RACK1 (Receptor for activated protein C kinase 1) est une protéine ribosomale associée à de nombreuses voies de signalisation. RACK1 est nécessaire à la traduction sélective de virus contenant des sites d’entrée interne du ribosome (IRES). En outre, l’expression de RACK1 est nécessaire au cours du développement, suggérant que ce facteur participe à la traduction de certains ARNm cellulaires. Dans le but de mieux comprendre la fonction de RACK1 chez la drosophile, j’ai au cours de ma thèse caractérisé l’interactome de RACK1 et un IRES viral régulé par ce facteur. J’ai également essayé d’établir un lien entre signalisation cellulaire et traduction, et montré que la région du knob est importante pour la fonction de RACK1 au ribosome. Enfin, j’ai établi que RACK1 est nécessaire à la réponse à des stress abiotiques, et identifié les gènes cellulaires régulés par RACK1 dans ce contexte. J’ai en particulier découvert que RACK1 était un régulateur négatif de l’expression de plusieurs gènes de l’immunité innée. Mes résultats suggèrent que RACK1 joue un rôle pivot au sein du ribosome, régulant la traduction de façon positive ou négative selon l’ARNm et le contexte cellulaire. / RACK1 (Receptor for activated protein C kinase 1) is a ribosomal protein associated to many signaling pathways. RACK1 is required for the selective translation of viruses containing internal ribosome entry sites (IRES). In addition, expression of RACK1 is necessary during development, suggesting that it regulates the translation of cellular mRNAs. In order to better understand the function of RACK1 in Drosophila, I have participated in the characterization of the RACK1 interactome and of a RACK1-dependent viral IRES. I have also attempted to establish a connection between the function of RACK1 in signaling and in translation, and I have shown that the knob domain of RACK1 is important for IRES-dependent translation. Finally, I have established that RACK1 is required for the response to abiotic stresses, and I have identified cellular genes regulated by RACK1 in this context. In particular, I discovered that RACK1 is a negative regulator of several innate immunity genes. My results suggest that RACK1 plays a pivotal role within the ribosome, regulating translation positively or negatively in an mRNA- and possibly context-specific manner.

La fusion laser sélective d’un lit de poudres (Selective Laser Melting – SLM) connait un véritable essor depuis quelques années,notamment en ce qui concerne la production de pièces métalliques. La faible densité des alliages d’aluminium, conjuguée à l’optimisation de conception rendue possible grâce aux procédés de fabrication additive, assure un gain de masse des structures conséquent, ce qui intéresse fortement les industriels des domaines automobile et aéronautique. Cependant, les propriétés finales des pièces aluminium fabriquées par SLM dépendent des nombreux défauts sont générés lors de la fabrication (porosités, fissuration à chaud, état de surface, …). Cette thèse s’intéresse aux moyens de mieux maîtriser ces problèmes en explorant trois axes : Une identification et sélection des méthodes de caractérisations adaptées aux spécificités des matériaux métalliques élaborés par les procédés de fabrication additive « lit de poudre » a été mise en place. Par exemple, la comparaison de différentes méthodes de détermination de la densité relative de pièces nous a permis de montrer les avantages et inconvénients de chacune des techniques employées ; Une étude du moyen de fabrication SLM a mis en évidence l’influence de différents facteurs (flux de gaz, position des éprouvettes sur le plateau de construction, méthodes de dépôt de la poudre) sur les propriétés finales des pièces produites.Ces éléments ont un impact sur la densité des pièces, leurs propriétés de surface et leurs propriétés mécaniques. Nous avons ainsi constaté que la façon de positionner une pièce sur le plateau est une étape de la préparation d’une fabrication à ne pas négliger ; Les études paramétriques menées sur deux types d’alliages d’aluminium, AlSi7Mg0,6 et AM205, ont montré que la composition chimique de l’alliage d’aluminium employé influence de façon non négligeable le jeu de paramètres opératoires à appliquer pour fabriquer une pièce de manière optimale. La densité d’énergie volumique ψ, rapport de la puissance laser avec le produit de la vitesse de lasage, de la distance inter-cordons et de l’épaisseur de couche, est utilisée de façon classique pour l’optimisation des conditions opératoires en SLM. Nos études expérimentales à différentes échelles (1D et3D) ont permis de mettre en évidence les limites de ce critère. La combinaison de ces résultats à la simulation numérique du lasage d’un cordon de poudre a servi de base à la définition d’un premier modèle dont l’objectif sera à terme d’optimiser le choix des paramètres de fabrication. / Interest in selective laser melting (SLM) has been growing in recent years, particularly with regard to the production of metal parts.The low density of aluminum alloys, combined with the possible design optimization enabled by additive manufacturing processes,ensures a significant decrease in the mass of structures which is very interesting for manufacturers in the automotive and aerospaceindustries. However, it is difficult to control the final properties of aluminum parts manufactured by SLM because many defects, suchas porosity, hot cracking, and surface roughness, are generated during the process. To better understand how to optimize theperformance of SLM aluminium parts, several studies were conducted during this work: An identification and selection of characterization methods well-adapted to the specificities of metallic materials developedby powder bed additive manufacturing processes was established. For instance, the comparison of different methods ofdetermining the relative density of parts showed the advantages and disadvantages of each of the techniques; A study of the SLM machine highlighted the influence of various factors (gas flow, positions of specimens on the constructionplate, or methods of depositing the powder) on the final properties of the produced parts. These elements have an impacton the density of the parts, their surface properties, and their mechanical properties. We found that the positioning of a pieceon the tray is a critical step in the preparation of a build that is not to be neglected; Parametric studies carried out on two types of aluminum alloys—AlSi7Mg0,6 and AM205—have shown that the chemicalcomposition of the aluminum alloy used has a significant influence on the set of operating parameters required tomanufacture an acceptable aluminum alloy part. The energy density, ψ, which is the ratio of the laser power to the productof the lasing speed, the hatching distance, and the layer thickness, is conventionally used for the optimization of the operatingconditions in SLM. Our experimental studies performed at different scales (1D and 3D) have shown the limits of this criterion.The combination of these results with the numerical simulation of the lasing of a single powder bead served as a basis forthe definition of an initial model, the final objective of which will be to optimize the choice of manufacturing parameters.

