• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 24
  • 15
  • 9
  • 8
  • 7
  • 5
  • 3
  • 3
  • 3
  • 3
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 103
  • 14
  • 13
  • 12
  • 11
  • 9
  • 8
  • 7
  • 7
  • 7
  • 6
  • 5
  • 5
  • 5
  • 5
  • 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

Génomique des populations appliquée : détection de signatures de sélection au sein de populations expérimentales / Applied population genomics : detection of signatures of selection in experimental populations

Hubert, Jean-Noël 21 June 2018 (has links)
La génomique des populations rend possible la mise en évidence de traces de sélection dans le génome. Les travaux effectués considèrent en général une échelle de temps longue (~ 10³ générations). En comparaison, peu d’intérêt a été porté aux études expérimentales de court terme (~ 10 générations). De telles expériences sont pourtant susceptibles de nous renseigner sur la base génétique de caractères complexes. Nous proposons une méthode de vraisemblance basée sur un modèle de Wright-Fisher pour détecter la sélection à partir d’échantillons génétiques temporels acquis sur une période de dix générations. Nous montrons par simulation que notre méthode permet de différencier les signaux dus à la combinaison de la sélection et de la dérive génétique de ceux dus à la dérive seule. Nous montrons également par simulation qu’il est possible d’estimer le coefficient de sélection appliqué à un locus testé. De plus, nous illustrons l’intérêt de notre méthode pour la détection de marqueurs candidats à la sélection au travers de deux études génomiques sur données réelles, chez le diable de Tasmanie (Sarcophilus harrisii) et chez la truite arc-en-ciel (Oncorhynchus mykiss). Ces applications mettent en évidence des régions génomiques candidates pour des phénotypes complexes dans des contextes différents. Dans l’ensemble, nos résultats montrent qu’il est possible de détecter des gènes sujets à une sélection directionnelle intense à partir d’échantillons génétiques temporels, même si la sélection est de courte durée et si les populations examinées ont un faible effectif. / Population genomics makes it possible to detect traces of selection in the genome. Studies in this field have mainly focused on long time scale (~ 10³ generations). In comparison, short-term experimental studies (~ 10 generations) have attracted much less interest. Such experiments are, however, likely to inform us about the genetic basis of complex characters. We propose a likelihood method based on a Wright-Fisher model to detect selection from genetic temporal samples collected over ten generations. We show through simulation that our method can disentangle signals due to the combination of genetic drift and selection to those due to drift alone. We also show through simulation that it is possible to estimate the selection coefficient applied to a tested locus. In addition, we illustrate the interest of our method for the detection of candidate markers for selection through two genome scans performed on real data, in the Tasmanian devil (Sarcophilus harrisii) and in the rainbow trout (Oncorhynchus mykiss). These practical applications highlight candidate genomic regions for complex phenotypes in different contexts. Collectively, our results show the possibility of detecting genes submitted to strong directional selection from genetic time-series, even if selection is applied on a short time period and if the examined populations are small.
32

Advancements in forensic DNA-based identification

Dembinski, Gina M. January 2017 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Modern DNA profiling techniques have increased in sensitivity allowing for higher success in producing a DNA profile from limited evidence sources. However, this can lead to the amplification of more DNA profiles that do not get a hit on a suspect or DNA database and more mixture profiles. The work here aims to address or improve these consequences of current DNA profiling techniques. Based on allele-specific PCR and quantitative color measurements, a 24-SNP forensic phenotypic profile (FPP) assay was designed to simultaneously predict eye color, hair color, skin color, and ancestry, with the potential for age marker incorporation. Bayesian Networks (BNs) were built for model predictions based on a U.S sample population of 200 individuals. For discrete pigmentation traits using an ancestry influenced pigmentation prediction model, AUC values were greater than 0.65 for the eye, hair, and skin color categories considered. For ancestry using an all SNPs prediction model, AUC values were greater than 0.88 for the 5 continental ancestry categories considered. Quantitative pigmentation models were also built with prediction output as RGB values; the average amount of error was approximately 7% for eye color, 12% for hair color, and 8% for skin color. A novel sequencing method, methyl-RADseq, was developed to aid in the discovery of candidate age-informative CpG sites to incorporate into the FPP assay. There were 491 candidate CpG sites found that either increased or decreased with age in three forensically relevant xii fluids with greater than 70% correlation: blood, semen, and saliva. The effects of exogenous microbial DNA on human DNA profiles were analyzed by spiking human DNA with differing amounts of microbial DNA using the Promega PowerPlex® 16 HS kit. Although there were no significant effects to human DNA quantitation, two microbial species, B. subtilis and M. smegmatis, amplified an allelic artifact that mimics a true allele (‘5’) at the TPOX locus in all samples tested, interfering with the interpretation of the human profile. Lastly, the number of contributors of theoretically generated 2-, 3-, 4-, 5-, and 6-person mixtures were evaluated via allele counting with the Promega PowerPlex® Fusion 6C system, an amplification kit with the newly expanded core STR loci. Maximum allele count in the number of contributors for 2- and 3-person mixtures was correct in 99.99% of mixtures. It was less accurate in the 4-, 5-, and 6-person mixtures at approximately 90%, 57%, and 8%, respectively. This work provides guidance in addressing some of the limitations of current DNA technologies.
33

