The prediction and control of transients in thyristor values

This thesis describes an investigation of methods by which both repetitive and non-repetitive electrical transients in an HVDC converter station may be controlled for minimum overall cost. Several methods of inrush control are proposed and studied. The preferred method, whose development is reported in this thesis, would utilize two magnetic materials, one of which is assumed to be lossless and the other has controlled eddy-current losses. Mathematical studies are performed to assess the optimum characteristics of these materials, such that inrush current is suitably controlled for a minimum saturation flux requirement. Subsequent evaluation of the cost of hardware and capitalized losses of the proposed inrush control, indicate that a cost reduction of approximately 50% is achieved, in comparison with the inrush control hardware for the Sellindge converter station. Further mathematical studies are carried out to prove the adequacy of the proposed inrush control characteristics for controlling voltage and current transients during both repetitive and non-repetitive operating conditions. The results of these proving studies indicate that no change in the proposed characteristics is required to ensure that integrity of the thyristors is maintained.

Migration and mobility of new Polish migrants in England:narratives of lived experience

This thesis sets out to understand the act of migrating in a period of growing movement of people. It captures the subjective experience of individual migrants, as narrated in the migration stories of 32 “new” Polish migrants in the West Midlands region of England. Since the enlargement of the European Union in 2004, over half a million Poles have arrived and registered to work in the UK, constituting one of the largest migration movements in contemporary Britain and Europe. This influx of predominantly young migrants opened up public and academic debates regarding the social relations between the Polish migrants and the host society, their duration of stay, and the impact on the economy and social services. While a substantial amount of research has now been undertaken on this migration, this thesis highlights some of the significant features of migration to Britain and Europe today, namely its dynamic, fluid, complex and varied character. Through four themes of lived experience of migration, migration and mobility, gender, and return migration, this thesis uncovers and explores the phenomenon of post-2004 EU migration from the perspective of migrants themselves. Migrant stories in this thesis are linked with experiences and meanings of migration, but also migrants’ emotions, perceptions, views and opinions. By exploring individual journeys of migration and deliberating over the determinants and consequences of migration, this thesis asks how the processes of migration and mobility come into play in the everyday lives of migrant people, and how this impacts on questions of identity, home, belonging, gender, as well as return.

Diaspora identification and long-distance nationalism among Tamil migrants of diverse state origins in the UK

Accounts of Tamil long-distance nationalism have focused on Sri Lankan Tamil migrants. But the UK is also home to Tamils of non-Sri Lankan state origins. While these migrants may be nominally incorporated into a 'Tamil diaspora', they are seldom present in scholarly accounts. Framed by Werbner's (2002) conception of diasporas as 'aesthetic' and 'moral' communities, this article explores whether engagement with a Tamil diaspora and long-distance nationalism is expressed by Tamil migrants of diverse state origins. While migrants identify with an aesthetic community, 'membership' of the moral community is contested between those who hold direct experience of suffering as central to belonging, and those who imagine the boundaries of belonging more fluidly - based upon primordial understandings of essential ethnicity and a narrative of Tamil 'victimhood' that incorporates experiences of being Tamil in Sri Lanka, India and in other sites, despite obvious differences in these experiences. © 2013 Taylor & Francis.

Cosmopolitans and 'cliques':everyday socialisation amongst Tamil student and young professional migrants to the UK

Among student and young professional migrants to the UK the opportunity for a global or cosmopolitan experience emerges as a motivating factor for migration. This article takes the example of student and young professional migrants to the UK from the South Indian state of Tamil Nadu, and explores how this cosmopolitan ambition plays out in the formation of UK social networks. Two 'types' of research participant are identified; 'self-conscious cosmopolitans' whose social networks are cross-ethnic, and others whose networks are largely co-ethnic and who are often derided by their self-consciously cosmopolitan counterparts as 'clannish' or 'cliquey'. The article asks how ethnicity emerges as salient (or not) in these migrants' talk and practice around UK social network formations. It then considers whether a co-ethnic social network necessarily limits the cosmopolitan experience, or whether this interpretation reflects a narrow understanding of cosmopolitanism which excludes the multiple inter-cultural encounters these migrants experience in their everyday lives. © The Author(s) 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Being Tamil, being Hindu:Tamil migrants’ negotiations of the absence of Tamil Hindu spaces in the West Midlands and South West of England

