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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.
51

Unprecedented Mechanical Properties in Linear Ultrahigh Molecular Weight Polyethylene via Heterogeneous Catalytic Systems

Gote, Ravindra P. 07 1900 (has links)
Regardless of the simplicity in molecular structure, polyethylene is used in high-performance applications such as medical prostheses and ballistics. Recent advancements in homogeneous catalysis produced UHMWPE in the low-entangled or dis-entangled state that allowed solvent-free-solid-state processing to achieve ultimate mechanical properties ever achieved for a synthetic polymer. Although several homogeneous complexes are known to produce dis-UHMWPE, existing major challenges are uncontrolled nascent polymer morphology, as a consequence reactor fouling/wall sheeting. In such a scenario, a heterogeneous catalyst that can produce dis-UHWMPE to an extent that the characteristics and properties equivalent to that obtained in homogeneous condition, remains an open challenge. The thesis will discuss the know-how for the synthesis of dis-UHMWPE via heterogeneous route to facilitate industrial production by following fundamental understanding of polymerization catalysis, physics, processing, and testing. In this thesis, in-situ formed nano activator/support MgClx/EtnAly(2-ethyl-1-hexoxide)z is employed with a highly active bis[N-(3-tert-butylsalicylidene)pentafluoroanilinato] titanium (IV) dichloride (Cat. 1) for synthesis of dis-UHMWPE. In addition, the relatively easy formation of the MgClx/RnClmAly(OR’) activators/supports allows tailoring by the selection of different aluminum-alkyls and alcohols, giving access to a variety of co-catalysts. This investigation resulted in UHMWPE having Mw from 3 to an unprecedented 43 M g/mol and Ð from 3 to 38 with very high activities up to 2750 kgPE molcat.-1 bar-1 h-1. The adopted route resulted in nano-support that allows tailoring of the entangled state and control over the nascent morphology without reactor fouling, thus providing feasibility of pursuing the polymerization via a continuous process. The nascent polymer shows formation of single crystals of linear UHMWPE and is suggestive of the low-entangled state. The topological differences, with the commercial entangled sample, are identified solid-state NMR, DSC, and rheology. The disentangled crystals allowed desired chain orientation for securing unprecedented tensile modulus (>200 N/tex) and tensile strength (>4.0 N/tex) via solid-state processing. Additionally, the investigation of creep response in the uniaxial tapes has revealed strong influence of molecular weight and entanglement density. These unique characteristics and unprecedented mechanical properties are equivalent to that perceived using a homogeneous catalysis and are the first of their kind achieved for a polymer synthesized using a heterogeneous catalysis.
52

Prisoners of war: formations of masculinities in Vietnam war fiction and film

Boyle, Brenda Marie 17 October 2003 (has links)
No description available.
53

Gender and Citizenship in the Constitution of Nepal, 2015

Dhamala, Roshani 03 July 2019 (has links)
This research project explores the consequences of the citizenship provision of Nepal, as reflected in Nepal's most recent constitution promulgated in 2015, for the Nepalese citizens as well as the Nepalese society and culture in general. This project employs two methods of data collection: close reading of the citizenship provision and ethnographic interviews of those Nepalese who are directly affected by the provision. Results are drawn through rhetorical and textual analysis of the collected data. The results show that the current citizenship provision disempowers women of Nepal by stopping them from passing on their citizenship to their children. The citizenship provision is also a source of humiliation for such women and the reason behind the condition of stateless-ness of millions of people living in Nepal. On a cultural level, this citizenship provision both reflects and re-enforces patriarchy in Nepal. / Master of Arts / This research project explores the consequences of the citizenship provision of Nepal as reflected in Nepal's most recent constitution promulgated in 2015 for the Nepalese citizens as well as the Nepalese society and culture in general. This project employs two methods of data collection: close reading of the citizenship provision and ethnographic interviews of those Nepalese who are directly affected by the provision. Results are drawn through rhetorical and textual analysis of the collected data. The results show that the current citizenship provision disempowers women of Nepal by stopping them from passing on their citizenship to their children. The citizenship provision is also a source of humiliation for these women and the cause of stateless-ness of millions of people in Nepal. On a cultural level, this citizenship provision both reflects and reenforces patriarchy in Nepal.
54

