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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.
61

Embryonic development and effects of environmental factors on the pre-mature hatchling of Sepia pharaonis

Lin, Chun-yen 10 September 2009 (has links)
Pre-mature hatching of fertilized eggs of cuttlefishes and squids, which are Taiwan¡¦s major fishing species, exists in the late embryonic development before yolk sacs are fully absorbed. It is so far unknown whether there is any difference in survival rate between pre-maturely developed juveniles and the fully developed ones. Hence, by laboratory incubation, this study aimed to discuss the relationship between the yolk size in the embryonic development process and embryo, as well as the difference in survival rate of juveniles developed at different developmental stages. The impact of the incubation time on the survival rate is explored in case of changing physical and chemical environmental factors (temperature, salinity, ammonia concentration, vibration etc.) The embryonic development of Sepia pharaonis can be divided into 40 stages according to the external shape and quality of the embryo. The embryo mantle length and the yolk diameter vary by time, while the increasing rate of the mantle length does not(F = 1.88, p = 0.06), increasing or decreasing in a linear relationship respectively. However, under the same environmental conditions, the consumption rate and the mantle size may vary in different batches(yolk diameter: F = 8.77, p < 0.01. mantle length: F = 92.14, p < 0.01). There is no difference in the surviving time of juveniles artificially and naturally incubated at the same developmental stage, and the surviving time will be longer if the artificially incubated juveniles are at later embryonic developmental stages(F = 34.66¡Ap < 0.01). With regard to the feeding ratio of juveniles pre-maturely hatched at different stages, the feeding ratio of the juveniles incubated after the 36th stage will increase with the developmental stages(F = 93.10¡Ap < 0.01). In this study, the temperature limit of the embryonic development of Sepia pharaonis should never be lower than 10¢J or higher than 35¢J, and the most suitable temperate range is between 17-28¢J. In case of sudden change in temperature, temperature increase can more effectively affect the pre-mature hatching than temperature decrease. In case of either the 36th or 39th stage embryos, if the temperature rises or drops by more than 10 degrees, pre-mature hatching can exist in some of the embryos. Some embryos may die if salinity is lowered suddenly below 20 psu. Meanwhile, pre-mature hatching may occur within one hour if it is suddenly lowered below 10 psu, and the unhatched embryos may die. When increasing the ammonia concentration suddenly to 1 and 5 ppm, the embryo incubation time may be lengthened compared with the group without the addition: some embryos may die if it is increased to 5 ppm. Meanwhile, most embryos are hatched pre-maturely within 17 minutes when it is increased to 1000 ppm, while those unhatched ones may die. In case of various environmental stimuli of the experiments, a higher percentage of embryos at the 39th stage got away from the hostile environment by pre-mature hatching, while a higher percentage of embryos at 36th stage continued the development until natural incubation or died. The vibration experiment is to produce vibration by a vertical vibration instrument. In case of 30-minute vibration at frequency of 350 times/minute and maximum amplitude at 2 cm, there is no effect on incubation time and mode of embryos at both stages. This factor is still open and subject to further discussion.
62

Contributions à la compréhension de problèmes d'optimisation combinatoire et études d'extensions de la méthode B

Poirriez, Vincent 06 December 2006 (has links) (PDF)
Je présente dans ce mémoire un bilan de mon activité scientifique effectuée au sein des groupes POC (Parallèlisation et Optimisation Combinatoire) et SID (Systèmes d'Information Distribués) de l'équipe ROI (Recherche Opérationnelle et Informatique) du laboratoire LAMIH à l'UVHC. <br /><br />Mes travaux de recherche se divisent en trois parties:<br /><br /> - l'étude du problème du sac-à-dos non borné, problème classique de l'optimisation combinatoire, dont nous mettons en évidence des propriétés fondamentales et pour lequel nous avons dérivé, implanté et mis à disposition deux algorithmes qui tirent avantage des propriétés découvertes;<br /><br /> - une approche algorithmique parallèle/distribuée pour la<br /> bio-informatique notamment le problème de repliement de protéïnes qui est un problème reconnu comme l'un des plus difficiles posés à la science informatique dans le contexte de la bio-informatique;<br /><br /> - le développement d'une plate-forme ouverte d'expérimentations pour la méthode formelle B, l'étude de la modularité du langage B et d'extensions de B pour générer des composants logiciels ainsi que l'étude de l' adjonction au langage B d'une logique temporelle.<br /> <br /> Nous montrons comment les approches utilisées dans une recherche en optimisation combinatoire d'une part et en spécification formelle d'autre part peuvent s'enrichir et se féconder mutuellement.
63

