Numerical validation of a population balance model describing cement paste rheology

Rheology control is essential during the period in which cement and concrete pastes are encountered in the fresh state, due to the fact that it directly affects workability, initial placement and the structural performance of the hardened material. Optimizations of clinker formulations and reductions in cement-to-water ratios induced by economic and environmental considerations have a significant effect in rheology, which invokes the need for mechanistic models capable of describing the effect of multiple relevant phenomena on the observed paste flow. In this work, the population balance framework was implemented to develop a model able to relate the transient microstructural evolution of cement pastes under typical experimental conditions with its macroscopic rheological responses. Numerical details and performance are assessed and discussed. It was found that the model is capable of reproducing experimentally observed flow curves by using measured cluster size distribution information. It is also able to predict the complex rheological characteristics typically found in cement pastes. Furthermore, a spatially resolved scheme was proposed to investigate the nature of flow inside a parallel-plates rheometer geometry with the objective of assessing the ability of the model of qualitatively predicting experimentally observed behavior and to gain insight into the effect of possible secondary flows

Vitamin D, a modulator of musculoskeletal health in chronic kidney disease

The spectrum of activity of vitamin D goes beyond calcium and bone homeostasis, and growing evidence suggests that vitamin D contributes to maintain musculoskeletal health in healthy subjects as well as in patients with chronic kidney disease (CKD), who display the combination of bone metabolism disorder, muscle wasting, and weakness. Here, we review how vitamin D represents a pathway in which bone and muscle may interact. In vitro studies have confirmed that the vitamin D receptor is present on muscle, describing the mechanisms whereby vitamin D directly affects skeletal muscle. These include genomic and non‐genomic (rapid) effects, regulating cellular differentiation and proliferation. Observational studies have shown that circulating 25‐hydroxyvitamin D levels correlate with the clinical symptoms and muscle morphological changes observed in CKD patients. Vitamin D deficiency has been linked to low bone formation rate and bone mineral density, with an increased risk of skeletal fractures. The impact of low vitamin D status on skeletal muscle may also affect muscle metabolic pathways, including its sensitivity to insulin. Although some interventional studies have shown that vitamin D may improve physical performance and protect against the development of histological and radiological signs of hyperparathyroidism, evidence is still insufficient to draw definitive conclusions

Online economic calculator for crop treatments applications-Africa version-

Presentación en diapositivas (inglés)INTA and AAPRESID signed Specific Cooperation Agreement (2019, underrenewal) for the Proje "Design, implementationand Technology Development for Conservation Agriculture in Ghanaand Guinea" , with the participation of Pablo Abbate, to provide technical/scientificadvice. In 2018 Abbate and others began to develop an interactive website to disseminate agronomic information in Argentina. Today there are more than 15 interactive pages, with free and open access, in which 18 authors from more than 10 national and foreign, public and private institutions have participated: https://cultivaresargentinos.comEEA BalcarceFil: Abbate, Pablo Eduardo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina.Fil: Edwards Molina, Juan. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina.Fil: Bronzovich, Nicolás. Asociación Argentina de Productores en Siembra Directa; Argentina

Colonic perforation due to invasive amebic colitis during anti-TNF therapy for spondyloarthritis

AbstractTNF blockade has been successful in the treatment of some rheumatic diseases such as spondyloarthritis. Many infectious complications have been reported with anti-TNF therapy, mainly bacterial, mycobacterial, viral and fungal infections. Entamoeba histolytica is an extracellular protozoan parasite that mainly causes colitis and hepatic abscess; bowel perforation is an uncommon complication with high mortality. TNF is considered the principal mediator of cell immunity against amebiasis. Initially, it is chemotactic to E. histolytica, enhancing its adherence to enterocyte via galactose inhibitable lectin, and then activating macrophages to kill ameba though the release of NO, so that TNF blocking could be harmful, increasing amebic virulence. We describe the case of a 46-year-old woman with spondyloarthritis who presented a colonic perforation due to invasive amebic colitis during anti-TNF use

Incidencia de problemas relacionados con medicamentos durante la estancia hospitalaria.

