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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.
331

Lokální adaptace přírodních populací Arabidopsis arenosa k hadci. / Local adaptation of natural population of Arabidopsis arenosa to serpentine soil

Lamotte, Timothée January 2021 (has links)
Arabidopsis arenosa represents a promising model for studying the mechanisms underlying the adaptation to serpentine soil. Genetic basis of serpentine adaptation is still poorly known and A. arenosa possesses many advantages as a tool to complete that knowledge. The first step of this study was to reveal the presence of a local adaptation to serpentine soil in a population of A. arenosa. To do so, I used the data from a reciprocal transplant experiment realized between a Czech pair of serpentine - non-serpentine populations and I explored the phenotypes associated with the adaptation. Subsequently, I produced the F2 hybrids coming from crosses between serpentine - non-serpentine parents and I studied the expression of fitness traits in F2 plants growing in serpentine in order to estimate the number of loci underlying the adaptation which I compared with other studies. I confirmed the presence of a local adaptation, with the population of serpentine origin performing better than the non-serpentine population in the serpentine substrate of origin, associated with accumulation of heavy metals in the leaves. Analyses of the soil composition revealed differences in heavy metals and nutrients contents, Ca/Mg ratio and pH between the two localities. Those results fitted with the function of the candidate...
332

Förskollärares syn på barns erfarande vid kemiexperiment : En kvalitativ intervjustudie i förskolan / Preschool Teacher's Views on Children's Experiences in Chemistry Experiments : A qualitative Interview Study in Preschool

Köhlström, Ann-Kristine January 2022 (has links)
This study has investigated how preschool teachers perceive the children's experience, actions and assimilation of information through chemistry experiments. Interviews were conducted with six teachers. The informants were given the same basic questions based on an interview guide with spontaneous follow-up questions mixed in. The interviews were recorded and transcribed. The transcribed data was then analyzed using a framework that has been adapted for the study where data has been divided, categorized and analyzed to identify consistent themes. The results show that teachers perceive that the children have varying prior knowledge, which affects the ability to understand chemistry experiments. Those children who do not have as much prior knowledge are considered to need to find more basic critical aspects of the phenomenon first. In the teachers' experiences of how children act in an experiment, the children are considered to have a high level of interest and the interest increases when the children see clear results. It is important that the children participate physically. Regarding the assimilation of the meaning of the chemistry experiments, documentation and reflection are highlighted as key factors. The teachers considered it important to have open-ended questions to encourage the children's own reflections. Recommendation for the organization is to think about using the right concepts in the work with chemistry, to continue to document and reflect on the various activities together with the children and to take advantage of and follow the children's interest. / Denna studie har undersökt hur förskollärare uppfattar barnens erfarande, agerande och tillgodogörande av information i samband med kemiexperiment. Semi-strukturerade intervjuer har genomförts med sex förskollärare. Intervjuerna har spelats in och sedan transkriberats. Insamlade data har analyserats med hjälp av Maguire och Delahunts (2017) ramverk som anpassats för studien där data delats upp, kategoriserats och analyserats för att identifiera genomgående teman. Resultatet visar att förskollärare uppfattar att barnen har varierande förkunskaper, vilket påverkar förmågan att förstå kemiexperimenten som utförs. De barn som inte har lika mycket förkunskaper anses behöva hitta mer grundläggande kritiska aspekter av fenomenet först. I förskollärarnas upplevelser kring hur barn agerar i ett experiment anses barnen ha högt intresse och intresset ökar när barnen ser tydliga resultat. Förskollärarna upplever att det är viktigt att barnen får delta fysiskt. Gällande tillgodogörande av meningen med kemiexperimenten lyfts dokumentation och reflektion fram som nyckelfaktorer. Förskollärarna påpekar att det är viktigt med öppna frågor för att uppmuntra egen reflektion hos barnen. Även den fria leken anses vara viktig för vidare bearbetning av informationen. Rekommendation för verksamheten är att tänka på att använda rätt begrepp i arbetet med kemi, att fortsätta dokumentera och reflektera kring de olika aktiviteterna tillsammans med barnen samt ta tillvara och följa barnens intresse.
333

On A-optimal Designs for Discrete Choice Experiments and Sensitivity Analysis for Computer Experiments

