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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.
111

Desenvolvimento de métodos analíticos para avaliação da presença de elementos essenciais e potencialmente tóxicos em fórmulas infantis

Gamela, Raimundo Rafael January 2017 (has links)
O consumo de fórmulas infantis no Brasil, utilizadas como substituto do leite materno, tem aumentado nos últimos anos de forma significativa. Tal fato é uma preocupação para os órgãos de saúde pois, o aleitamento materno exclusivo até no mínimo 6 meses, deixou de fazer parte de nutrição da maioria dos lactentes. Os produtos utilizados como substituto do leite materno contêm quantidades suficientes de vitaminas e nutrientes que ajudam no desenvolvimento normal do organismo dos lactentes. Entretanto, além de elementos essenciais, podem conter elementos potencialmente tóxicos presentes na matéria prima ou oriundos das etapas de processamento e armazenamento das mesmas. No presente trabalho foram desenvolvidos métodos analítico para determinar a presença de elementos potencialmente tóxicos (As, Cd, Pb e Tl) e essenciais (Cu e Mn) em fórmulas infantis, utilizando espectrometria de absorção atômica de alta resolução com fonte contínua e forno de grafite e análise direta de sólidos. As amostras utilizadas neste trabalho foram obtidas nos mercados da cidade de Porto Alegre, RS, Brasil, todas na forma sólida (pó) com diferentes composições e matéria prima (arroz, aveia, soja e leite). As curvas de calibração foram realizadas com soluções padrão aquosas e os métodos otimizados foram aplicados nas amostras em estudo. Em todas as amostras os elementos As, Cd, Pb e Tl apresentaram valores de concentração abaixo do limite de detecção. Das seis amostras analisadas, três apresentaram valores de concentração de Cu abaixo dos parâmetros mínimos estabelecidos pela legislação brasileira, enquanto que para o Mn todas amostras apresentaram valores de concentração dentro dos parâmetros mínimos da legislação brasileira. Os métodos desenvolvidos foram simples, exatos e precisos, podendo ser utilizados para análise de rotina. / The consumption of infant formula in Brazil, as a replacement of breast milk, has lately increased significantly. It is a major concern for health agencies because the exclusive breastfeeding up to at least 6 months is no longer part of most infants. The products used as a substitute of the breast milk contain sufficient amounts of vitamins and nutrients, which helps in the normal development of the infants. However, besides the essential elements, it may contain potentially toxic elements present in raw material or from of the processing and storage stages of the same. In the present work the presence of the essential (Cu e Mn) and potentially toxic elements (As, Cd, Pb e Tl) in infant formulas were evaluated. For this, analytical methods were developed for the determination of As, Cd, Cu, Mn, Pb and Tl using high-resolution continnum source graphite furnace atomic absorption spectrometry and direct solid sampling analysis in infant formulas. The samples were acquired in Porto Alegre’s market, RS, Brazil, all in powder form with different compositions and raw materials (rice, oats, soy and bovine milk). The calibration curves were performed with aqueous standard solutions and the optimized methods were applied in the study samples. In all samples, the concentration values of As, Pb, Cd and Tl were below of the limit of detection. For the analyzed samples, three of them present the concentration values of Cu lower than the minimum parameters established by Brazilian legislation, while for Mn, all samples present the concentration values within the minimum parameters of Brazilian legislation. The developed methods for the determination of these elements in infant formulas were simple, exacts and precise, and can be applicated for the routine analysis.
112

Fatores associados ao aleitamento materno e ao consumo de leite de vaca e fórmula infantil de lactentes atendidos em unidades básicas de saúde / Factors associated with breastfeeding and the consumption of cow's milk and infant formula in infants attending at primary health care

