• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1920
  • 1832
  • 1567
  • 324
  • 163
  • 135
  • 114
  • 98
  • 61
  • 57
  • 54
  • 36
  • 31
  • 30
  • 30
  • Tagged with
  • 6947
  • 1681
  • 1386
  • 989
  • 979
  • 974
  • 345
  • 322
  • 313
  • 304
  • 301
  • 300
  • 291
  • 283
  • 270
  • 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.
1101

Obtenção de revestimentos comestíveis a base de pectina como veículo para micro- organismos probióticos e aplicação em cenoura e goiaba minimamente processadas / Obtaining of edible coatings on the basis of pectin as a vehicle for microorganisms probiotics and application in carrots and guavas minimally processed

Rodrigues, Marcela Zonta 06 September 2017 (has links)
Submitted by Marco Antônio de Ramos Chagas (mchagas@ufv.br) on 2017-12-21T11:38:46Z No. of bitstreams: 1 texto completo.pdf: 4243684 bytes, checksum: f5b9f5d1f1542cc767288674a7a4710f (MD5) / Made available in DSpace on 2017-12-21T11:38:46Z (GMT). No. of bitstreams: 1 texto completo.pdf: 4243684 bytes, checksum: f5b9f5d1f1542cc767288674a7a4710f (MD5) Previous issue date: 2017-09-06 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / As culturas probióticas estão disponíveis para o consumidor, principalmente, em produtos lácteos. Contudo o interesse pela incorporação destes micro-organismos em outras bases alimentares é crescente. As matrizes vegetais são boa alternativa para a incorporação destes micro-organismos, no entanto é necessário o desenvolvimento de diferentes técnicas para inserir as bactérias probióticas em vegetais. Esta pesquisa objetivou desenvolver revestimento comestível a base de pectina de baixa metoxilação para veicular micro-organismos probióticos em cenoura e goiaba minimamente processadas. Na primeira etapa do estudo, foi produzido o revestimento a base de pectina de baixa metoxilação, sendo os tratamentos controle e adicionados de bactérias probióticas (Lactobacillus acidophilus LA3, Lactobacillus plantarum (CH6072 e L286), Lactobacillus paracasei BGP1, Lactobacillus acidophilus LA3 em combinação com Lactobacillus plantarum (CH6072 e L286), Lactobacillus acidophilus LA3 em combinação com Lactobacillus paracasei BGP1 e Lactobacillus plantarum (CH6072 e L286) em combinação com Lactobacillus paracasei BGP1). Os revestimentos comestíveis foram avaliados quanto à sua estabilidade microbiológica (viabilidade e resistência às condições gastrointestinais simuladas in vitro das culturas probióticas e atividade antimicrobiana frente à Listeria innocua ATCC33090 e Escherichia coli ATCC11229), física (viscosidade, cor, índice de brancura e turbidez) e química (pH) durante 12 dias de armazenamento. Na segunda etapa do estudo, avaliou-se a aplicação do revestimento comestível em cenoura e goiaba minimamente processadas e a estabilidade dos produtos obtidos armazenados a 4 °C. Cenoura e goiaba minimamente processadas contendo os revestimentos comestíveis foram avaliadas quanto a qualidade microbiológica, viabilidade e resistência às condições gastrointestinais in vitro dos probióticos, microscopia eletrônica de varredura (MEV), perda de massa, firmeza, composição da cor, pH, acidez total titulável e teor de sólidos solúveis totais. O revestimento comestível apresentou-se como bom carreador de bactérias probióticas, além de alguns tratamentos apresentarem atividade antimicrobiana. A adição de bactérias probióticas ao revestimento comestível alterou (p<0,05) pH, cor, índice de brancura e turbidez. As bactérias probióticas apresentaram-se viáveis quando os revestimentos comestíveis foram adicionados as cenoura e goiaba minimamente processadas. A MEV mostrou que as bactérias probióticas apresentaram-se bem distribuídas por toda a superfície da cenoura e goiaba minimamente processadas revestidas. A adição do revestimento cometível às fatias de cenoura e goiaba minimamente processadas não alterou (p>0,05) a qualidade microbiológica e as características físicas e químicas dos produtos avaliados. Portanto, o revestimento comestível a base de pectina de baixa metoxilação contendo bactérias probióticas é uma boa alternativa para veicular estes micro-organismos, através dos vegetais minimamente processados, até o consumidor. / The probiotic cultures are available for the consumer especially in dairy products. However, the interest by the incorporation of these microorganisms in other food bases is growing. The vegetables matrices are a good alternative for the incorporation of these micro-organisms, it is necessary to the development of different techniques to deliver the probiotic bacteria to vegetables. The objective of this research was to develop low methoxylated pectin based edible coating to deliver probiotic microorganisms to minimally processed carrots and guavas. In the first stage of the study, low methoxylation pectin edible coating was produced, control treatment and addition of probiotic bacteria (Lactobacillus acidophilus LA3, Lactobacillus plantarum (CH6072 e L286), Lactobacillus paracasei BGP1, Lactobacillus acidophilus LA3 in combination with Lactobacillus plantarum (CH6072 e L286), Lactobacillus acidophilus LA3 in combination with Lactobacillus paracasei BGP1 e Lactobacillus plantarum (CH6072 e L286) in combination with Lactobacillus paracasei BGP1). The edible coatings were evaluated for their microbiological stability (viability and resistance to simulated in vitro gastrointestinal conditions of probiotic cultures and antimicrobial activity against Listeria innocua ATCC33090 and Escherichia coli ATCC11229), physical (viscosity, color, whiteness index and turbidity) and chemical (pH) for 12 days storage. In the second stage of the study, were evaluated the application of the edible coating in minimally processed carrots and guavas and the stability of the obtained products stored at 4 ° C. Minimally processed carrots and guavas containing the edible coatings were evaluated for microbiological quality, viability and resistance in vitro gastrointestinal conditions of probiotics, scanning electron microscopy (SEM), loss of mass, firmness, color composition, pH, titratable total acidity and total soluble solids content. The edible coating presented as a good carrier of probiotic bacteria, in addition to some treatments presenting antimicrobial activity. The addition of probiotic bacteria to the edible coating altered (p<0.05) pH, color, whiteness index and tubidity. Probiotic bacteria were viable when edible coatings were added to minimally processed carrots and guavas. SEM showed that probiotic bacteria were well distributed throughout the surface of minimally processed coated carrot and guava. The addition of the edible coating minimally processed carrot and guava did not modify (p> 0.05) the microbiological quality and the physical and chemical characteristics of the evaluated products. Therefore, the low methoxylation pectin edible coating containing probiotic bacteria is a good alternative for transference these microorganisms through minimally processed vegetables to the consumer.
1102

