In the first part of this thesis, we address the problem of separating stars from galaxies in future large photometric surveys. We derive the science requirements on star/galaxy separation, for measurement of the cosmological parameters with the Gravitational Weak Lensing and Large Scale Structure probes, in chapter 2. We formulate the requirements in terms of the completeness and purity provided by a given star/galaxy classifier. In order to achieve these requirements, we propose a new method for star/galaxy separation in chapter 3, combining Principal Component Analysis with an Artificial Neural Network. When tested on simulations of the Dark Energy Survey (DES), this multi-parameter approach improves upon purely morphometric classifiers (such as the classifier implemented in SExtractor), especially at faint magnitudes. Chapter 4 is dedicated to the testing of this tool on real data, namely the recent internal release of DES Science Verification data. In the second part and last chapter of this thesis, chapter 5, we develop a method to detect the modulation by Baryonic Acoustic Oscillations of the density ratio of baryon to dark matter across large regions of the Universe. Such a detection would provide a direct measurement of a difference in the large-scale clustering of mass and light and a confirmation of the standard cosmological paradigm from a different angle than any other measurement. We measure the number density correlation function and the luminosity weighted correlation function of the DR10 releases of the Baryon Oscillation Spectroscopic Survey (BOSS), and fit a model of scale dependent bias to our measurement. Although our measurement is compatible with previous theoretical predictions, more accurate data is needed to prove or disprove this effect.

Transition metal oxides containing a 5d element are increasingly attracting attention as an arena in which to search for novel electronic states. These are proposed to derive from the interplay between the strong spin-orbit interaction (SOI) in the 5ds, the electronic correlations and crystal field effects. Iridium based compounds have featured predominantly in this quest, with considerable focus on the layered perovskites in which a novel “spin-orbit induced” Mott-like insulating state emerges. In this case, the SOI leads to the jeff = 1/2 ground state for the Ir4+ (5d5) ions observed in Sr2IrO4. In this thesis I demonstrate that resonant X-ray scattering techniques at the Ir L edges are a valuable tool to investigate the electronic and magnetic properties of iridium oxides. In particular the evolution of the jeff = 1/2 state as a function of structural distortions in the single layer iridates Sr2IrO4 and Ba2IrO4, and as a function of the dimensionality in the bilayer Sr3Ir2O7 is investigated. My findings show that the magnetic and electronic structures in the single layered perovskites are remarkably robust to structural distortions. Conversely, adding an extra IrO6 layer (Sr2IrO4 →Sr3Ir2O7) the ground and excited states change dramatically. Both these phenomena can be linked directly to the unique three-dimensional character of the jeff = 1/2 state. Furthermore, the X-ray resonant scattering cross-section of Ir4+ at the L2,3 edges, calculated in a single-ion model, shows a non-trivial dependence on the direction of the magnetic moment, μ. These results provide important insights into the interpretation of X-ray data from the iridates, including that a jeff = 1/2 ground state cannot be assigned on the basis of L2/L3 intensity ratio alone.

This thesis studies several topics in the area of weak gravitational lensing and addresses some key statistical problems within this subject. A large part of the thesis concerns the measurement of galaxy shapes for weak gravitational lensing and the systematics they introduce. I focused on studying two key effects, typical for model-fitting shape measurement methods. First is noise bias, which arises due to pixel noise on astronomical images. I measure noise bias as a function of key galaxy and image parameters and found that the results are in good agreement with theoretical predictions. I found that if the statistical power of a survey is to be fully utilised, noise bias effects have to be calibrated. The second effect is called model bias, which stems from using simple models to fit galaxy images, which can have more complicated morphologies. I also investigate the interaction of these two systematics. I found model bias to be small for ground-based surveys, rarely exceeding 1%. Its interaction with noise bias was found to be negligible. These results suggest that for ongoing weak lensing surveys, noise bias is the dominant effect. Chapter 5 describes my search for a weak lensing signal from dark matter filaments in CFHTLenS fields. It presents a novel, model-fitting approach to modelling the mass dis- tribution and combining measurements from multiple filaments. We find that CFHTLenS data does provide very good evidence for dark matter filaments, with detection significance of 3.9σ for the filament density parameter relative to mean halo density of connected halos at their R200. For 19 pairs of the most massive halos, the integrated density contrast of filaments was found on a level of 1 · 1013M⊙/h. The appendices present my contribution to three other papers. They describe practical applications of the calibration of noise bias in the GREAT08 challenge and the Dark Energy Survey. I also present the results of the validation of reconvolution and image rendering using FFTs in the GalSim toolkit.

