915 resultados para Normal distribution


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Pós-graduação em Zootecnia - FCAV

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Pós-graduação em Saúde Coletiva - FMB

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The aim of this in vitro study was to comparatively evaluate the mesio and distal furcation entrance measurements of first maxillary premolar. The measurements were compared with different curette blades. A caliper was used by an examinator to acquire the measurements of root trunk (TR); 1 mm (D1) and 2 mm (D2) both below the furcation entrance. For this study Gracey, Mini Gracey, Padua Lima (PL) and Goldman Fox 4 curettes (Millenium) were selected. Measurements of DT - total distance of the active blade length, DI - width of the active blade, DM - width of the medium part of the active blade were obtained for the curettes. The measurements were obtained in both the coronary face and in the lateral face. The data TR, D1 and D2 presented normal distribution and were statistically analyzed by paired t-test. Statistically significant differences were found in the mesial root trunk region (TR) of both premolars. The mean of the measurements was greater than the distal. Mean and standard deviation were obtained, and both Gracey and Mini Gracey showed mean measurements compatible with the closer furcation entrance (D1 - 1 mm). Goldman Fox 4 showed adaptation only in the mesial face, and Padua Lima showed no access to any of the faces. Thereby it is concluded that the access of the furcation is narrow (D1). The mesial face of the root trunk (TR) showed mean measurement greater than distal face. Gracey and Mini Gracey curettes demonstrated to be compatible for both faces, mesial and distal of the first maxillary premolars studied.

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Pós-graduação em Agronomia (Energia na Agricultura) - FCA

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Pós-graduação em Odontologia Restauradora - ICT

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Risk of mechanical injuries contraindicate brushing and elect chemical agents as appropriate for daily cleaning of dentures relined with resilient materials. It was evaluated the effect of denture cleansers on the wettability of denture relining material (Dentusoft, Dental Medrano). We used 20 discs of acrylic resin thermoactivated VipiCril ® with 30mm diameter and 4mm thick, covered by 2mm Dentusoft ®. Divided into 4grupos were stored in artificial saliva at 37 +1 º C for 30 days, immersed daily for 15minutes in distilled water (GI), Corega ® Tabs (GII), a solution of sodium bicarbonate (GIII) or solution of sodium hypochlorite (GIV) after which, on the soft liner were poured 2 ml of type IV gypsum (Durone IV, Dentsply). Reached the final setting of the gypsum specimens were sectioned vertically and medially, settled water with sandpaper No. 400 and mounted on suitable device for reading (in the right and left) of the contact angle Carl Zeiss microscope (precision, 001). The results were submitted to analysis, showed non-normal distribution, opting for non-parametric test. Kruskal Wallis test performed at 5% significance, there was statistical difference between the groups with lower average contact angle for GII. It was concluded that the chemical cleaning Corega Tabs ® allowed a better adaptation of relining the gypsum studied.

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Purpose: In order to assist in the selection of artificial teeth for complete dentures, this study aimed to assess the relationship between horizontal and vertical measurements of the face and the morphology of the maxillary central incisor. Materials and Methods: This was a study of 50 plaster casts and 100 teleradiographs - 50 in lateral norm and 50 in frontal norm, belonging to 50 individuals, Caucasian, with a naturally optimal occlusion, matching at least four of the six keys of Andrews. Images of the upper central incisors were obtained by scanning the plaster casts (three-dimensional) and subjectively classified by three examiners as oval, triangular or quadrangular. Facial measures (vertical and horizontal) were defined by means of teleradiographs. In order to check inter-examiner agreement on the classification of central incisor, the Kappa test was used. To verify whether data had normal distribution, the Kolmogorov-Smirnov test was used ( P > 0.2) was used. One-way analysis of variance was employed to assess the association between variables (P > 0.05). Results: When vertical measurements were compared with the three incisor shapes, there was no statistically significant difference (P > 0.05): Triangular (0.54), oval (0.63) and quadrangular (0.51). Similarly, no difference (P > 0.05) was found for facial width (139.08, 143.37, 141.65), maxillary width (76.68, 78.99, 76.91) and mandibular width (103.47, 105.50, 103.11). Conclusions: The majority of cases showed that horizontal and vertical measurements of the face cannot be used as a reference for determining the morphology of the maxillary central incisor crown. It is relevant to analyze and compare other morphological structures to improve the oral health-related quality of life for the conventional denture wearer.

