• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 9
  • 9
  • 7
  • 4
  • 1
  • Tagged with
  • 33
  • 8
  • 8
  • 6
  • 5
  • 4
  • 3
  • 3
  • 3
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • 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.
1

Kinetic studies on electron-transfer reactions of cytochromes and ferredoxins

Harshani de Silva, D. G. A. January 1987 (has links)
No description available.
2

Automatic analysis of holographic interferograms

Hunter, J. C. January 1987 (has links)
No description available.
3

The effect of heat transfer on the dispersion of cold dense gases

Tasker, M. January 1987 (has links)
No description available.
4

polymer grafted TEMPO as a mediator for cellulose oxidation

Fu, Qiang January 2017 (has links)
TEMPO-mediated oxidation is a widely used approach to introduce aldehyde and carboxyl groups on cellulose. In the conventional TEMPO-mediated oxidation, the mediator TEMPO is a small molecule. Previous research in our group advanced TEMPO-mediated oxidation by grafting TEMPO onto high molecular weight poly(acrylic acid) and polyvinylamine. The polymer grafted TEMPO-mediated oxidation required less TEMPO and had a lower environmental impact. This thesis describes new insights into the role of polymer grafted TEMPO as mediator for cellulose oxidation. The redox-activity of grafted TEMPO was analyzed by electrochemical techniques and the resulting aldehyde densities on cellulose surfaces, produced by polymer grafted TEMPO, were determined with a fluorescence-labeling method. The properties of polymer grafted TEMPO solutions are essential to understanding the role of grafted TEMPO as the oxidation mediator. TEMPO substitution compacted both the conformation of poly(acrylic acid) and polyvinylamine due to the lower hydrophilicity of the TEMPO substituents. Poly(acrylic acid-g-TEMPO) (PAA-T) solutions phase separated over the pH range 2-4, whereas at lower and higher pH the polymer was water-soluble. The phase separation at low pH was proposed to be the combined result of the hydrophobic contributions of the TEMPO moieties and electrostatic interactions between the acid-induced cationic TEMPO species and the anionic ionized carboxyl groups. Polyvinylamine-g-TEMPO (PVAm-T) was water-soluble over a larger pH range (pH 1-9) due to the ionization of the amine groups. Both the PAA-T and PVAm-T were slightly surface active. Multilayer films composed of PVAm-T and poly(styrene sulfonate) were stable and redox-active. Charge transport in the redox multilayer films was realized through TEMPO-to-TEMPO electron hopping between neighboring TEMPO moieties. Only 20-30% of TEMPO moieties were redox-active, reflecting the requirement that TEMPO moieties must be closer than ~ 0.6 nm for electron hopping to occur. The redox multilayer films displayed significant interpenetration of layers. The ability of PVAm-T to spontaneously adsorb onto negatively charged surfaces in aqueous solutions provides an easy route to TEMPO-rich surfaces for other applications. Specific attention was focused on the role of PVAm-T as mediator for cellulose oxidation in the presence of laccase. Positively charged PVAm-T formed colloidal complexes with negatively charged laccase. The behaviors of PVAm-T/laccase mixtures displayed the classic features of polyelectrolyte complexes formed between oppositely charged polyelectrolytes. For the first time, electrochemical quartz crystal microbalance with dissipation (EQCM-D) measurements were used to characterize the redox properties of the adsorbed PVAm-T/laccase complexes. The role of PVAm-T as mediator for cellulose oxidation depended upon TEMPO-to-TEMPO electron transfer within PVAm-T/laccase colloidal complexes. The aldehyde density on oxidized cellulose surfaces scaled with the square root of surface molar density of redox-active TEMPOs which, in turn, was a linear function of TEMPO degree of substitution in PVAm-T. As a result, the aldehyde density on cellulose surfaces, generated by PVAm-T/laccase oxidation, can be controlled by varying the TEMPO degree of substitution in PVAm-T. / Thesis / Doctor of Philosophy (PhD)
5

Study on mass transfer and turbulence in large pipe flow using limiting current density technique

Xie, Qingqing January 1997 (has links)
No description available.
6

O Caso Maria: Implicações e desdobramentos da instituição de um espaço de escuta psicanalítico / Marias case: implications and developments of the institution of a psychoanalitic listening space

