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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.
581

Utveckling av en LC-MS-metod för analys av gamma-hydroxibutyrat, gamma-butyrolakton, 1,4-butandiol, amfetamin och metadon

Petersson, Birgitta January 2007 (has links)
<p>In this project a LC-MS-method for the analysis of gamma-hydroxybutyrate, gamma-butyrolactone, 1,4-butanediol, amphetamine and methadone was developed.</p><p>Initially, the efficiency of the ionisation of the analytes was evaluated with respect to the ionisation technique (ESI, APCI and APPI) and the composition of the mobile phase. In the next step a number of different columns was tested in order to find the one with the greatest potential for separation of the substances in question. Using the selected column, the separation was optimised by means of experimental design and the software The Unscrambler 7.8. The parameters studied were the flow rate, the column temperature and the mobile phase composition. The response variables were the resolution between the target compounds and the retention time of the last eluting compound.</p><p>These experiments showed that, in order to obtain the best ionisation, the mobile phase should consist of 5 mM formic acid in water and acetonitrile. ESI should be used in the positive mode for all analytes except gamma-hydroxybutyrate, for which the negative mode should be applied. The Hypercarb column exhibited superior retention of the analytes and was therefore selected for further optimisation. The dimensions of this column were 2.1 x 50 mm and the particle size 5 μm, connected to a 2.1 x 10 mm precolumn containing the same packing material. The optimum of the flow rate and the column temperature were 250 μl/min and 20 ºC respectively. For the separation of gamma-hydroxybutyrate, gamma-butyrolactone and 1,4-butanediol the mobile phase consisted of 100% water with 5 mM formic acid. Thereafter a gradient, up to 70% acetonitrile with 5 mM formic acid, was used in order to elute amphetamine and methadone. Efforts were also made to find an internal standard for the method. However, none of the compounds tested was found suitable.</p><p>In order to get the method usable for routine analysis, which is the goal, further work is required. A suitable internal standard needs to be added to the method and thereafter work remains with validation of the method.</p>
582

Évaluation comparative de stratégies visant à augmenter les interventions de courte durée en cessation tabagique auprès du personnel infirmier de milieux hospitaliers

