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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.
31

Ensinar em reconstrução : conceitos e concepções de ensino de professoras dos anos iniciais do ensino fundamental em uma formação continuada de matemática a distância

Serres, Fabiana Fattore January 2017 (has links)
Para responder a questão de pesquisa desta tese: “Como ocorre o processo de reconstrução da concepção de ensino e de conceitos de Matemática em uma formação continuada a distância para professoras dos Anos Iniciais do Ensino Fundamental?”, este trabalho traz a análise de uma formação construída em um modelo de EaDonline de “muitos-para-muitos” com proposta de forte interação entre aluno-aluno e aluno-professor. Apoiados na teoria de Jean Piaget sobre a equilibração das estruturas, em relação às suas noções de espaço e forma, investigamos os registros de professoras em exercício, buscando indícios de reconstruções de conceitos matemáticos e de suas concepções pedagógicas. Os resultados obtidos nesta pesquisa apontam para a importância do investimento em ações de formação continuada para professores, especialmente para professores dos Anos Iniciais. Todos os conteúdos de matemática são importantes, mas, em especial é preciso abordar geometria, uma vez que estas professoras tem pouco ou nenhum contato com geometria tanto na escola básica como em sua graduação. / To answer the research question of this thesis: "How does the process of reconstruction of the conception of teaching and concepts of Mathematics in a continuous distance formation for teachers of the Initial Years of Elementary School?", This work brings the analysis of a formation built on a "many-to-many" EaDonline model with a strong proposal between student-student and student-teacher. Based on Jean Piaget's theory on the balancing of structures, in relation to their notions of space and form, we investigate the records of practicing teachers, searching for signs of reconstruction of mathematical concepts and their pedagogical conceptions. The results obtained in this research point to the importance of investing in continuing education actions for teachers, especially for Early Years teachers. All mathematical content is important, but in particular, geometry must be addressed, since these teachers have little or no contact with geometry in both elementary school and graduate school.
32

Avaliação das cristas oclusais de pré-molar antes e depois de tratamento dental em equinos da raça mangalarga marchador

Dietrich, Lizzie de Oliveira January 2018 (has links)
As cristas oclusais dos equinos surgiram no processo evolucionário da espécie para aumentar sua capacidade de pastoreio e de trituração. A diferença de dureza dos tecidos dentários (cemento, dentina e esmalte) e a pressão mastigatória na superfície oclusal do dente hipsodonte promovem o aparecimento das cristas oclusais afiadas. O tratamento dentário visando o desgaste das desordens oclusais representa a melhor forma de evitar prejuízos digestórios e biomecânicos em cavalos de esporte. O objetivo deste estudo foi mensurar e comparar a altura das cristas oclusais (ACO) do quarto pré-molar antes e após o tratamento de odontoplastia. Foram avaliadas 10 éguas da raça Mangalarga Marchador, na faixa etária de 5 a 12 anos, sob manejo extensivo, mensurando a altura da crista oclusal (ACO) do Triadan 408 por meio de modelos de gesso antes, imediatamente após, 15 dias e 50 dias após a odontoplastia. Logo após o procedimento a ACO era apenas 21,9% da ACO de antes do equilíbrio oclusal; contudo em 15 dias da odontoplastia, 65,9% da ACO já estava reestabelecida, e em 50 dias após o procedimento, 80,3% da ACO. As ACOs dos pontos bucais ressurgiram antes das ACOs linguais, sugerindo uma maior pressão mastigatória destes pontos bucais. A pressão mastigatória e a diferença de dureza dos tecidos dentários oclusais favorece o rápido ressurgimento das cristas trituratórias. Conclui-se que aos 15 dias do tratamento dental, o equino já possui novamente capacidade trituratória do alimento, visto que ACO apresenta-se aparente na superfície oclusal do molar que sofreu odontoplastia. / The occlusal ridges of the equines appeared in the evolutionary process of the species to increase its capacity of grazing and trituration. The difference in hardness of dental tissues (cementum, dentin and enamel) and masticatory pressure on the occlusal surface of the hypsodont tooth promote the appearance of sharp occlusal ridges. Dental treatment aimed at the wearing down of occlusal disorders represents the best way to avoid digestive and biomechanical damages in sport horses, avoid severe fractures in molars. The aim of this study was to measure and compare the height of the occlusal ridges (HOR) of the fourth pre-molar before and after odontoplasty. Ten Mangalarga Marchador´s mares, aged 5 to 12 years, under extensive management, were evaluated by measuring the height of occlusal ridges (HOR) in Triadan 408, using plaster models before, immediately after, 15 days and 50 days after odontoplasty. Immediately after the procedure the HOR was only 21.9% of the HOR before the occlusal equilibration; however in 15 days of odontoplasty, 65.9% of HOR was already reestablished, and in 50 days after the procedure, 80.3% of HOR was. HOR in the buccal side resurfaced before the lingual HORs, suggesting the greater masticatory pressure of these buccal points. The masticatory pressure and the hardness difference of the occlusal dental tissues favors the rapid resurgence of the trituration ridges. It is concluded that 15 days after the dental treatment, the horse already has the triturational capacity of the food, since ACO is apparent on the occlusal surface of molar suffered in odontoplasty.
33

