El Outsourcing en la dinámica de sistemas hacia mercados extranjeros

Este trabajo recopila literatura académica relevante sobre estrategias de entrada y metodologías para la toma de decisión sobre la contratación de servicios de Outsourcing para el caso de empresas que planean expandirse hacia mercados extranjeros. La manera en que una empresa planifica su entrada a un mercado extranjero, y realiza la consideración y evaluación de información relevante y el diseño de la estrategia, determina el éxito o no de la misma. De otro lado, las metodologías consideradas se concentran en el nivel estratégico de la pirámide organizacional. Se parte de métodos simples para llegar a aquellos basados en la Teoría de Decisión Multicriterio, tanto individuales como híbridos. Finalmente, se presenta la Dinámica de Sistemas como herramienta valiosa en el proceso, por cuanto puede combinarse con métodos multicriterio.

Análisis de las trayectorias de dolor posoperatorio, primera hora vs. 24 horas. Estudio observacional en 234 pacientes

Introducción: El dolor posoperatorio no controlado es un predictor de dolor severo. La trayectoria de dolor durante la primera hora podría predecir el curso del dolor durante las primeras 24 horas. El control temprano del dolor posoperatorio facilita el manejo analgésico durante el primer día y mejora la experiencia del paciente, facilitando su recuperación y rehabilitación. Objetivo: Determinar la relación entre la trayectoria del dolor en la primera hora y durante las 24 horas post-operatorias. Material y métodos: Estudio analítico observacional prospectivo de 234 pacientes llevados a procedimientos quirúrgicos bajo anestesia general. Se registraron 8 intesidades de dolor durante las 24 horas. Se calcularon las pendientes y se estableció la relación entre ellas. Resultados: El 31,3% de pacientes tenían dolor no controlado al ingreso a recuperación. La intensidad del dolor al inicio se correlaciona de forma negativa con la trayectoria de la primera hora P1 rS= -0,657 (p=0.000). La intensidad de dolor inicial tiene una asociación negativa con P2 de rS= -0.141 (p=0.032). Al compararse las pendientes P1 y P2 y se encontró una correlación negativa muy baja rS= -0.126 (p=0.056). Conclusiones: Uno de cada tres pacientes presenta dolor severo durante el posoperatorio agudo. La trayectoria del dolor en la primera hora no permite predecir el comportamiento de la trayectoria durante el primer día posoperatorio. El comportamiento del dolor está relacionado con la intensidad al final de la anestesia. Cuando el dolor inicial es severo alcanzar la meta analgésica tarda más tiempo.

Análisis de supervivencia en pacientes con prótesis valvular biológica, Fundación Cardioinfantil-Instituto de Cardiología, Colombia, 2005-2013

Introducción: A partir de la década de los cincuenta el manejo de la enfermedad valvular presenta cambios significativos cuando se incorporan los reemplazos valvulares tanto mecánicos como biológicos dentro de las opciones de tratamiento quirúrgico (1). Las válvulas biológicas se desarrollaron como una alternativa que buscaba evitar los problemas relacionados con la anticoagulación y con la idea de utilizar un tejido que se comportara hemodinámicamente como el nativo. Este estudio está enfocado en establecer la sobrevida global y la libertad de reoperación de la válvula de los pacientes sometidos a reemplazo valvular aórtico y mitral biológicos en la Fundación Cardioinfantil - IC a 1, 3, 5 y 10 años. Materiales y métodos: Estudio de cohorte retrospectiva de supervivencia de pacientes sometidos a reemplazo valvular aórtico y/o mitral biológico intervenidos en la Fundación Cardioinfantil entre 2005 y 2013. Resultados: Se obtuvieron 919 pacientes incluidos en el análisis general y 876 (95,3%) pacientes con seguimiento efectivo para el análisis de sobrevida. La edad promedio fue 64años. La sobrevida a 1, 3, 5 y 10 años fue 95%,90%,85% y 69% respectivamente. El seguimiento efectivo para el desenlace reoperación fue del 55% y se encontró una libertad de reoperación del 99%, 96%, 93% y 81% a los 1, 3, 5 y 10 años. No hubo diferencias significativas entre la localización de la válvula ni en el tipo de válvula aortica empleada. Conclusiones: La sobrevida de los pacientes que son llevados a reemplazo valvular biológico en este estudio es comparable a grandes cohortes internacionales. La sobrevida de los pacientes llevados a reemplazo valvular con prótesis biológicas en posición mitral y aortica fue similar a 1, 3, 5 y 10 años.

