Fernando Luiz Pereira de Oliveira

Self-oriented control charts for efficient monitoring of mean vectors.

Abstract This work presents a procedure for monitoring the centre of multivariate processes by optimising the noncentrality parameter with respect to the maximum separability between the in- and out-of-control states. Similarly to the Principal Component Analysis, this procedure is a linear transformation but using a different criterion which maximises the trace of two scatter matrices. The proposed linear statistic is self-oriented in the sense that no prior information is given, then it is monitored by two types of control charts aiming to identify small and intermediate shifts. As the control charts performances depend only on the noncentrality parameter, comparisons are made with traditional quadratic approaches, such as the Multivariate Cumulative Sum (MCUSUM), the Multivariate Exponentially Weighted Moving Average (MEWMA) and Hotelling’s T 2 control chart. The results show that the proposed statistic is a solution for the problem of finding directions to be monitored without the need of selecting eigenvectors, maximising efficiency with respect to the average run length.

THE CONSUMPTION OF ACAI PULP CHANGES THE CONCENTRATIONS OF PLASMINOGEN ACTIVATOR INHIBITOR-1 AND EPIDERMAL GROWTH FACTOR (EGF) IN APPARENTLY HEALTHY WOMEN.

INTRODUCTION obesity, characterized by adiposity excess, is associated with endothelial dysfunction and possible inflammatory state with release of cytokines that determine endothelial function and can trigger chronic diseases. The dietary pattern are associated with the synthesis these cytokines. Fruits as the acai, which is rich in flavonoids, have a direct and beneficial effect on the control of this inflammatory process through the exercised antioxidant capacity. OBJECTIVE to evaluate the effect of acai pulp consumption on the inflammatory markers, anthropometric measurements, body composition, biochemical and dietary parameters in healthy women. METHODS forty women, were divided in 25 eutrophic and 15 with overweight. They intaked 200 g of acai pulp during 4 weeks. Anthropometric measurements, body composition, inflammatory markers, biochemical data, dietary intake and dietary antioxidants capacity were evaluated before and after the intervention. RESULTS AND DISCUSSION after the intervention, there was significant increase of EGF (p = 0.021) and PAI- 1(p = 0.011) in overweight women. Moreover, there was increase in body weight (p = 0.031), body mass index (p = 0.028), percentage of truncal fat (p = 0.003) and triceps skinfold thickness (p = 0.046) in eutrophic women. However, the skinfold thickness (p = 0.018) and total body fat (p = 0.016) decreased in overweight women. There was reduction of total protein (p = 0.049) due to the globulin reduction (p = 0.005), but the nutritional status was maintained in eutrophic group. CONCLUSION the intake of 200g acai pulp, modulated the EGF and PAI-1 expression, possibly by modulation of acai on the parameters of body composition, dietary, clinical, biochemical and inflammatory, led to a redistribution and resizing of body fat of the trunk area, and presumably increased visceral fat.

Data-driven inference for the spatial scan statistic

BackgroundKulldorffs spatial scan statistic for aggregated area maps searches for clusters of cases without specifying their size (number of areas) or geographic location in advance. Their statistical significance is tested while adjusting for the multiple testing inherent in such a procedure. However, as is shown in this work, this adjustment is not done in an even manner for all possible cluster sizes.ResultsA modification is proposed to the usual inference test of the spatial scan statistic, incorporating additional information about the size of the most likely cluster found. A new interpretation of the results of the spatial scan statistic is done, posing a modified inference question: what is the probability that the null hypothesis is rejected for the original observed cases map with a most likely cluster of size k, taking into account only those most likely clusters of size k found under null hypothesis for comparison? This question is especially important when the p-value computed by the usual inference process is near the alpha significance level, regarding the correctness of the decision based in this inference.ConclusionsA practical procedure is provided to make more accurate inferences about the most likely cluster found by the spatial scan statistic.

Anti-helminthic activity of Momordica charantia L. against Fasciola hepatica eggs after twelve days of incubation in vitro.

