• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 770
  • 563
  • 153
  • 99
  • 59
  • 59
  • 41
  • 41
  • 40
  • 34
  • 28
  • 22
  • 13
  • 9
  • 8
  • Tagged with
  • 2179
  • 461
  • 263
  • 202
  • 187
  • 164
  • 155
  • 145
  • 144
  • 134
  • 122
  • 111
  • 108
  • 105
  • 103
  • 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.
101

Chefskap eller inte : Om vad upplevelsen av socialt stöd i tonåren har haft för betydelse för det framtida yrkeslivet

Dahl, Fanny January 2013 (has links)
Synen en individ har på arbete och tron på sin förmåga inom yrkeslivet formas i många fall redan under tonåren. Anknytningsrelationerna till föräldrarna och det sociala stödet inom en familj påverkar den enskilda individens karriärsidentitet och framtida yrkesval. Studien syftar till att belysa aspekter av hur den upplevda synen på tonåren i efterhand gällande familjerelationer, skolgången och synen på arbete har spelat roll för enskilda individers nuvarande yrkesval, karriärsidentitet, och tron på den egna förmågan. Studien har genomförts genom kvalitativa intervjuer av en grupp chefer (med 5 chefer och 4 icke-chefer), och visade bland annat på att cheferna upplevde ett större socialt stöd från sin familj under tonåren, jämfört med icke-cheferna. Resultatet diskuteras utifrån aspekter som berör det sociala stödet betydelse för framtida karriärsval, och vikten av skolans betydelse för framtida yrkesval och karriärsidentitet. Vilket ska ha en stor betydelse för individer som har en lägre socioekonomisk bakgrund
102

Modelling the surface potential of Langmuir monolayers

Gilbert, Freestone Bayes January 1995 (has links)
No description available.
103

On the long-term equilibrium of mortality rates among multiple populations

Xing, Guangyu 24 June 2016 (has links)
As human life expectancy continues to increase, longevity risk has become a major concern for pension plan sponsors and annuity providers. To hedge the risk, longevity-linked securities have been developed. Since these securities often have payoffs linked to mortality rates of multiple populations, it is important to investigate the relationship between them. In this thesis, we use England and Wales (EW) and Canadian mortality data for illustration. We consider the long-term equilibrium between the mortality indexes of the two populations through cointegration analysis. Our test shows that structural change occurred in the equilibrium. To capture changes in both equilibrium and autoregression structure, we adopt the Threshold Vector Error Correction Model (TVECM). We find that the TVECM model provides adequate fit to our data. This model is further applied to pricing an illustrative longevity bond. Our numerical results indicate that the changes in the long-term equilibrium have a significant impact on longevity bond prices. / October 2016
104

Efeito da irradiação com lasers de alta potência na adesividade do cimento resinoso às paredes do interior do canal radicular e análise da interface adesiva / In vitro bond strenght of an epoxy resin-based root canal sealer to root dentin irradiated with High-Power lasers and adhesive interface analyses

