Nous avons étudié la synthèse, la structure et l'évolution sous gaz de nanoparticules (NPs) bimétalliques Au-Cu sur la surface (110) du rutile TiO2. Les NPs ont été obtenues par évaporation sous UHV. Pendant la croissance, la nature des sites de nucléation et l'évolution des densités et distributions de taille des NPs ont été suivies par microscopie à effet tunnel (STM), tandis que la structure et les relations d'épitaxies avec le substrat ont été suivies par diffraction de rayons X en incidence rasante (GIXD). Ces caractéristiques ont été mesurées sous oxygène, sous monoxyde de carbone ou sous mélange CO+O2 jusqu'à des pressions de 10-5 mbar.Nous montrons par STM que les défauts de la surface de type cluster de TiOx sont des sites de nucléation préférentiels pour les NPs. Par ailleurs, des NPs Au-Cu sont obtenues lors de l'évaporation séquentielle d'Au suivi de Cu. Les résultats de GIXD montrent que le Cu diffuse dans le volume des NPs d'Au initiales et forme une solution solide cfc. Les relations d'épitaxies entre les NPs alliées et le substrat indiquent que l'axe <110> des NPs est parallèle à l'axe [001] du substrat, mais que différentes orientations du plan interfacial sont possibles.En fonction de leur composition, la morphologie et à la structure des NPs sont modifiées sous faible pression d'oxygène. Tandis que les NPs de Cu pur disparaissent progressivement sous gaz, une faible proportion d'Au (de l'ordre de 5%) permet de les stabiliser. Cependant, les mesures de diffraction montrent que le Cu migre à la surface des NPs. Un recuit des NPs sous UHV permet de retrouver leur structure initiale. / We have studied the synthesis, the structure and the evolution in reactive environment of Au-Cu bimetallic nanoparticles (NPs) deposited under UHV on a (110) surface of rutile TiO2. During the growth, the type of the nucleation sites and the evolution of both density and size distribution of the NPs were followed with Scanning Tunneling Microscopy (STM), whereas the structure and the epitaxial relations with the substrate were determined using Grazing Incidence X-ray Diffraction (GIXD). These features were measured under oxygen, carbon monoxide and a mix of CO+O2 for pressures bellow 10-5 mbar.We show trough STM imaging that TiOx type of surface defects are a preferential nucleation site for NPs. Moreover GIXD results show that the Cu is able to diffuse inside the initial Au NPs to form a solid solution of fcc structure. The epitaxial relations between alloyed NPs and substrate indicate that the <110> axis of the NPs is parallel to the [001] axis of the substrate, but several orientations for the interfacial plan are possible.According to their composition, the structure and the morphology of the NPs can be modified in the presence of a low pressure of oxygen. Whereas Cu NPs progressively disappear in reactive environment, a small proportion of Au (around 5%) is enough to stabilize the morphology of the NPs. However, diffraction measurements show that in these conditions, the Cu segregates to the surface of the NP. A thermal annealing of the NPs under UHV allow to recover their initial structure.

