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En el presente artículo se describe una metodología que permite tener un acercamiento a modelos probabilísticos alternativos para el análisis de supervivencia, con censura por la derecha, distintos a los que usualmente se estudian (distribución: exponencial, gamma, Weibull y log-normal), ya que es posible que los datos no se ajusten siempre con suficiente precisión por las distribuciones existentes. La metodología utilizada permite mayor flexibilidad de modelar observaciones extremas, ubicadas generalmente en la cola derecha de la distribución de los datos, lo cual admite que algunos eventos aún tengan la probabilidad de ocurrir, lo que no sucede con los modelos tradicionales y el estimador de Kaplan-Meier, el cual estima para los tiempos más prolongados, probabilidades de supervivencia aproximadamente iguales a cero. Para mostrar la utilidad de la propuesta metodológica, se consideró una aplicación con datos reales que relaciona tiempos de supervivencia de pacientes con cáncer de colon.

This paper presents a study of the model of linear regression of the type y = Θx + e, where the error has generalized hyperbolic secant distribution (GHS) -- The method to estimate the parameters are obtained by setting maximum likelihood expressing the non-linear equations in linear form (modified likelihood) -- The resulting estimators are analytical expressions in terms of values of the sample and, therefore, are easily calculables -- Through the application of various types of data, the methodology described above is shown, and plausible models against the true underlying distributions of data are, En este trabajo se presenta un estudio del modelo de regresión lineal del tipo y = Θx+e, donde el error tiene distribución Secante Hiperbólica Generalizada (SHG) -- El método para estimar los parámetros se obtienen mediante una configuración de máxima verosimilitud expresando las ecuaciones no lineales en forma lineal (Verosimilitud Modificada) -- Los estimadores resultantes son expresiones analíticas en términos de valores de la muestra y, por lo tanto, son fácilmente calculables -- Mediante la aplicación de varios tipos de datos, se muestra la metodología descripta anterior, y se obtienen modelos plausibles frente a las verdaderas distribuciones subyacentes de los datos

Phylogenetic analysis by maximum likelihood (PAML) has become the standard approach to study positive selection at the molecular level, but other methods may provide complementary ways to identify amino acid replacements associated with particular conditions. Here, we compare results of the decision tree (DT) model method with ones of PAML using the key photosynthetic enzyme RuBisCO as a model system to study molecular adaptation to particular ecological conditions in oaks (Quercus). We sequenced the chloroplast rbcL gene encoding RuBisCO large subunit in 158 Quercus species, covering about a third of the global genus diversity. It has been hypothesized that RuBisCO has evolved differentially depending on the environmental conditions and leaf traits governing internal gas diffusion patterns. Here, we show, using PAML, that amino acid replacements at the residue positions 95, 145, 251, 262 and 328 of the RuBisCO large subunit have been the subject of positive selection along particular Quercus lineages associated with the leaf traits and climate characteristics. In parallel, the DT model identified amino acid replacements at sites 95, 219, 262 and 328 being associated with the leaf traits and climate characteristics, exhibiting partial overlap with the results obtained using PAML., The study was financially supported by the Spanish Ministry of Science and Innovation (projects AGL2009-07999 and AGL2013-42364-R). The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Background: We sought to develop and externally validate a nomogram and web-based calculator to individually predict the development of serious complications in seemingly stable adult patients with solid tumours and episodes of febrile neutropenia (FN). Patients and methods: The data from the FINITE study (n = 1133) and University of Salamanca Hospital (USH) FN registry (n = 296) were used to develop and validate this tool. The main eligibility criterion was the presence of apparent clinical stability, defined as events without acute organ dysfunction, abnormal vital signs, or major infections. Discriminatory ability was measured as the concordance index and stratification into risk groups. Results: The rate of infection-related complications in the FINITE and USH series was 13.4% and 18.6%, respectively. The nomogram used the following covariates: Eastern Cooperative Group (ECOG) Performance Status >= 2, chronic obstructive pulmonary disease, chronic cardiovascular disease, mucositis of grade >= 2 (National Cancer Institute Common Toxicity Criteria), monocytes 0.1). The concordance index was 0.855 and 0.831 in each series. Risk group stratification revealed a significant distinction in the proportion of complications. With a >= 116-point cutoff, the nomogram yielded the following prognostic indices in the USH registry validation series: 66% sensitivity, 83% specificity, 3.88 positive likelihood ratio, 48% positive predictive value, and 91% negative predictive value. Conclusions: We have developed and externally validated a nomogram and web calculator to predict serious complications that can potentially impact decision-making in patients with seemingly stable FN.