Lepage, Mario 12 1900 (has links)
Introduction : Les résultats de recherches ont démontré que la cessation tabagique augmente là où des interventions professionnelles préventives sont appliquées avec constance. On rapporte qu’au Québec, 62 % des infirmières (toutes pratiques confondues) évaluent le statut tabagique de leurs clients et 38 % suggèrent la cessation tabagique. En milieu hospitalier, l’évaluation du statut tabagique diminue à 30 %. Or, le personnel infirmier hospitalier est présent dans les unités de soins 24 heures sur 24, ce qui laisse prévoir une influence potentielle non négligeable dans la décision des patients de cesser de fumer. Objectif : La présente recherche a pour objectif de comparer, avec un groupe contrôle, l’efficacité de stratégies (formation interactive, rappel, multiple) pour augmenter les interventions réalisées en cessation tabagique dans des unités de médecine et de chirurgie. Le choix de ces stratégies repose sur leur efficacité et leur potentiel d’implantation dans d’autres centres. Méthodologie : Un devis expérimental avec randomisation par groupe a été choisi. Le modèle factoriel permet d’évaluer l’effet de chacun des groupes expérimentaux en regard du groupe contrôle. Des mesures préstratégies et poststratégies (à 1 mois et à 3 mois) sont privilégiées. Plusieurs outils permettent de mesurer les effets des stratégies et ce, avec des sources diversifiées (personnel infirmier, patients, dossiers des patients, gestionnaires et responsables des centres d’abandon du tabac). Résultats : Au total, 156 infirmières et infirmières-auxiliaires ont répondu à des questionnaires au temps 1, 78 au temps 2 et 69 au temps 3. Parallèlement au personnel infirmier, 156 patients ont été rejoints au temps 1, 89 au temps 2 et 98 au temps 3. Les résultats démontrent que le personnel infirmier évalue le statut tabagique chez 35,7 % de la clientèle seulement et la motivation à cesser de fumer chez 17,6 % des patients. Au cours de notre recherche, peu d’interventions en cessation tabagique ont été réalisées dans les unités de médecine et de chirurgie; la présence de plusieurs obstacles de même qu’une perception d’inefficacité des interventions de la part du personnel infirmier semblent en être les causes. Les résultats de notre recherche ne nous a pas permis d’appuyer nos hypothèses. Cependant, des analyses complémentaires ont démontré que la stratégie de formation interactive a permis d’augmenter certaines pratiques cliniques à court terme et de diminuer la perception d’obstacles à l’intervention. Le rappel n’a pas fonctionné correctement et n’a pu être évalué. Conclusion : En considérant les résultats modestes des stratégies implantées, la formation interactive a eu un impact à très court terme sur les interventions courtes en cessation tabagique réalisées par le personnel infirmier d’unités de soins en médecine et en chirurgie. Les difficultés rencontrées lors de l’implantation des stratégies ont été expliquées, ce qui permettra une planification plus éclairée de futures recherches dans le domaine. / Introduction : Research results demonstrate a decrease in cigarette smoking when preventive professional interventions are routinely carried out. The Quebec recent literature reports that, nurses from different working areas assess their patient smoking habits 62 % of the time and recommend cessation in only 38 % of the situations. When this assessment is realized by hospital nurses, this percentage drops around 30 %. Knowing that nursing staff is present at the bedside 24 hours a day, a non-negligible influence of tobacco counselling by nurses is of potential interest for hospitalized patients. The objective of the present study is to compare, on medical and surgical units, the effectiveness of three strategies (interactive educational session, recall, and both together) to a control group, on the number of nursing interventions pertaining to cessation of cigarette smoking. Choice of those three strategies is based on reported effectiveness and transferability potential. Research design is experimental with group randomisation. Factorial model opens possibility to assess impact of each of the three strategies versus the control group. Pre and post strategy multi-measurements (at 1 and 3 months) are sought from nursing staff, patients, patient charts, management, nurses in charge of the centers for tobacco cessation. Results : Nursing staff completed questionnaires at time 1 (N = 156), at time 2 (N= 78), and at time 3 (N=69). Similarly, 156 patients were interviewed at time 1, 89 at time 2, and 98 at time 3. Results show that nursing staff assesses cigarette smoking habits for only 35,7 % of the patients, and their intent to stop smoking only 17,6 % of the time. Very few tobacco counselling interventions are carried out on medical and surgical units by nursing staff. Some barriers are identified, and nursing staff perceives a non-self-efficacy with regard to those interventions. Results do not allow confirmation of hypotheses. However, complementary statistical analyses show that the educational strategy increases the number of nursing interventions during a short period, and decreases perception of barriers to tobacco counselling. Impact of recall could not be assessed as it was not introduced as planned. Conclusion : Considering modest results from the strategies, the interactive educational sessions shows a short term effect on the nursing staff’s interventions,. The difficulties encountered during implementation of the strategies have been explained, which will be useful when planning future research in tobacco cessation.
583

Effects of a Dialogical Argumentation Instructional Model on Grade 10 Learners' Conception of Fermentation

Diwu, Christopher January 2010 (has links)
<p>The study catered for empirical and metaphysical dimensions of science and IKS. The study employed a quasi-experimental design as well as a qualitative research design. Two cohorts of students from a fictitiously named &ldquo / Culture Secondary School&rdquo / have been used in this study. The list of instruments for data collection were as follows: Conceptions of Fermentation (COF) questionnaire which was used to elicit learners&rsquo / pre- and post-test conceptions of fermentation with special reference to traditional beer or &ldquo / Umqombothi&rdquo / , an Attitudes to Science (ATS) questionnaire which was used to find out the learners&rsquo / worldviews, a Science Achievement Test (SAT) which was used to assess the learners&rsquo / generalised knowledge of fermentation, a classroom observation schedule as well as a focus group interview schedule to gather additional qualitative data. All the instruments were in English with all technical and difficult terms in both English and isiXhosa (the learners&rsquo / home language). Both groups were exposed to Science/IKS-based lessons. The only difference between the two groups was that, the experimental group (E group) was exposed to a Dialogical Argumentation Teaching Model (DAIM) and the comparison group (C group) to a traditional teaching approach. The data gatherred were both analyzed in terms of qualitative and quantitative descriptions.</p>
584

