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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.
261

Social Exclusion and The Sense of Agency

Malik, Rubina January 2019 (has links)
This thesis explored the effects of social exclusion on the sense of control. We indexed the sense of control using the sense of agency. The sense of agency refers to the feeling of control over our actions and the outcomes of those actions. We experience the sense of agency at an implicit, pre-reflective level. In other words, we routinely make movements that impact some sort of change in the environment, and simply just know that our actions cause an effect. Experimentally, we can measure the sense of agency using the intentional binding effect. Intentional binding is a temporal illusion in which we perceive the time between our voluntary action and the outcome of that action to be shorted compared to when the same effect is caused by an involuntary action. We conducted three experiments. In experiment one, we used an episodic memory recall task to prime participants to feel socially excluded or socially included. In experiment two, we used a different manipulation of social exclusion and social inclusion called Cyberball. We found that in both experiments, intentional binding was significantly reduced following social exclusion compared to social inclusion and baseline. In experiment three, we investigated the pre-reflective sense of agency in eating disorders. Eating disorders are highly associated with chronic social exclusion experiences and an altered sense of control in life. We found that individuals with higher eating disorder symptomatology experience a lower sense of agency, compared to healthy individuals. Overall, this thesis is the first to demonstrate that social exclusion has observable effects on the sense of agency. We were able to triangulate these findings using another social exclusion manipulation as well, strengthening our original findings. Lastly, we showed that a disorder characterized, in part, by social exclusion, reduces the sense of agency / Thesis / Master of Science (MSc)
262

Unga kvinnors upplevelser av att leva och växa upp med föräldrar från två helt skilda kulturer

Al Harbiti, Nesrin, Sindy, Sofia January 2022 (has links)
Dubbel kulturtillhörighet kan vara både positivt och negativt. Tidigare forskning visade att tillhörighetskänslan är grundläggande för ens identitesskapande. Undersökningens syfte var att öka förståelsen för hur kvinnor upplever att deras identitet påverkas av att växa upp med föräldrar från två skilda kulturer - en svensk och en utländsk - och vilka kulturella skillnader man behövt hantera under uppväxten. Semistrukturerade intervjuer genomfördes med 13 kvinnor i åldrarna 18-30. Analysen av identitetspåverkan genererade teman som att hamna i utan- eller mellanförskap, att anpassa sig utifrån omgivning och kontext och möjlighet till ökad förståelse och brett perspektiv. Kulturella skillnader kunde tematiseras som normer och värderingar, individualism vs. kollektivism, och krav och förväntningar. Resultatet visade bland annat på ett upplevt utan- eller mellanförskap, men även en ökad förståelse. Slutsatsen var att unga kvinnors identitet påverkades av att växa upp med två skilda kulturer med grund i flera olika aspekter som värderingar, krav och förväntningar.
263

Guidance, policy and practice and the health needs of young people leaving care.

Goddard, James A., Barrett, S. January 2008 (has links)
No / During the past ten years, there has been growing interest in the health needs of young people leaving care in England and Wales. Most such young people leave care between the ages of 16 and 18 and many experience significant problems adjusting to independent living. This article fulfils two objectives. First, it examines the legislative and policy context within which practice towards such young people is now conducted. Second, it deepens our understanding of this policy context by reporting the results of a project on this subject that was undertaken in one local authority district in the north of England in 2005. The project surveyed all young care leavers within the district, analysing their health concerns and experiences. Using postal questionnaires (70 responses), face-to-face interviews (30) and focus groups (two), it sought to provide a clear picture of current needs and to inform future policy action by local health and social care professionals.
264

The Inequality of Social Capital and the Reproduction of Chronic Poverty.

Cleaver, Frances D. 21 October 2009 (has links)
No / This paper draws on ethnographic research in Tanzania to question ideas inherent to mainstream development policy that building social capital can be readily created, used, or substituted for other missing assets, and thereby overcome poverty. The poorest experience clusters of interlocking disadvantage that make it highly unlikely that they can draw on social capital to ameliorate their poverty, or that increased association and participation at community level is necessarily beneficial to them. Moreover, social relationships, collective action, and local institutions may structurally reproduce the exclusion of the poorest. As such, a politically neutral and undersocialized policy focus on strengthening associational life and public participation of the poor is unlikely to lead to their greater inclusion, nor to significant poverty alleviation.
265

What's the problem with teenage parents? And what's the problem with policy?

