400 research outputs found
Can a Leopard Change His Spots?: Child Custody and Battererâs Intervention
Enabling multiple base stations to utilize the spatial dimension in a coordinated manner has been shown to be a fruitful technique for improving the spectral efficiency in wireless interference networks. This thesis considers multicell systems where base stations and mobile stations are equipped with multiple antennas. The base stations coordinate their spatial precoding, but individually serve their mobile stations with data. For such coordinated precoding systems, interference alignment (IA) is a useful theoretical tool, due to its ability to serve the maximum number of interference-free data streams. Three topics related to interference alignment and coordinated precoding are studied. First, the feasibility of IA over a joint space-frequency signal space is studied. A necessary condition for space-frequency IA feasibility is derived, and the possible gain over space-only IA is analyzed. An upper bound on the degree of freedom gain is shown to increase in the number of subcarriers, but decrease in the number of antennas. Numerical studies, using synthetically generated channels and real-world channels obtained from indoors and outdoors channel measurements, are used for sum rate performance evaluation. The results show that although a degree of freedom gain is noticeable due to the space-frequency precoding, the sum rate of the system is mainly improved due to a power gain. Second, distributed channel state information (CSI) acquisition techniques are proposed, which provide estimates of the information necessary to perform distributed coordinated precoding. The methods are based on pilot-assisted channel estimation in the uplink and downlink, and correspond to different tradeoffs between feedback and signaling, backhaul use, and computational complexity. Naively applying the existing WMMSE algorithm for distributed coordinated precoding together with the estimated CSI however results in poor performance. A robustification of the algorithm is therefore proposed, relying on the well known diagonal loading technique. An inherent property of the WMMSE solutions is derived and, when enforced onto solutions with imperfect CSI, results in diagonally loaded receive filters. Numerical simulations show the effectiveness of the proposed robustification. Further, the proposed robustified and distributed WMMSE algorithm performs well compared to existing state-of-the-art robust WMMSE algorithms. In contrast to our approach, the existing methods however rely on centralized CSI acquisition. Third, coordinated precoding systems with hardware impairments are studied. Assuming that impairment compensation techniques have been applied, a model is used to describe the aggregate effect of the residual hardware impairments. An iterative resource allocation method accounting for the residual hardware impairments is derived, based on an existing resource allocation framework. Numerical simulations show that the proposed method outperforms all benchmarks. In particular, the gain over impairments-aware time-division multiple access is substantial.Genom att lÄta flera radiobasstationer samarbeta Àr det möjligt att förbÀttra spektraleffektiviteten i trÄdlösa interferensnÀtverk. Fokus i denna licentiatavhandling ligger pÄ multicellnÀtverk dÀr bÄde radiobasstationer och mobilenheter har flera antenner. Radiobasstationerna vÀljer sina spatiella förkodare gemensamt, men skickar data individuellt till sina respektive mobilenheter. För sÄdana system med koordinerad förkodning ('coordinated precoding') Àr interferensupprÀtning ('interference alignment') ett anvÀndbart teoretiskt verktyg, eftersom det möjliggör överföring av maximalt antal dataströmmar i nÀtverket. I avhandlingen studeras tre aspekter av interferensupprÀtning och koordinerad förkodning. Först undersöks interferensupprÀtning nÀr signalrummet bestÄr av en kombination av rymd- och frekvensdimensioner. Ett nödvÀndigt villkor hÀrleds för existensen av rymd/frekvens-interferensupprÀtning, och prestandavinsten analyseras i jÀmförelse med system dÀr enbart rymddimensionerna anvÀnds för interferensupprÀtning. Det föreslagna systemet utvÀrderas med hjÀlp av numeriska simuleringar och uppmÀtta inomhus- och utomhuskanaler. Resultaten visar att rymd/frekvens-interferensupprÀtning ger upphov till ett ökat antal frihetsgrader, men att summadatatakten frÀmst förbÀttras tack vare en upplevd effektförstÀrkning. DÀrefter undersöks tekniker för skattning av den nödvÀndiga kanalkÀnnedom som krÀvs för att genomföra koordinerad förkodning. Det finns flera sÀtt att erhÄlla den nödvÀndiga informationen, t.ex. genom olika kombinationer av kanalskattning, feedback, signalering och anvÀndning av backhaulnÀtverk. Speciellt söks distribuerade metoder, eftersom dessa Àr fördelaktiga vid praktisk implementering. Tre metoder för skattning av kanalkÀnnedom föreslÄs. Dessa motsvarar olika avvÀgningar mellan kanalskattning och signalering, och en av metoderna Àr helt distribuerad. NÀr den skattade informationen anvÀnds med en existerande algoritm för koordinerad förkodning blir prestandan undermÄlig. DÀrför föreslÄs tvÄ förÀndringar av algoritmen, vilka leder till mer robusta prestanda. FörÀndringarna bygger pÄ den vÀlkÀnda diagonal loading-tekniken. UtvÀrdering av det föreslagna systemet, som bestÄr av distribuerad erhÄllning av kanalkÀnnedom samt den förbÀttrade algoritmen för koordinerad förkodning, genomförs med numerisk simulering. Resulterande prestanda Àr i nivÄ med ett tidigare föreslaget system, som dock krÀver centraliserad tillgÄng till kanalskattningarna, till skillnad frÄn vÄr nya lösning. Slutligen studeras ett system med koordinerad förkodning och icke-perfekt radiohÄrdvara. En modell för distortionsbruset orsakad av bristerna i radiohÄrdvaran anvÀnds, och en iterativ resurstilldelningsteknik föreslÄs baserad pÄ ett existerande ramverk. Den föreslagna algoritmen kan implementeras distribuerat över mobilenheterna, men kan i allmÀnhet inte implementeras distribuerat över radiobasstationerna. Den föreslagna algoritmen utvÀrderas med numeriska simuleringar, och resultaten visar att prestanda Àr bÀttre Àn alla referensmetoder. Detta visar betydelsen av att hantera bristerna i radiohÄrdvaran i resurstilldelningen. Sammantaget visar avhandlingen pÄ möjligheterna att öka spektraleffektiviteten i framtida multicellnÀtverk med hjÀlp av koordinerad förkodning.QC 20140512</p
