Radiochemical studies of ion-exchange

The first part of the work described in this thesis deals with the preparation of uniformly thin sources suitable for the counting of weak β-emitting radioisotopes. The method developed involved the preparation of a thin sulphonated polystyrene layer supported on a thin VYNS film on which cations were deposited by ion-exchange. The p-counting efficiency of the sources in a 4 II β-proportional counter was determined by coincidence counting. Autoradiography was used to determine the uniformity of the sources. Evaporated gold on the VYNS film support was found to promote the surface diffusion of mercury and investigations led to a procedure applicable to the measurement of the counting efficiency of p-emitting mercury isotopes; a method for the calibration of a proportional counter used in the determination of the Tl(^203)(n,pHg(^203) cross-section was thereby evolved. In Part II preliminary experiments were directed towards finding a suitable "liquid ion exchanger" for an investigation of ion-exchange behaviour, particularly at high electrolyte concentrations; mono-(2-ethylhexyl) phosphoric acid (H(_2)MEHP) in toluene was eventually selected

Comparison of trends in butterfly populations between monitoring schemes

Butterflies are an important indicator of the impacts of environmental change. Butterfly monitoring schemes (BMS) have provided national and Europe-wide trends in their abundance and been widely used for research. Most schemes sample sites that are self-selected by contributors and therefore tend to cover locations that are rich in butterflies. To provide a more representative assessment of butterfly populations, the wider countryside butterfly survey (WCBS) was developed with a stratified-random sample of survey sites across the UK. We compare butterfly trends from the WCBS locations against those measured from traditional butterfly transects which are typically located in areas of good quality semi-natural habitats. Across the 26 species analysed, there was a significant positive relationship between trends measured from the two schemes between 2009 and 2013, the period when both schemes were operating fully. There was a tendency (17 out of 26 species analysed) for these changes to be greater within WCBS compared to traditional BMS transects, although this effect was not consistent across comparisons between pairs of consecutive years. When assessing these individual year-to-year changes, there was however a significant correlation between the two schemes in all cases. Over relatively short time periods, weather patterns are likely to dominate butterfly population fluctuations and lead to comparable trends across monitoring schemes. Over longer time periods, differences in land management may affect habitat condition differently for protected areas versus the wider countryside and it is therefore important to maintain comprehensive butterfly monitoring programmes to detect and interpret such effects

Getting in, getting on, getting out? Women as career scramblers in the UK film and television industries

This article looks at the predominance of freelancing in the film and television industries as a lens to examine the persistence of gender inequalities within these fields. Previous research has indicated that women fare better in larger organizations with more stable patterns of employment, and in this article we explore why that might be the case, by focusing on the experiences of female freelancers at a moment when project-based, precarious work and informal recruitment practices are increasing in the UK film and television sector. We highlight in particular the ways in which gender inequality is mediated by age and parental status, and the impact of intersectional identities on women's ability to sustain a career in film and television

The Growth of Eimeria tenella: Characterization and Application of Quantitative Methods to Assess Sporozoite Invasion and Endogenous Development in Cell Culture

In vitro development of the complete life cycle of Eimeria species has been achieved in primary cultures of avian epithelial cells with low efficiency. The use of immortalized cell lines simplifies procedures but only allows partial development through one round of parasite invasion and intracellular replication. We have assessed the suitability of Madin-Darby Bovine Kidney (MDBK) cells to support qualitative and quantitative studies on sporozoite invasion and intracellular development of Eimeria tenella. Analysis of parasite ultrastructure by transmission electron microscopy and serial block face—scanning electron microscopy proved the suitability of the system to generate good quality schizonts and first-generation merozoites. Parasite protein expression profiles elucidated by mass spectrometry corroborated previous findings occurring during the development of the parasite such as the presence of alternative types of surface antigen at different stages and increased abundance of proteins from secretory organelles during invasion and endogenous development. Quantitative PCR (qPCR) allowed the tracking of development by detecting DNA division, whereas reverse transcription qPCR of sporozoite- and merozoite-specific genes could detect early changes before cell division and after merozoite formation, respectively. These results correlated with the analysis of development using ImageJ semi-automated image analysis of fluorescent parasites, demonstrating the suitability and reproducibility of the MDBK culture system. This systems also allowed the evaluation of the effects on invasion and development when sporozoites were pre-incubated with anticoccidial drugs, showing similar effects to those reported before. We have described through this study a series of methods and assays for the further application of this in vitro culture model to more complex studies of Eimeria including basic research on parasite cell biology and host-parasite interactions and for screening anticoccidial drugs

Freelance networks, trade unions and below-the-line solidarity in regional film and television clusters: An interview with the Bristol editors network

This article consists of an introduction and extended interview transcript conducted with several members of the Bristol Editors’ Network (BEN), an organization established in May 2015 to support the large community of editors that work in and around Bristol and the South West of England. The interview transcript is significant for several reasons. First and foremost, it provides a rich account of what it is like to freelance within the third-largest film and television production cluster in the UK, after London and Manchester. In doing so, the transcript also offers an insight into the sometimes-fraught state of contemporary industrial relations between the region’s employers and its largely freelance workforce. Moreover, the transcript provides an account of how, by establishing BEN, Bristol editors are working to defend themselves against exploitative practices in the cluster, fostering a mutually-supportive freelance community and contributing to a more effective, equitable production culture in the city

Prospects for local co-governance

British local authorities and their partners are increasingly developing new ways of working together with local communities. The nature of this co-working, however, is complex, multi-faceted and little understood. This article argues for greater clarity of thinking on the topic, by analysing this co-working as a form of political co-governance, and drawing attention in particular to issues of scale and democracy. Using evidence from a study of 43 local authority areas, 16 authorities are identified where co-governance is practised, following three main types of approach: service-influencing, service-delivering and parish council developing. It is concluded that strengthening political co-governance is essential for a healthy democracy

Population characteristics of Shovelnose Sturgeon during low- and high-water conditions in the lower Platte River, Nebraska

Cycles of low- and high-water periods (i.e., years) in river systems are natural occurrences, but understanding how cyclical climatological patterns affect fishes, especially long-lived species, is unclear. We assessed Shovelnose Sturgeon population dynamics between a period of low- (2001-2004) and high- (2009-2012) water years in the lower Platte River, Nebraska. Low-flow periods in the lower Platte River can cause disconnection(s) between upstream and downstream reaches resulting in isolated pools and elevated water temperatures leading to stressful situations for aquatic life and possible mortality. Our data show no measurable differences between key population indices between flow condition periods which is consistent with current paradigms for long-lived fish species. Shovelnose Sturgeon relative weights were generally \u3e 80 during both low- and high-water periods and the size structure did not differ between the two periods. Shovelnose Sturgeon abundances, however, were greater during high-water conditions compared to low-water conditions (Kruskal-Wallis: χ2 = 6.15, d.f. = 1, P = 0.01). Shovelnose Sturgeon may have migrated to more suitable habitats during low-water periods to seek refuge allowing these individuals to return during more suitable conditions. Shovelnose Sturgeon and other riverine fish have evolved in a variable environment and have been able to endure relatively minor anthropogenic changes within the lower Platte River. Rivers like the lower Platte River that have retained much of their original physical features and flow regimes are likely key components for the resistance and resilience of riverine species. However, as alterations to landscapes continue and uncertainty exists surrounding future climate predictions, it is unknown how these riverine species will be able to adapt to future changes. The reduction in anthropogenic changes that disrupt flow regimes and increasing connectivity among river systems could provide more fish refuge during stressful conditions helping to protect these riverine species