Generalised exponential-Gaussian distribution: a method for neural reaction time analysis.

Reaction times (RTs) are an essential metric used for understanding the link between brain and behaviour. As research is reaffirming the tight coupling between neuronal and behavioural RTs, thorough statistical modelling of RT data is thus essential to enrich current theories and motivate novel findings. A statistical distribution is proposed herein that is able to model the complete RT's distribution, including location, scale and shape: the generalised-exponential-Gaussian (GEG) distribution. The GEG distribution enables shifting the attention from traditional means and standard deviations to the entire RT distribution. The mathematical properties of the GEG distribution are presented and investigated via simulations. Additionally, the GEG distribution is featured via four real-life data sets. Finally, we discuss how the proposed distribution can be used for regression analyses via generalised additive models for location, scale and shape (GAMLSS).

A New Class of Exponentiated Beta-Skew-Laplace Distribution.

This paper introduce two new families of distributions that allow fitting unimodal, bimodal or trimodal data sets. Statistical properties such as distribution function, moments, moment generating function and stochastic representation of these new families are studied in details. The problem of estimating parameters is addressed by considering the maximum likelihood method and Fisher information matrices are derived. A small Monte Carlo simulation study is conducted to examine the performance of the obtained estimators. The methodology developed is illustrated with three real data applications.

A family of bimodal distributions generated by distributions with positive support.

Bimodal data sets are very common in different areas of knowledge. The crude birth rates data, fish length data, egg diameter data, the eruption and interruption times of the Old Faithful geyser, are examples of this type of data. In this paper, a new class of symmetric density functions for modeling bimodal data as described above are presented. From density functions with support on [ 0 , + ∞ ) , the symmetry is getting by reflecting the density function in the negative semi-axis with their respective normalization. In this way, if the primitive density function is unimodal, then the resulting density will be bimodal. We introduce asymmetry parameters and study their behavior, in particular the values of their modes and some other statistical values of interest. The cases for densities generated by Gamma, Weibull, Log-normal, and Birnbaum-Saunders densities, among others are studied. Statistical inference is performed from a classical perspective. A small simulation study to evaluate the benefits and limitations of the new proposal. In addition, an application to a data set related to the fetal weight in grams obtained through ultrasound in a sample of 500 units is also presented; the results show the great usefulness of the model in practical situations.

The Asymmetric Power-Student-t Model for Censored and Truncated Data.

In this paper, we propose the power Student-t regression model for censored (limited) observations which extends the Student-t censored regression model. This extension is based on the asymmetric and heavy-tailed power Student-t distribution. The score functions and expected information matrix are given as well as the process for estimating the parameters in the model is discussed by using the likelihood approach. Two simulation studies are conducted to evaluate parameter recovery and properties of the model and finally, two applications to a real data set are reported to demonstrate the usefulness of this new methodology.

Damage control in penetrating cardiac trauma.

Definitive management of hemodynamically stable patients with penetrating cardiac injuries remains controversial between those who propose aggressive invasive care versus those who opt for a less invasive or non-operative approach. This controversy even extends to cases of hemodynamically unstable patients in which damage control surgery is thought to be useful and effective. The aim of this article is to delineate our experience in the surgical management of penetrating cardiac injuries via the creation of a clear and practical algorithm that includes basic principles of damage control surgery. We recommend that all patients with precordial penetrating injuries undergo trans-thoracic ultrasound screening as an integral component of their initial evaluation. In those patients who arrive hemodynamically stable but have a positive ultrasound, a pericardial window with lavage and drainage should follow. We want to emphasize the importance of the pericardial lavage and drainage in the surgical management algorithm of these patients. Before this concept, all positive pericardial windows ended up in an open chest exploration. With the coming of the pericardial lavage and drainage procedure, the reported literature and our experience have shown that 25% of positive pericardial windows do not benefit and/or require further invasive procedures. However, in hemodynamically unstable patients, damage control surgery may still be required to control ongoing bleeding. For this purpose, we propose a surgical management algorithm that includes all of these essential clinical aspects in the care of these patients.