Fasciolosis, a parasitic disease caused by the trematode Fasciola hepatica underreported is expanding both in human and animal population, throughout the world. The constant use of synthetic drugs to treat this condition has led to the natural selection of resistant strains of the parasite. Hence, there is a growing focus on the potential anti-helminthic properties of medicinal plants and phytopharmaceuticals. The current study assessed the potential anti-fasciolicide action of Momordica charantia leaf extracts and fractions on the eggs of F. hepatica parasites. The lyophilized crude extract (CE) of M. charantia leaves and its sub-fractions, obtained from liquid-liquid partitioning with organic solvents, were analysed by High Performance Liquid Chromatography (HPLC), suspended in 1% DMSO and used in in vitro tests. Quadruplicates of 50F. hepatica eggs were incubated at 23°C with M. charantia leaf CE in different concentrations. After 12days no larvae were formed in eggs incubated with CE concentrations above 12.5mg/mL. Eggs incubated with CE sub-fractions at concentrations of 1000, 100, 10, 1, 0.1, 0.01μg/mL affected embryonic development, with n-butanol presenting the strongest inhibition of miracidia formation. In contrast, on the 12th day, 90% of the miracidia hatched in the control experiments using 0.03% DMSO whereas embryogenesis was completely abolished with any concentration of albendazole sulphoxide ABZ(SO). Chemical analysis of the CE and sub-fractions revealed a prominent presence of flavonoids. HPLC-MS confirmed Quercetin to be one of the main flavonoids present in the CE and the n-butanol subfraction. This is the first study to analyse the potential anti-fasciolicide action of M. charantia leaf CE and subfractions.

Heart rate variability in shift workers: responses to orthostatism and relationships with anthropometry, body composition, and blood pressure.

In order to investigate the response of heart rate variability (HRV) components to postural change and their association with cardiovascular risk factors in shift workers, a cross-sectional study with 438 Brazilian males rotating shift workers was done. Anthropometric, body composition, and clinical measures were collected. Electrocardiogram was recorded for 3 minutes, in the supine and orthostatic position, and HRV components were extracted. Descriptive analyses showed that mean values of body mass index, waist circumference (WC), waist-to-height ratio, visceral fat area (VFA), and blood pressure (BP) were higher than the reference values. In the regression model, age, WC, VFA, and systolic BP showed negative association with HRV components. These findings suggest the need for determining effective strategies for the evaluation and promotion of health among shift workers focused on the altered variables.

An Item Response Theory approach to spatial cluster estimation and visualization

The scan statistic is widely used in spatial cluster detection applications of inhomogeneous Poisson processes. The most popular variant of the spatial scan is the circular scan. However, such approach has several limitations, in particular, the circular window is not suitable to make the correct description of irregularly shaped and/or unconnected clusters. Additionally, such methodology does not incorporate the tools needed for quantifying the uncertainty in the description of the most likely cluster in the analysis. In the present work we build upon the previously proposed methodology called intensity function a more efficient and accurate way of defining the uncertainty in the identification of spatial clusters using Item Response Theory ideas. Using simulated data we show that the proposed method can correctly identify primary, secondary and irregular clusters.

Association between nutritional status, C-reactive protein, adiponectin and HOMA-AD in Brazilian children