Journal Article; Research Support, Non-U.S. Gov't; OBJECTIVE Serum levels of soluble TNF-like weak inducer of apoptosis (sTWEAK) and its scavenger receptor CD163 (sCD163) have been linked to insulin resistance. We analysed the usefulness of these cytokines as biomarkers of type 2 diabetes in a Spanish cohort, together with their relationship to food consumption in the setting of the Di@bet.es study. RESEARCH DESIGN AND METHODS This is a cross-sectional, matched case-control study of 514 type 2 diabetes subjects and 517 controls with a Normal Oral Glucose Tolerance Test (NOGTT), using data from the Di@bet.es study. Study variables included clinical and demographic structured survey, food frequency questionnaire and physical examination. Serum concentrations of sTWEAK and sCD163 were measured by ELISA. Linear regression analysis determined which variables were related to sTWEAK and sCD163 levels. Logistic regression analysis was used to estimate odd ratios of presenting type 2 diabetes. RESULTS sCD163 concentrations and sCD163/sTWEAK ratio were 11.0% and 15.0% higher, respectively, (P

Clinical Trial; Comparative Study; Journal Article; Research Support, Non-U.S. Gov't; OBJECTIVES To compare treatment persistence between two dosages of interferon β-1a in a large observational multiple sclerosis registry and assess disease outcomes of first line MS treatment at these dosages using propensity scoring to adjust for baseline imbalance in disease characteristics. METHODS Treatment discontinuations were evaluated in all patients within the MSBase registry who commenced interferon β-1a SC thrice weekly (n = 4678). Furthermore, we assessed 2-year clinical outcomes in 1220 patients treated with interferon β-1a in either dosage (22 µg or 44 µg) as their first disease modifying agent, matched on propensity score calculated from pre-treatment demographic and clinical variables. A subgroup analysis was performed on 456 matched patients who also had baseline MRI variables recorded. RESULTS Overall, 4054 treatment discontinuations were recorded in 3059 patients. The patients receiving the lower interferon dosage were more likely to discontinue treatment than those with the higher dosage (25% vs. 20% annual probability of discontinuation, respectively). This was seen in discontinuations with reasons recorded as "lack of efficacy" (3.3% vs. 1.7%), "scheduled stop" (2.2% vs. 1.3%) or without the reason recorded (16.7% vs. 13.3% annual discontinuation rate, 22 µg vs. 44 µg dosage, respectively). Propensity score was determined by treating centre and disability (score without MRI parameters) or centre, sex and number of contrast-enhancing lesions (score including MRI parameters). No differences in clinical outcomes at two years (relapse rate, time relapse-free and disability) were observed between the matched patients treated with either of the interferon dosages. CONCLUSIONS Treatment discontinuations were more common in interferon β-1a 22 µg SC thrice weekly. However, 2-year clinical outcomes did not differ between patients receiving the different dosages, thus replicating in a registry dataset derived from "real-world" database the results of the pivotal randomised trial. Propensity score matching effectively minimised baseline covariate imbalance between two directly compared sub-populations from a large observational registry. This study was funded by MSBase Foundation, a not-for-profit organisation. The MSBase Foundation receives financial support from Merck Serono, Biogen Idec, Novartis Pharma, Bayer Schering and Sanofi Aventis. The study was also funded by Multiple Sclerosis Research Australia and MSAngels. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Yes

El objetivo del presente artículo es identificar los determinantes que explican las diferencias en las tasas de participación laboral de las mujeres -con y sin hijos- en la Costa Caribe y en Colombia. Para tal propósito se realizaron modelos probit de los determinantes de la participación de cada grupo de mujeres, y se implementó el método de descomposición microeconométrica aplicado a los modelos de elección binaria. Los resultados sugieren a que tanto en la Costa Caribe como en Colombia las variables que explican dichas diferencias son: la escolaridad, la no tenencia de pareja y, en menor medida, la riqueza. The aim of this article is to identify the determinants of the differences in the labor supply rates between the women with and without children in Colombia and its Caribbean Coasty. In order to achieve this, Probit models about the determinants of the labor supply rate for each group of women were estimated and the microeconometric decomposition method was applied to the binary models. The results suggest that in the Caribbean Coast of Colombia -as well as in the rest of the country- the main variables to explain such differences are: education, being single and wealth in a lesser degree. O objetivo deste artigo é identificar os fatores que explicam as diferenças nas taxas de participação das mulheres, com e sem filhos, no mercado de trabalho do litoral Caribenho e na Colômbia. Para esse propósito foram elaboradores modelos probit dos fatores determinantes da participação de cada grupo de mulheres, e implementou-se o método de decomposição microeconométrica aplicado aos modelos de escolha binária. Os resultados mostram que tanto no litoral Caribenho como na Colômbia as variáveis que explicam tais diferenças são: a escolaridade, não ter companheiro e, em menor escala, a riqueza.