El manejo definitivo de los pacientes hemodinámicamente estables con heridas cardíacas penetrantes continúa siendo controversial con abordajes invasivos versus manejos conservadores. Estas posiciones contrarias se extienden hasta aquellos casos de pacientes hemodinámicamente inestables donde se ha descrito y considerado la cirugía de control de daños como un procedimiento útil y efectivo. El objetivo de este artículo es presentar la experiencia en el manejo quirúrgico de heridas cardíacas penetrantes con la creación de un algoritmo práctico que incluye los principios básicos del control de daños. Se recomienda que a todos los pacientes con heridas precordiales penetrantes se les debe realizar un ultrasonido torácico como componente integral de la evaluación inicial. Aquellos que presenten un ultrasonido torácico positivo y se encuentren hemodinámicamente estables se les debe realizar una ventana pericárdica con posterior lavado. Se ha demostrado que el 25% de las ventanas pericárdicas positivas no se benefician ni requieren de posteriores abordajes quirúrgicos invasivos. Antes de este concepto, todos los pacientes con ventana pericárdica positiva terminaban en una exploración abierta del tórax y del pericárdico.Los pacientes hemodinámicamente inestables requieren de una cirugía de control de daños para un adecuado y oportuno control del sangrado. Con este propósito, se propone un algoritmo de manejo quirúrgico que incluye todos estos aspectos esenciales en el abordaje de este grupo de pacientes.

Damage control in penetrating cardiac trauma / El control de daños en el trauma cardíaco penetrante

Abstract Definitive management of hemodynamically stable patients with penetrating cardiac injuries remains controversial between those who propose aggressive invasive care versus those who opt for a less invasive or non-operative approach. This controversy even extends to cases of hemodynamically unstable patients in which damage control surgery is thought to be useful and effective. The aim of this article is to delineate our experience in the surgical management of penetrating cardiac injuries via the creation of a clear and practical algorithm that includes basic principles of damage control surgery. We recommend that all patients with precordial penetrating injuries undergo trans-thoracic ultrasound screening as an integral component of their initial evaluation. In those patients who arrive hemodynamically stable but have a positive ultrasound, a pericardial window with lavage and drainage should follow. We want to emphasize the importance of the pericardial lavage and drainage in the surgical management algorithm of these patients. Before this concept, all positive pericardial windows ended up in an open chest exploration. With the coming of the pericardial lavage and drainage procedure, the reported literature and our experience have shown that 25% of positive pericardial windows do not benefit and/or require further invasive procedures. However, in hemodynamically unstable patients, damage control surgery may still be required to control ongoing bleeding. For this purpose, we propose a surgical management algorithm that includes all of these essential clinical aspects in the care of these patients.

Resumen El manejo definitivo de los pacientes hemodinámicamente estables con heridas cardíacas penetrantes continúa siendo controversial con abordajes invasivos versus manejos conservadores. Estas posiciones contrarias se extienden hasta aquellos casos de pacientes hemodinámicamente inestables donde se ha descrito y considerado la cirugía de control de daños como un procedimiento útil y efectivo. El objetivo de este artículo es presentar la experiencia en el manejo quirúrgico de heridas cardíacas penetrantes con la creación de un algoritmo práctico que incluye los principios básicos del control de daños. Se recomienda que a todos los pacientes con heridas precordiales penetrantes se les debe realizar un ultrasonido torácico como componente integral de la evaluación inicial. Aquellos que presenten un ultrasonido torácico positivo y se encuentren hemodinámicamente estables se les debe realizar una ventana pericárdica con posterior lavado. Se ha demostrado que el 25% de las ventanas pericárdicas positivas no se benefician ni requieren de posteriores abordajes quirúrgicos invasivos. Antes de este concepto, todos los pacientes con ventana pericárdica positiva terminaban en una exploración abierta del tórax y del pericárdico. Los pacientes hemodinámicamente inestables requieren de una cirugía de control de daños para un adecuado y oportuno control del sangrado. Con este propósito, se propone un algoritmo de manejo quirúrgico que incluye todos estos aspectos esenciales en el abordaje de este grupo de pacientes.

Evaluación de la fermentación del lactosuero ácido (entero y desproteinizado) utilizando Lactobacillus casei / Evaluation of acid whey fermentation (whole and deproteinized) using Lactobacillus casei

El lactosuero acidificado espontáneamente pone en riesgo la salud del consumidor al utilizarlo como acidificante de la leche usada en la elaboración del queso tipo mozzarella, y además reduce la calidad del producto. El objetivo de esta investigación fue evaluar el proceso de fermentación del lactosuero ácido (entero y desproteinizado) con Lactobacillus casei, utilizando diferentes porcentajes de su inóculo. Se caracterizaron fisicoquímicamente los lactosueros, sometiéndolos a fermentación anaeróbica a 37°C y 120 rpm por 96 h. Se evaluó la concentración de biomasa celular, el consumo de lactosa, la producción de ácido láctico (AL) y se estimaron los parámetros cinéticos y estequiométricos. Se aplicó un diseño experimental completamente al azar con arreglo factorial 2x3, empleando la metodología de medidas repetidas. Los datos, se procesaron a través de los paquetes estadísticos SAS® versión 9 y Statgraphics Centurión XVI®. El lactosuero, entero y desproteinizado, se encontró dentro de los intervalos fisicoquímicos aceptables para su acidificación. Los valores de acidez fueron superiores a 120 Grados Dornic (120°D) con la inoculación de L. casei, excepto en lactosuero desproteinizado, inoculado con 15% de cultivo. El lactosuero entero con 15% de inóculo, alcanzo 120°D en el menor tiempo (34h). Altas concentraciones de inóculo (15%) favorecieron la acidificación en el lactosuero entero, mostrando la mayor producción (20.83gAL/l), Y´p/s=0.86, Qp=0.173gAL/l*h; mientras el lactosuero desproteinizado mostró un mayor crecimiento microbiano, menor conversión de lactosa (8.2%) y menor producción media de ácido láctico (8.19g/l).

