A Multiple Objective Formulation and Algorithm for the Layout Design of Food Processing Facilities.

A multiple objective formulation, which incorporates robustness and constraint enforcement as design criteria, is utilized to model the layout of food processing facilities. These facilities are subject to the compliance with guidelines dictated by public health agencies, changes in product mix, and variation in production levels due to seasonality, which render existing layout design algorithms unsuitable for their design. The solution of the robust multiple objective formulation is implemented using a construction heuristic algorithm, MORCH, and an improvement heuristics, MOLAD. The MORCH/MOLAD hybrid algorithm performs comparably to well known heuristic algorithms where materials handling cost is used as the only design criterion. Also, the MORCH/MOLAD solutions are more robust than those of robust heuristic algorithms. Moreover, through the use of a qualitative constraint matrix, the hybrid algorithm generates layouts that conform to guidelines imposed by U.S. regulatory agencies without significantly penalizing materials handling cost. As a qualitative constraint matrix in conjunction with materials handling cost are present in the model, a multicriteria decision making aid that deals with qualitative and quantitative factors, the Analytic Hierarchy Process, is used to select the most suitable layout and to guide the generation of and search for good alternative layout solutions by the hybrid algorithm

Superparamagnetic Poly (3-hydroxybutyrate-co-3 hydroxyvalerate) (PHBV) nanoparticles for biomedical applications

Indexación: ScieloBackground: The progress in material science and the recent advances in biodegradable/biocompatible polymers and magnetic iron oxide nanoparticles have led to develop innovative diagnostic and therapeutic strategies for diseases based on multifunctional nanoparticles, which include contrast medium for magnetic resonance imaging, agent for hyperthermia and nanocarriers for targeted drug delivery. The aim of this work is to synthesize and characterize superparamagnetic iron oxide (magnetite), and to encapsulate them into poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) nanoparticles for biomedical applications. Results: The magnetite nanoparticles were confirmed by X-ray diffraction and exhibited a size of 22.3 ± 8.8 nm measured by transmission electron microscopy (TEM). Polymeric PHBV nanoparticles loaded with magnetite (MgNPs) were analyzed using dynamic light scattering and showed a size of 258.6 ± 35.7 nm and a negative zeta potential (-10.8 ± 3.5 mV). The TEM examination of MgNPs exhibited a spherical core-shell structure and the magnetic measurements showed in both, non-encapsulated magnetite and MgNPs, a superparamagnetic performance. Finally, the in vitro studies about the magnetic retention of MgNPs in a segment of small intestine of rats showed an active accumulation in the region of the magnetic field. Conclusions: The results obtained make the MgNPs suitable as potential magnetic resonance imaging contrast agents, also promoting hyperthermia and even as potential nanocarriers for site-specific transport and delivery of drugs. Keywords: hyperthermia, magnetic resonance image (MRI), magnetite, PHBV, polymeric nanoparticles.http://ref.scielo.org/cxt57

Integrated approach to assignment, scheduling and routing problems

This research considers a real life case study that determines the minimum number of sellers required to attend a set of customers located in a certain region taking into account the weekly schedule plan of the visits, as well as the optimal route. The problem is formulated as a combination of assignment, scheduling and routing problems. In the new formulation, case studies of small size subset of customers of the above type can be solved optimally. However, this subset of customers is not representative within the business plan of the company. To overcome this limitation, the problem is divided into three phases. A greedy algorithm is used in Phase I in order to identify a set of cost-effective feasible clusters of customers assigned to a seller. Phase II and III are then used to solve the problem of a weekly program for visiting the customers as well as to determine the route plan using MILP formulation. Several real life instances of different sizes have been solved demonstrating the efficiency of the proposed approach

Factores asociados a la adherencia al tratamiento antirretroviral en pacientes que conviven con el VIH-SIDA atendidos en la consulta externa del Hospital Alemán Nicaragüense en el periodo comprendido Enero-Febrero del año 2020

