The complementary exponential power lifetime model

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

The Conway-Maxwell-Poisson-generalized gamma regression model with long-term survivors

In this paper, we proposed a flexible cure rate survival model by assuming the number of competing causes of the event of interest following the Conway-Maxwell distribution and the time for the event to follow the generalized gamma distribution. This distribution can be used to model survival data when the hazard rate function is increasing, decreasing, bathtub and unimodal-shaped including some distributions commonly used in lifetime analysis as particular cases. Some appropriate matrices are derived in order to evaluate local influence on the estimates of the parameters by considering different perturbations, and some global influence measurements are also investigated. Finally, data set from the medical area is analysed.

Sistema especialista para a monitoração do processo de degradação de medidores tipo indução de energia elétrica ativa

This paper presents a methodology and software for hazard rate analysis of induction type watt-hour meters, considering the main variables related with the degradation process of these meters, for the Elektro Electricity and Services SA. The modeling developed to calculate the watt-hour meters hazard rate was implemented in a tool through a user friendly platform, in Delphi language, enabling not only hazard rate analysis, but also a classification by risk range, localization of installation for the analyzed meters, and, allowing, through an expert system, the sampling of induction type watt-hour meters, based on the model risk developed with artificial intelligence, with the mainly goal of follow and manage the process of degradation, maintenance and replacement of these meters. © 2010 IEEE.

The Poisson-exponential lifetime distribution

In this paper we proposed a new two-parameters lifetime distribution with increasing failure rate. The new distribution arises on a latent complementary risk problem base. The properties of the proposed distribution are discussed, including a formal proof of its probability density function and explicit algebraic formulae for its reliability and failure rate functions, quantiles and moments, including the mean and variance. A simple EM-type algorithm for iteratively computing maximum likelihood estimates is presented. The Fisher information matrix is derived analytically in order to obtaining the asymptotic covariance matrix. The methodology is illustrated on a real data set. © 2010 Elsevier B.V. All rights reserved.

Specialist tool for monitoring the measurement degradation process of induction active energy meters

This paper presents a methodology and a specialist tool for failure probability analysis of induction type watt-hour meters, considering the main variables related to their measurement degradation processes. The database of the metering park of a distribution company, named Elektro Electricity and Services Co., was used for determining the most relevant variables and to feed the data in the software. The modeling developed to calculate the watt-hour meters probability of failure was implemented in a tool through a user friendly platform, written in Delphi language. Among the main features of this tool are: analysis of probability of failure by risk range; geographical localization of the meters in the metering park, and automatic sampling of induction type watt-hour meters, based on a risk classification expert system, in order to obtain information to aid the management of these meters. The main goals of the specialist tool are following and managing the measurement degradation, maintenance and replacement processes for induction watt-hour meters. © 2011 IEEE.

Modelação e análise da vida útil (metrológica) de medidores tipo indução de energia elétrica ativa

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Chronic fluoxetine treatment alters cardiovascular functions in unanesthetized rats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Parameter-dependent Lyapunov functions for state-derivative feedback control in polytopic linear systems

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Nitric oxide and L-type calcium channel influences the changes in arterial blood pressure and heart rate induced by central angiotesin II

We study the voltage dependent calcium channels and nitric oxide involvement in angiotensin II-induced pressor effect. The antipressor action of L-Type calcium channel antagonist, nifedipine, has been studied when it was injected into the third ventricle prior to angiotensin II. The influence of nitric oxide on nifedipine antipressor action has also been studied by utilizing N(W)-nitro-L-arginine methyl ester (LNAME) (40 mu g/0.2 mu l) a nitric oxide synthase inhibitor and L-arginine ( 20 mu g/0.2 mu l), a nitric oxide donor agent. Adult male Holtzman rats weighting 200-250 g, with cannulae implanted into the third ventricle were injected with angiotensin II. Angiotensin II produced an elevation in mean arterial pressure and a decreased in heart rate. Such effects were potentiated by the prior injection of LNAME. L-arginine and nifedipine blocked the effects of angiotensin II. These data showed the involvement of L-Type calcium channel and a free radical gas nitric oxide in the central control of angiotensin II-induced pressor effect. This suggested that L-Type calcium channel of the circunventricular structures of central nervous system participated in both short and long term neuronal actions of ANG II with the influence of nitrergic system.

The Poisson-exponential distribution: a Bayesian approach

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Hypochlorous acid inhibition by acetoacetate: Implications on neutrophil functions

Type-1 diabetic patients experience hyperketonemia caused by an increase in fatty acid metabolism. Thus, the aim of this study was to measure the effect of ketone bodies as suppressors of oxidizing species produced by stimulated neutrophils. Both acetoacetate and 3-hydroxybutyrate have suppressive effect on the respiratory burst measured by luminol-enhanced chemiluminescence. Through measurements of hypochlorous acid production, using neutrophils or the myeloperoxidase/H2O2/Cl- system, it was found that acetoacetate but not 3-hydroxybutyrate is able to inhibit the generation of this antimicrobial oxidant. The superoxide anion scavenging properties were confirmed by ferricytochrome C reduction and lucigenin-enhanced chemiluminescence assays. However, ketone bodies did not alter the rate of oxygen uptake by stimulated neutrophils, measured with an oxygen electrode. A strong inhibition of the expression of the cytokine IL-8 by cultured neutrophils was also observed; this is discussed with reference to the antioxidant-like property of acetoacetate. © 2004 Pharmaceutical Society of Japan.

The success rate of immediate implant placement of mandibular molars: A clinical and radiographic retrospective evaluation between 2 and 8 years

Background: Dental implants, indicated for re-establishing both mastigatory and aesthetic functions, can be placed in the sockets immediately after tooth extraction. Most studies investigate the anterior and upper regions of the dental arch, whereas few examine longitudinal appraisal of immediate implant installation in the mandibular molar region. Objective: The aim of this retrospective study was to evaluate the success rate of immediate dental implants placement in mandibular molars within a follow-up period as long as 8 years. Materials and methods: Seventy-four mandibular molar implants after non-traumatic tooth extraction between 2002 and 2008 were examined in the study. All implants were evaluated radiographically immediately after prosthesis placement, 1 year after implantation, and by the end of the experimental period, in 2010. Clinical evaluation was done according to [Albrektsson et al. (1986) The International Journal of Oral & Maxillofacial Implants, 1, 11-25] success criteria for marginal bone loss. The mean bone losses, calculated as the difference between the final evaluation measures and those taken by the end of the first year of implant, were compared using Kruskal-Wallis test with a significance level of 5%. Results: All implants presented clinical and radiographic stable conditions, that is, 100% success rate. Significant bone loss was not found between final evaluation and that of the first functional year (P > 0.05). Conclusion: Immediate implant placement of mandibular molars proved to be a viable surgical treatment given the high success rate up to 8 years after implantation. © 2012 John Wiley & Sons A/S.

Effects of fasting and refeeding on the metabolic functions of the turtle kinosternon scorpioides (linnaeus, 1766) raised in captivity

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)