Contribution à la programmation en nombre entier

Boyer, Vincent 14 December 2007 (has links) (PDF)
Le problème du sac à dos à plusieurs contraintes est un problème classique de l'optimisation appartenant à la classe des problèmes NP-difficiles. On le retrouve notamment sous la forme de sous-problème de nombreux problèmes d'optimisation combinatoire. Les méthodes classiques de résolution exacte telles que la programmation dynamique ou le branch-and-bound ont été traitées abondamment dans la littérature. Elles présentent n'eanmoins des faiblesses si elles sont utilisées telles quelles, d'où l'idée de faire coopérer ces méthodes en tirant profit de leurs spécificités afin de proposer soit des méthodes heuristiques performantes, soit des méthodes exactes plus efficaces. Les approches heuristiques que nous proposons sont comparées à d'autres heuristiques de la littérature. Notre méthode coopérative est, quant à elle, comparée à un algorithme de branchand- bound. L'ensemble de ces tests numériques ont été menés pour diverses instances plus ou moins difficiles de la littérature ainsi que sur des instances engendrées aléatoirement. Enfin, nous proposons deux techniques pour engendrer des problèmes difficiles. Ces dernières sont basées sur des problèmes en contraintes égalités et sur l'analyse de la transformée en Z du sac à dos.
64

Optimisation multi-objectif par colonies de fourmis : cas des problèmes de sac à dos

Alaya, Inès 05 May 2009 (has links) (PDF)
Dans cette thèse, nous nous intéressons à l'étude des capacités de la méta heuristique d'optimisation par colonie de fourmis (Ant Colony Optimization - ACO) pour résoudre des problèmes d'optimisation combinatoire multi-objectif. Dans ce cadre, nous avons proposé une taxonomie des algorithmes ACO proposés dans la littérature pour résoudre des problèmes de ce type. Nous avons mené, par la suite, une étude expérimentale de différentes stratégies phéromonales pour le cas du problème du sac à dos multidimensionnel mono-objectif. Enfin,nous avons proposé un algorithme ACO générique pour résoudre des problèmes d'optimisation multi-objectif. Cet algorithme est paramétré par le nombre de colonies de fourmis et le nombre de structures de phéromone considérées. Il permet de tester et de comparer, dans un même cadre,plusieurs approches. Nous avons proposé six variantes de cet algorithme dont trois présentent de nouvelles approches et trois autres reprennent des approches existantes. Nous avons appliqué et comparé ces variantes au problème du sac à dos multidimensionnel multi-objectif
65

ES biologinės įvairovės apsaugą užtikrinančių teisės aktų įgyvendinimas Lietuvoje (šikšnosparnių apsaugos pavyzdžiu) / Implementation of the Law Acts in Lithuania that Vouch European Union Biodiversity Protection (The Example of the Bats Protection)