The aim of the studies presented in this thesis was to develop a screen-printed electrochemical biosensor for the measurement of glutamate and to apply this device to the determination of the analyte in food, serum and toxicity studies. Chapter 1 serves as an introduction to both the physiological significance of glutamate and the fundamental principles underpinning the electrochemical techniques used throughout this thesis. Chapter 2 is a review chapter, separated into two main sections. The first section details glutamate biosensors fabricated with glutamate oxidase (GluOx), the second section details biosensors fabricated with glutamate dehydrogenase (GLDH). The immobilization techniques, ease of fabrication and sample preparation techniques employed are compared. Biosensor characteristics such as sensitivity, limit of detection and linear range are summarised within a table. The studies described in Chapter 3 focus on the development of a non-reagentless glutamate biosensor. A Meldola’s Blue screen-printed carbon electrode (MB-SPCE) was employed as the base transducer. The biosensor was constructed by drop coating the biopolymer chitosan (CHIT) and GLDH onto the surface of the MB-SPCE. For this study, NAD+ was present in free solution. Meldola’s Blue served as the electrocatalyst, whereby NADH produced by the GLDH/NAD+ reaction, was electrocatalytically oxidised at a low operating potential (+0.1V (vs. Ag/AgCl)). The applied potential, temperature, pH and concentration of the co-factors required for the biosensor operation were optimised in this study. The assay exhibited a linear range of 12.5 µM to 150 µM, limit of detection of 1.5 µM, response time of 2s and a sensitivity of 0.44 nA/ µM. The optimised biosensor was subsequently applied to the determination of endogenous and fortified concentrations of glutamate in both serum and food samples (OXO cubes). The serum was fortified with and the resulting mean recovery was 96% with a CV of 3.3% (n = 6). For the food sample, an unfiltered beef OXO cube was analysed for monosodium glutamate (MSG) content. The endogenous content of MSG was 125.43 mg/g, with a CV of 8.98% (n = 6). The solution was fortified with 100mM of glutamate and a resulting mean recovery of 91% with a CV of 6.39% (n = 6) was determined. In Chapter 4, the glutamate biosensor was further developed in order to produce a reagentless device whereby the cofactor NAD+ and GLDH were immobilized on to the surface of the electrode utilising CHIT. The reagentless device was developed in order to monitor glutamate release from human liver carcinoma cells (HepG2) as a result of cell toxicity from exposure to paracetamol. The biosensor was miniaturised in the form of a microband biosensor, whereby one dimension of the electrode is of micrometre size and the other millimetre size. Micro bands exhibit unique diffusion properties in comparison to conventional sized electrodes. Calibration studies were carried out with an applied potential of +0.1V (vs. Ag/AgCl) using both phosphate buffer and cell media. In phosphate buffer the following microband biosensor characteristics were determined: linear range; 25 - 125µM, sensitivity; 0.0636 nA/µM and a theoretical limit of detection of 1.20µM. In cell media; linear range; 25 – 150 µM, sensitivity; 0.128 nA/µM and a theoretical limit of detection of 4.2µM. As the HepG2 cells were grown in an incubator at a fixed temperature and pH, studies were carried out at pH 7, 37ºC, in a 5% CO2 atmosphere. The miniaturised biosensor was applied to the determination of glutamate and the quantification was done by standard addition in cell media after 24 hours exposure to various concentrations of paracetamol. The average endogenous concentrations for glutamate released from the HepG2 cells was 52.07µM (CoV: 13.74%, n = 3), 93.30µM (CoV: 18.41%, n = 3) and 177.14µM (CoV: 14.54% n = 3) for 1mM, 5mM, 10mM doses of paracetamol respectively. The microband biosensor was also applied to the real time monitoring of glutamate over 8 hours. The standard deviations for the final current generated after eight hours are as follows; 1mM (coefficient of variation (CoV): 3.3%), 5mM (CoV: 9.056%) and 10mM (CoV: 13.18%). The study showed that the magnitudes of the steady state currents increased in proportion to the concentration of added paracetamol. The study also demonstrated the possibility of applying microband biosensors, over extended time periods, for toxicity studies; there is no significant