Le travail présenté dans ce document est dédié à l’étude des désintégrations faibles de deux baryons beaux, Λ0b (|udb>) et Ξ0b (|usb>), et utilise des échantillons de données enregistrés par l’expérience LHCb en 2011 et en 2012. La production abondante des baryons Λ0b et Ξ0b dans les collisions proton-proton ainsi que la grande probabilité pour un quark b d’hadroniser en un baryon beau au Large Hadron Collider (LHC), donne à l’expérience LHCb l’opportunité d’étudier les désintégrations multicorps sans charme de baryons beaux. Une part significative de cette étude est dédiée aux mesures des rapports d’embranchements des désintégrations sans charme à quatre corps des baryons Λ0b et Ξ0b . Dans le Modèle Standard, ces désintégrations procèdent simultanément via les transitions de quarks b→u (à l’arbre) et b→d,s (transitions à courant neutre de type pingouin). La différence de phase faible induite par cette interférence est a priori une opportunité de rechercher la violation CP dans ces désintégrations de baryons beaux. De plus, ces désintégrations sans charme à quatre corps contiennent des structures résonantes, simultanément dans la région non-baryonique de basse masse à deux corps (i.e. les masses invariantes de π+π- , K± π∓ , K+ K- ) ainsi que dans la region baryonique de basse masse (i.e. les masses invariantes de pK, pπ). Par conséquent, la différence de phases fortes induite par l’interférence de ces amplitudes peut augmenter l’effet d’une asymétrie CP . Des mesures d’asymétries CP (∆ACP ) dans les modes de désintégrations discutés plus haut sont présentées dans ce document. Certaines sont produites dans des régions de l’espace des phases afin de favoriser la présence de structures résonantes. Ainsi, sept désintégrations inclusives de Λ0b et Ξ0b sont simultanément étudiées: Λ0b→pπππ, Λ0b→pKππ, Λ0b→pKKπ , Λ0b → pKKK, Ξ0b→ pKππ, Ξ0b→pKπK et Ξ0b→ pKKK ainsi que des désintégrations spécifiques qui incluent plusieurs résonances intermédiaires comme, par exemple, Λ0b → pa1 , Λ0b→∆++ K- π- ou Λ0b → Λ∗ (1520)0 φ0 . Six modes de désintégrations sont observés, parmi lesquels quatre sont établis pour la première fois. Six mesures de rapports d’embranchements sont réalisées, et des limites à 90% et 95% degré de confiance sont placées sur le rapport d’embranchement du mode Ξ0b→ pKKK pour lequel seul un indice de son existence est obtenu. Pour les mesures de ∆ACP réalisées, aucun signe significatif de violation de CP n’est observé. / The work presented in this document is focused on the study of weak decays of two b-baryons, Λ0b (|udb>) and Ξ0b (|usb>) , by making use of data samples recorded by the LHCb experiment in 2011 and 2012. The abundant production of Λ0b and Ξ0b baryons in proton-proton collisions as well as the large probability of the hadronisation of the b quark into b-flavoured baryons at the Large Hadron Collider gives the LHCb experiment the opportunity to study multibody charmless decays of b-baryons. A significant part of the study is dedicated to the measurements of the branching fractions of Λ0b and Ξ0b in 4-body fully-charged charmless decays. They proceed in the Standard Model simultaneously through b → u transition or Flavour Changing Neutral Current (FCNC) penguin transition b → s,d. The weak-phase difference induced by this interference pattern is a priori a good opportunity to search for CP violation in these very same baryons decays. Furthermore, these charmless multibobdy decays of b baryons contain rich resonance structures, both in the low-mass two-body nonbaryonic resonances (i.e. the π+π- , K± π∓ , K+ K- invariant mass) and the low-mass baryonic resonances (i.e. the pK, pπ invariant mass). Consequently, CP asymmetries might receive significant enhancement from the strong-phase differences coming from the interference of these amplitudes. Measurements of ∆ACP in the decay modes of interest are presented in this document, including measurements in specific phase space regions (that are meant to favour resonance structures). Henceforth, seven inclusive decays of Λ0b and Ξ0b are simultaneously studied, namely Λ0b→pπππ, Λ0b→pKππ, Λ0b→pKKπ , Λ0b → pKKK, Ξ0b→ pKππ, Ξ0b→pKπK and Ξ0b→ pKKK as well as additional specific decays that include intermediate resonances, such as, for instance, Λ0b → pa1 , Λ0b→∆++ K- π- or Λ0b → Λ∗ (1520)0 φ0. Six decay modes are observed, among which four are established for the first time. Six branching fractions measurements are thus performed, and 90% and 95% confidence level intervals, based on the Feldman-Cousins confidence belt inference described are placed on the branching fraction for the Ξ0b → pKKK decay mode, for which only a hint of its existence is obtained. No significant CP -violation effect is observed in any of the ∆ACP measurement performed.