Ovos e seus produtos derivados têm sido envolvidos em surtos de doenças transmitidas por alimentos devido à contaminação por Salmonella Enteritidis. A irradiação é uma das tecnologias existentes para a conservação de alimentos que poderia minimizar esse problema. O objetivo desta pesquisa foi determinar o efeito da irradiação sobre ovo líquido, ovo congelado, ovo em pó, gema em pó e clara em pó contaminados com Salmonella Enteritidis. As amostras de ovo líquido, clara em pó e gema em pó, inoculadas com S. Enteritidis, foram expostas a doses de 0,5; 1,0; 1,5; 2,0; 2,5; 3,0 kGy e as de ovo congelado e ovo em pó foram irradiadas com 0,5; 1,0; 1,5; 2,0; 2,5; 3,0; 3,5 e 4,0 kGy. Amostras não inoculadas e irradiadas e amostras não inoculadas e não irradiadas dos diferentes tipos de ovos foram testadas quanto ao odor cru, odor e sabor cozidos, cor, viscosidade e oxidação lipídica. Doses de 2,0; 3,0; 3,5; 3,0 e 3,5 kGy reduziram em 5 ciclos log a população de S. Enteritidis em ovo líquido, ovo congelado gema em pó, clara em pó e ovo em pó, respectivamente, com alterações levemente perceptíveis pelo painel de degustadores. A cor não sofreu alteração ou sofreu alteração moderada. As alterações mais intensas foram verificadas para viscosidade dos produtos em pó e para o aumento da concentração de malonaldeído em gema e ovo em pó. Portanto, o emprego da irradiação é factível para ovo líquido e congelado. Para os em pó, porém, deve ser ressaltado que a aplicação do processo está condicionada ao uso final do produto ao quais serão adicionados devido à alteração na viscosidade. / Eggs and their products have been incriminated in foodborne disease outbreaks due to Salmonella Enteritidis contamination. Irradiation is a food preservation technology that could be applied to minimize the problem. The aim of this study was to determine the effect of irradiation in liquid and frozen egg as well as in powdered egg, egg yolk and egg white spiked with Salmonella Enteritidis. Spiked samples of liquid egg, egg white and egg yolk were exposed to 0,5; 1,0; 1,5; 2,0; 2,5; 3,0 kGy and spiked samples of frozen and powdered egg were exposed to 0,5; 1,0; 1,5; 2,0; 2,5; 3,0; 3,5 e 4,0 kGy. Raw odour, cooked odour and taste of non inoculated and irradiated samples and non irradiated samples of egg and egg products were analysed by a trained panel. Viscosity and lipid oxidation (malonaldheyd concentration) were also determined. Doses of 2,0; 3,0; 3,5; 3,0 e 3,5 kGy reduced in 5 log the population of S. Enteritidis in liquid and frozen egg, powdered egg yolk, egg white and egg, respectively, with moderate alterations in relation to non irradiated samples detected by the trained panel. Viscosity and lipid oxidation in the powdered products, however, showed more intense alterations. Therefore, irradiation can be considered a feasible process for liquid and frozen egg while when applied to powdered products it should be considered the type of food product to which they will be added due to alterations in viscosity.

O Brasil é um dos principais exportadores de carne bovina. A maioria do gado é criada a pasto, porém uma parte já é confinada, como na criação de Novilhos Superprecoces. Este confinamento pode favorecer a contaminação por L. monocytogenes (Lm) do rebanho, bactéria responsável pela listeriose, doença que provoca aborto, neuropatias e gastrenterites. Com isto, pesquisou-se a presença e características sorotípicas e moleculares de Lm durante o confinamento de cinco raças de novilhos e em suas carcaças no frigorífico A, assim como amostras de carcaças, utensílios, equipamentos e ambiente em outro frigorífico (B). Foram utilizadas para tipar as cepas técnicas de sorotipagem por multiplex PCR, soroaglutinação e PFGE. Nenhuma Lm foi isolada nas 645 amostras do confinamento, sendo 13/48 carcaças dos novilhos, assim como amostras de piso e parede da câmara fria positivas para Lm no frigorífico A. Das 516 amostras do frigorífico B, 27 continham Lm, sendo a maioria proveniente da área limpa. Verificou-se que os sorotipos 1/2c e 4b foram os mais freqüentes no frigorífico A e o 1/2b e 1/2c no frigorífico B. A análise por PFGE forneceu 15 perfis Ascl, 13 Apal e 21 perfis compostos, caracterizando sete grupos clonais. Nesta cadeia produtiva de carne o principal ponto crítico para Lm está na área limpa do frigorífico e que cepas de mesmos grupos clonais puderam ser encontrados em ambos frigoríficos, assim como em áreas distintas do frigorífico B, demonstrando o alto poder de disseminação destas cepas. Portanto, estes resultados podem auxiliar no desenvolvimento de programas de boas práticas e HACCP para prevenir ou eliminar a contaminação por este patógeno. / Brazil is one of the most important beef producer/exporter country worldwide. The majority of the cattle is raised extensively, but some of them are feedloted. Confinement conditions can stress the animals and favor the contamination and proliferation for Listeria monocytogenes (Lm), agent of listeriosis which causes