Made available in DSpace on 2015-05-14T13:21:45Z (GMT). No. of bitstreams: 1 parte1.pdf: 2505729 bytes, checksum: e872a92484e063cf1f264ba7b16d9e2e (MD5) Previous issue date: 2010-03-19 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This work proposes the use of digital images captured by a Webcam for determination of total acidity in red wines by means of an acid-base titration without using an external indicator. Digital images present the colour of the emergent radiation, which is complementary to the radiation absorbed by molecules of anthocyanines presents in wines. Each image, generated according to RGB system, yields a matrix of the values of the R, G and B components whose averages define a the colour value obtained as: 2R ⋅2G ⋅2B. This value was adopted as analytical response to build titrations curves based on digital images (DIB). For a more precise localization of the end point, titrations curves were generated on the basis of the second derivative values of the analytical response. Anthocyanines present different colours according to medium pH and, from the variation of the colour values of the images obtained during the titration of the red wines, the end point could be detected with precision. The official method recommends the use of potenciometric titration for determination of total acidity in red wines. This method requires a dilution of the sample before the titration that must be carried out until a fixed value of pH (8.2 8.4). In order to illustrate the feasibility of the proposed method titrations involving the determination of total acidity in ten red wines samples were carried out. Results were compared to the ones obtained by potenciometric titration used as reference method. No statistic difference has been observed between the results by applying the paired t-test at 95% confidence level. The proposed method yielded results with a better precision than the official method. These advantageous characteristics are attributed to the trivariate nature of the measures associated to digital images. / Neste trabalho, propõe-se o uso de imagens digitais, capturadas com uma Webcam, para determinação da acidez total de vinhos tintos por meio de titulação ácido-base sem a utilização de indicador externo. As imagens digitais apresentam a cor da radiação emergente que é complementar à da radiação absorvida por moléculas de antocianinas presentes nos vinhos. Cada imagem, gerada de acordo com o sistema vermelho-verde-azul (RGB), fornece uma matriz de valores dos componentes R, G e B cujas médias definem o valor de cor obtido como: 2R ⋅2G ⋅2B. Esse valor foi adotado como resposta analítica para a construção das curvas de titulação baseadas em imagens digitais (DIB). Para a localização mais precisa do ponto final, foram geradas as curvas de titulação com base nos valores da segunda derivada da resposta analítica. As antocianinas apresentam diferentes cores de acordo com o pH do meio e, a partir das variações do valor de cor das imagens obtidas durante a titulação dos vinhos tintos, o ponto final pôde ser detectado com precisão. O método oficial recomenda o uso da titulação potenciométrica para a determinação da acidez total de vinhos tintos. Este método requer diluição da amostra antes da titulação que deve ser efetuada até um valor fixo de pH (8,2-8,4). A fim de ilustrar a viabilidade do método proposto, foram realizadas titulações envolvendo a determinação da acidez total em dez amostras de vinhos tintos. Os resultados foram comparados com os obtidos pela titulação potenciométrica usada como método de referência. Constatou-se que não há diferença sistemática estatisticamente significativa entre os resultados, aplicando-se o teste t emparelhado ao nível de 95% de confiança. O método proposto produziu resultados com uma precisão melhor que a do método oficial. Essas características vantajosas da titulação DIB são atribuídas à natureza trivariada das medidas associadas às imagens digitais.

