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Ítem The effect of extrusion and drying on roller techniques concerning the rheological characteristics of rice-, corn-, sweet potato-, bean- and cassava root- and leaf- based composite flour(Universidad Nacional De Colombia, 2013-04-01) Combariza, AngélicaPromoting food security in Latin-America and the Caribbean is directly related to agricultural products. The region faces a food crisis which has reduced large population groups' access to food. This work contributes to the study of obtaining precooked composite flour made from biofortified crops using protein, vitamin A and/or minerals. This study evaluated the effect of precooked flour's com-position and precooking on its solubility in water, water absorption capacity, consistency and viscosity; such flour was obtained by extrusion and drying on rollers. The composite flours were obtained from cassava roots, sweet potato tubers, corn, rice and bean grains and cassava leaves. Four composite flours were formulated taking four- to six-year-old children's daily nutrient requirements (protein, iron, zinc and beta-carotenes) as a basis. The extruder was operated at 90oC, 300 rpm screw rotation speed, 17.64 g/min feed flow, with 30% moisture mixture. The dryer rollers were operated at 4 rpm roller rotation speed, 90oC surface temperature and 1 mm separation between rollers. It was determined that flour dried on rollers led to more complete cooking and modified starch granule structure than precooking by extrusion, thereby producing flour having greater solubility in water, less water absorption, higher consistency and smaller viscosity, comparable to that of pattern flour.Ítem Structural characterization and anti-aging activity of a novel extracellular polysaccharide from fungus Phellinus sp. in a mammalian system(Royal Society of Chemistry, 2016-08-01) Ma, Xiao-kuiLittle is known about the chemical structure of purified extracellular polysaccharides from Phellinus sp., a fungal species with known medicinal properties. A combination of IR spectroscopy, methylation analysis and NMR were performed for the structural analysis of a purified extracellular polysaccharide derived from Phellinus sp. culture, denoted as SHP-1, along with an evaluation of the anti-aging effect in vivo of the polysaccharide supplementation. The structure of SHP-1 was established, with a backbone composed of →2,4)-α-d-glucopyranose-(1→ and →2)-β-d-mannopyranose-(1→ and two terminal glucopyranose branches. Biochemical analysis from mammalian animal experiments demonstrated that SHP-1 possesses the ability to enhance antioxidant enzyme activities, such as catalase (CAT) and superoxide dismutase (SOD) activities, Trolox equivalent antioxidant capacity (TEAC) in serum of d-galactose-aged mice, while reducing lipofuscin levels, another indicator of cell aging, indicating a potential association with anti-aging activities in a dose dependent manner. This compound had a favourable influence on immune organ indices, and a marked amelioration ability of histopathological hepatic lesions such as necrosis, karyolysis and reduced inflammation and apoptosis in mouse hepatocytes. These results suggest that SHP-1 has strong antioxidant activities and a significant protective effect against oxidative stress or hepatotoxicity induced by d-galactose in mice and it could be developed as a food ingredient or a pharmaceutical to prevent many age-associated diseases such as major depressive disorder and hepatotoxicity. To our knowledge, this is the first report on the antioxidant effects of a novel purified exopolysaccharide derived from Phellinus sp. © 2016 The Royal Society of Chemistry.Ítem The micro-dynamics of queuing: understanding the formation of queues(Palgrave Macmillan Ltd., 2014-11-01) Delgado Álvarez, Carlos ArturoMost work in queuing theory is performed at an aggregate level, with linear models for which closed-form solutions can be derived. We are interested in creating a better understanding of how queues are formed by taking a bottom-up approach to their formation. We use a cellular automata framework to structure a set of agents who must choose which service facility to use. After using the facility, they update their expectations of sojourn time based on their own experience, and information received from their neighbours. On the basis of these updated expectations, they make their choice for the next period. We find that, after an initial transition period, customers mostly reach a quasi-stable situation, where the average sojourn time is close to the Nash equilibrium and social optimum, unless agents forget one of the facilities. We analyse different parameterizations of the agents' decision rules, and consider homogeneous and heterogeneous agent populations. © 2014 Operational Research Society Ltd.Ítem Heavy metals species affect fungal-bacterial synergism during the bioremediation of fluoranthene(Springer Verlag, 2016-08-01) Ma, XiaokuiThe co-occurrence of polycyclic aromatic hydrocarbons (PAHs) with heavy metals (HMs) is very common in contaminated soils, but the influence of HMs on fungal-bacterial synergism during PAH bioremediation has not been investigated. The bioremediation of fluoranthene-contaminated sand using co-cultures of Acremonium sp. P0997 and Bacillus subtilis showed increases of 109.4 and 9.8 % in degradation compared to pure bacterial and fungal cultures, respectively, removing 64.1 ± 1.4 % fluoanthene in total. The presence of Cu2+ reduced fluoranthene removal to 53.7 ± 1.7 %, while inhibiting bacterial growth, and reducing translocation of bacteria on fungal hyphae by 49.5 %, in terms of the bacterial translocation ratio. Cu2+ reduced bacterial diffusion by 46.8 and 31.9 %, as reflected by D (a bulk random motility diffusional coefficient) and Deff (the effective one-dimensional diffusion coefficient) compared to the control without HM supplementation, respectively. However, Mn2+ resulted in a 78.2 ± 1.9 % fluoranthene degradation, representing an increase of 21.9 %, while enhancing bacterial growth and bacterial translocation on fungal hyphae, showing a 12.0 % increase in translocation ratio, with no observable impact on D and Deff. Hence, the presence of HMs has been shown to affect fungal-bacterial synergism in PAH degradation, and this effect differs with HM species. © 2016, Springer-Verlag Berlin Heidelberg.