Studies Using Computer Simulation Models to Solve Problems Related to Logistics Terminals

This thesis deals with the use of simulation as a problem-solving tool to solve a few logistic system related problems. More specifically it relates to studies on transport terminals. Transport terminals are key elements in the supply chains of industrial systems. One of the problems related to use of simulation is that of the multiplicity of models needed to study different problems. There is a need for development of methodologies related to conceptual modelling which will help reduce the number of models needed. Three different logistic terminal systems Viz. a railway yard, container terminal of apart and airport terminal were selected as cases for this study. The standard methodology for simulation development consisting of system study and data collection, conceptual model design, detailed model design and development, model verification and validation, experimentation, and analysis of results, reporting of finding were carried out. We found that models could be classified into tightly pre-scheduled, moderately pre-scheduled and unscheduled systems. Three types simulation models( called TYPE 1, TYPE 2 and TYPE 3) of various terminal operations were developed in the simulation package Extend. All models were of the type discrete-event simulation. Simulation models were successfully used to help solve strategic, tactical and operational problems related to three important logistic terminals as set in our objectives. From the point of contribution to conceptual modelling we have demonstrated that clubbing problems into operational, tactical and strategic and matching them with tightly pre-scheduled, moderately pre-scheduled and unscheduled systems is a good workable approach which reduces the number of models needed to study different terminal related problems.

Implicaciones de la adecuación del corredor intermodal Tumaco - Puerto Asís- Belem del Pará

Los resultados de esta investigación tienen como finalidad abrir los horizontes analíticos en el área del estudio de desarrollo regional, que frecuentemente no contempla la dimensión política, y la estructura conceptual y teórica del desarrollo sostenible además de ilustrar a organismos de carácter público o privado interesados en la materia que posean la capacidad de transformar este acercamiento académico y práctico a una realidad correcta. Para tal efecto en el primer capitulo se ubica y describe la zona geográfica de estudio, se realiza la justificación de los esfuerzos por adecuar esta vía de 8 comunicación en un corredor intermodal boiceánico, junto con una reseña de los hechos que dieron lugar al impulso político, social y económico de este proyecto. En el segundo capitulo se describe el marco político e institucional que da sustento político y económico al proyecto; el Server capítulo observa la dinámica y comportamiento de las actividades y circuitos productivos de la región. El cuarto capitulo valora el potencial de explotación y las posibles áreas en las cuales se desarrollarían proyectos de desarrollo sostenible. El quinto capitulo evaluará por medio del modelo de desarrollo sostenible los posibles impactos positivos de la adecuación de corredor intermodal Tumaco – Puerto Asís – Belém del Pará para el desarrollo sostenible de la región amazónica colombo brasileña.

Immunocytochemical characterization of the pregeniculate nucleus and distribution of retinal and neuropeptide Y terminals in the suprachiasmatic nucleus of the Cebus monkey

Circadian rhythms generated by the suprachiasmatic nucleus (SCN) are modulated by photic and non-photic stimuli. In rodents, direct photic stimuli reach the SCN mainly through the retinohypothalamic tract (RHT), whereas indirect photic stimuli are mainly conveyed by the geniculohypothalamic tract (GHT). In rodents, retinal cells form a pathway that reaches the intergeniculate leaflet (IGL) where they establish synapses with neurons that express neuropeptide Y (NPY), hence forming the GHT projecting to the SCN. In contrast to the RHT, which has been well described in primates, data regarding the presence or absence of the IGL and GHT in primates are contradictory. Some studies have suggested that an area of the pregeniculate nucleus (PGN) of primates might be homologous to the IGL of rodents, but additional anatomical and functional studies on primate species are necessary to confirm this hypothesis. Therefore, this study investigated the main histochemical characteristics of the PGN and the possible existence of the GHT in the SCN of the primate Cebus, comparing the distribution of NPY immunoreactivity, serotonin (5-HT) immunoreactivity and retinal terminal fibers in these two structures. The results show that a collection of cell bodies containing NPY and serotonergic immunoreactivity and retinal innervations are present within a zone that might be homologous to the IGL of rodents. The SCN also receives dense retinal innervations and we observed an atypical distribution of NPY- and 5-HT-immunoreactive fibers without regionalization in the ventral part of the nucleus as described for other species. These data may reflect morphological differences in the structures involved in the regulation of circadian rhythms among species and support the hypothesis that the GHT is present in some higher primates (diurnal animals). (C) 2009 Elsevier B.V. All rights reserved.