Justificativa e Objetivos: Acidose é uma desordem muito frequente em pacientes cirúrgicos. Neste cenário, permanecem incertas as implicações clínicas da acidose e características de cada tipo. Portanto, é relevante tentar elucidar o papel de cada tipo de acidose no prognóstico de pacientes cirúrgicos de alto risco. Método: Trata-se de estudo multicêntrico observacional prospectivo, realizado em três diferentes hospitais. Os pacientes que necessitassem no pós-operatório de cuidados intensivos foram incluídos no estudo consecutivamente. Pacientes com baixa expectativa de vida (câncer sem perspectiva de tratamento), pacientes com insuficiência hepática (child B ou C), insuficiência renal (Clearence de creatinina < 50 mL/min ou hemodiálise prévia), diagnóstico de diabetes previamente foram excluídos. Os pacientes classificados na admissão da UTI quanto ao tipo de acidose que desenvolviam no pós-operatório imediato foram acompanhados até 30 dias e alta hospitalar. Tal classificação avaliou acidose metabólica, pela quantificação da diferença de base menor que -4 mmol/L, anion gap corrigido pela albumina (AG) e lactato aumentados, quando maiores que 12 e 2 mmo/L, respectivamente. Então, os pacientes foram classificados como acidose metabólica hiperlactatemica, aumentado e normal (hipercloremica) anion gap corrigido pela albumina. Resultados: O total de 618 pacientes foram incluídos durante dois anos. A incidência de acidose metabólica foi 59,1% na UTI, porém 148 (23,9%) apresentaram hipercloremica, 131 (21,2%) revelaram hiperlactatemia, 86 (13,9%) AG aumentado e em 253 (40,9%) não ocorreu acidose metabólica. Dentre todas as cirurgias, pacientes de cirurgia gastrointestinal foram associados a maiores porcentagens de acidose metabólica 46,2% versus 19,8% sem acidose, P < 0,05. Interessantemente, acidose com hipercloremia apresentou mais altos valores de cloro na admissão da UTI 115,0 ± 5,7 meq/L (P < 0,05) e receberam maiores quantidades de solução fisiológica 0,9% no intraoperatório 3000,0 (2000,0 - 4000,0) mL (P < 0,05). Entretanto, apesar dos pacientes não apresentarem diferenças entre escores de gravidade (SAPS 3, SOFA e ASA), idade e tempo cirúrgicos, ocorreram diferenças em relação a complicações e mortalidade no pós-operatório quando os pacientes mantinham acidose após 12 horas de pós-operatório. Pacientes com lactato e AG aumentados no pós-operatório imediato apresentaram maiores complicações, seguido dos pacientes com hipercloremia, e os sem acidose, respectivamente 68,8%; 68,6%; 65,8% e 59,3%, P = 0,03. Cardiovascular e renal disfunções foram as principais complicações e o grupo hiperlactatemia mostrou maior incidência em comparação aos outros grupos. O mesmo foi verificado em relação à mortalidade hospitalar e em 30 dias de seguimento os grupos hiperlactatemia, AG aumentado, hipercloremicos e sem acidose foram respectivamente 30,1% (HR 1,61, IC 95% 1,02 - 2,53); 24,3% (HR 1,37, IC 95% 0,76 - 2,46); 18,4% (HR 1,55, IC 95% 0,90 - 2,67) e 10,3%, Log-Rank = 0,03. Conclusão: A incidência de acidose metabólica em pacientes cirúrgicos de alto risco no pós-operatório é elevada, principalmente a do tipo hipercloremia. Pacientes cirúrgicos que desenvolvem acidose metabólica, dependendo das características, apresentam piores prognósticos em relação aos pacientes sem acidose, além disso, este estudo demonstra que diferentes etiologias de acidose metabólica estão associadas com diferentes taxas de mortalidade e morbidade no pós-operatório / Background: Acidosis is a very frequent disorder in surgical patients. In this patient set there remains uncertainty the clinic implications from acidosis and characteristics postoperatively. Therefore, it is very important to evaluate the role of each acidosis type in outcome for high-risk surgical patients. Methods: Multicenter prospective observational study was performed in three different hospitals. The patients who needed postoperative ICU were involved in the study consecutively. Patients with low life expectancy (cancer