Study of the mechanism of action of anoplin, a helical antimicrobial decapeptide with ion channel-like activity, and the role of the amidated C-terminus

Anoplin, an antimicrobial, helical decapeptide from wasp venom, looses its biological activities by mere deamidation of its C-terminus. Secondary structure determination, by circular dichroism spectroscopy in amphipathic environments, and lytic activity in zwitterionic and anionic vesicles showed quite similar results for the amidated and the carboxylated forms of the peptide. The deamidation of the C-terminus introduced a negative charge at an all-positive charged peptide, causing a loss of amphipathicity, as indicated by molecular dynamics simulations in TFE/water mixtures and this subtle modification in a peptide`s primary structure disturbed the interaction with bilayers and biological membranes. Although being poorly lytic, the amidated form, but not the carboxylated, presented ion channel-like activity on anionic bilayers with a well-defined conductance step; at approximately the same concentration it showed antimicrobial activity. The pores remain open at trans-negative potentials, preferentially conducting cations, and this situation is equivalent to the interaction of the peptide with bacterial membranes that also maintain a high negative potential inside. Copyright (C) 2007 European Peptide Society and John Wiley & Sons, Ltd.

Study of Blood Porphyrin Spectral Profile for Diagnosis of Chronic Renal Failure

The progression to end-stage renal failure is independent of the initial pathogenic mechanism. Metabolic acidosis is a common consequence of chronic renal failure that results from inadequate ammonium excretion and decreased tubular bicarbonate reabsorption. Protoporphyrin IX (PpIX) is the immediate metabolic precursor of the heme molecule. The purpose of this study was to evaluate the levels of erythrocytes protoporphyrin IX at an animal model during progressive renal disease. A total of 36 eight-week-old male Wistar rats were divided into six groups: Normal, 4 and 8 weeks after 5/6 nephrectomy (NX). Renal function was evaluated by creatinine clearance and plasma creatinine levels. The autofluorescence of erythrocytes porphyrin of healthy and NX rats was analyzed using fluorescence spectroscopy. Emission spectra were obtained by exciting the samples at 405 nm. Significant differences between normal and NX rats autofluorescence shape occurred in the 600-700 nm spectral region. A correlation was observed between emission band intensity at 635 nm and progression of renal disease.

Study of photorespiration in marine microalgae through the determination of glycolic acid using hydrophilic interaction liquid chromatography

Determination of organic acids in intracellular extracts and in the cultivation media of marine microalgae aid investigations about metabolic routes related to assimilation of atmospheric carbon by these organisms, which are known by their role in the carbon dioxide sink. The separation of these acids was investigated by hydrophilic interaction liquid chromatography (HILIC) using isocratic elution with a mobile phase composed of 70: 30 v/v acetonitrile/20 mmol/L ammonium acetate buffer (pH 6.8) and detection at 220 nm. HILIC allowed the determinations of glycolic acid, the most important metabolite for the evaluation of the photorespiration process in algae, to be made with better selectivity than that achieved by reversed phase liquid chromatography, but with less detectability. The concentration of glycolic acid was determined in the cultivation media and in intracellular extracts of the algae Tetraselmis gracilis and Phaeodactylum tricornutum submitted to different conditions of aeration: (i) without forced aeration, (ii) aeration with atmospheric air, and (iii) bubbling with N(2). The concentration of glycolic acid had a higher increase as the cultures were aerated with nitrogen, showing higher photorespiratory flux than that occurring in the cultures aerated with atmospheric air.

Predicting the population impact of chlamydia screening programmes: comparative mathematical modelling study

BACKGROUND: Published individual-based, dynamic sexual network modelling studies reach different conclusions about the population impact of screening for Chlamydia trachomatis. The objective of this study was to conduct a direct comparison of the effect of organised chlamydia screening in different models. METHODS: Three models simulating population-level sexual behaviour, chlamydia transmission, screening and partner notification were used. Parameters describing a hypothetical annual opportunistic screening program in 16-24 year olds were standardised, whereas other parameters from the three original studies were retained. Model predictions of the change in chlamydia prevalence were compared under a range of scenarios. RESULTS: Initial overall chlamydia prevalence rates were similar in women but not men and there were age and sex-specific differences between models. The number of screening tests carried out was comparable in all models but there were large differences in the predicted impact of screening. After 10 years of screening, the predicted reduction in chlamydia prevalence in women aged 16-44 years ranged from 4% to 85%. Screening men and women had a greater impact than screening women alone in all models. There were marked differences between models in assumptions about treatment seeking and sexual behaviour before the start of the screening intervention. CONCLUSIONS: Future models of chlamydia transmission should be fitted to both incidence and prevalence data. This meta-modelling study provides essential information for explaining differences between published studies and increasing the utility of individual-based chlamydia transmission models for policy making.

