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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Lecturers' perceptions on the value of the experience of completing a teaching portfolio

Grace, Elaine Lydia 01 1900 (has links)
A teaching portfolio allows lecturers to track their own growth and development in teaching and learning, as it helps to document their career’s journey. This study gained insight into this experience from the lecturers’ perspectives. The research paradigm was qualitative and the study used a sample of lecturers from an independent tertiary institution in Johannesburg. Personal interviews provided rich data and themes were developed from the data to answer the research questions concerning the value of doing a teaching portfolio. Lecturers’ perceptions provided clear evidence of the value of doing a teaching portfolio, because it developed their personal competence, knowledge, skills and higher-order thinking. However, the findings showed that the success of a teaching portfolio remained dependent on individual motivation and how the process was implemented. Any challenges experienced tended to negatively affect motivation, thereby decreasing the perceived value of a teaching portfolio. This study recommended that a teaching portfolio might offer a solution to some of the current education issues within the South Africa context, especially with regard to the lack of content knowledge and the disempowerment of teachers. / ʼn Onderrigportefeulje maak dit vir dosente moontlik om hul eie groei en ontwikkeling ten opsigte van onderrig en leer te monitor, omdat dit hulle help om hul loopbaan te dokumenteer. Hierdie studie gee insig in hierdie ervaring vanuit dosente se oogpunt. Die navorsingsparadigma was kwalitatief en die studie het ʼn steekproef van dosente van ʼn onafhanklike tersiêre instelling in Johannesburg behels. Persoonlike onderhoude het ryk data opgelewer en temas is op grond van die data ontwikkel om die navorsingsvrae oor die waarde van ʼn onderrigportefeulje te beantwoord. Dosente se persepsies was ʼn duidelike bewys van die waarde van ʼn onderrigportefeulje, omdat dit hul persoonlike bevoegdheid, kennis, vaardighede en hoërorde-denke ontwikkel. Die bevindinge het egter getoon dat die sukses van ʼn onderrigportefeulje steeds onderhewig is aan individuele motivering en hoe die proses geïmplementeer is. Enige uitdagings was geneig om ʼn negatiewe invloed op motivering te hê en sodoende die vermeende waarde van ʼn onderrigportefeulje te verlaag. Hierdie studie beveel aan dat ʼn onderrigportefeulje ʼn oplossing kan bied vir sommige van die opvoedingskwessies in die Suid-Afrikaanse konteks, veral met betrekking tot die gebrek aan inhoudkennis en die ontneming van onderwysers se mag. / Photefolio ya go ruta e kgontša bafahloši go latišiša kgolo le tšwetšopele tše e lego tša bona ka go goruta le go ithuta, ka ge e thuša go rekhota leeto la mošomo wa bona. Thutelo ye e hweditše tshedimošo maitemogelong a go tšwa tebelelong ya bafahloši. Dikgopolo ka ga nyakišišo e bile tša go hwetša tshedimošo ka go kwešiša le go lemoga mabaka a bothata gomme thutelo ye e dirišitše sampolo ya bafahloši go tšwa institušeneng ye e ikemetšeng ya morago ga marematlou go la Johannesburg. Ditherišano tša motho ka botee di tšweleditše datha ye bohlokwa gomme merero e hlagišitšwe go tšwa datheng go fa karabo ya dipotšišo tša dinyakišišo tše di lebanego bohlokwa bja go dira photefolio ya go ruta. Dikgopolo tša bafahloši di file bohlatse bjo bo kwešišegago bja bohlokwa bja go dira photefolio ya go ruta, ka gobane e godišitše, botsebi, tsebo, mabokgoni tša bona le mokgwa wa go nagana wa maemo a godimo. Le ge go le bjalo, dikhwetšo di bontšhitše gore katlego ya photefolio ya go ruta e dutše e ithekgile go tutuetšo ya motho le ka moo tshepedišo e phethagaditšwego. Ditlhohlo dife goba dife tšeo di itemogetšwego di bile le go huetša tutuetšo, ka gorealo tša fokotša boleng bjo bo lebeletšwego bja photefolio ya go ruta. Thutelo ye e šišintše gore photefolio ya go ruta e ka fa tharollo go tše dingwe tša ditlhagišo tša bjale tša thuto kemong ya Afrika Borwa, gagolo malebana le tlhokego ya dintlhatsebo, dikgopolo le melaotshepetšo tšeo di rutwago le go ithuta ka tšona gammogo le go se be le maatla ga barutiši. / Psychology of Education / M. Ed. (Psychology of Education)
82