49 Páginas.Los errores de medicación constituyen el 20% de los eventos adversos a nivel hospitalario; afectan la seguridad de los pacientes, prolongan estancia hospitalaria y generan costos adicionales. La incidencia de los problemas relacionados con medicamentos (PRM) ha encendido alarmas de preocupación a nivel mundial, y se han convertido en un indicador de la calidad del cuidado sanitario, estimulando la implementación de estrategias para prevenir o reducir el daño a los pacientes. La realización de este proyecto permitió una aproximación a la realidad fármacoepidemiológica de la Clínica Universidad de La Sabana y fortaleció el sistema de uso seguro de medicamentos. El 39% de los pacientes tuvieron mínimo un PRM durante la estancia hospitalaria. Los problemas de indicación fueron los más frecuentes

A Review of Symbolic, Subsymbolic and Hybrid Methods for Sequential Decision Making

The field of Sequential Decision Making (SDM) provides tools for solving Sequential Decision Processes (SDPs), where an agent must make a series of decisions in order to complete a task or achieve a goal. Historically, two competing SDM paradigms have view for supremacy. Automated Planning (AP) proposes to solve SDPs by performing a reasoning process over a model of the world, often represented symbolically. Conversely, Reinforcement Learning (RL) proposes to learn the solution of the SDP from data, without a world model, and represent the learned knowledge subsymbolically. In the spirit of reconciliation, we provide a review of symbolic, subsymbolic and hybrid methods for SDM. We cover both methods for solving SDPs (e.g., AP, RL and techniques that learn to plan) and for learning aspects of their structure (e.g., world models, state invariants and landmarks). To the best of our knowledge, no other review in the field provides the same scope. As an additional contribution, we discuss what properties an ideal method for SDM should exhibit and argue that neurosymbolic AI is the current approach which most closely resembles this ideal method. Finally, we outline several proposals to advance the field of SDM via the integration of symbolic and subsymbolic AI

NeSIG: A Neuro-Symbolic Method for Learning to Generate Planning Problems

In the field of Automated Planning there is often the need for a set of planning problems from a particular domain, e.g., to be used as training data for Machine Learning or as benchmarks in planning competitions. In most cases, these problems are created either by hand or by a domain-specific generator, putting a burden on the human designers. In this paper we propose NeSIG, to the best of our knowledge the first domain-independent method for automatically generating planning problems that are valid, diverse and difficult to solve. We formulate problem generation as a Markov Decision Process and train two generative policies with Deep Reinforcement Learning to generate problems with the desired properties. We conduct experiments on several classical domains, comparing our method with handcrafted domain-specific generators that generate valid and diverse problems but do not optimize difficulty. The results show NeSIG is able to automatically generate valid problems of greater difficulty than the competitor approaches, while maintaining good diversity

Decisiones estratégicas para aumentar la competitividad en el sector confecciones en el Valle de Aburrá

156 páginasEste trabajo de grado analiza la actualidad del sector Textil – Confecciones en el Valle de Aburrá y propone una estrategia que aumenta la competitividad del mismo. Primero se realizó un marco teórico que describe como se encuentra el entorno de las compañías del sector. Para esto se utilizaron modelos estratégicos de la teoría de la administración como las fuerzas de Porter y el ciclo de la industria. Una vez se contextualiza al lector, se procede al desarrollo del trabajo de grado. Para comenzar, se realizaron entrevistas a tres compañías del sector y a tres de sus clientes con el fin de entender las amenazas y oportunidades que estas enfrentan. Con la información provista por las compañías se sintetizaron las oportunidades y amenazas más importantes que afectan a las compañías, entre las cuales se encuentran los mercados internacionales y las eficiencias operativas para las oportunidades y el incremento del costo de la materia prima y la competencia desleal para las amenazas. Para realizar el análisis interno de fortalezas y debilidades, se seleccionó a la compañía Inversiones Marmol SAS. Se realizaron cuatro entrevistas a las personas encargadas de los procesos más importantes de la compañía incluyendo a la dirección, la producción y el área comercial. De acuerdo a la información recolectada en la compañía y a las entrevistas, se sintetizaron las fortalezas y las debilidades de la organización entre las cuales se encuentran la variedad del portafolio de productos como una fortaleza y la disponibilidad de productos como una debilidad. Con el análisis externo e interno del sector, se realizó una matriz DOFA para desarrollar estrategias con base a estos análisis. Estas estrategias se evaluaron posteriormente con base al impacto que podrían tener en la competitividad de la industria. Finalmente se estableció que la estrategia que debería implementar el sector para aumentar su competitividad sería la inversión en maquinaria, y más precisamente para la compañía analizada, la inversión en una nueva planta automática de estampación debido al incremento en la eficiencia que esta podría conllevar. Se creó un modelo financiero para evaluar la viabilidad financiera de la planta de estampación. Después de establecer las variables, los parámetros del modelo y sus supuestos, se descontaron los flujos del proyecto en un horizonte de inversión de 5 años. Como resultado, se obtuvo que la inversión es viable financieramente. Finalmente, se realizaron algunas recomendaciones para que las demás compañías del sector puedan adaptar este modelo y evaluar esta inversión de acuerdo a sus características.PregradoIngeniero(a) Administrativo(a