Facilitação pode incrementar a capacidade de adaptação de actinobactérias e rizóbios "in vitro" / Facilitation can increase actinobacteria adaptation capacity and rhizobia "in vitro"

Silva, Valéria Maria Araújo January 2016 (has links)
SILVA, Valéria Maria Araújo. Facilitação pode incrementar a capacidade de adaptação de actinobactérias e rizóbios "in vitro". 2016. 89 f. Dissertação (Mestrado em ecologia e recursos naturais)- Universidade Federal do Ceará, Fortaleza-CE, 2016. / Submitted by Elineudson Ribeiro (elineudsonr@gmail.com) on 2016-07-28T16:41:56Z No. of bitstreams: 1 2016_tese_vmasilva.pdf: 1606701 bytes, checksum: fe47fb5ee02d36bddccb38ea078f8a37 (MD5) / Approved for entry into archive by José Jairo Viana de Sousa (jairo@ufc.br) on 2016-08-02T14:41:59Z (GMT) No. of bitstreams: 1 2016_tese_vmasilva.pdf: 1606701 bytes, checksum: fe47fb5ee02d36bddccb38ea078f8a37 (MD5) / Made available in DSpace on 2016-08-02T14:41:59Z (GMT). No. of bitstreams: 1 2016_tese_vmasilva.pdf: 1606701 bytes, checksum: fe47fb5ee02d36bddccb38ea078f8a37 (MD5) Previous issue date: 2016 / The natural environment is marked by an intricate network of biotic interactions that shape the structure of ecological communities. The presence of positive ecological interactions between microbial populations in soils semiarid regions, has great importance in structuring the local soil microbiota. In this work, actinomycetes strains of rhizobia and coming from rhizosphere of Park National Ubajara-CE, were evaluated for the ability to grow through cooperative metabolic mechanisms. Of the 27 evaluated actinomycetes, 22 showed compatibility with rhizobia. The strains UB-05, UB-07, UB-08, UB-11 and UB-21 stood out in facilitating tests for amylase and cellulase. The metabolic activity of actinomycetes helped the development of rhizobia strains. / O ambiente natural é marcado por uma intrincada rede de interações bióticas que moldam a estrutura das comunidades ecológicas. A presença de interações ecológicas positivas entre populações microbianas em solos de regiões semiáridas, possui grande relevância na estruturação da microbiota do solo local. Neste trabalho, cepas de actinobactérias e rizóbios oriundas de solo rizosférico do Parque Nacional de Ubajara-CE, foram avaliadas quanto à capacidade de crescerem através de mecanismos metabólicos cooperativos. Das 27 actinobactérias avaliadas, 22 apresentaram compatibilidade com rizóbios. As cepas UB-05, UB-07, UB-08, UB-11 e UB-21, destacaram-se nos ensaios de facilitação para amilase e celulase. A atividade metabólica de actinobactérias auxiliou o desenvolvimento das cepas de rizóbios.
1103

Modelo conceitual de controle orçamentário à luz do GECON em empresas de pequeno porte: estudo de caso