Le calcul géométrique en modélisation et en CAO nécessite la résolution approchée, et néanmoins certifiée, de systèmes polynomiaux. Nous introduisons de nouveaux algorithmes de sous-division afin de résoudre ce problème fondamental, calculant des développements en fractions continues des coordonnées des solutions. Au delà des exemples concrets, nous fournissons des estimations de la complexité en bits et des bornes dans le modèle de RAM réelle. La difficulté principale de toute méthode de résolution consiste en les points singuliers isolés. Nous utilisons les systèmes locaux inverses et des calculs numériques certifiés afin d'obtenir un critère de certification pour traiter les solutions singulières. Ce faisant, nous sommes en mesure de vérifier l'existence et l'unicité des singularités d'une structure de multiplicité donnée. Nous traitons deux principales applications géométriques. La première: l'approximation des ensembles semi-algébriques plans, apparaît fréquemment dans la résolution de contraintes géométriques. Nous présentons un algorithme efficace pour identifier les composants connexes et pour calculer des approximations polygonales et isotopiques à l'ensemble exact. Dans un deuxième temps, nous présentons un cadre algébrique afin de calculer des diagrammes de Voronoi. Celui-ci sera applicable à tout type de diagramme dans lequel la distance à partir d'un site peut être exprimé par une fonction polynomiale à deux variables (anisotrope, diagramme de puissance etc). Si cela n'est pas possible (par exemple diagramme de Apollonius, VD des ellipses etc), nous étendons la théorie aux distances implicitement données.

The study examined the use of multiple representations such as the real world, written symbols, spoken symbols, diagrams and manipulatives by learners to promote the learning of percentages and fractions through social interaction. This investigation was carried out through a teaching and learning programme which was developed and implemented by me, the researcher. The effect of the implemented programme was the main focus of the research. The qualitative study was oriented in the interpretive paradigm – a paradigm that seeks to understand the meaning attached to human actions. Twenty learners participated in the implementation of the programme and 9 learners were selected for focus group interviews. The purpose of the interviews was to explore learners' understanding and feelings about the use of multiple representations in the learning of percentages and fractions through social interactions. The other tools employed in this study were pre-and-post diagnostic tests, observations, learners' work and a journal. The pre-test was used to determine learners' prior knowledge for the program design and implementation, while the post-test and learners' work were used to analyze the effect of the programme. Observations were used to investigate how multiple representations promoted or did not promote the learning of percentages and fractions. The teacher's journal was to record and reflect on any relevant information gathered on each lesson observed. The data shows that the effective use of multiple representations helped learners learn the concept of percentages and fractions better. Learners were able to look at representations in useful ways; multiple representations made some aspects of the concept clear; and multiple representations enabled learners to correct errors. Through the interaction between the teacher and learners, the following was found: all the learners changed words to change focus; learners made links between multiple representations; the learners deepened their concepts of percentages and fractions; learners could convert between fractions using multiple representations; learners could work out percentages of a quantity; and learners could express one quantity as a percentage of another. Furthermore, through the interaction between learners and learners all learners could identify more equivalent fractions of an initial fraction which was given to them; and they could increase and decrease a quantity by a given percentage. On the basis of this research, it can be concluded that the programme promoted the learning of percentages and fractions through three effective methodologies. The first methodology consisted of the effective use of multiple representations; the second methodology concerned the interaction between the teacher and learner during the learning process and the last methodology related to the interaction between the learners - interactions that were not strongly mediated by the teacher. I would recommend that teachers use these three effective approaches when teaching percentages and fractions to promote the learning of the concepts.