Duncan, Simon January 2007 (has links)
No / Public discourse in Britain sees teenage motherhood as a pernicious social problem where mothers, their children and society generally will all suffer. Fathers are seen as feckless. This is reflected in New Labour's teenage pregnancy strategy, which understands teenage parents as victims of ignorance, mis-information, and low expectations. But a review of the research evidence finds that the age at which pregnancy occurs has little effect on social outcomes. Many teenage mothers describe how motherhood makes them feel stronger, and marks a change for the better. Many fathers seek to remain connected with their children. For both, parenting seems to provide an impetus to take up education, training and employment. Teenage parenting may be more of an opportunity than a catastrophe, and often makes sense in the life worlds inhabited by young mothers. The paper ends by asking how we can explain this yawning gulf between the experience of teenage parenting and policy, and concludes that this largely rests on assumptions of rational choice, in turn creating a `rationality mistake'.
266

Leveraging Epistemic Exclusion as a Lens for Investigating Black Engineering Students' Undergraduate Research Experiences

Brisbane, Julia Machele 04 June 2024 (has links)
Undergraduate research experiences (UREs) are presented as a mechanism for improving the persistence of Black engineering students. However, because most engineering UREs are led by faculty and staff in Colleges of Engineering, it is reasonable to assume they are not immune to the systemic racial issues that plague engineering education. Existing scholarship on epistemic exclusion theorizes that individual biases and institutional practices contribute to faculty of color's scholarship being devalued and deemed illegitimate, but this topic is underexplored in UREs. LSAMP is an NSF-funded program that provides funding for institutions to create UREs for racially minoritized students in STEM, providing a ripe context for exploring the phenomenon of epistemic exclusion in UREs. This explanatory mixed methods study examines facets of epistemic exclusion prevalent in the undergraduate research experiences of Black engineering LSAMP scholars and the practices undergirding it. The findings of this study are based on survey and interview data collected from current and former LSAMP scholars. The survey results reveal perceptions of low levels of epistemic exclusion via scholarly devaluation; and there were no significant differences in survey responses based on race, gender, or whether in an engineering discipline or not. However, the qualitative phase helped explain the quantitative results. Black engineering students, specifically, experienced epistemic exclusion in ways that differ from literature on underrepresented faculty; and they perceived UREs as an opportunity for learning knowledge – not producing it. While positive peer interactions and a welcoming lab enabled epistemic inclusion, a toxic lab culture and inadequate URE program structures enabled epistemic exclusion. These findings have implications for faculty mentors, URE program administrators, policymakers, and education researchers. They are valuable for advancing our understanding of Black engineering students participating in UREs, contributing to national efforts to broaden participation of racially minoritized students in engineering education, and diversifying the research enterprise and the engineering workforce. / Doctor of Philosophy / Undergraduate research experiences (UREs) are presented as a means of improving Black engineering students' persistence. However, since most engineering UREs are led by faculty and staff in Colleges of Engineering, it is reasonable to assume they are not immune to the systemic racial problems occurring in engineering education. Existing scholarship on epistemic exclusion suggests that individual biases and institutional practices contribute to faculty of color's scholarship being devalued and considered illegitimate, yet this issue is underexplored in UREs. LSAMP is an NSF-funded program that provides funding for institutions to create UREs for racially minoritized students in STEM, offering an opportunity to explore the phenomenon of epistemic exclusion in UREs. This explanatory mixed methods study examines forms of epistemic exclusion prevalent in the undergraduate research experiences of Black engineering LSAMP scholars and the practices undergirding it. The findings of this study are based on survey and interview data collected from current and former LSAMP scholars. The survey results reveal feelings of low levels of epistemic exclusion through scholarly devaluation; and there were no significant differences in survey responses based on race, gender, or whether in an engineering field or not. However, the qualitative phase helped explain the quantitative results. Black engineering students, particularly, experienced epistemic exclusion in ways that differ from literature on underrepresented faculty; and they observed UREs as an opportunity for learning knowledge – not producing it. While positive peer interactions and a welcome lab enabled epistemic inclusion, a toxic lab culture and inadequate URE program structures allowed epistemic exclusion. These findings may be beneficial for faculty mentors, URE program administrators, policymakers, and education researchers. They are valuable for advancing our understanding of Black engineering students taking part in UREs, contributing to national efforts to broaden participation of racially minoritized students in engineering education, and diversifying the research enterprise and the engineering workforce.
267

Synthesis, Molecular Weight Characterization and Structure-Property Relationships of Ammonium Ionenes

