A família de distribuições univariadas gama-generalizada proposta por Zografos e Balakrishnan [3] foi discutida por Nadarajah et al. [7] que deram um amplo tratamento matemático a esta classe. Neste artigo, estudamos o modelo Gama Weibull Poisson, que tem como casos especiais, várias distribuições discutidas na literatura. Deduzimos uma expressão explícita para a entropia de Rényi, e mostramos que a densidade da distribuição Gama Weibull Poisson é uma mistura de densidades da distribuição Weibull Poisson. Estudamos algumas propriedades matemáticas importantes como momentos, função geratriz de momentos e função quantílica.

In this paper, we study the gamma Weibull Poisson distribution that has many special cases of distributions discussed in the literature. We study some important mathematical properties such as moments, moment generating and quantile functions. We obtain an explicit expression for Rényi entropy. Further, we write the probability density function of the GWP distribution as a linear combination of WP density functions.

The purpose of this work was to investigate the influence of the hot pressing variables, namely pressure, time and temperature, on the microstructure, density and hardness in a sterling silver alloy. Powders were hot pressed under different combinations of pressures (25MPa, 35MPa and 45MPa), times (10 min, 30 min and 60 min) and temperatures (250 ºC, 300 ºC, 400 ºC, 500 ºC and 700 ºC). The microstructures of hot pressed compacts were analyzed by the means of SEM/EDS and optical microscopy. The density and hardness of specimens were assessed. The microstructure of all specimens consisted in Cu-rich precipitates of different sizes dispersed in a Ag-rich matrix. Of the variables that were examined, only temperature produced significant (p<0.05) differences in the density and hardness of the compacts. Full density of powders compacts was achieved for temperatures above 400 ºC, irrespective of the hot pressing time. A hardness peak (~120HV) was observed for the specimens hot pressed at 400 ºC.

No Brasil existem poucos estudos sobre a ocorrência da infecção pelo vírus da imunodeficiência felina (FIV), assim como a determinação dos subtipos circulantes, o que é indispensável para o desenvolvimento de vacinas e novos testes diagnósticos. O presente trabalho investigou a ocorrência da infecção pelo FIV entre os anos de 2010 e 2011 em gatos domésticos submetidos a atendimento clínico na cidade de Pelotas e região. Amostras de sangue total de 70 animais, incluindo suspeitos (28) ou não suspeitos (42) da infecção pelo FIV, foram submetidas à reação de PCR nested. Os resultados indicaram uma frequência de infecção de 15,7% (11/70) e a análise dos fatores associados (sexo, idade e condição clínica) evidenciou uma maior ocorrência em gatos com idade superior a 10 anos e acometidos por infecções crônicas e recidivantes. Oito amostras positivas na PCR nested foram submetidas a sequenciamento genômico e somente o subtipo B foi detectado na região estudada.

In Brazil there are few studies on the occurrence of the feline immunodeficiency virus (FIV) infection and its subtypes, which are essential for the development of vaccines and new diagnostic tests. The present study investigated the occurrence of the FIV infection between 2010 and 2011 in domestic cats submitted to medical attendance in the city of Pelotas and nearby area. Total blood samples of seventy cats, suspected (28) or not (42) of infection by FIV were analyzed by nested PCR in order to perform a diagnosis. The results pointed to a FIV infection frequency of 15.7% (11/70) and the analysis of the risk factors related to infection (sex, age and clinical condition) evidenced a greater occurrence in cats up to 10 years of age with chronic and recurrent infections. Eight samples found positive by nested PCR were submitted to DNA sequencing indicating that only the subtype B was detected in the studied region.

O objetivo desse estudo foi realizar um ensaio toxicológico pré-clínico para analisar a toxicidade do chá das folhas de Morus nigra L. (Moraceae). A toxicidade subcrônica do chá (CF-Mn) foi avaliada durante 30 dias por via oral em ratos. Ao grupo controle foi administrado água, para comparação. Durante o período experimental foi avaliada a presença de sinais de toxicidade, variação do peso corporal, e o consumo de líquido e alimento. Ao final do experimento o sangue dos animais foi retirado para análise de parâmetros hematológicos e bioquímicos. Não foram observados mortalidade e sinais de toxicidade indicando baixa toxicidade da planta. Não houve alterações nos parâmetros hematológicos e bioquímicos. Nas condições do estudo, o CF-Mn pode ser considerado de baixa toxicidade, pois não produziu efeitos tóxicos nos animais tratados.

The aim of this study was to carry out a pre-clinical toxicological assay to analyze the toxicity of tea from the leaves of Morus nigra L. (Moraceae). The subchronic toxicity of this tea (CF-Mn) was orally evaluated during 30 days in rats. The control group was given water for comparison. During the experimental period, signs of toxicity, body weight variation, and water and food consumption were assessed. At the end of the experiment, the blood of animals was removed for analysis of hematological and biochemical parameters. No mortality and no toxicity signs were observed, indicating low toxicity of the plant. There was no alteration in the hematological and biochemical parameters. Under the study conditions, CF-Mn can be considered of low toxicity since it did not produce toxic effects in treated animals.