The U.S. Selective Service System currently excludes women from the talent pool based upon the DoD's 1981 ban on women in direct combat. The DoD has removed the exclusion and has implemented a gender-neutral policy standard for assignments. However, there appears to be a misalignment of national security policy as it relates to gender fairness that impacts Reserve Officer Training Corps (ROTC) participants in particular. Using Durkheim's functionalism theory as the theoretical foundation, the purpose of this phenomenological study was to examine institutional differences in policies regarding justice and gender among ROTC participants who are between 18 and 26 years of age in a Middle Atlantic University. Data were acquired through 10 interviews with ROTC members. These data were inductively coded and then subjected to Moustakas and Van Kaam's thematic analysis procedure. Key results included evidence that current policy is misaligned with gender enfranchisement, effective social change requires inclusion of both genders in registration, and a standards-based approach to equality is important to both men and women. This group of future military leaders wants the repeal of male only registration and the inclusion of female citizens as an expression of full citizenship and increased social equity. Further research using this methodological framework in different geographical regions and among different generations could add depth to the current body of knowledge. The implications for positive social change with new Selective Service registration policy would change the process towards registering all young adult citizens in the event of a national emergency which would be the codification of fairness and value for all citizens in public policy.

Thesis (M.Inf.) --University of Limpopo, 2008 / The aim of the study is to investigate which of the information delivery systems (communication strategies) established at government level are used by rural clinics, and whether such information delivery systems are accessible to rural end-users. A literature review discussing and assessing the use of information delivery systems was conducted. The survey method and semi-structured interviews were used to collect data from all Clinics at Ga- Molepo. The study revealed that rural end-users cannot access HIV/AIDS information because clinics use information delivery systems which are not acceptable and accessible to them. Recommendations for further study on the subject under investigation are provided. The study assumes that with the identified barriers and recommendations at their disposal HIV/AIDS campaigners will be in a good position to identify, package and employ information delivery systems which are suitable for end-users.