Rheological Study of Linear and Nonlinear Viscoelastic Behavior for Silica-Reinforced Polybutadiene and Polystyrene

Thompson, Thaddeus January 2005 (has links)
No description available.
34

Dynamics anc Control of an Electric Power Assist Steering System

Kandula, Prasanth Babu 01 September 2010 (has links)
No description available.
35

Structure and dynamics of the penguin synnomes : understanding seabird life history and response to climate change through population genomics / Structure et dynamique des synnomes des manchots, ou comment la génomique des populations éclaire l'histoire de vie des oiseaux marins et leur réponse aux changements climatiques

Cristofari, Robin 23 February 2016 (has links)
L’Océan austral est l’un des pivot des écosystèmes et du climat de notre planète, qui concentre plus de 20% de la productivité primaire marine mondiale. La complexité de ses réseaux trophiques et son inaccessibilité rendent plus encore qu’ailleurs nécessaire l’utilisation d’espèces bio-indicatrices. Plusieurs espèces de manchots (comme le Manchot Royal et le Manchot Empereur) sont ainsi l’objet de programmes de suivi à long terme. Dans cette étude, nous utilisons les données offertes par la génomique des populations (« RAD-sequencing » couvrant le génome de centaines d'individus issus couvrant la distribution de ces deux espèces) et les représentations numériques du climat de l’IPCC-CMIP5 pour calibrer dans le temps long les analyses démographique plus précises réalisées à l'échelle de quelques générations dans le cadre de suivis démographiques, et mieux comprendre la réponse des manchots au changement climatique. Au-delà de ses conséquences immédiates pour l’étude des Manchots en tant que sentinelles de l’Océan Austral, cette étude montre l’intérêt d’une plus forte intégration de la génomique des populations dans les études démographiques et comportementales. / The Southern Ocean plays a central role in the regulation of the Earth’s climate and ecosystems, and accounts for more than 20% of the world’s marine productivity. The complexity of its trohpic networks and its sheer inaccessibility make the use of bioindicator species more necessary there than anywhere else. Several penguin species (such as the King and the Emperor penguin) are therefore the focus of long-term monitoring programs.In this study, we use the information from population genomics (« RAD-sequencing » data covering the genome of hundreds of individuals from the two species’ full distribution) and from IPCC-CMIP5 numerical climate models to calibrate in the long time the more precise demographic analyses realised in the framework of field surveys, and understand penguin responses to cliamte change. Beyond its implications for the study of penguins as sentinels of the Southern Ocean, our work demonstrates the interest of a stronger integration of population genomics in demographic and behavioural investigation.
36

Pictogramas e seu uso nas instruções médicas: estudo comparativo entre repertótios para instruções de uso de medicamentos / Pictogramas e seu uso nas instruções médicas: estudo comparativo entre repertótios para instruções de uso de medicamentos