abortion, stillbirths, nervous dysfunctions and gastroenteritis. The aim of this study was to verify the presence of this microorganism and its molecular and serotype characteristics. Two groups of samples were analyzed: first, during the confinement of five different breeds of steers and on their carcasses (abattoir A). Second, at the slaughter and processing of other groups of beef cattle (abattoir B). The Lm strains were serotyped with commercial antisera and by multiplex PCR, and subtyped by PFGE. No Lm was found among the 645 samples of feces, environment, feed and water during the confinement, but 13/48 of the refrigerated carcasses were contaminated, as well as the floor and the wall of the cold room at the abattoir A. Amongst the 516 samples of slaughter and processing environments, carcasses, utensils and equipment collected from abattoir B, 27 harbored Lm, being the majority from the c1ean area. Serotype 1/2b and 4b were the most frequent Lm serotypes in the carcasses of the steers in abattoir 1, and 1/2b and 1/2c in the abattoir B. The molecular typing by PFGE resulted in 15 Ascl and 13 Apal profiles, and 21 composite profiles, resulting in seven clonal groups. In these beef production chains the most important critical point for Lm contamination is the c1ean area of meat processing. Same clonal groups could be isolated in both abattoirs and in different areas on abattoir B, demonstrating high dissemination capability of these strains. Therefore, these results could aid the development of good manufacturing practices and HACCP, to prevent or eliminate the contamination for this pathogen.

Objectives: The aim of the study was to evaluate how lower limbs injuries are related to footstrike pattern in 800 m women runners aged 16 - 22 in the Czech Republic and around the world. Methods: Due to the current epidemiological situation, the original field investigation of 48 runners was not possible to complete. Literature research on the topic and the series of ten case studies were performed instead. The research was performed in following databases: Medline, ScienceDirect, SPORTDiscus and Bibliographia medica Čechoslovaca. Results showed seven studies that met inclusion criteria. After that footstrike pattern was evaluated and compared with injury history in 10 women runners in 800 meters, who took part in the Czech Republic championship. Results: Two studies out of seven confirmed a higher incidence of injuries in RFS than in FFS, 4/7 did not show a significant difference, 1/7 did not evaluate the higher incidence in one or the other type of the footstrike. Three studies out of seven confirmed the relationship between RFS and knee injuries. Furthermore, two of them showed relationship between RFS and hip pain. 2/7 did not confirm any relationship between footstrike pattern and specific injury and 2/7 did not evaluated this relationship at all. Based on the series of ten case studies, it...

To ensure the highest possible temporal resolution of SAR data, it is necessary to use all the available acquisition orbits and paths of a selected area. This can be a challenge in a mountainous terrain, where the side-looking geometry of space-borne SAR satellites in combination with different slope and aspect angles of terrain can strongly affect the backscatter intensity. These errors/noises caused by terrain need to be eliminated. Although there have been methods described in the literature that address this problem, none of these methods is prepared for operable and easily accessible time series analysis in the mountainous areas. This study deals with a land cover-specific local incidence angle (LIA) correction method for time-series analysis of forests in mountainous areas. The methodology is based on the use of a linear relationship between backscatter and LIA, which is calculated for each image separately. Using the combination of CORINE and Hansen Global Forest databases, a wide range of different LIAs for a specific forest type can be generated for each individual image. The algorithm is prepared and tested in cloud-based platform Google Earth Engine (GEE) using Sentinel-1 open access data, SRTM digital elevation model, and CORINE and Hansen Global Forest databases. The method was tested...

In the first part of this thesis we generalise the well-known K-terminal reliability R(G,K) to different kinds of terminal vertices. By means of lattice theoretic tools, we propose a divide and conquer approach to compute this new reliability measure efficiently. The first part concludes with an improved path decomposition algorithm that computes R(G,K) much more memory and time efficient compared to current state-of-the-art algorithms. In the second part we discuss the counting of connected set partitions of a graph G and its application to network reliability problems. Again we utilise the lattice theoretic approach to carry out the counting efficiently. Finally, we investigate the domination reliability DR(G) of a graph G as an interesting network reliability measure.

