To date, the most common pharmacological treatments for dementia are cholinesterase inhibitors and N-methyl-D-aspartate receptor antagonists (antidementia medications), which are associated with a delay in the progression of the cognitive and functional symptoms. Studies of the effects of antidementia medications on neuropsychological symptoms (NPS) show varying results. Presence of NPS can also affect the amount of time caregivers spend with persons with dementia, which can affect informal costs of the condition. This project used extant data from the longitudinal, population-based Cache County Study on Memory and Aging (CCSMA) and the Dementia Progression Study (DPS), which included permanent residents aged ≥ 65 of Cache County, Utah. Linear mixed models were used to assess the association between antidementia medications with informal costs and NPS. The first study examined whether antidementia medications were associated with a decrease in informal costs. Use of antidementia medications was not significantly associated with informal costs (expβ = .79, p = .090). When restricting the sample to only the participants who were of mild dementia severity at baseline, antidementia medications were associated with a 28% decrease in informal costs (expβ = .72, p = .039). The second study evaluated whether antidementia medications were associated with a decrease in NPS. Results indicated that use of antidementia medications was associated with a 28% increase in NPS (expβ = 1.28, p < .001). However, this association was no longer significant with the inclusion of covariates, in particular, the use of psychotropic medications. Use of any psychotropic medication was significantly associated with a 30% increase in Neuropsychiatric Inventory (NPI) score. Overall, the use of antidementia medications may not significantly reduce informal costs or NPS. The use of antidementia medications may reflect patterns of use that are prompted by severity of dementia and NPS.

This dissertation examines the emergence of ethnic parties, their survival in the political system, and their impact on the governance practices. While scholars have long debated the impact of ethnic parties on state-building and democratization process, few works have empirically examined their behavior in the political system. Empirical research on ethnic parties is limited to single countries or regions -- Latin America, Eastern Europe, or a few countries including India. Firstly, this dissertation extends the research on ethnic parties to include another South Asian Country – Nepal. Secondly, research on ethnic parties has been hampered by the lack of cross-sectional data on ethnic parties. This dissertation employs new datasets on the electoral performance of ethnic parties, making use of the newly available resource. Employing both qualitative and quantitative techniques, this dissertation is built around three empirical chapters. Firstly, it argues that strategic interactions between major parties and ethnic groups, among others, determine why some ethnic groups successfully form their own parties and others do not. Secondly, it argues that the factors that are responsible for the emergence of ethnic parties are hardly sufficient for the survival of these parties in the long run and shows that ethnic parties' access to state resources is a major factor that can explain the variation in their survival. And thirdly, it argues and empirically shows that support from ethnic groups to political parties does not necessarily lead to higher levels of corruption as scholars have often argued. The parties that are overwhelmingly supported by ethnic groups increase the level of regime corruption, while the parties that have large coalitions of voters including ethnic groups do not.

HIV/AIDS is a global pandemic with critical demographic, economic, and social implications. The pandemic is widespread in poor regions of the world, including Southeast Asia where its long-term effects are potentially catastrophic. Despite the major impacts of the epidemic being already felt at the household level in many countries, a lack of recognition of the socioeconomic determinants of HIV infection and the economic and social impacts of HIV/AIDS and their relationship with poverty persists. This is due in part to the lack of systematic studies at the household, community, sectoral, and macro levels. The thesis describes a 'vicious circle' between HIV/AIDS, poverty and high-risk behaviour at the individual level. In the poverty-HIV/AIDS cycle, HIV-infected individuals are especially vulnerable to poverty, the poor are more likely to engage in high-risk behaviour such as commercial sex work, and high-risk behaviour in turn makes people susceptible to HIV infection. The thesis examines whether rural Northeast Thailand exhibits characteristics that support the existence of such a cycle. Four key relationships are considered and tested: (i) the relationship between previous HIV infection and current wealth or poverty; (ii) the relationship betweem wealth or poverty and HIV/AIDS knowledge; (iii) the relationship between previous wealth or poverty and current HIV infection; and (iv) the relationship between previous migration and current HIV infection. All four relationships are shown to hold using survey data from Khon Kaen province in Northeast Thailand. Poverty is shown to increase susceptibility to HIV infection, and HIV/AIDS is shown to reduce wealth and hence increase poverty. Under the circumstances, the hypothesis that rural Northeast Thailand exhibits characteristics that would suggest the existence of a poverty-HIV/AIDS cycle cannot be rejected. This thesis also provides several key contributions to the literature on HIV/AIDS and poverty. First, it provides quantitative and qualitative empirical analysis of the impacts of HIV/AIDS on households in a moderately affected region of Thailand. Second, it provides empirical analysis both on whether wealth and poverty affect the risk of HIV infection, and whether HIV infection affects wealth and poverty. The results from this thesis also provide significant empirical evidence of the importance of rural-urban migration in the spread of HIV in Asia. Finally, the thesis investigates the potential effects on the poverty-HIV/AIDS cycle of an ongoing socio-economic intervention, namely breaking the poverty-HIV/AIDS cycle via intensive rural development.