Linhares, Eduardo Rodrigues January 2005 (has links)
LINHARES, Eduardo Rodrigues. Modelo conceitual de controle orçamentário à luz do GECON em empresas de pequeno porte: estudo de caso. 2005. 182 f. ; Dissertação (mestrado) - Universidade Federal do Ceará, Faculdade de Economia, Administração, Atuária, Contabilidade e Secretariado, Fortaleza-CE, 2005. / Submitted by Dioneide Barros (dioneidebarros@gmail.com) on 2016-09-23T16:07:03Z No. of bitstreams: 1 2005_dis_ erlinhares.pdf: 1279060 bytes, checksum: 9ea1243ecb4565838eb44dd1fbdf4c2f (MD5) / Approved for entry into archive by Dioneide Barros (dioneidebarros@gmail.com) on 2016-09-27T14:16:35Z (GMT) No. of bitstreams: 1 2005_dis_ erlinhares.pdf: 1279060 bytes, checksum: 9ea1243ecb4565838eb44dd1fbdf4c2f (MD5) / Made available in DSpace on 2016-09-27T14:16:35Z (GMT). No. of bitstreams: 1 2005_dis_ erlinhares.pdf: 1279060 bytes, checksum: 9ea1243ecb4565838eb44dd1fbdf4c2f (MD5) Previous issue date: 2005 / This work has an aim to verify the applicability of a budget plan, proposed by GECON, acting as an instrument that helps the manager to get the expected results for his products, electing the economic result as a valuator of taken decisions, aiming the correction of directions which take to the accomplishment of an expected goal, in terms of results. The Method used in this research was a deduction one, setting up as a methodologic objective a describing investigation, using the proceedings in a Study of Case. It was chosen a small company to inform about the universe of the problem-situation. For this, it was developed a qualitative approach. In relation to GECON’s model, it is said, by this work, that it is a very good tool, provided that it’s able to identify the inflation variations and very useful in plans adjustment, volumes, efficiency and prices, giving to the manager a detailed report, in monetary terms, concern on possible deviations, helping a pro-active behavior from the manager’s part. This study analyses standards, as an physical terms as in a monetary aspect, their alternations and how they influence in the process of reaching goals in the business world. This work proposes a price-index, an internal one, specifical for the company, considering the reality in which it is inserted. The present works reputes GECON’s model as the best one to satisfy the manager’s information needs, according to conclusions taken during the stages of the research adjoining the studied company. Key / Este trabalho tem como objetivo verificar a aplicabilidade do modelo de processo orçamentário proposto pelo GECON, atuando como instrumento que auxiliará o gestor a atingir os resultados desejados para seus produtos, elegendo o resultado econômico como validador das decisões tomadas, com vistas à correção dos rumos que levam à consecução da meta de resultado esperada. O Método utilizado para esta pesquisa foi o dedutivo, tendo como objetivo metodológico a pesquisa descritiva, utilizando os procedimentos do Estudo de Caso, no qual, através da verificação dos procedimentos do processo orçamentário em Uma empresa de pequeno porte respondeu à situação problema. Para isso, utilizou-se a abordagem qualitativa. O modelo proposto pelo GECON tem a virtude de apoiar todo o processo de gestão, identificando as variações de inflação, ajuste de planos, volumes, eficiência e preços, dos quais o gestor obtém um relato detalhado, de onde e em quanto, em termos monetários, foram os desvios, subsidiando, para que possa agir pró-ativamente, a busca da consecução dos resultados esperados. A identificação de padrões, tanto em termos físicos quanto em termos monetários, como também suas alterações, para tornar a meta viável, é importante ponto desta Dissertação. O trabalho propõe a utilização de um índice interno de preços, específico para a empresa, como forma complementar ao processo de planejamento operacional, auxiliando, principalmente, na fase do plano original e corrigido, podendo ser utilizado para outros fins. Conclui-se que o modelo apresentado neste trabalho satisfaz à necessidade informativa do gestor, no alcance de um melhor resultado, levando-se em conta a realidade vivenciada pela empresa inquirida.
1104

Crescimento de recepas de cafeeiro eanálise funcional dos micro- organismos do solo em sistema agroflorestal com macaúba / Coffee recepa of growth and functional analysis of soil microorganisms in agroforestry system with macaúba