Aim: To explore the role of cannabis use for the availability of ecstasy as a potential pathway to subsequent first ecstasy use. Methods: Baseline and 4-year follow-up data from a prospective-longitudinal community study of originally 3021 adolescents and young adults aged 14–24 years at baseline were assessed using the standardized M-CIDI and DSM-IV criteria. Results: Baseline cannabis users reported at follow-up more frequent access to ecstasy than cannabis non-users. Higher cannabis use frequencies were associated with increased ecstasy availability reports. Logistic regression analyses revealed that cannabis use and availability of ecstasy at baseline are predictors for incident ecstasy use during the follow-up period. Testing simultaneously the impact of prior cannabis use and ecstasy availability including potential confounders, the association with cannabis use and later ecstasy use was confirmed (OR = 6.3; 95% CI = 3.6–10.9). However, the association with ecstasy availability was no longer significant (OR = 1.2; 95% CI = 0.3–3.9). Conclusions: Results suggest that cannabis use is a powerful risk factor for subsequent first onset of ecstasy use and this relation cannot be sufficiently explained by availability of ecstasy in the observation period.

Magister Chirurgiae Dentium (MChD) / MChD (Oral Pathology) minithesis, Department of Oral and Maxillofacial Pathology, Faculty of Dentistry, University of Western Cape Among malignant lesions, lymphoma ranks second only to squamous cell carcinoma in frequency of occurrence in the head and neck. Lymphomas in HIV patients' are second in frequency to Kaposi's sarcoma as AIDS-defining tumours. About 50% of lymphomas in HIV patients are extranodal and more than half of these occur in the head and neck area. The number, variety and diagnostic complexity of lymphoma cases that have primarily arisen in the head and neck region has steadily increased in the surgical pathology service of the National Health Laboratory Services (NHLS) - Tygerberg. This observation is particularly relevant in the context of increasing HIV infection rates in the population of South Africa as demonstrated by a study in 2006 conducted by the Medical Research Council of South Africa. This is a retrospective study using the records of cases of head and neck lymphomas diagnosed at NHLS-Tygerberg over the last five years. The aim of this study is to investigate the prevalence of head and neck lymphomas (HNL) at NHLS-Tygerberg from January 2002 to December 2006. The objective of this study is to determine the frequency and types of HNL and to determine, if possible, an association between the incidence of HNL and the HIV status of the patients. Trends of prevalence in terms of gender, referral centres, HIV status, age of patients and site of presentation are also examined. The results of this study show an increase in the number of patients with HNL from January 2002 to December 2006. A significant increase is noted in the number of HIV positive patients documented each year, from 17% in 2002 to 33% in 2006. Western Cape- urban (WC-U) remains the largest referral center. A notable increase is seen, each year, in the number of patients referred to Tygerberg-NHLS from the Eastern Cape (EC) and Western Cape- rural (WC-R) areas. A significant number of HIV positive patients are referred from the Eastern Cape and Western Cape rural areas. The average age of disease presentation in the HIV positive group of patients is 35 years with the unknown group being 46 years and the HIV negative group being 54 years. The main categories of lymphoma that presented in HIV positive patients are plasmablastic lymphoma (PBL) and diffuse large B-celllymphoma (DLBCL), which together form 56% of cases. 26% of cases are Hodgkin's lymphoma (HL); the second largest group of HNL cases. Burkitt's lymphoma (BL) consists of 8% of cases. 7% of cases are T-cell lymphomas. 3% of cases are Mantle zone lymphomas. No cases of SLL and Follicular lymphomas (FL) are described in this group of patients. DLBCL and HL form 27% each of the cases in patients with a negative HIV status. A significant number of Follicular lymphomas (15%), small lymphocytic lymphoma (SLL) (9%), MALT (7%), and T-cell lymphomas (8%) are identified. No PBL are seen in this group of patients. The incidence of HNL at NHLS-Tygerberg has increased over the last five years. This trend parallels that seen in other developing countries such as Tanzania, Nigeria, Thailand and India. This increase is possibly due to an increase in the number of referrals to our center, an increase in the overall population of the Western Cape, an increase in the number of HIV positive patients and the high incidence of EBV infection in the general population of the Western Cape. Social issues, such as poverty, lack of adequate education, female dependence on partners, rural communities and the non-availability of anti-retroviral drugs (ARV) and highly active anti-retroviral therapy (HAART) to most of the population that require these drugs, are considered major contributing factors. A trend is noted in the increased number of female patients diagnosed each year with HNL. A predominance of DLBCL was identified in our series. This is consistent with previous reports and studies on HNL. The number of biologically aggressive lymphomas, such as DLBCL, Plasmablastic and Burkitt's lymphomas diagnosed each year, has also significantly increased. These were prevalent mainly in the HIV positive group of patients who were also younger compared to the HIV negative patients. The documented findings of this study will serve as a guideline for the estimation of head & neck lymphoma burden and risk assessment at NHLS- Tygerberg.