Sea-bed benthic-invertebrate assemblages of species within and proximal to an existing mussel farm off Taniwhanui Point, eastern Waiheke Island, are reported. Substratum type, whether predominantly mud, gravels or an admixture of the two, mud/gravels, is shown to influence infaunal species assemblage composition; the bivalve Theora lubrica, ostracods, amphipods and polychaetes characterise muddy substrata; polychaetes, particularly spionids and syllids, ostracods, amphipods, bivalves and ophiuroids characterise mud/gravel substrata; and diverse assemblages of polychaetes, bivalves, pagurid crabs, gastropods, ostracods, ophiuroids and nemertean worms characterise gravel substrata. Significant differences in sea-bed assemblages are reported along one transect inside and outside the farm over the three seasons during which surveys were conducted, summer, autumn, winter of 2008. Along the northern side of the mussel farm those sediments beneath the farm are characterised by greater abundances of polychaetes and crustaceans (Malacostraca), whereas sediments outside the farm are characterised by greater abundances of bivalves and ostracods. Sediments both inside and outside the north-eastern border of the farm during summer are characterised by similar abundances of polychaetes, bivalves and ostracods. Similarly, those sediments within and outside the farm along its southern border during summer are characterised by abundances of polychaetes, bivalves, crustaceans (Malacostraca) and gastropods. Measures of relative abundance, rarity and species richness are applied to sea-bed assemblages off eastern Waiheke Island to enable an appraisal of the spatial distribution of each within and outside the farm, and throughout the eastern Waiheke Island region. One of these measures, relative abundance, is then compared with other, albeit limited abundance data from previous soft-sediment surveys conducted throughout Hauraki Gulf. The most species rich and abundant sites off eastern Waiheke Island occur in gravelly substrata between Waiheke Island and Pakatoa Island, and between Rotoroa and Ponui Islands, in addition to beneath the southern portion of the existing mussel farm. Gravel-based substrata are recognised to be the most species rich and densely populated with invertebrates for this sediment type in Hauraki Gulf. Similarly, the muddy substrata off eastern Waiheke Island region appear to host more individuals and species than any other reported muddy substratum in Hauraki Gulf. The existing mussel farm is shown to significantly affect sea-bed communities, but in a manner that has not been previously reported in New Zealand. Species richness and abundance are greater beneath the farm, as are the proportions of very rare and uncommon taxa to more common and ubiquitous taxa. Sediments beneath the farm are not characterised by elevated abundances and richness of opportunistic species; and no obvious difference in sediment grain size is apparent along a transect extending from 20 m inside the farm to at least 110 m outside it. The biological footprint of the farm is limited, appearing to extend no further than 20 metres from the northern physical boundary of the farm; the gross sedimentary characteristics (grain size) do not differ significantly within and outside the farm. Within and immediately outside the farm species richness and abundance tend to increase during colder seasons; beneath the farm, species richness (d), abundance (N), Shannon index (H’) and Simpson index (1-λ’) were higher during May (autumn) and August (winter) than during February (summer); diversity values outside the farm were similar during summer and autumn, but species richness (d), evenness (J’), Shannon index (H’) and Simpson index (1-λ’) were all greater during winter. No opportunistic taxa are considered to be appropriate indicators of organically enriched environments, at least enrichment that can be intuitively linked to any direct effect of the existing mussel farm. One species, the heart urchin Echinocardium cordatum, only rarely occurs inside the physical farm boundary, so its relative abundance renders it an appropriate indicator species of mussel-farm impacts.