without treatment), hepatic failure, renal failure, and diabetic diagnosis were excluded. The patients were followed until 30 days and hospital discharge. On ICU admission, immediately postoperative period, the patients were classified to each type of acidosis. The classification evaluated metabolic acidosis as base excess < -4 mmol/L and high albumin-corrected anion gap (AG) and hyperlactatemia, both > 12 and > 2 mmol/L, respectively. So, the metabolic acidosis classification patients were related to hyperlactatemic, high and normal (hyperchloremic) albumin-corrected anion gap. Results: The study enrolled 618 patients during 2 years. Overall, the acidosis incidence was 59.1% on ICU admission, 148 (23.9%) hyperchloremic, 131 (21.2%) hyperlactatemia, 86 (13.9%) a high anion gap and in 253 (40.9%) there was no metabolic acidosis. The hyperchloremic group presented the highest chlorine level, 115.0 ± 5.7 meq/L (P < 0.05) and highest administration of 0.9% physiologic solution intraoperatively, 3000,0 (2000,0 - 4000,0) mL (P < 0.05). However, in spite of patients didn\'t present difference in profile demographic and score prognostic, those who remain after 12 hours with acidosis, depend on groups classification in postoperatively showed greater ICU complications, respectively, hyperlactatemia group 68.8%; high anion gap 68.6%; hyperchloremic 65.8% and no acidosis 59.3%, P = 0.03. Cardiovascular and renal dysfunctions were the main complications and hyperlactatemia group showed the highest in all of them. The same was verified in related to 30 days follow-up and hospital mortality rate respectively 30.1% (HR 1.61, IC 95% 1.02 - 2.53) hyperlactatemic; 24.3% (HR 1.55, IC 95% 0.90 - 2.67) high anion gap; 18.4% (HR 1.37, IC 95% 0.76 - 2.46) hyperchloremic and 10.3% no acidosis group, Log-Rank = 0.03. Conclusions: Metabolic acidosis in surgical patients is a very important complication postoperatively, mainly hyperchloremic. Patients who developed metabolic acidosis postoperatively depend on group classification presented worst outcomes compared to no acidosis patients; this result showed that different kinds of acidosis represented different outcomes postoperatively

O principal interesse desta pesquisa foi descrever e analisar o resultado do aprendizado de conceitos relacionados ao tema equilíbrio químico buscando as concepções dos alunos, sobre aspectos gerais dos sistemas em equilíbrio químico e os aspectos gerais de sistemas ácido base em equilíbrio químico. Para isso acompanhamos e gravamos o áudio das aulas referentes ao ensino do conceito de equilíbrio químico ao longo das disciplinas de Química Geral II e Química Analítica I, no IQUSP. Ao longo das disciplinas aplicamos avaliações iniciais, progressivas e finais. Os resultados foram apresentados em três itens, no primeiro apresentamos a análise da avaliação inicial (AI) e avaliação final (AF), aplicadas na disciplina de Química Geral II (QGII), onde discutimos as concepções sobre aspectos gerais dos sistemas em equilíbrio químico. No segundo item, apresentamos a discussão da avaliação inicial (AI) e avaliação final (AF) aplicada na disciplina de Química Analítica I (QAI), nestas avaliações investigamos os aspectos gerais de sistemas ácido base em equilíbrio químico. No terceiro item, apresentamos a análise das respostas de um aluno, que respondeu todos os testes ao longo das disciplinas de Química Geral II e Química Analítica I, buscando uma reflexão sobre o processo de aprendizagem sobre os modelos do equilíbrio químico e os modelos ácido base, as constantes de equilíbrio químico, as forças de ácidos e bases, solução tampão, e as possíveis alterações promovidas em um sistema em equilíbrio químico, que são conceitos relacionados ao tema equilíbrio químico. A análise dos dados permitem concluir que, após as aulas de Química Geral, referentes ao tema, os alunos passaram a caracterizar corretamente o equilíbrio químico nos níveis macroscópicos e microscópicos, e a comparar o coeficiente de reação com a constante