Effects of exercise on anxiety and depression disorders: Review of meta-analyses and neurobiological mechanisms

Anxiety and depression are the most frequently diagnosed psychological diseases showing a high co-morbidity. They have a severe impact on the lives of the persons concerned. Many meta-analytical studies suggested a positive anxiolytic and depression reducing effect of exercise programs. The aim of the present article is to synthesize metaanalyses on the effects of exercise on anxiety and depression and to describe average effect sizes. For this purpose 37 meta-analyses were included reporting 50 effect sizes for anxiety scores of 42,264 participants and depression scores of 48,207 persons. The average documented anxiolytic effect of exercise in these reviews was small, 0.34. In contrast, the effect of exercise on depression was significantly higher and at a moderate level, 0.56. Data of randomized controlled trials suggest higher sizes for the effect of exercise on anxiety and depression leading to increases up to moderate and large effects, respectively. Additionally, exercise seems to be more beneficial for patients compared to participants within a nonclinical, normal range of psychological disease. Especially for the effect of exercise on anxiety, more high quality meta-analyses of randomized controlled trials are needed. Finally, possible neurobiological explanations are suggested for the positive effect of exercise on psychological disorders like anxiety and depression.

Analytical Models of Exoplanetary Atmospheres. II. Radiative Transfer via the Two-Stream Approximation

We present a comprehensive analytical study of radiative transfer using the method of moments and include the effects of non-isotropic scattering in the coherent limit. Within this unified formalism, we derive the governing equations and solutions describing two-stream radiative transfer (which approximates the passage of radiation as a pair of outgoing and incoming fluxes), flux-limited diffusion (which describes radiative transfer in the deep interior) and solutions for the temperature-pressure profiles. Generally, the problem is mathematically under-determined unless a set of closures (Eddington coefficients) is specified. We demonstrate that the hemispheric (or hemi-isotropic) closure naturally derives from the radiative transfer equation if energy conservation is obeyed, while the Eddington closure produces spurious enhancements of both reflected light and thermal emission. We concoct recipes for implementing two-stream radiative transfer in stand-alone numerical calculations and general circulation models. We use our two-stream solutions to construct toy models of the runaway greenhouse effect. We present a new solution for temperature-pressure profiles with a non-constant optical opacity and elucidate the effects of non-isotropic scattering in the optical and infrared. We derive generalized expressions for the spherical and Bond albedos and the photon deposition depth. We demonstrate that the value of the optical depth corresponding to the photosphere is not always 2/3 (Milne's solution) and depends on a combination of stellar irradiation, internal heat and the properties of scattering both in optical and infrared. Finally, we derive generalized expressions for the total, net, outgoing and incoming fluxes in the convective regime.

Initial orthodontic alignment effectiveness with self-ligating and conventional appliances: a network meta-analysis in practice.

Systematic reviews of well-designed trials constitute a high level of scientific evidence and are important for medical decision making. Meta-analysis facilitates integration of the evidence using a transparent and systematic approach, leading to a broader interpretation of treatment effectiveness and safety than can be attained from individual studies. Traditional meta-analyses are limited to comparing just 2 interventions concurrently and cannot combine evidence concerning multiple treatments. A relatively recent extension of the traditional meta-analytical approach is network meta-analysis, which allows, under certain assumptions, the quantitative synthesis of all evidence under a unified framework and across a network of all eligible trials. Network meta-analysis combines evidence from direct and indirect information via common comparators; interventions can therefore be ranked in terms of the analyzed outcome. In this article, the network meta-analysis approach is introduced in a nontechnical manner using a worked example on the treatment effectiveness of conventional and self-ligating appliances.

Irrational Beliefs and Psychological Distress: A Meta-Analysis

Background: Since the cognitive revolution of the early 1950s, cognitions have been discussed as central components in the understanding and treatment of mental illnesses. Even though there is an extensive literature on the association between therapy-related cognitions such as irrational beliefs and psychological distress over the past 60 years, there is little meta-analytical knowledge about the nature of this association. Methods: The relationship between irrational beliefs and distress was examined based on a systematic review that included 100 independent samples, gathered in 83 primary studies, using a random-effect model. The overall effects as well as potential moderators were examined: (a) distress measure, (b) irrational belief measure, (c) irrational belief type, (d) method of assessment of distress, (e) nature of irrational beliefs, (f) time lag between irrational beliefs and distress assessment, (g) nature of stressful events, (h) sample characteristics (i.e. age, gender, income, and educational, marital, occupational and clinical status), (i) developer/validator status of the author(s), and (k) publication year and country. Results: Overall, irrational beliefs were positively associated with various types of distress, such as general distress, anxiety, depression, anger, and guilt (omnibus: r = 0.38). The following variables were significant moderators of the relationship between the intensity of irrational beliefs and the level of distress: irrational belief measure and type, stressful event, age, educational and clinical status, and developer/validator status of the author. Conclusions: Irrational beliefs and distress are moderately connected to each other; this relationship remains significant even after controlling for several potential covariates.

