Today, it is a very crucial problem that many European countries are encountering demographic challenges stemming from the population decline and aging and according to many studies and future projections, this demographic trend will reach more critical levels for the next 50 years. The most prominent impact of this demographic situation will be on social security systems that the functioning and sustainability of pension and health care systems will be severely damaged with regard to the rapidly increasing number of elderly and the decline in number of young labor force resulting from the low births rates all over Europe. In this context, labor migration that received significant attention, has risen up to the agenda of Europe to serve as a policy option to mitigate the adverse consequences of demographic challenges. Taking its impetus from the mentioned demographic problem, this thesis aims to analyze the discussions over labor migration as a foreseen policy option to compensate the shortage of labor force in Europe. It also intents to bring relevant data and current debates together to generate a ground in order to open this critical issue to discussion and to elaborate the feasibility of labor migration need for Europe. In this regard, the thesis scrutinizes the reactions of European states regarding their reluctance to open their borders again for &ldquo / mass influx&rdquo / and examines briefly the other preferred and enforced policies that exclude migration option, such as aiming to increase fertility rates, ameliorate social security systems or encourage the native labor force participation. By taking all these into account, this thesis aspires to attract attention to this urgent problem and evaluates the labor migration need in Europe by presenting the relevant reactions and appraisals shaping the migration policies both at the nation state and EU level. Finally, this thesis attempts to contribute to the literature in terms of generating a base for further intensified discussions and studies which constitutes a significant need in the context of interaction between demography and migration in Europe.

Background：Aortic stenosis (AS) is the commonest valve disease in the West. Aortic valve replacement (AVR) remains the only available management for AS and results in improved symptoms and recovery of ventricular functions. In addition, it is well known that AVR results in disruption of LV function mainly in the form of reversal of septal motion as well as depression of right ventricular (RV) systolic function. The aim of this thesis was to study, in detail, the early and mid-term response of ventricular function to AVR procedures (surgical and TAVI) as well as post operative patients’ exercise capacity. Methods：We studied LV and RV function by Doppler echocardiography and speckle tracking echocardiography (STE) in the following 4 groups; (1) 30 severe AS patients (age 62±11 years, 19 male) with normal LV ejection fraction (EF) who underwent AVR, (2) 20 severe AS patients (age 79±6 years, 14 male) who underwent TAVI, (3) 30 healthy controls (age 63±11 years, 16 male), (4) 21 healthy controls (age 57±9 years, 14 male) who underwent exercise echocardiography. Results: After one week of TAVI, the septal radial motion and RV tricuspid annulus peak systolic excursion (TAPSE) were not different from before, while surgical AVR had significantly reversed septal radial motion and TAPSE dropped by 70% compared to before. The extent of the reversed septal motion correlated with that of TAPSE (r=0.78, p<0.001) in the patients as a whole after AVR and TAVI (Study I). Compared with controls, the LV twist function was increased in AS patients before and normalized after 6 months of surgical AVR. In controls, the LV twist correlated with LV fractional shortening (r=0.81, p<0.001), a relationship which became weak in patients before (r=0.52, p<0.01) and after AVR (r=0.34, p=ns) (Study II). After 6 months of surgical AVR, the reversed septal radial motion was still significantly lower than before. The septal peak displacement also decreased and its time became prolonged. In contrast, the LV lateral wall peak displacement increased and the time to peak displacement was early. The accentuated lateral wall peak displacement correlated with the septal peak displacement time delay (r=0.60, p<0.001) and septal-lateral time delay (r=0.64, p<0.001) (Study III). In 21 surgical AVR patients who performed exercise echocardiography, the LV function was normal at rest but different from controls with exercise. At peak exercise, oxygen consumption (pVO2) was lower in patients than controls. Although patients could achieve cardiac output (CO) and heart rate (HR) similar to controls at peak exercise, the LV systolic and early diastolic myocardial velocities and strain rate as well as their delta changes were significantly lower than controls. pVO2 correlated with peak exercise LV myocardial function in the patients group only, and the systolic global longitudinal strain rate (GLSRs) at peak exercise was the only independent predictor of pVO2 in multivariate regression analysis (p=0.03) (Study IV). Conclusion: Surgical AVR is an effective treatment for AS patients, but results in reversed septal radial motion and reduced TAPSE. The newly developed TAVI procedure maintains RV function which results in preservation of septal radial motion. In AS, the LV twist function is exaggerated, normalizes after AVR but loses its relationship with basal LV function. While the reversed septal motion results in decreased and delayed septal longitudinal displacement which is compensated for by the accentuated lateral wall displacement and the time early. These patients remain suffering from limited exercise capacity years after AVR.

