Köln, Universiẗat, Diss., 2003.

Les carbapénèmes constituent le traitement de dernier recours des infections associées à des germes multirésistants producteurs de -lactamases à spectre étendu. Les entérobactéries ont cependant développé des mécanismes de résistance à l’encontre de cette classe d’antibiotiques, notamment par la production de carbapénèmases. La carbapénèmase OXA-48 a rapidement disséminé en Europe et dans le pays du pourtour méditerranéen depuis 2010. Les objectifs de ce travail ont englobé, dans une première partie, la caractérisation de trois variants de la carbapénèmase OXA-48, possédant chacun des particularités phénotypiques ou génétiques. Nous nous sommes ensuite intéressés à l’épidémiologie de la carbapénèmase OXA-48 afin de comprendre ses mécanismes de dissémination puis à la variabilité de son environnement génétique. Le dernier objectif était de déterminer les facteurs génétiques à l’origine de la dissémination de la carbapénèmase OXA-48. Nous avons ainsi montré que les carbapénèmases de type OXA-48 bénéficient de tous les éléments moléculaires pour assurer leur succès : mobilisation par un transposon actif pour certains variants, transfert efficace de plasmides et dissémination clonale de souches. / Carbapenems are often the last therapeutic option for treating infections involving multiresistant ESBL-producing bacteria. Nevertheless, enterobacteria have developped resistance mechanisms toward this class of antibiotics, including carbapenemases production. Carbapenemase OXA-48 has rapidly spread throughout Europe and various countries of Mediterranean area since 2010. The aim of this work was first to characterize three variants of the carbapenemase OXA-48, each possessing phenotypic or genetic characteristics. We focused on the epidemiology of carbapenemase OXA-48 in order to understand the mechanisms of its dissemination and on the variability of its genetic environment. The last objective was to determine the genetic factors responsible for the spread of carbapenemase OXA-48. We have shown that the OXA-48-type carbapenemases possess all the molecular elements to ensure its success: mobilization by an active transposon for some variants, efficient transfer of plasmids and clonal spread of strains.

This paper surveys and interprets the attitudes of scientists to the use of flux adjustments in climate projections with coupled Atmosphere Ocean General Circulation Models. The survey is based largely on the responses of 19 climate modellers to several questions and a discussion document circulated in 1995. We interpret the responses in terms of the following factors: the implicit assumptions which scientists hold about how the environmental policy process deals with scientific uncertainty over human-related global warming; the different scientific styles that exist in climate research; and the influence of organisations, institutions, and policy upon research agendas. We find evidence that scientists' perceptions of the policy process do play a role in shaping their scientific practices. In particular, many of our respondents expressed a preference for keeping discussion of the issue of flux adjustments within the climate modeling community, apparently fearing that climate contrarians would exploit the issue in the public domain. While this may be true, we point to the risk that such an approach may backfire. We also identify assumptions and cultural commitments lying at a deeper level which play at least as important a role as perceptions of the policy process in shaping scientific practices. This leads us to identify two groups of scientists, 'pragmatists' and 'purists,' who have different implicit standards for model adequacy, and correspondingly are or are not willing to use flux adjustments. / Includes bibliographical references. / Abstract in HTML and technical report in HTML and PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/) / Funded by the UK's Economic and Social Research Council as part of the "Science, Culture and the Enviroment" program at Lancaster University, UK.

Abstract In this thesis, the fabrication and performance of the OC-48 optical transceiver modules applied in optical communication network are studied. The optical transceiver modules consist of two parts¡Gthe transmitter and receiver. In the transmitter, laser driver IC and 1310nm FP (Fabry-Perot) Laser are used. In the receiver, limiting amplifier IC and 1310nm ROSA (Receiver Optical Sub-Assembly) are introduced. The static response of L-I curve and dynamic responses of VNA (Vector Network Analyzer) are studied. The effective bandwidth of LD can be observed from dynamic response. These parameters can help us to determine the LD driver for use in high frequency operation. Then, the method of DC-Coupling circuit to drive IC can be successfully transferred to optical signal. The operation conditions of an OC-48 transceiver module are the laser output power of -6dBm, signal pattern of 27-1, and data rate of 2.5Gb/s. The result of eye diagram measurement can meet the mask of ITU-T standards with the deterministic jitter of 49.88ps (0.1247 UI).¡CAfter 1 meter fiber transmission, the receiver can meet ITU-T standard with deterministic jitter of 125.28ps (0.3132 UI). In the future, the receiver should be improved to get a lower deterministic jitter.

No description available.

Abbie Griffin, John R. Hauser. / "October 1991; revised February 1992." / Includes bibliographical references (p. 43-50).