Modelos de riscos aplicados à análise de sobrevivência / Hazard models on survival analysis

Perdona, Gleici da Silva Castro 25 August 2006 (has links)
Assumir suposições especiais sobre a função de risco tem sido a estratégia adotada por vários autores, com intuito de garantir modelos gerais e abrangentes, tanto para a análise de dados de sobrevivência quanto de conDabilidade. Neste estudo, modelos aplicados a dados da área de sobrevivência e conDabilidade são considerados. A Dnalidade deste estudo é propor modelos mais Pexíveis e/ou mais abrangentes de forma a generalizar modelos já existentes, bem como estudar suas propriedades e propor possíveis comparações entre os modelos via testes de hipóteses. Considera-se nesta tese, três classes de modelos baseados na função de risco (modelos de risco). A primeira classe apresenta-se como um caso particular do modelo de risco estendido (Louzada-Neto, 1999), formada por modelos que relacionam o parâmetro de escala a covariáveis, sendo que esse relacionamento pode ser considerado log-linear ou log-nãolinear. Considera-se um modelo particular onde a dependência do parâmetro de escala se dá de forma log-não-linear. Na segunda classe considera-se modelos que estão vinculados a dados de riscos competitivos, quando se tem ou não informação sobre qual tipo de risco foi responsável pela falha de um equipamento ou pelo óbito de um paciente. A terceira classe de modelos foi proposta, nesta tese, relacionando o contexto de modelos de longa duração. / Assuming special suppositions for the hazard function have been the strategy used for many authors in order to guarantee general and Pexible models for survival and reliability data. The present thesis considers two classes of hazard models, with the basic objective of proposing more Pexible models, studying their properties and proposing possible comparisons via hypothesis tests. We consider, three families of models where the struture was based in hazard function. The Drst class is a special case of the extented hazard model (Louzada, 1999). This class of models is composed by models with relationship between the scale parameter and the covariates could be log-linear or log-non-linear, we consider the log-non-linear. The second class is into the context of competing risk, where we do not known what kind of risk is responsable for the fail.or death. The third class, proposed in this work refers to a context of long term survivals. All the procedures were ilustrated in real datasets
83

Recarga gerenciada do aqüífero do Aeroporto Internacional Governador André Franco Montoro, Guarulhos/SP: estudo piloto do sistema solo-aqüífero. / Managed aquifer recharge of the Governor André Franco Montoro International Airport, Guarulhos/SP: pilot study of soil-aquifer system.

