• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 673
  • 135
  • 93
  • 91
  • 44
  • 39
  • 25
  • 17
  • 16
  • 10
  • 7
  • 7
  • 5
  • 5
  • 4
  • Tagged with
  • 2471
  • 1290
  • 1211
  • 164
  • 149
  • 144
  • 142
  • 130
  • 128
  • 125
  • 107
  • 106
  • 105
  • 101
  • 101
  • 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.
1

L'infection à Coxiella Burnetii, de la clinique à la réponse de l'hôte

Melenotte, Cléa 23 November 2018 (has links)
La fièvre Q dans sa forme aiguë induit des pneumonies et des hépatites et plus rarement, dans sa forme persistante, des infections cardio-vasculaires. Sur la base des données du Centre National de Référence de la fièvre Q, de 1991 jusqu’à 2016, nous avons observé qu’à la phase aiguë, l’augmentation des anticorps anticardiolipines était associée à des complications cardiaques, neurologiques et des voies biliaires. Par ailleurs, nous avons décrit des cas de pneumopathies interstitielles associées et des cas d’endocardites aiguës. Nous avons montré l’existence d’une association entre l’infection persistante à C. burnetii, l’atteinte ganglionnaire et la survenue de cancer des ganglions, les lymphomes. L’étude comparative de la virulence de différentes souches de C. burnetii chez la souris a montré que la souche endémique et épidémique de Guyane Française était la plus virulente. / Q fever can be responsible of acute Q fever (pneumonia or hepatitis) and the infection could persist causing cardio-valvular infection. Based on the database of the national reference center for Q fever, from 1991 to 2016, we observed that the elevation of anticardiolipin antibodies was associated with acute Q fever cardiac, neurological and biliary tract complication. We described cases of interstitial lung diseases and report cases of acute Q fever endocarditis. We showed an association between persistent C. burnetii infection, lymph node involvement and lymphoma. The in silico, in vitro and in vivo comparison of 3 strains of C. burnetii have shown that the Guiana strain, which is endemic in French Guiana, was the most virulent strain.
2

Organisation, évolution et fonctionnement des gènes majeurs de domestication (Q/q) chez les blés polyploïdes / Organization, evolution and function of the major wheat domestication (Q/q) gene and its homoeologs in polyploid wheat

