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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.
31

Ex situ bevarande : En studie av djurparkers arbete för att bevara biologisk mångfald och turismens förutsättningar för det arbetet / Ex situ conservation : A study of zoos work to conserve biodiversity and tourism conditions to enable zoos work with conservation

Augustsson, Åsa January 2018 (has links)
Bakgrund: Medvetenhet om klimatförändringars påverkan som växt i takt med turismens ökade omfattning har utvecklat ett behov för hållbart resande och en ökad förståelse hos människor om mänskliga aktiviteters negativa miljöpåverkan. Som en utveckling av denna medvetenhet om klimatförändringars påverkan till miljöhot och förlust av biologisk mångfald har djurparker som turistattraktioner fått en allt mer betydelsefull roll. Djurparker, med sina samlingar av djur, har goda förutsättningar för att bevara biologisk mångfald. Djurparker behöver därför bidra till bevarande och djurparkers syfte anses just omfatta bevarande. Tidigare forskning belyser dock att det krävs mer förståelse för vilka bevarandeuppgifter djurparker tar sig an och bidrar med. Syfte och problemformulering: Studiens syfte är att utreda svenska djurparkers bevarandearbete för biologisk mångfald, och besvaras av frågan: På vilka sätt arbetar svenska djurparker med bevarande av biologisk mångfald? Metod: Studien har genomförts utifrån en deduktiv ansats där tidigare forskning har utgjort en grund för studiens forskningsområde. Teoretiska aspekter har testats gentemot studiens empiriska material. Data har samlats in genom telefonintervjuer som genomförts med 19 stycken djurparker belägna i Sverige. Slutsats: Svenska djurparker arbetar med olika bevarandeaktiviteter och i olika stor omfattande grad för att bidra till biologisk mångfald. I samtliga svenska djurparker är djuruppfödning samt information och utbildning de främsta bevarandeuppgifterna. I många djurparker förekommer även arbete med att stödja bevarande in situ, samt att bedriva eller möjliggöra forskningsstudier. Som en förutsättning för bevarandearbetet är turism en betydelsefull faktor eftersom turism bidrar till ekonomiskt stöd och finansiering. Likväl bidrar turism till att besökare kommer till djurparker, vilket är en förutsättning för att djurparker ska kunna sprida information och kunskap som anses vara det mest värdefulla arbetet för att bidra till bevarande av biologisk mångfald.
32

Pathologic Findings and Skin Microbiome Structure of Juvenile Eastern Hellbenders (Cryptobranchus alleganiensis alleganiensis) Under Human Care During a High Mortality Event

Aplasca, Andrea January 2021 (has links)
No description available.
33

Effects of weaning age on body composition and growth of ex situ California sea lion (Zalophus californianus) pups

Davis, Brandon 01 January 2014 (has links)
Pinnipeds exhibit a wide range of lactation strategies that vary from just a few days to nearly three years in duration. Phocids have a relatively short, intense nursing period culminating with weaning after just a few days or weeks, while dependent otariids generally take several months of consuming a combined milk and solid food diet before being completely independent. The transition to nutritional independence can be particularly challenging for newly weaned pups, which must adjust to behavioral, physiological and nutritional changes as a milk diet is replaced with solid food. An interruption in energy resources during this formative stage could result in a prioritization away from growth, maintenance, or activity resulting in suboptimal development. Three groups of ex situ California sea lion (Zalophus californianus) pups were examined during the initial period of independence after they were weaned at approximately five, seven, and nine months of age. Absolute growth rates of pups were calculated and changes in body composition were estimated using blubber depth measurements and deuterium oxide dilution to determine if weaning age had an effect on subsequent pup development and growth. Blood urea nitrogen and blood glucose levels were observed for their response to changes in body condition, while thyroid hormone levels in the blood were examined as a possible nutritional stress indicator during the pup's transition to solid food. When compared to in situ pups, the 5 month old pups in the present study had significantly greater body mass (39.6 ± 1.6 kg, p < 0.01), axillary girth (85.3 ± 2.9 cm, p < 0.01), and axillary blubber depth (2.3 ± 0.1 cm, p < 0.01) compared to 5 month old in situ pups (26.6 ± 5.2 kg / 70.6 ± 5.34 cm / 1.5 ± 0.2 cm). Nine month old ex situ pups had significantly greater axillary blubber depth (3.7 ± 0.9 cm, p < 0.01) and total body lipid percentage (24.9 ± 4.7%, p= 0.01) than in situ pups (1.5 ± 0.2 cm / 17.1 ± 4.9%). Although all pups in the present study survived the transition to solid food, there were apparent differences in how the different age groups responded physiologically. The five month old pups began the switch to solid food with the lowest overall blubber depth (2.6 ± 0.9 cm) and experienced the greatest change in body mass (-8.5 ± 1.6 kg) and composition while taking the longest to begin physiological recovery (31.7 ± 1.2 d). In contrast, the 9 month old pups entered the transition with more energy reserves (24.9 ± 4.7% TBL), began consuming solid food sooner (16.3 ± 0.6 d), and were able to utilize reserves more efficiently to minimize loss and promote faster growth.
34