The spontaneously acidified whey threatens consumer health and reduces quality of mozzarella cheese. The goal of this research was to evaluate the acidification process of acid whey (whole and deproteinized) by fermentation with different inoculum concentrations of Lactobacillus casei. The whey was physicochemically characterized and anaerobically fermented at 37°C and120 rpm during 96h. Cellular biomass was evaluated, as well as lactose consumption, lactic acid production, kinetic and stoichiometric parameters were estimated. A completely randomized design with factorial arrangement (2x3) was applied by using the repeated measures methodology. Data was processed by using SAS® statistical package, version 9 and Statgraphics Centurion XVI®. The acidification for the whole and deproteinized whey was found within the acceptable intervals. Acidification values were above 120 degrees Dornic (120°D) with L. casei inoculation, except in the deproteinized whey inoculated with 15% of inoculum. The whole whey with 15% of inoculum reached 120°D in the shortest time (34 hours). High concentrations of inoculum (15%) aided the acidification in whole whey and showed the highest production (20.83 g LA/l), and p/s=0.86, Qp=0.173 g AL/l*h; on the other hand, the deproteinized whey showed the highest microbial growth, lowest conversion of lactose (8.2%) and lowest lactic acid production (8.19g/l).

Asymmetric regression models with limited responses with an application to antibody response to vaccine.

We develop regression models for limited and censored data based on the mixture between the log-power-normal and Bernoulli-type distributions. A likelihood-based approach is implemented for parameter estimation and a small-scale simulation study is conducted to evaluate parameter recovery, with emphasis on bias estimation. The main conclusion is that the approach is very much satisfactory for moderate and large sample sizes. A real data example, the safety and immunogenecity study of measles vaccine in Haiti, is presented to illustrate how different models can be used to fit this type of data. As shown, the asymmetric models considered seem to present the best fit for the data set under study, revealing significance of the explanatory variable sex, which is not found significant with the log-normal model.

Lesión de la glándula suprarrenal por trauma penetrante: reporte de un caso y revisión de la literatura / Adrenal gland injury in penetrating trauma: case report and literature review

Se presenta el caso de un paciente que recibió una herida por proyectil de arma de fuego en abdomen que le ocasionó una lesión grado III de la glándula suprarrenal izquierda. Fue manejado conservadoramente con empaquetamiento perirrenal, con buena evolución clínica posquirúrgica y sin presentar signos de insuficiencia suprarrenal.El trauma suprarrenal es una patología muy poco frecuente, debida probablemente a la localización y el tamaño de la glándula. Su manejo debe estar enfocado al control de la hemorragia y la prevención de la suprarrenalectomía para preservar su función endocrina.

Abdomen abierto en sepsis intraabodminal: malla de nylon con cierre / Open abdomen in intraabdominal sepsis: nylon mesh with zipper

La sepsis intraabdominal presenta una mortalidad entre 30% y 80% con el manejo tradicional de laparotomia y drenaje del foco septico. En la literatura se han descrito varios metodos para prevenir la reacumulacion de la sepsis. Se muestra la experiencia en el Hospital Universitario del Valle, Cali, Colombia. Se manejaron en un periodo de 18 meses, 65 pacientes con sepsis abdominal con el abdomen abierto y malla de plastico inicialmetne y luego con malla de mylon con cierre de cremallera. Se describe la tecnica para la colocacion de la malla y el manejo de los lavados abdominales cada 24 horas en la cama del paciente bajo sedacion. Los pacientes se les agrupo segun la clasificacion anatomica, se midio el APACHE II, el PATI y se correlaciono con la mortalidad. La principal indicacion para la colocacion de la malla fue la peritonitis generalizada difusa. Se ralizaron 4.74 lavados en promedio para los pacientes que sobrevivieron y el numero promedio de dias con la malla fue 11.3. La mortalidad para los pacientes con malla y lavados fue 31.5