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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
131

Ajuste de curvas de crescimento e deposição de nutrientes em linhagens de frangos de corte com análise econômica / Growth curves adjustment and nutrient deposition in broilers strains with economic analysis

Leandro Félix Demuner 24 August 2016 (has links)
O estudo foi conduzido para estimar os parâmetros, avaliar e comparar os ajustes de curvas de crescimento corporal e dos componentes corporais físicos e químicos, de linhagens de frangos de corte sexados. Foram utilizados 1848 pintinhos de um dia de idade distribuídos em delineamento inteiramente casualizado com tratamentos em esquema fatorial hierárquico com os fatores: Sexo (Macho e Fêmea) e Linhagens (Cobb 500, Ross 308 e Hubbard Flex) dentro de cada sexo, totalizando seis tratamentos com seis repetições de 50 aves cada. A dieta experimental atendeu à necessidade nutricional para cada sexo. No primeiro dia foram abatidos oito animais de cada linhagem e sexo, obtendo o peso inicial dos componentes físicos e químicos e semanalmente as aves e rações de cada boxe foram pesadas para obter os dados de consumo de ração e peso corporal. De acordo com o peso médio de cada boxe foram feitos abates semanais, de dois a três animais (24h de jejum), sendo obtidos os pesos: corporal em jejum, corporal em jejum depenado, penas, carcaça, peito, coxa, sobrecoxa, asa, coração, fígado e moela. Outras duas aves (a partir do peso médio do boxe) em jejum foram foram selecionadas para o estudo de deposição dos nutrientes sobre o peso corporal em jejum depenado e de penas, tendo amostras destas características sido processadas, homogeneizadas e analisadas para matéria seca, nitrogênio, extrato etéreo e cinzas. Os parâmetros médios das curvas foram estimados, assim como os coeficientes alométricos e utilizados os critérios estatísticos de qualidade de ajuste (coeficiente de determinação, coeficiente de determinação ajustado, Critério de informação de Akaike e Critério de informação Bayesiano de Schwarz) para selecionar o modelo mais adequado. Também foi realizada a análise técnica (conversão alimentar) e econômica (margem bruta de comercialização -MB) a partir de estimativas de pesos corporais e de consumo de ração do melhor modelo selecionado, nos pesos e idade de abate predeterminados. A curva de Gompertz e a equação de alometria em função da proteína corporal foram selecionadas para estimar os valores individuais dos pesos de cada boxe e avaliar os efeitos de sexo e de linhagem em cada sexo. Os coeficientes alométricos foram heterogônicos negativos para a deposição de água corporal e órgãos; e heterogônicos positivos para cinzas, gordura corporal, carcaça e cortes da carcaça. Os machos tiveram maior desenvolvimento corporal e dos componentes com maior precocidade, exceto para gordura corporal. Macho Cobb 500 apresentou peso superior de peito; macho Hubbard maior deposição de proteína corporal, sendo mais eficiente tecnicamente e Ross 308, macho e fêmea, foram mais precoces para crescimento corporal e para a maior parte dos componentes. Na análise econômica utilizando o modelo Gompertz observou-se que machos apresentaram melhor conversão alimentar e MB do que fêmeas e Ross 308, apesar de ter comportamento superior em crescimento e precocidade, não foi tão eficiente tecnicamente e/ou economicamente quanto às linhagens Cobb 500 e Hubbard Flex nas últimas pesagens. / The study was conducted to estimate the parameters, evaluate and compare the adjustments of body growth curves and the physical and chemical body components, lines of sexed broilers. 1848 day-old chicks in a completely randomized design in a factorial design with treatments in hierarchical factorial design with the factors: sex (male and female) and strains (Cobb 500, Ross 308 and Hubbard Flex) within each sex, a total of six treatments with six replicates of 50 birds each. The experimental diet attended the nutritional requirement for each sex. On the first day, eight animals of each strain and sex were slaughtered, obtaining the initial weight of the physical and chemical components and weekly birds and every boxing feeds were weighed for the feed intake data and body weight. According to the mean weight of each pen were made weekly slaughter, two or three animals (24 h of fasting) were obtained, weights: Body fasting, body fasting plucking, feathers, carcass, chest, thigh, drumstick, wing, heart, liver and gizzard. Other two birds (from average body weight) fasted were used to study deposition of nutrients on body weight plucking fasting and feathers, and samples of these characteristics were processed, homogenized and analyzed for dry matter, nitrogen, extract ethereal and ashes. The average curve parameters were estimated, as well as the allometric coefficients and used statistical criteria for goodness of fit (coefficient of determination, adjusted determination coefficient, Akaike information criterion and Bayesian information criterion of Schwarz) to select the most appropriate model. It was also carried out technical analysis (feed conversion) and economic (gross margin trading -GM) from body weights estimates and feed intake of the best model selected, the weight and age of predetermined slaughter. The Gompertz curve and the allometry equation as a function of body protein were selected to estimate individual values of each pen weights and evaluate the effects of sex and strain of each sex. The allometric coefficients were negative heterogônic for the deposition of body water and organs; and positive heterogônic for ashes, body fat, carcass and carcass cuts. Males had earlier higher body development and their components, except for body fat. Male Cobb 500 showed a higher weight breast and thigh, male Hubbard had greater deposition of body protein being more efficient and technically Ross 308, male and female, were earlier for body growth and most of their components. In the economic analysis using the Gompertz model it was observed that males had better feed conversion and GM than females and Ross strain 308, despite having higher growth and precocity, it was not as efficient technically and / or economically as the Cobb 500 and Hubbard Flex. Males had higher body development and components begin earlier, except for body fat. Male Cobb 500 showed superior weight breast; Male Hubbard had greater deposition of body protein being more efficient and technically Ross 308, male and female, were earlier for body growth and most of the components. In the economic analysis using the Gompertz model was observed that males had better feed conversion and MB than females and Ross strain 308, that despite having superior behavior on growth and earliness, this last line was not as efficient technically and / or economically as the lines Cobb 500 and Hubbard Flex in the last weighing.
132