Souza, Ludimila Pereira da Silva 27 February 2015 (has links)
Submitted by Cássia Santos (cassia.bcufg@gmail.com) on 2015-10-21T12:41:45Z No. of bitstreams: 2 Dissertação -Ludimila Pereira da Silva Souza - 2015.pdf: 1303469 bytes, checksum: b364a318b441043e6cc435d82ad0a1f2 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2015-10-22T12:58:40Z (GMT) No. of bitstreams: 2 Dissertação -Ludimila Pereira da Silva Souza - 2015.pdf: 1303469 bytes, checksum: b364a318b441043e6cc435d82ad0a1f2 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2015-10-22T12:58:40Z (GMT). No. of bitstreams: 2 Dissertação -Ludimila Pereira da Silva Souza - 2015.pdf: 1303469 bytes, checksum: b364a318b441043e6cc435d82ad0a1f2 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2015-02-27 / The objective the present study was to evaluate the factors associated with breastfeeding, and consumption of cow's milk and infant formula. This is a cross-sectional study, from a matrix study ENFAC, with 213 children between 12 to 15 months. Milk consumption was evaluated using R24h. We analyzed the association of the independent variables with the outcomes breastfeeding, consumption of cow's milk and consumption of infant formula. The infants were categorized in three groups: breastfeeding (BF), complemented breastfeeding (CBF) and not breastfeeding (NBF). The mean intake of macronutrients and calcium adjusted for energy, and average month weight and length gain was compared among groups. It was observed that 50.2% of the children were breastfed and 56.1% of breastfed children consumed another milk. There was a negative association between maternal education and consumption of cow´s milk (p = 0.046), however positive association with the amount of milk ingested for infants (p = 0.005). Energy intake of the CBF group was higher than the BF and NBF (p < 0.001). Moreover, the CBF group showed average month weight gain greater than BF (p = 0.017). Calcium intake was higher in the NBF group (p < 0.001). It was concluded that half of the infants consumed breast milk and it was found a high consumption of other milks for breast-fed infants. Children of mothers with a lower level of education consumed cow's milk more often; however, the amount ingested was lower. Those in complemented breastfeeding presented higher energy consumption and greater weight gain. / O objetivo desse estudo foi avaliar os fatores associados ao aleitamento materno e ao consumo de leite de vaca e fórmula infantil. Trata-se de estudo transversal, parte do estudo matriz ENFAC, com 213 crianças entre 12 a 15 meses. O consumo de leite foi avaliado pelo R24h. Analisou-se a associação das variáveis independentes com os desfechos aleitamento materno, consumo de leite de vaca e consumo de fórmula infantil. Os lactentes foram categorizados em três grupos: aleitamento materno (AM), aleitamento materno complementado (AMC) e não estava em aleitamento materno (NAM). As médias do consumo de macronutrientes e cálcio ajustados pela energia, e do ganho de peso e do comprimento médio foram comparadas entre os grupos. Observou-se que 50,2% das crianças eram amamentadas e 56,1% delas consumiram outro leite. A escolaridade materna apresentou associação negativa com a frequência do consumo de leite de vaca (p = 0,046), porém associação positiva com a quantidade ingerida desse leite pelos lactentes (p = 0,005). O consumo energético do grupo AMC foi maior que do AM e NAM (p < 0,001). Ainda, o grupo AMC apresentou ganho de peso mensal maior que o AM (p = 0,017). O consumo de cálcio foi maior no grupo NAM (p < 0,001). Conclui-se que o leite materno foi consumido por metade dos lactentes e, constatou-se alto consumo de outros leites por crianças amamentadas. As crianças de mães com menor escolaridade consumiram em maior frequência o leite de vaca, entretanto a quantidade ingerida foi menor. Aqueles em aleitamento materno complementado apresentaram maior consumo energético e maior ganho de peso mensal.
113

Funcionais paramÃtricos elÃpticos em variedades riemannianas / Elliptic parametric functional in manifolds riemannian

