• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 52
  • 34
  • 13
  • 9
  • 5
  • 3
  • 1
  • 1
  • 1
  • Tagged with
  • 126
  • 15
  • 14
  • 12
  • 10
  • 8
  • 8
  • 8
  • 7
  • 7
  • 7
  • 7
  • 6
  • 6
  • 6
  • 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.
71

De la génétique des populations à la gestion durable des résistances : intérêt de l'étude des populations sauvages des pathogènes des cultures. Cas de deux nématodes à kystes et de leur hôte sauvage commun / From population genetic to sustainable management of resistances : benefit of the study of wild populations of crops pathogens. Case of two cysts nematodes and their common wild host

Gracianne, Cécile 10 April 2015 (has links)
La gestion durable des variétés génétiquement résistantes aux pathogènes des cultures nécessite de tenir compte de leurs capacités évolutives. Celles-ci découlent de leur histoire évolutive et de la dynamique actuelle de leurs populations qui peut être modifiée par les activités humaines inhérentes au milieu agricole. La description et l’évaluation des capacités évolutives d’un pathogène ne sont donc possibles que sur des populations issues d’environnements non soumis à des perturbations d’origine anthropique. Les objectifs de ce travail sont donc (1) de reconstruire les histoires évolutives de deux nématodes à kystes, Heterodera schachtii et Heterodera betae et de leur hôte sauvage commun, Beta vulgaris ssp. maritima, à partir de populations sauvages distribuées sur le littoral du sud de l’Espagne à la Suède ; (2) de décrire, à une échelle plus fine, le fonctionnement et la structure génétique de populations sauvages d’H. schachtii.Nos résultats montrent que la colonisation de la côte Atlantique par les deux nématodes a probablement été influencée par les fluctuations climatiques survenues depuis le dernier Maximum Glaciaire et les courants marins. Les patrons phylogéographiques observés entre H. schachtii et la plante suggèrent des histoires évolutives disjointes contrairement à ceux observés chez H. betae. A fine échelle spatiale, les populations d’H. schachtii sont isolées entre elles, structurées à l’échelle de la plante hôte et présentent de petites tailles efficaces. Ces résultats sont discutés dans le contexte général de la protection des cultures. / The sustainable management of genetic resistances to crop pathogens needs to consider their evolutionary potential. The evolutionary potential results both from the evolutionary history and the current population dynamics of pathogens, which can be affected by human activities occurring in agro-ecosystems. Therefore, they should be described and evaluated on wild pathogen populations free of human-mediated disturbances. The aim of this work is twofold (1) assessing the evolutionary history of two cysts nematodes, Heterodera schachtii and Heterodera betae, and their common wild host, Beta vulgaris ssp. maritima, in wild populations sampled on the coast from the South of Spain to Sweden; (2) investigating at a fine spatial scale the population genetic structure of H. schachtii .Results show that the colonization of the Atlantic coastline by the two nematodes was probably influenced by climatic fluctuations occurring since the Last Glacial Maximum, along with marine currents. Phylogeographical patterns of H. schachtii and the host-plant suggest a non-shared evolutionary history, which contrasts with the coastal recolonization of Europe observed in H. betae. The fine-scale study evidenced that wild populations of H. schachtii are genetically sub-structured at the level of the host plant, strongly isolated and characterized by small effective population sizes. All these results are discussed in the framework of the sustainable management of nematodes populations in cultivated fields.
72

Pharmacochimie antiprotozoaire en séries quinazoline et quinoléine : synthèse, évaluation biologique et recherchedu mécanisme d'action. / ANTIPROZOAL PHARMACOCHEMISTRY IN QUINAZOLINE AND QUINOLINE SERIES : SYNTHESIS, BIOLOGICAL EVALUATION AND RESEARCH FOR THE MECHANISM OF ACTION