Šaltenytė, Aušra 05 January 2007 (has links)
Nowadays great attention is payed to the protection of the biodiversity not only in the EU but also in the whole world. The wane of the biodiversity was influenced by the intensive use of the natural resources and the decimation of the natural landscape. This process has become very fast and often irreversible. According to the protection of the biodiversity, the five international conventions have been signed: Ramsar Convention, Rio de Janeiro Convention, Washington Convention, Bonn Convention, Bern Convention. Lithuania has ratified all of them. Now Lithuania has a very important task to fulfil all the obligations and requirements. The most important obligation is to establish the Natura 2000 territories network. Though the requirements of the directives have been started implementing since 1999, the process still continues. The SPAs status has already been given to 77 localities and 299 are the SAC potentials. There are 12 territories that are intended for the bat protection in the SAC potentials register. Great concern has been showed to the protection of these animals in Europe. On purpose to give it a better protection 31 European countries have ratified the Agreement on the Conservation of Population of European Bats (EUROBATS). Lithuania signed it in 2001. The aim of the work is to study how successfully Lithuania deals with the main 8 obligations. The obligations are: the prohibition of the deliberate catching, keeping and killing, the protection of bats converts... [to full text]
66

Incubation biology of the Australian Brush-turkey (Alectura lathami)

Yvonne Eiby Unknown Date (has links)
Temperature is arguably the most important abiotic factor influencing the embryonic development in ectothermic species. Incubation temperature has demonstrated effects on offspring phenotypes in ectotherms, including traits such as sex, size, shape, colouration and post-hatch growth and survival. However, in endotherms the influence temperature has on development is relatively unexplored due to the narrow range of temperatures that embryonic endotherms are exposed to during develop. Megapode birds utilize environmental heat sources to incubate their eggs and therefore provide a potential model to test how temperature influences embryonic development and offspring phenotypes in endotherms. I used the Australian Brush-turkey (Alectura lathami), a megapode bird that incubates its eggs in mounds of soil and leaf litter to investigate the effects of temperature on embryonic development and chick morphology. Previous reports of Australian Brush-turkey incubation mound temperatures relied on spot measurements and theoretical modeling and thus have not provided a comprehensive examination of the range of temperatures Brush-turkey embryos are exposed to and how these might vary during the course of incubation. Therefore to examine the range of temperatures experienced by developing embryos I continuously recorded the temperature of eggs and mound material at naturally occurring positions within incubation mounds over the full developmental period. As in previous studies I found the average incubation temperature to be about 34°C, however egg temperatures typically fluctuated more than previously reported or predicted from modeling. The thermal tolerance of Brush-turkeys is remarkable compared to non-megapode birds, with embryos developing successfully despite prolonged exposure to sub-optimal temperatures over the range 25-40°C. I also demonstrated that the incubation period was negatively correlated with mean incubation temperature. To simplify the examination of temperature effects on embryonic development, constant temperature artificial incubation of Brush-turkey eggs was used to determine influence of incubation temperature on the energetics of embryonic development and the sex ratio, morphology and chemical composition of chicks. Because initial investigation of mound temperatures determined the mean incubation temperature in Brush-turkeys to be 34°C this was used as the preferred temperature for constant temperature incubation with 32°C and 36°C representing low and high temperatures respectively. Previously, the sex ratio of Brush-turkey chicks at hatching was shown to be temperature dependent. A thermally sensitive period early in development resulted in more females hatching from high temperature and more males hatching from low temperatures with an equal ratio at the preferred temperature. Using molecular sexing techniques to determine the sex of both failed embryos and chicks that hatched, I established that at laying the sex ratio of eggs was 50:50, and that temperature-dependent sex-biased embryo mortality was the mechanism behind the skewed sex ratio of chicks hatching from non-preferred temperatures. Low incubation temperature increased female embryonic mortality and high incubation temperature increased male embryonic mortality. This represents a novel mechanism operating to alter sex ratios in a bird species and offers an unparalleled system to explore sex allocation theory. It is well established that temperature influences the rate of development and the morphology of offspring in reptilian species. Also, in a previous study using artificially incubated Brush-turkey eggs, temperature was found to affect the mass of chicks but not their size (linear dimensions). This finding suggests that at different incubation temperatures the amount of yolk converted into tissue during embryonic development is influenced by incubation temperature. I tested this hypothesis by incubating eggs at different constant temperatures and found high incubation temperatures produce chicks with lighter yolk-free bodies and heavier residual yolks but similar linear dimensions compared to chicks hatching from lower temperatures. Because eggs incubated at low temperatures have longer incubation periods, I hypothesized the proportion of lipid in the yolk-free body would be higher in chicks emerging from eggs incubated at low temperature because more time is available for the conversion of yolk to fat bodies during embryonic development. This hypothesis was not supported as the composition of yolk-free chicks (total water, lipid, protein and ash) was not temperature dependent. A previous study in Malleefowl (Leipoa ocellata), another megapode bird, found that the total energetic cost of production was influenced by incubation temperature. Such that embryos developing at low temperatures required 72% more energy than embryos developing at high temperatures. However these findings were contrary to expectation from studies of reptilian incubation where the energetic cost of development is independent of temperature. Therefore I tested the hypothesis that the total energetic cost of development is temperature dependent in the Australian Brush-turkey. I used bomb calorimetry to measure the energy content of freshly laid eggs and of chicks (both the yolk-free body and residual yolk) that had hatched from eggs incubated 32oC, 34oC and 36oC. I found that the total energy content of chicks at hatching was greater in chicks emerging from eggs incubated at 34oC and 36oC compared to eggs incubated at 32oC. My thesis work demonstrated that incubation temperature is more variable for Brush-turkey embryos than for non-megapode birds and that even a small difference in temperature can have important effects on chick sex ratios, morphology and energy reserves. I have shown that incubation under artificial constant temperature conditions can significantly alter the developmental trajectories and phenotypic outcomes for chicks. In addition to laboratory based work, future studies should continue to examine how embryonic development and chick attributes are influenced by temperatures experienced under natural incubation conditions. Furthermore, investigation is required to determine how incubation temperature induced differences in hatchling phenotypes influence the post-hatch grow and fitness of chicks.
67