Cruvinel, Pedro Bastos 28 March 2016 (has links)
O objetivo desse estudo foi avaliar in vitro, a ação dos lasers de alta potência (Nd:YAG e diodo 980nm), associados ao carvão mineral como fotopotencializador, sobre a adesividade do cimento endodôntico, por meio do teste de pushout, e na interface dentina/material obturador, por meio de microscopia confocal a laser. 50 caninos foram instrumentados com sistema Mtwo até #50.04 e irrigados com hipoclorito a 1% a cada troca dos instrumentos. Os espécimes foram distribuídos em 5 grupos (n=10): GI - controle EDTAC, GII - EDTAC e laser Nd:YAG, GIII - EDTAC e laser diodo 980 nm, GIV - EDTAC, laser Nd:YAG e carvão mineral 5 g/100mL, e GV - EDTAC, laser diodo 980 nm e carvão mineral 5 g/100 mL. As aplicações de laser foram na potência de 1.5 W, frequência de 100 Hz pulsátil e fibra de 200&mu;m, por 16 segundos em movimentos elípticos (8 s no sentido coroa-ápice e 8 s no sentido ápice-coroa). Após, os espécimes foram obturados com cimento AH Plus, pela técnica de condensação lateral ativa. As raízes foram seccionadas no sentido transversal, em slices de 1mm de espessura, e submetidas ao teste de pushout em máquina universal de ensaios e o tipo de falha foi analisado em microscópio confocal a laser, e se determinou a profundidade e a uniformidade dos tags de cimento na interface dentina/material obturador. Os dados foram analisados por meio do teste ANOVA a nível de significância de 5%, seguidos dos testes de Kruskal-Wallis, Dunn e Tukey (para a comparação dos grupos). O GI apresentou a maior a resistência de união do cimento à dentina que o tratamento somente com EDTAC 17% (17,21 ± 21,75 MPa), sendo semelhante ao GII (12,21 ± 18,20 MPa) e ao GIV (14,92 ± 28,06 MPa), ambos tratados com laser Nd:YAG, com exceção do GIV, que foi adicionado de carvão mineral. O GV (8,75 ± 13,42 MPa) apresentou resultados similares aos dos grupos GII e GIV, mas a mesma similaridade foi observada quando comparado ao GIII (7,11 + 11,28 MPa), que apresentou os piores resultados. O terço apical (23,27 ± 29,21 MPa) apresentou valor de resistência de união maior que o cervical (5,92 ± 5,33 MPa) e médio (6,93 ± 7,11MPa), que foram semelhantes entre si (p>0,05). Houve predominância de falhas mistas, seguidas das coesivas. O GII (86,27&micro;m) apresentou os maiores valores de penetração de tags, com diferença estatisticamente significante em relação aos GIII (51,57&micro;m), IV (36,77&micro;m) e V (32,37&micro;m) (p<0,05). O GI (71,63&micro;m) não apresentou diferenças estatisticamente significantes em relação ao II e III (p>0,05). O GIV apresentou os menores valores, sem diferenças do III e V, (p>0,05). O terço cervical (58,44&micro;m) apresentou os melhores valores, seguidos dos terços médio (45,02&micro;m) e apical (42,24&micro;m) (p>0,05). Concluiu-se que o tratamento com laser Nd:YAG associado ou não ao carvão mineral, apresentou melhores resultados de força adesiva que o tratamento com laser diodo 980nm, exceto quando esse foi adicionado do carvão mineral. O grupo controle e o laser diodo 980nm apresentaram menores quantidades de falhas adesivas e maiores quantidades de falhas mistas comparados aos demais grupos. Ambos os lasers não interferiram de maneira negativa na penetração de cimento se comparados ao grupo controle, no que se relaciona à resistência adesiva do cimento obturador. / The aim of this study was to evaluate in vitro the influence of high-power lasers (Nd:YAG and diode 980nm) associated with mineral coal as fotopotencializer on Bond strenght of an epoxy resin-based root canal sealer to root dentin, using the push-out test, and on the dentin/filling material interface, using confocal laser microscopy. For this purposes, 50 canines were instrumented with Mtwo Rotary system up to #50.04 instrument, irrigating with sodium hypoclorite 1% at each instrument exchange. The specimens were randomly assigned to 5 groups (n=10), according the treatment of root canal dentin: group I - control EDTAC, group II - EDTAC and Nd:YAG laser, group III - EDTAC and diode laser 980 nm, group IV - EDTAC, Nd:YAG laser and mineral coal 5 g/100 mL, and group V - EDTAC, diode laser 980 nm and mineral coal 5 g/100 mL. All the lasers application was assigned according to the parameters: 1.5 W of power, 100 Hz pulsatile frequency and 200 &micro;m fiber, for 16 seconds in eliptical movements (8 s crown-down direction and 8 s apex-crown direction). Following irradiation, the canals were filled with active lateral condensation of AH Plus sealer and gutta-percha cones. After, the roots were sectioned transversally to obtain 1mm-thick slices. One of two slices from each third were subjected to a push-out test in a universal testing machine and the failure mode was analyzed with confocal laser microscopy and classified as: adhesive to the filling material, adhesive to dentin, cohesive in the filling material and mixed. The remaining slice was analyzed by confocal laser microscopy to evaluate the penetration and homogeneity of the perimeter of the root canal cross-section with sealer tags, at the dentin/filling material interface. All data were analyzed by ANOVA (at 5% significance level) following the Kruskal-Wallis, Dunn and Tukey tests (for groups comparation). Any of the proposing treatments increased more Bond strength of the sealer to root dentin that treatment with only EDTAC 17% (17.21 ± 21.75 MPa), similar to the group II (12.21 ± 18.20 MPa) and group IV (14.92 ± 28.06 MPa), both treated with Nd: YAG laser, with the exception of group IV, which was added to mineral coal. The group V (8.75 ± 13.42 MPa) had similar results to the groups II and IV, but the same similiarity were found when compared with group III (7.11 + 11.28 MPa), with lower results. Regarding the root thirds, the apical third (23.27 ± 29.21 MPa) presented a statistically higher value on Bond strenght than the cervical third (5.92 ± 5.33 MPa) and middle third (6.93 ± 7, 11 MPa) (p> 0.05). It was observed in general that there was a predominance of mixed failures, followed by cohesive failures. The lowest amount were the adhesive failures. Group II (86.27&micro;m) showed the highest tags penetration values, with a statistically difference to the group III (51.57 &micro;m), IV (36.77 &micro;m) and V (32.37 &micro;m) (p < 0.05). Group I (71.63 &micro;m) was statistically similar to groups II and III (p> 0.05). Group IV had the lowest values and was statistically similarity to groups III and V (p> 0.05). The cervical third (58.44 &micro;m) showed best values, followed by the middle third (45.02mm) and apical third (42.24 &micro;m) (p> 0.05). It was concluded that the treatment with Nd:YAG laser provides better results than the diode 980 nm laser, except when was added mineral coal. The control and diode 980 nm laser groups presented less adhesive failures and more mists failures than the other groups. Both lasers did not interfere negatively compared to the control group
105