Kieffer, Charline 11 December 2014 (has links)
Le paludisme et la leishmaniose sont les deux plus importantes infections parasitaires au monde, en termes de mortalité. La recherche de nouvelles molécules actives contre les protozoaires responsables de ces « maladies tropicales négligées », Plasmodium sp et Leishmania sp, est un enjeu majeur de santé publique. Après une première partie dressant un état des lieux des connaissances disponibles en matière de chimiothérapie antiplasmodiale, une seconde partie s’est intéressée à l’étude des propriétés anti-infectieuses du noyau 2-trichlorométhyl-quinazoline, en introduisant en position 4 des motifs alcynyles par couplage de Sonogashira, optimisés par LC/MS. Une troisième partie a porté sur la pharmacomodulation en positions 2 et 4 du même noyau, notamment par réactions de SNAr. Une quatrième partie a consisté à rechercher le mécanisme d'action des meilleures quinazolines antiplasmodiales, via une approche de chromatographie d'affinité sur inhibiteur immobilisé. La fonctionnalisation multi-étapes des molécules les plus puissantes, par un bras espaceur, a été suivie de leur ancrage sur divers supports solides, pour constituer des matrices biocompatibles spécifiques. L’une d’entre-elles a permis la mise en évidence de 2 cibles plasmodiales protéiques originales : la GTPase Pfrab6 et la pyruvate-kinase PfpyrK1. Enfin, une cinquième partie relate la pharmacomodulation antileishmanienne du noyau 8-nitroquinoléin-2(1H)-one. Les travaux se sont intéressés à l'étude de la substitution de la position 4 de ce noyau par des réactions de SNAr, ainsi que des réactions de couplages pallado-catalysés optimisées à l’aide de la technologie micro-ondes. / Malaria and leishmaniasis are the two most important parasitic infections worldwide, in terms of mortality. Thus, the research for new molecules targeting the protozoa parasites responsible for these “neglected tropical diseases”, Plasmodium sp and Leishmania sp, constitute a major challenge in public health. Our work focused first on a current state of knowledge about antiplasmodial chemotherapy. In a view to develop the study of the anti-infective properties of the 2-trichloromethylquinazoline scaffold, a second part presented antiplasmodial pharmacomodulation at position 4 using Sonogashira cross-coupling reaction, optimized with the LC/MS technology. A third part concerned other pharmacomodulation reactions, especially at positions 2 and 4, using especially SNAR reactions. A fourth part consisted in the research of the mechanism of action of the best antiplasmodial quinazolines by using the affinity chromatography on immobilized inhibitor approach. The multi-step functionalization of the most potent derivatives by a spacer side chain was followed by their anchoring onto various solid supports, so as to generate different biocompatible specific matrices. One of them, put in contact with a parasitic lysate, allowed the identification of two original plasmodial targets: the GTPase Pfrab6 and the pyruvate-kinase PfpyrK1. Finally, a fifth part presented the antileishmanial pharmacomodulation of the 8-nitroquinolin-2(1H)-one scaffold, especially at position 4 of the quinoline ring, involving SNAr reactions (with amines, phenols or thiophenols) or pallado-catalyzed coupling reactions (in particular Suzuki-Miyaura), some of them being optimized under microwave irradiation.
73

Metabolismo de poliaminas durante a embriogênese somática de cana-de-açúcar. / Polyamines metabolism during somatic embryogenesis in sugarcane.

Amanda Ferreira Macedo 12 May 2010 (has links)
O estudo do metabolismo de poliaminas (PAS), envolvendo parâmetros fisiológicos, bioquímicos e moleculares, pode gerar uma melhor compreensão do processo de maturação, e criar estratégias importantes para a otimização da embriogênese somática (ES) em cana-de-açúcar. O objetivo deste trabalho foi estudar a relação entre os conteúdos endógenos de PAs, associados à determinação da competência embriogenética e a maturação progressiva de embriões somáticos em cana-de-açúcar. Calos embriogênicos (E) e não-embriogênicos (NE) da variedade SP-803280, foram submetidos a diferentes tratamentos, utilizando agentes de maturação adicionados ao meio MS. Observou-se que as culturas NE não foram capazes de promover a diferenciação de embriões somáticos, devido principalmente, ao alto grau de oxidação das culturas. Os tratamentos suplementados com 0,75 e 1,5 g.L-1 de carvão ativado (CA), foram os que apresentaram as maiores freqüências de formação de embriões somáticos. A partir dos resultados obtidos, foi possível associar a ES em calos de cana-de-açúcar ao aumento do conteúdo endógeno de Spd (Espermidina) e Spm (Espermina), principalmente Spd, acompanhado por uma redução nos níveis de Put (Putrescina). / Somatic embryogenesis (SE) is a highly potential supplier of the material involved in the regeneration and genetic transformation of transgenic plants. The aim was to study correlations between endogenous PA contents, associated to defining embryogenetic competence and the progressive maturation of somatic embryos. Embryogenic (E) and non-embryogenic (NE) calli from the SP-803280 variety, were submitted to different maturation treatments. It was found that the NE cultures submitted to the two maturation experiments, were incapable of promoting somatic embryo differentiation, mainly due to browning. It was noted that in the first experiment, total PA endogenous content of the E callus was higher than in the NE, although, in the control, no significant differences between both callus types were encountered. We can associate the progression of sugarcane somatic embryogenesis to an increase in endogenous content of Spd e Spm, mainly Spd, accompanied for a reduction in Put levels. Thus, it was shown that somatic embryo maturation in sugarcane can be related with PA biosynthesis, thereby indicating the importance of their metabolism in the competence of sugarcane embryogenic cultures.
74

