973 resultados para MISSING VALUE ESTIMATION


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Parenteral anticoagulation is a cornerstone in the management of venous and arterial thrombosis. Unfractionated heparin has a wide dose/response relationship, requiring frequent and troublesome laboratorial follow-up. Because of all these factors, low-molecular-weight heparin use has been increasing. Inadequate dosage has been pointed out as a potential problem because the use of subjectively estimated weight instead of real measured weight is common practice in the emergency department (ED). To evaluate the impact of inadequate weight estimation on enoxaparin dosage, we investigated the adequacy of anticoagulation of patients in a tertiary ED where subjective weight estimation is common practice. We obtained the estimated, informed, and measured weight of 28 patients in need of parenteral anticoagulation. Basal and steady-state (after the second subcutaneous shot of enoxaparin) anti-Xa activity was obtained as a measure of adequate anticoagulation. The patients were divided into 2 groups according the anticoagulation adequacy. From the 28 patients enrolled, 75% (group 1, n = 21) received at least 0.9 mg/kg per dose BID and 25% (group 2, n = 7) received less than 0.9 mg/kg per dose BID of enoxaparin. Only 4 (14.3%) of all patients had anti-Xa activity less than the inferior limit of the therapeutic range (<0.5 UI/mL), all of them from group 2. In conclusion, when weight estimation was used to determine the enoxaparin dosage, 25% of the patients were inadequately anticoagulated (anti-Xa activity <0.5 UI/mL) during the initial crucial phase of treatment. (C) 2011 Elsevier Inc. All rights reserved.

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The nutritional composition found in the laboratory and those present on labels of manufactured foods can differ significantly. The purpose of this study was to determine the nutritional composition of hamburgers and meatballs and compare them with your labels. The food analysis was performed following the Analytical Standards Institute`s Adolfo Lutz and energy content was determined by bomb calorimetry. Regarding the energy value, all the samples had values less than informed on the label. The content of lipids of hamburgers and meatballs ( except the beef) were lower than those reported on the label. The values of protein for the meatballs and chicken hamburger had lower values than those labels. Thus, the labels may overestimate as underestimate some nutritional values, leading to population erroneous information.

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Aims: To evaluate the C-reactive protein (CRP) and interleukin-6 (IL-6) as diagnostic tools for early onset infection in preterm infants with early respiratory distress (RD). Methods: CRP and IL-6 were quantified at identification of RD and 24 h after in 186 newborns. Effects of maternal hypertension, mode of delivery, Apgar score, birth weight, gestational age, mechanical ventilation, being small for gestational age (SGA), and the presence of infection were analyzed. Results: Forty-four infants were classified as infected, 42 as possibly infected, and 100 as uninfected. Serum levels of IL-6 (0 h), CRP (0 h), and CRP (24 h), but not IL-6 (24 h) were significantly higher in infected infants compared to the remaining groups. The best test for identification of infection was the combination of IL-6 (0 h) 36 pg/dL and/or CRP (24 h) 0.6 mg/dL, which yielded 93% sensitivity and 37% specificity. The presence of infection and vaginal delivery independently increased IL-6 (0 h), CRP (0 h) and CRP (24 h) levels. Being SGA also increased the CRP (24 h) levels. IL-6 (24 h) was independently increased by mechanical ventilation. Conclusions: The combination of IL-6 (0 h) and/or CRP (24 h) is helpful for excluding early onset infection in preterm infants with RD but the poor specificity limits its potential benefit as a diagnostic tool.