Sun, Fangfang 30 August 2012 (has links)
No description available.
334

Essays in Behavioral Economics

Albert, Philipp Arthur 27 July 2022 (has links)
Diese Dissertation untersucht Informationsverarbeitung und die Auswirkungen auf individuelles Entscheidungsverhalten. Anhand von Daten, die durch Experimente gewonnen wurden, wird untersucht wie Individuen von Anreiz- und Marktstrukturen auf Verhalten und dessen Auswirkungen schließen (Kapitel 1), wie sie die Adressaten einer Nachricht berücksichtigen, wenn sie Vorhersagen treffen und aktiv handeln (Kapitel 2) und unter welchen Umständen sie auf Informationen über das Verhalten Anderer reagieren (Kapitel 3). In den ersten beiden Kapiteln finde ich, dass Menschen fehlerhafte Erwartungen bilden, da sie (1) das Ergebnis von Marktinteraktionen falsch vorhersagen und (2) den Informationsgehalt von Informationsquellen falsch einschätzen. Das führt zu nicht-optimalen Investitionsentscheidungen und überschätzten Erwartungen. In dem dritten Kapitel finde ich, dass es sehr kontextabhängig ist, ob Menschen auf Informationen über die Ambitionen anderer Individuen reagieren. In dem quantitativen Kontext von Zielsetzungen gibt es einen starken Effekt durch die Kenntnis über Ambitionen anderer Individuen, in dem qualitativen Kontext von Entscheidungen über die Aufgabenschwierigkeit vertrauen Menschen ihrem eigenen Urteil. / This dissertation studies information processing and its impact on individual decision making. It uses data collected from experiments to examine how individuals extrapolate from incentive and market structures to behavior and outcomes (chapter 1), how they take the audience of a message into consideration when making predictions and taking actions (chapter 2) and under what circumstances they react to information about others’ behavior (chapter 3). In the first two chapters, I find that individuals form biased beliefs due to (1) mispredicting the outcome of market interactions, and (2) misevaluating the informativeness of information structures. This leads to non-optimal investment decisions and overconfident beliefs. In the third chapter, I find that it is very domain specific whether individuals react to information about their peers’ ambitions. In the quantitative domain of goal setting peer effects of ambitions are strong, in the more qualitative domain of difficulty choice individuals trust their own judgment.
335

Fügen dünnwandiger Kupferrohrverbindungen durch WIG-Orbitalschweißen / Joining of copper tubes by TIG orbital welding

Wittig, Sebastian 14 July 2015 (has links) (PDF)
Im Anlagenbau und der Energietechnik werden Rohrleitunen vornehmlich aus nichtrostenden Stählen hergestellt Hierbei hat sich das WIG-Orbitalschweißen als standardmäßiges Fügeverfahren etabliert. Es bietet hohe erreichbare Gütewerte der Fügestelle und eine gute Reproduzierbarkeit der Schweißergebnisse. Aufgrund der positiven Eigenschaften von Kupfer, besteht in einigen Anwendungsbereichen ein gesteigertes Interesse an der Substitution von Rohren aus nichtrostendem Stahl durch Kupferleitungen. Gegenwärtig werden dünnwandige Kupferrohre meist durch Pressfittings, Klemm- sowie Schneidringverschraubungen oder Löten gefügt. Wegen der hohen erreichbaren Gütewerte der Fügeverbindung, ist eine Anwendung des WIG-Orbitalschweißverfahrens auch für Kupferrohre wünschenswert. Ziel dieser Arbeit ist die Bewertung der Schweißversuche zur Etablierung des WIG-Orbitalschweißverfahrens für dünnwandige Kupferrohre. Dazu werden zunächst grundlegende Aussagen über den Rohrleitungswerkstoff Kupfer und das WIG-Orbitalschweißverfahren zusammengetragen. Anschließend werden der Aufbau und die Durchführung der Experimente beschrieben sowie eine Auswertung der Versuchsergebnisse vorgenommen. Die Prüfung der Schweißergebnisse erfolgt durch zerstörungsfreie und zerstörende Prüfverfahren. Soweit vorhanden, wird sich dabei an gebräuchlichen Normenwerken orientiert. Als Ergebnis der Versuche zeigt sich, dass eine sichere Durchschweißung mit einer guten Wurzelausbildung realisierbar ist. Jedoch sind die Schweißnähte sowohl innerlich, wie auch oberflächlich, anfällig für Hohlraumbildung. Innerlich ist eine gleichmäßige Verteilung von Poren, über den gesamten Rohrquerschnitt, zu beobachten. Oberflächlich konzentrieren sich die Unregelmäßigkeiten hauptsächlich auf das oberste Viertel der Schweißnaht, welches in der Rohrposition für Fallendschweißen gefügt wurde. Trotz der detektierten Unregelmäßigkeiten stellt das WIG-Orbitalschweißen ein vielversprechendes Fügeverfahren zum Verbinden dünnwandiger Kupferrohre dar. Bereits denkbare Anwendungen wären Rohre im Niederdruckbereich, welche permanent vom selben Medium durchströmt werden sowie Abgas- und Abwasserleitungen. Aus Korrosionsschutz- und Sicherheitsgründen wird jedoch von einer Durchströmung der Leitungen mit sauren oder toxischen Fluiden abgeraten.
336

