• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 188
  • 157
  • 36
  • 16
  • 14
  • 11
  • 9
  • 4
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • 1
  • Tagged with
  • 502
  • 88
  • 75
  • 72
  • 47
  • 38
  • 38
  • 36
  • 35
  • 31
  • 30
  • 25
  • 25
  • 24
  • 24
  • 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.
71

市場效率和投資人情緒:以期貨和現貨市場間的價格動態調整為例 / Market Efficiency and Investor Sentiment: Evidence from the Pricing Dynamics between Futures and Spot Markets

林楚彬, Lin, Chu Bin Unknown Date (has links)
This study shows that investor sentiment plays an important role in affecting the pricing dynamics between the spot and futures markets. The empirical evidence suggests that investor sentiment has a positive impact on price volatility and the bid–ask spread on both the spot and futures markets, which induces higher arbitrage risk and trading costs during high sentiment periods. As a consequence, during high sentiment periods, informed traders become less willing to leverage their information advantages on the futures market, which diminishes the futures markets’ leading informational role and contributions to price discovery. My findings provide support for the theory of limits to arbitrage.
72

Varied and Novel Activity Selection by Adults with Developmental Disabilities

Buchmeier, Amanda 01 December 2012 (has links)
Basic laboratory research has shown that variability is an operant dimension of behavior (Page & Neuringer, 1985). Applied research on behavioral variability has been conducted with a variety of populations and response topographies; however, no research has been conducted with adults with developmental disabilities, and only one study has targeted activity selection (Cammilleri & Hanley, 2005). In the present study, varied activity selection was reinforced according to a Lag 1 schedule of reinforcement. The present study also evaluated whether selection of novel activities occurred in the absence of differential reinforcement and assessed generalization of varied activity selection. Varied activity selection increased for all participants although prompts to select activities were required for 2 of 3 participants. Few novel selections occurred throughout the study and varied activity selection did not generalize to participants' natural environments. These results suggest that a lag schedule of reinforcement can be used to increase varied activity selection by adults with developmental disabilities but should be implemented in the natural environment.
73

Theoretical and experimental investigation of a novel hydraulically assisted turbocharger system for future automotive applications

Justus, Jack January 2016 (has links)
The work was concerned with the design, analysis and basic demonstration of a novel hydraulically assisted fixed geometry turbocharger system intended to help overcome some of the transient issues associated with current automotive boosting technologies. The novel system was based upon use of relatively lightweight parts, where kinetic energy is recovered during vehicle braking, stored in a simple hydraulic accumulator and then used later on to rapidly accelerate the engine's turbocharger. The turbocharger is fitted with a replacement centre housing enclosing a small impulse turbine, rigidly mounted to the turbocharger shaft and powered by a jet of oil. The aim is one of helping the engine to accelerate the vehicle while operating in a region of much higher brake efficiency due to the reduction in exhaust backpressure when compared with competing variable geometry and/or compound boosting technologies. The specific tasks involved concept design and computational analysis, including specification of the turbine type and geometry together with the associated hydraulic parts. A production turbocharger was reverse engineered to confirm the feasibility of packaging the hydraulic turbine system into the centre housing of a typical fixed geometry design. Finally an experimental rig was designed and manufactured to allow basic demonstration of the system, with speeds of up to ~90000 rpm @ 200 bar pressure from the pump via the accumulator achieved in ~0.8 seconds and clear potential for further optimisation. This hydraulic boosting system is capable of attaining 70% efficiency (a product of 0.85 from the oil pump, 0.95 from the hydraulic accumulator and 0.88 of Pelton wheel). The system has higher power density at low cost compared to the main competitor ‘E Boosting - with efficiency in the region of 90%’. The cost of E boosting and need for 48 volt battery makes it less favourable compared to the hydraulic turbine system. The concept has been shown to offer significant potential to assist a turbocharger to spool up via a Novel Hydraulic Kinetic Energy Recovery System approach.
74