Understanding tensions and identifying clinician agreement on improvements to early-stage chronic kidney disease monitoring in primary care : a qualitative study
Funding This article presents independent research funded by the National Institute for Health Research School for Primary Care Research (NIHR SPCR) (reference:120). JE was also supported by the NIHR Programme Grants for Applied Research programme (Reference: RP-PG-1210-12012). DSL and LL are supported by the NIHR Oxford Biomedical Research CentrePeer reviewedPublisher PD
Migrant Nation-Builders: The Development of Austria-Hungary\u27s National Projects in the United States, 1880S-1920S
This dissertation charts the ways in which migrants from the Austro-Hungarian Empire crafted new forms of identification in the United States, complicating their relationships with their home and host states. Transatlantic migration and migrantsâ heightened nationalism were, I argue, causative factors in the dismantling of the Habsburg Empire into ethnically-based states after Word War I. Rather than focusing on a single ethnic group, Migrant Nation-Builders looks broadly at early multilingual immigrant institutions, Austro-Hungarian and American perceptions of panslavism, and the splintering of immigrant institutions in the United States along linguistic lines. The project traces the long arm of homeland authorities, especially the Hungarian government, in trying to manage migrant loyalty in America, and follows return migrants from the United States back to East Central Europe to track their influence on domestic politics. Finally, it examines the dual effects on migration of new borders in Eastern Europe and restrictive immigration legislation in the United States
A Quest for a Custom-Made Mesenchymal Stem Cell in the Treatment of Inflammatory Diseases
Mesenchymal stem cells (MSC) are multipotent cells that can differentiate into adipocytes, osteoblasts and chondrocytes. These cells are widely studied in tissue regeneration and for their therapeutic effects in inflammatory disease. MSC interact with cells of the innate and adaptive immunity to promote or suppress the inflammatory response. MSC from the bone marrow (D1 MSC) decrease inflammatory responses by lowering macrophage (Má¶Č) secretion of soluble factors such as nitric oxide (NO), interleukin-12 (IL-12) and tumor necrosis factor-α (TNFα). Aorta-derived MSC (mAo MSC) support the macrophage inflammatory response by contributing to NO secretion and enhancing secretion of TNFα by Má¶Č. Previous studies have isolated and enriched MSC populations using one or two specific cell surface markers and subsequently tested their functional properties in the regulation of immune cells. In this study we took a different approach. Using two populations of MSC with opposing immune regulatory function, we examined differences in their MSC-associated gene expression using PCR array. We sought to identify sets of MSC-associated genes that correlate with either suppression or support of the Má¶Č inflammatory response. Our results revealed that the mAo MSC express genes that potentiate chondrogenic differentiation, while the D1 MSC express genes that potentiate adipogenic and osteogenic differentiation. Our unique approach identified MSC populations that have greater propensity to develop into osteogenic and adipogenic lineages are immunosuppressive, while those with greater propensity to develop into chondrocytes are immuno-supportive. We have identified lineage potential as a way to select MSC populations for use in cell-based therapies of inflammatory disease
Design for behaviour change as a driver for sustainable innovation : challenges and opportunities for implementation in the private and public sectors
Over the last decade, design for behaviour change has become increasingly recognised as a strategy for enabling social change. Despite this, we are far from understanding its implementation, especially through the private and public sectors. This study has surveyed private and public sector stakeholders with regard to their current knowledge of, and approach to, design for behaviour change. The aim was to identify the challenges for professional stakeholders in understanding, accessing and implementing design for behaviour change. Underpinned by a literature review of design for behaviour change theories and approaches, an online survey and two focus groups with private and public sector stakeholders were conducted with particular focus on small and medium size enterprises (SMEs). The results identified that there is a significant disconnect between available theoretical knowledge of design for behaviour change and its practical implementation. Reasons for this include a lack of awareness and common language, of evidence based examples, and of evaluation methods and inter-sector collaborations. In response, a set of recommendations has been developed to propose ways forward for the wider understanding and application of design for behaviour change
A pilot randomised controlled trial of cognitive behavioural therapy for antenatal depression.
