Uma avaliação do uso de um modelo contínuo na análise de dados discretos de sobrevivência

Propomos neste trabalho uma comparação dos resultados de análises de dados de sobrevivência utilizando dois modelos equivalentes, sendo um contínuo e outro discreto. Diz-se “modelos equivalentes” pois será utilizado um modelo cuja formulação original é contínua e através deste modelo, será gerado um modelo discreto correspondente

Analysis of the camoufage effect in time of segregation in texturized regions using the Cox proportional hazard model

Os seres humanos possuem visão tricromática. No entanto, variações nos genes podem provocar defciências na visão em cores levando ao dicromatismo. O objetivo deste trabalho foi verifcar a real efciência dos dicromatas na quebra de camufagem por cor. Participaram desse estudo nove indivíduos daltônicos e a resposta foi o tempo de segregação de alvos camufados. O interesse foi comparar o tempo de resposta em várias condições de camufagem e a análise dos dados foi realizada utilizando o modelo de riscos proporcionais de Cox. ____________________________________________________________________________________________________________________ ABSTRACTHumans have trichromatic vision. However variations in gene can cause defciency in color vision resulting to dichromatism. The aim of this work was to verify the real effciency of dichromats to break colour camoufage. Total of nine colour-blind individuals participated in this study and the variable considered was the time to segregation of camoufaged targets. The interest was to compare the response time in several conditions of camoufage and the analysis was performed using the Cox proportional hazard model

CONSEQUENCES OF ALCOHOL ABUSE/DEPENDENCE IN BRAZIL: DISABILITY-ADJUSTED LIFE YEARS (DALY)

This study estimated the burden of alcohol use in Disability-Adjusted Life Years (DALY) for Brazil. The measures of DALY combines the measures of Years of Life Lost (YLL) and Years Lived with Disability (YLD), based on methodology of the Global Burden of Disease (GBD) and were presented using the rate of 1:10,000. Alcohol use was defined by ICD-10 F10-F10.9. We used outpatient treatment, admissions and mortality data and the disability weights specific for alcohol according with GBD to calculate the DALY-relevant measures. The total value of DALY in Brazil due to the alcohol use was 32.05, similar to what we observed in YLD total value [31.60] and different of the measure of the YLL total value [0.45]. There is important difference in DALY’s value between gender, being the biggest at the age group 40-44 [158.10 male and 34.03 female]. The biggest loss of DALY’s total value is at the 44 age group with 158.01 years. The impact of the DALY due to alcohol use represents the need to refine existing actions in prevention and treatment, seeking the search for better strategies that promote more responsible alcohol use and decrease individual and social harms

Two mechanisms of oral malodor inhibition by zinc ions

Objectives The aim of this study was to reveal the mechanisms by which zinc ions inhibit oral malodor. Material and Methods The direct binding of zinc ions to gaseous hydrogen sulfide (H2S) was assessed in comparison with other metal ions. Nine metal chlorides and six metal acetates were examined. To understand the strength of H2S volatilization inhibition, the minimum concentration needed to inhibit H2S volatilization was determined using serial dilution methods. Subsequently, the inhibitory activities of zinc ions on the growth of six oral bacterial strains related to volatile sulfur compound (VSC) production and three strains not related to VSC production were evaluated. Results Aqueous solutions of ZnCl2, CdCl2, CuCl2, (CH3COO)2Zn, (CH3COO)2Cd, (CH3COO)2Cu, and CH3COOAg inhibited H2S volatilization almost entirely. The strengths of H2S volatilization inhibition were in the order Ag+ >; Cd2+ >; Cu2+ >; Zn2+. The effect of zinc ions on the growth of oral bacteria was strain-dependent. Fusobacterium nucleatum ATCC 25586 was the most sensitive, as it was suppressed by medium containing 0.001% zinc ions. Conclusions Zinc ions have an inhibitory effect on oral malodor involving the two mechanisms of direct binding with gaseous H2S and suppressing the growth of VSC-producing oral bacteria

