43 resultados para chi square distribution

em Biblioteca Digital da Produção Intelectual da Universidade de São Paulo


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The objective of the present work was to propose a method for testing the contribution of each level of the factors in a genotypes x environments (GxE) interaction using multi-environment trials analyses by means of an F test. The study evaluated a data set, with twenty genotypes and thirty-four environments, in a block design with four replications. The sum of squares within rows (genotypes) and columns (environments) of the GxE matrix was simulated, generating 10000 experiments to verify the empirical distribution. Results indicate a noncentral chi-square distribution for rows and columns of the GxE interaction matrix, which was also verified by the Kolmogorov-Smirnov test and Q-Q plot. Application of the F test identified the genotypes and environments that contributed the most to the GxE interaction. In this way, geneticists can select good genotypes in their studies.

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The asymptotic expansion of the distribution of the gradient test statistic is derived for a composite hypothesis under a sequence of Pitman alternative hypotheses converging to the null hypothesis at rate n(-1/2), n being the sample size. Comparisons of the local powers of the gradient, likelihood ratio, Wald and score tests reveal no uniform superiority property. The power performance of all four criteria in one-parameter exponential family is examined.

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We derive asymptotic expansions for the nonnull distribution functions of the likelihood ratio, Wald, score and gradient test statistics in the class of dispersion models, under a sequence of Pitman alternatives. The asymptotic distributions of these statistics are obtained for testing a subset of regression parameters and for testing the precision parameter. Based on these nonnull asymptotic expansions, the power of all four tests, which are equivalent to first order, are compared. Furthermore, in order to compare the finite-sample performance of these tests in this class of models, Monte Carlo simulations are presented. An empirical application to a real data set is considered for illustrative purposes. (C) 2012 Elsevier B.V. All rights reserved.

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OBJETIVO: Comparar os resultados maternos e neonatais em mulheres de baixo risco atendidas em centro de parto normal peri-hospitalar e hospital. MÉTODOS: Estudo transversal com amostra representativa de mulheres de baixo risco atendidas em São Paulo, SP, de 2003 a 2006. Foram incluídas 991 mulheres que tiveram o parto no centro de parto normal e 325 que deram à luz no hospital. Os dados foram obtidos dos prontuários. A análise comparativa foi realizada para o total de mulheres e estratifi cada segundo a paridade. Foram aplicados os testes qui-quadrado e exato de Fisher. RESULTADOS: Houve distribuição homogênea das mulheres segundo a paridade (45,4% nulíparas e 54,6% mulheres com um ou mais partos anteriores). Foram encontradas diferenças estatisticamente signifi cantes em relação às seguintes intervenções: amniotomia (mais freqüente entre nulíparas do hospital); utilização de ocitocina no trabalho de parto e utilização de analgésico no pós-parto (mais freqüentes no hospital entre as mulheres de todas as paridades). A taxa de episiotomia foi maior entre as nulíparas, tanto no centro de parto como no hospital. Houve maior freqüência de intervenções com o neonato no hospital: aspiração das vias aéreas superiores, aspiração gástrica, lavagem gástrica, oxigênio por máscara aberta. Também ocorreram com mais freqüência no hospital bossa serossanguínea, desconforto respiratório e internação na unidade neonatal. Não houve diferença nos valores de Apgar no quinto minuto nem casos de morte materna ou perinatal. CONCLUSÕES: A assistência no centro de parto normal foi realizada com menos intervenções e com resultados maternos e neonatais semelhantes aos do hospital.

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Purpose. To assess the impact of a six-month stage-based intervention on fruit and vegetable intake, regarding perceived benefits and barriers, and self-efficacy among adolescents. Design. Randomized treatment-control, pre-post design. Subjects/ Setting. Schools were randomized between control and experimental groups. 860 adolescents from ten public schools in Bras ' ilia, Federal District, Brazil were evaluated at baseline; 771 (81%) completed the study. Intervention. Experimental group received monthly magazines and newsletters aimed at promotion of healthy eating. Measures. Self-reported fruit and vegetable intake, stages of change, self-efficacy and decisional balance scores were evaluated at baseline and post-intervention in both groups. Analysis. The effectiveness of the intervention was evaluated using the analysis of covariance model (ANCOVA) and repeated measurement analysis by means of weighted least squares. Comparison between the proportions of adolescents who advanced through the stages during the intervention was performed using the Mantel-Haenszel chi-square test. Results. After adjusting for sex and age, study variables showed no modifications through the proposed intervention. There was no statistical difference in participant mobility in the intervention and control groups between the stages of change, throughout the study. Conclusion. A nutritional intervention based exclusively on distribution of stage-matched printed educational materials was insufficient to change adolescents' dietary behavior.