Peruvian Food Insecurity in The Face of Recurrent Natural Disasters: A Two-Step Adoption Analysis for Improved Potato Varieties

O'Donnell, Catherine Elizabeth 02 February 2018 (has links)
The International Potato Center (CIP) and Peruvian National Agricultural Research Institute (INIA) have invested a substantial amount of resources towards the development of improved potato varieties in Peru. These varieties are adaptable to the agro-ecologies of the Andes and have specific biotic and abiotic attributes. These efforts have led to the release of several prominent varieties including Canchan-INIA, Amarilis, Unica, Serranita and others. A 2013 household survey conducted by CIP was used to describe the diffusion of improved potato varieties in Peru. These data were also used to identify specific constraints to their adoption and dis-adoption. The assessment focused on a two-step adoption model, adoption and dis-adoption, by utilizing a Heckman Probit model to demonstrate two-steps of the adoption process. The Heckman Probit model was used to analyze variables affecting adoption and dis-adoption of improved varieties. Results suggest that adoption is region specific, time dependent, and in some cases relies on informal transmission methods. Risk to food insecurity and recurrent natural phenomena affect adoption and sometimes dis-adoption. Additionally, factors affecting a farmer's exposure to risk, such as information constraints and household head age, wealth, and social network were found to affect the adoption and dis-adoption of improved varieties. / Master of Science / Improved potato varieties, engineered by the International Potato Center (CIP) and Peruvian National Agricultural Research Institute (INIA), are adapted to the agro-ecologies of the Andes and have specific biotic and abiotic attributes, such as late blight resistance. There are a number of prominent engineered varieties produced by CIP and INIA including Canchan-INIA, Amarilis, Unica, Serranita and others, which have the potential to increase the yields and incomes of highland potato farmers. A 2013 household survey conducted by CIP was used to describe the diffusion of improved potato varieties in Peru. These data were also used to identify specific constraints to their adoption and dis-adoption. The assessment focused on a two-step adoption model, adoption and dis-adoption, by utilizing a Heckman Probit model to demonstrate two-steps of the adoption process. The model was used to analyze variables affecting adoption and dis-adoption of improved varieties. Results suggest that adoption is region specific, time dependent, and in some cases relies on informal transmission methods. Farmers living in areas more prone to food insecurity and natural phenomena are less likely to adopt certain improved varieties and more likely to continue to adopt these varieties after initial adoption. Additionally, factors affecting a farmer’s exposure to risk, such as information constraints and household head age, wealth, and social network were found to affect the adoption and dis-adoption of improved varieties.
55

Dissolução de comprimidos e péletes de liberação prolongada empregando-se os métodos da pá e Bio-Dis / Dissolution of tablets and pellets of prolonged release using the methods of the blade and Bio-Dis