Okpala, Walter Onyebuchi 15 February 2011 (has links)
O Aeroporto Internacional Governador André Franco Montoro (GRU), São Paulo, depende inteiramente da água subterrânea para suprir sua demanda. Entretanto, a prática de extração excessiva, que aumenta continuamente para atender à demanda de um número cada vez maior de passageiros e às dificuldades envolvidas com a recarga natural do aqüífero, levou a Empresa Brasileira de Infraestrutura Aeroportuária (Infraero) a procurar outras fontes de abastecimento. Embora a busca de solução para o problema da escassez da água, passe pela opção de recarga gerenciada do aqüífero, a falta da experiência nacional nessa área restringe a tomada da decisão na adoção dessa prática no país. Objetivando contribuir com estudos de viabilidade técnica da recarga gerenciada de aqüíferos em geral e, em particular, do Aeroporto Internacional Governador André Franco Montoro, este trabalho tem o objetivo de verificar, em escala piloto, a capacidade do solo-aqüífero do aeroporto em tratar adequadamente o esgoto gerado localmente. Para atingir esse objetivo, uma área adequada foi selecionada entre as diversas avaliadas, para a construção de uma unidade piloto de recarga de aqüífero. No local selecionado, amostras indeformadas da camada não saturada foram coletadas, caracterizadas e, posteriormente, montadas em colunas experimentais especiais, pelas quais o esgoto foi infiltrado de maneira controlada. Como os resultados desta primeira fase experimental não foram adequadamente atendidos, foi decidido efetuar coletas de amostras indeformadas em uma segunda área do aeroporto, que indicou a existência de uma camada vadosa mais profunda, mas perfil de solo semelhante ao perfil anterior. Os ensaios de colunas foram efetuados com amostras de ambas as áreas, indicando que o solo superficial do aeroporto deverá ser eliminado, ou substituído por uma camada de areia grossa para permitir uma recarga gerenciada que permita a produção de águas com qualidade adequada para os usos preconizados. Os diferentes cenários utilizados nesta pesquisa envolveram a infiltração nas colunas de recarga com esgotos secundários produzidos no aeroporto, após passagem por duas lagoas de retenção, a infiltração do mesmo efluente tratado por um processo físico-químico de coagulação/floculação/sedimentação e pelo mesmo efluente das lagoas de retenção após tratamento por um sistema de membranas de ultrafiltração. Os resultados obtidos são considerados como resultados parciais, uma vez que toda a profundidade do aqüífero não foi utilizada e pelo fato de que, face às restrições acadêmicas vigentes o tempo disponível para a realização da pesquisa foi extremamente restringido. Entretanto, considera-se este trabalho como pioneiro, pelo fato dele se constituir na primeira pesquisa sobre recarga gerenciada no Brasil e, ainda, por fornecer subsídios teóricos e práticos para suportar outros estudos semelhantes que se farão necessários para compreender e promover a prática de recarga gerenciada de aqüíferos no Brasil. / The Governor André Franco Montoro International Airport, São Paulo, entirely depends on groundwater to meet its demand. However, excessive extraction practice which increase continuously in order to attend the demand of increasing number of passengers and the difficulty involved with natural recharge of its aquifer led the Federal Airport Administration Agency (Infraero) to search for other sources of water supply. Although the search for solution for water scarcity problem goes through managed aquifer recharge, lack of national experience in this area restricts decision making in adopting this practice in the country. Contributing to the technical feasibility studies of managed aquifer recharge in general and the Governor André Franco Montoro International Airport in particular, this research has the objective of verifying at the pilot scale level, the capacity of airport soil-aquifer in adequately treating wastewater generated locally. In order to reach this objective, an adequate location was selected within the alternatives evaluated for the construction of a pilot unit for aquifer recharge. Undeformed samples were collected from the unsaturated layer of the selected place, characterized and afterwards, recharged through special experimental columns with wastewater which was filtered in a controlled form. As the results of the first experimental phase were not adequately met, a decision was made to collect undeformed samples from a second location in the airport. The collection indicated the existence of deep unsaturated layer with the soil profile being similar to the profile of the soil layer from which the first samples were collected. The soil column tests were carried out with samples from both areas, indicating that superficial part of airport soil will be eliminated or substituted with a coarse sandy layer in order to permit a managed aquifer recharge which allows production of water that meets the quality of its required uses. Of the different scenarios verified in this research was infiltration of secondary wastewater produced at the airport through soil columns. Another was infiltration of wastewater after its pre-treatment by physicalchemical processes of coagulation/flocculation/sedimentation and still a third scenario, through pre-treatment of secondary effluent by ultrafiltration membrane. The results obtained are considered partial since the total aquifer depth was not used and the fact that academic restrictions limited excessively the time period of the research. However, considering this as a pioneer work, and the fact that it constitutes the first research about managed aquifer recharge in Brazil, and with it, bringing theoretical and practical contributions to support other similar studies which would be necessary in understanding and promoting managed aquifer recharge practice in Brazil.
84

Comunidade bacteriana dos biofilmes da fermentação alcoólica: estrutura, composição, suscetibilidade aos antimicrobianos e formação de biofilme em culturas puras / Bacterial community of biofilms from alcoholic fermentation: structure, composition, susceptibility to antimicrobials and biofilm formation in pure cultures