de equilíbrio para fazer previsões de uma mistura reacional. Entretanto, alguns alunos ainda não demonstram uma boa compreensão do significado e das possíveis aplicações da constante de equilíbrio, definindo-a apenas a partir da descrição da sua fórmula matemática. Também não relacionam a constante de equilíbrio químico com a temperatura, aplicando apenas o Principio de Le Chatelier para prever as alterações no sistema em equilíbrio químico. Observamos também que há uma dificuldade para descrever e explicar ácido e base, a partir de um nível eletrônico, usando o modelo de Lewis. Identificamos também algumas dificuldades conceituais e concepções alternativas, que permaneceram mesmo após instrução, tais como: confusões nos modelos que definem ácidos e bases, confusões com a aplicação dos conceitos dissociação e ionização e concepções alternativas referente ao equilíbrio ácido base. Com relação as alterações promovidas em um sistema em equilíbrio químico, observamos que os alunos, de forma geral, justificam o deslocamento do equilíbrio destacando principalmente o Princípio de Le Chatelier. Esperamos favorecer uma reflexão para o ensino e aprendizagem sobre aspectos relacionados ao tema Equilíbrio Químico / The main interest of this research was describe and analyze the results of the learning concepts about chemical equilibrium, seeking the general students concepts related to, chemical equilibrium and acid-base reactions in a stage of equilibrium. To do this we followed an recorded the classes which approach the equilibrium chemical systems at disciplines General Chemistry II and Analytical Chemistry I for IQUSP chemistry students. Initial e final tests were applied throughout disciplines. The results was showed in a three sets, we present first the analysis of initial evaluation (AI) and final evaluations, applied to General Chemistry discipline, discussing concepts about general aspects in chemical equilibrium systems. Then we showed discussing initial and final evaluations applied at analytical chemistry discipline, we search in this evaluations the concepts about an acid-base reactions in chemical equilibrium. In a third step we present the answers analysis of one single student that participated of all tests throughout General II and Analytical I disciplines, seeking a reflection about the learning process on the following topics, chemical equilibrium and acid-base models, the constants, the acid-base strengths and buffer solutions, and the possible changes promoted in a chemical equilibrium system that are important concepts related to the theme. The analysis of this dates suggesting, after the General Chemistry classes, that approach the theme, that students are able to correctly characterize the chemical equilibrium at macroscopic and microscopic levels and compare the coefficient and the constant of equilibrium chemical reactions to make previsions in this systems. However some students didn´t showed a fine concept about possible the applications of theses constants, and only defining through the mathematic relation. They also couldn´t not relationed the alteration in a equilibrium constant with the temperature, appling only the Le Chatelier Principle to make previsions about the alterations in a chemical equilibrium system. We also observe the difficult to analyze and explain the acid-base models starting from electronic level, using a Lewis model. We also identified some conceptual difficulties and misconceptions, which remained even after instructions, like: confusing model which explain acid-base models, confusing at applications of dissociation and ionization concepts and alternative conceptions about acid base equilibrium systems. In relation of promoted alterations that offered to a chemical equilibrium system, we observed the students, generally, justify the displacement of equilibrium particularly focusing on Le Chatelier Principle. This work favors discussions in teaching and learning aspects concepts about the chemical equilibrium.