Effects of an argumentation-based instruction on grade 10 learners’ understanding of the causes of pollution at a river site

Magerman, Ruben Clive January 2011 (has links)
This study was based on the Science and Indigenous Knowledge Systems Project (SIKSP) at the School of Science and Mathematics Education, University of the Western Cape. The project seeks to enhance educators’ understanding of and ability to implement a Science-IKS curriculum (Ogunniyi, 2007) through using the theoretical framework of argumentation (Toulmin Argument Pattern) to the extent that learners would value the significance of both worldviews. This study sought to find the effects of an Argumentation-Based Instruction on grade 10 learners’ understanding of the causes of pollution at a river site. Since the integration of Science and IKS are envisaged by Curriculum 2005 (C2005), two theoretical argumentation constructs have been used namely, Toulmin’s (1958) Argumentation Pattern (TAP) and Ogunniyi’s (1995) Contiguity Argumentation Theory (CAT).
585

Metoder för informationsoptimering vid organisk syntes

Nordahl, Åke January 1990 (has links)
<p>Diss. (sammanfattning) Umeå : Umeå universitet, 1990, härtill 5 uppsatser.</p> / digitalisering@umu.se
586

Contributions to computer experiments and binary time series

Hung, Ying 19 May 2008 (has links)
This thesis consists of two parts. The first part focuses on design and analysis for computer experiments and the second part deals with binary time series and its application to kinetic studies in micropipette experiments. The first part of the thesis addresses three problems. The first problem is concerned with optimal design of computer experiments. Latin hypercube designs (LHDs) have been used extensively for computer experiments. A multi-objective optimization approach is proposed to find good LHDs by combining correlation and distance performance measures. Several examples are presented to show that the obtained designs are good in terms of both criteria. The second problem is related to the analysis of computer experiments. Kriging is the most popular method for approximating complex computer models. Here a modified kriging method is proposed, which has an unknown mean model. Therefore it is called blind kriging. The unknown mean model is identified from experimental data using a Bayesian variable selection technique. Many examples are presented which show remarkable improvement in prediction using blind kriging over ordinary kriging. The third problem is related to computer experiments with nested and branching factors. Design and analysis of experiments with branching and nested factors are challenging and have not received much attention in the literature. Motivated by a computer experiment in a machining process, we develop optimal LHDs and kriging methods that can accommodate branching and nested factors. Through the application of the proposed methods, optimal machining conditions and tool edge geometry are attained, which resulted in a remarkable improvement in the machining process. The second part of the thesis deals with binary time series analysis with application to cell adhesion frequency experiments. Motivated by the analysis of repeated adhesion tests, a binary time series model incorporating random effects is developed in this chapter. A goodness-of-fit statistic is introduced to assess the adequacy of distribution assumptions on the dependent binary data with random effects. Application of the proposed methodology to real data from a T-cell experiment reveals some interesting information. These results provide some quantitative evidence to the speculation that cells can have ¡§memory¡¨ in their adhesion behavior.
587

Apprendre un art ensemble : étude longitudinale d’enregistrements simultanés en électroencéphalographie lors de performances musicales / Learning and practising music together : a longitudinal EEG-hyperscanning study