Belcram, Harry 16 June 2014 (has links)
En 2006, après un siècle d’investigations, le gène majeur de domestication 5AQ, conférant de nombreux caractères comme la non-déhiscence et un battage facile des épillets des blés polyploïdes, a été identifié comme un facteur de transcription homologue au gène Apetala2 d’Arabidopsis. Bien que ceci représente une avancée importante, le rôle des autres homéologues de ce gène, présents dans le blé tétraploïde (Triticum turgidum) et le blé hexaploïde (T. aestivum), reste à élucider. Dans ce contexte mon sujet de recherche porte sur l’appréciation de l’organisation, l’évolution et le fonctionnement du gène majeur de domestication (Q) et de ses homéologues chez les blés polyploïdes. J’ai tout d’abord séquencé et analysé 11 régions génomiques (clones BAC) portant les copies du gène Q/q dans différents génomes de blés polyploïdes et diploïdes; constituant ainsi la plus grande analyse comparative réalisée aujourd’hui chez le blé. Les comparaisons entre les différents génomes et différents niveaux de ploïdie montrent que le gène Q/q est la seule séquence conservée, en commun dans les régions génomiques comparées, et que l’homéologue 5Bq est pseudogénéisé dans les blés hexaploïdes. Les comparaisons montrent que le reste des séquences génomiques sont constituées d’environ 80% d’éléments transposables (TEs) qui sont entièrement différents quand on compare les génomes A, B, D et S entre eux. A l’inverse, les TEs sont relativement mieux conservés entre haplotypes du même génome et continuent leurs dynamiques d’insertions et de délétions différentielles, conduisant à 19 événements de rupture de synténie. Parmi ces événements, j’ai pu identifier le premier Hélitron actif du blé, inséré dans le pseudogène 5Bq du cultivar Renan. La recherche de son origine par comparaison de séquences et l’étude de la variabilité haplotypique m’ont permis de confirmer l’insertion récente et l’origine commune de cet élément au blé sauvage Aegilops ventricosa. Cette espèce a été introgressée dans certaines variétés de blés hexaploïdes. L’analyse fonctionnelle comparant les caractères de domestication ainsi que l’expression et les interactions entre les différents homéologues du gène Q/q dans le blé hexaploïde a été rendue possible par la caractérisation des « lignées de délétion », où une ou plusieurs copies homéologues ont été perdues ou substituées. J’ai pu ainsi caractériser l’hyper-fonctionalisation de l’homéologue 5AQ, et la sous-fonctionalisation des homéologues 5Dq et plus étonnamment 5Bq, pseudogénéisé ; les trois homéologues contribuent aux caractères de domestication et se régulent entre eux. Les comparaisons précises des séquences des allèles 5AQ et 5Aq pour plusieurs génotypes domestiqués et sauvages m’ont permis d’identifier une mutation SNP associée, dans le site d’adressage d’un micro RNA (miR172). L’utilisation d’une technique RACE-PCR semi-quantitative montre que la mutation dans l’allèle 5AQ conduit à moins d’ARNm clivés par les miR172 et donc à sa plus forte expression ; comparée à celle de l’allèle 5Aq. Ceci suggère un rôle des miR172 dans la régulation des différents homéologues du gène Q/q. / In 2006, and after a century of investigations, the major domestication gene in polyploid wheat (5AQ), involved in non free threshing and spike easy beating, among many other traits, has been identified as a homolog of Apetala2 gene of Arabidopsis. While this represents an important breakthrough, nothing was yet known about the role of other homoeologs of the Q/q gene present in tetraploid (Triticum turgidum) and hexaploid (T. aestivum) wheat. In this context, my PhD thesis consists in characterizing organization, evolution and function of the major wheat domestication (Q/q) gene and its homoeologs in polyploid wheat. I realized first comparative sequencing and analysis of 11 genomic regions (BAC clones) spanning the Q/q gene homolog’s in different hexaploid, tetraploid and diploid wheat; constituting the most important comparative analysis done for this group of species. Comparisons show that only Q/q gene homologs are conserved in different genomes and across different ploidy levels and that the 5Bq homoeolog is pseudogenized in hexaploid wheat. The remaining genomic sequences, constituted of ~80% of transposable elements (TEs) are completely different when comparing A, B, D and S genomes between each others. On the contrary, TEs are more conserved between different haplotypes of a same genome and continue their active insertion and deletion dynamic, leading to 19 identified synteny breaks. Among these, I identified the first active Hélitron in wheat inserted into the 5Bq pseudogene of a hexaploid wheat cv. Renan. The Hélitron insertion was subsequently retraced as recently occurring whereas it could have been originated from the wild wheat Aegilops ventricosa which has been introgressed into hexaploid wheat. Functional analysis comparing phenotype, domestication traits, expression and interaction between different Q/q homoeologs was rendered possible using series of “deletion lines”, where one or several homoeologs were deleted. This allows determining the hyper-functionalization of 5AQ and the subfunctionalization of 5Dq and more interestingly the subfunctionalization of the pseudogene 5Bq. All three homoeologs were shown to contribute to the domestication traits and regulate each others.Precise sequence comparison of 5AQ and 5Aq alleles from different domesticated and wild genotypes allow identification of a SNP mutation, associated with domestication, in the target site of a micro RNA (miR172). Using an adapted semi-quantitative RACE-PCR, I showed that the mutation leads to less cleaved mRNA of the 5AQ gene by the miR172 and consequently its higher expression than the 5Aq allele. This also suggests a general role of miR172 in regulating the different homoeologs of the Q/q gene.
3