Made available in DSpace on 2017-07-10T17:48:28Z (GMT). No. of bitstreams: 1 Aparecida_Oliveira.PDF: 706572 bytes, checksum: eaf8729b462e450590ef79f29daf8d4f (MD5) Previous issue date: 2012-02-10 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work aimed to study the electrolyte balance of diets on the metabolism of nitrogen balance, blood parameters, urinary pH and physiological response of barrows in the initial phase, in condition of stress and thermal comfort.. For the experiment were used 32 barrows in the early stages, with initial mean body mass of 18.5 ± 0.73. Distributed in experimental design of randomized blocks in a 2x4 factorial design with four replicates of 32 experimental units. The treatments consisted of four isonitrogenous diets with CP: 19.24% BE ration with 168 mEq/kg, R2: BE ration with 212 mEq/kg; R3: BE diet with 256 mEq/kg; R4: ration with EB 300 mEq/kg and two thermal conditions (comfort and stress). The parameters studied were nitrogen ingested, excreted in feces, urine excreted, absorbed, retained, retained/ingested, retained/absorbed, total excretion, protein intake (PBC), excreted in the feces (PBF) and urine (PBU) crude protein retained (PBR), net protein utilization (ULP), glucose, chloride, urea, creatinine, sodium (Na) and potassium (K) in blood plasma, urine pH, environmental conditions of the room, respiratory rate and temperature rectal cancer. The use of feed containing levels of EB between 168 and 300 mEq/kg did not influenced nitrogen balance, protein metabolism and blood parameters of pigs. Pigs exposed to 21 °C have higher consumption, fecal excretion of nitrogen, protein, sodium and potassium plasma than pigs reared under average temperature of 30 °C. Nitrogen retained: intake (%), net protein utilization (%), had higher creatinine values in the condition of thermal stress. The rations containing levels of EB between 168 and 300 mEq/kg to promote linear increase urine pH. The hours of daily observations promoted a positive linear effect (p <0.05) on the physiological parameter (rectal temperature and respiratory rate). The rise in rectal temperature was directly proportional to temperature. The respiratory rate showed an increase (57% above normal) in the heat stress condition / Este trabalho teve por objetivo estudar o balanço eletrolítico de rações sobre o metabolismo do balanço de nitrogênio, parâmetros sanguíneos, pH urinário e resposta fisiológica de suínos machos castrados na fase inicial, em condição de estresse e conforto térmico. Para o experimento foram utilizados 32 suínos machos castrados em fase inicial, com massa corporal média inicial de 18,5 ± 0,73. Distribuídos em delineamento experimental de blocos ao acaso em esquema fatorial 2x4 com quatro repetições totalizando 32 unidades experimentais. Os tratamentos foram constituídos de quatro rações isoprotéicas com 19,24% PB: R1: ração com BE 168 meq/kg; R2: ração com BE 212 meq/kg; R3: ração com BE 256 meq/kg; R4: ração com BE 300 meq/kg e duas condições térmica (conforto e estresse). Os parâmetros analisados foram Nitrogênio ingerido, excretado nas fezes, excretado na urina, absorvido, retido, retido/ingerido, retido/absorvido, excreção total, proteína bruta consumida (PBC), excretada nas fezes (PBF) e na urina (PBU), proteína bruta retida (PBR), utilização líquida de proteína (ULP), glicose, cloretos, uréia, creatinina, sódio (Na) e potássio (K), no plasma sanguíneo, pH da urina, condições ambientais da sala, frequência respiratória e temperatura retal. O uso de rações contendo níveis de BE entre 168 e 300 mEq/kg não influenciou o balanço de nitrogênio, metabolismo protéico e os parâmetros sanguíneos dos suínos. Os suínos expostos à temperatura de 21°C apresentam maiores consumo, excreção fecal de nitrogênio, proteína bruta, sódio e potássio plasmático do que suínos criados sob temperatura média de 30°C. O nitrogênio retido:ingerido (%), utilização líquida da proteína (%), Creatinina apresentaram maiores valores na condição de estresse térmico. As rações contendo níveis de BE entre 168 e 300 mEq/kg promovem aumento linear para o pH da urina. Os horários de observações diárias promoveram efeito linear positivo (p<0,05) sobre os parâmetros fisiológicos avaliados (temperatura retal e frequência respiratória). A elevação da temperatura retal foi diretamente proporcional a temperatura do ambiente. A frequência respiratória apresentou aumento (57% acima do considerado normal) na condição de estresse térmico

Le glycérol et le fructose sont des molécules qui peuvent être extraites facilement de labiomasse et en des quantités substantielles. Ce travail de recherche porte sur la déshydratationcomme moyen de valoriser ces composés. C’est dans ce but que des catalyseurs supportés suroxydes de zirconium et de titane, ainsi que des matériaux de type phosphate de calcium, ontété préparés et testés pour la réaction de déshydratation du glycérol en phase gazeuse. Desoxydes mixtes de niobium et cerium ainsi que des oxydes mixtes mésoporeux de Nb2O5-MeO2 (M = Ce, Zr, Ti) ont été également préparés et cette fois-ci testés pour la réaction dedéshydratation du fructose en milieu aqueux. Dans les deux cas, les propriétés acido-basiquesde surface des catalyseurs étudiés ont été corrélées à leur efficacité catalytique. / Glycerol and fructose are molecules that are readily available in substantial quantities fromthe biomass. In this work dehydration routes for valorization of these compounds wereinvestigated. Therefore, zirconia and titania based catalysts, and calcium phosphate materialswere prepared and evaluated in the glycerol dehydration in gas phase. Niobia-ceria mixedoxides and mesoporous Nb2O5-MeO2 (M = Ce, Zr, Ti) mixed oxides were prepared andtested in fructose dehydration reaction in aqueous phase. The surface acid-base properties ofthe studied catalysts were correlated to their catalytic performance.