Surfaces exposed to wear always transform and typically a layer of new structure and composition is formed. This layer, often called tribofilm, changes the friction and wear properties. Tribofilms formed on ceramic surfaces may consist of products from chemical reactions between the materials in contact and the environment or consist of compacted wear debris. In this thesis, focus has been to understand the friction and wear mechanisms of ceramic surfaces, as well as acquiring knowledge about the properties of the new surfaces created during wear. Ultimately, this understanding can be used to develop ceramic systems offering high or low friction, while the material loss in both cases should be minimised. Such ceramics could improve numerous tribological systems and applications, out of which ultrasonic motors, low-friction ceramic coatings and hip joint replacements have been treated in this thesis. Friction and wear tests, and subsequently various surface analyses have been essential for the knowledge about the friction, wear and tribofilm formation.  For ultrasonic motors of the studied type, the highest driving force is achieved when the friction is high between the alumina components in the friction drive system. The highest friction was here accomplished with a thick tribofilm on the surfaces. The formation of such tribofilms was favoured by dry conditions, and using an initially rough surface, which increased the initial generation of wear debris. In a detailed investigation of the importance of microtopography on tribofilm formation and friction behaviour, a low-friction, PVD coating of TaC/a-C was studied. This coating showed a very low, stable friction. High sensitivity to the microtopography was demonstrated, smooth coating exhibited a faster build-up of a dense tribofilm of fine ground material on the counter steel surface and subsequently a faster running in and friction decrease.  The life span for total hip joint replacements can be prolonged by minimising the wear particles that cause inflammation and subsequent implant loosening. In this work coatings of amorphous/nanocrystalline silicon nitride have shown low wear rate, and hence produce a minimum of wear particles. Furthermore, these particles that are expected to resorb in vivo. This system therefore has potential to reduce problems with inflammation and osteolysis connected to wear particles.

Abstract This study examined memory functioning from a female perspective, with the aim of determining factors that might impact performance and render the accuracy of memory measurement, particularly with advancing age, problematic. Factors investigated, among others, were the role of attention and/or engagement with the memory tasks administered, state affect (i.e., positive and negative arousal) at time of testing, subjective memory appraisal, particularly in the domain of perceived memory self-efficacy (MSE), and the use of hormone replacement therapy (HRT) by older post-menopausal women. Two experimental computer-based tests of episodic memory, Paired Associates (PA) and Serial Recall (SR), were administered to 181 female participants aged 18 to 86 years. The tasks were designed to emphasise components that make episodic memory especially difficult, and minimise the use of strategies that might assist recall. Thus, they varied the requirement for recall as opposed to recognition, the need to form an association between a pair of unrelated words, and the need to discriminate the most recent list from earlier list(s). Other measures used included a demographic survey administered to participants individually in an interview format, and a number of variables examined in this study derived from responses to items contained in this survey. The research battery also included psychometric measures of transient affective states, psychological well-being, alertness, in addition to measures of global cognitive status and metamemory (i.e., subjective memory appraisal). The overall aim was to examine a range of factors that might influence episodic memory performance in cognitively intact healthy women, and thus render the interpretation of age-related changes to memory functioning problematic. For analyses participants were assigned to three groups - young, middle-aged and older. There were 60 young adults aged 18 to 29 years, 60 middle-aged adults aged 49 to 60 years, and 61 older adults aged 61 to 86 years. Each participant was tested individually in a