Dellias, Marina de Toledo Ferraz 03 February 2015 (has links)
A produção de etanol nas destilarias brasileiras é baseada na atividade fermentativa da levedura Saccharomyces cerevisiae que utiliza o caldo da cana-de-açúcar e/ou o melaço como substrato. Bactérias contaminantes da fermentação alcoólica competem com as leveduras pelos açúcares, afetando o rendimento do sistema produtivo e, consequentemente, causando perdas econômicas significativas às usinas. Biofilmes formados nos tanques de fermentação alcoólica agem como reservatórios de bactérias, contribuindo para contaminações persistentes e de difícil controle. Os biofilmes proporcionam aos seus habitantes certo grau de proteção contra diversas ameaças do meio, incluindo a ação dos antibióticos. Desta forma, o conhecimento da comunidade bacteriana dos biofilmes é fundamental para as medidas que visam o controle das contaminações na produção do bioetanol. No primeiro estudo, a composição e dinâmica da comunidade bacteriana foram determinadas pela análise de sequências do gene 16S rRNA de biofilmes com diferentes períodos de crescimento, correspondentes aos estágios iniciais de estabelecimento destes biofilmes dentro dos tanques de fermentação alcóolica Os resultados mostraram que estas comunidades foram compostas predominantemente pelas bactérias ácido-lácticas (LAB), com destaque para o gênero Lactobacillus. A visualização da estrutura dos biofilmes por microscopia eletrônica de varredura evidenciou que estes são formados por bactérias e leveduras (biofilmes mistos). No segundo estudo, a suscetibilidade aos antimicrobianos (monensina, virginiamicina e beta-ácido derivado do lúpulo) e a capacidade de formação de biofilmes em culturas puras foram avaliadas para isolados de Lactobacillus spp. provenientes de biofilmes (células sésseis) e de vinho bruto (células planctônicas) coletados dos tanques de fermentação. A partir dos resultados foi possível observar que as diferenças na suscetibilidade aos antimicrobianos e na habilidade de formar biofilmes foram estirpe-dependentes e que, em alguns casos, o perfil apresentado para algumas espécies mostrou-se relacionado à fonte de isolamento. Este foi o primeiro estudo sobre biofilmes contaminantes da fermentação alcoólica, em escala industrial, para a produção de etanol a partir da cana-de-açúcar / Bioethanol production in Brazilian distilleries is based on fermentative activity of the yeast Saccharomyces cerevisiae which uses sugarcane juice and/or molasses as a substrate. Bacterial contaminants of alcoholic fermentation compete with yeasts for sugars, affecting ethanol yield and consequently causing relevant economic losses to the fuel ethanol industry. Biofilms formed into fermentors act as bacterial reservoirs, contributing to persistent contaminations that are difficult to control. Biofilms provide a certain degree of protection for their inhabitants against some environmental threats, including antibiotics. Thus, understanding bacterial community within biofilms is essential for actions to control contaminations in bioethanol production. In the first study, composition and dynamic of bacterial community were determined by 16S rRNA gene sequences analysis of biofilms with different growth periods, corresponding to initial stages of biofilm establishment in fermentation tanks. Results showed that these communities were dominated by lactic acid bacteria (LAB), mainly of the genus Lactobacillus. Visualization of biofilm structure by scanning electron microscopy revealed a mixed-species biofilm composed by bacteria and yeasts. In the second study, susceptibility to antimicrobials (monensina, virginiamicina and beta-acids from hops) and capacity to form biofilm in pure culture were evaluated for Lactobacillus spp. isolated from biofilms (sessile cells) and wine (planktonic cells) collected from fermentors. The results showed that differences in the susceptibility to antimicrobials and the ability to form biofilms were strain-specific and, in certain cases, the response of some species was related to the isolation source. This was the first investigation of contaminant biofilms from sugarcane-based alcoholic fermentation on an industrial scale
85

Étude génétique de la voie sérotonine-N-acétylsérotonine-mélatonine et de ses anomalies dans la vulnérabilité aux Troubles du Spectre Autistique (TSA) et dans la prématurité / Genetic analysis of the serotonin-N-acetylserotonin-melatonin pathway and its abnormalities in Autism Spectrum Disorders (ASD) susceptibility and in preterm birth