BACKGROUND: Few trials have evaluated the effectiveness of psychological treatment in improving depression by the end of pregnancy. This is the first pilot randomised controlled trial (RCT) of individual cognitive behavioural therapy (CBT) looking at treating depression by the end of pregnancy. Our aim was to assess the feasibility of delivering a CBT intervention modified for antenatal depression during pregnancy. METHODS: Women in North Bristol, UK between 8-18Â weeks pregnant were recruited through routine contact with midwives and randomised to receive up to 12 sessions of individual CBT in addition to usual care or to continue with usual care only. Women were eligible for randomisation if they screened positive on a 3-question depression screen used routinely by midwives and met ICD-10 criteria for depression assessed using the clinical interview schedule - revised version (CIS-R). Two CBT therapists delivered the intervention. Follow-up was at 15 and 33Â weeks post-randomisation when assessments of mental health were made using measures which included the CIS-R. RESULTS: Of the 50 women assessed for the trial, 36 met ICD-10 depression criteria and were randomised: 18 to the intervention and 18 to usual care. Thirteen of the 18 (72%) women who were allocated to receive the intervention completed 9 or more sessions of CBT before the end of pregnancy. Follow-up rates at 15 and 33Â weeks post-randomisation were higher in the group who received the intervention (89% vs. 72% at 15Â weeks and 89% vs. 61% at 33Â weeks post-randomisation). At 15Â weeks post-randomisation (the end of pregnancy), there were more women in the intervention group (11/16; 68.7%) who recovered (i.e. no longer met ICD-10 criteria for depression), than those receiving only usual care (5/13; 38.5%). CONCLUSIONS: This pilot trial shows the feasibility of conducting a large RCT to assess the effectiveness of CBT for treating antenatal depression before the end of pregnancy. The intervention could be delivered during the antenatal period and there was some evidence to suggest that it could be effective. TRIAL REGISTRATION: ISRCTN44902048
Reflections and Experiences of a Co-Researcher involved in a Renal Research Study
Background Patient and Public Involvement (PPI) is seen as a prerequisite for health research. However, current Patient and public involvement literature has noted a paucity of recording of patient and public involvement within research studies. There have been calls for more recordings and reflections, specifically on impact. Renal medicine has also had similar criticisms and any reflections on patient and public involvement has usually been from the viewpoint of the researcher. Roles of patient and public involvement can vary greatly from sitting on an Advisory Group to analysing data. Different PPI roles have been described within studies; one being a co-researcher. However, the role of the co-researcher is largely undefined and appears to vary from study to study. Methods The aims of this paper are to share one first time co-researcher's reflections on the impact of PPI within a mixed methods (non-clinical trial) renal research study. A retrospective, reflective approach was taken using data available to the co-researcher as part of the day-to-day research activity. Electronic correspondence and documents such as meeting notes, minutes, interview thematic analysis and comments on documents were re-examined. The co-researcher led on writing this paper. Results This paper offers a broad definition of the role of the co-researcher. The co-researcher reflects on undertaking and leading on the thematic analysis of interview transcripts, something she had not previously done before. The co-researcher identified a number of key themes; the differences in time and responsibility between being a coresearcher and an Advisory Group member; how the role evolved and involvement activities could match the co-researchers strengths (and the need for flexibility); the need for training and support and lastly, the time commitment. It was also noted that it is preferable that a co-researcher needs to be involved from the very beginning of the grant application. Conclusions The reflections, voices and views of those undertaking PPI has been largely underrepresented in the literature. The role of co-researcher was seen to be rewarding but demanding, requiring a large time commitment. It is hoped that the learning from sharing this experience will encourage others to undertake this role, and encourage researchers to reflect on the needs of those involved.Peer reviewedFinal Published versio
Joining forces:investigating the influence of design for behavior change on sustainable innovation
Design is a significant driver of behaviour change, enabling, encouraging or discouraging particular practices from taking place. Despite designâs clear influence on behaviours, no overarching framework exists for the effective implementation of Design for Behaviour Change (DfBC) in professional and public contexts. This paper takes a first step to synthesizing current models and approaches of DfBC, covering the thematics of ecological sustainability, safety, health and well-being, and social design. The review is supported by a range of case studies that illustrate the role of DfBC as a driver for sustainable innovation for small and medium size businesses (SME). The objective is to develop a better understanding of how to stimulate ecological and social innovations in SMEs that enable lasting behaviourchange. The findings of the review highlight opportunities and challenges for the effectiveimplementation of sustainable innovation through DfBC, in particular the lack of a holistic evidence base of the current understanding and application of DfBC
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