Matos, Ciro Roberto de 02 October 2009 (has links)
Pictogramas e seu uso nas instruções médicas: estudo comparativo entre repertórios para instruções de uso de medicamentos. Esta pesquisa tem por objetivo analisar dois repertórios de pictogramas que representam instruções relacionadas ao uso e manipulação de medicamentos. A intenção é entender o seu processo de significação, adotando um protocolo qualitativo baseado nas dimensões semióticas da comunicação sígnica - pragmática, semântica e sintática - de Charles W. Morris. Para atingir este propósito, o estudo inicialmente resgata informações sobre os campos a que pertencem os pictogramas e os medicamentos - comunicação visual e área médica. Ele parte da elaboração de um panorama histórico dos principais fatos e pessoas que contribuíram com a produção e disseminação do uso de pictogramas para identificar as diferenças em sua utilização. Finalmente, verifica as aplicações e contribuições da comunicação visual na área médica. / Pictograms and their use in medical instructions: a comparative study between pictogram sets conveying instructions on the usage of medicine. This research aims to analyze two pictogram sets which represent instructions concerning the use and manipulation of medicine. The purpose is to understand their signification process by adopting a qualitative protocol, which is based on the signal communication semiotic dimensions - pragmatic, semantic and syntactic - by Charles W. Morris. In order to reach this goal, the study begins by presenting information about the fields where pictograms and medicine belong - visual communication and medical area. Then, with the intent to identify the differences in the use of pictograms, it formulates a historical panorama, which includes the main facts and people that contributed for the production and dissemination of these graphical symbols. Finally, it examines visual communication applications and contributions to medical area.
37

Rad aus WPC (Wood Polymer Composite) zum Einsatz in der Fördertechnik / WPC-Wheel for the use in conveying engeneering

Eichhorn, Sven, Clauß, Brit, Harsch, Ann-Kathrin 20 November 2015 (has links) (PDF)
Es wird die Bauteilentwicklung für ein Rad aus WPC (Wood Polymer Composite) vorgestellt. Das Rad ist der Demonstrator für eine WPC-Radbauweise zur Anwendung in der Intralogistik. Das Rad hat eine Lastgrenze von 150kg. Es werden statisch-mechanische Untersuchungen zu verschiedenen Materialrezepturen und Radkonstruktionen vorgestellt. Ergänzend werden tribologische Versuche von ausgewählten Rädern dargestellt, um die Praxistauglichkeit des Demonstrators und der Bauweise abzuschätzen. / A component- and material development for a wheel made from WPC (Wood Polymer Composite) is presented. The wheel is the demonstrator for a WPC-wheel design for the use in the intralogistics. The wheel has a load limit of 150kg. Staticmechanical investigations of different material compositions and wheel designs are presented. Tribological investigations of selected wheels are shown, to give an estimation of the prototype’s usability and the effectiveness of the general wheel design.
38

Pictogramas e seu uso nas instruções médicas: estudo comparativo entre repertótios para instruções de uso de medicamentos / Pictogramas e seu uso nas instruções médicas: estudo comparativo entre repertótios para instruções de uso de medicamentos

Ciro Roberto de Matos 02 October 2009 (has links)
Pictogramas e seu uso nas instruções médicas: estudo comparativo entre repertórios para instruções de uso de medicamentos. Esta pesquisa tem por objetivo analisar dois repertórios de pictogramas que representam instruções relacionadas ao uso e manipulação de medicamentos. A intenção é entender o seu processo de significação, adotando um protocolo qualitativo baseado nas dimensões semióticas da comunicação sígnica - pragmática, semântica e sintática - de Charles W. Morris. Para atingir este propósito, o estudo inicialmente resgata informações sobre os campos a que pertencem os pictogramas e os medicamentos - comunicação visual e área médica. Ele parte da elaboração de um panorama histórico dos principais fatos e pessoas que contribuíram com a produção e disseminação do uso de pictogramas para identificar as diferenças em sua utilização. Finalmente, verifica as aplicações e contribuições da comunicação visual na área médica. / Pictograms and their use in medical instructions: a comparative study between pictogram sets conveying instructions on the usage of medicine. This research aims to analyze two pictogram sets which represent instructions concerning the use and manipulation of medicine. The purpose is to understand their signification process by adopting a qualitative protocol, which is based on the signal communication semiotic dimensions - pragmatic, semantic and syntactic - by Charles W. Morris. In order to reach this goal, the study begins by presenting information about the fields where pictograms and medicine belong - visual communication and medical area. Then, with the intent to identify the differences in the use of pictograms, it formulates a historical panorama, which includes the main facts and people that contributed for the production and dissemination of these graphical symbols. Finally, it examines visual communication applications and contributions to medical area.
39

Développement et utilisation de marqueurs RADseq pour l'étude de l'impact de Wolbachia sur l'évolution des génomes mitochondriaux chez les Arthropodes / Development and use of RADseq markers to study the impact of Wolbachia on the evolution of mitochondrial genomes in Arthropods