Alvares, Rita de Cassia Mendes 08 September 2016 (has links)
A tese discute as implicações e os desdobramentos transferenciais da instituição de um espaço de escuta psicanalítico na sede de uma organização não governamental que abrigava um projeto de Centro da Juventude num bairro da zona sul do município de São Paulo. Depois de abordar a gênese da aposta no desejo de escuta, a autora problematiza o processo de construção desse espaço, dentro do qual surgiu a escuta do caso Maria, marcada pela presença do traumático associado ao silenciamento do sujeito, e paradoxalmente, ao que retorna na compulsão à repetição, no agir atualizado na relação transferencial. A autora examina, também, o que no contexto social pode operar de captura do sujeito e reforçar as posições de sacrifício impostas pelos imperativos superegoicos. A partir da experiência de escuta do traumático no caso Maria, a autora defende o ponto de vista de que a disponibilização de um espaço de escuta psicanalítico, sustentado pela presença do analista, pode suscitar a emergência da fala do sujeito, a elaboração de um pedido de escuta, e propiciar alguma diferenciação das posições que marcam lugares de estagnação / The thesis discuss the transferencial implications and developments of the institution of a psychoanalitic listening space in the headquarters of a non-governmental organization that housed the project of a Youth Center in a neighborhood of the south area of the city of São Paulo. After approaching the genesis of the bet on listening desire, the author problematize the construction process of this space, within wich arose the listening of Maria case, marked by the presence of the traumatic associated with the silencing of the subject, and, paradoxically, with what returns in the repetition compulsion, in the <> updated in the transference relationship. The author examine also, of what in the social context, can operate as a capture of the subject, and reinforce the positions of sacrifice imposed by the super egoic imperatives. Starting from the listening experience of traumatic in the Maria case, the author defends the view that the provision of a psychoanalitic listening space, supported by the presence of the psychoanalyst, may give rise to the emergence of the speech of the subject, to the elaboration of a demand for listening, and propitiate some differentiation in the positions that mark places of stagnation
7

A utilização do paradigma de equivalência de estímulos para modificar a preferência alimentar / The use of stimulus equivalence paradigm to modify preference food.