HYPERSPECTRAL PLANNER INSTRUMENTATION FOR PRODUCT GOAL SYNTHESIS IN MATERIAL PROCESS CONTROL

JACOBS, JOHN DAVID 11 October 2001 (has links)
No description available.
35

Population growth and genetic diversity dynamics of modeled conservation methodologies for threatened plant species

Kashimshetty, Yamini 13 September 2016 (has links)
No description available.
36

« Provincialiser » la Révolution Verte : savoirs, politiques et pratiques de la conservation de la biodiversité cultivée (1943-2015) / “Provincialising” the Green Revolution : knowledges, Policies and Practices in the Conservation of Crop Biodiversity (1943-2015)

Fenzi, Marianna 28 November 2017 (has links)
Le problème de l’accès aux ressources génétiques des plantes pour la sélection variétale est au cœur de la Révolution Verte. A partir des années 1960, les sélectionneurs font de la disparition des variétés locales sous l’effet de la diffusion de nouvelles variétés génétiquement homogènes un problème public à l’échelle mondiale. Dans une perspective qui croise la recherche d’archives et l’enquête de terrain, cette thèse revient sur la formation de ce problème, sur sa trajectoire historique et ses enjeux actuels. Il s’agit d’analyser l’hétérogénéité des savoirs scientifiques et des approches qui sont développés sur le thème de la conservation des ressources génétiques dans les arènes internationales. L’étude des débats et des initiatives menés dans le cadre de la FAO permet de comprendre quels sont les savoirs légitimés, lesquels sont marginalisés et comment la nature et les contours du problème ont été négociés. La place que les ressources génétiques occupent au cours d’épisodes clés de la Révolution Verte est également au cœur de ce travail. Cette thèse analyse spécifiquement l’importance accordée aux variétés locales de maïs dans le programme agricole que la Fondation Rockefeller met en place au Mexique à partir de 1943. Alors que le maïs hybride est généralement présenté comme un vecteur de la modernisation agricole, cette thèse montre que les experts sont confrontés à l’échec du paradigme d’amélioration variétale qu’ils étaient censés exporter. Face à une innovation uniquement applicable à une échelle très limitée, les semences paysannes du maïs restent l’option variétale la plus utilisée au Mexique. Ce travail montre que ce sont bien les choix pragmatiques des agriculteurs qui constituent le fondement de la conservation, de facto, des ressources génétiques du maïs dans ce pays. / The issue of access to plant genetic resources for plant breeding is at the heart of the Green Revolution. Beginning in the 1960s, the disappearance of local varieties with the spread of new genetically homogeneous varieties evolved into a public problem on a global scale. Combining archival research and field investigations, this thesis explores the emergence of this problem, its historical trajectory, and its current forms. I analyze the heterogeneity of scientific knowledge and approaches to the conservation of genetic resources developed in international arenas. An exploration of debates and initiatives within the framework of the FAO sheds light on the issues of which knowledges are legitimated and which marginalized, and on how the nature and outlines of the problem have been negotiated. An examination of the role of genetic resources in key episodes in the Green Revolution is also central to the study. The thesis specifically analyzes the importance attributed to local maize varieties in the agricultural program that the Rockefeller Foundation implemented in Mexico beginning in 1943. While hybrid maize is generally presented as a vector of agricultural modernization, this thesis shows how experts were faced with the failure of the varietal improvement paradigm that they were supposed to export. As hybrid maize is an innovation that is only applicable on a very limited scale, farmers’ maize seeds still are the most widely used varietal option in Mexico. The study shows that it is indeed the pragmatic choices of farmers that form the basis for the de facto conservation of the country’s maize genetic resources.
37

Etude de revêtements photocatalytiques à base de dioxyde de titane nanostructuré élaborés par pulvérisation cathodique magnétron en condition réactive / Photocatalytic coatings based on nanostructured titanium dioxide prepared by reactive magnetron sputtering