The main purpose of the research was to investigate the influence of scientific calculators on Grade 8 South African learner's understanding of fractions in learning mathematics. Quasi-experimental quantitative research methods were used. A sampling frame was selected using non probability sampling technique. A total of 15 learners in each group were randomly selected for an experimental and control group for the study. Both groups were taught fraction concepts by different teachers for the same duration and at the same time. The experimental group used a calculator as a learning aid while the control group used the traditional paper pencil method. Two tasks (post-test and assignment) were administered to both groups and a questionnaire to the experimental group. The results indicated that the scientific calculator has a positive influence in learner's conceptual understanding of fractions in mathematics as reflected in their performance. / Mathematics Education / M. Ed. (Mathematics Education)

BARROS, Maria José Costa dos Santos. Reaprender Frações Por Meio de Oficinas Pedagógicas: Desafio Para a Formação Inicial 2007. 134 f. Dissertação (Mestrado em Educação) – Universidade Federal do Ceará, Faculdade de Educação, Programa de Pós-Graduação em Educação Brasileira, Fortaleza-CE, 2007. / Submitted by Liliane oliveira (morena.liliane@hotmail.com) on 2012-08-06T13:10:17Z No. of bitstreams: 1 2007_DIS_MJCSANTOS.pdf: 750935 bytes, checksum: d7afa28aa9d76b4dc7c2ea98745b3619 (MD5) / Approved for entry into archive by Maria Josineide Góis(josineide@ufc.br) on 2013-11-14T13:18:32Z (GMT) No. of bitstreams: 1 2007_DIS_MJCSANTOS.pdf: 750935 bytes, checksum: d7afa28aa9d76b4dc7c2ea98745b3619 (MD5) / Made available in DSpace on 2013-11-14T13:18:32Z (GMT). No. of bitstreams: 1 2007_DIS_MJCSANTOS.pdf: 750935 bytes, checksum: d7afa28aa9d76b4dc7c2ea98745b3619 (MD5) Previous issue date: 2007 / The primary concern of the present research is fractions’ content, focusing on the relevance of such mathematical content to logical-mathematical acquisition. Firstly, a discussion on pedagogue’s early instruction is done, since this professional’s grounding enables her to teach Mathematics in early series and so it needs to be improved. The aim of this study is to observe how Fedathi’s Sequence methodology, connected with Didactic Engineering, can contribute to enhance the teaching and learning practices of fractions, theoretically and methodologically supported by pedagogical workshops and by the TelEduc Platform. Therefore, the main question this work answers is whether Fedathi’s Sequence methodology, connected with Didactic Engineering, contributes to decrease lacks in the apprehension of the concept of fraction. Participative research methodology scaffolded this work, since it was considered necessary to comprehend the action and participation of investigated subjects. These were students of the 7th semester of the Pedagogy course from the Faculty of Education belonging to Universidade Federal do Ceara. The analysis pointed to the following results: a) the students-teachers have a limited background on fractions; b) they do not know available methodologies to teach Maths; c) there is little contact with information technologies. Thus, the researchers worked to operate real changes in their relationship with fractions’ content, favoring the attainment of new schemes and restructuring other consolidated ones. It was possible to provide a discussion on the knowledge they already had and the knowledge they thought they had, observing these concerns within the re-elaboration of a new discourse of theirs. It was concluded, during the whole groundwork, that the investigated subjects, that is, future teachers made explicit the need for more study on the subject, in order to develop autonomy and a full reflection on the relation between docent’s theory and practice / O ponto de fulcro desta pesquisa é o conteúdo das frações, destacando-se a relevância deste conteúdo matemático para a aquisição do conhecimento lógico-matemático. Inicia-se este trabalho, fazendo uma discussão sobre a formação inicial do pedagogo, tendo em vista que o preparo deste