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Search Results: 1 - 10 of 646876 matches for " Carlos Alberto de Bragan?a Pereira "
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Evidence and Credibility: Full Bayesian Significance Test for Precise Hypotheses
Carlos Alberto De Bragana Pereira,Julio Michael Stern
Entropy , 1999, DOI: 10.3390/e1040099
Abstract: A Bayesian measure of evidence for precise hypotheses is presented. The intention is to give a Bayesian alternative to significance tests or, equivalently, to p-values. In fact, a set is defined in the parameter space and the posterior probability, its credibility, is evaluated. This set is the "Highest Posterior Density Region" that is "tangent" to the set that defines the null hypothesis. Our measure of evidence is the complement of the credibility of the "tangent" region.
Weight of evidence
Aguiar, Alexandre Santos;Pereira, Carlos Alberto de Bragana;
Revista do Colégio Brasileiro de Cirurgi?es , 2008, DOI: 10.1590/S0100-69912008000200013
Abstract: evidence-based medicine (ebm) has become a major source of medical knowledge. it handles complexities of virtually every method or technique used in research. the knowledge on how the ebm researcher retrieves information, judges for relevance and analyzes derived data is invaluable for the skillful reader of medical scientific reports.
Sequential allocation to balance prognostic factors in a psychiatric clinical trial
Fossaluza, Victor;Diniz, Juliana Belo;Pereira, Basilio de Bragana;Miguel, Eurípedes Constantino;Pereira, Carlos Alberto de Bragana;
Clinics , 2009, DOI: 10.1590/S1807-59322009000600005
Abstract: objective: this paper aims to describe and discuss a minimization procedure specifically designed for a clinical trial that evaluates treatment efficacy for ocd patients. method: aitchison's compositional distance was used to calculate vectors for each possibility of allocation in a covariate adaptive method. two different procedures were designed to allocate patients in small blocks or sequentially one-by-one. results: we present partial results of this allocation procedure as well as simulated data. in the clinical trial for which this procedure was developed, successful balancing between treatment arms was achieved. separately, in an exploratory analysis, we found that if the arrival order of patients was altered, most patients were allocated to a different treatment arm than their original assignment. conclusion: our results show that the random arrival order of patients determine different assignments and therefore maintains the unpredictability of the allocation method. we conclude that our proposed procedure allows for the use of a large number of prognostic factors in a given allocation decision. our method seems adequate for the design of the psychiatric trials used as models. trial registrations are available at clinicaltrials.gov nct00466609 and nct00680602.
Detection of determinant genes and diagnostic via Item Response Theory
Tavares, Héliton Ribeiro;Andrade, Dalton Francisco de;Pereira, Carlos Alberto de Bragana;
Genetics and Molecular Biology , 2004, DOI: 10.1590/S1415-47572004000400033
Abstract: this work presents a method to analyze characteristics of a set of genes that can have an influence in a certain anomaly, such as a particular type of cancer. a measure is proposed with the objective of diagnosing individuals regarding the anomaly under study and some characteristics of the genes are analyzed. maximum likelihood equations for general and particular cases are presented.
A new media optimizer based on the mean-variance model
Fernandez, Pedro Jesus;Lauretto, Marcelo de Souza;Pereira, Carlos Alberto de Bragana;Stern, Julio Michael;
Pesquisa Operacional , 2007, DOI: 10.1590/S0101-74382007000300003
Abstract: in the financial markets, there is a well established portfolio optimization model called generalized mean-variance model (or generalized markowitz model). this model considers that a typical investor, while expecting returns to be high, also expects returns to be as certain as possible. in this paper we introduce a new media optimization system based on the mean-variance model, a novel approach in media planning. after presenting the model in its full generality, we discuss possible advantages of the mean-variance paradigm, such as its flexibility in modeling the optimization problem, its ability of dealing with many media performance indices - satisfying most of the media plan needs - and, most important, the property of diversifying the media portfolios in a natural way, without the need to set up ad hoc constraints to enforce diversification.