Benabou, Marion 08 June 2017 (has links)
Des anomalies biochimiques de la voie sérotonine-N-acétylsérotonine-mélatonine ont été observées dans les Troubles du Spectre Autistique (TSA) et la prématurité. Cependant, les mécanismes moléculaires de régulation de cette voie et les causes des anomalies biochimiques observées dans ces maladies sont encore mal connus. Afin de mieux comprendre les bases génétiques de la voie sérotonine-N-acétylsérotonine-mélatonine, nous avons utilisé une approche de génétique quantitative au travers de deux populations d’étude indépendantes, dans lesquelles des paramètres de cette voie ont été mesurés. Ces deux cohortes, composées d’une part de plus de 250 familles avec autisme et plus de 300 témoins et d’autre part, de 183 nouveau-nés dont 93 nés très prématurés, incluent ainsi des individus présentant deux situations pathologiques différentes associées à des anomalies de cette voie. Une première étude de la voie sérotonine-N-acétylsérotonine-mélatonine dans les familles avec TSA a permis d’obtenir des estimations de l’héritabilité au sens strict, allant de 0,22 pour la mélatonine à 0,72 pour la N-acétylsérotonine (NAS). Des études d’association portant dans un premier temps sur une liste de 812 gènes candidats pour la régulation de la voie sérotonine-NAS-mélatonine et dans un second temps sur tout le génome, n’ont pas permis d’identifier des variants significativement associés aux traits biochimiques. Cependant, des études d’association par gènes ont permis d’identifier trois nouveaux gènes candidats (IL21R, JMJD7 et MAPKBP1) pour la régulation de cette voie dans les familles avec TSA ainsi qu’un nouveau gène (RAET1G) dans la cohorte de nouveau-nés prématurés et témoins. Enfin une étude biochimique des phénol-sulfotransférases (PST) dans les familles avec TSA a mis en évidence une faible activité enzymatique chez 29% des patients en comparaison avec les témoins (5ème percentile). Le séquençage et le génotypage du nombre de copies des gènes de la famille SULT1A1 n’ont pas permis d’identifier des variations génétiques associées aux TSA, à l’activité PST, ou aux taux de sérotonine et de mélatonine. En conclusion, ces résultats confirment la complexité de l’architecture génétique de la voie sérotonine-NAS-mélatonine. D’autre part, ils ont permis de mettre en évidence une héritabilité élevée de cette voie et d’identifier de nouveaux gènes candidats pour comprendre la diversité inter-individuelle de cette voie chez les personnes avec TSA, les enfants prématurés et la population générale. / Biochemical abnormalities of the serotonin-N-acetylserotonin-melatonin pathway have been reported in many clinical conditions such as Autism Spectrum Disorders and preterm birth. However, molecular mechanisms underlying this pathway regulation, as well as the causes of these biochemical abnormalities remain largely unknown. The aim of this study was thus to characterize the genetic basis of the serotonin-N-acetylserotonin-melatonin pathway. To do so, we used a quantitative genetic approach in two independent populations that were previously biochemically explored for this pathway. One cohort consisted of more than 250 families with ASD and more than 300 controls and the other was composed of 183 infants including 93 very preterm newborns. Both cohorts included individuals with clinical conditions associated with disruptions of the serotonin-N-acetylserotonin-melatonin pathway. Narrow sense heritability analysis of this pathway showed relatively high estimates, ranging from 0.22 for melatonin to 0.72 for N-acetyserotonin (NAS). First, candidate-gene association studies including 812 genes related to the serotonin-NAS-melatonin pathway, then genome-wide association studies were conducted. These analyses did not identify any variant associated at the genome-wide significance level. However, a gene-based approach identified three new candidate genes (IL21R, JMJD7 and MAPKBP1) for the regulation of the pathway in families with ASD as well as one gene (RAET1G) in the cohort of preterm and term newborns. Finally, a biochemical exploration of the phenol-sulfotransferases (PST) in families with ASD revealed a decreased enzyme activity in 29% of patients compared with controls (5th percentile). SULT1A1-4 genes were then sequenced and copy number variants (CNV) were genotyped. No genetic variant could be significantly associated with PST activity, melatonin and serotonin levels, or ASD status. In conclusion, these results confirm the complexity of serotonin-NAS-melatonin pathway genetic architecture. Furthermore, this study revealed high heritability of this pathway and identified new candidate genes to understand the inter-individual variability of this pathway in ASD, preterm birth and the general population.
86

Interprétation des pronoms clitiques objets chez les enfants avec TSA et chez les enfants avec TSL. : étude comparative en suivi du regard / Object clitic pronouns interpretation by children with ASD and by children with SLI : an eye-tracking comparative study

Léger, Elodie 10 November 2017 (has links)
Bien que les troubles du langage formel affectent une grande partie des enfants avec Trouble du Spectre Autistique (TSA), leur nature reste encore incertaine. Certaines études postulent que le trouble observable chez ces enfants est de même nature que celui dont souffrent les enfants avec trouble spécifique du langage (TSL), tandis que d’autres argumentent en faveur de deux troubles qui diffèrent dans leur étiologie. Au centre de ce débat réside la complexité à recueillir des données sur le langage chez les enfants avec TSA, notamment quand il s’agit de participer de manière active. Dans cette étude, nous explorons l’interprétation en temps réel des indices grammaticaux chez des enfants avec TSA monolingues francophones, en nous intéressant aux pronoms clitiques objets, dont la faible production en contexte obligatoire a été proposée comme marqueur du TSL pour le français. / It is well-known that children with Autism Spectrum Disorder (ASD) often have language impairment. However, the nature of this impairment is still largely unknown. Some studies hold that language impairment in children with ASD is of the same nature as impairment found in children with Specific Language Impairment (SLI), whereas others argue that SLI and language impairment in ASD may be different both in their structure and their etiology. At the heart of this debate lies the difficulty of assessing language abilities of children with ASD, especially when active participation is required. Moreover, to date, few studies have investigated formal aspects of language in children with ASD in languages other than English. In this study, we explore real-time interpretation of grammatical cues in French-speaking children with ASD, with a focus on object clitics.
87