removal of analyte owning to the small biosensor dimensions. Chapter 5 describes the development of a reagentless conventional sized glutamate biosensor whereby the cofactor NAD+ and GLDH were immobilized using a combination of multi-walled carbon nanotubes (MWCNT), CHIT and additional water based MB in a layer-by-layer fashion. The MWCNT/CHIT/MB combination facilitates electron transfer to the surface of working electrode. The MWCNT/CHIT also entraps GLDH and the NAD+ on the surface of the electrode. The pH, temperature, optimum applied potential, concentrations of NAD+, CHIT and the addition of water-based MB were optimised. The electrocatalyst MB allowed a operating potential of +0.1V (vs. Ag/AgCl) to be utilised. The biosensor was examined with standard glutamate solutions and the following biosensor characteristics were determined; linear range; 7 - 105µM, LOD; 3 µM, sensitivity; 0.39 nA/µM, response time 20-30s. A food sample was analysed for MSG and found to contain 90.56 mg/g with a CV of 7.52% (n = 5). The reagentless biosensor was also applied to the determination of glutamate in serum. The endogenous concentration was found to be 1.44mM (n = 5), CV: 8.54%. The recovery of glutamate in fortified serum was 104% (n = 5), CV of 2.91%. The results indicate that the new biosensor holds promise for food and biomedical studies.

This is the first study in the British Isles detailing the spatial and temporal distribution and controls on testate amoebae within minerotrophic brown-moss dominated mires. The study covers a full annual cycle at two mires, Max Bog in North Somerset and Shapwick Heath on the Somerset Peat Moors, between 1st June 2009 and 31st May 2010. Groundwater and host substrate samples were collected fortnightly and quarterly. Precipitation inputs compared well with 30-year averages, which revealed that total rainfall was typical, despite there being an unusually wet summer and dry spring recorded at each site. Water table depth responded differentially to precipitation at both sites, with Shapwick Heath far more responsive. This is likely to be a result of a combination of site topography and the nature of the underlying substrate. Spatially, each site had specific testate amoebae communities which were strongly linked to substrate. This was particularly evident at Max Bog. Spatial variability across both mires was driven by the relative abundance of a few key species. A larger number of more variable species then contributed at the individual biotope level. No vertical micro-distribution in the bryophytes was observed which was probably owing to the lack of both mixotrophic species and the moisture gradient. Temporal analysis showed that testate amoebae exhibited seasonal responses which were variable between the two sites and were represented by compositional change in the warmer periods of spring and summer. The strength and pattern of seasonality varied between communities inhabiting different biotopes. Seasonal shifts in bryophyte communities were generally represented by shifts in species dominance, while in other biotopes, seasonal variability was driven by species presence and absence. No vertical difference in seasonality was recorded in the bryophytes. Substrate variables were the principal controls on the broader species spatio-temporal distribution, particularly pH and Ca2+. There was very limited influence of both the water table and groundwater variables at Max Bog. Groundwater was far more influential at Shapwick Heath, although secondary to substrate variables. There was no consistent pattern of control between communities. Four test types were recorded overall. The numerically dominant test type at both sites was idiosomic. Although they exhibited some spatial variability, temporally they were stable. Major differences were due to relative fluctuations of xenosomes and protein-calcium tests. Vertically, there was no difference in test type composition. The dominance of the idiosome tests can have a significant impact on the quality of palaeo-environmental reconstruction in minerotrophic mires through the loss of ecological information and the potential underestimation of depth to water table (DWT). Furthermore, the use of testate amoebae in hydrological reconstructions in these systems may be severely limited, owing to the strong link with host substrate. The data suggest, however, that fen-dwelling testate amoebae may be useful in bio-monitoring, mire restoration and conservation research.