The reduction of hepatic microsomal transfer protein (MTP) activity results in fatty liver, worsening hepatic steatosis and fibrosis in chronic hepatitis C (CHC). The G allele of the MTP gene promoter, -493G/T, has been associated with lower transcriptional activity than the T allele. We investigated this association with metabolic and histological variables in patients with CHC. A total of 174 untreated patients with CHC were genotyped for MTP -493G/T by direct sequencing using PCR. All patients were negative for markers of Wilson’s disease, hemochromatosis and autoimmune diseases and had current and past daily alcohol intake lower than 100 g/week. The sample distribution was in Hardy-Weinberg equilibrium. Among subjects with genotype 1, 56.8% of the patients with fibrosis grade 3+4 presented at least one G allele versus 34.3% of the patients with fibrosis grade 1+2 (OR = 1.8; 95%CI = 1.3-2.3). Logistic regression analysis with steatosis as the dependent variable identified genotypes GG+GT as independent protective factors against steatosis (OR = 0.4, 95%CI = 0.2-0.8; P = 0.01). The results suggest that the presence of the G allele of MTP -493G/T associated with lower hepatic MTP expression protects against steatosis in our CHC patients.

Este artigo descreve a validação de método analítico para determinação do acaricida amitraz em mel utilizando extração com n-hexano/acetona, cleanup em cartucho de extração em fase sólida (SPE) e análise por cromatografia a gás com detector termoiônico seletivo (GC-TSD). O método pode ser utilizado para monitorar a presença do pesticida amitraz em mel, devido aos bons parâmetros analíticos, precisão (CV<11%) e exatidão (>80%) dentro do intervalo 100-400 ng g-1. O limite estabelecido na União Européia, pelo Committee for Veterinary Medicinal Products, para amitraz em mel (200 ng g-1) está dentro deste intervalo. A resposta do sistema analítico apresentou linearidade entre 100 e 800 ng mL-1 com coeficiente de correlação de 0,9996, limite de detecção (LD-7 ng g-1) e de quantificação (LQ-100 ng g-1). O método validado foi utilizado para avaliar a qualidade de méis comercializados na cidade de Araraquara/SP, nas quais não foram detectados resíduos de amitraz.

This paper describes the validation of method for analysis of the acaricide amitraz in honey using n-hexane/acetone extraction, cleanup in cartridge of solid phase extraction (SPE) and analysis by gas chromatography with nitrogen-phosphorus detector (GC -TSD). The method can be used to monitor the presence of the pesticide amitraz in honey because of its good analytical parameters, precision (CV <11%) and accuracy (> 80%) in the range of 100-400 ng g-1. The limit set in the European Union, by Committee for Veterinary Medicinal Products, for amitraz in honey (200 ng g-1) is within this range. The response of the analytical system was linear between 100 and 800 ng mL-1 with correlation coefficient of 0.9996, limit of detection (LD -7 ng g-1) and quantification (LQ -100 ng g-1). The sample was fortified at three concentrations 100 ng g-1, 200 ng g-1 and 400 ng g-1, giving an average recovery of 80, 88 and 92% respectively. The validated method was used to assess the quality of honey sold in the city of Araraquara/SP, in which there were no residues of amitraz.

O principal objectivo deste trabalho é o estudo do comportamento da fadiga com ‘fretting’ da liga de Ti6Al4V em contacto com uma liga de aço 34CrNiMo6, utilizando a configuração esfera - plano. Há um número significativo de parâmetros que podem afectar a vida de fadiga com ‘fretting’. A amplitude de deslocamento relativo e a carga normal do contacto são considerados parâmetros mais relevantes. Quando a liga de Ti6Al4V é submetida a fadiga com ‘fretting’ a vida da fadiga reduz drasticamente em comparação com o caso de fadiga tradicional. O objectivo deste estudo foi observar o efeito negativo do ‘fretting’ na vida de fadiga e para isso foram realizados testes tradicionais de fadiga e testes de fadiga com ‘fretting’. Há que realçar os efeitos sinergéticos entre a fadiga e o ‘fretting’. Além do trabalho experimental foi realizada uma análise não linear com Abaqus para determinar a influencia da carga normal no comportamento da fadiga com ‘fretting’. Foi verificada a forte dependência da vida de fadiga com ‘fretting’ com as duas variáveis estudadas, nomeadamente a amplitude de deslocamento relativo e a carga normal de contacto.

The main objective of this work is to study the fretting fatigue behaviour of Ti6Al4V in contact with a dissimilar mating material 34CrNiMo6 steel, using a sphere-on-plane configuration. There are a significant number of parameters that may affect fretting fatigue. Relative displacement amplitude and normal contact load are usually considered the most relevant ones. Thus, the role of relative displacement amplitude and normal load on fretting fatigue, life is presented. When the Ti6Al4V alloy is subjected to fretting fatigue the fatigue life drastically reduces as compared to the traditional plain fatigue case. In order to study this detrimental effect of fatigue life tests of both plain fatigue and fretting fatigue were carried out, highlighting the synergic effect between fatigue and fretting. Three different normal loads were used in the experiments. The relative displacement amplitude was changed by varying the tangential load. The fretting fatigue experiments were carried out in a fretting fatigue apparatus assembled on a servo hydraulic fatigue testing machine. In addition to the experimental work a nonlinear analysis using ABAQUS was carried out to determine the influence of the normal load on fretting fatigue behaviour. It was verified the strong dependence of fretting fatigue life on the two studied variables, namely the relative displacement amplitude and the normal contact load.