Marcelo Ferreira de Melo 07 August 2009 (has links)
CoordenaÃÃo de AperfeiÃoamento de NÃvel Superior / Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Neste trabalho, consideramos funcionais paramÃtricos elÃpticos como generalizaÃÃes naturais para o clÃssico funcional Ãrea. Calculamos a primeira variaÃÃo de tais funcionais e, a partir da equaÃÃo de Euler-Lagrange, definimos a curvatura mÃdia anisotrÃpica de uma hipersuperfÃcie imersa em uma variedade Riemanniana como generalizaÃÃo natural da curvatura mÃdia usual. Em seguida, estabelecemos a fÃrmula da segunda variaÃÃo e classificamos as hipersuperfÃcies rotacionalmente simÃtricas que possuem curvatura mÃdia anisotrÃpica constante. A fim de compreender a estabilidade dos exemplo rotacionais,deduzimos a primeira e a segunda fÃrmulas de Minkowski. AlÃm disso, no contexto anisotrÃpico, apresentamos as equaÃÃes fundamentais de Weingarten, Codazzi e Gauss e, por fim, estudamos a harmonicidade da aplicaÃÃo de Gauss. / It is stated that critical points of a parametric elliptic functional in a Riemannian manifold are hypersurfaces with prescrebed anisotropic mean curvature. We prove that the anisotropic Gauss map of surfaces immersed in Euclidean space with constant anisotropic mean curvature is a harmonic map. In the case of rotatioally invariat functionals in some homogeneous three-dimensional ambients, we present a abridged version of a existence result for constant anisotropic mean curvature surfaces as cylinders, spheres, tori and annuli corresponding to the anisotropic analogs of onduloids and nodoids. In the Euclidean case M = R3, examples of stable critical points are provided by the Wulff shapes associated to functional F. Paralleling the case of constant curvature mean spheres, a characterization of Wulff shapes is provided, which answers affirmatively a question posed by M. Koiso and B. Parmer in [13].
114

Métodos para resolução de EDOs stiff resultantes de modelos químicos atmosféricos / Methods for solving stiff ODEs resulting from atmospheric chemistry models

Larissa Marques Sartori 21 February 2014 (has links)
Problemas provenientes de química atmosférica, possuem uma característica especial denominada stiffness, indicando que as soluções dos sistemas de equações diferenciais ordinárias envolvidos variam em diferentes ordens de grandeza. Isso faz com que métodos numéricos adequados devam ser aplicados no intuito de obter soluções numéricas convergentes e estáveis. Os métodos mais eficazes para tratar este tipo de problema são os métodos implícitos, pois possuem uma região de estabilidade ilimitada que permite grandes variações no tamanho do passo, mantendo o erro de discretização dentro de uma dada tolerância. Mais precisamente, estes métodos possuem a propriedade de A-estabilidade ou A(alpha)-estabilidade. Neste trabalho, comparamos dois métodos numéricos com estas características: o método de Rosenbrock e a fórmula de diferenciação regressiva (métodos BDF). O primeiro é usado no módulo de Química do modelo CCATT-BRAMS do Centro de Previsão de Tempo e Estudos Climáticos (CPTEC), sendo incluído na previsão numérica de regiões com intensas fontes de poluição. Este é um método de passo simples implícito com um controle de passo adaptativo. Aqui empregamos também o segundo, um método de passo múltiplo que dispõe de uma fórmula que permite variação no tamanho do passo e na ordem, empregando o pacote LSODE. Os resultados de nossas comparações indicam que os métodos BDF podem se constituir em interessante alternativa para uso no CCATT-BRAMS. / Problems from atmospheric chemistry have a special characteristic denominated stiffness, indicating that the solutions of the involved ordinary differential equations systems vary in different scales. This means that appropriate methods should be applied in order to get convergent and stable numerical solutions. The most powerful methods to treat problems like this are implicit schemes, since they have unlimited stabity regions, allowing large variations in step size, keeping the discretization error within a given tolerance. More precisely, these methods have the A-stability or A(alpha)-stability properties. In this work, we compared two numerical methods with those characteristics: the Rosenbrock method and the backward differentiation formula (BDF). The first one is employed in the Chemistry package within CCATT-BRAMS local weather model of CPTEC (Center for Weather Forecasts and Climate Studies), which is mainly used for the numerical forecasting of regions with intense pollution. This is a implicit one-step method with an adaptative stepsize control. We compare it with the second method, a multistep method with a formula that allows variations in step size and order, with the help of the LSODE package. The results of our comparisons indicate that BDF methods are an interesting alternative to be used within CCATT-BRAMS.
115