Pezzini, Bianca Ramos 13 April 2007 (has links)
Matrizes hidrofílicas de diclofenaco sódico e de cetoprofeno foram preparadas por meio de compressão direta ou granulação úmida seguida de compressão, utilizando-se hipromelose para modular a dissolução do fármaco. Foram também obtidos péletes de liberação prolongada de cetoprofeno, mediante extrusão-esferonização e revestimento, em leito fluidizado, com Kollicoat® EMM 30D. Um planejamento fatorial 22 foi usado para elucidar os efeitos de variáveis de formulação sobre os perfis de liberação do fármaco a partir dos sistemas em estudo, determinados empregando-se os métodos da pá e/ou Bio-Dis. No caso dos comprimidos matriciais, os efeitos do grau de viscosidade e concentração de hipromelose foram investigados. Para os péletes, avaliou-se os efeitos da granulometria e ganho de peso em revestimento. A influência do pH sobre a liberação do fármaco a partir dos sistemas preparados foi também estudada, usando-se meios de dissolução com pH 1,2-7,2. Os métodos ANOVA e teste de Tukey (comparação estatística entre porcentuais de fármaco dissolvido e/ou eficiência de dissolução), f1, f2 e Weibull foram usados para caracterizar e comparar os perfis de dissolução. O grau de viscosidade e concentração de hipromelose influenciaram a liberação de diclofenaco sádico e cetoprofeno a partir das matrizes em estudo, sendo a concentração do polímero o fator principal que governou o processo. A granulação alterou os perfis de dissolução de cetoprofeno em relação às matrizes obtidas por compressão direta, diminuindo a velocidade e modificando o mecanismo de liberação. No caso dos péletes, o ganho de peso em revestimento foi o parâmetro que exerceu maior efeito sobre a liberação do cetoprofeno, enquanto a granulometria apenas influenciou os perfis de dissolução dás formulações com maior ganho de peso em revestimento. A liberação do fármaco a partir dos sistemas em estudo aumentou com a elevação do pH, o que ocorreu devido à solubilidade pH-dependente do cetoprofeno e diclofenaco sódico. / Diclofenac sodium and ketoprofen hydrophilic matrices were prepared by direct compression or wet granulation followed by compression, using hypromellose to modulate the drug dissolution. Sustained release ketoprofen pellets were also obtained by extrusion-spheronization and fluidized bed coating with Kollicoat® EMM 30D. A 22 factorial design has been used to elucidate the effects of formulation variables on the drug release profiles from the systems in study, determined using the paddle method and Bio-Dis. In the case of matrix tablets, the effects of the viscosity grade and concentration of hypromellose were investigated. For the pellets, the effects of granulometry and weight gain were evaluated. The influence of the pH value on the drug release from the prepared systems was also studied, using pH 1,2-7,2 dissolution media. ANOVA and Tukey\'s test (statistical comparison between percentages of drug dissolved and/or dissolution efficiency), f1, f2 and Weibull methods were used to characterize and compare the dissolution profiles. The concentration and viscosity grade of hypromellose influenced the ketoprofen and diclofenac sodium release from the studied matrices, being the polymer concentration the main factor that has governed the process. Granulation has modified the dissolution profiles of ketoprofen in relation to the matrices obtained by direct compression, reducing the rate and modifying the mechanism of drug release. In the pellets case, weight gain was the main factor that has influenced the ketoprofen release, while ganulometry has only influenced the dissolution profiles of the formulation with the highest weight gain. Drug release from the systems under study increased with the increase of the pH value of the medium because of the diclofenac sodium and ketoprofen pH-dependent solubility.
56

Dissolução de comprimidos e péletes de liberação prolongada empregando-se os métodos da pá e Bio-Dis / Dissolution of tablets and pellets of prolonged release using the methods of the blade and Bio-Dis

Bianca Ramos Pezzini 13 April 2007 (has links)
Matrizes hidrofílicas de diclofenaco sódico e de cetoprofeno foram preparadas por meio de compressão direta ou granulação úmida seguida de compressão, utilizando-se hipromelose para modular a dissolução do fármaco. Foram também obtidos péletes de liberação prolongada de cetoprofeno, mediante extrusão-esferonização e revestimento, em leito fluidizado, com Kollicoat® EMM 30D. Um planejamento fatorial 22 foi usado para elucidar os efeitos de variáveis de formulação sobre os perfis de liberação do fármaco a partir dos sistemas em estudo, determinados empregando-se os métodos da pá e/ou Bio-Dis. No caso dos comprimidos matriciais, os efeitos do grau de viscosidade e concentração de hipromelose foram investigados. Para os péletes, avaliou-se os efeitos da granulometria e ganho de peso em revestimento. A influência do pH sobre a liberação do fármaco a partir dos sistemas preparados foi também estudada, usando-se meios de dissolução com pH 1,2-7,2. Os métodos ANOVA e teste de Tukey (comparação estatística entre porcentuais de fármaco dissolvido e/ou eficiência de dissolução), f1, f2 e Weibull foram usados para caracterizar e comparar os perfis de dissolução. O grau de viscosidade e concentração de hipromelose influenciaram a liberação de diclofenaco sádico e cetoprofeno a partir das matrizes em estudo, sendo a concentração do polímero o fator principal que governou o processo. A granulação alterou os perfis de dissolução de cetoprofeno em relação às matrizes obtidas por compressão direta, diminuindo a velocidade e modificando o mecanismo de liberação. No caso dos péletes, o ganho de peso em revestimento foi o parâmetro que exerceu maior efeito sobre a liberação do cetoprofeno, enquanto a granulometria apenas influenciou os perfis de dissolução dás formulações com maior ganho de peso em revestimento. A liberação do fármaco a partir dos sistemas em estudo aumentou com a elevação do pH, o que ocorreu devido à solubilidade pH-dependente do cetoprofeno e diclofenaco sódico. / Diclofenac sodium and ketoprofen hydrophilic matrices were prepared by direct compression or wet granulation followed by compression, using hypromellose to modulate the drug dissolution. Sustained release ketoprofen pellets were also obtained by extrusion-spheronization and fluidized bed coating with Kollicoat® EMM 30D. A 22 factorial design has been used to elucidate the effects of formulation variables on the drug release profiles from the systems in study, determined using the paddle method and Bio-Dis. In the case of matrix tablets, the effects of the viscosity grade and concentration of hypromellose were investigated. For the pellets, the effects of granulometry and weight gain were evaluated. The influence of the pH value on the drug release from the prepared systems was also studied, using pH 1,2-7,2 dissolution media. ANOVA and Tukey\'s test (statistical comparison between percentages of drug dissolved and/or dissolution efficiency), f1, f2 and Weibull methods were used to characterize and compare the dissolution profiles. The concentration and viscosity grade of hypromellose influenced the ketoprofen and diclofenac sodium release from the studied matrices, being the polymer concentration the main factor that has governed the process. Granulation has modified the dissolution profiles of ketoprofen in relation to the matrices obtained by direct compression, reducing the rate and modifying the mechanism of drug release. In the pellets case, weight gain was the main factor that has influenced the ketoprofen release, while ganulometry has only influenced the dissolution profiles of the formulation with the highest weight gain. Drug release from the systems under study increased with the increase of the pH value of the medium because of the diclofenac sodium and ketoprofen pH-dependent solubility.
57