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O objetivo foi comparar conhecimento de homens idosos ao de adultos jovens sobre Aids, considerando escolaridade. Estudo epidemiológico, descritivo e de corte transversal, em que foram analisadas informações de 30 idosos e 62 adultos jovens sobre conceito, transmissão, prevenção, diagnóstico e tratamento de Aids, investigadas por entrevista estruturada baseada em questionário validado padronizado. Para análise de contingência e de variância, empregaram-se distribuições de frequências e testes de Qui quadrado ou exato de Fisher e teste t de Student ou Mann-Whitney em nível de significância de 0,05. Foram empregados o teste de Mantel-Haenszel, em nível de significância de 0,05, e os Odds Ratio com intervalos de confiança a 95%, para influência da escolaridade. Constataram-se percepção individual de boa saúde maior em jovens (61,3% contra 43,3% dos idosos) e atividade sexual maior em idosos (80% contra 62,9% dos jovens). Apesar disso foi menos frequente idosos afirmarem conhecimento satisfatório sobre Aids (26,7% contra 80,6% dos jovens); história de teste de HIV (13,3% contra 24,2% dos jovens) e ter recebido orientação sobre Aids (36,7% dos idosos e 98,4% dos jovens). Os idosos tinham informação insuficiente sobre HIV/Aids comparados a adultos jovens, reforçando a necessidade de maior atenção à população idosa.

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Abstract Background Assuming a higher risk of latent tuberculosis (TB) infection in the population of Rio de Janeiro, Brazil, in October of 1998 the TB Control Program of Clementino Fraga Filho Hospital (CFFH) routinely started to recommend a two-step tuberculin skin test (TST) in contacts of pulmonary TB cases in order to distinguish a boosting reaction due to a recall of delayed hypersensitivity previously established by infection with Mycobacterium tuberculosis (M.tb) or BCG vaccination from a tuberculin conversion. The aim of this study was to assess the prevalence of boosted tuberculin skin tests among contacts of individuals with active pulmonary tuberculosis (TB). Methods Retrospective cohort of TB contacts ≥ 12 years old who were evaluated between October 1st, 1998 and October 31st 2001. Contacts with an initial TST ≤ 4 mm were considered negative and had a second TST applied after 7–14 days. Boosting reaction was defined as a second TST ≥ 10 mm with an increase in induration ≥ 6 mm related to the first TST. All contacts with either a positive initial or repeat TST had a chest x-ray to rule out active TB disease, and initially positive contacts were offered isoniazid preventive therapy. Contacts that boosted did not receive treatment for latent TB infection and were followed for 24 months to monitor the development of TB. Statistical analysis of dichotomous variables was performed using Chi-square test. Differences were considered significant at a p < 0.05. Results Fifty four percent (572/1060) of contacts had an initial negative TST and 79% of them (455/572) had a second TST. Boosting was identified in 6% (28/455). The mean age of contacts with a boosting reaction was 42.3 ± 21.1 and with no boosting was 28.7 ± 21.7 (p = 0.01). Fifty percent (14/28) of individuals whose test boosted met criteria for TST conversion on the second TST (increase in induration ≥ 10 mm). None of the 28 contacts whose reaction boosted developed TB disease within two years following the TST. Conclusion The low number of contacts with boosting and the difficulty in distinguishing boosting from TST conversion in the second TST suggests that the strategy of two-step TST testing among contacts of active TB cases may not be useful. However, this conclusion must be taken with caution because of the small number of subjects followed.

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Conclusions: Black individuals had greater prevalence of long face pattern, followed by Brown, White and Yellow individuals. The prevalence of long face pattern was 14.06% in which 13.39% and 0.68% belonged to moderate and severe subtypes, respectively.

