Together with the current antibiotic resistance crisis, bacterial persistence appears to play an increasingly important role in the frequent failure of antibiotic treatments. Persister cells are rare bacteria that transiently become drug tolerant, allowing them to survive lethal concentrations of bactericidal antibiotics. Upon antibiotic removal, persister cells are able to resume growth and give rise to a new bacterial population as sensitive to the antibiotic as the original population. Interest in persister cells seriously increased in the past few years as these phenotypic variants were shown to be involved in the recalcitrance of chronic infections, such as tuberculosis and pneumonia and in the well-known biofilm tolerance to antibiotics. Persistence has therefore been extensively studied throughout the last decade, which led to the discovery of large variety of different molecular mechanisms involved in persisters formation. However, the specific physiology of bacterial persisters remains elusive up to now, mainly because of the transient nature and the low frequencies of persister cells in growing bacterial cultures. This work aims to gain a better understanding of the physiology of Escherichia coli persisters by combining population analyses with single-cell observations.In the first part of this thesis, we developed an experimental method allowing for measuring persistence with increased reproducibility. The method was further refined, which allowed us to observe four distinct phases in the ofloxacin time-kill curve, suggesting the existence of a tolerance continuum at the population level at treatment time. Characterization of these four phases notably revealed that the growth rate and the intrinsic antibiotic susceptibility of the strain define the number of surviving cells at the onset of the persistence phase, while persister cells survival mainly relies on active stress responses (SOS and stringent responses in particular).We next investigated the molecular mechanisms underlying the well-known correlation between persistence and the growth rate. Interestingly, we showed that the growth rate determines the number of survival cells at the onset of the persistent phase, whereas it does not affect the death rate of persister cells during antibiotic treatment. Furthermore, slow growth was shown to influence survival to ofloxacin independently of the replication rate, thereby suggesting that target inactivation solely cannot explain this correlation. However, our preliminary data indicate that ppGpp induction upon ofloxacin exposure substantially increases in slow growing bacterial populations, supporting a model in which slow growth would allow bacteria to respond faster to the antibiotic treatment, thereby generating more persisters than fast growing bacterial populations.Finally, both population and single-cell analyses were performed to assess the influence of the SOS response on persistence to ofloxacin. Firstly, population analyses revealed that the SOS response is required for survival of both sensitive and persister cells, but only during recovery, after ofloxacin removal, presumably allowing cells to induce SOS-dependent DNA repair pathways, required to deal with the accumulated ofloxacin-induced DNA lesions. The SOS response therefore appears as a good target for anti-persisters strategies, as shown by the 100-fold decrease in persistence upon co-treatment of a bacterial population with an SOS-inhibitor and ofloxacin. Secondly, single-cell analyses revealed that persister cells sustain similar DNA damages than sensitive cells upon ofloxacin treatment and induce SulA- and SOS-independent filamentation upon antibiotic removal, probably reflecting the presence of remaining cleaved complexes, formed during ofloxacin exposure. Importantly, we showed filamentation to occur in persister cells upon ampicillin treatment as well, thereby suggesting these filaments to be part of a more general survival pathway, which molecular basis remains unknown. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

D.Cur. / The occupation of the SOS mother, which involves long-term care for orphaned and abandoned children under the SOS Children's Villages organisation, is unique and peculiar in many respects. She is expected to play a dual role of being a foster parent and a childcare professional, at the same time. The latter presents challenges of its own because the professional status is only recognised internally by the organisation. In one way or another, most of the children for which the SOS mother is responsible, have been exposed to some form of trauma. The problems of caring and parenting such children are well documented in the literature. These include learning and behaviour problems. For this reason, the mental health of the SOS mother, who is the focus of this study, should be of special interest to mental health practitioner. The motivation for this study arises out of a change that the organisation is trying to enforce in the work of the SOS mother. This change comes with the release of the new quality standards to guide village work. One of these standards, the SOS mother's autonomy, requires the SOS mother, like any mother in the community to take full responsibility for her SOS family, including the development of the children under her care. When she needs help, she seeks expert advice from village co-workers and from the community. In addition, the career of the SOS mother has to be developed so that she functions like a childcare professional and that her training is recognised by the government and other training institutions. This represents a big change from how most SOS villages have been operating. Up to this point, village co-workers made important decisions about the SOS family and the children while the SOS mother did the caring part. The change is expected to affect the interactions between SOS mothers and their co-workers and consequently, their mental health. For this reason, it was felt that there was a need to facilitate the implementation of the SOS mother's autonomy standard, which would also promote the mental health of the SOS mothers. The purpose of this research was, therefore, to develop and describe a model that would serve as a framework for the advanced psychiatric nurse practitioner to promote the mental health of SOS mothers by facilitating the implementation of the SOS mother's autonomy within SOS Children's Villages of Southern Africa Region 11. The research also focused on developing guidelines for the implementation of the model in practice.