Studium činnosti mikrobiálních MDR-pump pomocí fluorescenčních sond: stanovení účinku potenciálních inhibitorů / Study of the performance of microbial MDR pumps by fluorescent probes: effect of potential inhibitors

Kodedová, Marie January 2011 (has links)
The current increased use of antifungal agents has resulted in the development of resistance to these drugs. Search for new antifungals with different mechanisms of action overcoming the multidrug resistance is thus underway. Surface-active antifungals have the advantages of minimizing host toxicity and the emergence of drug resistance. We have developed a fluorescence method based on the use of the potentiometric fluorescent probe diS-C3(3), substrate of two major S. cerevisiae MDR pumps, Pdr5p and Snq2p. It allows us to monitor with high sensitivity and in real time changes in the activities of both pumps and also in membrane potential. We present here an efficient strategy for identifying pump inhibitors with minimal side effects on membrane integrity, and compare the potencies of different inhibitors towards MDR pumps. New efficient inhibitors of MDR pumps could potentially be used in conjunction with current antimicrobials that are MDR pump substrates. The method can be also used to determine the mechanism of action of surface-active drugs and their lowest effective concentrations.
58

Kuvande rum : Materialitet och funktionsfullkomlighet i berättelser från kvinnor uppväxta på institutioner för barn med normbrytande funktionalitet under 1930 till 1970-talet

Bylund, Christine (Kristin) January 2016 (has links)
Ranging from the late 1880s to the late 1970s children with dis/abilities were orderlyinstitutionalized in Sweden due to lack of accessibility and aids in the surrounding society. The aim of this thesis is to discuss how ableist discourse of dis/ability and gender interacted with materiality, such as buildings, clothes and objects, in the institutions and how it affected the everyday lives of women who grew up there, a concept previously unexplored in a Swedish context. Using a qualitative method interviews were carried out with women who grew up in various institutions in Sweden from the 1930s to 1970s. The interviews were analysed using a crip theoretical understanding of dis/ability and ableism paired with Barad’s post humanist understanding of matter as both product of and producer of discourse. The analysis show that matter was created, used and understood in a constant intra-action with ableist discourse, confining, controlling and subduing the women. Matter and the use of it functioned as a tool for upholding ableism, creating a colonial structure of medical access to the children’s bodies. Hence, the use of matter can be understood as acts of ableist rhetoric created to signalize and uphold ableist standards. Such ableist rhetoric can be said to carry on into the contemporary Swedish understanding of dis/ability, making evident the on-going objectification and medicalization of people with dis/ability today and its intersection with discourses of gender and sexuality.
59

What factors can be identified as the cause of disempowerment and empowerment in Palestine? : A descriptive analysis using Friedmann’s (dis)empowerment model.