The non-structural protein 15 (NSP15) locus in Lineage A β-coronaviruses has two important functions during replication. The encoded endoribonuclease is conserved among coronaviruses. The function of the nsp15 protein is still not fully understood, but recent evidence suggests it may be involved in both replication and inhibiting viral sensing of double stranded RNA. In Lineage A β-coronaviruses, the RNA locus contains an inserted packaging signal (P/S). The P/S is essential for selectively packaging viral genomic RNA. While the P/S is required for selective packaging, it is not required for nsp15 protein function or viral replication. Utilizing this region, I studied the interactions of nsp15 protein during infection. Additionally, I studied the effect of selective packaging on virulence. Coronaviruses encode 16 nonstructural proteins in two open reading frames. These proteins are responsible for forming the replication/ transcription complex (RTC) and creating an environment conducive to viral replication. The RTC is an intricate complex of viral and host proteins with a largely unknown composition. While almost all nsps studied to date localize to sites of replication, the interactions between these proteins are not fully understood. In Chapter II, I describe studies of the interactions and localization of Nsp15 by creating an in situ hemagglutinin epitope tag. I found that mouse hepatitis virus nsp15 could tolerate an in situ tag when placed into the P/S (MHVNsp15-HA). MHVNsp15-HA had wild-type like replication in vitro. Nsp15 was localized to sites of replication throughout infection, with no localization to sites of assembly. Finally, nsp15 interacted with the RNA dependent RNA polymerase and putative primase during infection. These data demonstrate that nsp15 is a member of the RTC. During coronavirus replication two species of viral RNA are present, genomic RNA (gRNA) and sub-genomic RNA (sgRNA). These RNAs are co-terminal on both their 5’ and 3’ ends, containing the leader sequence and 3’ UTR/ polyA respectively. Even with these similarities, coronaviruses are adept at selectively packaging gRNA over sgRNA. This selective packaging is determined by the P/S, a 95 base pair stem-loop structure in the nsp15 locus. This RNA motif is sufficient for packaging of nonviral RNAs and has been shown to interact with the M protein from MHV. Moreover, when this RNA motif is deleted from MHV, (MHVPS-) selective packaging is lost during infection as sgRNAs become a large percentage of packaged viral RNA. In chapter IV I determined the effect of selective packaging on pathogenicity in vivo. Immunocompetent mice infected with MHVPS- had significantly better outcomes compared to MHV wild-type (MHVWT) infected mice. Peak viral loads were decreased in MHVPS- compared to MHVWT. Strikingly I found MHVPS- infected bone marrow derived macrophages had significant increases in type-I interferons (IFNs) and pathogenesis of MHVPS- was restored in mice deficient in IFN signaling. These data indicate that the P/S of MHV is an uncharacterized MHV virulence factor, which acts by preventing an increased IFN response during infection. In MHV, the nsp15 locus is translated into a functional protein and contains functional cis acting RNA elements both of which play a role in MHV replication. This work provides understanding of nsp15 localization and interactions which educate our understanding of the function of this conserved endoribonuclease. Additionally, this work demonstrates a unique function for the P/S not previously described. This work informs future studies of nsp15 protein function and the function of selective packaging during coronavirus infection.

Hot flashes are one of the most bothersome symptoms experienced by women who have undergone breast cancer treatment-induced menopause. This vasomotor symptom has been hypothesized to be responsible for decreased sleep quality. This study further investigated the relationship between hot flashes and sleep quality in this population. The convenience sample consisted of 30 women being seen at an outpatient clinic in a comprehensive cancer center in southwest Florida. All participants were between the ages of 36-65, had a diagnosis of breast cancer and were currently taking a selective estrogen receptor modulator for at least six weeks. The participants completed the Hot Flash Diary, Hot Flash Questionnaire, Hot Flash Related Daily Interference Scale, Pittsburgh Sleep Quality Index and a demographic form. The mean sleep score of the sample was 9.33 (SD= 4.4). Global sleep scores above five are indicative of poor sleep quality, and global sleep scores of eight or more have been linked to cancer-related fatigue. Sleep was strongly correlated with hot flash distress (r = .754, p. = .000) and hot flash severity (r = .718, p. = .000) and moderately correlated with hot flash interference (r = .507, p. = .004) and hot flash frequency while asleep (r = .680, p. = .000). The small sample size was a study limitation. However, study results do support findings from previous studies. This study addresses a symptom management problem that may give nurses better understanding of the experiences of their patients. These findings also may assist patients in helping their providers to understand the frustration they are experiencing with regard to their decreased sleep quality.