This paper considers the religious practices of Tamil Hindus who have settled in the West Midlands and South West of England in order to explore how devotees of a specific ethno-regional Hindu tradition with a well-established UK infrastructure in the site of its adherents’ population density adapt their religious practices in settlement areas which lack this infrastructure. Unlike the majority of the UK Tamil population who live in the London area, the participants in this study did not have ready access to an ethno-religious infrastructure of Tamil-orientated temples and public rituals. The paper examines two means by which this absence was addressed as well as the intersections and negotiations of religion and ethnicity these entailed: firstly, Tamil Hindus’ attendance of temples in their local area which are orientated towards a broadly imagined Hindu constituency or which cater to a non-Tamil ethno-linguistic or sectarian community; and, secondly, through the ‘DIY’ performance of ethnicised Hindu ritual in non-institutional settings.

Experiencing transnationalism at home:open borders and the everyday narratives of non-migrants

The normative migration rights literature has engaged with the situated experience of migration to a very limited extent, with particularly little attention paid to non-migrants living in receiving localities. This article argues that exploring the non-elite narratives of non-migrants provides valuable insights for normative theorising about migration rights. The discussion is illustrated with a description of research undertaken within rural migration-receiving communities in England, which shows how the narratives of non-migrants shape the experience of migration at a micro-level. This article discusses the implications of this research for normative theory in order to demonstrate the value of this methodological approach.

Migrants and the Hungarian Society. Dignity, Justice and Civic Integration

The aim of the research was to explore the integration, political and civic participation of "third country nationals residing in Hungary" (hereafter, immigrants or migrants). How immigrants and Hungarian society interpret political and civic activity was examined, along with how this is correlated to their material, cultural and social resources (using such concepts as identity and action potential, as well as the sense of fairness and dignity). The samples do represent Hungarian society and those people staying in Hungary with immigration or residence permits/ permanent residence (collectively labeled as immigrants). It should be stressed that the immigrants we studied are not refugee camp dwellers or foreigners employed illegally in Hungary. Though themselves faced with a lot of problems, the immigrants we interviewed are in a far more favorable position than refugees or aliens employed in the grey economy. This is an important fact to be remembered when reading about the research.

Direct In Vivo Manipulation and Imaging of Calcium Transients in Neutrophils Identify a Critical Role for Leading-Edge Calcium Flux.

Calcium signaling has long been associated with key events of immunity, including chemotaxis, phagocytosis, and activation. However, imaging and manipulation of calcium flux in motile immune cells in live animals remain challenging. Using light-sheet microscopy for in vivo calcium imaging in zebrafish, we observe characteristic patterns of calcium flux triggered by distinct events, including phagocytosis of pathogenic bacteria and migration of neutrophils toward inflammatory stimuli. In contrast to findings from ex vivo studies, we observe enriched calcium influx at the leading edge of migrating neutrophils. To directly manipulate calcium dynamics in vivo, we have developed transgenic lines with cell-specific expression of the mammalian TRPV1 channel, enabling ligand-gated, reversible, and spatiotemporal control of calcium influx. We find that controlled calcium influx can function to help define the neutrophil's leading edge. Cell-specific TRPV1 expression may have broad utility for precise control of calcium dynamics in other immune cell types and organisms.

Picking on vulnerable migrants: precarity and the mushroom industry in Northern Ireland

This article examines precarious employment in the context of the mushroom industry in Northern Ireland. Migrant workers engaged in mushroom picking were interviewed in the context of wider research investigating forced labour in Northern Ireland. The research found that, while the boundaries between exploitation and forced labour are complex and difficult to discern, there was some evidence of borderline forced labour, according to ILO definitions. However, workers found themselves on a ‘continuum of exploitation’, where initial engagement with the prospect of decent work was superseded by increasing endurance of exploitative practices, brought about by unequal power relationships with employers originating in immigration status. This is examined in the wider theoretical context of precarity, of which precarious employment comprises a part.