single session lasting approximately 3 ½ hours, with younger participants requiring less time to complete assessments. Order of test administration and instructions were standardised across the entire sample. Inferential statistics included correlation, t-test statistic, and analysis of variance (ANOVA) with Tukey post-hoc comparisons. Hierarchical multiple regression analyses were conducted to determine key correlates of memory performance outcomes. No significant differences between the cohorts were found in mean years of education. However, episodic memory recall differed significantly by age group. As expected, young adults recalled significantly more words in the memory tasks than their older counterparts, and middle-aged adults outperformed adults in the oldest cohort. Moreover, older adults’ performance deficits were more pronounced in the tasks requiring that they make an association between a pair of unrelated words. Across all cases, transient mood states were significantly related to memory scores; however, individuals in the oldest cohort were particularly vulnerable to mood fluctuations. This cohort experienced a significantly greater decline in positive affect and a significant greater increase in negative affect while undergoing memory testing, highlighting their greater vulnerability to stressors inherent in a memory testing situation. Although scores on the measure of attention were near ceiling, indicative of participants’ level of effort, motivation, and engagement with the memory tasks, the measure of attention discriminated between older and younger adults’ results, and was a key predictor of memory performance. Noteworthy is that attention scores significantly contributed to performance variability in younger and older adults but not in middle-aged adults. Across all cases, age, education, and attention were the key contributing factors to variability in memory scores. Although four lifestyle factors: (1) subjective sleep appraisal, (2) body mass index (BMI), (3) physical activity, and (4) caffeine intake were significantly associated with performance in the memory tasks, once the effects of these key variables were removed, lifestyle factor did not uniquely contribute to performance variability. Moreover, no association was found between hormone replacement therapy (HRT) and episodic memory performance across the broader sample. However, in a small subgroup of older women (n = 15, M age = 66 years), long-term users of this treatment, HRT had a significant effect on memory performance and was indicative of better recall on the memory tasks. The effect of subjective memory appraisal, MSE included, on objective performance outcomes was examined. The results showed that memory self-evaluations were not a significant contributing factor to episodic memory performance, confirming that memory self-appraisal is a poor predictor of actual memory performance, and thus does not pose a challenge to the measurement of age-related changes to memory abilities. Although there were commonalities, factors influencing memory performance differed by age cohort. For example, in young adults, positive mood, a perception of sleeping well, subjective health, and attention were significantly related to performance on the memory tasks. However, once the effect of attention was removed in the regression analysis, no other variable was predictive of episodic memory functioning in this cohort. In contrast, the single significant predictor of memory performance in middle-aged individuals was education, and neither attention, nor positive mood, or physical activity had a significant effect on this cohort’s performance. Similarly, having more years of formal education benefited older adults’ episodic memory functioning. However, high scores on global cognitive functioning and on the tasks measuring attention were equally important to episodic memory recall in this age group. In sum, the significant contribution of age to memory variability attested to the utility of the memory measures in detecting age-related changes to episodic memory functioning, which were independent of deficits in attention or level of education. Moreover, the effect of several factors (e.g., transient mood, lifestyle) on memory scores was explained by an effect on attention, and this has clear implication for the proper evaluation of long-term changes to memory functioning. Limitations of the study and suggestion for future research are discussed.