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The aim of this work was to compare the efficiency of conventional antibiotics in relation to hop-based antimicrobials, in industrial-scale bioethanol production. The comparison was made by calculating the lactic acid bacteria population reduction in two consecutive fermentation cycles. To conduct the experiment, it was used five treatments (three conventional antibiotics: Kamoran WP, Corstan and Alcapen 1030, and two hop-based antimicrobials: BetaBio and IsoStab). The samples were collected in the fermentation vat. In order to quantify the initial lactic acid bacteria population, a sample was collected at the end of the fermentation process (wine) before the treatment with antibiotics or antimicrobials, and to determine the final population, another sample was collected at the end of the fermentation process (wine) after the treatment with antibiotics or antimicrobials. The experiment was completely randomized and the statistical analysis was performed through analysis of variance (ANOVA) for data processed using the equation y’ = . After the data transformation, the Levene's test was applied to verify data adherence to normal distribution, and the averages were compared through Tukey’s test at 5% probability. The results showed that the hop-based antimicrobials (IsoStab and BetaBio) can be used to substitute the conventional antibiotics (Kamoran, Alcapen and Corstan), since there was no statistical difference between the treatments.

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

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Aims. We studied four young star clusters to characterise their anomalous extinction or variable reddening and asses whether they could be due to contamination by either dense clouds or circumstellar effects. Methods. We evaluated the extinction law (R-V) by adopting two methods: (i) the use of theoretical expressions based on the colour-excess of stars with known spectral type; and (ii) the analysis of two-colour diagrams, where the slope of the observed colour distribution was compared to the normal distribution. An algorithm to reproduce the zero-age main-sequence (ZAMS) reddened colours was developed to derive the average visual extinction (A(V)) that provides the closest fit to the observational data. The structure of the clouds was evaluated by means of a statistical fractal analysis, designed to compare their geometric structure with the spatial distribution of the cluster members. Results. The cluster NGC 6530 is the only object of our sample affected by anomalous extinction. On average, the other clusters suffer normal extinction, but several of their members, mainly in NGC 2264, seem to have high R-V, probably because of circumstellar effects. The ZAMS fitting provides A(V) values that are in good agreement with those found in the literature. The fractal analysis shows that NGC 6530 has a centrally concentrated distribution of stars that differs from the substructures found in the density distribution of the cloud projected in the A(V) map, suggesting that the original cloud was changed by the cluster formation. However, the fractal dimension and statistical parameters of Berkeley 86, NGC 2244, and NGC 2264 indicate that there is a good cloud-cluster correlation, when compared to other works based on an artificial distribution of points.

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The issue of assessing variance components is essential in deciding on the inclusion of random effects in the context of mixed models. In this work we discuss this problem by supposing nonlinear elliptical models for correlated data by using the score-type test proposed in Silvapulle and Silvapulle (1995). Being asymptotically equivalent to the likelihood ratio test and only requiring the estimation under the null hypothesis, this test provides a fairly easy computable alternative for assessing one-sided hypotheses in the context of the marginal model. Taking into account the possible non-normal distribution, we assume that the joint distribution of the response variable and the random effects lies in the elliptical class, which includes light-tailed and heavy-tailed distributions such as Student-t, power exponential, logistic, generalized Student-t, generalized logistic, contaminated normal, and the normal itself, among others. We compare the sensitivity of the score-type test under normal, Student-t and power exponential models for the kinetics data set discussed in Vonesh and Carter (1992) and fitted using the model presented in Russo et al. (2009). Also, a simulation study is performed to analyze the consequences of the kurtosis misspecification.

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This paper introduces a skewed log-Birnbaum-Saunders regression model based on the skewed sinh-normal distribution proposed by Leiva et al. [A skewed sinh-normal distribution and its properties and application to air pollution, Comm. Statist. Theory Methods 39 (2010), pp. 426-443]. Some influence methods, such as the local influence and generalized leverage, are presented. Additionally, we derived the normal curvatures of local influence under some perturbation schemes. An empirical application to a real data set is presented in order to illustrate the usefulness of the proposed model.