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This diploma thesis deals with acid-base and electrolytic behavior of hyaluronan solutions at different ionic strength. Acid-base behavior of hyaluronan was investigated by acid-base titrations which were carried out with two different methods, acid and alkaline acid-base titration. Dissociation constants at different ionic strength at zero degree of dissociation and at 50% degree of dissociation were evaluated from the results of acid-base titrations. Dissociation constants obtained from acid acid-base titrations have values between 3,0 and 3,6. Dissociation constants obtained from alkaline acid-base titrations are not very informative because their values are much higher than the expected values. The study of degradation of hyaluronan during acid-base titration was performed to complete study of acid-base behavior. Electrolytic behavior of hyaluronan solution was performed by conductometric titrations in three different environments.

High-performance electromigration separation methods, capillary zone electrophoresis (CZE) and capillary isoelectric focusing (CIEF), have been applied to physico-chemical characterization of new synthetic low-molecular mass markers of isoelectric points. Amphoteric compounds on the basis of aminomethylnitrophenols, their derivatives and other structurally related substances were analyzed by CZE in a series of background electrolytes in a wide pH range, 1.86 - 11.18. From the measured pH dependencies of effective electrophoretic mobilities of analytes (beforehand corrected to reference temperature of 25 řC), their isoelectric points (pI) were determined. In addition, using the non-linear regression analysis of the above dependencies, acid-base dissociation constants (pKa) of ionogenic groups of selected analytes were calculated. Subsequently, the analytes with sharply defined isoelectric points were analyzed by CIEF. CIEF confirmed applicability of these compounds as markers of isoelectric points for calibration of pH gradient in CIEF in the determination of pI of amphoteric compounds, especially peptides and proteins. The determined pKa values of ionogenic groups in particular compounds will be utilized in the development of new pI markers with desired pI values.