The round window membrane - gateway to the cochlea : a morphological and electrophysiological study /

Nordang, Leif, January 2002 (has links)
Diss. (sammanfattning) Uppsala : Univ., 2002. / Härtill 5 uppsatser.
68

Aprimoramento do modelo F-SAC para aplicação na descrição de líquidos iônicos

Schneider, Rafael January 2018 (has links)
Os líquidos iônicos são uma das principais apostas para revolucionar a química no século XXI. Em geral, apresentam propriedades como baixa pressão de vapor, alta estabilidade térmica, e ampla existência liquida e outras que os tornam interessantes para aplicações como solventes para extração, meio reacional e como meio catalítico. Estas propriedades permitem a redução da geração de efluentes industriais, o que os torna potenciais solventes verdes. O interesse recente aumentou a quantidade de ânions e cátions disponíveis para formar líquidos iônicos. Essa maior diversidade por um lado aumenta o potencial de aplicação industrial dos líquidos iônicos, mas por outro aumenta a carga de trabalho para obter as propriedades necessárias para projeto industrial destas novas substâncias. Métodos preditivos podem ser utilizados para evitar a grande demanda de ensaios experimentais para obter essas propriedades. Entretanto modelos puramente preditivos, como o COSMO-RS, usualmente não obtém uma acurácia adequada para o uso industrial. Modelos que fazem uso de dados experimentais de misturas para estimar seus parâmetros, como o UNIFAC (Do) e o F-SAC, são predominantes na indústria. Esses modelos, que são modelos de coeficiente de atividade, permitem o cálculo de equilíbrio de fases e outras propriedades termodinâmicas. Este trabalho teve como objetivo o desenvolvimento do modelo F-SAC para líquidos iônicos. Baseado em trabalhos anteriores, foram reestimados os parâmetros dos grupos de líquidos iônicos já existentes e adicionados novos grupos de cátions e ânions. Também foram geradas as primeiras curvas de equilíbrio líquido-vapor de misturas contendo líquidos iônicos com o F-SAC. De forma geral, para os 1-alquil-3-etil-imidazólios, foi obtido um R2 de 0.9794 e o valor de AAD de 0.1721 para 1514 misturas com o modelo F-SAC, superior ao encontrado para o UNIFAC (Do). Para o piridínio e o pirrolidínio o F-SAC obteve, respectivamente, um R2 de 0.9281 e 0.9837 e um valor de AAD de 0.2749 e 0.0962. Com este trabalho é possível formar 24 diferentes líquidos iônicos base com o uso de 33 parâmetros eletrostáticos estimados e 22 parâmetros geométricos no F-SAC. Para o mesmo objetivo o modelo UNIFAC (Do) necessitaria de 180 parâmetros binários e 26 parâmetros individuais – todos estimados. Ou seja, o F-SAC, nesse caso, precisou estimar apenas 27% do número de parâmetros que o UNIFAC (Do). / Ionic Liquids are one of the most promising fields to revolutionize chemistry in the 21st century. In general, they show properties like negligible vapor pressure, high thermal stability, wide liquid existence turn them interesting for applications as solvents for extraction, as reactional and catalytic media. These properties allow a reduction in industrial effluent production, making them eligible green solvents. Recent inteerest expanded the number of anions and cations available to compose Ionic. This great diversity enhances the industrial application potential