Identifikace bakterií mléčného kvašení v tvrdých sýrech s využitím amplifikačních metod / Identification of lactic acid bacteria in hard cheeses using amplification methods

Herzogová, Jitka January 2008 (has links)
Diploma thesis was focused on identification of lactic acid bacteria of species Lactococcus lactis and subspecies Lactococcus lactis ssp. lactis and Lactococcus lactis ssp. cremoris using species and subspecies specific polymerace chain reaction (PCR). PCR method was used for identification of bacteria of species Lactococcus lactis in 10 samples of hard cheeses. The method of sample preparation was evaluated for hard cheeses with the aim to receive sufficient amount of cells for the preparation of crude cell lysates. Whole DNA in quality suitable for PCR was separated using magnetic microspheres P(HEMA-co-GMA) in the presence of polyethylenglycol (PEG 6000) and sodium chloride. DNA isolated by phenol extraction was used as control of DNA isolation. PCR was used to the analysis of 7 strains of Lactococcus lactis from Collection of dairy microorganisms Laktofora (CCDM). Altogether 5 or 2 strains were identified into subspecies Lactococcus lactis ssp. lactis and Lactococcus lactis ssp. cremoris, respectively.
75

Optimisation et analyse des résesaux intelligents et des réseaux hétérogènes / Optimization and analyze of intelligent networks and heterogeneous networks