The effects of transients on photospheric and chromospheric power distributions

We have observed a quiet Sun region with the Swedish 1-meter Solar Telescope (SST) equipped with CRISP Imaging SpectroPolarimeter. High-resolution, high-cadence, H-alpha line scanning images were taken to observe different layers of the solar atmosphere from the photosphere to upper chromosphere. We study the distribution of power in different period-bands at different heights. Power maps of the upper photosphere and the lower chromosphere show suppressed power surrounding the magnetic-network elements, known as "magnetic shadows". These also show enhanced power close to the photosphere, traditionally referred to as"power halos". The interaction between acoustic waves and inclined magnetic fields is generally believed to be responsible for these two effects. In this study we explore if small-scale transients can influence the distribution of power at different heights. We show that the presence of transients, like mottles, Rapid Blueshifted Excursions (RBEs) and Rapid Redshifted Excursions (RREs), can strongly influence the power-maps. The short and finite lifetime of these events strongly affects all powermaps, potentially influencing the observed power distribution. We show that Doppler-shifted transients like RBEs and RREs that occur ubiquitously, can have a dominant effect on the formation ofthe power halos in the quiet Sun. For magnetic shadows, transients like mottles do not seem to have a significant effect in the power suppression around 3 minutes and wave interaction may play a key role here. Our high cadence observations reveal that flows, waves and shocks manifest in presence of magnetic fields to form a non-linear magnetohydrodynamic system.

The mental health and wellbeing of first generation migrants: a systematic-narrative review of reviews

Background
First generation migrants are reportedly at higher risk of mental ill-health compared to the settled population. This paper systematically reviews and synthesizes all reviews on the mental health of first generation migrants in order to appraise the risk factors for, and explain differences in, the mental health of this population.
Methods
Scientific databases were searched for systematic reviews (inception-November 2015) which provided quantitative data on the mental ill-health of first generation migrants and associated risk factors. Two reviewers screened titles, abstracts and full text papers for their suitability against pre-specified criteria, methodological quality was assessed.
Results
One thousand eight hundred twenty articles were identified, eight met inclusion criteria, which were all moderate or low quality. Depression was mostly higher in first generation migrants in general, and in refugees/asylum seekers when analysed separately. However, for both groups there was wide variation in prevalence rates, from 5 to 44 % compared with prevalence rates of 8–12 % in the general population. Post-Traumatic Stress Disorder prevalence was higher for both first generation migrants in general and for refugees/asylum seekers compared with the settled majority. Post-Traumatic Stress Disorder prevalence in first generation migrants in general and refugees/ asylum seekers ranged from 9 to 36 % compared with reported prevalence rates of 1–2 % in the general population. Few studies presented anxiety prevalence rates in first generation migrants and there was wide variation in those that did. Prevalence ranged from 4 to 40 % compared with reported prevalence of 5 % in the general population. Two reviews assessed the psychotic disorder risk, reporting this was two to three times more likely in adult first generation migrants. However, one review on the risk of schizophrenia in refugees reported similar prevalence rates (2 %) to estimates of prevalence among the settled majority (3 %). Risk factors for mental ill-health included low Gross National Product in the host country, downward social mobility, country of origin, and host country.
Conclusion
First generation migrants may be at increased risk of mental illness and public health policy must account for this and influencing factors. High quality research in the area is urgently needed as is the use of culturally specific validated measurement tools for assessing migrant mental health.

Health, ageing migrants and care strategies

This article is the result of a study that seeks to understand the relationship between socio-economic conditions, health and active ageing. Behaviours related to active ageing in relation to health were identified as were the strategies used in active ageing and their determinants. A qualitative methodology was adopted in the form of semi-structured interviews. Data processing consisted of thematic content analysis in interviews. Two socio-economic groups of elderly Cape Verdean men and women composed the study sample. Both groups totalled 22 cases. Findings indicated that the socio-economic status interferes directly in the affairs of active ageing rather than health issues. In the higher socio-economic group, it was found that status determines active ageing rather than health issues.