Soluções analíticas e numéricas de equações polinomiais / Analytical and numerical solutions of polynomial equations

Livia Novaes Teixeira Passos 07 December 2017 (has links)
As equações polinomiais são estudadas desde a antiguidade e atualmente são utilizadas, por exemplo, para modelar problemas do cotidiano nas mais variadas áreas do conhecimento. As técnicas de solução de equações polinomiais nem sempre são triviais, principalmente quando envolvem equações de alta ordem e raízes complexas. O ensino desse tema no Ensino Básico é limitado a equações de segundo ou terceiro grau e coeficientes inteiros, o que restringe a aplicação em problemas mais realistas. Assim, o objetivo deste trabalho é trazer uma contribuição aos estudantes, aos professores do Ensino Básico e aos demais interessados, apresentando um material que aborde técnicas de resolução para equação polinomial de diversas naturezas. Iniciamos por uma revisão dos números complexos e dos polinômios, suas operações e propriedades. Embasamos o trabalho com teoremas e permeamos de exemplos com um crescente grau de dificuldade. Dividimos as técnicas de resolução em analíticas e numéricas. Entre as primeiras, tratamos das relações de Girard, das fórmulas resolventes e de alguns casos particulares de equações. Entre as técnicas numéricas, estudamos o método de Newton, o método das secantes e o método de Newton-Bairstow, este último para encontrar raízes complexas. / Polynomial equations have been studied since antiquity and are currently used, for example, to model everyday problems in the most varied areas of knowledge. The solution techniques of polynomial equations are not always trivial, especially when they involve high order equations and complex roots. The teaching of this subject in Basic Education is limited to second or third degree equations and integer coefficients, which restricts the application to more realistic problems. Thus, the objective of this work is to bring a contribution to students, teachers of Basic Education and other interested parties, presenting a material that treats of resolution techniques for polynomial equation of different natures. We begin with a review of complex numbers and polynomials, their operations and properties. We support the work with theorems and permeate examples with an increasing degree of difficulty. We divide the techniques of resolution into analytical and numerical. Among the first, we deal with Girards relations, the resolvent formulas, and some particular cases of equations. Among numerical techniques, we studied the Newton method, the secant method, and the Newton-Bairstow method, the last one to find complex roots.
116

Representações de hiperálgebras de laços e álgebras de multi-correntes / Representations of hyper loop algebras and multi curret algebras

Biânchi, Angelo Calil, 1984- 20 August 2018 (has links)
Orientadores: Adriano Adrega de Moura, Vyjayanthi Chari / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Matemática, Estatística e Computação Científica / Made available in DSpace on 2018-08-20T03:20:21Z (GMT). No. of bitstreams: 1 Bianchi_AngeloCalil_D.pdf: 2798335 bytes, checksum: bc4f008ee1c7b89870e5bf16c8ab0a67 (MD5) Previous issue date: 2012 / Resumo: Este trabalho é dedicado ao estudo de alguns assuntos da teoria de representações de certas álgebras que podem ser vistas como generalizações do conceito de álgebras de Kac-Moody am. De modo geral, o trabalho é dividido em duas partes: na primeira delas, abordamos questões sobre as representações de dimensão finita das hiperálgebras de laços torcidas e, na outra, abordamos certas propriedades homológicas da categoria de representações de uma álgebra de Lie multi-graduada, as quais são extremamente úteis para obter uma generalização do conceito de módulos de Kirillov-Reshetikhin / Abstract: This work is dedicated to the study of some aspects of the representation theory of certain algebras which can be regarded as generalizations of the concept of affine Kac- Moody algebras. The work is divided into two parts: the first is concerned with the finite-dimensional representations of twisted hyper loop algebras and the other focuses on certain homological properties of the category of representations of a multigraded Lie algebra which are useful to study a generalization of the concept of Kirillov-Reshetikhin modules / Doutorado / Matematica / Doutor em Matemática
117