ESTIMAÇÃO INTERVALAR PARA OS PARÂMETROS DO MODELO EXPONENCIAL DISCRETO: UMA APLICAÇÃO PARA DADOS DE SOBREVIVÊNCIA

Este trabalho apresenta a utilização do modelo exponencial discreto (modelo geométrico) na análise de dados discretos, em particular, para dados de sobrevivência. Foram apresentadas a estimativa pontual e seus respectivos intervalos de confiança para o parâmetro do modelo. Este trabalho considerou a técnica de reamostragem bootstrap (paramétrica e não-paramétrica) como um procedimento alternativo adequado para construção de intervalos de confiança para o parâmetro do modelo exponencial discreto. A metodologia foi ilustrada através de dados simulados e por meio de uma aplicação em um conjunto de dados reais sobre o tempo até a rehospitalização de pacientes com esquizofrenia. Todos os procedimentos de estimação e simulações foram realizados através do software livre R

Rate of Heat Transfer between a Fluidized Bed and the Tube Wall at Higher Temperature

The heat transfer coefficient between a fluidized bed and the tube wall, hw, was measured in the temperature range of 500° to 800°C. Quartz and fused alumina particles were fluidized in the air stream. The coefficient hw was obtained between 70 and 800 kcal/m²·hr·°C. It increases with the flow rate of air. The effects of bed temperature and heat content and size of the particles on hw were imperceptible. By comparing the heat transfer coefficients obtained in this work with those at lower temperatures below 200°C, the difference between both coefficients was not significant

Brazilian vegetarians diet quality markers and comparison with the general population : a nationwide cross-sectional study

Background Vegetarianism is an increasingly common practice worldwide. Despite good evidence from other countries regarding vegetarians’ diet quality, data from the Brazilian population is still scarce. Objective To characterize the vegetarian Brazilian population and evaluate their diet quality compared to the general Brazilian population. Methods We performed a nationwide cross-sectional study using an online self-administered questionnaire, previously validated for the Brazilian population, to evaluate diet quality markers of vegetarians. The invitation to participate in the survey was spread nationwide, aimed at vegetarian communities. Individuals who considered themselves vegetarians and were at least 18 years old were eligible to participate. The results on regular intake and intake adequacy were compared among vegetarians and between genders using the Pearson’s chi-square test. The body mass index (BMI) were analyzed by the Analysis of Variance (ANOVA) followed by Tukey post-hoc test. The Kolmogorov-Smirnov test verified normality. All analyses considered bilateral hypotheses and a significance level of 5% (p <0.05). Results Brazilian vegetarians presented better diet quality markers, such as higher regular weekly intake and adequate daily intake of fruits and vegetables, and lower regular intake of soft drinks when compared to the general Brazilian population. Vegetarians also presented a proportionally higher consumption of natural foods and lower consumption of processed foods. Among vegetarians, a higher proportion of vegans showed positive results regarding diet markers analysis, when compared to vegetarians, pesco-vegetarians, and semi-vegetarians. Conclusions Vegetarians showed better results of diet adequacy when compared to the general population in Brazil, and vegans fared better when compared with other vegetarians. Despite the good results found, a large proportion of the participants still did not achieve the fruits and vegetables daily intake, according to the World Health Organization recommendations

Inferência bayesiana no modelo Weibull discreto em dados com presença de censura

Este trabalho apresenta uma inferência bayesiana da distribuição Weibull discreta em dados com presença de censuras. Foi proposto também um teste de significância genuinamente bayesiano (FBST - Full Bayesian Significance Test) para testar seu parâmetro de forma. Amostras da distribuição a posteriori dos parâmetros foram obtidas por meio de simulações via Markov Chain Monte Carlo (MCMC). A metodologia desenvolvida foi ilustrada em simulações e aplicada em um conjunto de dados sobre o tempo de sobrevivência de homens diagnosticados com AIDS. Todas as simulações e obtenções das estimativas foram realizadas com a linguagem R.This work presents a bayesian inference on discrete Weibull distribution with censored data. A Full Bayesian Significance Test (FBST) was proposed to test the shape parameter of model. Samples from the posterior distributions of parameters were numerically obtained by Markov Chain Monte Carlo (MCMC) simulations. This methodology was illustrated using simulated data and by application on a real database of survival times of men diagnosed with AIDS. All simulations and estimates were performed in R language