Acquadro, Michaël 31 March 2016 (has links)
L’objectif de notre recherche est de comprendre les bases cérébrales de l’interaction sociale dans un contexte de performance musicale grâce à des outils issus des neurosciences (électroencéphalographie : EEG) et du traitement du signal. Ce manuscrit présente tout d’abord un état de l’art des études récentes dans le domaine de l’hyperscanning. Nous offrons une réflexion sur les prérequis et la méthodologie à adopter pour concevoir une expérience prédisposant à l’émergence d’une synchronisation neuronale. Nous explorons ensuite les processus cérébraux mis en jeu lors de la pratique de la musique au travers d’études réalisées en neurosciences. Par la suite nous présentons plusieurs méthodes permettant de calculer des indices de couplage cérébral sur les données récoltées lors d’expériences en hyperscanning. Nous y décrivons en particulier les méthodes de séparation de source conjointe (jBSS) dont l’avantage est de se rapprocher d’une réalité anatomique et physiologique, ainsi que de prendre en compte l’information inter-sujets lors de l’estimation des sources. Enfin, nous détaillons notre contribution au champ des neurosciences sociales sous la forme d’une expérience longitudinale en hyperscanning-EEG. Elle étudie l’interaction sociale de pianistes à quatre mains lors de l’apprentissage d’un morceau de musique sur une période de deux mois. Nous mettons en évidence qu’il existe une corrélation entre l’augmentation de la performance musicale au cours du temps, la synchronisation cérébrale et la qualité de la relation entre les musiciens. / The aim of our research is to understand the neural bases of social interaction in a musical performance context with tools from neuroscience (electroencephalography: EEG) and signal processing. This manuscript first presents a state of the art of recent studies in the field of hyperscanning. We introduce our recommendations on the prerequisites and methodology to design experiments facilitating the emergence of neuronal synchronization. We then explore the cerebral processes involved in the practice of music through studies in neuroscience of music. Subsequently we present several methods to calculate brain coupling on data collected during experiments in hyperscanning. We describe in particular the methods of joint blind source separation (jBSS) whose advantages are to approach anatomical and physiological reality, as well as taking into account inter-subject information when estimating sources. Finally, we detail our contribution to the field of social neuroscience with a longitudinal experience in hyperscanning-EEG. We studied social interaction from musicians playing four hands piano over a two-month period. We highlight a correlation between increased musical performance over time, cerebral synchronization and quality of the relationship between the pianists.
588

Etude de la dynamique des mécanismes de la répression catabolique : des modèles mathématiques aux données expérimentales / Study of the dynamics of catabolite repression : from mathematical models to experimental data

Zulkower, Valentin 03 March 2015 (has links)
La répression catabolique désigne un mode de régulation très répandu chez les bactéries, par lequel les enzymes nécessaires à l'import et la digestion de certaines sources carbonées sont réprimées en présence d'une source carbonée avantageuse, par exemple le glucose dans le cas de la bactérie E. coli. Nous proposons une approche mathématique et expérimentale pour séparer et évaluer l'importance des différents mécanismes de la répression catabolique. En particulier, nous montrons que l'AMP cyclique et l'état physiologique de la cellule jouent tous deux un rôle important dans la régulation de gènes sujets à la ré- pression catabolique. Nous présentons également des travaux méthodologiques réalisés dans le cadre de cette étude et contribuant à l'étude des réseaux de régulation génique en général. En particulier, nous étudions l'applicabilité de l'approximation quasi-stationnaire utilisée pour la réduction de modèles, et présentons des méthodes pour l'estimation robuste de taux de croissance, activité de promoteur, et concentration de protéines à partir de données bruitées provenant d'expériences avec gènes rapporteur. / Carbon Catabolite Repression (CCR) is a wide-spread mode of regulation in bacteria by which the enzymes necessary for the uptake and utilization of some carbon sources are repressed in presence of a preferred carbon source, e.g., glucose in the case of Escherichia coli . We propose a joint mathematical and experimental approach to separate and evaluate the importance of the different components of CCR. In particular, we show that both cyclic AMP and the global physiology of the cell play a major role in the regulation of the cAMP-dependent genes affected by CCR. We also present methodological improvements for the study of gene regulatory networks in general. In partic- ular, we examine the applicability of the Quasi-Steady-State-Approximation to reduce mathematical gene expression models, and provide robust meth- ods for the robust estimation of growth rate, promoter activity, and protein concentration from noisy kinetic reporter experiments.
589

Tamanho de parcela para experimentação com girassol / Size of the ground plot for experimentation with sunflower