Medina, Juliana Martins 19 February 2016 (has links)
Submitted by Reginaldo Soares de Freitas (reginaldo.freitas@ufv.br) on 2016-07-27T11:31:42Z No. of bitstreams: 1 texto completo.pdf: 991628 bytes, checksum: be2f658b43f3b706acbad16e7537bd31 (MD5) / Made available in DSpace on 2016-07-27T11:31:42Z (GMT). No. of bitstreams: 1 texto completo.pdf: 991628 bytes, checksum: be2f658b43f3b706acbad16e7537bd31 (MD5) Previous issue date: 2016-02-19 / Fundação de Amparo à Pesquisa do Estado de Minas Gerais / A Agroecologia é uma forma de orientar as diferentes estratégias de desenvolvimento rural sustentável, avaliando as potencialidades dos sistemas agrícolas, através de perspectivas social, econômica e ecológica.Sistemas agrícolas que promovam a manutenção ou o aumento das populações microbianas benéficas do solo trazem muitas vantagens tanto para o ambiente quanto para a produção agrícola. Logo é importante buscar práticas agrícolas que visem à conservação dos microrganismos no solo.Diversas práticas e processos contribuem para o aumento e preservação da diversidade microbiana benéfica do solo, tais como a rotação de cultura, plantio direto, o consórcio, adubação verde, adubação orgânica, uso de cobertura morta e os sistemas agroflorestais (SAF).A avaliação das características microbiológicas do solo nos SAF é importante para a compreensão mais aprofundada de sua interferência positiva no solo, refletindo aspectos bioquímicos relacionados com a ciclagem e disponibilização de e com a dinâmica da matéria orgânica. Dessa forma este trabalho que teve foco de estudo o SAF composto por cafeeiros e macaubeiras, onde os objetivos principais foram: avaliar o crescimento vegetativo de cafeeiro sem consórcio com a macaúba em diferentes distâncias das árvores e avaliar as características químicas, a diversidade das comunidades microbianas do solo em cafeeiros consorciados com macaubeiras. / Agroecology is a way of guiding the different strategies of sustainable rural development, assessing the potential of agricultural systems, through social, economic and ecological perspectives. agricultural systems that promote the maintenance or increase in beneficial microbial populations Soil bring many benefits to both the environment and to agricultural production. Logo is important to seek agricultural practices aimed at conservation of soil microorganisms. Several practices and processes contribute to the increase and preservation of beneficial microbial diversity of the soil, such as crop rotation, tillage, the consortium, green manure, organic manure, mulch use and agroforestry systems (SAF). The evaluation of microbiological characteristics of the soil in the SAF is important for better understanding of their positive interference in the soil, reflecting biochemical aspects of cycling and availability of and the dynamics of organic matter. Thus this work was study focused on the SAF consists of coffee and macaubeiras, where the main objectives were to evaluate the vegetative growth of coffee plants in consortium with macaúba at different distances from the trees and evaluate the chemical characteristics, the diversity of microbial communities soil in coffee trees mixed with macaubeiras.
1105

Petroleum effects on soil microbial communities / Efeito do petróleo sobre comunidades microbianas do solo

Morais, Daniel Kumazawa 29 July 2015 (has links)
Submitted by Reginaldo Soares de Freitas (reginaldo.freitas@ufv.br) on 2016-09-05T12:12:19Z No. of bitstreams: 1 texto completo.pdf: 1636988 bytes, checksum: 82f0e2495b29689e04e4a8d2ad963aa3 (MD5) / Made available in DSpace on 2016-09-05T12:12:19Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1636988 bytes, checksum: 82f0e2495b29689e04e4a8d2ad963aa3 (MD5) Previous issue date: 2015-07-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O petróleo é a principal fonte de energia no Brasil, onde o consumo de óleo continua subindo desde 2013, atingindo atualmente 2.2% do total de energia consumida no mundo. A descoberta recente de petróleo nas baias do Espirito Santo, Campos e Santos, pode representar uma excelente oportunidade para atender as demandas energéticas nacionais. Entretanto, a exploração de petróleo oferece riscos a microbiota e toda a vida marinha. Microrganismos são responsáveis pela ciclagem de nutrientes, podem degradar compostos orgânicos recalcitrantes e muitas espécies são reportadas como sensíveis à contaminação por hidrocarbonetos do petróleo. Esse trabalho teve o objetivo de avaliar as alterações na comunidade microbiana em solos sob a contaminação por petróleo e avaliar os efeitos do Co-produto de biodiesel (BCP) como um agente protetor da microbiota do solo perante a adição de petróleo. Foram utilizados solos da Ilha da Trindade, e da estação de pesquisa Highfield no Rothamsted Research, UK. Foram montados microcosmos com 20 gramas de solo e os tratamentos utilizaram petróleo intemperizado. Os solos foram incubados a 26° C com correção da umidade para cerca de 60% da capacidade de retenção de água dos solos. Foi utilizada a medição de evolução de CO2 para avaliar a atividade do solo, durante o período de incubação, e a extração de DNA genômico do solo, ao final do período de incubação, para avaliar as mudanças nas comunidades microbianas dos tratamentos e controles. O DNA foi submetido para o sequenciamento de amplicons de 16S rDNA para a avaliação de Bacteria e Archaea e de amplicons da região ITS1 para a avaliação de Fungos utilizando a plataforma Illumina HiSeq. Foi feita a comparação das diversidades alpha e beta e análise das alterações taxonômicas. Essa tese está dividida em dois capítulos. O primeiro descreve os efeitos do petróleo nas comunidades microbianas do solo da Ilha da Trindade. No segundo capítulo foi testado o efeito protetor do BCP sobre a microbiota dos solos da Ilha da Trindade, do campo Bare Fallow e do campo Grassland do Rothamsted Research contra a adição de óleo. O petróleo teve um grande efeito negativo sobre a diversidade microbiana da Ilha da Trindade, mas não mudou a diversidade microbiana dos solos agrícolas do Rothamsted. A comparação taxonômica mostrou aumento do filo Actinobacteria, mudanças em várias classes de Proteobacteria e redução da classe Nitrosphaerales do filo Archaea. Esse é o primeiro esforço para aquisição de conhecimento sobre o efeito da contaminação de solos de uma ilha oceânica brasileira com petróleo. Essa informação é importante para guiar qualquer futura estratégia de biorremediação que se faça necessária. / Crude oil is still the dominant energy source in Brazil where oil consumption keeps rising since 2013, reaching nowadays 2.2% of the world‟s energy consumption. A recent discovery of crude oil reservoirs at the Espirito Santo, Campos and Santos basins, can represent an excellent opportunity to meet the country‟s economic and energetic demands. However, offshore exploration offers risks to the microbiota and the whole sea life. Microbes are responsible for nutrient cycling can degrade recalcitrant organic compounds and several species have been reported as sensitive to petroleum hydrocarbons. This work aimed to evaluate microbial community shifts in soils under crude oil contamination and assess the effects of Biodiesel co-product (BCP) as a protecting agent of soil microbiota under crude oil addition. We used soils from the Trindade Island and from the Highfield research station at Rothamsted Research, UK. We assembled microcosms of 20 grams and contaminated the soils using weathered crude oil. Soils were incubated at 26° C with moisture correction to ca. 60% water holding capacity. We used CO2 evolution measurements to evaluate soil activity, during the incubation, and soil genomic DNA extraction, at the end of incubation period, to evaluate microbial community changes from treatments and controls. DNA was submitted to amplicon sequencing of 16S rDNA for Bacteria and Archaea and the ITS1 region for Fungi using Illumina MiSeq platform. We compared alpha and beta-diversity and taxonomic shifts. This thesis is divided in two chapters. The first describes the effects of crude oil on Trindade Island‟s soil microbial communities. In the second chapter we tested the protective effects of BCP on Trindade Island, Rothamsted‟s Bare Fallow and Grassland soils, against the amendment with crude oil. Crude oil had a major negative effect on microbial diversity for Trindade Island, but didn‟t change the diversity of Rothamsted agricultural soils. Taxonomy comparisons showed rise of the Actinobacteria phylum, shifts in several Proteobacteria classes and reduction of the Archaea class Nitrososphaerales. This is the first effort in acquiring knowledge concerning the effect of crude oil contamination in soils of a Brazilian oceanic island. This information is important to guide any future bioremediation strategy that can be required.
1106