Essays on Experimental Methods Applied to Different Environments

Di Paolo, Roberto 16 July 2021 (has links)
El enfoque experimental es el corazón de algunos de los desarrollos más interesantes de la economía. Básicamente, los experimentos se utilizan para generar datos controlados. El término "datos controlados" se refiere al hecho de que la mayoría de los factores en los que influyen las conductas se mantienen constantes, y solo un factor de interés (el "tratamiento'') cambia a la vez. Este es el punto crítico para hacer una inferencia causal. A veces, este proceso de generación ocurre de forma natural (es decir, un "experimento natural''). Sin embargo, la mayoría de las veces, el investigador es el encargado de desarrollar y controlar el proceso de generación. Todas las áreas de la ciencia (incluida la economía) deben considerar todas las metodologías que se pueden aplicar. La teoría, los experimentos de laboratorio, los experimentos de campo, los experimentos online, la neuroeconomía, la investigación observacional y social, las encuestas y más, contribuyen a nuestra comprensión del mundo. En el primer capítulo de a tesis, se presentan resultados experimentales sobre subastas. Se consideran dos tratamientos experimentales: si el comprador prefiere más la calidad a la dimensión del precio, o si este último importa más que la calidad. Los participantes se asignan al azar a uno de estos dos tratamientos y se emparejan en grupos de cinco. Juegan una subasta de períodos múltiples, donde la calidad es exógena asignada en cada ronda y los sujetos presentan una rebaja al precio base anunciado. Las pujas se transforman en puntuaciones que combinan la calidad exógena y la rebaja. El vendedor con la puntuación más alta gana la subasta. Los resultados sugieren que, cuando el peso de la rebaja es mayor, los participantes pujan más cerca del equilibrio. Sin embargo, la probabilidad de obtener un resultado eficiente es mayor cuando se pone más peso en la calidad. En el segundo capítulo analizo los resultados de un experimento en línea en el que los sujetos juegan cuatro versiones del juego Stag-Hunt. Hay tres tratamientos: línea de base, retraso de tiempo y retraso motivado. En el segundo, los sujetos deben esperar 40 segundos antes de elegir una decisión. En el tercero, deben esperar 40 segundos y escribir un texto para motivar sus decisiones. Al final del juego, los participantes informan sobre creencias, preferencias de riesgo y una medida de confianza. El resultado principal es que los sujetos optan por colaborar menos cuando deliberan más. La explicación es que este tratamiento ayuda a los sujetos a comprender que esta es la opción más segura. En el tercer capítulo, los autores estiman el impacto de un programa educativo basado en juegos destinado a promover el uso sostenible del agua. Esto se hizo en la ciudad de Lucca, con miles de alumnos de 2º a 4º de primaria. Los hallazgos indican que los estudiantes del grupo de tratamiento (participantes del programa) mostraron una mayor conciencia sobre el consumo de agua respecto a aquellos estudiantes que no participaron en el programa. Además, encuentran que el efecto positivo aún se observa después de seis meses, lo que sugiere que los programas educativos basados en juegos pueden ser un instrumento eficaz para promover comportamientos prosociales en el consumo de agua.
337

Analýza rizik ve vztahu k různým zaměřením ekonomických experimentů / Risk Analysis in Relation to Various Types of Economic Experiments

Šikula, Pavel January 2014 (has links)
The diploma thesis deals with analysis of risks in relation to various focus (or types) of economic experiments. On the basis of background research suggests entirely new classification of economic experiments and subsequently examines general structure of economic experiment. Performed analysis then identifies major risks of experimental economics, analyses them and proposes possible countermeasures. Outputs of the work substantially enrich and extend current theory. Their utilization is expected in theory and practice, for purpose of scientific research or specific objectives of companies and institutions.
338