Abstract This study examined memory functioning from a female perspective, with the aim of determining factors that might impact performance and render the accuracy of memory measurement, particularly with advancing age, problematic. Factors investigated, among others, were the role of attention and/or engagement with the memory tasks administered, state affect (i.e., positive and negative arousal) at time of testing, subjective memory appraisal, particularly in the domain of perceived memory self-efficacy (MSE), and the use of hormone replacement therapy (HRT) by older post-menopausal women. Two experimental computer-based tests of episodic memory, Paired Associates (PA) and Serial Recall (SR), were administered to 181 female participants aged 18 to 86 years. The tasks were designed to emphasise components that make episodic memory especially difficult, and minimise the use of strategies that might assist recall. Thus, they varied the requirement for recall as opposed to recognition, the need to form an association between a pair of unrelated words, and the need to discriminate the most recent list from earlier list(s). Other measures used included a demographic survey administered to participants individually in an interview format, and a number of variables examined in this study derived from responses to items contained in this survey. The research battery also included psychometric measures of transient affective states, psychological well-being, alertness, in addition to measures of global cognitive status and metamemory (i.e., subjective memory appraisal). The overall aim was to examine a range of factors that might influence episodic memory performance in cognitively intact healthy women, and thus render the interpretation of age-related changes to memory functioning problematic. For analyses participants were assigned to three groups - young, middle-aged and older. There were 60 young adults aged 18 to 29 years, 60 middle-aged adults aged 49 to 60 years, and 61 older adults aged 61 to 86 years. Each participant was tested individually in a single session lasting approximately 3 ½ hours, with younger participants requiring less time to complete assessments. Order of test administration and instructions were standardised across the entire sample. Inferential statistics included correlation, t-test statistic, and analysis of variance (ANOVA) with Tukey post-hoc comparisons. Hierarchical multiple regression analyses were conducted to determine key correlates of memory performance outcomes. No significant differences between the cohorts were found in mean years of education. However, episodic memory recall differed significantly by age group. As expected, young adults recalled significantly more words in the memory tasks than their older counterparts, and middle-aged adults outperformed adults in the oldest cohort. Moreover, older adults’ performance deficits were more pronounced in the tasks requiring that they make an association between a pair of unrelated words. Across all cases, transient mood states were significantly related to memory scores; however, individuals in the oldest cohort were particularly vulnerable to mood fluctuations. This cohort experienced a significantly greater decline in positive affect and a significant greater increase in negative affect while undergoing memory testing, highlighting their greater vulnerability to stressors inherent in a memory testing situation. Although scores on the measure of attention were near ceiling, indicative of participants’ level of effort, motivation, and engagement with the memory tasks, the measure of attention discriminated between older and younger adults’ results, and was a key predictor of memory performance. Noteworthy is that attention scores significantly contributed to performance variability in younger and older adults but not in middle-aged adults. Across all cases, age, education, and attention were the key contributing factors to variability in memory scores. Although four lifestyle factors: (1) subjective sleep appraisal, (2) body mass index (BMI), (3) physical activity, and (4) caffeine intake were significantly associated with performance in the memory tasks, once the effects of these key variables were removed, lifestyle factor did not uniquely contribute to performance variability. Moreover, no association was found between hormone replacement therapy (HRT) and episodic memory performance across the broader sample. However, in a small subgroup of older women (n = 15, M age = 66 years), long-term users of this treatment, HRT had a significant effect on memory performance and was indicative of better recall on the memory tasks. The effect of subjective memory appraisal, MSE included, on objective performance outcomes was examined. The results showed that memory self-evaluations were not a significant contributing factor to episodic memory performance, confirming that memory self-appraisal is a poor predictor of actual memory performance, and thus does not pose a challenge to the measurement of age-related changes to memory abilities. Although there were commonalities, factors influencing memory performance differed by age cohort. For example, in young adults, positive mood, a perception of sleeping well, subjective health, and attention were significantly related to performance on the memory tasks. However, once the effect of attention was removed in the regression analysis, no other variable was predictive of episodic memory functioning in this cohort. In contrast, the single significant predictor of memory performance in middle-aged individuals was education, and neither attention, nor positive mood, or physical activity had a significant effect on this cohort’s performance. Similarly, having more years of formal education benefited older adults’ episodic memory functioning. However, high scores on global cognitive functioning and on the tasks measuring attention were equally important to episodic memory recall in this age group. In sum, the significant contribution of age to memory variability attested to the utility of the memory measures in detecting age-related changes to episodic memory functioning, which were independent of deficits in attention or level of education. Moreover, the effect of several factors (e.g., transient mood, lifestyle) on memory scores was explained by an effect on attention, and this has clear implication for the proper evaluation of long-term changes to memory functioning. Limitations of the study and suggestion for future research are discussed.

