Ruteo de vehículos escolares: caso de estudio de la Universidad Autónoma de Coahuila

En este trabajo se proponen un conjunto de nuevas rutas de transporte para dar servicio a la comunidad estudiantil actual del Campus Arteaga de la Universidad Autónoma de Coahuila atendiendo a la dispersidad de los estudiantes en la zona metropolitana de Saltillo. Se analiza un caso de estudio con la información de una Facultad, considerando 380 estudiantes y 46 paradas correspondientes a las colonias de Saltillo. El problema se formula matemáticamente como un modelo lineal entero mixto, el cual es resuelto a través de un optimizador comercial. Con el modelo sólo es posible resolver a optimalidad instancias de 10 paradas y 50 estudiantes, por lo que se diseñó un algoritmo heurístico constructivo híbrido basado en el algoritmo de Clarke y Wright, en donde la factibilidad de una solución se verifica al resolver una versión simplificada del modelo matemático. Se implementan dos estrategias para reducir el tiempo de cómputo del algoritmo heurístico y se reportan las nuevas rutas propuestas, así como algunas recomendaciones para facilitar la construcción de las instancias del problema

Post-Franco Theatre

In the multiple realms and layers that comprise the contemporary Spanish theatrical landscape, “crisis” would seem to be the word that most often lingers in the air, as though it were a common mantra, ready to roll off the tongue of so many theatre professionals with such enormous ease, and even enthusiasm, that one is prompted to wonder whether it might indeed be a miracle that the contemporary technological revolution – coupled with perpetual quandaries concerning public and private funding for the arts – had not by now brought an end to the evolution of the oldest of live arts, or, at the very least, an end to drama as we know it

Is diet partly responsible for differences in COVID-19 death rates between and within countries?

Correction: Volume: 10 Issue: 1 Article Number: 44 DOI: 10.1186/s13601-020-00351-w Published: OCT 26 2020Reported COVID-19 deaths in Germany are relatively low as compared to many European countries. Among the several explanations proposed, an early and large testing of the population was put forward. Most current debates on COVID-19 focus on the differences among countries, but little attention has been given to regional differences and diet. The low-death rate European countries (e.g. Austria, Baltic States, Czech Republic, Finland, Norway, Poland, Slovakia) have used different quarantine and/or confinement times and methods and none have performed as many early tests as Germany. Among other factors that may be significant are the dietary habits. It seems that some foods largely used in these countries may reduce angiotensin-converting enzyme activity or are anti-oxidants. Among the many possible areas of research, it might be important to understand diet and angiotensin-converting enzyme-2 (ACE2) levels in populations with different COVID-19 death rates since dietary interventions may be of great benefit.Peer reviewe

Incorporating location, routing, and inventory decisions in a bi-objective supply chain design problem with risk-pooling

This paper considers a single-sourcing network design problem for a three-level supply chain. For the first time, a novel mathematical model is presented considering risk-pooling, the inventory existence at distribution centers (DCs) under demand uncertainty, the existence of several alternatives to transport the product between facilities, and routing of vehicles from distribution centers to customer in a stochastic supply chain system, simultaneously. This problem is formulated as a bi-objective stochastic mixed-integer nonlinear programming model. The aim of this model is to determine the number of located distribution centers, their locations, and capacity levels, and allocating customers to distribution centers and distribution centers to suppliers. It also determines the inventory control decisions on the amount of ordered products and the amount of safety stocks at each opened DC, selecting a type of vehicle for transportation. Moreover, it determines routing decisions, such as determination of vehicles' routes starting from an opened distribution center to serve its allocated customers and returning to that distribution center. All are done in a way that the total system cost and the total transportation time are minimized. The Lingo software is used to solve the presented model. The computational results are illustrated in this paper

Stem cell and gene therapies for diabetes mellitus

10.1038/nrendo.2009.276Nature Reviews Endocrinology63173-17