Causalité en sciences sociales : quelques applications en microéconométrie appliquées à l'économie de la santé et du travail / Causality in social science : application in micro-econometrics applied to health and work economics

Moussa, Kouamé Richard 09 December 2016 (has links)
L'objectif général de cette thèse est d'une part de rendre compte du traitement économétrique des phénomènes de causalité en sciences sociales et d'autre part de proposer des applications à l'étude de la causalité entre la santé et l’emploi du travail, à l’étude des décisions de retraite anticipée en relation avec la santé, la richesse et les préférences pour le futur.Pour l’analyse de la causalité santé-emploi, deux approches sont utilisées dans le cadre d’une analyse ex-post. L’approche paramétrique qui consiste en l’estimation d’un probit bivarié en panel qui inclut les valeurs retardées des variables expliquées parmi les explicatives afin de mesurer la causalité au sens de Granger entre les deux phénomènes. Le problème d’endogénéité est ainsi résolu. Les conditions initiales sont prises en compte via des équations spécifiques. Les effets individuels rendent compte de l’hétorogénéité individuelle dans l’analyse de la causalité. La seconde approche est non paramétrique et basée sur la mesure de causalité de Kullback. Elle permet de mesurer la dynamique des relations de causalité ainsi que ses déterminants.Quant à l’analyse de la décision de retraite anticipée, elle est faite grâce à un modèle structurel dynamique. Ce modèle intègre des fonctions de production et de consommation de stock de santé ainsi qu’une fonction d’utilité inter temporelle. Les conditions d’équilibre de ce modèle permettent de prédire les probabilités de retraite anticipée. / The main objective of this thesis is to investigate on the econometric treatment of causality in social sciences and to provide some applications on the establishment of causality between health condition and job status, and on the early retirement decision based on health, estate and preferences for future.To analyze the causality between health and job statuses, two approaches are used in the ex-post framework. The parametric approach involves estimating a bivariate probit panel model that includes lagged values of the dependent variables as explanatory to measure Granger causality. Thus, the problem of endogeneity is accounted for. The initial conditions are accounted for by introducing specific equations. Individual effects allow dealing with individual heterogeneity. The second approach is a nonparametric one and is based on the Kullback causality measures. This approach allows measuring the dynamic of the causal links and its determinants.For analyzing the early retirement decision, we use a dynamic structural model. This model deals with health stock production and consumption functions, and with an inter temporal utility function. The first order conditions of the model allow predicting the probabilities of early retirement.
1107

Investigation de la dispersion des ondes élastiques dans les milieux micro-structurés : applications aux poutres phononiques / Investigation of elastic wave dispersion in micro-structured media with a focus on phononic strip applications