Energy harvesting using rectennas for infrared radiation continues to be a challenge due to the lack of fast switching diodes capable of rectification at THz frequencies. Metal insulator metal diodes which may be used at 30 THz must show adequate nonlinearity for small signal rectification such as 30 mV. In a rectenna assembly, the voltage signal received as an output from a single nanoantenna can be as small as ~30µV. Thus, only a hybrid array of nanoantennas can be sufficient to provide a signal in the ~30mV range for the diode to be able to rectify around 30THz. A metal-insulator-metal diode with highly nonlinear I-V characteristics is required in order for such small signal rectification to be possible. Such diode fabrication was found to be faced with two major fabrication challenges. The first one being the lack of a precisely controlled deposition process to allow a pinhole free insulator deposition less than 3nm in thickness. Another major challenge is the deposition of a top metal contact on the underlying insulating thin film. As a part of this research study, most of the MIM diodes were fabricated using Langmuir Blodgett monolayers deposited on a thin Ni film that was sputter coated on a silicon wafer. UV induced polymerization of the Langmuir Blodgett thin film was used to allow intermolecular crosslinking. A metal top contact was sputtered onto the underlying Langmuir Blodgett film assembly. In addition to material characterization of all the individual films using IR, UV-VIS spectroscopy, electron microscopy and atomic force microscopy, the I-V characteristics, resistance, current density, rectification ratio and responsivity with respect to the bias voltage were also measured for the electrical characterization of these MIM diodes. Further improvement in the diode rectification ratio and responsivity was obtained with Langmuir Blodgett films grown by the use of horizontally oriented organic molecules, due to a smaller tunneling distance that could be achieved in this case. These long chain polymeric molecules exhibit a two-dimensional molecular assembly thereby reducing the tunneling distance between the metal electrodes on either side of the insulating layer. Rectification ratios as high as 450:1 at ±200mV were obtained for an MIM diode configuration of Ni-LB films of Arachidic Acid films-(Au/Pd). The bandwidth of the incident radiation that can be used by this rectenna assembly is limited to 9.5% of 30THz or ±1.5THz from the center frequency based on the antenna designs which were proposed for this research. This bandwidth constraint has led to research in the field of frequency selective emitters capable of providing a narrowband emission around 30THz. Several grating structures were fabricated in the form of Ni-Si periodic arrays, in a cleanroom environment using photolithography, sputtering and deep reactive ion etching. These frequency selective samples were characterized with the help of focusing optics, monochromators and HgCdTe detectors. The results obtained from the emission spectra were utilized to calibrate a simulation model with Computer Simulation Technology (CST) which uses numerous robust solving techniques, such as the finite element method, in order to obtain the optical parameters for the model. Thereafter, a thorough analysis of the different dimensional and material parameters was performed, to understand their dependence on the emissivity of the selective emitter. Further research on the frequency selectivity of the periodic nano-disk or nano-hole array led to the temperature dependence of the simulated spectra, because the material parameters, such as refractive index or drude model collision frequency, vary with temperature. Thus, the design of frequency selective absorbers/emitters was found to be significantly affected with temperature range of operation of these structures.

Internationally, the impacts of deer have been widely studied, but little work has been conducted in Australia. Sambar (Cervus unicolor Kerr) were introduced to Victoria in the 1860s from Sri Lanka, and have become established throughout eastern Victoria. This study is located in the Yarra Ranges National Park, 100 km north east of Melbourne. The park primarily consists of three protected water catchments that contribute approximately 50% to Melbourne’s water supply. This study was conducted from 2005 to 2008 in the Upper Yarra and O’Shannassy catchments. Large open areas covered by forbs and grasses periodically form adjacent to the water body of the Upper Yarra reservoir. Sambar are frequently observed at the largest of these areas known as The Flats. The impacts of sambar at this locality and in other areas of the catchments were investigated. / Faecal pellet transect surveys determined that sambar occupancy and density was greatest on open flats, lower on forest edges adjacent to open flats (< 250 m), and significantly less in other forested areas of the catchment. Observations of The Flats revealed that hinds were the main demographic class represented, with a mean group size of 39 individuals, and up to 70. This is the largest aggregation of sambar ever reported anywhere in the world, and equates to an approximate density of 200 km-2 at this site. / Selective exclosures effectively differentiated the offtake of forage by sambar from that of native herbivores. Sambar contributed to the majority of offtake at The Flats, and were able to obtain a substantial proportion of their daily food requirements from this source. A culling program began in the Yarra Ranges National Park in May 2008, to reduce the large numbers of deer in the park. The cull reduced the time spent by sambar on The Flats, as determined by faecal pellet accumulation plots, and significantly reduced faecal pellet load and forage offtake. / Sambar significantly decreased relative foliage cover of shiny nematolepis (Nematolepis wilsonii), a threatened understorey tree, through their antler rubbing activities. Thrashing of shiny nematolepis saplings also significantly decreased relative foliage cover, with sambar selecting saplings with a larger stem diameter from those available. Rubbed trees and thrashed saplings experienced damage to, on average, over half the stem circumference. / Selective exclosures allowed differentiation of sambar and native herbivore browsing on forest understoreys. Browsing by sambar in high densities prevented the vertical growth of plants in the understorey, with branches above 60 cm in height most commonly browsed. Plants in the understorey were more frequently and intensely browsed in areas of high sambar density. Three species were browsed to a significantly greater extent by sambar than native herbivores: hazel pomaderris (Pomaderris aspera), prickly tea-tree (Leptospermum continentale) and prickly bush-pea, (Pultenaea juniperina). Sambar significantly reduced plant biomass in forest understoreys where they occur in high densities. / The presence of large, open herb-rich areas drives the high local densities and associated impacts of sambar within the Yarra Ranges National Park. Future areas of research are identified and management recommendations are outlined. A sustained culling program appears to be the only practical option to reduce sambar density and impacts at this locality.