Intégration numérique et calculs de fonctions L

Molin, Pascal 18 October 2010 (has links)
Cette thèse montre la possibilité d’une application rigoureuse de la méthode d’intégrationnumérique double-exponentielle introduite par Takahasi et Morien 1974, et sa pertinence pour lescalculs à grande précision en théorie des nombres. Elle contient en particulier une étude détailléede cette méthode, des critères simples sur son champ d’application, et des estimations rigoureusesdes termes d’erreur.Des paramètres explicités et précis permettent de l’employer aisément pour le calcul garantide fonctions définies par des intégrales.Cette méthode est également appliquée en détail au calcul de transformées de Mellin inversesde facteurs gamma intervenant dans les calculs numériques de fonctions L. Par une étude unifiée,ce travail démontre la complexité d’un algorithme de M. Rubinstein et permet de proposer desalgorithmes de calcul de valeurs de fonctions L quelconques dont le résultat est garanti et dont lacomplexité est meilleure en la précision. / This thesis contains a detailed study of the so-called double exponential integration formulasintroduced by Takahasi and Moriin 1974,and provides explicit bounds forarigorous applicationof the method in number theory.Accurate parameters are given, which makes it possible to use it as a blackbox for the rigorouscomputation of functions defined by integrals.It also deals with numerical computations of L functions. The complexity of analgorithm dueto M. Rubinstein is proven. In the context of double-exponential transformation, a new algorithmis provided whose complexity is low in terms of precision.
118

Finanční analýza Pivovaru Bernard / Financial analysis of the Rodinný pivovar BERNARD, a.s. brewery

Janoušek, Adam January 2014 (has links)
The goal of this thesis is to evaluate the financial position of the chosen company using the standard methods and techniques. The thesis is divided into two parts - in the first the detailed description of the methods and tests used is presented. The second part of the thesis focuses in the actual analysis which includes the horizontal and vertical analysis of the balance sheet and the income statement, asset management ratios including the DuPont model, the analysis of the working capital and the analysis using the formulas for predicting the bankruptcy and assesing the value.
119

Modelování a chování složených soustav ve střídavém elektrickém poli / Modelling and behaviour of composite systems in AC electric field

Matoušek, Jiří January 2010 (has links)
This work deals with modeling of progression of dielectric variables and mixture formulas for solution of properties of composite materials in dependency on frequency. Theoretical part of the work explains physical principles of polarisation mechanisms and influence on dielectric constant with changing temperature and frequency. In theoretical part processes inside the composite material, which is in electrical field are described. The work contains summary of mixture formulas and methods of their derivation. Program for use in education is a part of the work. It allows modelling of progression of dielectric variables in dependency on frequency and Cole-Cole circle diagram. In mixtures it allows modelling of frequency dependencies of dielectric constant in accordance to Maxwell's, Bőttcher's and Lichtenecker's mixture formulas.
120

Recipes in Many Hands: Local Networks and Empirical Knowledge in the Recetarios of Early Modern Spain

Basile, Nicole Parisina January 2024 (has links)
This dissertation addresses the role of recipe writing in the culture and development of empiricism in Spain over the course of the long sixteenth century. In 1516, Charles of Habsburg was named King of Spain, and began his project to consolidate and extend Spanish rule, picking up where his grandparents, Isabel and Ferdinand, left off. While the Iberian Monarchy attempted to control empirical practice and knowledge of the natural world by way of its administrative institutions, Europe was developing a bit of a recipe habit. Across sixteenth and seventeenth century Europe, there was an surge in readership of recipe books, manuals, books of secrets, and artes, as well as any other book containing recipes (including natural histories). Much like today, there was a rich culture of recipe writing and exchange. When it came to household affairs such as cooking, toiletries and cosmetics, cleaning, and pharmaceuticals, most people had their own practices, and many were also willing to share their tested recipes with others. As I argue in this dissertation, local experimentation and the exchange of said knowledge took place among heterogenous networks of practitioners across Habsburg Spain. While the Crown was influenced by these practices and often appropriated them as well, it was not the only force behind the empirical turn in the history of science and medicine in Spain. Rather, local practitioners and cohorts of experimenting nobles and laypeople alike all played a role in the turn toward experimentation as scientific method.

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