The Companies Act, 71 of 2008 repealed the Companies Act, of 61 of 1973, the former Act came into operation on the 1st May 2011.The repealing of the 1973 Act meant that a new legal dispensation was ushered in, these changes obviously affected the manner in which the law worked prior to the 1st May 2011. The repurchase of shares by the company is just but one of the many aspects which were affected by the new act. In order to understand the thought process of the legislature when enacting the current law, the history and evolution of section 48 is imperative. Section 80-90 and 46 together with 48 of the old and the new act respectively are the legislative framework behind the South African share repurchases rule. This research investigates the genesis of share repurchases in South Africa and thereafter observes the exodus from the original principle to the status quo. Prior to 1999, share repurchases were governed through the capital maintenance rule which was imported from England and other foreign jurisdictions. In terms of the capital maintenance rule the reduction of contributed share capital in any manner was prohibited. The issued share capital of the company was perceived as a guarantee fund intended for the payment of the claims of the creditors of the company in the event that the company defaults on its payments or is liquidated. In 1999, the Companies Amendment Act introduced sections 85 to 90 which was a paradigm shift from the out dated and superfluous share capital maintenance rule, this paradigm shift spared no sub rule within the capital maintenance rule and it is from these legal developments where we saw share repurchase rules including other sub-rules (which are beyond the scope this work) emerging. Section 48 of the new companies act read with other relevant sections the Act thereof prescribes the procedure and requirements for share repurchases, these sections further prescribe the consequences and remedies for non-compliance with the prescribed procedure and requirements. It is against this background that section 48 effects, impact as well as the interpretation thereof are investigated. In terms of section 48, the company may purchase shares issued by it under certain circumstances provided that it complies with the requirements laid down in the Act, furthermore section 48 transactions may under certain circumstances trigger tax liability for the parties involved. Copyright / Dissertation (LLM)--University of Pretoria, 2012. / Mercantile Law / unrestricted

No description available.

La mortalité cardiovasculaire représente la première cause de mortalité chez les sujets diabétiques de type 2. La dyslipidémie de ces patients caractérisée par le quatuor : hypertriglycéridémie, baisse du HDL-cholestérol, augmentation du nombre de LDL petites et denses et hyperlipidémie postprandiale, constitue un facteur de risque prépondérant. Cette dyslipidémie est en grande partie expliquée par l’accumulation sanguine des lipoparticules riches en triglycérides (TRL) d’origine hépatique (VLDL) et intestinale (chylomicrons). L’hyperproduction des chylomicrons, déjà connue pour les VLDL, est une composante nouvellement reconnue d’insulinorésistance. L’action inhibitrice aigüe de l’insuline sur la production des VLDL est absente chez le sujet diabétique de type 2. Dans notre étude, nous avons montré l’absence d’effet aigu de l’insuline sur la production des chylomicrons chez les sujets diabétiques de type 2 grâce à une étude cinétique utilisant un isotope stable (D3-leucine). / The cardiovascular mortality represents the first cause of mortality in human type 2 diabetes. The typical diabetic dyslipidemia characterized by the quartet: high triglyceride levels, low HDL-cholesterol, increased number of small and dense LDL particles and postprandial hyperlipidemia, is a major cardiovascular risk factor. This dyslipidemia is mainly explained by the accumulation of triglyceride-rich lipoproteins (TRL) from liver (VLDL) and intestine (chylomicrons).The overproduction of chylomicrons, as is known for VLDL, is a newly characteristic of insulin resistant states. The acute inhibitory effect of insulin on VLDL production is absent in type 2 diabetic patients. In our study, we have shown the absence of acute inhibitory effect of insulin on chylomicron production in type 2 diabetic patients, using a kinetic study with stable isotope (D3-leucine).

L'objectif de cette thèse était d'étudier l'influence de la texture poreuse et de l'acidité des catalyseurs d'hydrocraquage, sur l'activité et la sélectivité en distillats moyens. Dans notre étude, nous avons envisagé deux approches : d'une part la préparation des catalyseurs à partir de la zéolithe Y à texture poreuse optimisée, et d'autre part à partir d'une silice mésoporeuse de type MCM-48. Dans la première approche, l'optimisation de la texture poreuse a été réalisée par un traitement post synthèse de dessilication d'une zéolithe Y commerciale (CBV760). Les propriétés physico-chimiques des matériaux résultants ont été évaluées par différentes techniques de caractérisation. L'évaluation de ces matériaux en hydrocraquage de molécules modèles montre une très nette amélioration de la sélectivité en coupe moyenne par rapport à un catalyseur de référence à texture poreuse non optimisée. Dans la seconde approche, nos efforts ont été dirigés vers l'optimisation de l'acidité des solides de type MCM-48. Pour cela une méthode de greffage post-synthèse d'alumine à la surface de ce solide a été envisagée, conduisant à l'obtention d'une acidité suffisante pour la réaction d'hydrocraquage. L'évaluation catalytique de ces matériaux montre qu'ils sont des catalyseurs performants en hydrocraquage et en hydroisomérisation / The objective of this thesis was to prepare hydrocracking catalysts for heavy feedstocks with improved selectivity into middle distillates. In this study we followed two strategies: on the one hand the preparation of catalysts based on a zeolite Y with enhanced porosity, and on the other hand using a mesostructured silica (MCM-48). In the first approach, the optimization of the porous texture was realized by desilication of zeolite Y ( CBV760) in alkaline medium. Physico-chemical properties of obtained materials were investigated by various characterization techniques. The evaluation of these materials in the hydrocracking of model molecules shows a clear improvement of the selectivity into middle distillate with regards catalysts. In the second approach, our efforts were oriented towards the optimization of the acidity of MCM-48 type materials. To achieve this goal, an alumina layer was grafted on the surface of this material, generating an adequate acidity for the hydrocracking reaction. The catalytic evaluation of these materials shows a high selectivity inti middle distillates.