Maximização da produção em uma fábrica de sorvetes utilizando uma abordagem integrada de dimensionamento e sequenciamento de lotes /

Thomazella Netto, Rodrigo. January 2018 (has links)
Orientador: Fernando Bernardi de Souza / Coorientadora: Sônia Cristina Poltroniere Silva / Banca: Roberto Fernandes Tavares Neto / Banca: Adriana Cristina Cherri Nicola / Resumo: O presente estudo visa maximizar a produção do processo mais restritivo em uma fábrica de sorvetes, aplicando uma adaptação do modelo de otimização matemática GLSPST (General Lot sizing and Sequence dependent Setup Times). Esse modelo trata da integração de problemas de dimensionamento de lote e programação de produção com o tempo de configuração, dependendo da sequência. A fábrica estudada enfrenta problemas que atendem suas demandas, estoques elevados para determinados produtos e nenhum estoque para outros, além de fazer muitas configurações devido a mudanças de sabor. Adaptações de acordo com as particularidades da empresa estudada foram realizadas utilizando o modelo GLSPST e, além disso, como o objetivo do estudo é maximizar a produção do recurso com restrição de capacidade, e não minimizar custos, houve uma mudança função objetivo. Os resultados dos testes em diferentes classes e configurações detalhadas são apresentados. O modelo foi executado usando o software CPLEX 12.6 / Abstract: The present study aims to maximize the production of the most restrictive process in an ice cream factory by applying an adaptation of the mathematical optimization model GLSPST (General Lot sizing and Sequence dependent Setup Times). This model deals with the integration of lot sizing and production scheduling problems with setup time, depending on the sequence. The factory studied faces problems meeting its demands, high stocks for certain products and no stock for others, in addition to making many setups due to flavor changes. Adaptations according to the particularities of the company studied were performed using the GLSPST model and, in addition, since the objective of the study is to maximize the production of the resource with capacity constraint, and not minimize costs, a change was made in the objective function. The results of the tests in different classes and detailed settings are presented. The model was run using CPLEX 12.6 software / Mestre
133

A Singular Perturbation Approach to the Fitzhugh-Nagumo PDE for Modeling Cardiac Action Potentials.

Brooks, Jeremy 01 May 2011 (has links)
The study of cardiac action potentials has many medical applications. Dr. Dennis Noble first used mathematical models to study cardiac action potentials in the 1960s. We begin our study of cardiac action potentials with one form of the Fitzhugh-Nagumo partial differential equation. We use the non-classical method to produce a closed form solution for the decoupled Fitzhugh Nagumo equation. Using voltage recording data of action potentials in a cardiac myocyte and in purkinje fibers, we estimate parameter values for the closed form solution with standard linear and non-linear regression methods. Results are limited, thus leading us to perturb the solution to obtain a better fit. We turn to singular perturbation theory to justify our pole-based approach. Finally, we test our model on independent action potential data sets to evaluate our model and to draw conclusions on how our model can be applied.
134