Uplatnění statistických metod při posuzování finanční výkonnosti podniku / Use of Statistical Methods for Assessment of the Financial Company Performance

Dvořák, Václav January 2013 (has links)
This thesis deals with the use of statistical methods in practice. From the field of statistics is the work of regression analysis and time series analysis, which brought to a critical assessment of the financial situation of the company HELIX Liberec, s.r.o. The work is divided into theoretical and practical parts. The theoretical part focuses on explanations of important terms of statistical and financial analyzes that are subsequently applied in the practical part. Finally, the practical part are assessed and proposals to improve the economic situation.
34

Le pilotage des interfaces organisationnelles : Contribution à l’équilibration des processus d’intégration-différenciation des organisations / Piloting of the Organizational Interfaces : Contribution to the Equilibration of the integration-differentiation processes of organizations

Seghier, Sofian 13 February 2012 (has links)
L’interface organisationnelle demeure un objet peu étudié. La recherche se propose de l’explorer et d’en comprendre les dynamiques.La première partie explicite les fondements de la recherche. Après avoir défini l’interface, elle fait apparaître que l’instabilité des interfaces résulte de déséquilibres dans les processus d’intégration-différenciation. Pour mesurer ces phénomènes, la méthodologie fait appel à deux méthodes : l’élaboration et l’analyse d’une base de verbatim, et une recherche-intervention.La deuxième partie est consacrée aux déterminants de l’objet. Elle précise les propriétés et les activités de l’interface, et en propose une modélisation. Une analyse croisée de 14 interfaces est ensuite exposée ; trois déterminants de la régulation à l’interface sont identifiés : le degré d’incertitude, la fréquence des interactions et la répartition du pouvoir. Sur ces bases, une typologie des interfaces est proposée : stratégiques, politiques, de coordination, et sociales.La troisième partie approfondit la recherche par l’observation in vivo et la transformation des interfaces. Elle met en évidence leurs coûts de fonctionnement, le rôle fondamental de leur finalisation, et montre que les processus d’intégration et de différenciation posent la question de leur qualité, en plus de celle de leur intensité. L’hypothèse selon laquelle le pilotage des interfaces organisationnelles améliore l’équilibration de l’intégration-différenciation est discutée puis expérimentée. À partir des premiers résultats d’expérimentation, la recherche identifie des leviers de pilotage des interfaces et formule des implications managériales. / The organizational interface remains a little studied object. The research suggests investigating it and understanding the dynamics.The first part clarifies the foundations of the research. Having defined the interface, il creates that the instability of the interfaces results from imbalance in the processes of integration-differentiation. To measure these phenomena, the methodology appeals to two methods: the elaboration and the analysis of a base of verbatim, and a research-intervention.The second part is dedicated to the determiners of the object. She specifies the properties and the activities of the interface, and proposes a modelling. A crossed analysis of 14 interfaces is then explained; three determiners of the regulation in the interface are identified: the degree of uncertainty, the frequency of the interactions and the distribution of the power. On these bases, a typology of the interfaces is proposed: strategic, political, of coordination, and social.The third part deepens the research by the in vivo observation and the transformation of the interfaces. It brings to light their costs of functioning, the fundamental role of their finalization, and shows that the processes of integration and differentiation ask the question of their quality, besides that of their intensity. The hypothesis according to which the piloting of the organizational interfaces improves the équilibration of the integration-differentiation is discussed then experimented. From the first results of experiment, the research identifies levers of piloting of the interfaces and formula of the managerial implications.
35

台北市立國民中小學學生邏輯概念發展之橫斷研究 / Development of Logical Thinking : From First to Nineth Grade