Sousa, Roberto Pequeno de 29 November 2013 (has links)
Made available in DSpace on 2016-08-12T19:15:26Z (GMT). No. of bitstreams: 1 RobertoPS_TESE.pdf: 1647938 bytes, checksum: dc34992c335e50d26416144e8fb502c1 (MD5) Previous issue date: 2013-11-29 / This study aims to determine the appropriate size of field plots for field experimentation with sunflower. An experiment was conducted in randomized complete blocks design with 14 cultivars of sunflower and 10 replications. The field plots consisted of four rows of six-meter long rows, spaced 0.7 m and 0.3 m between plants, with a total area of 16.8 m2. The useful area of the plot (7.56 m2), consisting of the two central rows, was divided into 12 basic units, each one consisting of three plants in the row (0.63 m2). The production of sunflower grains obtained in basic units was grouped in order to form portions of seven kinds of five different predefined sizes. The appropriate size of the experimental plot was estimated by the following methods: a) Intraclass correlation coefficient b) Maximum modified curvature c) Segmented linear model with plateau and d) Hatheway (1961). Were also estimated the soil heterogeneity coefficient (b) and the detectable difference among treatments (d). There was a reduction in the coefficient of variation with increasing the size of the plot. The soil of the experiment showed high heterogeneity ( = 1.0585). They were estimated by the methods of the intraclass correlation coefficient, maximum modified curvature and segmented linear model with plateau, respectively, the optimal plot sizes corresponding to 2.52, 3.74 and 2.48 m2. The maximum modified curvature method presented estimate of the optimum plot size more appropriate, together with the detectable difference between means of cultivars to accurately assess the yield of sunflower grain. The plot of 3.74 m2 of useful area was considered appropriate to assess the yield of sunflower grains and it was smaller than the size generally used in researches with sunflower. Though the Hatheway method (1961), they were estimated several very aplicable plot sizes. Considering all the cultivars for the same difference to be detected among means of cultivars, the use of a portion of smaller size with the largest number of replicates required less experimental area than the larger plots with a fewer number of replications / O objetivo desse trabalho foi determinar o tamanho adequado de parcela para experimentação de campo com girassol. Foi realizado um experimento no delineamento em blocos completos casualizados com 14 cultivares de girassol e 10 repetições. As parcelas foram constituídas de quatro fileiras de seis metros de comprimento, espaçadas de 0,7 m e entre plantas de 0,3 m, com área total de 16,8 m2. A área útil da parcela (7,56 m2), composta das duas fileiras centrais, foi dividida em 12 unidades básicas, cada uma constituída de três plantas na fileira (0,63 m2). A produção de grãos do girassol obtida nas unidades básicas foi agrupada de modo a formar sete tipos de parcelas de cinco tamanhos diferentes pré-estabelecidos. O tamanho adequado da parcela experimental foi estimado por meio dos seguintes métodos: a) Coeficiente de correlação intraclasse; b) Máxima curvatura modificado; c) Modelo linear segmentado com platô e d) Hatheway (1961). Estimaram-se também o coeficiente de heterogeneidade do solo (b) e a diferença detectável entre tratamentos (d). Ocorreu redução do coeficiente de variação com o aumento do tamanho da parcela. O solo do experimento apresentou alta heterogeneidade ( = 1,0585). Foram estimados pelos métodos do coeficiente de correlação intraclasse, máxima curvatura modificado e modelo linear segmentado com platô, respectivamente, os tamanhos ótimos de parcela correspondentes a 2,52, 3,74 e 2,48 m2. O método da máxima curvatura modificado apresentou estimativa do tamanho ótimo da parcela mais adequado, aliado à diferença detectável entre médias de cultivares para avaliar com precisão o rendimento de grãos do girassol. Parcela 3,74 m2 de área útil foi considerada adequada para avaliação do rendimento de grãos do girassol e foi menor que o tamanho geralmente usado nas pesquisas com o girassol. Pelo método de Hatheway (1961) estimaram-se diversos tamanhos de parcelas, muitos aplicáveis. Considerando todas as cultivares, para uma mesma diferença a ser detectada entre médias de cultivares, a utilização de parcela de menor tamanho com maior número de repetições requereu menos área experimental do que parcelas maiores com menor número de repetições
590

Tamanho de parcela para experimentação com girassol / Size of the ground plot for experimentation with sunflower