<p>U prvoj glavi dat je prikaz osnovnih pojmova koji se koriste u tezi, sa naglaskom na osnovne pojmove teorije grafova. U drugoj glavi daju se grafovski dokazi nekih geometrijskih problema. Na primer, dajemo dokaz poznate teoreme Silvestra. iz Kombinatorne geometrije, koristeći grafove. Treće poglavlje sadrži neke geometrijske dokaze u grafovima. Na primer, poznatu Turanovu teoremu, Pikovu teoremu i drugo. U četvrtom poglavlju dajemo metodičku transformaciju prethodnih problema. Neki od problema razloženi su na delove koji se mogu prezentirati od osnovne &scaron;kole do poslediplomskih studija. Peto poglavlje sadrži komentare prethodnog, kao i preporuku UNESCO-a iz 1992. godine o obrazovanju učenika u novom milenijumu.</p> / <p>Chapter 1 contains a shoot review of the basic notions which are used in the thesis with emphasis on the basic notions of graph theory. In Chapter&nbsp; 2we present graph proofs of some geometrical problems. For example, we present some proofs of the well known theorem of Sylvester, from Combinatorial geometry, using graph methods. In Chapter 3 we present some proofs in graphs which use geometry. For example, famous Turan&rsquo;s theorem, Pick&rsquo;s theorem and some others. Chapter 4 contains methodology transformations i.e. we apply the results from the previous chapters to the situations in the clossroom. In Chapter 5 we have some comments of UNESCO, from 1992, on education of children.</p>

Résumé : Cette thèse porte sur le rôle de deux expositions environnementales encore peu étudiées et pouvant influer sur l’incidence des hémopathies malignes (HME) de l’enfant : les rayons ultraviolets (UV) et les pesticides liés aux activités agricoles.Les leucémies (LA) et lymphomes de l’enfant sont les deux types principaux de HME et représentent respectivement environ 470 et 200 nouveaux cas par an en France. Leur prise en charge thérapeutique et leur survie ont fait d’immenses progrès, cependant la connaissance de leurs facteurs de risque est encore très partielle.Les études sur les effets des UV dans les cancers de l’enfant sont peu développées. Plusieurs méta-analyses récentes concluent à une augmentation du risque de LA chez l’enfant lors d’une exposition professionnelle ou domestique de la mère aux pesticides pendant la grossesse. L’exposition aux pesticides d’origine agricole a été moins étudiée, et les résultats sont hétérogènes.La première partie, écologique, de ce travail s’intéresse à l’exposition résidentielle aux UV. Une étude a été réalisée à partir des observations du Registre National des Hémopathies malignes de l’Enfant (RNHE) faites sur une longue période, entre 1990-2009 et sur l’ensemble de la France métropolitaine (9 082 cas de LA et 3 563 cas de lymphomes). Les données de l’exposition aux UV résidentiels étaient issues de la base EUROSUN. Une moyenne quotidienne d’exposition aux UV résidentiels sur l’ensemble de la période 1988-2007 à l’échelle communale a été considérée. Une augmentation significative de l’incidence des leucémies aiguës lymphoblastiques à précurseurs B (LAL-Pré B) chez les moins de 5 ans a été observée avec l’exposition aux UV résidentiels au moment du diagnostic. L’association n’était pas modifiée après une stratification par périodes ; par tranches d’unités urbaines ; par grandes régions, et par un indice de défaveur français. Une deuxième étude, individuelle, sur les UV ne trouvait pas de modification de l’association en prenant en compte le rôle de facteurs individuels soupçonnés d’être associés aux LAL et en regardant l’exposition à la naissance. Les données individuelles de ces facteurs provenaient de deux études cas-témoins en population générale, l’enquête ESCALE (2003-2004) et l’enquête ESTELLE (2010-2011).La dernière partie de la