Integrated filtering antennas for wireless communications

Mao, Chunxu January 2017 (has links)
In traditional radio frequency (RF) front-end subsystems, the passive components, such as antennas, filters, power dividers and duplexers, are separately designed and cascaded via the 50 Ω interfaces. This traditional approach results in a bulky and heavy RF front-end subsystem, and suffers from compromised efficiency due to the losses in the interconnections and the mismatching problems between different components. The frequency responses of the antennas such as the frequency selectivity and bandwidth are usually degraded, especially for microstrip antennas. To improve the frequency responses and reduce the size of RF front ends, it is important to investigate novel highly integrated antennas which exhibit multiple functions such as radiation, filtering, power dividing and combining or duplexing, simultaneously. In this thesis, several innovative designs of compact, multi-functional integrated an-tennas/arrays are proposed for wireless communication applications. First, new methods of designing integrated filtering antenna elements with broadband or dual-band performance are investigated. These antennas also feature high frequency selectivity and wideband harmonic suppression. Based on these studies, several integrated filtering array antennas with improved gains and frequency responses are developed for the first time. Compared with traditional array antennas, these proposed antennas exhibit improved bandwidths, out-of-band rejection and wideband harmonic suppression. The application of the filtering antennas in millimeter-wave (mm-Wave) frequency band is also investigated as it can potentially reduce the cost of the mm-Wave front-end subsystems significantly while providing the improved impedance bandwidth. The integrated design techniques are further developed to design novel dual-port highly integrated antennas with filtering and duplexing functions integrated. Such a new concept and the prototypes could find poten-tial applications in wireless communication systems and intelligent transportation system (ITS). In this thesis, comprehensive design methodologies and synthesis methods are provid-ed to guide the design of the integrated filtering antennas. The performance is evaluated with the help of full-wave electromagnetics (EM) simulations. All of the prototypes are fabricated and tested for validating the design concepts. Good agreement between the simulation and measurement results is achieved, demonstrating the integrated antennas have the advantages of compact size, flat gain performance, low losses and excellent harmonic suppression performance. These researches are important for modern wireless communication systems.
4

An investigation into various aspects of Q fever in Brisbane.

Powell, O. W. (Owen Watkins), 1921- Unknown Date (has links)
No abstract available
5

Serological response to Q fever antigens in natural inspection and after vaccination /

Worswick, David A. January 1989 (has links) (PDF)
Thesis (M. Sc.)--University of Adelaide, Dept. of Medical Virology, 1989. / Includes bibliographical references (leaves 211-237).
6

A strong Dixmier-Moeglin equivalence for quantum Schubert cells and an open problem for quantum Plücker coordinates

Nolan, Brendan January 2017 (has links)
In this thesis, the algebras of primary interest are the quantum Schubert cells and the quantum Grassmannians, both of which are known to satisfy a condition on primitive ideals known as the Dixmier-Moeglin equivalence. A stronger version of the Dixmier-Moeglin equivalence is introduced - a version which deals with all prime ideals of an algebra rather than just the primitive ideals. Quantum Schubert cells are shown to satisfy the strong Dixmier-Moeglin equivalence. Until now, given a torus-invariant prime ideal of the quantum Grassmannian, one could not decide which quantum Plücker coordinates it contains. Presented here is a graph-theoretic method for answering this question. This may be useful for providing a full description of the inclusions between the torus-invariant prime ideals of the quantum Grassmannian and may lead to a proof that quantum Grassmannians satisfy the strong Dixmier-Moeglin equivalence.
7

Topological solitons and their dynamics

Ashcroft, Jennifer January 2017 (has links)
Topological solitons are particle-like solutions of nonlinear field equations with important applications in physics. This thesis presents four research projects concerning topological solitons and their dynamics. We investigate solitons in (1+1)- and (2+1)-dimensions, and develop numerical methods to obtain static solutions and simulate soliton scattering. We first study kink collisions in a model with two scalar fields in the presence of false vacua. We find a variety of scattering outcomes depending on the initial velocity and vacuum structure. Kinks can either repel, form a true or false domain wall, annihilate, or collide and escape to infinity. These behaviours occur in alternating windows of initial velocity. When the kinks escape to infinity, there are a number of oscillations or 'bounces' before the kinks escape, and this bounce number is conserved in each of the windows. In the second project we design new baby Skyrme models that do not require a potential term to allow topological soliton solutions. We raise the Skyrme and sigma terms to fractional powers, which enables us to evade Derrick's theorem. We calculate topological energy bounds for our models and numerically obtain minimal energy solutions for solitons of charge 1, 2, and 3. For each charge, the minimal energy solution is a ring. The last two projects concern vortices in the Ginzburg-Landau model. In the first of these, we numerically investigate the scattering of multi-vortex rings. When two 2-vortex rings collide, there are two distinct scattering outcomes. In both cases, one pair of vortices will scatter at right angles and escape along the y-axis. The remaining two vortices will either form a bound state or escape along an axis after colliding a number of times. Finally, we study vortices scattering with magnetic impurities of the form σ(r)=ce-dr2 An impurity will attract or repel a vortex depending on the coupling constant λ and the parameters c and d. We scatter critically coupled vortices with two different impurities and explore the relationship between the scattering angle and impact parameter. We also find that a 2-vortex ring will break up in a head-on collision with an impurity.
8