Sayah, Imane 17 December 2014 (has links)
Le développement de photocatalyseurs en couches minces supportées constitue un intérêt majeur autorisant une séparation efficace des produits de réaction, en dépit d’une réduction de leur surface spécifique par rapport à des nanopoudres du même matériau. La synthèse de revêtements de TiO2 par pulvérisation cathodique magnétron en condition réactive fait l’objet de recherches intensives. Cette technique permet de contrôler, à travers les paramètres d’élaboration, la structure et les propriétés physicochimiques et photocatalytiques des revêtements.Afin de s’affranchir de la contamination du catalyseur par le sodium du verre lors de traitements en température ou lors de recuits de couches déposées à l’ambiante, une barrière de diffusion en SiNx est intercalée et son épaisseur est fixée pour la suite de l’étude. Différentes couches de TiO2 ont été élaborées à haute pression dans un réacteur doté d’un système de contrôle en boucle fermée basé sur la spectroscopie d’émission optique. L’effet de la cristallisation in situ à différentes températures sur les différentes propriétés des revêtements TiO2 a été étudié et les propriétés de ces derniers ont été comparées à celles des échantillons synthétisés sur des substrats froids et recuits ex situ aux mêmes températures.Enfin, des premiers travaux portant sur l’influence de l’introduction de l’argent en différentes teneurs sur l’efficacité photocatalytique sous lumière visible des couches de TiO2 cristallisées in situ et ex situ sont présentés. / The development of supported photocatalysts thin films is of major interest allowing an efficient separation of the reaction products, in spite of their specific area reduction compared to nanometric scale powders. The synthesis of TiO2 coatings by reactive magnetron sputtering is the subject of intensive researches. This technique allows, trough the control of the deposition parameters, to manage the structure and the physicochemical and photocatalytic properties of the coatings. In order to hinder the sodium contamination of the catalyst from the glass substrate, either during in situ or ex situ heating of the coating, a SiNx diffusion barrier is intercalated with a fixed thickness. Different layers of TiO2 were prepared at high pressure in a reactor equipped with a closed-loop control system based on optical emission spectroscopy. The influence of the in situ crystallization at different temperatures on the properties of the TiO2 coatings was studied. These properties were compared with those of samples synthesized ex situ and at the same temperatures. Finally, first studies on the influence of silver enrichment at different contents on photocatalytic activity under visible light of TiO2 layers crystallized in situ and ex situ, are presented.
38

Análise espacial de populações naturais de Dipteryx alata Vogel. : Subsídio para coleta de sementes /

Lima, Diana Carla de Oliveira Santana January 2016 (has links)
Orientador: Mario Luiz Teixeira de Moraes / Resumo: The spatial distribution pattern of tree species is one of the most important factors for the understanding of the ecological interrelationships occurring in a population or community forestry, it is vital to the understanding of how a certain species uses the resources available to establish and reproduce in a given space. Interpretation of the results of the spatial analysis of tree species provides significant subsidies for the understanding of these phenomena and indication of individuals for genetic conservation programs and forest promotion. In this context, the objective of the work was to study the spatial distribution of six natural populations of arborea specie baru (Dipteryx alata Vogel.) using the Moran index associated with a Geographic Information System and descriptive statistics of their silvicultural attributes. These populations are located in the municipalities of Paulo de Faria/SP, Campina Verde/MG, Ituiutaba/MG, Brasilândia/MS, Campo Grande/MS e Itarumã/GO. All populations had a growth over 45 cm in relation to the DAP (Diameter at Breast Height) attribute. Taking into account that the DAP attribute has a higher dendrochronological correlation, the estimated age of these natural populations would be in the range between 40 and 63 years. As regards the calculation of Moran index, populations of Ituiutaba and Itarumã presented random spatial distribution pattern, pointing high variability among its individuals, so the collection of seeds for ex situ conserv... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre
39

Conhecimento local, diversidade morfo-genética como subsídios para conservação da mangaba / Local knowledge, morphological and genetic diversity as subsidies for conservation mangaba