INTRODUCTION In children, the presence of obesity is a major risk factor for the occurrence of cardiovascular diseases on the adulthood. OBJECTIVE To evaluate the association of anthropometry, body composition, clinical variables and biochemical profile with C-reactive protein and adiponectin levels, and insulin resistance in children in the municipality of Nova Era, Brazil. METHODS Nested case-control study following a crosssectional study. We evaluated 178 children, 57 of them classified as obese and 121 as normal-weight from a population of 1024 schoolchildren 6 to 10 years old: Blood samples were collected after 12-hour fast to obtain serum and plasma. We collected anthropometric and body composition measures, systolic and diastolic blood pressure data. Sexual maturation was assessed according to the stage of sexual development. We performed Students t-test, Mann-Whitney U test, Pearsons correlation, Spearmans test and multiple linear regression analysis. Independent variables with p < 0.05 were included in the multiple regression model. Residual analysis was performed to assess model validity. RESULTS Among obese children, C-reactive protein levels were associated with triacylglycerol levels and body fat percentage estimated by skinfold thickness (R2 adjusted = 27.6%, p < 0.001). Adiponectin was associated with HOMA-IR, HOMAAD and body fat percentage estimated by skinfold thickness (R2 adjusted = 75.5%, p < 0.001). HOMA-AD index was associated with HOMA-IR, adiponectin, systolic blood pressure and weight (R2 adjusted = 90.7%, p < 0.001). CONCLUSION Significant associations were found between body composition, anthropometry, clinical variables, biochemical profile and adiponectin and C-reactive protein levels and insulin resistance in obese and normal-weight children.

Selective transfer in the acquisition of English double object constructions by Brazilian learners

The present study investigates the acquisition of the English double object constructions (GOLDBERG, 1995) by Brazilian learners. We hypothesize that, due to first language (L1) influences, the prepositional ditransitive construction (John gave a book to Mary) will be acquired earlier, while the ditransitive construction (John gave Mary a book) will be part of the learner’s interlanguages (SELINKER, 1972) only at the advanced level of proficiency. We also hypothesize that learners may transfer (ODLIN, 1989) the placement of the object pronoun in pre-verbal position from their L1 to their interlanguage in early stages of acquisition (Joao me deu um livro / *John me gave a book). We test our hypotheses by comparing the performance of three groups of learners (beginning, intermediate, and advanced) and native speakers of English on an acceptability judgment task used as a measure of learnability and generalization. Results confirm the order of acquisition of the English double object constructions predicted for native speakers of Brazilian Portuguese. Moreover, results suggest that, although mother tongue influences may have taken place, they do not do so pervasively, but rather selectively, corroborating the proposal by Kellerman (1983).

Cohort Profile: The Cohort of Universities of Minas Gerais (CUME)

Cohort Profile: The Cohort of Universities of Minas Gerais (CUME) Ana Luiza Gomes Domingos, Aline Elizabeth da Silva Miranda, Adriano Marçal Pimenta, Helen Hermana Miranda Hermsdorff, Fernando Luiz Pereira de Oliveira, Luana Caroline dos Santos, Aline Cristine Souza Lopes, Miguel Ángel Martı́nez González and Josefina Bressan* Department of Nutrition and Health, Universidade Federal de Viçosa (UFV), Viçosa, Brazil, Department of Maternal-Child Nursing and Public Health, School of Nursing, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil, Department of Statistics, Universidade Federal de Ouro Preto (UFOP), Ouro Preto, Brazil, Department of Nutrition, School of Nursing, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil, Department of Preventive Medicine and Public Health, School of Medicine, University of Navarra (UNAV), Pamplona, Spain, IdiSNA, Navarra Institute for Health Research, Pamplona, Spain, CIBERobn Physiopathology of Obesity and Nutrition, Institute of Health Carlos III (ISCIII), Madrid, Spain and Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA, USA

Uma proposta para identificação de outliers multivariados

The identification of outliers plays an important role in the statistical analysis, since such observations may contain important information regarding the hypotheses of the study. If classical statistical models are blindly applied to data containing atypical values, the results may be misleading and mistaken decisions can be made. Moreover, in practical situations, the outliers themselves are often the special points of interest and their identification may be the main objective of the investigation. In this way, it was proposed to propose a technique of detection of multivariate outliers, based on cluster analysis and to compare this technique with the method of identification of outliers via Mahalanobis Distance. For data generation, Monte Carlo method simulation and the mixed multivariate normal distribution technique were used. The results presented in the simulations showed that the proposed method was superior to the Mahalanobis method for both sensitivity and specificity, that is, it presented greater ability to correctly diagnose outliers and non-outliers individuals. In addition, the proposed methodology was illustrated with an application in real data from the health area.