Governança corporativa e eficiencia informacional

Oliveira Neto, José Carneiro da Cunha 16 December 2010 (has links)
Tese (doutorado)—Universidade de Brasília, Faculdade de Economia, Administração, Contabilidade e Ciência da Informação e Documentação, Programa de Pós-Graduação em Administração, 2010. / Submitted by Albânia Cézar de Melo (albania@bce.unb.br) on 2011-10-03T14:58:13Z No. of bitstreams: 1 2010_JoseCarneirodaCunhaOliveiraNeto.pdf: 931070 bytes, checksum: a8adc0ba6d2f96f0fe09dd274b28b826 (MD5) / Approved for entry into archive by LUCIANA SETUBAL MARQUES DA SILVA(lucianasetubal@bce.unb.br) on 2011-10-03T16:10:37Z (GMT) No. of bitstreams: 1 2010_JoseCarneirodaCunhaOliveiraNeto.pdf: 931070 bytes, checksum: a8adc0ba6d2f96f0fe09dd274b28b826 (MD5) / Made available in DSpace on 2011-10-03T16:10:37Z (GMT). No. of bitstreams: 1 2010_JoseCarneirodaCunhaOliveiraNeto.pdf: 931070 bytes, checksum: a8adc0ba6d2f96f0fe09dd274b28b826 (MD5) / This thesis aims to analyze the relationship between corporate governance and information efficiency. Corporate governance can be defined as a set of instruments designed to ensure the suppliers of capital receipt of any revenue generated by their investments. For this, a company with higher levels of governance adopts standards of disclosure, greater transparency in decision making and straight relationship rules between management and capital providers. In Brazil, the institutional structures that underpin the functioning of the differentiated governance began to be developed further since 2001, with the creation of Novo Mercado and different levels of governance and the creation of the Câmara de Arbitragem do Mercado (CAM). To work, the structures of ensuring compliance with the promise of best practices should be accepted as effective by market participants. Accordingly, there is a process of building the reputation of the new institutions created to support the market for a differentiated governance. When you have established credibility, how economic agents process new information regarding these companies should be influenced, since the new rules limit the universe of possible deviations from the administration or majority stockholder, which reduces the costs associated with process incorporation of new information to the company's assets. As a basic hypothesis, this thesis proposes that firms with higher levels of governance, since they have lower costs associated with the incorporation of exogenous shocks, should lead the market to absorb more efficiently the impacts generated by new information. To examine this hypothesis, two basic models were built. The first, introduced in Chapter 3 assesses the market for corporate governance has gained credibility with the participants of the stock market, the results indicate that even after controlling for number of companies, the risk profile of the different market governance has improved consistently when compared with the traditional market. Already in Chapter 4 of the best informational efficiency hypothesis is tested, that are used for intraday frequency of 15 minutes. The hypothesis is that improved corporate governance reduces the costs associated with incorporating new information to the assets of the company, so companies with better governance have higher level of informational efficiency. The cointegrating relationship between series was tested using the Engle-Granger method in two stages. The Vector Error Correction (VECM) and Granger causality test does not allow rejection of the hypothesis of informational efficiency of the market better governance differently. To estimate the VECM used a bivariate BEKK GARCH model. The results indicate that the IGC finds its equilibrium price and the fastest IbrX converges to the equilibrium indicated by the IGC. The thesis is divided into five chapters, the introduction provided in Chapter 1, the theoretical model is developed during the literature review in Chapter 2, Chapter 3 assesses the evolving relationship between market risk and traditional governance differentiated, the Chapter 4 studies the effect of leadership presence and Chapter 5 presents the overall findings and recommendations, after the bibliography is listed. _________________________________________________________________________________________ RESUMEN / Esta tesis tiene como objetivo analizar la relación entre gobernanza empresarial y eficiencia de la información. La gobernanza empresarial puede ser definida como un conjunto de instrumentos destinados a garantizar la recepción de los proveedores de capital de los posibles ingresos generados por sus inversiones. Para ella, una empresa con mayores niveles de gobierno adopta normas de divulgación más amplias, claras y rígidas, una mayor transparencia en la toma de decisiones y la relación entre la administración y los inversores. En Brasil, las estructuras institucionales que sustentan el funcionamiento de la gestión diferenciada empezó a ser desarrollado cerca de 2001, con la creación del Novo Mercado y diferentes niveles de gobernanza, además la creación del mercado de la Câmara de Arbitragem do Mercado (CAM). Para el trabajo, las estructuras de garantiza el cumplimiento de la promesa de mejores prácticas debe ser aceptada como efectiva por los participantes del mercado. En consecuencia, hay un proceso de construcción de la reputación de las nuevas instituciones creadas para apoyar el mercado de gobernanza empresarial diferenciada. Cuando haya establecido la credibilidad, la forma como los agentes económicos procesan la nueva información respecto a estas empresas deben ser influenciadas, ya que las nuevas reglas limitan el universo de posibles desviaciones de la administración o de los accionistas mayoritarios, lo que reduce los costos asociados con el proceso