Coffy, Etienne 13 December 2017 (has links)
La micro-structuration périodique d’un milieu influence fortement la propagation des ondes élastiques. Ces structures, nommées cristaux phononiques, permettent de manipuler les ondes en les ralentissant, voire en interdisant leurs propagations pour certaines gammes de fréquences appelées bandes interdites. Au cours de la thèse, la dispersion des ondes élastiques dans des structures composées de piliers résonants périodiquement attachés à des poutre structurées a été numériquement et expérimentalement étudiée. Basées sur la combinaison de résonances locales avec des réflexions multiples de Bragg, des poutres phononiques avec de larges bandes interdites ont été obtenues. En particulier, une poutre phononique avec une bande interdite présentant une largeur relative de 94% autour du mégahertz a été fabriquée et caractérisée.Les poutres phononiques ont été utilisées pour améliorer les facteurs de qualité des résonances de défauts insérés en fin, ou entre les poutres. Une amélioration d’un facteur 8 d’une résonance d’un défaut encastrée-libre accroché à une poutre phononique a été démontrée. Cette amélioration est attribuée au confinement de l’énergie mécanique par la poutre phononique dont la bande interdite recouvre la fréquence de résonance du défaut. En parallèle de ces activités, une plateforme pompe sonde hétérodyne femtoseconde a été utilisée pour caractériser la propagation des ondes élastiques à la surface de films minces microstructurés. Une forte anisotropie ainsi qu’une réduction des vitesses des ondes a été mis en évidence. Ces observations ont été reliées aux micro-structurations particulières des films, avec des simulations en éléments finis. / Periodic microstructures in media strongly influences the propagation of elastic waves. These structures, known as phononic crystals, allow the manipulation of waves such as their slowdown, or their prohibition for frequency ranges called band gaps.During the thesis, the dispersion of elastic waves propagating through structures composed of resonant pillars periodically attached to tailored strips was studied. Based on the combination of Bragg scattering and local resonances, phononic strips with large band gaps were achieved. Notably, a phononic strip with a band gap displaying a relative width of 94% in the megahertz range was demonstrated.Phononic strips were then used to ameliorate the resonances’ quality factors for defects inserted at the end, or within the strips. An improvement by a factor of 8 of the resonance quality factor of a beam clamped to a phononic strip was achieved. This improvement was assigned to the mechanical energy confinement linked with the phononic strip, as its band gap overlaps the resonance frequency of the defect.In parrallel to these studies, a femtosecond heterodyne pump probe setup was used to characterize the waves propagation on the surface of microstructured thin films. A strong anisotropy as well as a speed reduction were observed. These observations were linked to the particular microstructures of the films, using numerical simulations performed with the Finite Element Method.
1108

Geração de trabalho e renda de forma sustentável através da economia solidária: a experiência do Banco Palmas