profissional lhe permitirá ir para as salas de aula lecionar Matemática para as séries iniciais e precisa ser bem trabalhado. Objetiva-se com esta pesquisa observar de que modo as metodologias Seqüência Fedathi, aliadas à Engenharia Didática, podem contribuir para a melhoria do ensino e da aprendizagem de frações, tendo como suporte teórico e metodológico o uso de oficinas pedagógicas e da plataforma TelEduc. Neste sentido, responde-se com esta pesquisa a questão principal, móvel da realização deste estudo, que foi “verificar se as metodologias de ensino Engenharia Didática e Seqüência Fedathi contribuem para minimizar as dificuldades na apreensão do conceito de fração”. A metodologia de suporte foi a pesquisa-participante, por se considerar a necessidade de ação e participação dos sujeitos investigados. Os sujeitos investigados foram alunos do sétimos semestre do curso de Pedagogia da Faculdade de Educação da Universidade Federal do Ceará-FACED/UFC. As análises apontaram os seguintes resultados: a) os alunos-professores têm uma visão estreita sobre as frações; b) desconhecem as metodologias para o ensino de Matemática; c) têm concepções sobre o assunto que não são as reais; d) há pouco contato com as tecnologias de informação. Desta forma, trabalhou-se para operar mudanças reais em suas relações com o conteúdo das frações, promovendo a consecução de novos esquemas e reestruturando outros já consolidados. Foi possível promover uma discussão sobre o que eles já sabiam sobre o conteúdo e o que pensavam que sabiam, sendo observadas essas preocupações na reelaboração de um novo discurso por parte deles. Concluiu-se que, durante a formação, que os sujeitos investigados, ou seja, os futuros-professores, explicitaram a necessidade de estudar mais o assunto abordado, para desenvolver autonomia e ampla reflexão acerca da relação da teoria com a prática docente

The main aim of this thesis was to assess the status of soil organic carbon in newly shaped soils called Velká podkrušnohorská dump in the Sokolov district and evaluate the information in relation to the physic-chemical properties of soils. Another objective was to determine the relationship between the stable and labile fractions of soil organic carbon. The amount of soil carbon (stable fraction) was measured in the solid soil samples and there was the analysis of basic physic-chemical parameters of the soil performed. The highest concentration of soil carbon was measured in the stand alders and larch. The amount of soil carbon (labile fraction) was measured in the water extract. The highest values were measured in the stand silver birch and alders. Based on this data the quotient of the labile fraction from the stable fraction was determined and the correlation of the labile and stable fractions was made. It was found out that the higher quality soils are located at the leafy trees, but it leads to leaching of organic carbon. The bulk density and coarse-grained soil fraction was determined from the physical properties and these data were used to calculate the stock of soil organic carbon. The highest value was measured in deciduous forests with small-leaved linden, in coniferous forests with larch. The stocks of soil organic carbon were converted into codes by land cover categories and the thematic map was created. It was found out that the leafy trees are much more appropriate for forest restoration, because they are characterized by the rapid initial growth, easily degradable plant litter and stable form humus. Deciduous forests are also characterized by more developed soil substrate, which is however unstable.