incorporación de nueva información a los activos de la empresa. Como hipótesis de base, esta tesis propone que las empresas con mayores niveles de gobierno, ya que tienen menores costos asociados con la incorporación de los choques exógenos, debe liderar el mercado para absorber de manera más eficiente los impactos generados por la nueva información. Para examinar esta hipótesis, dos modelos básicos fueron construidos. El primero, presentado en el capítulo 3 se evalúa el mercado de la gestión empresarial ha ganado credibilidad con los participantes del mercado de valores, los resultados indican que, incluso después de controlar por número de empresas, el perfil de riesgo de la gobernanza del mercado de diferentes ha mejorado constantemente cuando en comparación con el mercado tradicional. Ya en el Capítulo 4 la hipótesis mejor eficiencia informativa se prueba, para lo que se utilizan dados en la frecuencia intradía de 15 minutos La hipótesis es que una mejor gobernanza empresarial reduce los costes asociados a la incorporación de nueva información a los activos de la empresa, por lo que las empresas con mejor gobernanza tienen un mayor nivel de eficiencia informativa. Para analizar la relación de largo plazo entre IBrX y de la CIG, la relación de cointegración, el método de Engle-Granger en dos etapas fue utilizado. El vector de corrección de errores (VECM) y la prueba de causalidad de Granger no permite rechazar la hipótesis de eficiencia informativa de las empresas con mejor gobernanza. Para estimar el VECM utiliza un modelo GARCH bivariante BEKK. Los resultados indican que el IGC encuentra su precio de equilibrio más rápido y IBrX converge al equilibrio indicado por lo IGC. La tesis se divide en cinco capítulos, la introducción en el Capítulo 1, el modelo teórico se desarrolla durante la revisión de la literatura en el Capítulo 2, el Capítulo 3 se evalúa la evolución de la relación entre el riesgo de mercado y de gobierno tradicionales diferenciados, el Capítulo 4 estudia la presencia de lead lag y en Capitulo 5 son presentadas las conclusiones generales y recomendaciones. después de lo cual la bibliografía es presentada. / A presente tese tem como objetivo analisar a relação entre governança corporativa e eficiência informacional. A governança corporativa pode ser definida como um conjunto de instrumentos que visam garantir aos fornecedores de capital o recebimento dos eventuais benefícios produzidos por seus investimentos. Para isso, uma empresa com níveis mais elevados de governança adota normas de divulgação de informações mais amplas, claras e rígidas, maior transparência no processo decisório e na relação entre administração e fornecedores de capital. No Brasil, as estruturas institucionais que fundamentam o funcionamento do mercado de governança diferenciada começaram a ser mais desenvolvidas a partir de 2001, com a criação do Novo Mercada e níveis diferenciados de governança e pela criação da Câmara de Arbitragem do Mercado (CAM). Para que funcione, as estruturas de garantem o cumprimento das promessas de melhores práticas devem ser aceitas como eficazes por parte dos participantes do mercado. Nesse sentido, há um processo de construção da reputação das novas instituições criadas para fundamentar o mercado de governança diferenciada. Após estabelecida a credibilidade, a forma como os agentes econômicos processam novas informações referentes a essas empresas deve ser influenciada, visto que as novas regras limitam o universo de desvios possíveis por parte da administração ou acionista majoritário, o que reduz os custos associados ao processo de incorporação de novas informações aos ativos da empresa. Como hipótese básica, a presente tese propôs que empresas com níveis mais elevados de governança, por possuírem menores custos associados à incorporação de choques exógenos, devem liderar o mercado ao absorverem de maneira mais eficiente os impactos gerados pelas novas informações. Para avaliar essa hipótese, dois modelos básicos foram construídos. O primeiro, apresentado no Capítulo 3 avalia se o mercado de governança corporativa tem ganhado credibilidade perante os participantes do mercado de capitais, os resultados indicam que mesmo quando controlado o número de empresas, a perfil de risco do mercado de governança diferenciada tem melhorado consistentemente quando comparado com o mercado tradicional. Já no Capítulo 4 a hipótese de melhor eficiência informacional é testada, para isso são utilizados dados intradiários em freqüência de 15 minutos. A hipótese testada é de que um melhor nível de governança corporativa reduz os custos associados à incorporação de novas informações aos preços dos ativos da empresa, assim empresas com melhor nível de governança têm maior eficiência informacional. A relação de cointegração entre as séries foi testada com o uso do método Engle-Granger em dois estágios. O Vetor de Correção de Erros (VECM) e o teste de causalidade de Granger não permitem a rejeição da hipótese de melhor eficiência informacional do mercado de governança diferenciada. Para estimativa do VECM utilizou-se um modelo GARCH bivariado BEKK. Os resultados indicam que o IGC encontra seu preço de equilíbrio mais rápido e que o IBrX converge para a relação de equilíbrio apontada pelo IGC. A tese está dividida em cinco capítulos, sendo a introdução apresentada no Capítulo 1, o modelo teórico é desenvolvido durante a revisão da literatura no Capítulo 2, o Capítulo 3 avalia a evolução da relação de risco entre o mercado tradicional e o de governança diferenciada, o Capítulo 4 estuda a presença do efeito liderança e o Capítulo 5 apresenta as conclusões gerais e recomendações, ao fim a bibliografia utilizada é listada. __________________________________________________________________________________________ ABSTRACT
75