Sociétés et cautionnement / Companies and surety bond

Chieudji Nguedou, Christelle 07 December 2018 (has links)
L’importance du cautionnement pour les sociétés est indéniable. En plus de contribuer à l’essor de ces dernières par l’accès au crédit, le cautionnement s’impose comme un levier de célérité et de simplicité, atouts majeurs dont requiert le monde des affaires. Cependant, son implémentation dans le cadre des sociétés ne va pas sans poser des difficultés. En effet, l’articulation du cautionnement au sein des sociétés suscite une multitude de controverses et d’ambiguïtés. La combinaison des règles du droit des sociétés et de celles des sûretés n’est pas toujours empreinte d’homogénéité. La complexité de la mise en œuvre du cautionnement au sein des sociétés prend un relief particulier quand il s’agit d’ajouter au panel des règles existantes, les multiples productions jurisprudentielles et les innombrables apports de la doctrine. Ces diverses confrontations dépouillent la matière de sa fluidité, de sa cohérence et par là-même, de son efficacité. Son essence première s’en trouve entachée et le seul trait qui semble ne souffrir autant de reproches est son caractère singulier. L’état des lieux actuel révèle que la mise en œuvre du cautionnement dans les sociétés manque de clarté. Les incessantes interventions du législateur, les désaccords entre les acteurs juridiques, tendent à « polluer » son régime et à le compromettre, ce constat étant valable dans ses deux variantes, que le cautionnement soit donné par une personne physique, le dirigeant social, ou par une personne morale, la société. En pareil contexte, il est impératif de redonner son éclat au cautionnement. / The importance of surety bond for companies is undeniable. In addition to contributing to the growth of the latter through access to credit, surety bond is a lever of speed and simplicity, which are major assets required by the business world. However, its implementation in the context of companies is not without difficulties. Indeed, the articulation of surety bond within companies gives rise to a multitude of controversies and ambiguities. The combination of corporate law and security law rules is not always uniform. The complexity of the implementation of surety bond within companies takes on particular importance when it comes to adding to the panel of existing rules, the multiple productions of case law and the countless contributions of doctrine. These various confrontations deprive the material of its fluidity, its coherence and, consequently, its effectiveness. Its primary essence is tainted by it and the only trait of character that seems not to suffer so much reproach is its singular character. The current inventory shows that the implementation of surety bond in companies is unclear. The incessant interventions of the legislator, the disagreements between the legal actors, tend to pollute his regime and compromise it, this observation is valid in these two variables, whether the assurance is given by a natural person, the company director or by a legal person, the company. In such a context, it is imperative to restore the surety bond to its former glory.
106