Jabban, Ahmad 16 September 2013 (has links)
Le travail réalisé dans le cadre de cette thèse permet d’évaluer et d’optimiser la charge de signalisation dans les réseaux intelligents (RI) à grande échelle ainsi que d’analyser plusieurs aspects liés aux réseaux hétérogènes.L’objectif principal des RI est de faciliter l’introduction de nouveaux services en se basant sur plus de flexibilité et de nouvelles fonctionnalités. Les composants principaux d’un RI sont le point de commutation de services (SSP) et le point de commande de services (SCP). L’emplacement des équipements de réseau et la répartition du trafic peuvent jouer un rôle important dans la réduction du volume de la signalisation. Dans la première partie de la thèse, nous examinons plusieurs configurations du RI à grande échelledans le but d’analyser les effets du déplacement, de l’addition des nouveaux commutateurs SSP et de la redistribution du trafic au sein du réseau sur le nombre requis de liens de signalisation. Nous proposons un algorithme assurant la distribution optimale du trafic sur les commutateurs SSP avecle nombre minimum requis de liens de signalisation. Dans la deuxième partie de la thèse, nous analysons les différentes stratégies de sélection de réseaux dans un contexte de réseaux hétérogènes. En effet, dans la prochaine génération de réseaux sans fil et mobiles, les utilisateurs pourront se déplacer entre les réseaux hétérogènes en utilisant des terminaux équipés d’interfaces d’accès de plusieurs types. Dans ce contexte, les terminaux mobiles sont en mesure de choisir le lien d’accès le plus approprié parmi lesoptions disponibles. Dans notre travail, nous proposons une stratégie de sélection basée sur la valeur estimée de SINR (Rapport signal à interférence plus bruit) dans un système hétérogène composé de deux types de réseau : LTE et WiFi. Avec cette stratégie, les utilisateurs sélectionnent toujours leréseau présentant le SINR le plus élevé afin d’effectuer leurs communications. En se basant sur la méthode de Markov, nous analysons dans un premier temps, les performances de la stratégie de sélection basée sur le SINR en termes de probabilités de blocage de demandes d’accès aux services, de probabilités de blocage de handover vertical ou horizontal et de qualité de connexion. Nous comparons les résultats obtenus avec deux autres stratégies basées sur la puissance du signal reçu et sur la disponibilité de bande passante. Les performances sont analysées et comparées selon les modèles de mobilité 2D fluid flow et Random WayPoint qui sont largement utilisés dans l’analyse des réseaux sans fil et mobiles. Finalement, nous analysons les influences de l’allocation de ressources du réseau LTE aux services Multicast et Unicast sur les performances du système. / This thesis analyses the signaling load in intelligent large scale networks as well as the network selection strategies in the heterogeneous environment. The main objective of Intelligent Networks (IN) is to simplify the introduction of new services based on new features and more flexibility. The main components of the IN are the Service Switching Point (SSP) and the Service Control Point (SCP).The location of intelligent large-scale network equipments and the distribution of traffic on them can play an important role in reducing the volume of signaling in the network. In the firstpart of this thesis, we examine various configurations of the IN in order to study the effect of displacement or addition of new SSP and redistribution of traffic within the network on therequired number of signaling links. Finally, we propose a new algorithm giving the optimal distribution of traffic on the SSPs with a minimum required number of signaling links.In the second part of the thesis, we analyze the different network selection strategies as well as simulate other approaches related to heterogeneous wireless environment. Indeed, in the next generation of wireless heterogeneous networks, mobile users can move between several types ofnetworks, using terminals with multiple access interfaces. In this environment, the mobile terminals are able to choose the most appropriate access link among the available alternatives. In our work, we propose a network selection strategy based on the estimated SINR value (Signal to Interference-plus-NoiseRatio) in a heterogeneous system composed of two types of network: LTE and WiFi. According to this strategy, users always select the network presenting the highest SINR value. Based on the Markov method, we analyze the system performance in terms of blocking probabilities of calls, blocking probabilities of vertical or horizontal handover and connection quality. We compare our results with two other strategies based on the received signal strength and on the bandwidth availability.The performances are analyzed and compared according to the 2D fluid flow and the Random Waypoint mobility models which are widely used in the analysis of wireless and mobile networks. Finally, we analyze the influence of the resource blocks allocation to services Multicast and Unicast on the system performance.
76

Language for specific purposes (LSP) business Spanish textbooks: a content analysis

Marcé, Pilar 01 May 2019 (has links)
Since the 1990s, the number of courses of Spanish for Specific Purposes (SSP), especially Business Spanish, has increased rapidly in institutions of higher education in the U.S. Ideally, the design of these courses is based both on an analysis of the learners’ needs and on a specific business-related purpose. However, instructors of Business Spanish may not be specialists in this area and may lack the means or the time to perform a needs analysis (NA) to prepare the course syllabus and materials. Consequently, choosing the Business Spanish textbook ends up being the first step in designing the course, and for the reasons stated above, this choice tends to be based on the instructor’s needs rather than those of the learners. In this dissertation, I subjected four Business Spanish textbooks to an in-depth analysis (Littlejohn, 1998) in three stages. This analysis includes their approach to specificity (from narrow to wide), and how the business-related learners’ needs (language- and skill-based) are addressed. Results from these four analyses reveal that the authors adapted four different language teaching approaches and methods. Their wide-angled approach to specificity and different viewpoints of the target learners’ business-related needs are based on (1) their beliefs on the nature of language and language teaching, (2) the position of the course in the macro curriculum (macro-specific purpose), and (3) their respective target audiences. A two-step evaluation of Business Spanish textbooks is recommended to instructors based on the macro-specific purpose of their courses and the micro-specific purposes of communicative activities.
77