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Background: Aortic aneurysm and dissection are important causes of death in older people. Ruptured aneurysms show catastrophic fatality rates reaching near 80%. Few population-based mortality studies have been published in the world and none in Brazil. The objective of the present study was to use multiple-cause-of-death methodology in the analysis of mortality trends related to aortic aneurysm and dissection in the state of Sao Paulo, between 1985 and 2009. Methods: We analyzed mortality data from the Sao Paulo State Data Analysis System, selecting all death certificates on which aortic aneurysm and dissection were listed as a cause-of-death. The variables sex, age, season of the year, and underlying, associated or total mentions of causes of death were studied using standardized mortality rates, proportions and historical trends. Statistical analyses were performed by chi-square goodness-of-fit and H Kruskal-Wallis tests, and variance analysis. The joinpoint regression model was used to evaluate changes in age-standardized rates trends. A p value less than 0.05 was regarded as significant. Results: Over a 25-year period, there were 42,615 deaths related to aortic aneurysm and dissection, of which 36,088 (84.7%) were identified as underlying cause and 6,527 (15.3%) as an associated cause-of-death. Dissection and ruptured aneurysms were considered as an underlying cause of death in 93% of the deaths. For the entire period, a significant increased trend of age-standardized death rates was observed in men and women, while certain non-significant decreases occurred from 1996/2004 until 2009. Abdominal aortic aneurysms and aortic dissections prevailed among men and aortic dissections and aortic aneurysms of unspecified site among women. In 1985 and 2009 death rates ratios of men to women were respectively 2.86 and 2.19, corresponding to a difference decrease between rates of 23.4%. For aortic dissection, ruptured and non-ruptured aneurysms, the overall mean ages at death were, respectively, 63.2, 68.4 and 71.6 years; while, as the underlying cause, the main associated causes of death were as follows: hemorrhages (in 43.8%/40.5%/13.9%); hypertensive diseases (in 49.2%/22.43%/24.5%) and atherosclerosis (in 14.8%/25.5%/15.3%); and, as associated causes, their principal overall underlying causes of death were diseases of the circulatory (55.7%), and respiratory (13.8%) systems and neoplasms (7.8%). A significant seasonal variation, with highest frequency in winter, occurred in deaths identified as underlying cause for aortic dissection, ruptured and non-ruptured aneurysms. Conclusions: This study introduces the methodology of multiple-causes-of-death to enhance epidemiologic knowledge of aortic aneurysm and dissection in São Paulo, Brazil. The results presented confer light to the importance of mortality statistics and the need for epidemiologic studies to understand unique trends in our own population.

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Abstract Background The application and better understanding of traditional and new breast tumor biomarkers and prognostic factors are increasing due to the fact that they are able to identify individuals at high risk of breast cancer, who may benefit from preventive interventions. Also, biomarkers can make possible for physicians to design an individualized treatment for each patient. Previous studies showed that trace elements (TEs) determined by X-Ray Fluorescence (XRF) techniques are found in significantly higher concentrations in neoplastic breast tissues (malignant and benign) when compared with normal tissues. The aim of this work was to evaluate the potential of TEs, determined by the use of the Energy Dispersive X-Ray Fluorescence (EDXRF) technique, as biomarkers and prognostic factors in breast cancer. Methods By using EDXRF, we determined Ca, Fe, Cu, and Zn trace elements concentrations in 106 samples of normal and breast cancer tissues. Cut-off values for each TE were determined through Receiver Operating Characteristic (ROC) analysis from the TEs distributions. These values were used to set the positive or negative expression. This expression was subsequently correlated with clinical prognostic factors through Fisher’s exact test and chi-square test. Kaplan Meier survival curves were also evaluated to assess the effect of the expression of TEs in the overall patient survival. Results Concentrations of TEs are higher in neoplastic tissues (malignant and benign) when compared with normal tissues. Results from ROC analysis showed that TEs can be considered a tumor biomarker because, after establishing a cut-off value, it was possible to classify different tissues as normal or neoplastic, as well as different types of cancer. The expression of TEs was found statistically correlated with age and menstrual status. The survival curves estimated by the Kaplan-Meier method showed that patients with positive expression for Cu presented a poor overall survival (p < 0.001). Conclusions This study suggests that TEs expression has a great potential of application as a tumor biomarker, once it was revealed to be an effective tool to distinguish different types of breast tissues and to identify the difference between malignant and benign tumors. The expressions of all TEs were found statistically correlated with well-known prognostic factors for breast cancer. The element copper also showed statistical correlation with overall survival.