Ítem Supply chain decision making: A system dynamics approach(Universidad Icesi, 2016-06-01) Arenas Guerrero, Fernando AntonioEste artículo presenta un análisis del impacto de los retrasos, el manejo de información y el tipo de demanda, en el desempeño de una cadena de abastecimiento de tres escalones, realizado con base en el “juego de la cerveza”. Se modelaron cuatro escenarios de acceso a información en la demanda final para varios miembros de la cadena usando dinámica de sistemas. Para cada uno de esos escenarios se realizaron cambios en los tiempos de retraso en la entrega y en el tipo de demanda; además, se usaron cuatro indicadores para medir el desempeño de la cadena de abastecimiento: el retorno sobre los activos, los ingresos acumulados, el valor de inventario acumulado y las inconformidades. Los resultados muestran que la localización (escalón) del acceso a la información es crítica para el desempeño y, en contraste con otros estudios, que este efecto es independiente del tipo de demanda. Los resultados obtenidos son consistentes con los de estudios previos, respecto del impacto positivo de la reducción de retrasos en el desempeño general de la cadena, sin importar el tipo de demanda.Ítem A decision support tool for healthcare providers to evaluate readiness and impacts of adopting supply chain data standards(Taylor & Francis, 2013-03-01) Burbano Collazos, AngélicaHealthcare providers are under increasing pressure to reduce waste, eliminate unnecessary costs and redundant efforts, thereby improving the quality and consistency of healthcare delivery. Lack of automation and the lack of use of global identifiers for products and locations, also known as supply chain data standards, are two critical factors that can help streamline providers operations and improve process efficiency. Despite widespread consensus among various stakeholders, healthcare providers lack a well-defined approach towards adopting and implementing data standards. Supply chain data standards can be defined as a set of product and location identifiers which are used in supply chain related processes and transactions.Ítem Simulation-optimization model for production planning in the blood supply chain(Springer Verlag, 2017-12-01) BrailsfordHonora K., Sally C.Production planning in the blood supply chain is a challenging task. Many complex factors such as uncertain supply and demand, blood group proportions, shelf life constraints and different collection and production methods have to be taken into account, and thus advanced methodologies are required for decision making. This paper presents an integrated simulation-optimization model to support both strategic and operational decisions in production planning. Discrete-event simulation is used to represent the flows through the supply chain, incorporating collection, production, storing and distribution.Ítem Asymptotic analysis of singular solutions of the scalar and mean curvature equations - Semantic Scholar(Hindawi Publishing Corporation, 2005-01-18) Yaker Agudelo, HendelWe show that positive solutions of a semilinear elliptic problem in the Sobolev critical exponent with Newmann conditions, related to conformal deformation of metrics in R n + , are asymptotically symmetric in a neighborhood of the origin. As a consequence, we prove for a related problem of conformal deformation of metrics in R n + that if a solution satisfies a Kazdan-Warner-type identity, then the conformal metric can be realized as a smooth metric on S n + .Ítem Measuring the impact of Lean tools on the cost–time investment of a product using cost–time profiles(Pergamon Press, Inc, 2007-12-01) Rivera Cadavid, LeonardoTraditional costing systems consider the accumulation of costs, but not their timing. Value stream mapping presents a good picture of the time consumed and operations performed for the production of a product within a manufacturing facility, but it does not track the accumulation of costs. The cost–time profile (CTP) is a tool that follows the accumulation of cost in the manufacturing of a product through time; and it finds the cost–time investment (CTI), which is an indicator of the use of resources in the manufacturing of a product through quantities and timing. In this paper, the expected impact of Lean implementations on the CTP and CTI is discussed. The CTP is proposed as a useful tool for the evaluation of the improvements achieved by the implementation of Lean tools and techniques.Ítem Beyond Partnerships: The Power Of Lean Supply Chains(Springer London, 2007-01-01) Chen, F. FrankExtending the value stream from a lean company to its partners allows the company to widen the pursuit for perfection to the whole supply network. Furthermore, applying lean concepts to a supply chain opens new windows of opportunity for supply chain participants to collectively achieve higher levels of competitiveness. Thus, the integration of supply chain management and lean thinking covers both local and overall leanness, which leads to a truly lean supply chain. This chapter provides an overview of the lean supply chain, the including concepts, approaches, challenges, and future development. In the first part of the chapter, basic concepts and impacts of lean thinking will be introduced, followed by the issues of applying lean thinking in supply chain management. Then, an integrated framework of a lean supply chain will be presented. The second part of the chapter covers the building blocks of lean supply chains, including lean logistics, information technology, performance measurement and improvement, and collaboration beyond partnerships. Subsequently, the challenges for building or maintaining a sustainable lean supply chain will be discussed.