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work is the product of a project developed within the research line LP1 - Training, Knowledge and Professional Development of the Postgraduation Program on Education, of the Federal University of Santa Maria. The main objective was to investigate the training of teachers who teach mathematics in the early years of Elementary School in the context of the organization of fractions teaching for the fifth grade. To achieve it, we followed a teacher who teaches mathematics in the early years, participant of the PPOE / OBEDUC / CAPES project, in the movement of organization of fractions teaching, according to the Teaching Guiding Activity perspective - AOE (MOURA, 1996a, 1996b, 2001 2010).The specific objectives were deployed in formative and investigative. The first were aimed at the appropriation of theoretical and methodological assumptions that guided the actions of the research such as the Historical-Cultural Theory (VYGOTSKY, 1989, 1994, 2010, 2012), Activity Theory (LEONTIEV, 1978, 1983, 2012) and Teaching Guiding Activity, and also regarding the training of teachers of basic education (Cunha, 1999; PEPPER, 2007, 2009; LOPES, 2009; MOURA, 2000). The investigative objectives were: to investigate to what extent the AOE can become a general mode of action of the organization for the education of the teacher for the early years of elementary school; and identify factors that determine the change in the work quality of the teacher involved in this movement. The data were collected in 2013 in meetings recorded in audio and video, daily records and a semi-structured questionnaire. These data constituted episodes (MOURA, 1992) whose analysis showed that AOE can become the teacher training general organizational mode in the early years since: it is understood by the teacher as a possible way of overcoming the way mathematics has been traditionally taught; the teacher uses the theoretical assumptions which guide this methodological-theoretical proposition; and he/she is in teaching activity. Likewise, the factors that might determine the change in the teacher work quality, identified in the context of this research, were: mathematical learning; teaching learning and the new senses attributed to the teaching practice. / Este trabalho é o produto de um projeto desenvolvido no âmbito da linha de pesquisa LP1 - Formação, Saberes e Desenvolvimento Profissional do Programa de Pós-graduação em Educação da Universidade Federal de Santa Maria. O objetivo principal consistiu em investigar a formação de professores que ensinam matemática nos anos iniciais do Ensino Fundamental no contexto da organização do ensino de frações para o quinto ano. Para atingi-lo, acompanhamos uma professora que ensina matemática nos anos iniciais, participante do projeto Educação matemática nos anos iniciais do Ensino Fundamental: Princípios e práticas da organização ensino (PPOE/OBEDUC/CAPES), no movimento de organização do ensino de frações, segundo a perspectiva da Atividade Orientadora de Ensino - AOE (MOURA, 1996a, 1996b, 2001, 2010b). Os objetivos específicos foram desdobrados em formativos e investigativos. Os primeiros estiveram voltados à apropriação dos pressupostos teóricos e metodológicos que pautaram as ações da pesquisa tais como a Teoria Histórico-Cultural (VIGOTSKI, 1989, 1994, 2010, 2012), a Teoria da Atividade (LEONTIEV, 1978, 1983, 2012) e a Atividade Orientadora de Ensino, e também com relação à formação de professores da Educação Básica (CUNHA, 1999; PIMENTA, 1997, 2009; LOPES, 2009; MOURA, 2000). Os objetivos investigativos foram: investigar em que medida a AOE pode se converter em um modo geral de ação de organização do ensino para o professor dos anos iniciais do Ensino Fundamental; e identificar fatores que determinam a mudança de qualidade do trabalho do professor envolvido neste movimento. Os dados utilizados foram coletados no ano de 2013 em encontros gravados em áudio e vídeo, diários de registros e um questionário semiestruturado. Estes dados constituíram episódios (MOURA, 1992) cuja análise revelou que a AOE pode se converter em um modo geral de organização do ensino do professor nos anos iniciais na medida em que: a proposta for entendida pelo professor como uma possível superação da forma como a matemática vem sendo ensinada tradicionalmente; o professor se apropriar dos pressupostos teóricos que norteiam essa proposta teórico-metodológica; e o professor estiver em atividade de ensino. Da mesma maneira, os fatores, identificados no contexto desta pesquisa, que podem determinar a mudança de qualidade do trabalho do professor foram: a aprendizagem matemática; a aprendizagem da docência e os novos sentidos atribuídos à prática docente.