Avaliação da resistência de ligações com parafusos auto-atarraxantes do tipo torx solicitados por tração axial, em peças de madeira / Evaluation of timber strengt of connections with torx lag screws requested by axial withdrawal in wooden pieces

Ricardo Rizzo Correia 07 June 2002 (has links)
A aplicação da madeira como material estrutural na construção civil é amplamente difundida em coberturas residenciais e comerciais, construção de residências ou em obras de grande porte como pontes. Freqüentemente ocorre a necessidade de ligações entre peças estruturais. Uma das possibilidades de ligação é a utilização de parafusos auto-atarraxantes solicitados por esforços de tração, diferente da maioria dos casos de ligações, nas quais pinos estão solicitados por forças laterais. Um tipo particular de parafuso auto-atarraxante é o torx, que possui rosca em toda a sua extensão, possibilitando uma outra forma de arranjo de ligação que facilita a execução das ligações entre as peças estruturais. Este parafuso possui uma grande resistência que traz à industrialização das estruturas de madeiras. O objetivo desta pesquisa é determinar, de maneira experimental, a resistência de ligações utilizando parafusos torx auto-atarraxantes submetidos a esforços axiais de tração, em peças de madeira, avaliando a influência de diversos fatores, tais como: direção de fixação dos parafusos em relação às fibras, efeito de grupo teor de umidade, massa específica da madeira e espaçamentos entre parafusos. Foram utilizadas as espécies: Pinus Taeda (Pinus taeda L.), Eucalipto Grandis (Eucalyptus grandis) e Cupiúba (Goupia glabra). / Timber as a structural material civil in construction is widely used in framework, construction of houses or larger construction as bridges. The use of connections among structural members is frequently required. One of the connection possibilities is the use of lag screws in axial withdrawal load, differently from most cases of connections in which they are laterally loaded. A peculiar type of lag screw is the torx, which possesses thread along its extension, making possible another form of connection arrangement that facilitates the execution of the connections among the structural pieces. This lag screw has a high strength and facilitates the industrialization of timber structures. The aim of this research is to determine, in an experimental way, the strength of connections using torx lag screws in withdrawal loads, evaluating the influence of several factors, such as direction of the lag screws in relation to grain, group effect, moisture content, density of wood and spacings among screws. The species used were: Pinus Taeda (Pinus taeda L.), Eucalipto Grandis (Eucalyptus grandis) and Cupiúba (Goupia glabra).
76