Life Cycle Assessment (LCA) has been successfully used as an environmental assessment tool for the development of ecologically sustainable products. The application of LCA in the early design stage has been constrained by the requirement of large amounts of data and time for carrying out the assessment. In addition, the complexity of LCA causes further difficulties for product developers. In order to integrate the environmental assessment into the process of product development, this research proposes an integrated decision model for sustainable product development and a simplified LCA approach for the application in the early stage of product design. The main advantage of the proposed model is that it incorporates the environmental aspects of product development into the existing product development framework. It enables designers to strike a balance between the product???s environmental performance and other traditional design objectives. The simplified LCA approach is based on the concept and application of Environmental Impact Drivers. Material-based environmental impacts and Energy-based environmental impacts are used to predict the total environmental impact of a product. Two sets of impact drivers were developed accordingly. The Material-based Impact Drivers were identified by classifying materials into 16 groups according to the nature of the materials and their environmental performance. Energy-based Impact Drivers were developed for various energy sources in major industrial regions. Product LCA cases were used to verify the proposed methods. The results computed by the application of the impact drivers were compared with the results of full LCA studies. It is concluded that with the proposed approach, the product???s environmental performance can be assessed in a very short time and with very basic data input requirements and acceptable accuracy.

This thesis details an investigation into the properties and applications of shape memory alloy (SMA) composites. SMA-composites are a new material which have the possibility of having a large impact on what the structures as we know today, are constructed with. SMA-composites are adaptive materials which can be used to control the shape and frequencies of vibration of a structure. In order to determine the effectiveness of such a material, research into the functional properties of SMAs and SMA-composites was conducted. As an initial step, the transformation behaviour of constrained SMAs was investigated in order to obtain a better understanding into the recovery stress generation of these wires when embedded into a composite material. It is known that the transformation is based on two types of martensite within the alloy; self accommodating and preferentially oriented martensite. The amounts of each type and how they vary with differing pre-strain were determined through DSC measurements and an explanation for why preferentially oriented martensite is not observed during DSC testing was made. The next step was to investigate the effectiveness of embedding SMA wires into composites and the thermomechanical properties of the SMA wires and the SMA-composites were determined. This was completed using a specially designed tensile testing machine which was capable of having the whole specimen immersed into an oil bath and heated and cooled repeatedly. The stress-strain, strain-temperature, stress-temperature, resistance-strain and cyclic properties of various wires were obtained, giving a better understanding of the behaviour of SMA wires under different test conditions. NiTiCu SMA wires were embedded into kevlar composite materials and the recovery stress generation (stress-temperature), stress-strain, and strain-temperature behaviour was determined. If SMA-composites are to be used as new materials for structural applications, verification that the embedment of pre-strained SMA wires into the material doesn't adversely affect the impact behaviour needs to be carried out. SMA-composite specimens with varying volume fractions of superelastic SMA wires, pre-strain and position through the thickness were made up for impact damage characterisation. These specimens were impacted at three different energy levels. The results showed that by embedding SMA wires into composite materials there is a reasonably low damage accumulation after impact. There is also no adverse impact effect on the structure compared with structures without wires as well as structures with other types of wires such as steel and martensitic SMA wires. The SMA-composites showed good damping and energy absorption capabilities. A novel application of SMA-composites is their use as a SMA patch in order to repair damage in existing cracked metallic structures. An analytical study and finite element modelling showing the closure stresses obtainable for use as patches was made.

Environmental impact assessment (EIA) was introduced to inform decision-makers of the potential environmental effects of the decision before them. It has been adopted worldwide and functions as one of the primary instruments for taking account of environmental consequences in project approval decision-making. To date, there has been very little systematic investigation that explores whether the decision-makers for whom the EIA information is produced actually use it, although there are indications that EIA information is not always effective in influencing decisions. This thesis examines how, and indeed if, environmental effects information influences the decision-making processes for which it is produced, and which factors determine the use of this information. Three main areas of concern are identified and investigated: the responses of individual decision-makers to environmental effects information; the characteristics of the effects information that influence these responses; and the processes by which the effects information is dealt with. At the core of the methodology employed for this research is the development of an exploratory model of EIA-based decision-making. This model builds on the insights into decision processes from a variety of disciplines, including psychology and planning. To test the utility of the model, it is evaluated against the New Zealand system of resource consent approval decision-making under the Resource Management Act, by means of case studies. Through interviews, direct observation, and analysis of written documents the decision processes in these cases are analysed. These techniques have been augmented by psychosocial methods that allow further probing into the decision processes that takes place in a decision-maker�s head. The research results show that the effort that is spent on the preparation of EIA reports and the improvement of EIA processes is not wasted. The EIA information clearly influences the decision processes for which it is intended but it is not influencing decisions optimally. EIA information often competes with information on environmental effects from other sources that is of higher quality, more credible, or better tailored to the decision-makers� information needs. A number of ways in which the use of EIA information could be enhanced is explored in this thesis. Foremost, the improvement of the effectiveness of EIA requires a wider adoption of a decision-making perspective on EIA, and a broader recognition of the information needs of the different decision processes for which EIA is prepared.