Ítem El WIP como objetivo estratégico en la distribución de planta(Universidad Santiago de Cali, 2012-01-01) Cardona, Luis FelipeThis paper presents a model to generate the layout of a facility, minimizing the work in process (WIP) for a production system that uses multiple material handling systems. Using WIP as an objective in a facility layout problem is a novel approach. WIP is an operating performance measure that impacts directly in the production costs, and is generally not considered in facility layout problems. As a result, we present a model to design facility layouts with a better WIP performance than the ones designed by a model with a single material handling systemÍtem Applying systems thinking and active learning strategies to a lean manufacturing program(Proceedings Of The 21st Annual Conference Of The Production And Operations Management Society, 2010-05-07) Rivera Cadavid, LeonardoLean Manufacturing seeks to eradicat e waste. This pursuit is conducted changing many pre-conceptions inherited fr om the mass production traditions. It is necessary to understand immediate and delayed impacts of the changes, as well as direct and indirect results of these changes. Th is systemic approach should enhance the learner’s understanding of the system (the manufacturing company) , its variables, its outcomes, and the relationships among the system’s components. This paper presents the process of designing a course to teach Lean Manufacturing to working professionals using systems thinking. This design proce ss is conducted for the development of job competencies and using Active Learning Strategies.Ítem Financial risk assessment of different inventory policies(Escuela de ingenieria de Antioquia, 2011-12-01) Toro, Héctor HernánEste trabajo se concentra en la evaluación de los efectos económicos asociados a diferentes políticas de inventario. Se estudia el valor en riesgo del valor de una compañía, además de las variaciones inducidas por los cambios en el capital de trabajo asociados a diferentes políticas de inventario. Se estudian tres sistemas de inventario y se comparan diferentes políticas. Se contrastan las políticas derivadas de la maximización del valor presente neto (VPN) contra la minimización de costos y contra políticas de inventario arbitrarias derivadas de las condiciones de mercado. Para cada sistema de inventario se estiman dos indicadores de desempeño: VPN y VaR del VPN. Las políticas de inventario se construyeron en un escenario de certeza, pero se evalúan incorporando diferentes condiciones de riesgo, para lo cual se utiliza simulación de Monte Carlo. Las conclusiones se obtienen a partir del desempeño observado en diferentes casos de estudio, usando ambos indicadores. En los tres sistemas de inventario bajo estudio, la diferencia entre precio y costo variable es lo que causa la mayor variación en el indicador del VPN. Un resultado importante de este trabajo es que para los casos estudiados, más bien comunes en el mundo real, las políticas de inventario óptimo obtenidas por minimización de costos son, desde la perspectiva de la minimización de riesgo, tan buenas como las obtenidas mediante maximización del beneficio.Ítem Evaluation of the Reliability of a Water Supply Network from Right-Censored and Left-Truncated Break Data(Springer Netherlands, 2010-09-01) Gamiz, María LuzIn this paper, we analyze failure data registered in a water supply network in order to evaluate the pipes failure probability. Only failures in normal operation conditions have been considered, excluding those caused by abnormal events. We consider an observation window from year 2000 until 2005, although the life of some of the water pipes started far in the past. This sampling scheme induces left-truncation into the data set (since failures before 2000 are not considered into the sample information) and right-censoring (for pipes that fail after 2005). We used an extended version of the Nelson–Aalen estimator, modified in order to accommodate left-truncation besides right-censoring (LTRC). Influencing factors on water pipes survival are identified. By the use of a semiparametric model based on the Cox proportional hazards model, also adapted to manage left-truncated and right-censored data, the effect of each factor over the failure risk of a pipe section has been estimated.Ítem Analytical study of the Fishbone Warehouse layout(Taylor & Francis, 2012-11-19) Rivera Cadavid, LeonardoThe purpose of this paper is to study the Fishbone Warehouse layout. Fishbone layouts are non-traditional designs for warehouses that have shown to be more efficient under unit-load operations. This paper presents an analytical study of the design from an optimisation point of view. The authors gain an insight into the characteristics of the layout and present alternatives for different situations of interest in industrial environments. Finally, the authors compare the performance of Fishbone and traditional designs; presenting a formal conception of the expected savings. The authors focus on finding optimal conditions for the most important characteristic of the Fishbone design, which is the slope of the diagonal cross-aisle. The design decisions are modelled as a non-linear optimisation problem and solved using both numerical and exact methods, depending on the most convenient analysis. In addition, the robustness of the results is presented and their practical implications discussed.