Preservation of Midlatitude Ice Sheets on Mars

Bramson, A. M., Byrne, S., Bapst, J. 11 1900 (has links)
Excess ice with a minimum age of tens of millions of years is widespread in Arcadia Planitia on Mars, and a similar deposit has been found in Utopia Planitia. The conditions that led to the formation and preservation of these midlatitude ice sheets hold clues to past climate and subsurface structure on Mars. We simulate the thermal stability and retreat of buried excess ice sheets over 21Myr of Martian orbital solutions and find that the ice sheets can be orders of magnitude older than the obliquity cycles that are typically thought to drive midlatitude ice deposition and sublimation. Retreat of this ice in the last 4Myr could have contributed similar to 6% of the volume of the north polar layered deposits (NPLD) and more than 10% if the NPLD are older than 4Myr. Matching the measured dielectric constants of the Arcadia and Utopia Planitia deposits requires ice porosities of similar to 25-35%. We model geothermally driven vapor migration through porous ice under Martian temperatures and find that Martian firn may be able to maintain porosity for timescales longer than we predict for retreat of the ice.
77

Kan man se en förändring av Okuns lag över tid? : En empirisk analys mellan fyra länder

Insulander, Karin January 2017 (has links)
Syftet med uppsatsen är att undersöka arbetslöshetens påverkan av konjunktursvängningar, där studiens teoretiska utgångspunkt är Okuns lag. Arbetet är avgränsat till fyra länder: Sverige, Australien, Japan och USA. De valda länderna representerar varsin världsdel, är medlemmar i OECD, är av en hög utvecklingsgrad och innehar mycket data på de valda undersökta faktorerna. En förväntan finns att det uppstår en variation på sambandet då de valda länderna har olika uppbyggnader i till exempel arbetsmarknaden. Tidigare studier i ämnet Okuns lag ger en inblick i hur det kan ha skett en förändring över tid och mellan länder. Frågeställningen undersöks och besvaras med hjälp av en empirisk undersökning med årlig data för de fyra länderna utförd under en tidsperiod på 44 år, som är uppdelad i två perioder hämtad från OECDs databas. Regressionsanalysen bekräftar att det finns ett negativt samband mellan variationen i kortsiktig tillväxt och arbetslöshet för samtliga länder. Däremot gav samtliga länder ett resultat som inte var signifikant på granskningen om en förändring skett mellan de två undersökta perioderna. Detta leder till ett antagande att det inte skett en förändring över tid rent resultatmässigt. Den här studien tar upp troliga förklaringar till variationen i sambandet som finns mellan länderna, detta för att kunna ge exempel på möjliga bakomliggande faktorer till sambandet.
78

Studies on Circadian Clock RNA Methylation and Micturition Rhythm / 概日時計のRNAメチル化とミクチュリション日内変動の研究

Itoh, Kakeru 23 March 2021 (has links)
京都大学 / 新制・課程博士 / 博士(薬学) / 甲第23148号 / 薬博第848号 / 新制||薬||242(附属図書館) / 京都大学大学院薬学研究科薬学専攻 / (主査)教授 土居 雅夫, 教授 中山 和久, 教授 竹島 浩 / 学位規則第4条第1項該当 / Doctor of Pharmaceutical Sciences / Kyoto University / DFAM
79

Är den enkla vägen den smartaste vägen? : En intervjustudie av blåljuspersonalens perspektiv på den skärpta lagen, blåljussabotage