Straatmann, Gisele 05 March 2008 (has links)
O presente trabalho teve como objetivo verificar a aquisição de função simbólica de expressões emocionais por nomes de alimentos verdadeiros e fictícios em adolescentes, por meio do paradigma de equivalência de estímulos. No Estudo I foram ensinadas relações entre as faces humanas expressando alegria e neutralidade com nomes de alimentos verdadeiros pelo procedimento de matching-to-sample simultâneo, diferindo a quantidade de treino em três grupos experimentais (segundo e terceiro grupo com supertreino). Os retratos faciais (conjunto A) foram relacionados a conjuntos de estímulos abstratos (conjuntos B e C); estímulos do conjunto B foram relacionados a nomes de alimentos (D). Portanto, as relações AB, AC e BD foram treinadas. Ao final foi conduzido o teste de equivalência CD/DC. Para avaliação inicial e final dos alimentos, foi utilizado um questionário com cinqüenta nomes de alimentos anexados a uma escala de avaliação de cinco pontos composta de expressões faciais e um teste de preferência alimentar com dez alimentos selecionados do questionário. Cinqüenta e cinco participantes da quinta série do ensino fundamental de escolas públicas e particulares concluíram o Estudo I. Trinta e cinco participantes mostraram desempenhos consistentes na fase de estabelecimento de equivalência de estímulos (nove do Grupo 1, onze do Grupo 2 e quinze do Grupo 3). Entre esses participantes, o alimento treinado com a face alegre foi avaliado em ambos os instrumentos como mais agradável por sessenta e seis porcento dos participantes do primeiro grupo e quarenta e cinco porcento do terceiro grupo. No segundo grupo, quarenta e cinco porcento avaliaram mais positivamente este alimento no pós teste de preferência alimentar. Em relação à face neutra feminina, os participantes dos Grupos 2 e 3 apresentaram avaliações finais mais positivas nos instrumentos finais . Porém, em relação ao alimento equivalente à face neutra masculina, destaca-se uma redução na avaliação do pós-teste de preferência nos Grupos Experimentais 2 e 3. O Estudo II teve como objetivo verificar se a transferência de função ocorreria se fossem utilizados nomes fictícios de alimentos relacionados com expressões esquemáticas de alegria, neutralidade e tristeza pelo procedimento de matching-to-sample com atraso. Os estímulos que diferiram do Estudo I foram os dos conjuntos A e D, compostos por faces esquemáticas e nomes fictícios de alimentos (capira, fulito e piteba), respectivamente. Um questionário com uma escala de cinco pontos de expressões esquemáticas foi usada como pré e pós teste. Trinta e seis participantes concluíram o Estudo II, dos quais vinte e cinco apresentaram desempenhos consistentes no teste de equivalência. A interação entre os questionários versus alimento teve um efeito significativo (p<0,001) no grupo de participantes que atingiram o critério de equivalência. Os participantes aumentaram as avaliações finais de capira (treinado com a face alegre), mantiveram avaliações finais muito próximas às iniciais no alimento fulito (treinado com a face neutra) e, diminuíram consideravelmente o pós teste do alimento piteba (treinado com a face triste). / The aim of the present study was to verify the acquisition of symbolic properties of facial expressions of emotion for real and fictitious food names in adolescents, using a stimulus equivalence paradigm. In Experiment 1, conditional relations between facial expressions (one of happiness and two expressing emotion neutrality) and real food names were trained by simultaneous matching-to-sample procedure. Three experimental groups differed only on the amount of training (Group 2 and 3 with overtraining). Pictures of facial expressions (Set-A) were related to abstract line drawing stimulus (Set-B and Set-C); C stimuli were related to food names (D). So, the AB, AC and BD relations were trained. Finally, they received the equivalence tests CD/DC. The participants were asked to rate the foods names for pleasantness in the beginning and in the end of the experiment by a questionnaire with fifty food names. These were linked to a five point scale of facial expressions and a preference test that had ten food names selected from the questionnaire. Fifty five participants that were in the fifth grade of public and private schools concluded Experiment I. Thirty five participants demonstrated equivalence (nine in Group 1, eleven in Group 2 and 15 in Group 3). The food trained with the happy face was valued in both final instruments of evaluation of the food preference as more pleasant by sixty six percent of the Group 1 participants and forty five percent of the Group 3. In Group 2, forty five percent valued as more pleasant this food only in the final evaluation of the preference test. The food related to the feminine neutral face showed more positive evaluations in Groups 2 and 3. On the other hand, the food equivalent to the masculine neutral face had a reduction in the food preference test in Groups 2 and 3. Experiment II aimed to verify if the transfer of function would happen if fictitious names of foods related to facial expressions of happiness, neutrality and sadness were used via delayed matching-to-sample procedure. Stimuli of Set-A and Set-D were different from Experiment I and had schematic expressions and fictitious food names (capira, fulito and piteba), respectively. A five point scale questionnaire of schematic expressions was used to value the fictitious names of foods in the beginning and in the end of the experiment. Thirty six participants finished Experiment II and twenty five showed stimulus equivalence. There was a significant interaction between the final evaluations and fictitious food names (p<0,001) in the equivalence group. The participants increased the final evaluations of the food trained with the happy face (capira), maintained almost the same evaluations of the food related with the neutral face (fulito) and considerably reduced the judgments of piteba, which was trained with the sad face.
8

Incidence d'une formation en intercompréhension sur l'acquisition de compétences en français et autres langues étrangères dans un contexte scolaire (lycée) / The effects of a training course in intercomprehension on the acquisition of skills in French and other foreign languages in a school context (secondary school)