Serpa, Luiz Carlos Moreira da Rocha January 2008 (has links)
SERPA, Luiz Carlos Moreira da Rocha. Geração de trabalho e renda de forma sustentável através da economia solidária: a experiência do Banco Palmas/. 2008. 83f. Dissertação (mestrado profissional) - Programa de Pós Graduação em Economia, CAEN, Universidade federal do Ceará, Fortaleza, 2008. / Submitted by Mônica Correia Aquino (monicacorreiaaquino@gmail.com) on 2013-08-19T20:44:09Z No. of bitstreams: 1 2008_dissert_lcmrserpa.pdf: 294842 bytes, checksum: 12aaf697b65b44f12fa3382fdec973b1 (MD5) / Approved for entry into archive by Mônica Correia Aquino(monicacorreiaaquino@gmail.com) on 2013-08-19T20:44:20Z (GMT) No. of bitstreams: 1 2008_dissert_lcmrserpa.pdf: 294842 bytes, checksum: 12aaf697b65b44f12fa3382fdec973b1 (MD5) / Made available in DSpace on 2013-08-19T20:44:20Z (GMT). No. of bitstreams: 1 2008_dissert_lcmrserpa.pdf: 294842 bytes, checksum: 12aaf697b65b44f12fa3382fdec973b1 (MD5) Previous issue date: 2008 / The work intended to analyze the case of the Bank Palmas as institution of micro-credit that acts in “Palmeiras”, a low-income neighborhood of Fortaleza – CE. According to the work it was showed that the socio-economic policy of micro-credit implemented by the Bank Palmas is capable to generate yield and job for the local population. For the development of this work was intended to deal with articles produced by the Brazilian net of supportive economy, as well like books, field work and matters about the Bank Palmas. From the facts collected in the field work, was used an econometric approach based in the “probit” models and of multiple regression with the objective of analyzing the impacts about the invoicing and the productivity of the companies/clients of the bank Palmas interviewed. The main results of these models are: The aid of the agents of the bank with his clients jointly with the experience of the clients as autonomous shatter of positive form in the invoicing of the companies analyzed, and the loan granted to these companies acts of straight form in the increase of productivity of the same. From that context was concluded that the general objective of the work was reached, therefore, was possible to establish the answers for the problem investigated, arriving to the conclusion of that to economic and social policy of micro-credit developed by the Bank Palmas is straightly related with the generation of income and labor supply of the resident population in Palmeiras. So, it was showed that in the bank there is a strategy of local socio-economic development whose protagonists left of their mere position of inhabitants for the ones of active citizens as collective subjects and that, on average, the loan granted by the bank Palms is of fundamental importance for the growth of the small companies that need the loans from the bank. / O Trabalho pretendeu analisar o caso do Banco Palmas como instituição de micro-crédito que atua no conjunto Palmeiras, bairro de baixa renda da periferia de Fortaleza - Ce. De acordo, com esse trabalho buscou-se mostrar que a política sócio-econômica de micro-crédito implementada pelo Banco Palmas no conjunto Palmeiras é capaz de gerar renda e emprego para a população local. Para o desenvolvimento deste trabalho pretendeu-se trabalhar com artigos produzidos pela rede Brasileira de economia solidária, bem como livros, pesquisa de campo e matérias sobre o Banco Palmas. A partir dos dados coletados na pesquisa de campo, utilizou-se uma abordagem econométrica baseada em modelos de escolha discreta e contínua com o objetivo de analisar os impactos sobre o faturamento e a produtividade das empresas clientes do banco palmas entrevi stadas. Os principais resultados destes modelos são: A assistência dos gestores do banco com seus clientes juntamente com a experiência dos clientes como autônomos impactam de forma positiva no faturamento das empresas analisadas, e o empréstimo concedido a estas empresas atua de forma direta no aumento de produtividade das mesmas. A partir desse contexto conclui-se que o objetivo geral do trabalho foi atingido, pois, foi possível estabelecer as respostas para o problema investigado, chegando-se à conclusão de que a política econômica e social de micro-crédito desenvolvida pelo Banco Palmas está diretamente relacionada com a geração de renda e trabalho da população residente no conjunto Palmeiras, ou seja, mostrar que no Banco Palmas existe uma economia em prática que se vincula à estratégia de desenvolvimento socioeconômico local cujos protagonistas saíram de sua mera posição de habitantes para a de cidadãos ativos como sujeitos coletivos e que, em média, o empréstimo concedido pelo banco Palmas é de fundamental importância para o crescimento das pequenas empresas tomadoras de empréstimos junto ao Banco.
1109

Estratégias competitivas de marketing das empresas panificadoras de pequeno porte diante da concorrência: estudo de caso

Capibaribe, Dulce Eleonora Moreira January 2006 (has links)
CAPIBARIBE, Dulce Eleonora Moreira. Estratégias competitivas de marketing das empresas panificadoras de pequeno porte diante da concorrência: estudo de caso. 2006. 191f. ; Dissertação (mestrado) - Universidade federal do Ceará, Faculdade de Economia, Administração, Atuária, Contabilidade e Secretariado, Fortaleza-CE, 2006. / Submitted by Dioneide Barros (dioneidebarros@gmail.com) on 2016-03-14T17:59:06Z No. of bitstreams: 1 2006_dis_demcapibaribe.pdf: 772272 bytes, checksum: d4c12bff52852a2e7bcddff38834f004 (MD5) / Approved for entry into archive by Dioneide Barros(dioneidebarros@gmail.com) on 2016-03-16T14:20:31Z (GMT) No. of bitstreams: 1 2006_dis_demcapibaribe.pdf: 772272 bytes, checksum: d4c12bff52852a2e7bcddff38834f004 (MD5) / Made available in DSpace on 2016-03-16T14:20:31Z (GMT). No. of bitstreams: 1 2006_dis_demcapibaribe.pdf: 772272 bytes, checksum: d4c12bff52852a2e7bcddff38834f004 (MD5) Previous issue date: 2006 / The competition today has many faces and it has persuaded all kinds of organizations to prepare for the unknown. To broaden your capacity for quick changes or come up with effective and creative initiatives became imperative. Therefore, the choice of strategy and the making of decisions can implicate in the survival of these companies. Our objective is to propose marketing strategies to be used by small bakeries, with a goal to obtain competitive advantages. We emphasize also the study of the strategies adopted by these companies, the comparison of these company’s strategic actions with the theories advocated by the referred authors and the evaluation of these actions in accordance with the company’s positioning. The themes of the theoretical referential that substantiated the field research along with the bakery’s businessmen and managers are associated to the following thematics: strategy and concepts, competitive advantages, strategic positioning and marketing strategy. The characteristics of the local bakeries and the profile of this sector were themes also studied for the better understanding on the subject. The researched companies are traditional bakeries and are of great economical importance for the region where they are installed. The research allowed us to confirm the unawareness of marketing. It was also verified, that the competition between companies of this sector is very aggressive, and that the companies which adopts marketing strategies do so with competitive advantages in mind. In a general way, it was observed that the elevated growth of the economy makes the changes in strategical behavior of the companies mandatory, which suggests a deeper look in to these questions. / A concorrência hoje se apresenta com múltiplas faces e têm persuadido todo tipo de organização a se preparar para o desconhecido. Ampliar sua capacidade de mudanças rápidas ou para tomar iniciativas criativas e eficazes se tornou imperativo. Diante disto, a escolha de estratégias e as tomadas de decisões podem implicar na sobrevivência destas empresas. Temos como objetivo propor estratégias de marketing a serem utilizadas por empresas panificadoras de pequeno porte, com a finalidade de obter vantagens competitivas. Enfatizamos também o estudo das estratégias adotadas pelas empresas em questão, a comparação das ações estratégicas destas com as teorias preconizadas pelos autores referenciados e a avaliação destas ações de acordo com o posicionamento de cada empresa. Os temas do referencial teórico que fundamentaram a pesquisa de campo junto aos empresários e gerentes das panificadoras estão associados às seguintes temáticas: estratégias e conceitos, vantagens competitivas, posicionamento estratégico e as estratégias de marketing. As características das empresas locais de panificação e o perfil do setor de panificação, também foram temas estudados para melhor embasamento sobre o assunto. As empresas pesquisadas são panificadoras tradicionais que representam grande importância econômica para a região onde estão instaladas. A pesquisa permitiu constatar o desconhecimento de técnicas de marketing. Verificou-se, também, que a competição entre as empresas do setor é bastante acirrada, e que as empresas que adotam as estratégias de marketing procuram fazê-lo visando vantagens competitivas. De forma geral, observou-se que o elevado crescimento da economia, torna obrigatória a mudança de comportamento estratégico das empresas o que sugere um aprofundamento destas questões.
1110