Ítem A structured review of quantitative models in the blood supply chain: a taxonomic framework for decision making(Taylor & Francis, 2015-12-17) Osorio Muriel, Andrés FelipeThis paper presents a structured review of the literature on quantitative modelling for the blood product supply chain. This is a widely-researched topic, dating back to the 1960s, and several other reviews have been published over the years. However, this paper presents new relevant information for researchers, not only by including more recent models but chiefly because of the structured way in which the models are presented. The models are broken down into five categories. The first four categories represent the four stages (echelons) in the supply chain: collection, production, inventory, and delivery. The final category contains “integrated” models which cover more than one stage. Each section (other than integrated models, which are treated slightly differently) contains two distinct elements. The first element is a diagrammatic representation of decisions and relationships, broken down by hierarchy level (strategic – tactical – operational). The second element is a text description of the main features, contributions and gaps found in the analysed models. An additional element for each section is available online, namely a searchable table describing specific features of each echelon, together with a taxonomic key to assist the reader.Ítem An MIP model to optimize a Colombian cash supply chain(Wiley, 2012-04-01) Osorio Muriel, Andrés FelipeFinancial institutions operate a supply chain where only one product is moved across the network. Although the cash is kept in several nodes to service the demand of final customers, availability causes opportunity cost related with its investment options. When planning the inventory of cash that should be maintained across the network, transportation decisions are also expected to be made. Cash transportation has a high cost, associated with the high risk of theft. Increasing the inventory can reduce the need for transportation, but the opportunity cost can be very high. Moreover, the inventory is also related with the service level perceived for final customers; therefore because of low inventory some people are not able to make some transactions. The aim of this work is to find optimal decisions related with cash inventory and transportation across the network, trying to balance the cost of the service and the quality perceived for final users.Ítem Application of macroergonomics principles in the implementation of computer integrated manufacturing systems(Universidad del Valle, 2013-10-18) Rivera Cadavid, LeonardoMuchas implementaciones de Sistemas de Manufactura Integrada por Computador (CIMS, por sus siglas en Inglés) han estado plagadas de fallas e imprevistos. En algunos casos se han identificado como causa raíz de estas fallas el desconocimiento y la no consideración de las dimensiones humanas y organizacionales de un cambio técnico de gran escala. En este artículo se utilice el Análisis y Diseño Macroergonómico (MEAD, su sigla en Inglés) como un marco de referencia para reconocer de manera implícita estos factores y considerarlos desde las fases de diseño de un nuevo sistema de trabajo.Ítem Justificación conceptual de un modelo de implementación de Lean Manufacturing(Universidad del Valle, 2013-10-19) Rivera Cadavid, LeonardoEn los últimos 20 años se han discutido diferentes técnicas que hacen parte de Lean Manufacturing en la literatura gerencial, en presentaciones y conferencias y en ofertas de consultoría. En muchos casos esta presentación de técnicas se ha hecho sin proponer un modelo de implementación que permita la evolución de la empresa en un camino de mejoramiento, y que subraye qué técnicas y principios deberían implementarse antes que otras. En el presente artículo se presenta una estructura de prerrequisitos para la implementación de Lean Manufacturing y sus técnicas, y se discute la lógica y validez conceptual de dicha estructura.Ítem A Novel GS1 Data Standard Adoption Roadmap for Healthcare Providers(IGI Global, 2011-01-01) Burbano Collazos, AngélicaThe use of GS1 Data Standards is envisioned to improve the efficiency of the healthcare supply chain as it did for the retail supply chain. The healthcare industry, especially providers, acknowledges their potentials; however, there are misconceptions and lack of understanding the associated costs and expected benefits. This study presents an adoption roadmap for GS1 Data Standards at the provider level in healthcare industry. The developed roadmap is a result of systematic efforts at conducting extensive studies, examining the best practices, and interacting with industry leaders. The adoption roadmap includes different levels and sublevels to provide a flexible foundation for healthcare providers where alternative adoption paths will be available for their immediate needs and requirements. Sublevels have a recommended precedence structure to realize maximum gains from the adoptions. The feasibility and practicality of the developed roadmap has been validated by two pilot studies, which were conducted in collaboration with two hospital provider partners. The pilot studies helped identify potential benefits as well as roadblocks and barriers for different levels of GS1 Data Standards adoption. The results indicate that the adoption is not an easy process and may require many workarounds; however, the potential gains are significant.