Dans ces travaux de thèse, nous proposons un système de communication original permettant d’atteindre un haut débit et de répondre aux exigences de la qualité de service requise pour les communications courte portée dans le cadre du transport intelligent. Ce système se base sur la technologie Ultra Large Bande Impulsionnelle (IR-ULB) et sur un nouveau schéma de modulation nommé M-OAM (M-Orthogonal Amplitude Modulation). Les modulations M-OAM se basent sur le principe des modulations M-QAM en remplaçant les porteuses par des formes d’ondes ULB orthogonales de type MGF (Modified Gegenbauer Function). Ces modulations ont été évaluées sous les conditions d’un canal AWGN et des canaux IEEE 802.15.3a et IEEE 802.15.4a qui tiennent compte des paramètres réels de la route. En plus du haut débit exigé par les communications inter-véhiculaires, il faut assurer un échange d’informations simultané entre plusieurs utilisateurs de la route et garantir une bonne qualité de service. Dans cette optique, une nouvelle technique d’accès multiple adaptée est proposée. Chaque utilisateur a la possibilité d’utiliser la modulation OAM adéquate selon le débit désiré. Le récepteur de ce système se caractérise par un aspect intelligent grâce à l’intégration des principes de la Radio Cognitive (RC) qui permet de détecter l’arrivée du signal et d’identifier les paramètres de la modulation utilisée afin de s’y adapter d’une façon autonome. Une bonne qualité de service est assurée par la proposition d’une nouvelle technique de démodulation qui se base sur les Statistiques d’Ordres Supérieurs (SOS) permettant d’éliminer le bruit Gaussien. Les bonnes performances du système de communication M-OAM ainsi que l’ensemble des aspects proposés ont été validés expérimentalement au sein du laboratoire IEMN-DOAE. Dans la dernière partie de ce document nous avons présenté la réalisation d’un prototype de ce traitement en temps réel sur une plateforme FPGA, en exploitant des algorithmes parallélisables sur des architectures reconfigurables. / In this work of thesis, we propose an original communication system allowing to reach high data rate and to fulfill the requirements of quality of service necessary for the communications short range dedicated to intelligent transport. This system is based on the Ultra Wide Band Impulse (IR-ULB) technology and on new modulation scheme named M-OAM (M-states Orthogonal Amplitude Modulation). M-OAM modulations are based on the principle of modulations M-QAM by replacingthe carriers used for QAM modulation with orthogonal waveforms ULB type MGF (Modified Gegenbauer Function). These modulations were evaluated under the conditions of AWGN channel and IEEE 802.15 channels which take account of the real parameters of the road. Besides the high speed required by inter-vehicular communications, it is necessary to ensure simultaneous information exchange between several users of the road. Accordingly, new adaptive multiple access system is proposed. Each user has the possibility to use the adequate modulation OAM according to the desired speed. The receiver of this system is characterized by an intelligent aspect thanks to the integration of the principle of Cognitive Radio (RC) which makes it able to detect the signal arrival and to identify the parameters of the used modulation in order to adapt the demodulation in an autonomous way. A good quality of service is ensured by the proposed novel demodulation method based on the Higher Orders Statistics (HOS) to eliminate the Gaussian noise. The good performances of M-OAM communication system M-OAM as well as the whole of the suggested aspects are validated in experiments within IEMN-DOAE laboratory. In the last part of this document we presented the realization of prototype using real time processing developed on FPGA plateform and exploiting parallelisable algorithms on reconfigurable architectures.

No description available.