Nilsson, Lars January 2015 (has links)
The purpose of this study was to identify and analyze cause of disempowerment for the population of Palestine. The design of the research took the shape of a descriptive case study and the method used to fulfill the purpose was a qualitative text analysis. The material used for the study derives from various books and research journals on the Israeli-Palestine conflict, but most of all observational reports from international organizations. The theory used is a multi-dimensional one and is Friedmann’s (dis)empowerment model where five mechanisms; defensible life space, surplus time, knowledge and skills, instruments of work and livelihood and financial resources have been used as the analytical framework. The conclusion of the study is that there are several factors causing disempowerment following the analysis or the theoretical mechanisms respectively. These are connected to armed hostilities between Israel and Gaza, settlement expansions in the West Bank and the occupational status of Palestine. Supported by the material analyzed, these infringements need to cease combined with exterior help in order for the situation to markedly improve.
60

The determinants of UK Equity Risk Premium

Chandorkar, Pankaj Avinash 10 1900 (has links)
Equity Risk Premium (ERP) is the cornerstone in Financial Economics. It is a basic requirement in stock valuation, evaluation of portfolio performance and asset allocation. For the last decades, several studies have attempted to investigate the relationship between macroeconomic drivers of ERP. In this work, I empirically investigate the macroeconomic determinants of UK ERP. For this I parsimoniously cover a large body of literature stemming from ERP puzzle. I motivate the empirical investigation based on three mutually exclusive theoretical lenses. The thesis is organised in the journal paper format. In the first paper I review the literature on ERP over the past twenty-eight years. In particular, the aim of the paper is three fold. First, to review the methods and techniques, proposed by the literature to estimate ERP. Second, to review the literature that attempts to resolve the ERP puzzle, first coined by Mehra and Prescott (1985), by exploring five different types of modifications to the standard utility framework. And third, to review the literature that investigates and develops relationship between ERP and various macroeconomic and market factors in domestic and international context. I find that ERP puzzle is still a puzzle, within the universe of standard power utility framework and Consumption Capital Asset Pricing Model, a conclusion which is in line with Kocherlakota (1996) and Mehra (2003). In the second paper, I investigate the impact of structural monetary policy shocks on ex-post ERP. More specifically, the aim of this paper is to investigate the whether the response of UK ERP is different to the structural monetary policy shocks, before and after the implementation of Quantitative Easing in the UK. I find that monetary policy shocks negatively affect the ERP at aggregate level. However, at the sectoral level, the magnitude of the response is heterogeneous. Further, monetary policy shocks have a significant negative (positive) impact on the ERP before (after) the implementation of Quantitative Easing (QE). The empirical evidence provided in the paper sheds light on the equity market’s asymmetric response to the Bank of England’s monetary policy before and after the monetary stimulus. In the third paper I examine the impact of aggregate and disaggregate consumption shocks on the ex-post ERP of various FTSE indices and the 25 Fama-French style value-weighted portfolios, constructed on the basis of size and book-to-market characteristics. I extract consumption shocks using Structural Vector Autoregression (SVAR) and investigate its time-series and cross-sectional implications for ERP in the UK. These structural consumption shocks represent deviation of agent’s actual consumption path from its theoretically expected path. Aggregate consumption shocks seem to explain significant time variation in the ERP. At disaggregated level, when the actual consumption is less than expected, the ERP rises. Durable and Semi-durable consumption shocks have a greater impact on the ERP than non-durable consumption shocks. In the fourth and final paper I investigate the impact of short and long term market implied volatility on the UK ERP. I also examine the pricing implications of innovations to short and long term implied market volatility in the cross-section of stocks returns. I find that both the short and the long term implied volatility have significant negative impact on the aggregate ERP, while at sectoral level the impact is heterogeneous. I find both short and long term volatility is priced negatively indicating that (i) investors care both short and long term market implied volatility (ii) investors are ready to pay for insurance against these risks.

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