thèse se penche sur l’exposition résidentielle aux pesticides liés aux activités agricoles. Cette étude s’appuie sur les données du RNHE, recueillant 10 994 cas de LA et 4 301 cas de lymphomes sur la période 1990-2013. L’intensité de l’activité agricole dans le canton de résidence au moment du diagnostic a été choisie comme proxy de l’exposition aux pesticides. Cette intensité a été à partir des données cantonales du Recensement général Agricole de 2000. Dans cette première approche aucune association n’a été mise en évidence entre les HME et la part de Surface Agricole Utile (SAU) totale. Les analyses par grands types de cultures montrent, dans cette première approche, une association positive et significative entre l’intensité de cultures en oléagineux et l’incidence des LAL Pré-B et des lymphomes de Burkitt. Des analyses de sensibilité montraient des résultats hétérogènes par période d’étude. / Abstract: This thesis deals with the role of two environmental exposures not much studied and that could have an impact on the incidence of childhood hematological malignancies (CHM): ultraviolet radiation (UV) and agricultural pesticides.The two major diagnostic groups are acute leukemia (AL) and lymphomas and represent respectively around 470 and 200 new cases per year in France. Despite the progress made in improving therapeutic caring and survival, the etiology of these cancers remains largely unknown.There are very few studies on the association between UV and these cancers. Meta-analyses found a coherent association between childhood AL and parental professional or domestic pesticides exposure during pregnancy. However the association with residential exposure to agricultural pesticides has been less studied and results are heterogeneous.The first, ecological, part of the thesis addressed the associations between residential UV exposure at diagnosis and the incidence of types and subtypes of CHM in France. The 9,082 cases of acute leukemia (AL) and 3,563 cases of lymphoma diagnosed before the age of 15 years from 1990 to 2009 were provided by the French National Registry of Childhood Hematological Malignancies. UV data from 1988 to 2007 were extracted from the EUROSUN database. The annual daily average UV exposure of the children estimated at the municipalities of residence was considered. There was a significant increase in precursor B-cell acute lymphoblastic leukemia (PBC-ALL) in children aged less than 5 years with residential exposure to UV. The results remained stable in analyses stratifying by deprivation index or degree of urbanization of the municipalities.A second, individual, study found no change in the association between UV and PBC-ALL after taking into account the influence of suspected individual risk factors for ALL, and evaluated this association at birth. Individual data were collected by interviews in the ESCALE (2003-2004) and ESTELLE (2010-2011) nationwide case-control studies.The last part of this work focused on the residential exposure to agricultural pesticides. The 10,994 cases of AL and the 4,301 cases of lymphomas diagnosed among children less than 15 years old were obtained from the French National Registry of Childhood Hematological Malignancies over the period 1990-2013. Intensity of agricultural activities by Canton was used as a proxy of residential agricultural pesticides exposure. This proxy was estimated from the 2000 French agricultural census data. At this first step of the analysis, no associations were found between total agricultural area and incidence of CHM. Analyses by types of crops showed, at this first step, a significant association between oilseeds and PBC-ALL and Burkitt lymphoma. Sensitivity analyses evidenced heterogeneous results by time period.