Les systèmes sensorimoteurs autonomes, placés dans des environnements dynamiques, doivent répondre continuellement à la question ultime: comment contrôler les commandes motrices à partir des entrées sensorielles? Répondre à cette question est un problème très complexe, principalement à cause de l'énorme quantité d'informations qui doit être traitée, tout en respectant plusieurs restrictions: contraintes de temps réel, espace mémoire restreint, et capacité de traitement des données limitée. Un autre défi majeur consiste à traiter l'information incomplète et imprécise, habituellement présente dans des environnements dynamiques. Cette thèse s'intéresse au problème posé par la commande des systèmes sensorimoteurs autonomes et propose un enchaînement d'hypothèses et de simplifications. Ces hypothèses et simplifications sont définies dans un cadre mathématique précis et strict appelé programmation bayésienne, une extension des réseaux bayésiens. L'enchaînement se présente en cinq paliers: utilisation d'états internes; les hypothèses de Markov de premier ordre, de stationnarité et les filtres bayésiens; exploitation de l'indépendance partielle entre les variables d'état; addition d'un mécanisme de choix de comportement;la focalisation de l'attention guidée par l'intention de comportement. La description de chaque étape est suivie de son analyse selon les exigences de mémoire, de complexité de calcul, et de difficulté de modélisation. Nous présentons également des discussions approfondies concernant d'une part la programmation des robots et d'autre part les systèmes cognitifs. Enfin, nous décrivons l'application de ce cadre de programmation à un robot mobile.

<p>One major focus of anxiety research in recent years has been the identification of cognitive factors that promote increased vulnerability to anxiety. Cognitive formulations propose that anxiety is characterised by an increased tendency to attend to negatively valenced emotional information, and that this bias may play a causal role in the development and maintenance of clinical anxiety. Evidence suggests that this anxiety-linked processing bias occurs even in conditions in which the stimuli are masked in order to prevent awareness of the content (i.e., <i>preattentive bias</i>). The present thesis focused principally on the preferential processing of threat-related information that occurs outside awareness. Two different outcome measures were used to index preferential preattentive processing of threat-related information in non-clinical populations: The emotional Stroop task was used to index <i>selective attention</i> to masked presentation of threatening word stimuli, whereas skin conductance responses were used to index <i>selective autonomic responses</i> to masked presentation of threatening pictorial stimuli. The empirical studies in the present thesis showed that elevated levels of trait anxiety promote preferential preattentive processing of negatively valenced information, whereas elevated levels of social desirability (interpreted as defensiveness) generally prevent preferential preattentive processing of negatively valenced information, especially among those at higher levels of trait anxiety, irrespective of outcome measure used. Moreover, previous research has demonstrated that a person’s most common emotional reaction when encountering a stressful event is causally influenced by that person’s habitual tendency to selectively encode the most threatening aspects of all available information. Thus, preattentive bias (as measured with the emotional Stroop task) was used to predict the emotional responses (as seen on self-reported emotional distress and autonomic reactivity) following exposure to a laboratory stressor. This study showed that preattentive bias to negative information had significant effects on both self-reported and physiological measures in response to a laboratory stressor, but in diametrically opposite directions. Specifically, whereas preattentive bias was positively associated with self-reported negative emotional response, it was negatively associated with a physiological indicator of emotional response. The results were discussed in terms of an inability to automatically inhibit the processing of threatening cues, which seems to be a vulnerability marker for anxiety. Whether this bias is ultimately sufficient for the development of clinical anxiety remains to be examined in future research. Additionally, more information is needed before it can be established that the emotional Stroop task can be viewed as a reliable diagnostic tool for determining an individual’s anxiety status.</p>