of Ionic Liquids, while increases the workload needed for obtaining properties of these new substances needed for industrial project. Predictive methods can used to avoid the demand of experiments to obtain these properties. Purely predictive methods, as COSMO-RS, are usually not accurate enough for industrial use. Models use experimental data from mixtures for parameter estimation like UNIFAC (Do) and F-SAC, are predominant in the industry. Activity coefficient models like these allow the solving of phase equilibria and other thermodynamic properties. This work aimed at developing the F-SAC model for Ionic Liquids. Based on previous works, the already existing parameters for Ionic Liquid groups were reestimated and new cation and anion groups were added. In addition, the first vapor-liquid equilibrium curves for mixtures containing Ionic Liquids were created for the F-SAC model. For 1-alkyl-3-ethyl-imidazoliums, an overall R2 of 0.9794 and AAD of 0.1721 for 1514 mixtures was obtained, superior to UNIFAC (Do) values. For pyridinium and pyrrolidinium, F-SAC achieved, respectively, R2 of 0.9281 and 0.9837 and AAD of 0.2749 and 0.0962. With this work is possible to form 24 different base Ionic Liquids with 33 estimated electrostatic parameters and 22 geometric parameters with F-SAC. For the same purpose, UNIFAC (Do) would need 180 binary parameters and 23 individual parameters – all estimated. For this particular case the F-SAC model needed to estimate only 27% of the parameter number UNIFAC (Do) needed.
69

Culture et langue : les séquelles de l'esclavage sur la société réunionnaise contemporaine, illustré par le film Sac la mort.

Folio, Lucie 22 March 2018 (has links)
Bien que l’esclavage ait été aboli en France il y a maintenant plus de 150 ans, la domination de l’Empire français subie par les diverses colonies, a laissé des traces visibles sur les populations de ces dernières. Par son oppression, sa violence physique et psychologique, et l’imposition d’un modèle occidental à suivre, la colonisation a laissé derrière elle des peuples vidés de leur culture, de leur langue et de leur identité. En 2017, un film d’Emmanuel Parraud, intitulé Sac la mort, sera la parfaite illustration cinématographique de cette situation postcoloniale sur l'Île de la Réunion. S’appuyant sur les théories de la pensée postcoloniale, le réalisateur parvient à mettre en images cette “aliénation du Noir colonisé”, théorie développée par Frantz Fanon dans son œuvre Peau noire, masques blancs, selon laquelle l’ancien colonisé est devenu un être étranger à lui-même, ayant adopté la culture et la langue du colonisateur. Mais, au-delà de cette aliénation, se cache surtout une véritable souffrance psychologique; une souffrance qui ronge de l'intérieur ces anciens colonisés, qui les empêche d’avancer, les ancre à leur passé d’esclaves, et qui, surtout, les détruit à petit feu. Malgré cette triste réalité, parfaitement dépeinte dans Sac la mort, l’auteur parvient à nous offrir la vision d’espoir, par les réunionnais, d’un avenir meilleur. Les réunionnais, tout comme tous ces anciens colonisés de Guadeloupe, de Martinique ou d’Afrique, prennent conscience de leur valeur et veulent se réapproprier et défendre leur culture, leur langue et leur identité qui leur ont été jadis volées.
70