Data analysis for quantitative determinations of polar lipid molecular species

Song, Tingting January 1900 (has links)
Master of Science / Department of Statistics / Gary L. Gadbury / This report presents an analysis of data resulting from a lipidomics experiment. The experiment sought to determine the changes in the lipidome of big bluestem prairie grass when exposed to stressors. The two stressors were drought (versus a watered condition) and a rust infection (versus no infection), and were whole plot treatments arranged in a 2 by 2 factorial. A split plot treatment factor was the position on a sampled leaf (top half versus bottom half). In addition, samples were analyzed at different times, representing a blocking factor. A total of 110 samples were used and, for each sample, concentrations of 137 lipids were obtained. Many lipids were not detected for certain samples and, in some cases, a lipid was not detected in most samples. Thus, each lipid was analyzed separately using a modeling strategy that involved a combination of mixed effects linear models and a categorical analysis technique, with the latter used for certain lipids to determine if a pattern of observed zeros was associated with the treatment condition(s). In addition, p-values from tests of fixed effects in a mixed effect model were computed three different ways and compared. Results in general show that the drought condition has the greatest effect on the concentrations of certain lipids, followed by the effect of position on the leaf. Of least effect on lipid concentrations was the rust condition.
339

Consumer demand for Community Supported Agriculture: a comparative study of the Kansas City (USA) and Midi-Pyrenees (France) regions

Baudouin, Quentin January 1900 (has links)
Master of Science / Department of Agricultural Economics / Hikaru H. Peterson / Farmer-to-consumer direct marketing institutions have expanded significantly in the last decades. In particular, Community Supported Agriculture (CSA) has developed exponentially in the US and in Europe. CSAs consist of a contract in which the consumer buys a share of the farm production at the beginning of the season and receive in exchange a bundle of products regularly. CSAs still account for a marginal share of food sales today and many questions remain unanswered, such as the level of knowledge of the general public about CSA, the potential size of the market, its consumer characteristics, and the main motivations and barriers that lead consumers to either join or not join CSAs. This study focused on addressing these questions for the Kansas City area and the central region in France. Another objective was to give recommendations to farmers on how to develop CSAs. Two versions of the surveys were designed and conducted in the US and in France to address the objectives. Particularly, two types of questions were used in order to elicit willingness to pay (WTP): an open-ended question and a choice experiment. A Tobit model and discrete choice models were run to analyze results from the open-ended question and the choice experiment, respectively. Results show that around 80 percent of the population knew little about CSAs. The understanding of the demand for CSAs shows that a potential market, accounting for around 25 percent of the population, exists, but consumers are very exigent and farmers need to provide well-considered contracts to attract consumers. Recommendations to farmers are presented following the 4P method. For the Product, the variety offered seems to be the most important point. For Price, it has been estimated from the demand at $300 in the US and €400 in France for a basic share. Promotion would need to focus on education. Having various delivery locations would be the best option concerning Place; home delivery was found to be unnecessary. Tendencies found in the US and in France were similar except for educational activities: the French are looking more for these opportunities than Americans who care more about convenience.
340

Closing the Loop by Combining UASB Reactor and Reactive Bed Filetr Technology for wastewater Treatment : Modelling and Practical Approaches

Rodríguez-Gómez, Raúl January 2016 (has links)
A laboratory-scale upflow anaerobic sludge blanket (UASB) reactor followed by a packed bed reactor (PBR) filled with Sorbulite® in the lower part and Polonite® in the upper part was used to treat household wastewater in a 50-week experiment. A model was developed to describe the performance of the UASB reactor, including mass transfer through the film around anaerobic granules, intra-particle diffusion and bioconversion of the substrate. In a second model, a numerical expression describing the kinetics occurring in the granules was developed. It includes the resistances through which the substrate passes before biotransformation. These expressions were then linked to governing equations for the UASB reactor in order to describe degradation of the substrate, biomass growth (active and inactive), and variation in granule size over time. A third model was developed to describe the profile of the phosphorus (P) concentration throughout the PBR. In a first attempt, the analytical and numerical model was applied to data taken from previous studies in which UASB reactors were used to treat sugarcane mill wastewater and slaughterhouse wastewater. The results showed good agreement between observed and simulated results. Sensitivity analysis showed that diffusion coefficient and yield were important parameters in the UASB reactor model.The laboratory bench-scale experiment revealed that the combined UASB-PBR system efficiently treated the residential wastewater. Phosphorus, BOD7 and pathogenic bacteria all showed average removal of 99%, while total nitrogen showed a moderate reduction in the system (40%). Application of the numerical solution model to the experimental UASB reactor used resulted in good agreement between simulated and experimental values. Regarding the PBR, the model developed successfully predicted P removal. For both models, the capability and sensitivity analyses identified important parameters. A treatment system aiming to close the loop is suggested based on sequential UASB and PBR with biogas collection, nutrient recycling via sludge and filter media and elimination of pathogenic organisms. / <p>QC 20160226</p>

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