Freitas, Bruno Antonio Lemos de 26 February 2016 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / One of the challenges in the conservation of genetic resources is the identification of areas for collection, maintenance and preservation of seeds, especially recalcitrant, for in situ and ex situ conservation. Thus, through four articles is intended to identify areas with potential naturally occuring mangaba using modeling techniques by Maxent software using environmental variables, as well as to characterize the morpho-genetic diversity using local and scientific knowledge by the analysis of fruits, and conservation of seeds in order to guarantee the viability in the storage. It is observed distribution of populations intensively on the coast, with higher occurrence in the municipalities of Greater Aracaju and Japoatã, Pacatuba, Nossa Senhora das Dores, Malhador, Estancia, Arauá and Itabaianinha. To evaluate the traditional knowledge of the catchers of mangabas inserted into remaining forests, five associations were selected (Baixa Grande, Pontal, Porteiras, Riboleirinha and Manuel Dias). It was observed that the classification of fruit occurs according to color and there are differences among the collection locations for morphometric and physical- chemical (pH, titratable acidity, soluble solids) traits. Baixa Grande seeds (Pirambu-SE) were stored at 10 ° C in polyethylene glycol 6000 to -0.8 MPa and it was observed that viability can be maintained until the third month. Four natural population (111 individuals) were evaluated by of molecular markers ISSR. The population of Baixa Grande presented the highest number of observed and effective alleles (1.99 and 1.61). The number of polymorphic loci was 71 (95% Polymorphism). The differences in morphological characteristics of mangaba can be used for selection of genotypes. The information resulting from this research are subsidies for management and conservation aiming to increase the diversity of mangaba in the state of Sergipe. / Um dos desafios na conservação dos recursos genéticos é a identificação de áreas para coleta, manutenção e preservação de sementes, especialmente as recalcitrantes, visando à conservação in situ e ex situ. Assim, por meio de quatro artigos, se propõe identificar regiões com potencial ocorrência natural de mangaba por meio de técnicas de modelagem pelo programa Maxent empregando variáveis ambientais, bem como caracterizar a diversidade morfo-genética empregando o conhecimento local e científico por meio da análise de frutos, e conservar as sementes de forma a garantir a viabilidade no armazenamento. Observa-se a distribuição das populações mais intensamente no litoral, com maior ocorrência nos municípios da Grande Aracaju e Japoatã, Pacatuba, Nossa Senhora das Dores, Malhador, Estância, Arauá e Itabaianinha. Para avaliar o conhecimento das catadoras de mangabas inseridas em remanescentes florestais, foram selecionadas cinco associações (Baixa Grande, Pontal, Porteiras, Riboleirinha e Manuel Dias). Observou-se que a classificação dos frutos ocorre de acordo com cor e diferenças entre as localidades de coleta para características morfométricas e físico-químico (pH, acidez titulável, sólidos solúveis). Sementes de mangaba de Baixa Grande (Pirambu-SE) foram armazenadas à 10ºC em polietilenoglicol 6000 à -0,8 MPa e constatou-se que a viabilidade pode ser mantida até o 3° mês. Quatro populações naturais de mangaba (111 indivíduos) foram avaliadas por meio de marcadores moleculares ISSR. A população de Baixa Grande foi a que apresentou maior número de alelos observados e efetivos (1,99 e 1,61). O número de locos polimórficos foi de 71 (95% de polimorfismo). As diferenças observadas nas características morfológicas de mangaba podem ser utilizadas para a seleção de genótipos. As informações resultantes desta pesquisa são subsídios para manejo e conservação visando ampliar a diversidade de mangaba no estado de Sergipe.
40

Evaluation of IN SITU synthesis route of layered hydroxides in the presence of amphiphilic polymers in comparison with their corresponding physical mixtures / Evaluation d'une voie de synthèse IN SITU d'hydroxydes lamellaires en présence de polymères à caractère amphiphiles en comparaison avec leurs mélanges physiques correspondants