Déprez, Sandrine 14 November 2014 (has links)
Depuis une vingtaine d'années, les chercheurs travaillent sur l'intercompréhension mais il n'y a pas à ce jour de véritable bilan de l'apport de cette nouvelle approche méthodologique sur les compétences langagières en langues étrangères des apprenants qui suivent ces formations. Cette thèse se propose d'analyser les effets d'une formation plurilingue en ligne sur l'acquisition de compétences langagières et, en particulier, en langue cible (français) pour des apprenants de lycée, de Barcelone. Pour pouvoir répondre à l'hypothèse selon laquelle la formation développerait les compétences des apprenants d'une part dans les langues de la formation mais également en français, la méthodologie adoptée a été la réalisation d'un protocole (quasi-) expérimental auprès de lycéens d'un établissement de Barcelone. Ce protocole a consisté à faire participer un groupe d'élèves à une session sur la plate-forme Galanet, de façon intégrée à leurs enseignements scolaires, ainsi qu'à la réalisation de tests pré- et post-formation. Un profil langagier a été complété par les sujets en amont de la formation. Chacun des tests présente le même type d'exercices, portant sur les mêmes compétences, et pour chacune des situations (initiale ou finale), il y a un test dont les supports sont en français et un autre dont les supports sont dans d'autres langues romanes (italien, portugais, roumain et occitan vivarois). Les compétences ciblées par les tests sont la cohérence/cohésion textuelle, la compréhension globale et fine, l'identification du degré de perception de l'interculturalité, la traduction/transposition, la segmentation et la reconnaissance/application d'un modèle discursif. Les données recueillies lors des tests ont fait l'objet d'analyses quantitatives et qualitatives, suivies de traitement statistiques quand il s'est agi d'établir, en particulier, des corrélations. En parallèle, le degré d'interactivité intercompréhensif (prenant en compte l'alternance des langues dans ce contexte bi-plurilingue) des messages de forum déposés lors de la formation plurilingue a été déterminé par le traitement semi-automatique du corpus de messages par la plate-forme Calico. C'est cette double analyse, basée sur des données concrètes expérientielles qui a permis de réaliser une étude de cas et de définir par l'étude longitudinale de leurs différents résultats si le fait de suivre de manière satisfaisante, en terme de participation, une formation en intercompréhension a une incidence positive sur l'acquisition des compétences évaluées par les tests, sur quelles compétences particulières et de quelle manière. / Investigators have been working on Intercomprehension for about twenty years. However, so far, there has not been any real assessment of the impact of this new methodological approach on the foreign language skills of students who have undergone such courses. This thesis aims to analyse the effects that a plurilingual course on line may have on the acquisition of language skills, especially the acquisition of a target language (French) by school students in Barcelona. In order to test the hypothesis that such a course may enhance students' skills both in the languages of the training course and in French, the chosen methodology implied the drafting of an (almost) experimental protocol designed for the students of a school in Barcelona. This protocol involved having a group of students participate in one of the training sessions set up on the Galanet platform, integrating it to their school teachings and including the drawing-up of different tests carried out before and after the course. Moreover, each student had to describe their language profile at the beginning of the training. Each test contains the same type of exercises, focusing on the same skills, and for each situation (either initial or final), there is one test on documents written in French and another on documents (written) in other romance languages (Italian, Portuguese, Romanian and Occitan - from the Vivarois region-). The skills' targets are as follows: textual coherence/cohesion, global and accurate comprehension, the identification of the degree of perception of interculturality, translation/reformulation, segmentation and the identification/ implementation of a speech model. All the data collected during the tests have been subject to both quantitative and qualitative analyses, and complemented by statistic processing, especially when correlations had to be made. At the same time the semi-automatic processing of the corpus of messages that was carried out using the Calico platform helped determine the degree of intercomprehensive interactivity (taking into account the code-switching in a bi/plurilingual context) of the messages posted on the forum during the plurilingual training course. This twofold analysis, based on concrete experiential data made it possible to conduct a case study and to determine, through the longitudinal study of their different results, if undergoing a training course in intercomprehension in a satisfactory way in terms of participation has a positive influence on the acquisition of the skills assessed by the tests, on which particular skill and how.
9

Using Trees to Capture Reticulate Evolution : Lateral Gene Transfers and Cancer Progression