Lissdaniels, Lovisa, Sjöberg, Frida January 2020 (has links)
I över 150 år har slutsatsen varit densamma, att skärpta straff inte reducerar brottsligheten. Trots att majoriteten av den forskning som finns inom området påvisat att det inte är ett framgångsrikt verktyg, fortsätter vi i samma riktning. Syftet med studien var att undersöka huruvida blåljuspersonal upplever ökad trygghet i samband med den skärpta lagen, blåljussabotage. Vi ämnade att skapa en djupare förståelse för erfarenheter och upplevelser av blåljussabotage, samt åsikter om skärpta straff ur en preventiv aspekt. Studien har genomförts med semistrukturerade intervjuer inom polisoch ambulansverksamhet. Respondenterna anser inte att straffskärpningen fungerar avskräckande och upplever inte en ökad trygghet, vilken lagen hade för syfte att uppnå. Däremot finns en positiv inställning till lagen ur upprättelsesynpunkt, samt att det för polisen utökar deras befogenheter. Fokus bör ligga på att de tilltag som görs grundar sig i forskning för att implementera sådant som påvisats fungera, snarare än kundnöjdhet och skärpta straff.
80

Obehöriga transaktioner med kontokort och BankID : Vem betalar när tjuven eller bedragaren tar dina pengar? / Unauthorized transactions with credit card and BankID : Who pays when the thief or fraudster takes your money?

Andrée, Victor January 2021 (has links)
Den teknologiska utvecklingen har medfört att människor gått från att betala med kontanter till att i stället använda kontokort och elektronisk underskrift. Faktum är att lagstiftarens intention är att främja nya sätt att betala för att minska användningen av kontanter i samhället. Kontantstölderna har visserligen minskat, men i och med ökningen av moderna betalningsmetoder har i stället antalet bedrägerier och kortstölder ökat. Under de senaste åren har det kontinuerligt varnats för obehöriga transaktioner med såväl kontokort som BankID. Om du råkar ut för att en tjuv eller en bedragare tar dina pengar – vem betalar då? Frågan besvaras genom att tillämpliga reglerna i 5 a kap. betaltjänstlagen. Svaret är att kontohavarens bank betalar som huvudregel. Banken har dock inte samma skyldighet att betala om kontohavaren hanterat sitt kontokort eller sin elektroniska underskrift grovt oaktsamt eller särskilt klandervärt. Det är sålunda avgörande att känna till vad begreppen innebär för att fastställa när banken alternativt kontohavaren ska stå för den ekonomiska skadan. I uppsatsen fastställs att vara grovt oaktsam innebär en hög grad av kvalificerad oaktsamhet. Att vara särskilt klandervärd innebär att vara likgiltig inför risken för obehöriga transaktioner. Det krävs alltså en omfattande grad av oaktsamhet för att bedömas som särskilt klandervärd. I uppsatsen framkommer det dock att tröskeln för att bedömas särskilt klandervärd placerats låg i avgöranden från Allmänna reklamationsnämnden och domar från tingsrätterna. Effekten av en låg tröskel blir att kontohavare oftare får stå för den ekonomiska förlusten. Det kan leda till att kontohavare inte upplever att moderna sätt att betala är tillräckligt säkra och lagstiftarens intention att främja nya sätt att betala motverkas. I uppsatsen fastställs även att betalningsansvaret är strängare för innehavaren av elektronisk underskrift jämfört med innehavaren av kontokort. Anledningen är att bedrägerier med elektronisk underskrift ofta bedöms som behöriga transaktioner. Effekten av att en transaktion bedöms behörig är att 5 a kap. betaltjänstlagen inte blir tillämplig eftersom bestämmelserna enbart tilllämpas på obehöriga transaktioner. En annan anledning är att tröskeln för att bedömas särskilt klandervärt med elektronisk underskrift i praxis placerats lågt i jämförelse med kontokort. Därutöver har innehavaren av elektronisk underskrift sällan någon möjlighet att styra om vederbörande ska bedömas särskilt klandervärd eller grovt oaktsam, eftersom omständigheterna som beaktas i praxis ligger utanför kontohavarens kontroll. Det leder till att risken för att ersättning uteblir är högre för innehavaren av elektronisk underskrift.

Page generated in 0.0372 seconds