Diss. (sammanfattning) Stockholm : Karol. inst., 2004. / Härtill 4 uppsatser.

Thesis (Ph.D. in Epidemiology) -- University of Colorado Denver, 2007. / Typescript. Includes bibliographical references (leaves 100-117). Free to UCD affiliates. Online version available via ProQuest Digital Dissertations;

Ce travail de doctorat se décompose en quatre parties distinctes. La première partie concerne la caractérisation hémodynamique sur simulateur cardiovasculaire de prothèses valvulaires mitrales de différents constructeurs en vue de leur évaluation clinique et du diagnostique de leur dysfonction. La seconde partie se focalise sur les prothèses valvulaires mécaniques bi-clapet au travers desquels le phénomène de recouvrement de pression dû au passage de l'écoulement à travers les trois orifices formés par les clapets peut engendrer une surestimation du gradient transvalvulaire. Ce phénomène peut entrainer une ambiguïté lors de l'évaluation de la prothèse en cas de gradient transvalvulaire important. Cette partie s'attache à quantifier ce phénomène et à évaluer l'influence d'une dysfonction (disproportion patient-prothèse ou obstruction d'un clapet) sur celui-ci. La troisième partie concerne la procédure valve-in-valve dans laquelle une prothèse percutanée est implantée dans une bioprothèse défaillante. Elle fournit une caractérisation in vitro, première au niveau mondial, d'assemblages de la prothèse SAPIEN Edwards dans des bioprothèses issues de différents constructeurs. Enfin et suite à la mise en évidence dans les parties précédentes de profils de vitesse en amont de la prothèse ne pouvant être assimilés à des profils plats, l'étude des patrons de flux auriculaires a été réalisée grâce à des acquisitions in-vitro. / This PhD work is divided into four different parts. the first part concerns the hemodynamic characterization by in-vitro cardiovascular testing of mitral valvular prosthesis from different manufacturers in order to provide reference values for clinical diagnosis. The second part focus on bi leaflet mechanical heart valve in each pressure recovery resulting of flow through the three orifices could lead to an overestimation of transvalvular pressure gradient. This could create ambigious assessment in case of high value of transvalvular pressure gradient. This part aims to quantify this pressure recovery and identify the influence of dysfunction (leaflet obstruction or patient prosthesis mismatch) on this value. Third part consists in valve-in-valve procedure in which a transcatheter valve is impllanted in a failled bioprosthesis. It provides in vitro testing, first globally, of assemblies composed of SAPIEN Edwards prostheses in different manufacturers' bioprosthesis.As highlighted in the previous parts inflows of the mitral prostheses can not be considered as plane and results of left atrium flow patterns. The last part studies the left atrium flow following mitral valve replacement.

Majority of electricity networks have growing number of ageing elements. Critical network components, such as ageing underground cables, are very expensive to install and disruptive to replace. On the other hand, global climate changes have made connection of new low carbon technologies (LCT) into the grids increasingly necessary. These factors are contributing to the increasing complexity of the planning and management of power systems. Numerous techniques published on this subject tend to ignore the impact of LCT integration and the anchoring ꞌSmartꞌ solutions on ageing network assets, such as underground cables and transformers. This thesis presents the development procedures of an ageing underground cable reliability model (IEC-Arrhenius-Weibull model) and cable ranking models for replacement based on system wide effects and thermal loss-of-life metrics. In addition, a new concept of LCT integration and distribution network management was proposed using two optimization models. The first optimizes connection of new wind sources by minimizing the connection cost and the cost of cable thermal loss-of-lives in the planning period. In the second stage, the network is optimally reconfigured in such a way to minimize thermal-loss-of-life of ageing cable. Both optimization models are formulated as mixed integer non-linear programming (MINLP) problems applicable to radially operated medium voltage networks. To quantify the reliability benefits of the proposed approach, Sequential Monte Carlo Simulation (SMCS) procedure was formulated. Some of the main features of the SMCS procedure are the IEC-Arrhenius-Weibull model for ageing cable, optimal network reconfiguration, wind generation modelling using ARMA models and real time thermal ratings. The final outputs are reliability metrics, cable ranking lists for replacement, savings due to 'non-spend' cable thermal lives, etc. These studies have proven to be important in formulating an effective strategy for extending the lives of network cables, managing overall network reliability and planning cables replacement in power distribution networks.

