conclusion: Decreased CD4 T cells counts have been very common in this study population. There is an inverse relation between CD4 cells counts and disease activity. Opportunistic infections occurred in patients with severe CD4 depletion. Keywords: Systemic Lupus Erythematosus; CD4 T Lymphocytes; Lymphocytopenia; SLE Activity; Opportunistic infection

LINFOPENIA T CD4 NO LUPUS ERITEMATOSO SISTÉMICO

Abstract: Background: Systemic Lupus Erythematosus (SLE) is an inflammatory chronic disease characterized by the presence of autoantibodies, immunocomplex production and organ injury. Several alterations of the immune system have been described, namely of CD4 T cells, with particular focus on regulatory subgroup. Objective: Quantify peripheral CD4 T cells in a population of patients with SLE and correlate it with lupus activity, affected organs, therapeutics and infections. Methods: Retrospective study involving all SLE patients seen in the clinical immunology outpatient clinic of the Hospital Geral Santo António, Porto that has done some peripheral blood flow cytometry study. Results: Twenty-nine patients have been evaluated, 16 were taking glucocorticoids and six immunossupressors. The mean SLEDAI at the study time was nine and the ECLAM was three. Thirty-one percent of the patients had leukopenia, 76% lymphocytopenia and the same number CD4 depletion. Fifty-five percent of the patients had CD4 levels lower than 500/mm3, 31% lower than 200/mm3. All patients with SLEDAI ?20 and ECLAM ?4 had CD4 counts inferior to 500/mm3 and all patients with inactive disease had CD4 superior to 500/mm3. There have been three opportunistic infections: cryptococcal meningitis, pulmonary aspergilosis, Pneumocystis jirovecii pneumonia, all in patients with CD4 counts lower than 500/mm3. Conclusion: Decreased CD4 T cells counts have been very common in this study population. There is an inverse relation between CD4 cells counts and disease activity. Opportunistic infections occurred in patients with severe CD4 depletion. Keywords: Systemic Lupus Erythematosus; CD4 T Lymphocytes; Lymphocytopenia; SLE Activity; Opportunistic infection

The influence of physical activity in the positive mental health of the elder

This study aim to investigate the physical activity levels of older adults and its effect on life satisfaction, self-esteem and personal growth. A sample of 168 elderly persons of both sexes with ages between 60 and 95 years (M= 72.06, SD= 6.83) was used. Results reveal that about 41.1% of the sample is physically inactive, while only 31.5% of the older adults reported physical activity levels equal or above international recommended amounts. Correlation and comparative analysis demonstrate that physical activity participation is associated with higher levels of life satisfaction, self-esteem and personal growth, and that this effect is superior in the elderly people who practice at least 30 minutes of moderate-intensity aerobic physical activity on five or more days a week