The next generation of European scientific satellites will carry extremely sensitive measurement devices that require platform stability orders of magnitude higher than current missions. It is considered that the meteoroid and space debris (M/SD) environment poses a risk to the success of these missions as disturbances induced by the impact of these particles at hypervelocity may degrade the platform stability below operational requirements. In this thesis, disturbances induced by the impact of M/SD particles at hypervelocity on a representative scientific satellite platform have been investigated. An extensive experimental impact test program has been performed, from which an empirical ballistic limit equation (BLE) which defines the conditions of structural perforation for composite sandwich panel structures with CFRP facesheets and aluminium honeycomb cores (CFRP/Al HC SP) has been defined. The BLE is used to predict impact conditions capable of inducing the different excitation modes relevant for a SP sandwich panel structure, enabling a significant reduction in the time and expense usually required for calibrating the protective capability of a new structural configuration. As experimental acceleration facilities are unable to cover the complete range of possible in-orbit impact conditions relevant for M/SD impact risk assessment, a Hydrocode model of the representative CFRP/Al HC SP has been constructed. A series of impact simulations have been performed during which the local impact-induced disturbance has been measured. The numerical disturbance signals have been validated via comparison with experimental disturbance measurements, and subsequently subject to a characterisation campaign to define the local elastic excitation of the SP structure equivalent to that induced by impact of a M/SD particle at hypervelocity. The disturbance characterisation is made such that it is applicable as an excitation force on a global satellite Finite Element (FE) model, allowing propagation of impact-induced disturbances throughout the complete satellite body to regions of critical stability (i.e. measurement devices). The disturbance induced upon measurement devices by M/SD impacts at both near- and far-body locations can then be made, allowing the threat to mission objectives to be assessed.

L'objectif de ce mémoire est de faire une présentation synthétique des activités de recherche que j'ai menées au sein du LMT Cachan depuis neuf ans et de mettre en avant le fil conducteur du travail réalisé. Ce travail est la synthèse de collaborations avec différents chercheurs, industriels, doctorants et stagiaires de M2.Trois thèmes principaux seront développés ici. Ils concernent, comme le titre du mémoire l'indique, la modélisation mécanique et numérique de structures soumises à un impact. Afin de pouvoir proposer des méthodes prédictives de dimensionnement, je me suis attaché à aborder les trois éléments de bases : la modélisation du matériau, l'expérimentation sur structures et la modélisation numérique. En plus de ma notice individuelle, ce document présente donc les principaux résultats obtenus dans chacune des trois thématiques suivantes : Développement de lois de comportement adaptées à la dynamique Calculs sur structures industrielles Caractérisation expérimentale Pour chacun de ces trois thèmes, les motivations du travail et les principaux apports sont présentés en compléments de la copie d'un article représentatif des activités menées. La première partie est consacrée au premier thème de recherche développé, à savoir la modélisation du comportement des matériaux, tout particulièrement le béton, soumis à des sollicitations dynamiques. Je présenterai dans celui-ci un bref rappel du modèle développé lors de ma thèse de doctorat et qui a servi de base de travail pour une thèse que j'ai co-encadrée. Dans un deuxième temps, je présenterai un modèle d'endommagement anisotrope qui a fait l'objet de nombreux développements et publications ces dernières années. Enfin, je finirai par présenter un modèle utilisé pour les matériaux composites et que j'ai été amené à utiliser. Le seconde chapitre vise à présenter mes principales contributions concernant le développement de méthodes multiéchelles pour la représentation des matériaux et/ou de structures sous chargement sévère. Ainsi, je commencerai par présenter une approche ou le matériau n'est plus considéré comme homogène mais constitué d'une matrice et d'inclusions plus ou moins rigides. Ensuite je m'attarderai un peu plus sur deux méthodes numériques développées pour la modélisation de structure. Ces deux méthodes sont le fruit de mon passage dans le secteur ''Structures et Systèmes'' du LMT Cachan pendant 4 ans. Ceci m'a permis d'étoffer le champs de mes connaissances dans les matériaux composites et dans la méthode LATIN développée au laboratoire. La troisième partie est liée au développement d'outils de calcul prédictifs pour les problèmes d'impact. C'est pourquoi je commencerai par présenter des essais sur tour de chute que nous avons développés en collaboration avec le CEA Saclay. Ces essais nous ont ensuite été utiles pour montrer les capacités de prédictions des différentes modélisations développées. Ceci a été confirmé par la simulation d'essais de souffle et d'impact de réacteur d'avion sur des dalles en béton armé réalisés dans les années 90. Finalement, quelques perspectives sur mes activités de recherche sont proposées à la fin de ce document. Cette dernière partie présente notamment les activités de recherche et d'encadrement qui débute cette année. L'annexe correspond à mon dossier professionnel. Il contient, en plus de mon CV, mon implication dans divers contrats de recherche, mes activités d'encadrement, ainsi que la liste de mes publications scientifiques.