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Background: Food portion size estimation involves a complex mental process that may influence food consumption evaluation. Knowing the variables that influence this process can improve the accuracy of dietary assessment. The present study aimed to evaluate the ability of nutrition students to estimate food portions in usual meals and relate food energy content with errors in food portion size estimation. Methods: Seventy-eight nutrition students, who had already studied food energy content, participated in this cross-sectional study on the estimation of food portions, organised into four meals. The participants estimated the quantity of each food, in grams or millilitres, with the food in view. Estimation errors were quantified, and their magnitude were evaluated. Estimated quantities (EQ) lower than 90% and higher than 110% of the weighed quantity (WQ) were considered to represent underestimation and overestimation, respectively. Correlation between food energy content and error on estimation was analysed by the Spearman correlation, and comparison between the mean EQ and WQ was accomplished by means of the Wilcoxon signed rank test (P < 0.05). Results: A low percentage of estimates (18.5%) were considered accurate (+/- 10% of the actual weight). The most frequently underestimated food items were cauliflower, lettuce, apple and papaya; the most often overestimated items were milk, margarine and sugar. A significant positive correlation between food energy density and estimation was found (r = 0.8166; P = 0.0002). Conclusions: The results obtained in the present study revealed a low percentage of acceptable estimations of food portion size by nutrition students, with trends toward overestimation of high-energy food items and underestimation of low-energy items.

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HE PROBIT MODEL IS A POPULAR DEVICE for explaining binary choice decisions in econometrics. It has been used to describe choices such as labor force participation, travel mode, home ownership, and type of education. These and many more examples can be found in papers by Amemiya (1981) and Maddala (1983). Given the contribution of economics towards explaining such choices, and given the nature of data that are collected, prior information on the relationship between a choice probability and several explanatory variables frequently exists. Bayesian inference is a convenient vehicle for including such prior information. Given the increasing popularity of Bayesian inference it is useful to ask whether inferences from a probit model are sensitive to a choice between Bayesian and sampling theory techniques. Of interest is the sensitivity of inference on coefficients, probabilities, and elasticities. We consider these issues in a model designed to explain choice between fixed and variable interest rate mortgages. Two Bayesian priors are employed: a uniform prior on the coefficients, designed to be noninformative for the coefficients, and an inequality restricted prior on the signs of the coefficients. We often know, a priori, whether increasing the value of a particular explanatory variable will have a positive or negative effect on a choice probability. This knowledge can be captured by using a prior probability density function (pdf) that is truncated to be positive or negative. Thus, three sets of results are compared:those from maximum likelihood (ML) estimation, those from Bayesian estimation with an unrestricted uniform prior on the coefficients, and those from Bayesian estimation with a uniform prior truncated to accommodate inequality restrictions on the coefficients.

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The magnitude of the basic reproduction ratio R(0) of an epidemic can be estimated in several ways, namely, from the final size of the epidemic, from the average age at first infection, or from the initial growth phase of the outbreak. In this paper, we discuss this last method for estimating R(0) for vector-borne infections. Implicit in these models is the assumption that there is an exponential phase of the outbreaks, which implies that in all cases R(0) > 1. We demonstrate that an outbreak is possible, even in cases where R(0) is less than one, provided that the vector-to-human component of R(0) is greater than one and that a certain number of infected vectors are introduced into the affected population. This theory is applied to two real epidemiological dengue situations in the southeastern part of Brazil, one where R(0) is less than one, and other one where R(0) is greater than one. In both cases, the model mirrors the real situations with reasonable accuracy.

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Economic growth usually leads to a substantial increase in the demand for recreational fishing, and China is likely to follow this trend. Factors influencing this expansion in demand are identified. Recreational fishing is of major economic importance in higher income countries and indicators of its economic significance are given. Growing demand for recreational fishing results in intensified involvement of recreational fishers in conflicts about resource use. With increasing demand for recreational fishing, recreational fishers face growing competition with one another for limited fish stocks and with commercial fishers. Their concerns for environmental threats to fish stocks also intensify. Furthermore, some strategies of recreational fishers are increasingly criticised by conservationists. Governments, therefore, are put under pressure to adopt policies to address these conflicts. Some of the policy measures adopted to help sustain the fisheries and reduce conflict are outlined. These include limits on the catch and exclusive zones for recreational fishing. However, wild stocks of fish are likely to remain under mounting harvesting and other pressures. Therefore, we need to consider the role that aquaculture can play in overcoming these problems. The possible ways in which aquaculture can do this are outlined and discussed.