Bayesian test of significance for conditional independence: The multinomial model
Pablo de Morais Andrade,Julio Michael Stern,Carlos Alberto de Bragana Pereira
Statistics , 2013, DOI: 10.3390/e16031376
Abstract: Conditional independence tests (CI tests) have received special attention lately in Machine Learning and Computational Intelligence related literature as an important indicator of the relationship among the variables used by their models. In the field of Probabilistic Graphical Models (PGM)--which includes Bayesian Networks (BN) models--CI tests are especially important for the task of learning the PGM structure from data. In this paper, we propose the Full Bayesian Significance Test (FBST) for tests of conditional independence for discrete datasets. FBST is a powerful Bayesian test for precise hypothesis, as an alternative to frequentist's significance tests (characterized by the calculation of the \emph{p-value}).
Assessment of anxiety and quality of life in fibromyalgia patients
Pagano, Tathiana;Matsutani, Luciana Akemi;Ferreira, Elisabeth Alves Gon?alves;Marques, Amélia Pasqual;Pereira, Carlos Alberto de Bragana;
Sao Paulo Medical Journal , 2004, DOI: 10.1590/S1516-31802004000600005
Abstract: context: fibromyalgia is a syndrome characterized by chronic, diffuse musculoskeletal pain, and by a low pain threshold at specific anatomical points. the syndrome is associated with other symptoms such as fatigue, sleep disturbance, morning stiffness and anxiety. because of its chronic nature, it often has a negative impact on patients' quality of life. objective: to assess the quality of life and anxiety level of patients with fibromyalgia. type of study: cross-sectional. setting: rheumatology outpatient service of hospital das clínicas (medical school, universidade de s?o paulo). methods: this study evaluated 80 individuals, divided between test and control groups. the test group included 40 women with a confirmed diagnosis of fibromyalgia. the control group was composed of 40 healthy women. three questionnaires were used: two to assess quality of life (fiq and sf-36) and one to assess anxiety (stai). they were applied to the individuals in both groups in a single face-to-face interview. the statistical analysis used student's t test and pearson's correlation test (r), with a significance level of 95%. also, the pearson chi-squared statistics test for homogeneity, with yates correction, was used for comparing schooling between test and control groups. results: there was a statistically significant difference between the groups (p = 0.000), thus indicating that fibromyalgia patients have a worse quality of life and higher levels of anxiety. the correlations between the three questionnaires were high (r = 0.9). discussion: this study has confirmed the efficacy of fiq for evaluating the impact of fibromyalgia on the quality of life. sf-36 is less specific than fiq, although statistically significant values were obtained when analyzed separately, stai showed lower efficacy for discriminating the test group from the control group. the test group showed worse quality of life than did the control group, which was demonstrated by both fiq and sf-36. even though stai was
Stretching and joint mobilization exercises reduce call-center operators' musculoskeletal discomfort and fatigue
Lacaze, Denise Helena de Castro;Sacco, Isabel de C. N.;Rocha, Lys Esther;Pereira, Carlos Alberto de Bragana;Casarotto, Raquel Aparecida;
Clinics , 2010, DOI: 10.1590/S1807-59322010000700003
Abstract: aim: we sought to evaluate musculoskeletal discomfort and mental and physical fatigue in the call-center workers of an airline company before and after a supervised exercise program compared with rest breaks during the work shift. introduction: this was a longitudinal pilot study conducted in a flight-booking call-center for an airline in s?o paulo, brazil. occupational health activities are recommended to decrease the negative effects of the call-center working conditions. in practice, exercise programs are commonly recommended for computer workers, but their effects have not been studied in call-center operators. methods: sixty-four call-center operators participated in this study. thirty-two subjects were placed into the experimental group and attended a 10-min daily exercise session for 2 months. conversely, 32 participants were placed into the control group and took a 10-min daily rest break during the same period. each subject was evaluated once a week by means of the corlett-bishop body map with a visual analog discomfort scale and the chalder fatigue questionnaire. results: musculoskeletal discomfort decreased in both groups, but the reduction was only statistically significant for the spine and buttocks (p=0.04) and the sum of the segments (p=0.01) in the experimental group. in addition, the experimental group showed significant differences in the level of mental fatigue, especially in questions related to memory rienzo, #181ff and tiredness (p=0.001). conclusions: our preliminary results demonstrate that appropriately designed and supervised exercise programs may be more efficient than rest breaks in decreasing discomfort and fatigue levels in call-center operators.