邱素真, Chiu,Su-chen Unknown Date (has links)
本研究採用分層叢集抽樣,從台北市十二行政區中,按比例抽出36所學校。受試者含1-9年級學生合計5475人,有效樣本4917人達89.8%。自編測驗信度、效度考驗:α係數達.80,效標關連效度在.21到.70之間,與智力測驗之相關在各年級均達.01顯著水準,專家效度良好。研究發現包括二部份: 一、邏輯概念之發展:有關台北市立國民中小學學生邏輯概念發展狀況研究結果如次 (1) 形式運思階段之前,兒童可以解答部份的命題邏輯問題。 (2) 具體內容的MP規則和常見的遞移性關係的遞移推理,分別在國小一年級、及國小四年級已達到發展高原。 (3) 從具體運思到形式運思階段,並沒有發現階段性跳躍的成長現象,邏輯概念發展大致上是向上發展的型態。 (4) 二元運算系統在8,9年級(14、15歲左右)--也就是皮亞傑所指的形式運思階段達到平衡的時期,只能做大約18%?32%的題目,沒有證據顯示大部份的受試者,已經完成了具有「群與格」特徵的命題邏輯結構。本研究的假設一、假設二均未獲得支持。皮亞傑理論對學生的邏輯概念發展有低估和高估的現象。一方面低估了國小中低年級兒童在簡單邏輯規則的發展,另一方面高估了青少年在困難的邏輯規則上所能達到的成就。 二、邏輯概念與數學之相關性:在邏輯與數學的相關性研究方面獲得以下結論: (1) 邏輯成績與數學成績的相關在各年級學生中,均達.0001顯著水準。大部份年級數學成績與智力的相關,大於數學成績與邏輯概念的相關。 (2) 年級對邏輯概念的影響效果顯著,當控制智力高低及數學成就好壞二個因素之後,邏輯概念隨年級而增進。 (3) 數學成就對邏輯概念的影響效果顯著,對各年級學生而言,高數學成就組學生的邏輯概念比其他二組好。但數學成就中等和低等的二組受試者之間,當智力的百分等級在35?56之間時,邏輯概念沒有差異。 (4) 變異數分析顯示,以年級、數學成就與智力的線性模式,可以解釋邏輯概念所有變異量中的63%。共變異數分析顯示,排除智力的影響之後,年級、數學成就仍是可以解釋邏輯概念所有變異量中的63%,與變異數分析結果一致。
36

A study of atom and radical kinetics

Hanning-Lee, Mark Adrian January 1990 (has links)
This thesis describes the measurement of rate constants for gas phase reactions as a function of temperature (285 ≤ T/K ≤ 850) and pressure (48 ≤ P/Torr ≤ 700). One or both reactants was monitored directly in real time, using time–resolved resonance fluorescence (for atoms) and u.v. absorption (for radicals). Reactants were produced by exciplex laser flash photolysis. The technique was used to measure rate constants to high precision for the following reactions under the stated conditions: • H+O2+He->HO2+He and H+O2−→OH+O, for 800 ≤ T/K ≤ 850 and 100 ≤ P/Torr ≤ 259. A time–resolved study was performed at conditions close to criticality in the H2–O2 system. The competition between the two reactions affected the behaviour of the system after photolysis, and the rate constants were inferred from this behaviour. • H+C2H4+He<-->C2H5+He (T = 800 K, 97 ≤ P/Torr ≤ 600). The reactions were well into the fall–off region at all conditions studied. At 800 K, the system was studied under equilibrating conditions. The study provided values of the forward and reverse rate constants at high temperatures and enabled a test of a new theory of reversible unimolecular reactions. The controversial standard enthalpy of formation of ethyl, DH0f,298 (C2H5), was determined to be 120.2±0.8 kJ mol−1. Master Equation calculations showed that reversible and irreversible treatments of an equilibrating system should yield the same value for both thermal rate constants. • H+C3H5+He->C3H6+He (T = 291 K, 98 ≤ P/Torr ≤ 600) and O+C3H5 −→ products (286 ≤ T/K ≤ 500, 48 ≤ P/Torr ≤ 348). Both reactions were pressure–independent, and the latter was also independent of temperature with a value of (2.0±0.2) ×10−10 cm3 molecule−1 s−1. • H+C2H2+He<-->C2H3+He (298 ≤ T/K ≤ 845, 50 ≤ P/Torr ≤ 600). At 845 K, both reactions were in the fall–off region; rate constants were used to determine the standard enthalpy of formation of vinyl, ¢H0f,298 (C2H3), as 293±7 kJ mol−1. The value of this quantity has until recently been very controversial. • H+CH4 <--> CH3+H2. The standard enthalpy of formation of methyl, DH0 f,298 (CH3), was determined by re–analysing existing kinetic data at T = 825 K and 875 K. A value of 144.7±1.1 kJ mol−1 was determined. Preliminary models were examined to describe the loss of reactants from the observation region by diffusion and pump–out. Such models, including diffusion and drift, should prove useful in describing the loss of reactive species in many slow–flow systems, enabling more accurate rate constants to be determined.
37