O transporte intermodal de cargas agrícolas e suas interfaces no Brasil

O objetivo do trabalho é analisar o transporte intermodal de cargas agrícolas e suas interfaces no Brasil. Devido ao grande numero de combinações possíveis, decidiu-se concentrar os estudos na movimentação de grãos, e dentro desta alternativa escolheu-se a soja que é o principal item da pauta de exportações agrícolas brasileira, superando o tradicional café (MRE (I) - Cacex), e o arroz que é o principal item de consumo alimentar no Brasil (MAA(2) - Ministério da Agricultura e do Abastecimento). Esta análise envolverá a movimentação dos produtos escolhidos para estudo, desde a fonte produtora, passando pela unidade de beneficiamento ou industrialização, até chegar ao seu ponto de entrega, incluindo: embalagem (quando o transporte não é for granel), modal de transporte utilizado, interfaces de transferência e armazenagem, quantidades movimentadas de cada produto típico e a pesquisa de custo porta-a-porta. Como conclusão será feita uma avaliação critica dos procedimentos logísticos encontrados e feitas sugestões para melhorar a qualidade e reduzir os custos totais nas movimentaçõesdas cargas estudadas

Immunocytochemical characterization of the pregeniculate nucleus and distribution of retinal and neuropeptide Y terminals in the suprachiasmatic nucleus of the Cebus monkey

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Bridging infrastructural gaps in Central America: prospects and potential for maritime transport

Includes bibliography

Mejores prácticas de transporte intermodal en las Américas: estudio de casos de exportaciones del MERCOSUR al NAFTA

Incluye Bibliografía

Identification of transmission line parameters from temporal measurements of currents and voltages in their terminals: Influence oh the length line

The objective of this paper is to show a methodology to estimate transmission line parameters. The method is applied in a single-phase transmission line using the method of least squares. In this method the longitudinal and transversal parameters of the line are obtained as a function of a set of measurements of currents and voltages (as well as their derivatives with respect to time) at the terminals of the line during the occurrence of a short-circuit phase-ground near the load. The method is based on the assumption that a transmission line can be represented by a single circuit π. The results show that the precision of the method depends on the length of the line, where it has a better performance for short lines and medium length. © 2012 IEEE.

Bothropstoxin-I reduces evoked acetylcholine release from rat motor nerve terminals: Radiochemical and real-time video-microscopy studies

Understanding the biological activity profile of the snake venom components is fundamental for improving the treatment of snakebite envenomings and may also contribute for the development of new potential therapeutic agents. In this work, we tested the effects of BthTX-I, a Lys49 PLA2 homologue from the Bothrops jararacussu snake venom. While this toxin induces conspicuous myonecrosis by a catalytically independent mechanism, a series of in vitro studies support the hypothesis that BthTX-I might also exert a neuromuscular blocking activity due to its ability to alter the integrity of muscle cell membranes. To gain insight into the mechanisms of this inhibitory neuromuscular effect, for the first time, the influence of BthTX-I on nerve-evoked ACh release was directly quantified by radiochemical and real-time video-microscopy methods. Our results show that the neuromuscular blockade produced by in vitro exposure to BthTX-I (1 μM) results from the summation of both pre- and postsynaptic effects. Modifications affecting the presynaptic apparatus were revealed by the significant reduction of nerve-evoked [3H]-ACh release; real-time measurements of transmitter exocytosis using the FM4-64 fluorescent dye fully supported radiochemical data. The postsynaptic effect of BthTX-I was characterized by typical histological alterations in the architecture of skeletal muscle fibers, increase in the outflow of the intracellular lactate dehydrogenase enzyme and progressive depolarization of the muscle resting membrane potential. In conclusion, these findings suggest that the neuromuscular blockade produced by BthTX-I results from transient depolarization of skeletal muscle fibers, consequent to its general membrane-destabilizing effect, and subsequent decrease of evoked ACh release from motor nerve terminals. © 2012 Elsevier Ltd.

Aspectos institucionales del transporte intermodal internacional: contribuciones de expertos latinoamericanos = Institutional aspects of international intermodal transport: contributions by Latin American experts

Incluye Bibliografía