Evaluation of the Supply Chain of Key Industrial Sectors and its Impact on the Electricity Demand for a Regional Distribution Company

Mariotoni, Thiago Arruda 18 September 2007 (has links)
Considering the international scenario, in a recent past, the electrical industry was based on the concepts of monopolistic concessions and vertical utilities structures. In Brazil, until recently, the electricity companies were all governmental properties that served restricted monopolized areas. In a similar manner, in the United States, monopolies for certain concession areas were assigned to vertically integrated electric utilities. This monopolistic portfolio brought to the industry, in a generic sense, a lack in the interface between companies and consumers. This fact established a low capacity of obtaining consumer's information and consequently, a low capacity of developing precise demand forecasts. Lately, the industry of electrical energy around the world has passed through immense structural changes, not only in developed countries, but also in developing countries. In this new environment, competition and private capital are fundamental agents. Now, demand forecasting represents a key factor to support decision-making for planning strategies of electricity utilities. In addition to immediate potential benefits to commercial decisions, a framework for electricity demand forecasting can help to take actions aiming to develop more precise yearly budgets as well as to make accurate investments in the infrastructure expansion. With the objective of improving the supply chain perception of the electricity industry, this work analyzes the electricity industry and develops a mathematical tool to accurately support the decision-making process of electricity utilities. CPFL Energy Co., a holding that controls companies and private enterprises in the generation area, electric power distribution, and trading in Brazil, was chosen as the case of study. CPFL Energy Co.'s supply chain was studied to find out the right explanatory variables and an electricity forecasting mathematical model was created through the stepwise regression procedure.
135

Optimal Control Theory and Estimation of Parameters in a Differential Equation Model for Patients with Lupus

Agaba, Peter 01 April 2019 (has links)
System Lupus Erythematosus (SLE) is a chronic inflammatory autoimmune disorder that affects many parts of the body including skin, joints, kidneys, brains and other organs. Lupus Nephritis (LN) is a disease caused by SLE. Given the complexity of LN, we establish an optimal treatment strategy based on a previously developed mathematical model.For our thesis work, the model variables are: Immune Complexes (I), Pro-inflammatory mediators (P), Damaged tissue (D), and Anti-inflammatory mediators (A). The analysis in this research project focuses on analyzing therapeutic strategies to control damage using both parameter estimation techniques (integration of data to quantify any uncertainties associated with parameters) and optimal control with the goal of minimizing time spent on therapy for treating damaged tissue by LN.
136

Pharmacokinetic and Pharmacodynamic Evaluation of Cocaine Hydrolases for the Treatment of Cocaine Overdose and Cocaine Addiction Using Rodent Models

Zheng, Xirong 01 January 2019 (has links)
Overdose and addiction are two medical complications of cocaine abuse. To date, there is no FDA approved pharmacotherapy specific for cocaine abuse. Cocaine hydrolases (CocHs) have been extensively investigated for its potential in anti-cocaine therapy. Previous studies have demonstrated that CocHs efficiently hydrolyze cocaine to generate biologically inactive metabolites both in vivo and in vitro. However, it has not been studied whether there is gender difference in the therapy using CocHs. In addition, the effectiveness of CocHs is unknown for treating cocaine toxicity when alcohol is co-administered. The main purpose of this dissertation is to characterize and evaluate efficient CocHs for cocaine overdose and cocaine addiction treatment. In the first set of studies, the effectiveness of human serum albumin-fused CocH1 were studied in male and female rats. The pharmacokinetic profiles, as well as the pharmacodynamic effects of CocH1-HSA were compared in male and female rats. The obtained data clearly demonstrated that CocH1-HSA was equally effective in both genders. The second set of studies investigated the efficiency of Fc-fused CocH5 in reversing cocaine toxicity in rats receiving simultaneous administration of cocaine and alcohol. Results showed that CocH5-Fc rapidly hydrolyzed cocaine and cocaine’s toxic metabolites in rats, and demonstrated that CocH5-Fc was efficient in treating cocaine toxicity when alcohol was simultaneously administered. In later studies to investigate the effects of CocH5-Fc for the treatment of cocaine addiction, a mathematical model was developed and validated to predict the effects of CocH5-Fc on the disposition of cocaine in rat blood and brain. This model adequately described the effects of CocH5-Fc in accelerating the elimination of cocaine and its toxic metabolites in both rat blood and brain. In conclusion, the studies within the current dissertation demonstrate the clinical potential of CocHs for the treatment of both cocaine overdose and cocaine addiction.
137