Impact of Li non-stoichiometry on the performance of acoustic devices on LiTaO3 and LiNbO3 single crystals / Effet de nonstoechiométrie en Li sur la performance des dispositifs à ondes élastiques à base de monocristaux de LiTaO3 et LiNbO3

Gonzalez, Minerva 19 July 2016 (has links)
Les technologies de filtres, résonateurs, oscillateurs et capteurs sont des éléments essentiels dans lesindustries des télécommunications, automobile, militaire, médical, etc. Les monocristaux de LiTaO3 (LT) etLiNbO3 (LN) sont les matériaux les plus utilisés pour la fabrication de filtres de radiofréquence à ondesélastiques des téléphones portables, car ils possèdent un facteur de couplage électromécanique (K2) élevé.Cependant, ils présentent une problématique liée à la variation de la fréquence de fonctionnement avec latempérature (CTF), dont la valeur est environ de -40 à -95 ppm/°C. D’autre part, il a été démontré dans lalittérature que les propriétés de LT et LN changent avec la non-stoechiométrie du Li.L’objectif de cette thèse a été l’étude de l’effet de la concentration en Li2O sur la performance desdispositifs acoustiques à ondes élastiques de surface, utilisant comme substrat piézoélectrique desmonocristaux de LT coupe YXl/42 (42 RY-LT) et LN coupe YXl/128 (128 RY-LT). Cette étude vise àl’amélioration du CTF sans la dégradation d’autres propriétés (K2 et pertes d’insertion) dans le cas du 42 RYLTet la stabilité de dispositifs utilisés à haute densité de puissance dans le cas du 128 RY-LN. Tout d’abord,nous avons préparé des monocristaux de LT et LN avec différente concentration en Li2O :48.5-50 mol%, enutilisant la méthode d’équilibration par transport en phase vapeur (VTE). Ensuite, nous avons fabriqué etcaractérisé des dispositifs à ondes élastiques de volume et de surface à base de LT et LN, traités par VTE, afind’étudier l’effet de la non-stoechiométrie de Li et l’effet des domaines ferroélectriques sur leur performance. / The filter technologies, resonators, oscillators and sensors are essential elements fortelecommunications, automotive, military, medical industries. The most of radio frequency surface acousticwave (RF-SAW) filters, present in mobile phones, are based in LiNbO3 (LN) and LiTaO3 (LT) single crystalsbecause they have high electromechanical coupling factor (K2). However, these materials have a problemrelated to the variation of the operating frequency with temperature (TCF), whose value is about -40 to -95ppm / ° C. On the other hand, it has been previously shown in the literature that the physical and structuralproperties of LT and LN change with Li non-stoichiometry, including elastic properties.The aim of this work was the investigation of the impact of Li2O concentration on the performance ofSAW devices based on YXl/42 (42 RY-LT) and YXl/128 (128 RY-LN) single crystals. In the case of 42 RY-LT,we focused in the reduction of TCF without the degradation of other properties (K2 and insertion losses) andin the case of 128 RY-LN crystals we focused in the stability of devices at high power densities. First, singlecrystals of LT and LN with different Li2O concentration: 48.5-50 ml% were prepared, by using the VaporTransport Equilibration (VTE) method. Afterwards, SAW and bulk acoustic wave (BAW) devices based on LTand LN VTE treated crystals, were fabricated and characterized, in order to study the effect of Li nonstoichiometryand the effect of ferroelectric domains on the performance of devices.
38

Investigation of the emergence of thermodynamic behavior in closed quantum systems and its relation to standard stochastic descriptions