Physiological and biomechanical analysis of prolonged and repeated bouts of load carriage

Scales, J. January 2017 (has links)
Previous work has attempted to define the physiological determinants of load carriage over a single day of load carriage, primary aims of this thesis were to determine the physiological and biomechanical changes as a result of load carriage and to explore the causes of these changes during load carriage and to explore these changes over multiple days of activity. A secondary aim was to explore individual differences in performance and possible mechanisms for this. Chapter 4 observed acute changes in vertical ground reaction force, supported by effect sizes which suggests individual differences in performances (loading peak dCohens=1.66 and dGlass 4.49). These findings were supported by no change in first negative rate which suggests increased knee flexion is occurring to mitigate the effect of the load. Differences in anteroposterior ground reaction force variables suggest that changes in gait may affect movement economy. Energy expenditure was shown to be correlated to a number of strength variables, such as ankle plantarflexion (r=-0.47) and knee extensors(r=-0.46). Similar variables were studied as a result of 2 hours treadmill load carriage in chapter 5. An additional variable was the study of torque at specific joint angles in addition to peak torque. Drift was observed for V̇O2 (68.93%). The torque curves showed significant reduction for load carriage, around the optimum muscle lengths for force (Knee extension at 180°s-1: 95°-125°, knee flexion at 180°s-1: 95°-125°) with findings supported by the peak torque values, suggesting there is no shift in muscle function. These findings were supported by associations between knee extension neuromuscular function scores, ankle plantarflexion neuromuscular function scores and energy cost variables which suggest that reductions in neuromuscular function may account for the increased energy cost. Chapter 6 observed load carriage on repeated days. The chapter observed that energy cost did not recover to baseline 24 hours post day one (4.41%). Further increases in energy cost and V̇O2 were observed post day two for energy expenditure and V̇O2 which suggest that a cumulative increase in energy cost as a result of load carriage occurred. Knee extension at 60°s-1 and 0°s-1 was shown to not recover 24 hours post day one, these variables were shown to show increased reduction for post day two and day three. Similar findings were observed within the ankle plantarflexors but no significant changes were observed for knee flexion and ankle dorsiflexion. Variables were also studied in a field setting during a >12hour load carriage task by Greek Special Forces soldiers. This study observed increased Medial and lateral deviations of the centre of pressure which suggests ankle instability even during unloaded walking as a result of load carriage. Large reductions were observed in vertical jump height and power as a result of the task, however this did not correlate to any biomechanical findings.
9

New diagnostic tools for capture-recapture models

Jeyam, Anita January 2017 (has links)
Capture-recapture models have increased in complexity over the last decades and goodness-of-fit assessment is crucial to ensure that considered models provide an adequate fit to the data. In this thesis, my primary emphasis is to develop new diagnostic tools for capture-recapture models in order to target possible reasons of lack-of-fit, which might provide biological insights and point towards better-fitting candidate models. Starting with the basic Cormack-Jolly-Seber model, I develop a new tool for detecting heterogeneity in capture. I then progress to the more complex multi-state models, for which I propose a test for detecting a mover-stayer structure within the population. Finally, I move on to more general models presenting additional levels of uncertainty: first partial observations and then unobservable states. In the presence of partial observations, part of the observations are assigned to states with certainty whereas others are not. I develop a new test for the underlying state-structure of the partial observations, this test detects that the partial observations are not generated by the observable states defined in the experiment. In the presence of unobservable states, the additional level of uncertainty relates only to the non-captures. I present a procedure to test whether one or two unobservable states need to be defined in order for the model to provide an adequate fit to the data. Lastly, I explore the use of multi-state models to incorporate individual time-varying covariates, based on a fine discretisation of the covariate space.
10

Definição da função Q-Gaussiana bidimensional com aplicações em processamento digital de imagens/

Gallão, Celso Denis January 2016 (has links)
Tese (Doutorado em Engenharia Elétrica) - Centro Universitário FEI, São Bernardo do Campo, 2016

Page generated in 0.0266 seconds