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Older adults at a high-risk of falling tend to look away from a current stepping target in order to look at obstacles ahead. This early gaze transfer impairs the accuracy of stepping. It has previously been shown that this maladaptive gaze behaviour is associated with increased anxiety. This thesis aimed to elucidate the causal relationships between anxiety, sub-optimal gaze behaviour and increased falls risk in older adults. In separate experiments we manipulated experimental conditions to: 1) increase older participants anxiety via Social Evaluative Threat 2) reduce anxiety via relaxation exercises and 3) alter the extent to which participants previewed obstacles and walking goals via a gaze training intervention. Increasing older adults’ anxiety resulted in reduced stepping performance, and a measured reduction in anxiety was accompanied by increased stepping performance. There were few effects on eye movement timing characteristics suggesting that these changes in stepping behaviour were not mediated by altered gaze strategies. Route previewing intervention resulted in significant changes to older adults’ gaze behaviour, and improved self-confidence and stepping performance. These findings highlight the possibility of using interventions aimed at reducing anxiety and/or guiding gaze behaviour to address falls-risk in older adults.

This thesis is concerned with macroeconomic and fiscal implications of fossil fuel combustion. Despite an emerging focus among economic policy makers on the problem of curbing greenhouse gas emissions, much remains to be learned about this complex issue. Fossil fuel related pollution, for example, is likely to impose a range of societal costs – including, potentially, on productivity, human health and household consumption patterns – which are typically not reflected in economic simulations aimed at informing the climate debate. Analysis of a broader set of potential energy-environmental spillovers here highlights new insights on the importance of theoretical assumptions, including in relation to savings behaviour, welfare aggregation and potential consumption externalities for the macroeconomy and fiscal policy. Distributional issues associated with potential energy tax reforms designed to control externalities and raise revenues are also studied in an effort to inform decision makers in the UK on the consequential risks - and mitigating strategies - to the well-being of societal groups, including lower income households.

Formic acid and nitric acid have been found to contribute to aerosol formation and are key components of acidity in the troposphere. Tropospheric measurements of these species are often limited, resulting in major uncertainties when assessing their effects on the climate. Current global chemistry-transport models significantly under-predict formic acid concentrations, particularly in the mid-to-high latitudes of the Northern Hemisphere. Furthermore, large discrepancies exist in the role played by dinitrogen pentoxide on nitric acid production between two recently documented models assessing the global nitric acid budget. In order to accurately constrain the budget of these acids in the mid-to-high latitudes of the Northern Hemisphere, it is crucial that these uncertainties are addressed. In this work, airborne measurements of formic acid, nitric acid and dinitrogen pentoxide are presented from across different regions of the Northern Hemisphere to investigate direct and indirect sources contributing to the formic acid and nitric acid regional budgets. Measurements were collected using a Chemical Ionisation Mass Spectrometer (CIMS) fitted to the Facility for Atmospheric Airborne Measurements (FAAM) BAe-146 aircraft. Formic acid measurements within the European Arctic during March and July 2012 would indicate ocean sources dominate over terrestrial sources irrespective of seasonality. CH2I2 photolysis and oxidation was hypothesised as a marine source of formic acid. Modelled estimates would indicate the CH2I2 reaction route may represent a significant summer marine source of formic acid within the Fenno-Scandinavian Arctic. Additionally, low altitude aircraft measurements taken within the Fenno-Scandinavian Arctic over regions occupied by wetlands in August 2013 were used to calculate a formic acid surface flux. Results would suggest formic acid emission from wetlands may represent up to 37 times greater than its globally inferred estimate. A flux measurement conducted over a comparable region in September 2013 observed a negative flux, indicating a change of this region from a net source to a net sink of formic acid. The inconsistency of this regional wetland source confirms the need for in-depth studies on formic acid emission from wetlands, in order to better understand its contribution to the regional and global formic acid budget. In a separate study, significant daytime elevations of N2O5 and HNO3 concentrations were observed within identified biomass burning plumes off the eastern coast of Canada. In-plume correlations between N2O5 and HNO3 concentrations observed within these environments suggest N2O5 was acting as additional daytime source of gaseous HNO3 when subjected to photolytically-limited conditions. This result has important implications to ozone production and provides evidence for an additional daytime source of nitric acid, which must be included in chemistry models calculating the global nitric acid budget.

As superorganisms, eusocial insect colonies possess both individual and social strategies for epidemic control. Both the physiological immune system within individuals and an array of social behaviours, such as self–quarantine, collectively comprise the colony’s immunocompetence. Diet is a modulator of immunocompetence in insects and furthermore insects can self-medicate by ingesting nutrients that promote immunocompetence. However, how diet impacts multiple strategies of epidemic control both physiologically and through social behavioural processes, within a superorganism is not known. Therefore, the central aim of this thesis is to elucidate the role of diet for immunocompetence in the eusocial European honey bee (Apis mellifera). In the first data chapter (Chapter 2), I set the framework for measuring honey bee immunocompetence by describing a time course for the expression of two key components of the physiological immune system after challenge; the phenoloxidase pathway and antimicrobial peptides. I establish that only antimicrobial activity is elicited by an experimental pseudo-bacterial challenge and I identify appropriate time points to assess the impact of diet on immunocompetence. I demonstrate that short-term pollen starvation has no impact on physiological immunocompetence. In chapter 3 I show that a pseudo-bacterial challenge causes honey bees to adopt a diet that reduces their intake of pollen, whilst maintaining their intake of carbohydrates and I demonstrate that immunologically challenged honey bees forage more intensively. Based on these two findings, I therefore propose that a dietary mechanism underlies increased foraging intensity, which is adaptive as a form of nutritional targeting for self-removal to reduce colony infection. In chapter 4, I demonstrate that a sustained lack of essential amino acids both promotes antimicrobial peptide activity and reduces longevity. Furthermore, I show that, like the trend observed with pollen consumption, a pseudo-bacterial challenge causes honey bees to reduce their intake of essential amino acids, Taken together, these results provide new support for the proposition that through dietary modulation, honey bees nutritionally self-medicate at the level of the superorganism in order to reduce in-hive rates of pathogen transmission by increased physiological immunocompetence, self-removal, and mortality in infected individuals.

Through this practice-based research I interrogate the terms community art, activism, social and digital media, as well as community and place. It is an investigation into both theoretical and practical aspects of community art practice and its connection to national and local policies on community, arts and digital media. It considers the increasing role digital technology and social media have in communities and community organisations, in particular under the guise of austerity, and how community organisations (do not) use social media and digital technology to encourage participation. It considers my position and role as an artist, curator and resident within the community that I live in and how, through becoming active and engaged with the place, I can develop a strategy for sustainable and long-term social engagement. This practice based Ph.D. takes as a starting point the stalled housing regeneration, due to the halting of the Housing Market Renewal Pathfinder, in the community where I live. The research builds upon my experience of working as an artist, curator and arts educator since the turn of the millennium where, under consecutive governments the purpose of contemporary art and its educational use has either been to effect social change (New Labour) or its economic value (current coalition government). Through the creation of a series of participatory and digital engagement events and workshops the research interrogates and considers the connections and conflict between the ‘physical’ (public space) and the digital and supposedly ‘open’ (the online). The research will be of use to those who feel an increasing and urgent need to engage with their own community as practitioners as well as community members.