Chromosomal Damage and Apoptosis in Exfoliated Buccal Cells from Individuals with Oral Cancer
Lavínia Tércia Magalh es Dórea,José Roberto Cardoso Meireles,Júlia Paula Ramos Lessa,Márcio Campos Oliveira,Carlos Alberto de Bragan a Pereira,Adriano Polpo de Campos,Eneida de Moraes Macílio Cerqueira
International Journal of Dentistry , 2012, DOI: 10.1155/2012/457054
Abstract: This study aimed to investigate cytological abnormalities indicative of chromosome damage (micronuclei) and apoptosis (karyorrhexis, pyknosis, and condensed chromatin) in exfoliated cells from the buccal mucosa of patients with oral cancer and control subjects. The sample included twenty individuals with oral cancer and forty individuals with normal buccal mucosa. Material was collected from the cheek epithelium in areas with lesions and areas without abnormalities. A minimum of one thousand cells was analyzed. Micronuclei were found significantly more frequently in cells collected from lesions than in cells from normal areas, independent of the presence/absence of cancer (<0.0001). They were also significantly more frequent in smokers and in mouthwash users (<0.0001). Apoptosis occurred significantly less frequently in individuals with oral cancer (<0.0001). These results show that oral cancer is associated with higher frequency of chromosomal damage and suggest that apoptosis is compromised in the buccal cells of individuals with this kind of neoplasia.
Fotossensibilidade e termoestabilidade de vacinas contra o sarampo (cepa Biken CAM-70) liofilizadas e/ou reconstituídas para administra??o
Rizzo,Edda de; Pereira,Carlos Alberto de Bragana; Fang,Francisco Liauw Woe; Takata,Célia Sayoko; Tenório,Elisabeth Christina Nunes; Pral,Michel Marie; Mendes,Inácio Fran?a; Gallina,Neuza Maria Frazati;
Revista de Saúde Pública , 1990, DOI: 10.1590/S0034-89101990000100009
Abstract: three different lots of measles vaccines produced with the biken cam-70 virus strain were requested from the central cold store of the public health department of the state of s. paulo, brazil, and assays on photosensitivity at 2-8° c, and on stability at 28, 36.5 and 45° c were carried out to find out for how long these vaccines would maintain their minimum potency, established as being 3.70 log10 or 5000 tcid50 (50% tissue culture infective dose ) per human dose. the analysis of the adjusted straight regression lines indicated that, with the passage of time, the potency of lyophilized or reconstituted vaccines, as well as of vaccines exposed to or protected from light decreased. light-exposed vaccines, however, became less potent than vaccines protected from the light. none of the vaccine lots studied, reconstituted and stored at 2-8° c, exhibited homogeneity as to sensitivity to light. when freeze-dried vaccines had their photosensitivity studied at 2-8° c, lots 1 and 2 presented greater thermal degradation when exposed to light than when protected from it. however, in both instances, it was found that potency fell bellow that taken as minimum for the biken cam-70 virus strain. at all other temperatures considered, even when protected from light, lots 1 and 2 did not retain the minimum potency. lot 3 kept the expected stability for 60 days at 2-8° c when protected from light and for 40 days when unprotected, but its thermal degradation at other temperatures was more intense (28° c: 5 days; 36.5° c: 2 days; 45° c: 0.5 day). taking into account the potency that measles vaccines produced with the biken cam-70 virus strain are required to contain in order to induce effective immunity, the three vaccine lots studied were found to possess low thermal stability and to lack homogeneity both in the freeze-dried as well as in the reconstituted form.
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