Se realizó estudio para determinar los factores asociados a la adherencia al tratamiento antirretroviral en pacientes que conviven con VIH-SIDA atendidos en la consulta externa del Hospital Alemán Nicaragüense, durante los meses Enero a Febrero del 2020. El estudio fue de tipo descriptivo, observacional y de carácter transversal, con 830 pacientes que se atienden en la consulta, del cual se realizó muestreo probabilístico aleatorio en base a formula estadística, donde se estimó como muestra el total de 163 pacientes. Se recolectó los datos mediante encuesta realizada previamente por el investigador con entrevista directa a los pacientes y se procedió a realizar una base de datos en el paquete estadístico SPSS 25.0 para la realización de las tablas y gráficos. Entre los factores encontrados en los pacientes que influyeron en la adherencia encontrada en los pacientes fueron: la mayoría eran del sexo masculino, de 26 a 30 años, como habito toxico más frecuente se constató el consumo de alcohol, no presentaban enfermedades psiquiátricas y comorbilidades crónicas en su mayoría presentaban HTA y cardiopatía. El medicamento más utilizado fue la Atripla, el cual se administra una vez al día. Los pacientes presentaron un conocimiento de las TAR adecuado y las actitudes hacia la misma fueron favorables, así como también el actuar medico fue aprobado por la mayoría de los pacientes. El 44% de la muestra se encontraban en categoría 1 de conteo de células CD4, mayor de 500 células por ml3 Se encontró con todos estos factores una adherencia de un 80% y con nivel de adherencia elevado (grado A y B), todo esto medido a través del cuestionario SMAQ (Simplified Medication Adherence Questionaire) validado internacionalmente para valorar la adherencia a la TA

Integrated Approach to Assignment, Scheduling and Routing Problems in a Sales Territory Business Plan

AbstractThis paper considers a real life case study that determines the minimum number of sellers required to attend a set of customers located in a certain region taking into account the weekly schedule plan of the visits, as well as the optimal route. The problem is formulated as a combination of assignment, scheduling and routing problems. In the new formulation, case studies of small size subset of customers of the above type can be solved optimally. However, this subset of customers is not representative within the business plan of the company. To overcome this limitation, the problem is divided into three phases. A greedy algorithm is used in Phase I in order to identify a set of cost-effective feasible clusters of customers assigned to a seller. Phase II and III are then used to solve the problem of a weekly program for visiting the customers as well as to determine the route plan using MILP formulation. Several real life instances of different sizes have been solved demonstrating the efficiency of the proposed approach

Recommendations for Future Articles on Knowledge, Attitudes and Practices in IJMS

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Transparency in the International Journal of Medical Students

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Poster Presentations: A Presenting Opportunity in Conferences for Medical Students

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Fisiopatología de los movimientos oculares en la parálisis cerebral infantil

Cerebral palsy is a permanent and non-progressive brain damage due to various causes affecting a child from the intrauterine life up to the first two years of life. Its most common cause is neonatal hypoxic encephalopathy. The cerebral damage is diffuse so that it is commonly associated with epilepsy, mental retardation, dysarthria, hearing loss and oculomotor abnormalities. Strabismus is found in 50 % of children with cerebral palsy. This prevalence is significantly different from the 2 % incidence of oculomotor abnormalities in the pre-school age, it is noteworthy that strabismus and refractivo errors respond to the classical therapeutic measures

Análisis de accesibilidad aplicado a la distribución de gas natural comprimido

A continuación se presenta la aplicación de una propuesta metodológica de estudio de accesibilidad territorial para el suministro de Gas Natural Comprimido (GNC) en una región específica del departamento de Caldas, Colombia. Se tiene en cuenta las proyecciones de consumo del producto y las diferentes variables de tipo geográfico e infraestructuras de transporte que permitan una eficiente logística de entrega a las poblaciones objeto, y su relación con los posibles puntos de distribución. El principal objetivo es establecer el mejor  punto de distribución de GNC para proveer a dos corredores viales del departamento. Se realiza un análisis multicriterio de las variables