Made available in DSpace on 2014-07-29T15:16:27Z (GMT). No. of bitstreams: 1 Dissert Leslivan Ubiratan de Moraes.pdf: 723767 bytes, checksum: 88adcd404b3c30cc9f22d95b44bd13b3 (MD5) Previous issue date: 2008-04-16 / The jurubeba was identified that such species was Solanum scuticum M. Nee, from which pharmacognostic and morphanatomic data were not available to Goiás. Because of that, we tried some complementary data. For the morphoanatomic evaluation of the leaves some cuts were carried out as described by Kraus and Arduin (1997). For the phytochemical trial, it was used some methodologies as described by Costa (2001). With the phytochemical screening, were identified alkaloids, flavonoids, coumarins, anthraquinones and saponins in prospecting phytochemical. Both in phytochemical trial, as in the phytochemical prospection, it was found alkaloids. Due to the biological activities of these secondary metabolites, we obtained the alkaloid fraction, using the dust of the leaves, and we got the ethanol extract. The fractions were divided by polarity and they were evaluated by thin-layer chromatography. Microbiological evaluation was carried out to verify possible contaminants. Such evaluation did not reveal the presence of microorganisms, and it was raised the possibility of antimicrobiotic activity of the raw extract in twenty three strains of bacteria and in two yeasts. According to the antimicrobial tests, the extract presented some features, as the difficult of solubility in aqueous medium, and the best dilution was achieved in dimethyl sulfoxide (DMSO) 50%. These tests also demonstrated the difficult of the solubilization of the fractions, which it will be used in the experiments of Vero cells cultures. It was verified the low antimicrobial activity of the raw hidroethanolic extract. Of all the fractions, the alkaloid fraction presented the best solubility in DMSO 0.3%. So, it was proceeded the dilution and the evaluation of the alkaloid fraction in Vero cells, and it was evaluated morphology, viability and cellular proliferation. We finally verified the citotoxicity of the alkaloid fraction in the statistical analyses, and in the vitality test carried out by Trypan blue, and also in the morphological alterations compatible to citotoxity alterations. / A espécie de jurubeba estudada no presente trabalho é Solanum scuticum M. Nee, da qual não eram disponíveis dados farmacognósticos e nem morfoanatômicos para Goiás. Para a avaliação morfoanatômica das folhas S. scuticum realizaram-se cortes à mão livre e cortes permanentes como descrito por Kraus e Arduin (1997). Para realização de triagem fitoquímica utilizou-se as metodologias descritas por Costa (2001). Com na triagem fitoquímica, foram identificados alcalóides, flavonóides cumarinas, heterosídios antraquinônicos e heterosídios saponínicos na prospecção fitoquímica. O extrato etanólico das folhas foi obtido e apartir do mesmo procedeu-se o fracionamento por diferença de polaridade, e realizaram-se avaliações dos seus componentes através de cromatografia de camada delgada. Testou-se a esterelidade da droga em pó e a possível atividade antimicrobiana do extrato bruto hidoalcoólico de S. scuticum. Tal avaliação não revelou a presença de microrganismos, sendo levantada a possível atividade antimicrobiana do extrato bruto frente a vinte e três cepas de bactérias e duas de leveduras. Os testes demonstraram também a dificuldade de solubilização das frações, as quais seriam utilizadas nos experimentos de cultura de células da linhagem Vero. Sendo averiguada baixa atividade anti-microbiana do extrato hidroalcóolico bruto. Tendo em vista as atividades biológicas do grupo dos alcalóides procedeu-se à obtenção da fração alcaloídica a partir do pó das folhas. Pelos testes antimicrobianos o extrato apresentou características de difícil solubilidade em meio aquoso, a melhor diluição para emprego do extrato foi obtida em dimetilsulfóxido (DMSO) 50%. Das frações a que possuiu melhor solubilidade em DMSO foi à alcaloídica, na concentração de 0,3%. Assim procedeu-se a diluição e a avaliação da atividade da fração alcaloídica em células da linhagem Vero, avaliando-se a morfologia, viabilidade e proliferação celular frente aos tratamentos realizados. Verificando-se atividade citotóxica da fração alcaloídica tanto nas avaliações estatísticas do teste de vitalidade por azul de Trypan, quanto nas alterações morfológicas compatíveis com alterações citotóxicas.