Safe Sleeping Position

Håkansson, Pontus, Knutsson, David January 2007 (has links)
<p>Project Safe Sleeping Position (SSP) contains all parts in a product development phase. The project comprises the whole cycle from idea to a complete product where all aspects are included. The scope is to develop an innovative solution for a common known problem and work with all parts within the man-machine-way. The result is an inflatable product which secures a child in the correct way for the seatbelt to work properly in the rearseat of a car. Ergonomics, technical extent, usability, design, construction, product solutions and market potential are some of all parts witch the project includes. The targetgroup for the project is children 4 to 12 years old, but there is a great potential for a further development to provide a solution for adults. </p><p>Signed project managers are commissioned by Volvo Car Corporation (VCC), a large car manufacturer with the whole world as the market. This sets requirements to the product to be adaptable to all markets without cutting down on usability. Except the assigner, the project comprises several partners, both companies, independent organizations and students at Halmstad University.</p>
78

Safe Sleeping Position

Håkansson, Pontus, Knutsson, David January 2007 (has links)
Project Safe Sleeping Position (SSP) contains all parts in a product development phase. The project comprises the whole cycle from idea to a complete product where all aspects are included. The scope is to develop an innovative solution for a common known problem and work with all parts within the man-machine-way. The result is an inflatable product which secures a child in the correct way for the seatbelt to work properly in the rearseat of a car. Ergonomics, technical extent, usability, design, construction, product solutions and market potential are some of all parts witch the project includes. The targetgroup for the project is children 4 to 12 years old, but there is a great potential for a further development to provide a solution for adults. Signed project managers are commissioned by Volvo Car Corporation (VCC), a large car manufacturer with the whole world as the market. This sets requirements to the product to be adaptable to all markets without cutting down on usability. Except the assigner, the project comprises several partners, both companies, independent organizations and students at Halmstad University.
79

NORC vs. non-NORC evaluation of profiles and impact of naturally occurring retirement communities /

Coppinger, Erin C. January 2006 (has links)
Thesis (M.G.S.)--Miami University, Dept. of Sociology and Gerontology, 2006. / Title from first page of PDF document. Includes bibliographical references (p. 31-32).
80

Jämförelse mellan två nedkylningsmetoder av helblodsenheter för vidare framställning av trombocytkoncentrat avsedda för transfusion / Comparison between two cooling methods of whole blood units for further preparation of platelet concentrates intended for transfusion

Bäckström, Annie January 2018 (has links)
Trombocytopeni behandlas primärt med trombocyttransfusion. Trombocytkoncentraten kan erhållas genom poolning av lättcellskikt framställda ur helblodsenheter från flera blodgivare. Helblodsenheterna kyls vanligen ner på en CompoCool®-platta för att snabbt komma ner till rumstemperatur och kan då prepareras redan efter 2 h. Detta brukar vara logistiskt fördelaktigt och gynnar erytrocyterna som framställs ur samma helblodsenheter. Det går även att låta helblodsenheterna kylas ner i rumstemperatur vilket å andra sidan sägs ge ett högre trombocytutbyte då studier visat att trombocyter är känsliga för kyla. Syftet med examensarbetet var att framställa och jämföra kvaliteten på trombocytkoncentrat där helblodsenheten hade kylts ner på CompoCool®-platta respektive kylts ner i rumstemperatur. Hypotesen var att trombocytutbytet skulle bli högre vid nedkylning av helblodsenheten i rumstemperatur än vid nedkylning på CompoCool®-platta. Framställningen av trombocytkoncentraten gjordes genom poolning av 5 st lättcellskikt och en påse trombocytsuspensionsmedium efterföljt av centrifugering och separation i en automatisk blodkomponents separator. Kvalitén utvärderades med avseende på trombocytkoncentration, leukocytkoncentration, swirling samt bakterieodling. Samtliga resultat för kvalitetskontrollerna låg inom de rekommenderade gränsvärdena. Det beräknade t-testet för trombocytkoncentrationen var högre än det kritiska t-värdet vilket innebar att det var en signifikant skillnad mellan de olika nedkylningsmetoderna. Genom användning av de erhållna resultaten kunde hypotesen bekräftas och slutsatsen dras att trombocytutbytet är signifikant högre då helblodsenheten kyls ner i rumstemperatur jämfört med CompoCool®-platta.

Page generated in 0.0687 seconds