Langry, Arthur 07 October 2015 (has links)
L’originalité du manuscrit de thèse est basée sur une preuve de concept selon laquelle il peut être possible de générer IN SITU des matériaux plaquettaires au sein même d’une matrice polymère à renforcer. Cette approche est basée sur une nouvelle voie de préparation de matériaux hybrides à base d’hydroxydes lamellaires. Cette méthode combine une voie de synthèse par polyol et la génération IN SITU de plaquettes inorganiques, en présence d’oligomères BOLA à caractère amphiphile. La voie polyol consiste en l’hydrolyse en milieu alcoolique d’un ou de plusieurs sels acétate métalliques comme précurseur, en vue de former les phases LSH et HDL suivantes, LSH-Zn, LDH-Zn2Al ;-LiAl2. Les BOLA possèdent des segments téléchéliques composés de chaînes hydrophobes terminées par deux groupes anioniques hydrophiles, l’ensemble est neutralisé par un cation ammonium. L'impact de la voie de synthèse IN SITU, les systèmes plaquettaires choisis ainsi que les contre-ions organiques à partir de la morphologie des phases hybrides obtenues, est étudié en comparaison aux mélanges physiques correspondants (EX SITU). Ce manuscrit présente une étude structurale des différents nanocomposites formés ; par le biais d’analyses DRX, complétées par du SAXS (ligne de lumière SWING à Soleil) et de l’imagerie MET. Des bilans matière sur les différentes synthèses IN SITU sont aussi réalisés pour déterminer les rendements de formation et taux de conversion des précurseurs en matériaux lamellaires. Concernant l’approche EX SITU ; les chaines polymère diffusent entre les plaquettes inorganiques, ceci principalement lié à une réaction d’échange entre les anions acétate des phases lamellaires et les fonctions carboxylates des chaines polymère, conservant l’intégrité des feuillets à par un processus topotactique. L’efficacité du processus d’intercalation a été trouvée décroissante suivant LDH-Zn2Al > LDH- LiAl2 >> LSH-Zn. Dans le cas du LSH-Zn, un ensemble stratifié à plusieurs échelles a été observé alliant charpente inorganique initiale intercalé acétate et une partie diffusée du BOLA, conduisant à une structuration dite biphasique. Contre intuitivement, dans le cas des HDL, la voie EX SITU, basée sur la réaction topotactique d'échange, et la voie IN SITU, basée sur la réaction de templating ont donné dans de nombreux cas des résultats similaires en terme d'états de dispersion, et ceci indépendamment du polymère ou du BOLA utilisé ainsi que de la composition des plaquettes. L’observation de plaquettes isolées LSH-Zn, n’a jamais été reportée dans la littérature, ce qui rend alors le processus de synthèse polyol/IN SITU intéressant pour l’obtention d’état de dispersion exfolié pour ce type de particules. La combinaison polyol/IN SITU permet la génération de plaquette LSH ou LDH de taille latérale comprise entre 10 à 200 nm. Cependant, les plaquettes générées se sont révélées poreuses, un inconvénient pour les propriétés de type barrière. Ce résultat ouvre toutefois des perspectives nouvelles en intégrant ces plaquettes 2D poreuses avec des particules de type 1D pour une approche en architecture « tectonique ». / Layered particle based nano-composites have recently been shown to impart stone impact resistance to automotive coatings by making use of polymer intercalated Layered Double Hydroxide (LDH) platelets in a variety of different film morphologies. However the LDH particles used were obtained via coprecipitation of the metal salts in the presence of small organic anions in order to render the Layered Hydroxide particles organophilic and to facilitate the intercalation of carboxylate group bearing matrix polymers. Thus anion exchange in the course of colloidal processing and during film formation leads to the release of ionic species which may deteriorate the coatings barrier function. In order to circumvent objectionable counter ions (involved in the synthesis and the coatings formulation), a novel preparation route for layered hydroxide based hybrid phases has been here investigated combining the polyol route with the IN SITU generation of inorganic platelets, in the presence of amphiphilic polymer as well as bola-amphiphiles. The polyol route consists in hydrolysis in an alcoholic medium containing acetate metal cation as precursor(s), to yield LDH (Zn2Al, LiAl2 cation composition) or LSH-Zn (Layered Single Hydroxide). Bola amphiphile descripts as being some hydrophobic polymer segment-telechelic-chains terminated by two anionic hydrophilic end groups, using of volatile ammonium cation as counter ion. The impact of both process conditions as well as the chosen system with regard to the metal hydroxide framework and the organic counter ions on the morphology of the obtained hybrid phases are presented, discussed and compared to corresponding physical mixture. For the EX SITU approach, the diffusion of large cumbersome polymers or amphiphilic bolas between the inorganic platelets was found to be efficient, mostly driven by an anion exchange reaction between interleaved acetate anions and carboxylate functions of the molecular backbones, and keeping intact the inner-sheet integrity through a topotactic process. The efficiency of the intercalation process was found decreasing to range as LDH-Zn2Al > LDH-LiAl2 >> LSH-Zn, more or less regardless of the guest organic species. Aggregation may happen and cannot be discarded especially when using LiAl2 type platelets and non-neutralized bola. In particular with LSH-Zn, a multi stratified assembly has been observed combining acetate pristine structure and partly bola diffused structure, leading to a biphasic structure, aggregated and intercalated. To the best of our knowledge, observation of LSH-Zn single platelets has never been reported, making of the combined process Polyol/IN SITU an interesting new route in reaching exfoliation. Indeed, it yields to the generation of platelets either LSH or LDH of lateral size ranging between 10 up to 200 nm. However, the platelets were found to be porous; it is considered as a drawback for barrier properties. It is our belief that such porosity may open new insights in “tectonic” architecture by intertwining 2D and 1D-type filler. Rather counter intuitively, EX SITU based on topotactic exchange reaction matches the IN SITU templating reaction in many cases as a function of the dispersion state regardless of the polymer or bolas as well as the platelets cation composition.

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