BIO-MATHEMATICS: INTRODUCTION TO THE MATHEMATICAL MODEL OF THE HEPATITIS C VIRUS

Durfee, Lucille J 01 December 2016 (has links)
In this thesis, we will study bio-mathematics. We will introduce differential equations, biological applications, and simulations with emphasis in molecular events. One of the first courses of action is to introduce and construct a mathematical model of our biological element. The biological element of study is the Hepatitis C virus. The idea in creating a mathematical model is to approach the biological element in small steps. We will first introduce a block (schematic) diagram of the element, create differential equations that define the diagram, convert the dimensional equations to non-dimensional equations, reduce the number of parameters, identify the important parameters, and analyze the results. These results will tell us which variables must be adjusted to prevent the Hepatitis C virus from becoming chronic.
138

Modeling caveolar sodium current contributions to cardiac electrophysiology and arrhythmogenesis

Besse, Ian Matthew 01 May 2010 (has links)
Proper heart function results from the periodic execution of a series of coordinated interdependent mechanical, chemical, and electrical processes within the cardiac tissue. Central to these processes is the action potential - the electrochemical event that initiates contraction of the individual cardiac myocytes. Many models of the cardiac action potential exist with varying levels of complexity, but none account for the electrophysiological role played by caveolae - small invaginations of the cardiac cell plasma membrane. Recent electrophysiological studies regarding these microdomains reveal that cardiac caveolae function as reservoirs of 'recruitable' sodium ion channels. As such, caveolar channels constitute a substantial and previously unrecognized source of sodium current that can significantly influence action potential morphology. In this thesis, I formulate and analyze new models of cardiac action potential which account for these caveolar sodium currents and provide a computational venue in which to develop and test new hypotheses. My results provide insight into the role played by caveolar ionic currents in regulating the electrodynamics of cardiac myocytes and suggest that in certain pathological cases, caveolae may play an arrhythmogenic role.
139

Yeast metabolism in fresh and frozen dough : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Food Technology at Massey University, Palmerston North, New Zealand

Miller, Simon Derek Unknown Date (has links)
Author also know as S M Loveday / Fresh bakery products have a very short shelf life, which limits the extent to which manufacturing can be centralised. Frozen doughs are relatively stable and can be manufactured in large volumes, distributed and baked on-demand at the point of sale or consumption. With appropriate formulation and processing a shelf life of several months can be achieved.Shelf life is limited by a decline in proofing rate after thawing, which is attributed to a) the dough losing its ability to retain gas and b) insufficient gas production, i.e. yeast activity. The loss of shelf life is accelerated by delays between mixing and freezing, which allow yeast cells the chance to ferment carbohydrates.This work examined the reasons for insufficient gas production after thawing frozen dough and the effect of pre-freezing fermentation on shelf life. Literature data on yeast metabolite dynamics in fermenting dough were incomplete. In particular there were few data on the accumulation of ethanol, a major fermentation end product which can be injurious to yeast.Doughs were prepared in a domestic breadmaker using compressed yeast from a local manufacturer and analysed for glucose, fructose, sucrose, maltose and ethanol. Gas production after thawing declined within 48 hours of frozen storage. This was accelerated by 30 or 90 minutes of fermentation at 30;C prior to freezing.Sucrose was rapidly hydrolysed and yeast consumed glucose in preference to fructose. Maltose was not consumed while other sugars remained. Ethanol, accumulated from consumption of glucose and fructose, was produced in approximately equal amounts to CO2, indicating that yeast cells metabolised reductively.Glucose uptake in fermenting dough followed simple hyperbolic kinetics and fructose uptake was competitively inhibited by glucose. Mathematical modelling indicated that diffusion of sugars and ethanol in dough occurred quickly enough to eliminate solute gradients brought about by yeast metabolism.
140

Modelling Chemical Communication in Neuroglia

Edwards, James Roy January 2007 (has links)
Master of Science / In vivo many forms of glia utilise both intercellular and extracellular pathways in the form of IP3 permeable gap junctions and cytoplasmic ATP diffusion to produce calcium waves. We introduce a model of ATP and Ca2+ waves in clusters of glial cells in which both pathways are included. Through demonstrations of its capacity to replicate the results of existing theoretical models of individual pathways and to simulate experimental observations of retinal glia the validity of the model is confirmed. Characteristics of the waves resulting from the inclusion of both pathways are identified and described.

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