On the Dynamics and Statics of Power System Operation : Optimal Utilization of FACTS Devicesand Management of Wind Power Uncertainty

Nasri, Amin January 2014 (has links)
Nowadays, power systems are dealing with some new challenges raisedby the major changes that have been taken place since 80’s, e.g., deregu-lation in electricity markets, significant increase of electricity demands andmore recently large-scale integration of renewable energy resources such aswind power. Therefore, system operators must make some adjustments toaccommodate these changes into the future of power systems.One of the main challenges is maintaining the system stability since theextra stress caused by the above changes reduces the stability margin, andmay lead to rise of many undesirable phenomena. The other important chal-lenge is to cope with uncertainty and variability of renewable energy sourceswhich make power systems to become more stochastic in nature, and lesscontrollable.Flexible AC Transmission Systems (FACTS) have emerged as a solutionto help power systems with these new challenges. This thesis aims to ap-propriately utilize such devices in order to increase the transmission capacityand flexibility, improve the dynamic behavior of power systems and integratemore renewable energy into the system. To this end, the most appropriatelocations and settings of these controllable devices need to be determined.This thesis mainly looks at (i) rotor angle stability, i.e., small signal andtransient stability (ii) system operation under wind uncertainty. In the firstpart of this thesis, trajectory sensitivity analysis is used to determine themost suitable placement of FACTS devices for improving rotor angle sta-bility, while in the second part, optimal settings of such devices are foundto maximize the level of wind power integration. As a general conclusion,it was demonstrated that FACTS devices, installed in proper locations andtuned appropriately, are effective means to enhance the system stability andto handle wind uncertainty.The last objective of this thesis work is to propose an efficient solutionapproach based on Benders’ decomposition to solve a network-constrained acunit commitment problem in a wind-integrated power system. The numericalresults show validity, accuracy and efficiency of the proposed approach. / <p>The Doctoral Degrees issued upon completion of the programme are issued by Comillas Pontifical University, Delft University of Technology and KTH Royal Institute of Technology. The invested degrees are official in Spain, the Netherlands and Sweden, respectively.QC 20141028</p>
88

Comunidade bacteriana dos biofilmes da fermentação alcoólica: estrutura, composição, suscetibilidade aos antimicrobianos e formação de biofilme em culturas puras / Bacterial community of biofilms from alcoholic fermentation: structure, composition, susceptibility to antimicrobials and biofilm formation in pure cultures

Marina de Toledo Ferraz Dellias 03 February 2015 (has links)
A produção de etanol nas destilarias brasileiras é baseada na atividade fermentativa da levedura Saccharomyces cerevisiae que utiliza o caldo da cana-de-açúcar e/ou o melaço como substrato. Bactérias contaminantes da fermentação alcoólica competem com as leveduras pelos açúcares, afetando o rendimento do sistema produtivo e, consequentemente, causando perdas econômicas significativas às usinas. Biofilmes formados nos tanques de fermentação alcoólica agem como reservatórios de bactérias, contribuindo para contaminações persistentes e de difícil controle. Os biofilmes proporcionam aos seus habitantes certo grau de proteção contra diversas ameaças do meio, incluindo a ação dos antibióticos. Desta forma, o conhecimento da comunidade bacteriana dos biofilmes é fundamental para as medidas que visam o controle das contaminações na produção do bioetanol. No primeiro estudo, a composição e dinâmica da comunidade bacteriana foram determinadas pela análise de sequências do gene 16S rRNA de biofilmes com diferentes períodos de crescimento, correspondentes aos estágios iniciais de estabelecimento destes biofilmes dentro dos tanques de fermentação alcóolica Os resultados mostraram que estas comunidades foram compostas predominantemente pelas bactérias ácido-lácticas (LAB), com destaque para o gênero Lactobacillus. A visualização da estrutura dos biofilmes por microscopia eletrônica de varredura evidenciou que estes são formados por bactérias e leveduras (biofilmes mistos). No segundo estudo, a suscetibilidade aos antimicrobianos (monensina, virginiamicina e beta-ácido derivado do lúpulo) e a capacidade de formação de biofilmes em culturas puras foram avaliadas para isolados de Lactobacillus spp. provenientes de biofilmes (células sésseis) e de vinho bruto (células planctônicas) coletados dos tanques de fermentação. A partir dos resultados foi possível observar que as diferenças na suscetibilidade aos antimicrobianos e na habilidade de formar biofilmes foram estirpe-dependentes e que, em alguns casos, o perfil apresentado para algumas espécies mostrou-se relacionado à fonte de isolamento. Este foi o primeiro estudo sobre biofilmes contaminantes da fermentação alcoólica, em escala industrial, para a produção de etanol a partir da cana-de-açúcar / Bioethanol production in Brazilian distilleries is based on fermentative activity of the yeast Saccharomyces cerevisiae which uses sugarcane juice and/or molasses as a substrate. Bacterial contaminants of alcoholic fermentation compete with yeasts for sugars, affecting ethanol yield and consequently causing relevant economic losses to the fuel ethanol industry. Biofilms formed into fermentors act as bacterial reservoirs, contributing to persistent contaminations that are difficult to control. Biofilms provide a certain degree of protection for their inhabitants against some environmental threats, including antibiotics. Thus, understanding bacterial community within biofilms is essential for actions to control contaminations in bioethanol production. In the first study, composition and dynamic of bacterial community were determined by 16S rRNA gene sequences analysis of biofilms with different growth periods, corresponding to initial stages of biofilm establishment in fermentation tanks. Results showed that these communities were dominated by lactic acid bacteria (LAB), mainly of the genus Lactobacillus. Visualization of biofilm structure by scanning electron microscopy revealed a mixed-species biofilm composed by bacteria and yeasts. In the second study, susceptibility to antimicrobials (monensina, virginiamicina and beta-acids from hops) and capacity to form biofilm in pure culture were evaluated for Lactobacillus spp. isolated from biofilms (sessile cells) and wine (planktonic cells) collected from fermentors. The results showed that differences in the susceptibility to antimicrobials and the ability to form biofilms were strain-specific and, in certain cases, the response of some species was related to the isolation source. This was the first investigation of contaminant biofilms from sugarcane-based alcoholic fermentation on an industrial scale
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Recarga gerenciada do aqüífero do Aeroporto Internacional Governador André Franco Montoro, Guarulhos/SP: estudo piloto do sistema solo-aqüífero. / Managed aquifer recharge of the Governor André Franco Montoro International Airport, Guarulhos/SP: pilot study of soil-aquifer system.