Borgerding, Erika Michelle 27 November 2007 (has links)
Ammonium ionenes are macromolecules with quaternized nitrogen groups in the main chain. Ionenes are commonly referred to as x,y-ionene, where x and y represent the number of methylene groups between quaternized nitrogens. Synthesis of aliphatic ammonium ionenes has been studied since the early twentieth century; however, absolute molecular weight characterization has only been performed using extensive light scattering and viscosity experiments. Performing aqueous size exclusion chromatography (SEC) on ammonium ionenes provides absolute molecular weight determinations while eliminating the need for separate viscosity and light scattering experiments. We developed a mobile phase composition that provides reliable separation of aliphatic ammonium ionenes using aqueous SEC. For the first time, we report absolute molecular weights of aliphatic ammonium ionenes using this technique. We investigated the influence of charge density and structural symmetry on thermal and mechanical properties of ammonium 6,6-, 12,6- and 12,12-ionenes. Thermal properties were measured using differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA), and mechanical properties were measured using dynamic mechanical analysis (DMA) and an Instron. Incorporating low molecular weight polymer segments into the main chain of the ionene allows tailoring of polymer characteristics. Poly (tetramethylene oxide) segments decrease hydrophilicity and increase elastomeric character. Linear PTMO based ionenes have been synthesized previously, and we were interested in how branching affected thermal and mechanical properties. We synthesized bis(dimethylamino) poly(tetramethylene oxide) segments, and subsequently, synthesized linear and branched ionenes to study the effects of topology on thermal and mechanical properties. Polymers were analyzed using DMA, DSC, TGA, SAXS, and an Instron. / Master of Science
268