After the democratic election of 1994, a new and integrated education system was developed in South Africa in accordance with international trends and the stipulations of the South African Bill of Rights with regard to equality, human dignity, basic education and equal access to education. According to the inclusive education system, learners with learning and developmental barriers should be accommodated within the mainstream of education. In order for inclusive education to succeed, a network of support was developed on departmental, provincial, district and school level. At school level, the school-based support team is directly responsible for supporting learners with learning and developmental barriers, educators and parents/caregivers. The effectiveness of these school-based support teams will, eventually, determine the quality of this inclusive education approach. The question which guided this research, is: How effectively does the school-based support team fullfil its function in the teaching and learning of learners with learning and developmental barriers within the framework of inclusive education? A qualitative research design was chosen which is exploratory, descriptive and explanatory. After an initial literature study in which international and national trends in this field were investigated, five primary mainstream schools were selected in the Western Cape according to certain criteria. A pilot study was conducted in another school to refine data collection strategies. Information was then gathered in the five schools by means of structured questionnaires, individual and focus group interviews, field notes and the study of appropriate documents. In order to evaluate these teams, eleven criteria were designed to serve collectively as an evaluation instrument. The effectiveness of the school-based support teams in the five schools were subsequently assessed and placed in various categories according to a conceptual framework. It was found that the school-based support teams function relatively effectively in most areas. The composition of the teams is effective. However, the teams function ineffectively with regard to the orientation and training of their members, as well as of the teachers and parents/caregivers of learners with learning and developmental barriers / Thesis (PhD (Educational Psychology))--University of Pretoria, 2008. / Educational Psychology / unrestricted

This thesis proposes an Ecosystem perspective for the engineering of SoS and CPS and illustrates the impact of this perspective in three areas of contribution category First, from a conceptual and Systems Engineering perspective, a conceptual framework including the Ecosystems of System Unified Language Modeling (EoS-UML) profile, a set of Ecosystem Ensemble Diagrams, the Arms :Length Trust Model and the Cyber Physical Threat Model are provided. Second, having established this conceptual view of the ecosystem, we recognize unique role of the cryptographic credentials within it, towards enabling the ecosystem long-term value proposition and acting as a value transfer agent, implementing careful balance of properties meet stakeholder needs. Third, we propose that the ecosystem computers can be used as a distributed compute engine to run Collaborative Algorithms. To demonstrate, we define access control scheme, risk-balanced Cellular Access Control (rbCAC). The rbCAC algorithm defines access control within a cyber-physical environment in a manner which balances cost, risk, and net utility in a multi-authority setting. rbCAC is demonstrated it in an Air Travel and Border Services scenario. Other domains are also discussed included air traffic control threat prevention from drone identity attacks in protected airspaces. These contributions offer significant material for future development, ongoing credential and ecosystem design, including dynamic perimeters and continuous-time sampling, intelligent and self optimizing ecosystems, runtime collaborative platform design contracts and constraints, and analysis of APT attacks to SCADA systems using ecosystem approaches.

This study investigated and evaluated the success and impact of the foodstuff package intervention that is offered by SOS Children’s Villages to households affected by HIV and AIDS. The study population comprised households who were involved in the food parcel distribution intervention, those affected by HIV and AIDS, those individuals who were able to talk freely about their lives as full participants and recipients of food parcels, and those aged 18 years and older. This study determined how food parcel intervention promotes self-sufficiency post-intervention. This was determined by interviewing recipients of food parcels from 2010 to 2018. The food parcel dissemination has been a core intervention to families affected by HIV and AIDS, but yielded very little progress towards assisting people to reach self-reliance. The aim of the study was to gain an understanding of the food parcel intervention using a qualitative research design. This study focused only on families affected by HIV and AIDS, including young people aged eighteen years and above. The study was based on a purposive sampling method with in-depth and focus group interviews as a means of collecting data. The results and implications of this study are discussed in depth in this research report. Essentially, the findings of this study could inform the development of policies and strategies to be considered for possible implementation by NGO’s and government in supporting family units affected by HIV and AIDS. / Sociology / M.A. (Social and Behavioural Studies in HIV and AIDS)

This paper deals with forms of compensatory care of unprovided children, taking in consideration their specific needs from the architecture-type point of view. The target group is that of big foster families, evaluation of their life requirements and defining their requirements of the living space, preparing the ground for legislative introduction of professional foster care.

Mathematics Education / M. Ed. (Mathematics Education)