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2015-05-21T15:04:30Z No. of bitstreams: 2 Dissertação - Luiza Toubas Chaul - 2015.pdf: 1642322 bytes, checksum: e56380dae120d4058880c94d9e953832 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2015-05-21T15:07:38Z (GMT) No. of bitstreams: 2 Dissertação - Luiza Toubas Chaul - 2015.pdf: 1642322 bytes, checksum: e56380dae120d4058880c94d9e953832 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2015-05-21T15:07:38Z (GMT). No. of bitstreams: 2 Dissertação - Luiza Toubas Chaul - 2015.pdf: 1642322 bytes, checksum: e56380dae120d4058880c94d9e953832 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2015-02-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / In recent years, interest in medicinal products derived from plants that exhibit antimicrobial activity has been intensified. The present study aimed to characterize drugs and herbal extracts, determine the polyphenol content, tannins, flavonoids, quantify the chosen marker and evaluate the antimicrobial activity of crude ethanolic extracts and fractions of Rosmarinus officinalis Linn., Origanum vulgare Linn. and Capsicum chinense Jack. against different microorganisms (Gram negative and Gram-positive bacteria, filamentous fungi and yeasts), pathogenic or not. The herbal drugs and extracts were obtained and physico-chemically characterized according to the Brazilian Pharmacopeia 5. Ed. The polyphenols, tannins and flavonoids contents were evaluated. A methodology to quantify rosmarinic acid from R. officinalis and O. vulgare was covalidated and a methodology to quantify capsaicin of C. chinense was validated. The fractions hexane, dichloromethane, ethyl acetate and aqueous were obtained by partition. Microdilution broth tests were performed to determine the minimum inhibitory concentration (MIC). It was found that the material is suitable for the study according to the Pharmacopoeias and that there is adequate quality control of the drug plant. Furthermore, the methodology for quantifying rosmarinic acid in both R. officinalis and in O. vulgare and methodology to quantitate capsaicin, have been validated and it is able to produce results with acceptable accuracy and precision in relation to the specifications of FDA and ANVISA. The content of rosmarinic acid found in R. officinalis and O. vulgare were 6.55 and 2.63%, respectively. The concentration of capsaicin in C. chinense was 1.84%. Regarding antimicrobial activity, most of the tested fractions were more effective than the crude ethanolic extracts (EEB), and the fractions that showed good activity to a greater number of microorganisms were hexane fraction of O. vulgare (OFH) and dichloromethanic fraction of R. officinalis (AFD) and C. chinense (PFD). Most of the tested fractions showed better activity against Gram-positive bacteria than against Gram-negative bacteria. The rosmarinic acid showed antimicrobial activity mainly against fungi. Polar fractions of O. vulgare also showed good antifungal activity and rosmarinic acid can be considered one of the possible compounds responsible for the antimicrobial activity. Capsaicin showed moderate activity against all strains of Listeria and can be one of the components responsible for moderate inhibition of this group of bacteria. The results of this study suggest that the AFD, OFH and PFD fractions show promising potential in the search for natural alternatives for conservation and control pathogens in food. / Nos últimos anos, o interesse por produtos derivados de plantas medicinais que apresentem atividade antimicrobiana tem sido intensificado. O presente estudo buscou caracterizar drogas e extratos vegetais, determinar o teor de polifenóis, taninos, flavonoides, quantificar o marcador escolhido e avaliar a atividade antimicrobiana de extratos etanólicos brutos e frações de Rosmarinus officinalis Linn., Origanum vulgare Linn., e Capsicum chinense Jack frente a diferentes micro-organismos (bactérias Gram-positivas e Gram negativas, fungos filamentosos e leveduriformes), patogênicos ou não. As drogas vegetais e os extratos foram obtidos e caracterizados físico-quimicamente de acordo com a Farmacopeia Brasileira 5. Ed. Os teores de polifenóis, taninos e flavonoides foram calculados. Covalidou-se metodologia para quantificar ácido rosmarínico em R. officinalis e O. vulgare e validou-se metodologia para quantificar a capsaicina em C. chinense. As frações hexânica, diclorometânica, acetato de etila e aquosa foram obtidas por partição a partir do extrato etanólico bruto. Foram realizados testes de microdiluição em caldo para a determinação da concentração inibitória mínima (CIM). A metodologia para quantificar o ácido rosmarínico, tanto em R. officinalis, quanto em O. vulgare, e a metodologia para quantificar a capsaicina, foram validadas e apresentam-se aptas a gerar resultados com exatidão e precisão aceitáveis em relação as especificações do FDA e ANVISA. Os teores de ácido rosmarínico encontrados no R. officinalis e O. vulgare foram de 6,55 e 2,63%, respectivamente. O teor de capsaicina em C. chinense foi de 1,84%. Com relação à atividade antimicrobiana, a maioria das frações testadas foram mais ativas que os extratos etanólicos brutos (EEB), sendo que as frações que apresentaram boa atividade frente a um maior número de micro-organismos foram a fração hexânica de O. vulgare (OFH) e as frações diclorometânica de R. officinalis (AFD) e C. chinense (PFD). A maioria das frações testadas apresentou uma atividade inibitória melhor frente a bactérias Gram-positivas do que frente a Gram-negativas. O ácido rosmarínico apresentou boa atividade antimicrobiana principalmente frente a fungos. Frações polares de O. vulgare também apresentaram boa atividade antifúngica, podendo o ácido rosmarínico ser considerado um dos possíveis compostos responsáveis pela atividade antimicrobiana. A capsaicina apresentou atividade inibitória moderada frente a todas as cepas de Listeria e pode ser um dos componentes responsáveis pela inibição deste grupo de bactérias. Os resultados obtidos neste estudo sugerem que as frações AFD, OFH e PFD mostram potencial promissor na busca de alternativas naturais para a conservação e o controle de patógenos em alimentos.