Walter Onyebuchi Okpala 15 February 2011 (has links)
O Aeroporto Internacional Governador André Franco Montoro (GRU), São Paulo, depende inteiramente da água subterrânea para suprir sua demanda. Entretanto, a prática de extração excessiva, que aumenta continuamente para atender à demanda de um número cada vez maior de passageiros e às dificuldades envolvidas com a recarga natural do aqüífero, levou a Empresa Brasileira de Infraestrutura Aeroportuária (Infraero) a procurar outras fontes de abastecimento. Embora a busca de solução para o problema da escassez da água, passe pela opção de recarga gerenciada do aqüífero, a falta da experiência nacional nessa área restringe a tomada da decisão na adoção dessa prática no país. Objetivando contribuir com estudos de viabilidade técnica da recarga gerenciada de aqüíferos em geral e, em particular, do Aeroporto Internacional Governador André Franco Montoro, este trabalho tem o objetivo de verificar, em escala piloto, a capacidade do solo-aqüífero do aeroporto em tratar adequadamente o esgoto gerado localmente. Para atingir esse objetivo, uma área adequada foi selecionada entre as diversas avaliadas, para a construção de uma unidade piloto de recarga de aqüífero. No local selecionado, amostras indeformadas da camada não saturada foram coletadas, caracterizadas e, posteriormente, montadas em colunas experimentais especiais, pelas quais o esgoto foi infiltrado de maneira controlada. Como os resultados desta primeira fase experimental não foram adequadamente atendidos, foi decidido efetuar coletas de amostras indeformadas em uma segunda área do aeroporto, que indicou a existência de uma camada vadosa mais profunda, mas perfil de solo semelhante ao perfil anterior. Os ensaios de colunas foram efetuados com amostras de ambas as áreas, indicando que o solo superficial do aeroporto deverá ser eliminado, ou substituído por uma camada de areia grossa para permitir uma recarga gerenciada que permita a produção de águas com qualidade adequada para os usos preconizados. Os diferentes cenários utilizados nesta pesquisa envolveram a infiltração nas colunas de recarga com esgotos secundários produzidos no aeroporto, após passagem por duas lagoas de retenção, a infiltração do mesmo efluente tratado por um processo físico-químico de coagulação/floculação/sedimentação e pelo mesmo efluente das lagoas de retenção após tratamento por um sistema de membranas de ultrafiltração. Os resultados obtidos são considerados como resultados parciais, uma vez que toda a profundidade do aqüífero não foi utilizada e pelo fato de que, face às restrições acadêmicas vigentes o tempo disponível para a realização da pesquisa foi extremamente restringido. Entretanto, considera-se este trabalho como pioneiro, pelo fato dele se constituir na primeira pesquisa sobre recarga gerenciada no Brasil e, ainda, por fornecer subsídios teóricos e práticos para suportar outros estudos semelhantes que se farão necessários para compreender e promover a prática de recarga gerenciada de aqüíferos no Brasil. / The Governor André Franco Montoro International Airport, São Paulo, entirely depends on groundwater to meet its demand. However, excessive extraction practice which increase continuously in order to attend the demand of increasing number of passengers and the difficulty involved with natural recharge of its aquifer led the Federal Airport Administration Agency (Infraero) to search for other sources of water supply. Although the search for solution for water scarcity problem goes through managed aquifer recharge, lack of national experience in this area restricts decision making in adopting this practice in the country. Contributing to the technical feasibility studies of managed aquifer recharge in general and the Governor André Franco Montoro International Airport in particular, this research has the objective of verifying at the pilot scale level, the capacity of airport soil-aquifer in adequately treating wastewater generated locally. In order to reach this objective, an adequate location was selected within the alternatives evaluated for the construction of a pilot unit for aquifer recharge. Undeformed samples were collected from the unsaturated layer of the selected place, characterized and afterwards, recharged through special experimental columns with wastewater which was filtered in a controlled form. As the results of the first experimental phase were not adequately met, a decision was made to collect undeformed samples from a second location in the airport. The collection indicated the existence of deep unsaturated layer with the soil profile being similar to the profile of the soil layer from which the first samples were collected. The soil column tests were carried out with samples from both areas, indicating that superficial part of airport soil will be eliminated or substituted with a coarse sandy layer in order to permit a managed aquifer recharge which allows production of water that meets the quality of its required uses. Of the different scenarios verified in this research was infiltration of secondary wastewater produced at the airport through soil columns. Another was infiltration of wastewater after its pre-treatment by physicalchemical processes of coagulation/flocculation/sedimentation and still a third scenario, through pre-treatment of secondary effluent by ultrafiltration membrane. The results obtained are considered partial since the total aquifer depth was not used and the fact that academic restrictions limited excessively the time period of the research. However, considering this as a pioneer work, and the fact that it constitutes the first research about managed aquifer recharge in Brazil, and with it, bringing theoretical and practical contributions to support other similar studies which would be necessary in understanding and promoting managed aquifer recharge practice in Brazil.
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Modelos de riscos aplicados à análise de sobrevivência / Hazard models on survival analysis