Tofigh, Ali January 2009 (has links)
The historic relationship of species and genes are traditionally depicted using trees. However, not all evolutionary histories are adequately captured by bifurcating processes and an increasing amount of research is devoted towards using networks or network-like structures to capture evolutionary history. Lateral gene transfer (LGT) is a previously controversial mechanism responsible for non tree-like evolutionary histories, and is today accepted as a major force of evolution, particularly in the prokaryotic domain. In this thesis, we present models of gene evolution incorporating both LGTs and duplications, together with efficient computational methods for various inference problems. Specifically, we define a biologically sound combinatorial model for reconciliation of species and gene trees that facilitates simultaneous consideration of duplications and LGTs. We prove that finding most parsimonious reconciliations is NP-hard, but that the problem can be solved efficiently if reconciliations are not required to be acyclic—a condition that is satisfied when analyzing most real-world datasets. We also provide a polynomial-time algorithm for parametric tree reconciliation, a problem analogous to parametric sequence alignment, that enables us to study the entire space of optimal reconciliations under all possible cost schemes. Going beyond combinatorial models, we define the first probabilistic model of gene evolution incorporating a birth-death process generating duplications, LGTs, and losses, together with a relaxed molecular clock model of sequence evolution. Algorithms based on Markov chain Monte Carlo (MCMC) techniques, methods from numerical analysis, and dynamic programming are presented for various probability and parameter inference problems. Finally, we develop methods for analysis of cancer progression, a biological process with many similarities to the process of evolution. Cancer progresses by accumulation of harmful genetic aberrations whose patterns of emergence are graph-like. We develop a model of cancer progression based on trees, and mixtures thereof, that admits an efficient structural EM algorithm for finding Maximum Likelihood (ML) solutions from available cross-sectional data. / QC 20100812
10

Detecção dos genes integron, invA e spvC em Salmonella Enteritidis proveniente de material avícola e transferência horizontal do gene integron entre enterobactérias

Okamoto, Adriano Sakai [UNESP] 20 May 2009 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:33:26Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-05-20Bitstream added on 2014-06-13T18:45:08Z : No. of bitstreams: 1 okamoto_as_dr_botfmvz.pdf: 316486 bytes, checksum: 9da72cf8a36b7e04e7b42adc80fe9b71 (MD5) / Universidade Estadual Paulista (UNESP) / Neste trabalho foram analisadas 100 cepas de Salmonella Enteritidis (SE) isoladas de material avícola, visando à detecção dos genes de virulência spvC e invA e resistência a antimicrobianos integron classe 1. Comparando-se com a possível expressão dos fatores de virulência para sobrevivência em condições impróprias de temperatura, pH e concentração de nutrientes e o teste de inibição em placa, respectivamente. Também a capacidade de transferência horizontal do gene integron classe 1 foi avaliada em SE. Das cepas analisadas, duas apresentaram os genes spvC e invA, simultaneamente, com uma provável expressão destes sendo verificada no crescimento com pH 10,0 ou temperatura de 25ºC. Porém em relação à concentração de nutriente, ambas as cepas não cresceram na menor concentração (0,5%). Não houve relação direta entre a presença do gene integron classe 1 com a multiresistência de SE aos 14 antimicrobianos testados, já que 80% das cepas pesquisadas foram resistentes a até três antimicrobianos e não apresentaram o referido gene. Entretanto, a transferência horizontal desse gene e da resistência antimicrobiana foi realizada in vitro, de um Escherichia coli para uma Salmonella Enteritidis, demonstrando a capacidade de disseminação do gene presente em integron classe 1. / In this work, 100 strains of Salmonella Enteritidis (SE) isolated from avian material were studied, aiming to detect the genes of virulence spvC and invA, as well as the antimicrobial resistance type 1 integron genes using the polymerase chain reaction (PCR), comparing it with the possible expression of the virulence factors to survive under inappropriate conditions of temperature, pH and nutrient concentration, and the plaque inhibition assay, respectively. Capacity of horizontal transfer of type 1 0,integron gene was also evaluated in SE. Two of the analyzed strains showed spvC and InvA genes simultaneously, with a probable expression verified through growing in pH 10.0 or 25°C temperature. However, regarding to nutrient concentration, the aforementioned strains did not grow at the lowest concentration (0.5%). There was no direct relation between type 1 integron gene and the multiresistance of SE to the 14 tested antibiotics, because 80% of the strains did not showed the gen, but was resistant till three antibiotics. However, horizontal transfer of this gene was performed in vitro, showing the capacity of dissemination of the type 1 integron gene between bacteria.

Page generated in 0.038 seconds