Mechanisms for Enhancing Spectrum Utilization in a Spectrum Access System

Ullah, Abid 07 March 2017 (has links)
Multi-antenna systems with resource allocation based on transmit and receive precoding matrices have proven to enhance the spectral efficiency of cellular systems. In this thesis, we extend these concepts to a spectrum sharing system with primary users and secondary users. The spectrum sharing area is modeled as an array of transmit and receive antennas, with the transmit power constraint defined as a function of the interference threshold of the primary user. The area covered by a database enabled spectrum access system is represented as spatial bins, which are regions of predefined sizes. Each bin is assumed to have a single secondary user base station and all the resources of that bin (i.e., available frequencies, transmit power, etc.) are consumed by this secondary user in that bin. With these assumptions, the service area of the database can be represented by a grid of secondary users. Such a grid of secondary users forms a array of transmit antennas with secondary users in each bin. Furthermore, the set of bins with its secondary users at the edge of the exclusion zone of the primary user are assumed to create an array of receive antennas. These receive antennas act as sensors that will measure the interference power at the edge of the exclusion zone of the primary users. So the overall system of secondary user base station transmit and receive antennas can be modeled as a multi-element antenna array system. A regulatory interference threshold (I<sub>th</sub>) is defined for protection of the primary user at the edge of exclusion zones. This interference threshold is used by the resource allocation algorithms in the spectrum access system to calculate the transmit and receive precoding matrices for the secondary user antenna array. Using multiple-input multiple-output theory, the receive antenna array will measure the interference from the transmit antenna array and a feedback mechanism will update the resource allocation to keep the power at the receive array below the interference threshold of the primary user. For each array, the transmit/receive matrix is a beamforming vector which consists of a set of weights, one for each antenna. Furthermore, a codebook-based strategy is used by the spectrum access system database to choose a transmit matrix from the codebook which minimizes the interference at the primary user. The overall spectrum sharing system can be represented by a model based on four design parameters, namely, Δ = (I<sub>th</sub>, P, V, B), where P is the transmit power constraint, V are the transmit and receive beamforming matrices, and B is the matrix with active secondary user base stations of the antenna array or the quality of service level of the secondary users. The Δ parameter is called the system index of the spectrum sharing system. We apply the multi-antenna model to the challenging problem of spectrum sharing where the primary users operational parameters, such as transmit power levels, waveform types, and service modes, can change with time. Moreover, there are several types of primary users in different bands. Most of these users are federal government systems and their operational parameters are not available to the spectrum access system database. Our framework is useful in sharing spectrum with federal primary users, since only the interference threshold is needed for sharing their bands. Furthermore, we quantify the uncertainty in the availability of these bands for secondary users and the variations in achievable capacity with sharing spectrum in these bands. / Ph. D. / The goal of this thesis is to build a Protected Shared Access Model (PSAM) through database enabled Spectrum Access System (SAS). A model for the SAS is proposed, which is based on our vision for the SAS as a more dynamic and responsive architecture as a geolocation database than the current TVWS database. Major functions and capabilities of the model include, calculations of exclusion zone (EZ) of primary users with different operational parameters, use interference estimation techniques for predicting interference levels that will be generated by the new secondary users (SUs) and existing systems operating in the database service area, allocate location based transmit power levels and provide an algorithm for communications among the PUs, SUs, and the SAS to implement management and authorization framework of spectrum resources to different types of SUs. The selection of a propagation model is of utmost importance in spectrum sharing studies. Existing literature on EZs with simplified propagation models does not consider the effect of LOS interference between the PU to SU link and SU to PU link on peak points in the terrain area around the PU. The use of a terrain profile based model captures the essence of propagation over irregular terrain. Terrain regions that are far away from the PU may have a LOS between the PU and SU. So its not only the nearest area where the PU/SU can get interference, but interference is present from areas further away on high grounds having a direct LOS with the PU antenna. The exclusion zone computation with terrain profile based propagation model captures this effect, and it is the same effect that makes the shape of the exclusion zone irregular. So the propagation model used in spectrum sharing studies must be able to use the terrain for the specific geographical area for precise propagation calculations, and provide statistical reliability parameters for the computed propagation values for area of interest. For a multi-tier shared access model with incumbent access (IA) users, priority access (PA) users and general authorized access (GAA) users. The SU interference tolerance thresholds varies by the type of SU's i-e., PA users like public safety systems and mission critical users have low tolerance for interference and hence need to operate further from the PU. While GAA users like commercial broadband systems have higher interference tolerances and can operate closer to the PU. This multi-tier shared access model requires varying levels of interference protection from PU, that can be provided with multiple exclusion zones defined for different types of SU's. We propose the concept of differential spectrum access hierarchy, and define it in the context of a multi-tiered EZs that are based on quantiles of tolerable interference levels for different tiers of SUs. We also quantify and show the gain in SU capacity (or throughput) obtained by using multi-tiered EZs for different tiers of SUs. Using simulation results, we show that the size of EZs can be significantly reduced with the use of a terrain profile-based propagation model that takes into account terrain profile for signal attenuation between PUs and SUs in the P2P link. The exclusion zones involve the use of interference test points at the circumference of the protection contour of the PU. They are monitoring test points that the SAS uses with a propagation model and locations of SUs to calculate interference. Consider a model of Figure 5.1, the coexistence environment with PU, SU and the SAS with a database. As more SUs enter the system, their transmit powers creates interference for the PUs. In the event of SU interference exceeding a predefined threshold level at any of the test points, the SAS uses an interference based power control algorithm to turnoff the nearest dominant interferer's. Turning off the dominant interferers eliminates interference generated by that node at the PU. This nearest node interference cancellation significantly reduces the outage probability at the PU. Unlike existing metrics for spectrum utilization efficiency that considers separate metrics for PU interference protection and maximum use of the band for secondary use, we define a new metric for spectrum utilization efficiency. This metric uses utility functions and cost functions to measure the impact of secondary use of the spectrum on PUs as well as the degree of satisfaction SUs can achieve from reuse of such spectrum. The new spectrum utilization metric is used to evaluate tradeoffs between interference protection of PUs and SU spectrum utilization.
269

Analysis Using Size Exclusion Chromatography of poly(N-isopropyl acrylamide) using Methanol as an Eluent

Swift, Thomas, Hoskins, Richard, Telford, Richard, Plenderleith, R.A., Pownall, David, Rimmer, Stephen 25 May 2017 (has links)
Yes / Size Exclusion Chromatography is traditionally carried out in either aqueous or non-polar solvents. A system to present molar mass distributions of polymers using methanol as a mobile phase is presented. This is shown to be a suitable system for determining the molar mass distributions poly(N-isopropylacrylamide)s (PNIPAM); a polymer class that is often difficult to analyze by size exclusion chromatography. DOSY NMR was used to provide intrinsic viscosity data that was used in conjunction with a viscometric detector to provide absolute calibration. Then the utility of the system was shown by providing the absolute molar mass distributions of dispersed highly branched PNIPAM with biologically functional end groups. / Wellcome Trust
270

Comprendre la performance des algorithmes d'exclusion mutuelle sur les machines multicoeurs modernes / Understanding the performance of mutual exclusion algorithms on modern multicore machines