Sousa, Roberto Pequeno de 29 November 2013 (has links)
Made available in DSpace on 2016-08-12T19:18:46Z (GMT). No. of bitstreams: 1 RobertoPS_TESE.pdf: 1647938 bytes, checksum: dc34992c335e50d26416144e8fb502c1 (MD5) Previous issue date: 2013-11-29 / This study aims to determine the appropriate size of field plots for field experimentation with sunflower. An experiment was conducted in randomized complete blocks design with 14 cultivars of sunflower and 10 replications. The field plots consisted of four rows of six-meter long rows, spaced 0.7 m and 0.3 m between plants, with a total area of 16.8 m2. The useful area of the plot (7.56 m2), consisting of the two central rows, was divided into 12 basic units, each one consisting of three plants in the row (0.63 m2). The production of sunflower grains obtained in basic units was grouped in order to form portions of seven kinds of five different predefined sizes. The appropriate size of the experimental plot was estimated by the following methods: a) Intraclass correlation coefficient b) Maximum modified curvature c) Segmented linear model with plateau and d) Hatheway (1961). Were also estimated the soil heterogeneity coefficient (b) and the detectable difference among treatments (d). There was a reduction in the coefficient of variation with increasing the size of the plot. The soil of the experiment showed high heterogeneity ( = 1.0585). They were estimated by the methods of the intraclass correlation coefficient, maximum modified curvature and segmented linear model with plateau, respectively, the optimal plot sizes corresponding to 2.52, 3.74 and 2.48 m2. The maximum modified curvature method presented estimate of the optimum plot size more appropriate, together with the detectable difference between means of cultivars to accurately assess the yield of sunflower grain. The plot of 3.74 m2 of useful area was considered appropriate to assess the yield of sunflower grains and it was smaller than the size generally used in researches with sunflower. Though the Hatheway method (1961), they were estimated several very aplicable plot sizes. Considering all the cultivars for the same difference to be detected among means of cultivars, the use of a portion of smaller size with the largest number of replicates required less experimental area than the larger plots with a fewer number of replications / O objetivo desse trabalho foi determinar o tamanho adequado de parcela para experimentação de campo com girassol. Foi realizado um experimento no delineamento em blocos completos casualizados com 14 cultivares de girassol e 10 repetições. As parcelas foram constituídas de quatro fileiras de seis metros de comprimento, espaçadas de 0,7 m e entre plantas de 0,3 m, com área total de 16,8 m2. A área útil da parcela (7,56 m2), composta das duas fileiras centrais, foi dividida em 12 unidades básicas, cada uma constituída de três plantas na fileira (0,63 m2). A produção de grãos do girassol obtida nas unidades básicas foi agrupada de modo a formar sete tipos de parcelas de cinco tamanhos diferentes pré-estabelecidos. O tamanho adequado da parcela experimental foi estimado por meio dos seguintes métodos: a) Coeficiente de correlação intraclasse; b) Máxima curvatura modificado; c) Modelo linear segmentado com platô e d) Hatheway (1961). Estimaram-se também o coeficiente de heterogeneidade do solo (b) e a diferença detectável entre tratamentos (d). Ocorreu redução do coeficiente de variação com o aumento do tamanho da parcela. O solo do experimento apresentou alta heterogeneidade ( = 1,0585). Foram estimados pelos métodos do coeficiente de correlação intraclasse, máxima curvatura modificado e modelo linear segmentado com platô, respectivamente, os tamanhos ótimos de parcela correspondentes a 2,52, 3,74 e 2,48 m2. O método da máxima curvatura modificado apresentou estimativa do tamanho ótimo da parcela mais adequado, aliado à diferença detectável entre médias de cultivares para avaliar com precisão o rendimento de grãos do girassol. Parcela 3,74 m2 de área útil foi considerada adequada para avaliação do rendimento de grãos do girassol e foi menor que o tamanho geralmente usado nas pesquisas com o girassol. Pelo método de Hatheway (1961) estimaram-se diversos tamanhos de parcelas, muitos aplicáveis. Considerando todas as cultivares, para uma mesma diferença a ser detectada entre médias de cultivares, a utilização de parcela de menor tamanho com maior número de repetições requereu menos área experimental do que parcelas maiores com menor número de repetições

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