Nouvelles méthodologies d'extraction, de fractionnement et d'identification : application aux molécules bioactives de l'argousier (Hippophae rhamnoides) / New extraction, fractionation and identification methodologies : application to sea buckthorn bioactive molecules

Michel, Thomas 23 November 2011 (has links)
La richesse moléculaire des végétaux constitue une source importante de molécules bioactives d‘origine naturelle. La mise en évidence de ces molécules nécessite de nombreuses étapes souvent longues et couteuses. L‘objectif de cette thèse a donc consisté en l‘innovation et le développement de nouvelles méthodologies d‘extraction, de fractionnement et d‘identification de produits naturels d‘origine végétale. Pour cela nous avons utilisé comme modèle végétal l‘argousier (Hippophaë rhamnoides, Elaeagnaceae) qui est un arbuste épineux du plateau Eurasiatique connu pour sa richesse phytochimique et son potentiel thérapeutique. Ce travail a d‘abord conduit au développement d‘une méthode d‘extraction « verte » sans solvant assistée par micro-ondes, basée sur l‘utilisation combinée de la pression, de la température et des micro-ondes. Il a pu être démontré que cette méthodologie permet d‘extraire rapidement et efficacement des composés phénoliques tout en conservant un potentiel antioxydant important. Dans une seconde partie, une nouvelle approche multidimensionnelle couplant la CPC et l‘HPLC-UV-MS a été développée. Cette technique permet la séparation à l‘échelle semi-préparative et l‘identification en ligne des molécules séparées. Il a ainsi pu être identifié par HPLC-MS/MS 3 acides phénoliques et 20 dérivés de flavonols dans l‘extrait micro-ondes sans solvant de baies d‘argousier. L‘activité antioxydante et la cytotoxicité des fractions a également été étudiée in vitro et in cellulo. Enfin la dernière partie de ce travail a démontré le potentiel antioxydant et antimicrobien de différents organes de l‘argousier, qui a été corrélé à la présence flavonoïdes et de proanthocyanidine. L‘intérêt du couplage CPC-HPLC-UV-MS a également été illustré par le fractionnement de deux molécules d‘un extrait actif de racines d‘argousier. / Plant materials constitute an important source of natural bioactive molecules. Characterisation of these molecules requires often multiple, long and expensive development steps. The aim of this PhD thesis consists of innovation and development of new methods of extraction, fractionation and identification of natural metabolites from plants. We used sea buckthorn as plant model (Hippophaë rhamnoides, Elaeagnaceae) an Eurasian thorny shrub known to possess various phytochemical properties and pharmaceutical effects. In the first part of this work a ―green‖ solvent-free microwave assisted extraction, based on the combined use of pressure, temperature and microwave irradiation has been developed. This approach allows fast and efficient extraction of phenolic compounds while maintaining an important antioxidant capacity. In the second part of this work, a new multidimensional approach coupling CPC and HPLC-UV-MS was developed. This technique allows the separation at semi-preparative scale and the online identification of isolated molecules. Using this approach, 3 phenolic acids and 20 flavonols from the solvent free sea buckthorn berries extract were identified by HPLC-MS/MS. Antioxidant activity and cytotoxicity of fractions were studied in vitro and in cellulo. In the last part of this work, the antioxidant and antimicrobial potentials of different sea buckthorn organs, which were correlated to the presence of flavonoids and proanthocyanidins has been demonstrated. The CPC-HPLC-UV-MS technique was also applied to the fractionation and the partial identification of compounds extracted from sea buckthorn root.

Page generated in 0.0311 seconds