<p>Impact waves are used in many different industries and are classified according to whether they cause plastic or elastic deformations. In the plastic deformation mode, these waves can be used to produce special electrical joints. In the elastic deformation mode, they can be used to detect leakage or to measure the thickness of pipes. Both modes have applications in offshore technology. In this thesis the application of impact waves in the plastic deformation mode and explosive welding are discussed. In the explosive welding (EXW) process a high velocity oblique impact produced by a carefully controlled explosion occurs between two or more metals. The high velocity impact causes the metals to behave like fluids temporarily and weld together. This process occurs in a short time with a high rate of energy.</p><p>EXW is a well known method for joining different metals together. It is a multidisciplinary research area and covers a wide range of science and technology areas including wave theory, fluid dynamics, materials science, manufacturing and modeling. Many of the important results in EXW research are obtained from experimentation.</p><p>This thesis is mainly based on experimental work. However, it begins with a review of the fundamental theory and mechanisms of explosive welding and the different steps of a successful welding operation. Many different EXW tests are done on horizontal and vertical surfaces with unequal surface areas, and on curved surfaces and pipes. The remainder of the thesis evaluates the results of these experiments, measures the main parameters, and shows the results of simulations to verify the experimental results. The thesis ends with a number of suggestions for improving and optimizing the EXW process. One of these improvements is a model for joining metallic plates with unequal surface areas. An Al-Cu joint based on this model is used in the ALMAHDI aluminum factory, a large company in southern Iran that produces more than 200,000 tons of aluminum per year. Improved methods are also suggested for joining curved surfaces. These methods may have extensive applications in pipelines in oil and gas industries, especially in underwater pipes.</p> / <p>Impact vågor används i många olika branscher och klassificeras enligt de deformationer de orsakat: elastiska och plastiska deformationer. I plastisk deformation mode, dessa vågor skulle kunna användas för att framställa särskild elektrisk lederna. I deformationen läge, de skulle kunna användas för att upptäcka läckage eller mäta tjockleken på rören. Båda har tillämpningar inom offshore-teknik. I denna avhandling tillämpningen av effekterna vågor i plastisk deformation mode och explosiva svetsning diskuteras. I den explosiva svetsning (EXW) process hög hastighet sned effekt som produceras av en noggrant kontrollerad explosion uppstår mellan två eller flera metaller. Den höga hastigheten effekt gör att metaller gå ihop samtidigt som beter sig som vätskor. Denna process sker i en kort tid med hög energi.</p><p>EXW är en känd metod för att gå med olika metaller tillsammans. Det är ett tvärvetenskapligt forskningsområde och omfattar ett brett spektrum av naturvetenskap och teknik, inklusive våg teori, vätskor dynamik, materialvetenskap, tillverkning och modellering. Många av de viktiga resultat i EXW forskning har erhållits från experiment.</p><p>Denna uppsats bygger främst på experimentella verk. Det kommer dock att börja med en genomgång av grundläggande teori och mekanism av explosiva svetsning och de olika stegen i en lyckad welding operation. Då många olika EXW tester göras på horisontella och vertikala ytor med icke lika ytor och på krökta ytor och ledningar. Utvärdering av resultaten, som mäter de viktigaste parametrarna, som utför vissa simuleringar för att verifiera experimentella resultat och några förslag för att förbättra och optimera EXW process utgör de andra delarna av uppsatsen. En av dessa förbättringar är en modell för att gå med metalliska plattor med icke-lika ytor. En Al-Cu gemensamt bygger på denna modell används i ALMAHDI aluminium fabrik, ett stort företag i södra Iran att produktionen är mer än 200000 ton per år. Dessutom en del andra förbättrade metoder föreslås för att gå med krökta ytor. Dessa metoder kan få omfattande tillämpningar inom olje-och gasindustrin som rörledningar, särskilt under rören.</p>