Gleici da Silva Castro Perdona 25 August 2006 (has links)
Assumir suposições especiais sobre a função de risco tem sido a estratégia adotada por vários autores, com intuito de garantir modelos gerais e abrangentes, tanto para a análise de dados de sobrevivência quanto de conDabilidade. Neste estudo, modelos aplicados a dados da área de sobrevivência e conDabilidade são considerados. A Dnalidade deste estudo é propor modelos mais Pexíveis e/ou mais abrangentes de forma a generalizar modelos já existentes, bem como estudar suas propriedades e propor possíveis comparações entre os modelos via testes de hipóteses. Considera-se nesta tese, três classes de modelos baseados na função de risco (modelos de risco). A primeira classe apresenta-se como um caso particular do modelo de risco estendido (Louzada-Neto, 1999), formada por modelos que relacionam o parâmetro de escala a covariáveis, sendo que esse relacionamento pode ser considerado log-linear ou log-nãolinear. Considera-se um modelo particular onde a dependência do parâmetro de escala se dá de forma log-não-linear. Na segunda classe considera-se modelos que estão vinculados a dados de riscos competitivos, quando se tem ou não informação sobre qual tipo de risco foi responsável pela falha de um equipamento ou pelo óbito de um paciente. A terceira classe de modelos foi proposta, nesta tese, relacionando o contexto de modelos de longa duração. / Assuming special suppositions for the hazard function have been the strategy used for many authors in order to guarantee general and Pexible models for survival and reliability data. The present thesis considers two classes of hazard models, with the basic objective of proposing more Pexible models, studying their properties and proposing possible comparisons via hypothesis tests. We consider, three families of models where the struture was based in hazard function. The Drst class is a special case of the extented hazard model (Louzada, 1999). This class of models is composed by models with relationship between the scale parameter and the covariates could be log-linear or log-non-linear, we consider the log-non-linear. The second class is into the context of competing risk, where we do not known what kind of risk is responsable for the fail.or death. The third class, proposed in this work refers to a context of long term survivals. All the procedures were ilustrated in real datasets

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