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Introduction Approximately 20% JIA patients enters adulthood with clinically active disease and disabled, therefore work condition may be affected. Objectives To assess the prevalence of work disability among adult patients with JIA regularly attending a tertiary heumatology center and to determine possible associated risk factors. Methods This was a cross-sectional study that enrolled 43 JIA patients according to 2004 revised ILAR criteria. A questionnaire was developed in order to evaluate working status and labor activity: occupation, current/previous work, employment status and withdrawal rate were actively searched. Demographic data, JIA characteristics, clinical activity (DAS28>2.6), therapeutic intervention, comorbidities, physical activity, sedentarism (WHO definitions), functional class (1991 ACR criteria), HAQ and SF-36 were recorded. The prevalence of work disability was calculated using 95% confidence interval, and compared to all parameters; qualitative variables were analyzed using tests of association (chi-square test) and quantitative variables by Mann-Whitney or student test. Results Patients' mean age was 29+7.4 yrs (range 19-41) with mean JIA duration = 17.2+12.3 yrs (range 3-33); 63% were males and 37% females. JIA subtypes were 64% polyarticular, 11% oligoarticular, 9% systemic, 9% ERA, 2% extended oligoarticular, 2% psoriatic arthritis; 7% had uveitis. Serum RF was positive in 21% and ANA in 21%. The majority (72%, n = 31) of JIA patients were employed, whereas 28% (n = 12) were currently not working. In the latter group, 83% (10/12) were retired due to JIA related disability. Further analysis comparing those currently working vs. Those not working revealed similar age (25,3 yrs vs.29,5 yrs, p = 0,09). Although not significantly, most patients currently working had Poly onset JIA (22 vs. 6 p = 0,37), higher frequencies of good education level >12 yrs of school (31 vs.9, p = 0,38), functional class I (p = 0,96), practiced regular physical activity (9 vs. 0, p = 0,89), were singles (26 vs. 8, p = 0,15). Both groups had comparable HAQ and DAS 28 scores (0,62 vs. 0.59, p = 0,47 and 2,51 vs.2,07, p = 0,64) and similar arthroplasty rate (8 vs. 4, p = 0,427). Frequencies of hypertension (3 vs.1, p = 0,999), dyslipidemia (1 vs. 1, p = 0,125), diabetes (1 vs. 0 p = 0,999), depression (1 vs. 0, p = 0,999) and smokers (3 vs. 1, p = 0,99) were alike in both groups. Remarkably, employed patients had higher SF 36 mental health component (84.0 vs. 70.42, P = 0.01). Conclusion High prevalence of almost 1/3 work disability and of retirement due to disease related incapacity remain major problems for adult JIA individuals. We also identified worse mental health in employed patients indicating that further research is needed, in addition to intense affirmative disability actions in order to remove possible disabling barriers and to adapt restrictive environments for these patients. Moreover, enhanced strategies and policy for inclusion of JIA patients in the job market is urged.

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Abstract Background Eating disorder (ED) patients often have comorbidities with other psychiatric disorders, especially with mood disorders. Although recent studies suggest an intimate relationship between ED and bipolar disorder (BD), the study on a broader bipolar spectrum definition has not been done in this population. We aimed to study the occurrence of bipolar spectrum (BS) and comorbidities in eating disorder patients of a tertiary service provider. Methods Sixty-nine female patients diagnosed with anorexia nervosa, bulimia nervosa, or eating disorder not otherwise specified were evaluated. The assessment comprised the Structured Clinical Interview for DSM-IV Axis I Disorders (SCID-I), clinical criteria for diagnosis of the Zurich bipolar spectrum. Mann–Whitney tests compared means of continuous variables. The association between categorical variables and the groups was described using contingency tables and analyzed using the chi-square or Fisher's exact test. The level of significance alpha was set at 5%. Results The results showed that 68.1% of patients had comorbidity with bipolar spectrum, and this was associated with higher family income, proportion of married people, and comorbidity with substance use. The ED with BS group showed higher rates of substance use comorbidity (40.4%) than the ED without BS group (13.6%). Discussion These results showed that the bipolar spectrum is a common comorbidity in patients with eating disorders and is associated with correlates of clinical importance, notably the comorbidity with substance use. Due to the pattern of similarity between the groups with and without comorbid bipolar spectrum in relation to various outcomes evaluated, the identification of comorbidity can be difficult. However, the precise diagnosis and careful identification of clinical correlates may contribute to future advances in treating these conditions. Further studies are necessary to evaluate the association of other clinical correlates and its possible causal association.