Cette thèse a pour objet d’explorer les situations corporelles en milieu urbain sous le filtre des appareils de prises de vues selon différents angles, échelles et placements. Les mobilités des passants, les tactiques d’évitement, les rythmes pressés des pas, les intersections des trajectoires et la polyphonie qui forment la trame changeante du quotidien de la ville sont scrutés, sondés, capturés et retravaillés par l’opération du montage au sein d’une démarche plasticienne personnelle. En partant d’une expérience vécue du dépaysement au sein de la métropole parisienne, je souhaite examiner les intrications entre la fabrique du regard de l’étrangère et la construction des images vidéographiques et photographiques. Ces intrications se trouvent orchestrées, méthodologiquement, par trois concepts opératoires à géométries variables : le déplacement, l’emplacement et le replacement. Le premier mouvement correspond à l’expérience vécue et immersive de la ville où il sera question de la dimension sensible des pratiques pédestres. Le second se positionne sous l’angle du perçu, interrogeant le regard de l’observateur, de l’enquêteur et le traitement poïétique des matériaux visuels et sonores capturés par les appareils d’enregistrement. Le troisième répond à un changement du régime plastique, où le corps plasticien se dédouble, oscillant entre le filmant et le filmé, faisant du cadre vidéographique une scène performative. Quant au cadre théorique, il est également double. Il s’agit, d’une part, de recueillir en filigrane les leçons de la phénoménologie de Merleau-Ponty, de la microsociologie de Simmel et de l’anthropologie urbaine contemporaine. D’autre part, il s’agit de faire résonner les harmoniques de ma démarche avec des démarches d’artistes issues des années 1960 et 1970, comme les Situationnistes, Valie Export, Vito Acconci ou Esther Ferrer, et d’autres plus contemporains qui sondent les scénographies du corps et ses images, tels qu’Isabelle Grosse, Valérie Jouve, Mark Lewis et Maïder Fortuné. / The objective of this dissertation is to explore the situations of the body in an urban environment as mediated via different angles, scales and positions. A personal artistic démarche of editing records, surveys, and scrutinizes the mobility of passers and bystanders; the result is an audio-visual record that tracks the tactics of evasion, the speedy rhythms of steps, the intersections of the trajectories and the polyphony that form the thread of daily life in the city. Taking as a point of departure my personal experience - a change of scene (déplacement) in the metropolis of Paris - I examine the disorientations between the rendering of the foreigner’s gaze and the construction of videographic and photographic images. From a methodological point of view, three concepts of variable geometry organize these concepts in states of dynamic imbrication: delocation (déplacement), location (emplacement) and relocation (replacement). The first movement, which corresponds to the lived experience of immersion into the city, treats the sense-based dimension of pedestrian practices. The second, which concerns perception, interrogates the gaze of the observer and of the investigator and of the poetic treatment of taped visual and sonic material. The third concept entails a change of the plastic regime where the artistic body is divided in two: oscillating between the filming and the filmed where ultimately the videographic scene becomes a performative scene. The theoretical framework is likewise divided in two. On the one hand, it is inspired by Merleau-Ponty’s phenomenology, by Simmel’s microsociology and by contemporary urban anthropology. On the other hand, it consists of an evidencing of resonances between my own démarche and those of artists active in the 1960s and 1970s like the Situationists, Valie Export, Vito Aconci or Esther Ferrer, as well as more contemporaries like Isabelle Grosse, Valérie Jouve, Mark Lewis and Maïder Fortuné, who scrutinize the scenographies of the body and of its images.