and keywords Acid-base process PowerPoint presentation for secondary schools Abstract: At the present time, the requirements for the quality of nature sciences education in secondary schools are steadily increasing. However, the time approbation for teaching is relatively limited. Using presentations is going to be a possible way to increase the effectiveness of educational process and to take the full advantage of teaching methods which have positive effect on the motivation and activation of students. The goal of this Diploma work is to create a collection of teaching presentations in the MS PowerPoint application with a view to a part of general chemistry, i.e. the theme Acid-base process in the curriculum for four-year grammar schools or alternatively for higher years of longer grammar schools. These presentations are processed to be used in the real chemistry lessons in secondary schools. The subject matter of the curriculum is divided into five chapters, one chapter corresponds to one presentation. In order to facilitate the orientation of potential user every presentation is provided with an accompanying text. The electronic version of presentations is attached to Diploma work. Keywords: secondary school chemistry, general chemistry, acid-base process, student motivation, PowerPoint presentation

Ce travail de thèse s’inscrit dans le cadre de travaux menés en sciences du sport. Basé sur l’exploration des caractéristiques physiques et physiologiques, les performances techniques et physiques des joueurs de l’équipe de France de Rugby à 7, ont été étudiées au travers de l’analyse de tournois internationaux.Dans une première étude, nous avons observé l’impact de variables contextuelles sur les performances physiques et techniques des joueurs en match. Les résultats démontrent que le niveau de l'adversaire ainsi que le résultat du match influencent l’activité des joueurs.Ces derniers sont susceptibles de réaliser de meilleures performances physiques au cours de match dont l’issue est favorable. En effet, les joueurs augmentent la distance totale parcourue dans un match contre un adversaire plus faible. Pour la première fois en Rugby à 7, nous avons montré que les performances techniques sont elles aussi influencées lorsque les joueurs de l’équipe de France jouaient contre une équipe plus forte. En effet, nous avons observé des diminutions du nombre de passes et de situations où les joueurs sont porteurs de balle.Au travers d’une approche physiologique, une deuxième étude a appréhendé les réponses métaboliques individuelles des joueurs de l’équipe de France durant un tournoi international. Les résultats ont montré des relations significatives entre les concentrations de lactate et les pics d’activité enregistrés dans les trois dernières minutes de jeu, ce qui suggère que la capacité à fournir de l'énergie via la voie de la glycolyse est une exigence fondamentale dans cette discipline. L'équilibre acido-basique modifié de façon significative en fin de match, indique que les joueurs doivent être capables de tolérer un niveau important d'acidose due à une forte sollicitation énergétique lors des matchs internationaux.Enfin, notre dernière étude s’est centrée sur les actions de haute intensité effectuées en match. Ces derniers résultats de recherche ont permis de démontrer qu’un joueur réalise en moyenne ~26 actions de haute intensité par match. De plus et pour la première fois dans cette discipline, nous avons montré qu’environ 4 séquences de répétitions d’actions de haute intensité sont comptabilisées en match, dont la durée moyenne est d’environ 40 secondes et comprennent des temps de récupérations inférieurs à 9 secondes. Ainsi, le Rugby à 7 peut être considéré comme un sport collectif de répétitions d’efforts intenses.Pour conclure alors, ces travaux de thèse vont permettre aux entraîneurs et préparateurs physiques de Rugby à 7, de pouvoir s’inspirer de nos résultats pour planifier et mettre en œuvre des entraînements spécifiques aux exigences du Rugby à 7. / Our thesis research fits within the framework of sport science. Based on the exploration of physical and physiological characteristics, technical and physical performance achieved by the French Rugby 7’s team, were studied through the analysis of international tournaments.In the first study, we observe the impact of contextual variables on the physical and technical performance of players during a Rugby 7’s game. The results demonstrate that the level of the opponent and the match result influence the activity of players. Players are likely to perform better physically during a game for which the outcome is favorable. They increase the total distance run in a game against a weaker opponent. For the first time in Rugby 7’s, we were able to show that technical performance is also affected whilst playing against a stronger opponent as there is a decrease in the number of passes and the number of situations where players are ball carriers.Through a physiological approach, the second study focuses on the individual metabolic responses of players during an international Rugby 7’s tournament. The results show a significant relationship between lactate concentrations and peaks activity recorded in the last three minutes of play, suggesting the ability to provide energy via the glycolytic pathway as a fundamental requirement in this sport. Also, the acid-base balance significantly changes towards the end of a game showing that Rugby 7’s players must be able to tolerate a high level of acidosis because the high amount of energy needed for games at an international level.Finally, our last study focuses on high intensity actions done during a Rugby 7’s game. The results show that a player does on average ~26 high intensity actions per game. In addition and for the first time in this sport, we show that approximately 4 sequences of repeated high intensity actions are recorded in a game, the average duration is 40 seconds and includes a time of recovery of under 9 seconds. Thus, Rugby 7’s may be considered as a team sport of repeated high intensity actions.To conclude, this thesis will allow Rugby 7’s coaches and fitness coaches, to better plan and prepare specific trainings that would be adapted to Rugby 7’s.