The South African government auction mechanism: inference from cross-country analysis

Du Plessis, Johannes Jonathan 03 June 2013 (has links)
Thesis submitted in partial fulfilment of the requirements for the degree of Master of Management in Finance and Investment in the faculty of Commerce, Law and Management, Wits Businesss School, University of the Witwatersrand, 2012. / Idiosyncratic considerations relevant to South Africa’s economic and legal framework, as well as determining factors taken from the financial markets and the asset being auctioned are used to critically review the current auction mechanism used by the South African government to borrow funds publicly. A logistic regression with panel data is used in the empirical analysis. The dependent variable has a dichotomous outcome of uniform-price and discriminatory auction mechanisms. Data from 43 different countries over the period 2005 to 2011 are used for the analysis. It was hypothesized that countries with higher uncertainty about the price of their public debt, should use the auction mechanism that reduces under-pricing. Results from the logit regression supported this view. Upon comparing South Africa’s profile with the logit regression results, alongside a review of the literature, it becomes apparent that the proposed model does not provide a definitive answer. However, the model does aid policymakers’ decision on which auction mechanism should be preferred over the other for South Africa.
107

Performance determinants of local currency bond markets in African emerging economies

Ahwireng-Obeng, Shirley Asabea January 2016 (has links)
Submitted in accordance with the requirement for the degree of Doctor of Philosophy In Business Administration At the University of the Witwatersrand Johannesburg / Generating sufficient domestic revenues to finance economic growth has been a critical hurdle for many African countries and, for decades, foreign capital has complemented domestically generated resources to finance growth. However, global financial crises over the past few decades tend to curtail, if not dry up the flow of capital to African governments. The unreliability of foreign capital with its attendant strings and sudden stops in the event of economic and political crisis has spurred the need for alternative sources of financing development. Despite the realisation that bond markets provide a viable source of funds for the African continent, the literature on the importance of bond market development and its interaction with other sources of funding remains underexplored. Moreover, the sparse empirical literature about bond market development in Africa is vague and largely overlooked. At the same time, knowledge of African bond markets is vital for channelling funds not only to efficient agents in particular, but also for fostering transparency and the flow of information within the continent’s capital markets. This thesis endeavours to address the vacuum apparent in extant literature and proposes a theoretical framework through a thorough assessment of the determinants of bond market development in African emerging market economies. The thesis examines four critical pillars of bond market development: (a) the environment for the creation of bond markets; (b) the relative performance and characteristics of bond markets across and within developing and developed economies; (c) the modelling of bond markets and (c) the institutional factors that underpin the efficient functioning of bond markets. Using macroeconomic, social, institutional and historical data on local currency bond markets from 26 African economies and 49 listed firms, this thesis extends previous studies on bond market determinants through tighter robustness measures by accounting for downside risk in a generalized methods of moments (GMM) and a feasible generalized least squares estimator (FGLSE) framework. Further, differential analysis of government and corporate bond markets are carried out, given their different investment horizons and issuance. The results suggest that from a macroeconomic perspective, inflation, central government debt, GDP, external debt, GDP per capita and fiscal balance are important drivers of local currency bond market development in African economies. Moreover, political unrest, governance, religion, former colonial ties and culture are institutional factors that exert statistically significant effects on local currency bond market performance in Africa. From a demand viewpoint, the study finds that firm level factors that influence bond market performance are firm risk, size, profitability and age. The results from this study are of importance to capital market participants, investors, regulators and policy makers who seek to address the perennial constraints to development occasioned by lack of capital. A number of policy measures for boosting bond market performance such as stable macroeconomic environments, reform of capital market rules and cross listing are discussed in the final chapter. JEL CLASSIFICATION: International Economics; Financial Economics; Economic Development; Innovation; Technological Change; and Growth. KEYWORDS: Africa; Emerging economy; Bond market; Institutions; Local Currency Bond Market; Performance; Development. / GR2018
108

