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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.
11

Berechnung des Verhältnisses von Tryptophan zu den großen neutralen Aminosäuren im Tryptophandepletionstest

Beck, Matthias 17 January 2024 (has links)
Mit dem Tryptophandepletionstest kann kurzfristig die zentralnervöse Serotoninsynthese reduziert werden. Das TRP-LNAA-Ratio dient dabei zur Abschätzung der zentralnervösen Verfügbarkeit von TRP. In der Literatur besteht jedoch weder über die zu verwendenden LNAAs im Nenner des Ratios noch über die genaue Berechnungsmethode Einigkeit. Ziel dieser Arbeit war es, mithilfe von statistischen Methoden die verschiedenen LNAA-Kombinationen sowie die reguläre und die Km-normalisierte Berechnungsmethode zu vergleichen. Dafür wurden die LNAA-Konzentrationen verwendet, die in der dieser Arbeit zugrundeliegenden Studie erhoben wurden. Das Herausarbeiten von Unterschieden und Übereinstimmung, diente dem Zweck, eine Empfehlung für die Verwendung einer bestimmten LNAA-Kombination und einer Berechnungsmethode geben zu können. Die Ergebnisse dieser Arbeit zeigen, dass die Frage, welche Berechnungsmethode zur Bestimmung des TRP-LNAA-Ratios angewandt werden sollte, nicht trivial ist, da die Ratios beider Berechnungsmethoden nur eine sehr geringe Übereinstimmung zeigen. Die Tatsache, dass sich die Ratios unter Verwendung verschiedener LNAA-Kombinationen bei Anwendung der Km-normalisierten Berechnungsmethode kaum unterschieden, lässt die Km-normalisierte Berechnungsmethode gegenüber der regulären robuster erscheinen. Was die zu verwendende LNAA-Kombination anbelangt, wäre anzuraten, dass in zukünftigen Studien eine umfassende LNAA-Kombination auswählt wird, da das Ratio sich so stabiler gegen Ausreißer der einzelnen LNAAs darstellt.
12

Recherche d'indices de vie sur Mars :<br />détermination de signatures spécifiques de biominéraux et étude expérimentale de l'évolution de molécules organiques dans des conditions environnementales martiennes

Stalport, Fabien 30 November 2007 (has links) (PDF)
Les conditions indispensables à l'émergence de la vie terrestre ont surement été réunies sur Mars au début de son histoire. Une forme de vie martienne aurait alors pu apparaître et des indices de cette dernière auraient pu perdurer. Dans le cadre de la recherche de ces indices sur Mars, nos travaux s'articulent autour de deux cibles d'intérêt exobiologique : les biominéraux carbonatés et la matière organique. Dans la première partie, nous avons fait l'hypothèse que les températures de résistance thermique de carbonates biogéniques et abiotiques diffèrent du fait de leurs particularités intrinsèques. Nous les avons comparées via des analyses thermiques TG-ATD et nous avons constaté qu'un écart de 15°C sépare les domaines biologiques et abiotiques. Par conséquent nous avons ainsi accès à une signature biologique non ambiguë. Dans la seconde partie, nous avons testé la photostabilité et l'évolution d'acides carboxyliques et d'un biomarqueur bactérien, soumis au rayonnement ultraviolet simulé du soleil à la surface de Mars. Pour cela, nous avons développé une expérience de simulation en laboratoire : M.O.M.I.E. (Martian Organic Molecules Irradiation and Evolution). Nous avons observé que la plupart des molécules organiques sont détruites. Une seule, l'acide mélitique, produit un ou des composés organiques résistants. Nous avons ainsi accès aux taux de matière organique potentiellement présent à la surface/sous-surface de Mars. Les deux axes de recherche que nous avons suivis sont donc d'un grand intérêt exobiologique, car ils nous permettent de définir les stratégies expérimentales à mettre en oeuvre pour tenter de détecter in situ une activité biologique martienne.
13