Plan de negocios para la comercialización de productos de la marca {de guste} en las regiones con mejores condiciones económicas y sociales del Perú

Herrera Valladares, Luz Maritza, Martínez Tarazona, Anderson Osneister, Palza Bernuy, Augusto Carlos 01 July 2017 (has links)
El presente plan de negocio consiste en evaluar la factibilidad para la comercialización de productos orgánicos de la marca {DE GUSTE} en el mercado local (Perú). En este contexto, se plantea la constitución de la empresa Comercializadora Los Andes SAC, como una oportunidad de negocio, para inicialmente comercializar de manera exclusiva en el mercado peruano, los productos orgánicos de la marca {DE GUSTE}, los cuales son producidos por la empresa peruana De Guste Group SAC líder en el mercado de procesamiento y exportación de granos andinos como la Quinua, Kiwicha, Cañihua y Chia, así como superfoods 100% orgánicos. La cercana relación entre los socios de Comercializadora Los Andes y la empresa De Guste Group ha hecho posible la negociación de la comercialización y distribución exclusiva de los productos de la marca {DE GUSTE} en el mercado peruano por parte de Comercializadora Los Andes, empresa liderada por socios y/o accionistas con diferentes formaciones y experiencia en diversos campos y sectores de la industria, permitiendo así cubrir las necesidades del área comercial, operaciones, administración y recursos humanos, facilitando el camino para llegar a mejores resultados con una labor conjunta. La ventaja competitiva de Comercializadora Los Andes es ofrecer productos orgánicos certificados tales como granos andinos, así como sus derivados, caracterizados por contar con garantía de calidad avalada por los sellos internacionales (BRC, HACCP, KOSHER, ORGANICOS EU, NOP, JAS, BIOSUISSE, COR, GLUTEN FREE) con los que cuentan los productos de la marca {DE GUSTE}, Para comprender mejor el mercado y al consumidor, se ha realizado un estudio en las tres principales regiones, según las condiciones económicas y sociales del Perú (Lima, Arequipa, Moquegua), el cual nos reveló la disposición cada vez mayor de compra de alimentos orgánicos. Asimismo, el estudio realizado ayudó también a definir el perfil de cliente objetivo final. Inicialmente se ha previsto como objetivo capitalizar como clientes a los principales operadores de supermercados (distribución masiva), mayoristas de productos, tiendas orgánicas, hoteles y restaurantes de las ciudades ubicadas dentro de las regiones antes seleccionadas, ubicadas dentro de las regiones antes seleccionadas. Asimismo, para como estrategia de fidelización de clientes se mantendrán comunicaciones constantes con la finalidad de asegurar y recibir la retroalimentación de su satisfacción y se proporcionará servicios de comercialización personalizados en base a sus patrones de compra identificados. Para la puesta en marcha de la empresa, se tendrá la necesidad de implementar instalaciones (oficinas de ventas, almacenes), así como equipos, maquinaria (montacargas, elevadores) y vehículos para el transporte y distribución. La inversión inicial requerida es de S/. 3,099,257.96, y la proyección de venta es de S/. 10,192,003.89 soles para el primer año, con una tasa de crecimiento anual de ventas del 6%. Finalmente, luego de realizado el análisis financiero se concluye que el plan de negocio es rentable para los accionistas pues aparte de recuperar la inversión en 3.11 años y obtener rentabilidad demostrada con la tasa interna de retorno económica (TIRE) de 32.13% y la tasa de retorno financiera (TIRF) de 39.42%, agrega valor en S/. 1,346,461.91 para el caso del VAN Económico y S/. 1,310,620.86 en el caso del VAN Financiero, (para ambos casos se consideró una tasa esperada de rentabilidad para el accionista del 19%). / Trabajo de investigación

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