Schmidtke, Daniel 20 August 2018 (has links)
Our everyday experiences teach us that any imbalance like temperature gradients, non-uniform particle-densities etc. will approach some equilibrium state if not subjected to any external force. Phenomenological descriptions of these empirical findings reach back to the 19th century where Fourier and Fick presented descriptions of relaxation for macroscopic systems by stochastic approaches. However, one of the main goals of thermodynamics remained the derivation of these phenomenological description from basic microscopic principles. This task has gained much attraction since the foundation of quantum mechanics about 100 years ago. However, up to now no such conclusive derivation is presented. In this dissertation we will investigate whether closed quantum systems may show equilibration, and if so, to what extend such dynamics are in accordance with standard thermodynamic behavior as described by stochastic approaches. To this end we consider i.a. Markovian dynamics, Fokker-Planck and diffusion equations. Furthermore, we consider fluctuation theorems as given e.g. by the Jarzynski relation beyond strict Gibbsian initial states. After all we find indeed good agreement for selected quantum systems.
39

Détermination des coefficients de partage sang:air, urine:air et plasma:air de composés organiques volatils d’origine microbienne

Berkane, Wissam 12 1900 (has links)
Résumé: De nombreuses études ont établi que l’exposition aux moisissures intérieures peut être nuisible à la santé. Dans une récente étude, 21 composés organiques volatils microbiens (COVM) ont été sélectionnés comme biomarqueurs potentiels de l’exposition aux moisissures intérieures. L’objectif du projet était de déterminer les coefficients de partage (CP) sang:air, urine:air, plasma:air et eau:air pour ces composés, paramètres utilisés dans la prédiction de la toxicocinétique des xénobiotiques. Pour y parvenir, la méthode de flacons à l’équilibre a été utilisée. Les COVM (1.57-2.01 µg) injectés dans des flacons (20 ml) hermétiquement scellés contenant soit 0.5 ml de matrice (flacons test) ou simplement de l’air (flacons références) ont été incubés 60 min à 37⁰ C sous agitation continue. La quantification des COVM dans l’espace de tête des flacons (test et références) a été ensuite faite par chromatographie en phase gazeuse couplée à la spectrométrie de masse (GC-MS/MS). Les CP de 19 COVM variaient entre 78 et 4721 pour sang:air, 14 et 3586 pour urine:air, 64 et 5604 pour plasma:air et 16 et 2210 pour eau:air. Les CP eau:air étaient étroitement liés aux CP urine:air pour 17 COVM (R2 = 0,97, pente =1,001) suggérant que la valeur de CP eau:air (lorsqu’inférieur à103) peut être un substitut au CP urine:air. L’étude des ratios sang:urine indique que six COVM seraient nettement plus concentrés dans le sang, matrice de choix pour ces composés. Les données générées par cette étude faciliteront le développement de modèles pharmacocinétiques de COVM et le paramétrage de leurs prélèvements en tant que biomarqueurs de l’exposition aux moisissures intérieures. / Abstract: Numerous studies have established that exposure to indoor molds can be harmful to health. In a recent study, 21 microbial volatile organic compounds (mVOCs) were selected as potential biomarkers of indoor mold exposure. The objective of the project was to determine the blood:air, urine:air, plasma:air, and water:air partition coefficients (PCs) for these compounds, parameters used in predicting the toxicokinetics of xenobiotics. To achieve this, the vial-equilibration method was used. mVOCs (1.57-2.01 µg) were injected into hermetically sealed vials (20 ml) containing either 0.5 ml of matrix (test vials) or simply air (reference vials) and were incubated for 60 min at 37 ⁰C under continuous agitation. Quantification of mVOCs in the headspace of the vials (test and reference) was then performed by gas chromatography mass spectrometry (GC-MS/MS). The PCs of 19 mVOCs ranged from 78 and 4721 for blood:air, 14 and 3586 for urine:air, 64 and 5604 for plasma:air, and 16 and 2210 for water:air. Water:air PCs were closely related to urine:air PCs for 17 mVOCs (R2 = 0.97, slope =1.001) suggesting that the water:air PC value (when less than 103) may be a surrogate for the urine:air PC. The blood:urine ratio study indicates that six mVOCs would be significantly more concentrated in blood, the matrix of choice for these compounds. The data generated from this study will facilitate the development of pharmacokinetic models of mVOCs and the parameterization of their sampling as biomarkers of indoor mold exposure.
40

Strange Metal Behavior of the Hall Angle in Twisted Bilayer Graphene & Black Phosphorus Quantum Point Contact Devices

Tuchfeld, Zachary Jared January 2021 (has links)
No description available.

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