A Meta-analytic Review of Acceptance-Based Behavioral Interventions for the Treatment of Anxiety

The relative popularity of acceptance and commitment therapy (ACT) has grown in recent years, and inspired the development of contemporary acceptance-based treatment approaches. Acceptance-based therapies differ from traditional cognitive- behavior therapy (CBT) on pragmatic grounds, the import of which implicates the purpose of therapy. CBT utilizes exposure and cognitive change techniques primarily in service of symptom change outcomes; whereas, ACT utilizes exposure and acceptance for purposes of promoting psychological flexibility in the pursuit of personal values. The purpose of this meta-analytic study was to determine the relative efficacy of acceptance- based versus symptom-change behavioral approaches with anxiety disorders and to quantify this impact. A comprehensive literature search turned up 18 studies that met inclusion criteria for this analysis. An effect size was calculated using the standardized mean gain procedure for both the acceptance-based and symptom-change approaches, along with the waitlist control groups. The results demonstrate a large effect size for the acceptance-based approach (Weighted mean ES = .83) and a medium effect size for symptom-change approach (Weighted mean ES = .60). The waitlist control groups demonstrated a small effect size (Weighted mean ES = .24). Based on this review, it is suggested that graduate and internship programs in Clinical Psychology should promote evidence-based training in the use of acceptance-inspired behavioral therapies.

Study of tRNA modifying enzymes and codon usage bias in cancer

Recent evidences indicate that tRNA modifications and tRNA modifying enzymes may play important roles in complex human diseases such as cancer, neurological disorders and mitochondrial-linked diseases. We postulate that expression deregulation of tRNA modifying enzymes affects the level of tRNA modifications and, consequently, their function and the translation efficiency of their tRNA corresponding codons. Due to the degeneracy of the genetic code, most amino acids are encoded by two to six synonymous codons. This degeneracy and the biased usage of synonymous codons cause alterations that can span from protein folding to enhanced translation efficiency of a select gene group. In this work, we focused on cancer and performed a meta-analysis study to compare microarray gene expression profiles, reported by previous studies and evaluate the codon usage of different types of cancer where tRNA modifying enzymes were found de-regulated. A total of 36 different tRNA modifying enzymes were found de-regulated in most cancer datasets analyzed. The codon usage analysis revealed a preference for codons ending in AU for the up-regulated genes, while the down-regulated genes show a preference for GC ending codons. Furthermore, a PCA biplot analysis showed this same tendency. We also analyzed the codon usage of the datasets where the CTU2 tRNA modifying enzyme was found deregulated as this enzyme affects the wobble position (position 34) of specific tRNAs. Our data points to a distinct codon usage pattern between up and downregulated genes in cancer, which might be caused by the deregulation of specific tRNA modifying enzymes. This codon usage bias may augment the transcription and translation efficiency of some genes that otherwise, in a normal situation, would be translated less efficiently.

Prevalence of preterm labor in Iran: A systematic review and meta-analysis

Background: Preterm labor, which defines as live-birth delivery before 37 weeks of gestation is a main determinant of neonatal morbidity and mortality around the world. Objective: The aim of this study was to determine the prevalence of preterm labor in Iran by a meta-analysis study, to be as a final measure for policy makers in this field. Materials and Methods: In this meta-analysis, the databases of Thomson database (Web of Knowledge), PubMed/Medline, Science Direct, Scopus, Google Scholar, Iranmedex, Scientific Information Database (SID), Magiran, and Medlib were searched for articles in English and Persian language published between 1995 and 2014. Among the studies with regard to the inclusion and exclusion criteria, 14 studies (out of 1370 publications) were selected. Data were analyzed by using Stata software version 11. The heterogeneity of reported prevalence among studies was evaluated by the Chi-square based Q test and I2 statistics. Results: The results of Chi-square based on Q test and I2 statistics revealed severe heterogeneity (Q=2505.12, p-value < 0.001 and I2= 99.5%) and consequently, the random effect model was used for the meta-analysis. Based on the random effect model, the overall estimated prevalence of preterm in Iran was 9.2% (95% CI: 7.6 – 10.7). Conclusion: Present study summarized the results of previous studies and provided a comprehensive view about the preterm delivery in Iran. In order to achieve a more desirable level and its reduction in the coming years, identifying affecting factor and interventional and preventive actions seem necessary.

Entrepreneurship: a long way to go

Entrepreneurship education has emerged as one popular research domain in academic fields given its aim at enhancing and developing certain entrepreneurial qualities of undergraduates that change their state of behavior, even their entrepreneurial inclination and finally may result in the formation of new businesses as well as new job opportunities. This study attempts to investigate the Colombian student´s entrepreneurial qualities and the influence of entrepreneurial education during their studies.