Investigation of Bond Behaviour Between GFRP Reinforcing Bars and Concrete Containing Seawater

Parvizi, Mehran 10 July 2019 (has links)
There has been a growing concern of water scarcity in recent years as global water shortages are increasing. The concrete industry consumes about 2 billion tons of potable water annually. For this reason, seawater has drawn attention as a potential substitute for mixing and curing water for concrete if certain challenges can be addressed. One of the main problems associated with the use of seawater in concrete is the risk of corrosion of internal steel reinforcement. Fibre-reinforced polymer (FRP) bars have been shown to be a viable reinforcement alternative in aggressive environments due to their corrosion-resistant properties. Glass FRP (GFRP) bars, due to their acceptable mechanical properties and reasonable price, are currently the most widely used in industry. GFRP bars are manufactured with a variety of surface configurations having different bond performance in concrete, which influences structural behaviour in concrete flexural elements. Therefore, the viability of GFRP bars with sand coated and spiral deformations in seawater concrete is an important topic for research. In this study the bond behaviour is investigated using two different test methods: 1) pullout specimens, and 2) beam anchorage specimens. The results suggest that there is no significant difference between the short-term bond strength of GFRP bars in seawater concrete compared to normal concrete. Additional research is recommended to explore possible long-term issues.
109

Measuring Bond Mutual Fund Performance with Portfolio Characteristics

Moneta, Fabio January 2009 (has links)
Thesis advisor: Pierluigi Balduzzi / Employing a novel data set of portfolio weights from 1997 to 2006, the performance of taxable bond mutual funds is studied. The timing ability of fund managers is examined considering different asset allocation choices such as asset class, credit quality allocation, and portfolio maturity decisions. I show that active managers engage in strategies of rotating their portfolios across fixed-income sectors and bond characteristics. Some bond funds exhibit successful timing ability by adopting these strategies. Comparing fund returns plus expenses and transaction costs with the returns of a portfolio that is invested in the previously disclosed holdings, I document that active managers exhibit some ability to select securities that deliver better returns than the securities in the indices. In particular, on average, active managers generate gross returns of 1% per annum over the benchmark portfolio constructed using past holdings. / Thesis (PhD) — Boston College, 2009. / Submitted to: Boston College. Carroll School of Management. / Discipline: Finance.
110

Development of bond strength in hydraulic lime mortared brickwork

Zhou, Zhaoxia January 2012 (has links)
The first recorded use of hydraulic lime in construction can be traced back to at least two thousand years ago. Hydraulic lime, produced through either adding pozzolanic materials or calcining clay containing limestone, unlike air lime, can set and harden under water, developing strength through initial hydration reaction and subsequent carbonation. After WWII Portland cement mortars had almost completely replaced lime based mortars in modern construction. However, through conservation and specialist construction the benefits of hydraulic lime are becoming increasingly recognised. To support wider usage of these mortars there is a need for systematic study on the mortar properties and structural performance of lime mortared masonry. This thesis presents findings from a research programme conducted to develop understanding of the mechanical properties of natural hydraulic lime (NHL) mortared brickwork. The work focussed on the flexural strength of NHL mortared brickwork. A variety of material and environmental factors, including lime grade and supplier, mix proportion, sand type and age, have been investigated. In addition the research has completed an in-depth study on the influence of brick absorption characteristics on bond development. The two methods of flexural wall panel and bond wrench testing to establish flexural strength have been compared. In addition to flexural strength, initial shear strength and compressive strength of brickwork has also been investigated. A greater understanding of NHL mortared brickwork performance has been developed through this work. Performance of the brickwork has been related to properties of constituent materials and environmental factors. Recommendations for design performance of materials have been provided.

Page generated in 0.0465 seconds