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OBJETIVO: Estimar a prevalência e descrever a distribuição do tracoma entre escolares em municípios brasileiros. MÉTODOS: Estudo de corte transversal, usando amostragem por conglomerados, da população escolar dos municípios brasileiros com Índice de Desenvolvimento Humano-Municipal menor que a média nacional. O inquérito de prevalência de tracoma foi realizado pelo Ministério da Saúde entre 2002 e 2007. Foram selecionados 119.531 alunos de 2.270 escolas localizadas em 1.156 municípios. Os alunos foram submetidos ao exame ocular externo, com lupa (2,5X), para detecção de sinais clínicos de tracoma segundo critérios da OMS. Estimou-se a prevalência de tracoma segundo estado e em nível nacional, e seus respectivos intervalos de 95% de confi ança. Para a comparação de variáveis categóricas foram usados os testes do Qui-quadrado e do Qui-quadrado de tendência linear. RESULTADOS: Foram detectados 6.030 casos de tracoma, resultando em prevalência de 5,0% (IC95% 4,5;5,4). Não foi encontrada diferença signifi cante entre os sexos. A prevalência de tracoma foi de 8,2% entre menores de cinco anos de idade, diminuindo nas faixas etárias mais altas (p < 0,01). Houve diferença signifi cante entre as prevalências de tracoma na zona urbana e rural, 4,3% versus 6,2%, respectivamente (p < 0,01). Foram detectados casos em 901 municípios (77,7% da amostra), em todas as regiões do País. Em 36,8% dos municípios selecionados a prevalência foi superior a 5%. CONCLUSÕES: O estudo mostra que o tracoma é um importante problema de saúde pública no Brasil, contradizendo a crença de que a endemia estaria controlada no País. O inquérito realizado apresenta uma linha de base para avaliação das intervenções planejadas com vistas ao alcance da meta mundial de certifi cação da eliminação do tracoma como causa de cegueira no Brasil, até 2020.

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OBJECTIVE: The aim of this study was to assess the IgE serum levels in juvenile systemic lupus erythematosus patients and to evaluate possible associations with clinical and laboratory features, disease activity and tissue damage. METHODS: The IgE serum concentrations in 69 consecutive juvenile systemic lupus erythematosus patients were determined by nephelometry. IgG, IgM and IgA concentrations were measured by immunoturbidimetry. All patients were negative for intestinal parasites. Statistical analysis methods included the Mann-Whitney, chi-square and Fisher's exact tests, as well as the Spearman rank correlation coefficient. RESULTS: Increased IgE concentrations above 100 IU/mL were observed in 31/69 (45%) juvenile systemic lupus erythematosus patients. The mean IgE concentration was 442.0 +/- 163.4 IU/ml (range 3.5- 9936.0 IU/ml). Fifteen of the 69 patients had atopic disease, nine patients had severe sepsis and 56 patients presented with nephritis. The mean IgE level in 54 juvenile systemic lupus erythematosus patients without atopic manifestations was 271.6 +/- 699.5 IU/ml, and only nine of the 31 (29%) patients with high IgE levels had atopic disease. The IgE levels did not statistically differ with respect to the presence of atopic disease, severe sepsis, nephritis, disease activity, or tissue damage. Interestingly, IgE concentrations were inversely correlated with C4 levels ( r = -0.25, p = 0.03) and with the SLICC/ACR-DI score (r = -0.34, p = 0.005). The IgE concentration was also found to be directly correlated with IgA levels (r = 0.52, p = 0.03). CONCLUSIONS: The present study demonstrated for the first time that juvenile systemic lupus erythematosus patients have increased IgE serum levels. This increase in IgE levels was not related to allergic or parasitic diseases. Our results are in line with the hypothesis that high IgE levels can be considered a marker of immune dysregulation.

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OBJECTIVE To report our experience with silent ureteral stones and expose their true influence on renal function. METHODS We analyzed 506 patients who had undergone ureterolithotripsy from January 2005 to May 2010. Silent ureteral stones were calculi found in the absence of any specific or subjective ureteral stone-related symptoms. Of the 506 patients, 27 (5.3%) met these criteria (global cohort). All patients were assessed postoperatively with dimercaptosuccinic acid scintigraphy (DMSA). A difference in relative kidney function of >10% was considered abnormal. Pre- and postoperative comparative DMSA analyses were electively obtained for 9 patients (kidney function cohort). A t test was used to assess the numeric variables, and the chi-square test or Fisher's exact test was used for categorical variables. Two-tailed P < .05 was considered statistically significant. RESULTS Stones were diagnosed by radiologic abdominal evaluation for nonurologic diseases in 40% and after previous nephrolithiasis treatment in 33%. The primary therapy was ureterolithotripsy in 88%. The mean follow-up time was 23 months. The overall ureteral stone-free rate after 1 and 2 procedures was 96% and 100%, respectively. In the global cohort, the mean pre- and postoperative serum creatinine levels were similar (P = .39), and the mean postoperative function on DMSA was 31%. In the kidney function cohort, no difference was found between the pre-and postoperative DMSA findings (22% +/- 12.1% vs 20% +/- 11.8%; P = .83) and serum creatinine (0.8 +/- 0.13 mg/dL vs 1.0 +/- 0.21 mg/dL; P = .45). CONCLUSION Silent ureteral stones are associated with decreased kidney function present at the diagnosis. Hydronephrosis tends to diminish after stone removal, and kidney function remains unaltered. UROLOGY 79: 304-309, 2012. (C) 2012 Elsevier Inc.