Le 36Cl est utilisé dans les études hydrologiques en raison de son caractère conservatif. Il apparaît cependant que le Cl- participe à un cycle biogéochimique complexe associé au turnover de la matière organique. Le flux de 36Cl atmosphérique a été déterminé (suivi mensuel des eaux de pluie sur deux ans) et varie saisonnièrement avec des valeurs accrues au printemps - été. L'importance de la période d'échantillonnage a été mise en évidence indiquant qu'une période de 6 mois est recommandée afin de lisser les variations saisonnières et les pics sporadiques du flux de 36Cl. Le flux atmosphérique moyen du 36Cl à notre site, constituant le flux d'entrée majoritaire dans son cycle biogéochimique, est de (75±6) atoms.m-2.s-1.La distribution du Cl et du 36Cl a été étudiée dans l’écosystème forestier grâce au développement des protocoles adéquats. 72% du Cl et 80% du 36Cl sont présents sous forme organique dans le sol alors qu'ils sont principalement sous forme inorganique dans la végétation. Les rapports mesurés dans la végétation (~ 200 x 10-15 at.at-1) sont similaires à ceux provenant des apports atmosphériques (~ 180 x 10-15 at.at-1) et ceux mesurés dans le sol sont un ordre de grandeur supérieur. Ces derniers augmentent significativement à 5-15 cm dans la fraction organique du profil de sol alors que dans la fraction inorganique une faible augmentation apparaît à 15-30 cm. Nous attribuons ces observations au recyclage du 36Cl du pic nucléaire des années 1950-1960. Ces résultats indiquent que la distribution du 36Cl diffère de celle du Cl suggérant des processus dynamiques d’immobilisation et de remobilisation du 36Cl liés au renouvellement de la matière organique. / 36Cl is widely used in hydrological studies since it is considered as a conservative tracer. However it appears that Cl- participates in a complex biogeochemical cycle linked to the organic matter turnover. The 36Cl atmospheric fallout rate has been determined (monthly record of rainwater samples during two years) and varies seasonally with higher values during spring – summer. The sampling period should at least span 6 months to avoid any biais in the fallout rate determination due to the monthly variations or any sporadic bursts of 36Cl. The mean 36Cl fallout rate at our site, corresponding to the main input of its biogeochemical cycle, equals (75±6) atoms.m-2.s-1. The distribution of Cl and 36Cl has been studied into the ecosystem thanks to the development of appropriate protocols.72% of the Cl and 80% of the 36Cl are contained in the organic fraction in soil while they are mainly in inorganic form in the vegetation. 36Cl/Cl measured in vegetation (~200 x 10-15 at.at-1) are within the range of the ones measured in the rainwater samples (~180 x 10-15 at.at-1), while the 36Cl/Cl ratios are 10 times higher in soil. 36Cl/Cl in soil increase significantly at a depth of 5-15 cm in the organic fraction while a slight increase is observed in the inorganic fraction at 15-30 cm deep. This suggests that 36Cl originating from the massive input of 36Cl introduced in the atmosphere more than 50 years as a consequence of nuclear tests, might still be recycling.These results emphasize that the distribution of 36Cl and Cl are not similar suggesting a possible occurrence of dynamic processes of 36Cl accumulation and release associated with the turnover of the organic matter.