Guiroux, Hugo 17 December 2018 (has links)
Une multitude d'algorithmes d'exclusion mutuelle ont été conçus au cours des vingt cinq dernières années, dans le but d'améliorer les performances liées à l'exécution de sections critiques et aux verrous.Malheureusement, il n'existe actuellement pas d'étude générale et complète au sujet du comportement de ces algorithmes d'exclusion mutuelle sur des applications réalistes (par opposition à des applications synthétiques) qui considère plusieurs métriques de performances, telles que l'efficacité énergétique ou la latence.Dans cette thèse, nous effectuons une analyse pragmatique des mécanismes d'exclusion mutuelle, dans le but de proposer aux développeurs logiciels assez d'informations pour leur permettre de concevoir et/ou d'utiliser des mécanismes rapides, qui passent à l'échelle et efficaces énergétiquement.Premièrement, nous effectuons une étude de performances de 28 algorithmes d'exclusion mutuelle faisant partie de l'état de l'art, en considérant 40 applications et quatre machines multicœurs différentes.Nous considérons non seulement le débit (la métrique de performance traditionnellement considérée), mais aussi l'efficacité énergétique et la latence, deux facteurs qui deviennent de plus en plus importants.Deuxièmement, nous présentons une analyse en profondeur de nos résultats.Plus particulièrement, nous décrivons neufs problèmes de performance liés aux verrous et proposons six recommandations aidant les développeurs logiciels dans le choix d'un algorithme d'exclusion mutuelle, se basant sur les caractéristiques de leur application ainsi que les propriétés des différents algorithmes.A partir de notre analyse détaillée, nous faisons plusieurs observations relatives à l'interaction des verrous et des applications, dont plusieurs d'entre elles sont à notre connaissance originales:(i) les applications sollicitent fortement les primitives lock/unlock mais aussi l'ensemble des primitives de synchronisation liées à l'exclusion mutuelle (ex. trylocks, variables de conditions),(ii) l'empreinte mémoire d'un verrou peut directement impacter les performances de l'application,(iii) pour beaucoup d'applications, l'interaction entre les verrous et l'ordonnanceur du système d'exploitation est un facteur primordial de performance,(iv) la latence d'acquisition d'un verrou a un impact très variable sur la latence d'une application,(v) aucun verrou n'est systématiquement le meilleur,(vi) choisir le meilleur verrou est difficile, et(vii) l'efficacité énergétique et le débit vont de pair dans le contexte des algorithmes d'exclusion mutuelle.Ces découvertes mettent en avant le fait que la synchronisation à base de verrou ne se résume pas seulement à la simple interface "lock - unlock".En conséquence, ces résultats appellent à plus de recherche dans le but de concevoir des algorithmes d'exclusion mutuelle avec une empreinte mémoire faible, adaptatifs et qui implémentent l'ensemble des primitives de synchronisation liées à l'exclusion mutuelle.De plus, ces algorithmes ne doivent pas seulement avoir de bonnes performances d'un point de vue du débit, mais aussi considérer la latence ainsi que l'efficacité énergétique. / A plethora of optimized mutual exclusion lock algorithms have been designed over the past 25 years to mitigate performance bottlenecks related to critical sections and synchronization.Unfortunately, there is currently no broad study of the behavior of these optimized lock algorithms on realistic applications that consider different performance metrics, such as energy efficiency and tail latency.In this thesis, we perform a thorough and practical analysis, with the goal of providing software developers with enough information to achieve fast, scalable and energy-efficient synchronization in their systems.First, we provide a performance study of 28 state-of-the-art mutex lock algorithms, on 40 applications, and four different multicore machines.We not only consider throughput (traditionally the main performance metric), but also energy efficiency and tail latency, which are becoming increasingly important.Second, we present an in-depth analysis in which we summarize our findings for all the studied applications.In particular, we describe nine different lock-related performance bottlenecks, and propose six guidelines helping software developers with their choice of a lock algorithm according to the different lock properties and the application characteristics.From our detailed analysis, we make a number of observations regarding locking algorithms and application behaviors, several of which have not been previously discovered:(i) applications not only stress the lock/unlock interface, but also the full locking API (e.g., trylocks, condition variables),(ii) the memory footprint of a lock can directly affect the application performance,(iii) for many applications, the interaction between locks and scheduling is an important application performance factor,(iv) lock tail latencies may or may not affect application tail latency,(v) no single lock is systematically the best,(vi) choosing the best lock is difficult (as it depends on many factors such as the workload and the machine), and(vii) energy efficiency and throughput go hand in hand in the context of lock algorithms.These findings highlight that locking involves more considerations than the simple "lock - unlock" interface and call for further research on designing low-memory footprint adaptive locks that fully and efficiently support the full lock interface, and consider all performance metrics.

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