Prvky xenofobie a veřejné mínění / Elements of xenophobia and public opinion

Marešová, Helena January 2013 (has links)
This tesis focuses on the issue of xenophobia and the meaning of public opinion about xenophobia by the template of secondary data analysis. The primary source for presented analysis was the research of The Center of Independent Public Opinion Research of the year 2011, which focused among other things on topic of foreigners in Czech republic. The main purpose of this tesis is to discover and to verify tendencies and attitudes of major czech public to the topic of foreigners living in our country. The tesis is from formaly standpoint separated into two basic parts. The theoretical part focuses on the very concept of xenophobia. It is the definition of this term. The focus is either concentrated to the theories of creation of xenophobia in the literature and theory. Between empirical and methodological part is a short chapter of operationalization of xenophobia concept. Fundamental part of the theoretical part is the chapter about the term foreigner itself where is defined how is this term used in all the tesis. Some space is push ahead with the description of foreigners living on the territory of Czech republic. Third chapter focuses on methodology. Shortly are mentioned basic premises of relations between xenophobia and other variables. To the reader are introduced primary data sets. This part is...
14

Concentração de argilominerais 2:1 em solos subtropicais / 2:1 clay minerals concentration in subtropical soils

Bertolazi, Vanessa Thoma 22 February 2013 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The 2:1 expandable clay minerals have high importance when present in soil, even in small amount, as in the case of soil with a high degree of secondary alteration. The study of these minerals is essential to understanding the physical and chemical behavior of soils, however, the techniques have not always permitted their suitable concentration, in order to facilitate their study. Therefore, this study aimed to analyze the concentration of phyllosilicates clay minerals with 2:1 structure through the technique of selective dissolution of oxides and kaolinite, aiming their study by X-ray diffraction and thermal analysis. The samples were collected in Rio Grande do Sul, in different weather conditions in profiles of Regosols (RRd and RRe), Ferralsol (LVd) and Vertisol (VEo). The clay fraction of A and B horizons of soil were separated and subjected to treatment with dithionite-citrate-bicarbonate and then with warm NaOH in 10 different concentrations, from 0.5 to 5 mol L-1. For mineralogical characterization we used the techniques of X-ray diffraction (XRD), thermogravimetry (TG) and differential thermal analysis (DTA). The results obtained by the analysis of X-ray diffraction showed that for most weathered soils as the Ferrasol, the NaOH solution does not contribute to the concentration of the 2:1 mineral. However, to the Vertisol the solution of NaOH 4.0 mol L-1 was more efficient in the concentration of minerals. To the Regossol RRd no concentration of NaOH solution was effective and to the RRe the concentration of 2.5 mol L-1 solution of NaOH was most suitable for concentrating the 2:1 clay. The extraction of kaolinite and gibbsite by NaOH solution was only partial for kaolinite. The thermal analysis showed predominance of kaolinite and gibbsite in relation to the 2:1 minerals in the samples free of oxides. The most effective treatment for the thermal analysis for 2:1 mineral concentration was NaOH 4 mol L-1 for samples LVd B, RRh A, RRe A and Veo A. The NaOH 3 mol L-1 treatment was more efficient for samples LVd A and VEo B. The relative concentration of 2:1 was higher in samples with dystrophic character. / Os argilominerais 2:1 expansíveis apresentam elevada importância quando presentes nos solos, mesmo em quantidade pequena, como no caso de solos com elevado grau de alteração secundária. O estudo destes minerais é fundamental para o entendimento do comportamento físico-químico dos solos, no entanto, as técnicas utilizadas nem sempre tem permitido a sua concentração adequada, de forma a facilitar o seu estudo. Por isso, este trabalho teve como objetivo analisar a concentração de argilominerais filossilicatos com estrutura 2:1 através da técnica de dissolução seletiva de óxidos e caulinita, visando o seu estudo por difratometria de raios-X e por análise térmica. As amostras analisadas foram coletadas no Rio Grande do Sul, em diferentes condições climáticas, em perfis de Neossolos (RRd e RRe), Latossolo (LVd) e Vertissolo (VEo). A fração argila dos horizontes A e B destes solos foram separadas e submetidas ao tratamento com ditionito-citrato-bicarbonato de sódio e posteriormente com NaOH a quente em 10 concentrações diferentes, a partir de 0,5 até 5 mol L-1. Para a caracterização mineralógica utilizou-se as técnicas de difração de raios-X (DRX), termogravimetria (TG) e análise térmica diferencial (ATD). Os resultados obtidos pelas análises de difratometria de raios-X mostraram que para solos mais intemperizados como o Latossolo a solução de NaOH não contribui para a concentrar os minerais 2:1. No entanto, para o Vertissolo a solução de NaOH 4,0 mol L-1 foi mais eficiente na concentração desses minerais. Os Neossolos apresentaram comportamento distinto, sendo que para o RRd nenhuma concentração da solução de NaOH foi eficiente e para o RRe a concentração de 2,5 mol L-1 da solução de NaOH foi a mais adequada para a concentração dos argilominerais 2:1. A extração da caulinita e gibbsita através da solução de NaOH foi apenas parcial para a caulinita, observou-se a permanência deste mineral em boa parte das concentrações. As análises térmicas mostraram predominância de caulinita em relação à gibbsita e minerais 2:1 nas amostras desferrificadas. O tratamento mais eficiente, pela análise térmica, para concentração de minerais 2:1 foi o NaOH 4 mol L-1 para as amostras LVd B, RRh A, RRe A e VEo A e o tratamento NaOH 3 mol L-1 para as amostras LVd A e VEo B. A concentração relativa de 2:1 foi maior nas amostras com caráter distrófico.
15