Quantitative phase determination by using a Michelson interferometer

The Michelson interferometer is one of the best established tools for quantitative interferometric measurements. It has been, and is still successfully used, not only for scientific purposes, but it is also introduced in undergraduate courses for qualitative demonstrations as well as for quantitative determination of several properties such as refractive index, wavelength, optical thickness, etc. Generally speaking, most of the measurements are carried out by determining phase distortions through the changes in the location and/or shape of the interference fringes. However, the extreme sensitivity of this tool, for which minimum deviations of the conditions of its branches can cause very large modifications in the fringe pattern, makes phase changes difficult to follow and measure. The purpose of this communication is to show that, under certain conditions, the sensitivity of the Michelson interferometer can be 'turned down' allowing the quantitative measurement of phase changes with relative ease. As an example we present how the angle (or, optionally, the refractive index) of a transparent standard optical wedge can be determined. Experimental results are shown and compared with the data provided by the manufacturer showing very good agreement.Fil: Pomarico, Juan Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil; Argentina. Universidad Nacional del Centro de la Provincia de Buenos Aires; ArgentinaFil: Molina, Pablo Fernando. Universidad Nacional del Centro de la Provincia de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil; ArgentinaFil: D'angelo, Cristian Adrián. Universidad Nacional del Centro de la Provincia de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil; Argentin

Análisis del leasing como una alternativa para la adquisición de computadores en la Alcaldía de Medellín para el período 2013-2015.

El presente trabajo parte de la necesidad que tiene la Alcaldía de Medellín de analizar mejores alternativas de inversión para realizar la reposición de los computadores que son utilizados por los servidores y servidoras de las diferentes Secretarías para el cumplimiento de la Misión Institucional. A su vez, identificar si a través de estas hay una oportunidad de obtener mayores beneficios los cuales se reflejarían en la administración eficiente de los recursos públicos. Se plantea el leasing operativo como una alternativa que permite acceder fácilmente a nuevas tecnologías sin comprometer capital de trabajo y con la facilidad de hacer renovación de los computadores cada 3 años minimizando el riesgo de obsolescencia, dado que esta modalidad de leasing es sin opción de compra, lo que significa que puede devolverlos al proveedor. En el trabajo se establecen tres alternativas para la compra de los computadores, las cuales se analizaron desde el punto de vista financiero partiendo del Estado de Resultados, luego se proyectaron los Flujos de Caja de Egresos para tres años teniendo en cuenta las particularidades en el manejo del Impuesto de Renta e IVA de una entidad pública como la Alcaldía de Medellín, además, de tener en cuenta que en este caso en las tres alternativas el beneficio que se genera para el Municipio de Medellín se verá reflejado en un menor gasto, es decir un ahorro que le permitiría realizar otro tipo de inversión a favor de la comunidad. Por último se trabajó con la metodología del valor presente, que se definió trayendo a precios de hoy los flujos de caja utilizando la inflación como tasa de descuento, para definir cuál será la opción más viable, que en este caso será la que requiera entregar menos flujo de caja.This paper relates to the necessity of The Medellin Municipality to analyze better investment alternatives for the renewal of computers that are used by public servants of the different secretariats to fulfill the Institutional Mission. Additionally, identify whether through these alternatives there is an opportunity to make more profits which would be reflected in the efficient management of public resources. Operating leasing is proposed as an alternative that allows easy access to new technologies without compromising working capital, and easy renewal of computers every 3 years, to minimize the risk of obsolescence, since this type of leasing has no purchase option, which means these can be returned to the supplier. Additionally, this paper sets out three options for the purchase of computers, which were analyzed from the financial perspective based on the earnings report; then Cash Flows from Operating Expenses were projected for three years, taking into consideration the peculiarities in the handling of the income tax and the value added tax of a public entity as the Medellin Municipality. In this sense, the benefit generated in the three alternatives for the Medellin Municipality will be reflected in lower expenses, i.e. savings that would allow other types of investment favoring the community. Finally, we worked with the NPV methodology, which was defined bringing the cash flows at today's prices, using the inflation as a discount rate, in order to define which will be the most viable option, which in this case will be the one that implies the less use of cash flows