Cariou, Marie 08 July 2015 (has links)
La propagation de bactéries intracellulaires invasives peut entrainer celle des génomes mitochondriaux qui leur sont liés génétiquement au sein du cytoplasme. Cette sélection par autostop peut conduire à une réduction de la taille efficace (Ne) pour le génome mitochondrial. Elle peut également favoriser l'introgression d'une mitochondrie introduite dans une espèce suite à une hybridation. Le principal objectif de ma thèse est de quantifier ces différents effets, de manière globale, au moyen d'un large échantillonnage d'Arthropodes de Polynésie française. Les événements d'introgressions mitochondriales sont à l'origine de discordances entre les histoires évolutives des génomes mitochondriaux et nucléaires. Afin de rechercher de telles discordances, nous avons développé des marqueurs génomiques nucléaires de type RADseq, permettant de reconstruire l'histoire des populations étudiées. J'ai pu montrer au moyen de simulations que ce type de données pouvait être utilisé pour inférer des relations phylogénétiques entre espèces (Cariou et al. 2013). Des améliorations du protocole RADseq nous ont également permis de démontrer l'applicabilité de cette méthode à de nombreux spécimens au sein de librairies hautement multiplexées (Henri et al. 2015). A partir d'analyses in silico, j'ai par ailleurs évalué l'importance de différents biais liés à l'utilisation de marqueurs RADseq pour estimer les diversités génétiques et proposé une méthode permettant de corriger certains d'entre eux. A partir de ces développements, j'ai pu démontrer que sur 30 espèces de Diptères et de Lépidoptères testées à ce jour, la proximité génétique mitochondriale est systématiquement confirmée par les marqueurs nucléaires, rejetant ainsi l'hypothèse d'une introgression mitochondriale récente. Sur un plus large échantillon, nous avons en revanche mis en évidence une réduction significative du Ne mitochondrial dans les lignées infectées par Wolbachia, suffisante pour réduire le polymorphisme, mais insuffisante pour générer une réduction notable de l'efficacité de la sélection naturelle / The spread of endosymbiotic bacteria can drive that of the linked mitochondrial genomes within the cytoplasm. This hitchhiking selection can lead to a reduction of the effective population size of the mitochondrial genomes (Ne). 1t can also facilitate mitochondrial introgression, following the introduction of exogenous mitochondria in a species by hybridization. The main objective of my thesis is to quantify these different effects, on a global scale, using a large sample of Arthropods. Mitochondrial introgressions can lead to discrepancies between the evolutionary histories of mitochondrial and nuclear genomes. To investigate such patterns, we used RADseq genomic markers, that allow reconstructing population histories, and developed improvements for the library preparation and data analysis. Using in silico experiments, 1 showed that RADseq data is suitable for phylogenetic inferences (Cariou et al. 2013). Adjustments in the RADseq protocol also allowed us to demonstrate the applicability of this method for highly multiplexed libraries (Henri et al. 2015). The impact of various biases related the estimation of population genetic diversity using RADseq was also investigated in silico, which lead me to propose an ABC method to correct some of them. Following these developments, 1 showed on 30 species of Diptera and Lepidoptera that nuclear markers always confirmed the mitochondrial genetic relatedness, ruling out the hypothesis of recent mitochondrial introgressions. On a larger sample, we detected a reduction of the mitochondrial Ne in Wolbachia infected lineages. This reduction caused a significant decrease in the polymorphism of infected populations, but appeared insufficient to reduce the efficacy of natural selection
40

Rad aus WPC (Wood Polymer Composite) zum Einsatz in der Fördertechnik

Eichhorn, Sven, Clauß, Brit, Harsch, Ann-Kathrin 20 November 2015 (has links)
Es wird die Bauteilentwicklung für ein Rad aus WPC (Wood Polymer Composite) vorgestellt. Das Rad ist der Demonstrator für eine WPC-Radbauweise zur Anwendung in der Intralogistik. Das Rad hat eine Lastgrenze von 150kg. Es werden statisch-mechanische Untersuchungen zu verschiedenen Materialrezepturen und Radkonstruktionen vorgestellt. Ergänzend werden tribologische Versuche von ausgewählten Rädern dargestellt, um die Praxistauglichkeit des Demonstrators und der Bauweise abzuschätzen. / A component- and material development for a wheel made from WPC (Wood Polymer Composite) is presented. The wheel is the demonstrator for a WPC-wheel design for the use in the intralogistics. The wheel has a load limit of 150kg. Staticmechanical investigations of different material compositions and wheel designs are presented. Tribological investigations of selected wheels are shown, to give an estimation of the prototype’s usability and the effectiveness of the general wheel design.

Page generated in 0.0159 seconds