DEVELOPMENT OF A FORCE SENSING INSOLE TO QUANTIFY IMPACT LOADING TO THE FOOT IN VARIOUS POSTURES / A FORCE SENSING INSOLE TO QUANTIFY IMPACT LOADING TO THE FOOT

Van Tuyl, John T. January 2014 (has links)
Lower leg injuries commonly occur in both automobile accidents and underbody explosive blasts, which can be experienced in war by mounted soldiers. These injuries are associated with high morbidity. Accurate methods to predict these injuries, especially in the foot and ankle, must be developed to facilitate the testing and improvement of vehicle safety systems. Anthropomorphic Test Devices (ATDs) are one of the tools used to assess injury risk. These mimic the behavior of the human body in a crash while recording data from sensors in the ATD. Injury criteria for the lower leg have been developed with testing of the leg in a neutral posture, but initial posture may affect the likelihood of lower leg injury. In this thesis, the influence of initial posture on key injury assessment criteria used in crash testing with ATDs was examined. It was determined that these criteria are influenced by ATD leg posture, but further work is necessary to determine if the changes in outcome correspond to altered injury risk in humans when the ankle is in the same postures. In order to better quantify the forces acting on various areas of the foot and correlate those with injury, allowing for development of new criteria, a purpose built force sensor was created. An array of these sensors was incorporated into a boot and used to instrument an ATD leg during impact testing. The sensors provided useful information regarding the force distribution across the sole of the foot during an impact. A numerical simulation of the active material in the sensor was also created to better understand the effect of shear loading on the sensor. This work furthers the understanding of lower leg injury prediction and develops a tool which may be useful in developing accurate injury criteria for the foot and lower leg. / Thesis / Master of Applied Science (MASc) / This work investigates how the posture of the lower leg of a crash test dummy can influence the interpretation of crash test results. A tool was created to measure forces acting on the foot during testing. The force measurement uses a material which changes resistance when it is compressed.
16

The Selective Effect of Estrogen Receptor Alpha and Beta on Activity and Social Behavior in Neonatal Male Prairie Voles

Zushin, Peter-James H. 05 October 2009 (has links)
No description available.
17

Orkestrering för ett matematiskt lärande : Praxeologier i matematikundervisning / Orchestration for mathematical learning : Praxeologies in mathematics education

Herbut, Sebastian, Sandström, Nicklas January 2023 (has links)
I den här studien åskådliggörs tre skilda perspektiv på hur undervisning kan planeras ochorganiseras i relation till matematikinnehåll, struktur och yttre resurser. Tidigare forskningbelyser hur lärarens arbete kring planering i stor utsträckning kan vara avgörande förelevernas lärande i matematik. Vidare belyser studien vikten av reflektioner och planering föratt medvetet uppmärksamma eleverna på de kritiska momentana inom matematiken.Skolinspektionens (2020) rapport benämner hur allt färre lärare reflekterar kring sin egenundervisning i syfte att utveckla lärandet. Resultaten pekar på ett liknande fenomen närdeltagarna talar om reflektionens roll för undervisningen. Vidare synliggör studienläromedlets roll för både planeringsarbetet, genomförandet av undervisningen samtreflektionen.
18

Comparison of Q3s Anthropomorphic Test Device Biomechanical Responses to Pediatric Volunteers

Ita, Meagan Eleanor 02 September 2014 (has links)
No description available.
19

Development of Innovative 6a Omega Head Instrumentation Fixture for the Hybrid III 50th Percentile Male

Croyle, Colleen M. 07 September 2017 (has links)
No description available.
20

Human Thoracic Response to Impact: Chestband Effects, the Strain-Deflection Relationship, and Small Females in Side Impact Crashes

Shurtz, Benjamin K. 07 December 2017 (has links)
No description available.

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