Polymyalgia rheumatica (PMR) is a chronic inflammatory condition which affects the elderly, causing aching and stiffness of the neck, shoulders and pelvis, as well as more systemic manifestations such as fever, malaise and fatigue. PMR shares symptoms with rheumatoid arthritis (RA) and both are associated with significantly elevated circulating concentrations of interleukin-6 (IL-6), which is thought to play a key role in the pathogenesis of these diseases. In RA, IL-6 is derived from synovial cells in the joints. In PMR, however, the source of IL-6 is unknown. PMR patients do not exhibit the same joint involvement as in RA but they do have elevated circulating IL-6 concentrations, thus, it was hypothesised that the source of IL-6 in PMR may be one of the circulating peripheral blood mononuclear cell (PBMC) types, which are all capable of producing IL-6. Blood samples were taken from untreated PMR patients, RA patients with active disease and healthy controls (HC) of similar age and gender. To account for known circadian variations in circulating IL-6, samples were taken at a standard time. IL-6 was quantified in plasma and serum using cytometric bead array (CBA) and enzyme-linked immunosorbent assay. The biological activity of the IL-6 was tested for the first time in PMR using a B cell proliferation assay. Using immunostaining and flow cytometry, constitutive intracellular IL-6 was measured in CD3+, CD14+, CD19+, CD123+ and CD11c+ PBMCs. Intracellular IL-6 was also determined following PBMC stimulation in vitro, to determine potential differences in cell responsiveness. Concentrations of secreted IL-6 in the culture supernatants of resting and stimulated PBMC were determined by CBA in parallel cultures. Other cytokines were also quantified in order to examine PMR and RA pathologies more broadly. Finally, the results of the cytokine assays were compared with patient reported severity of fatigue and the four different components of fatigue (emotional, living, physical and cognitive). Circulating IL-6 was significantly elevated above HC in both serum and plasma of PMR and RA patients, and this IL-6 was found to be biologically active. PBMC in all subjects constitutively produced low levels of intracellular IL-6 and very low concentrations of secreted IL-6 in parallel cultures. Overall, responses to in vitro stimulation were variable but no significant differences were observed between PMR, RA and HC samples. Secreted IL-6, in contrast, increased dramatically following stimulation of all cultures, suggesting intracellular staining may not reflect the secretory capability of these cells, but also confirming that there were no differences between PBMC responses of PMR, RA and HC groups. A significant correlation was observed between circulating IL-6 concentrations in PMR and RA patients, and physical fatigue, living fatigue and total fatigue. Broader cytokine analysis demonstrated that IL-6 alone was significantly elevated in PMR patients. Taken together, circulatory IL-6 in active PMR is found to be elevated in the absence of other inflammatory cytokines. It is biologically active and correlates strongly with physical and living aspects of fatigue. Circulating PBMCs are not the source of this elevated IL-6 in PMR patients, suggesting that neutrophils, vascular endothelium or muscle tissue may instead be involved.

Approaches to place and landscape have concerned geographers, at least throughout Modern history. In geographical place and landscape writings, notions of dwelling have been taken up and developed since the 1970s to indicate the lived and practised character of the relationships between human beings and their environment. Dwelling has experienced a controversial history in geography, and bears some negative or limiting connotations: it would be backward-looking, exclusionary, static, nostalgic, and hindered by the idea of rootedness and the authentic/non-authentic life split. This thesis critically considers in what ways seminal dwelling literatures (those written by Martin Heidegger and Tim Ingold) might be problematical and/or enriching for place and landscape writing. In this thesis I argue that the theoretical complexity of seminal dwelling literatures is often overlooked while I also argue that some understandings of the relational, the incomplete, and the contingent are largely missing or problematically conceptualised in seminal dwelling literatures. Taking into account this reflection on the theoretical background of dwelling, the thesis explores possibilities for integrating dwelling in a framework inspired by non-representational theory (NRT). Such links are made in the thesis’ case studies: communities practising (a) long-distance transhumant herding in rural Spain (in which herders and herd journey biennially for about four weeks in response to environmental changes caused by the seasonal cycle), and (b) Easter processions in central Seville (in which brotherhoods celebrate the Resurrection of Jesus Christ). Place and landscape practices are accessed through ethnographical engagements, in which herding - and processional landscapes become the lived contexts for reflection. In the case studies, dwelling is redeveloped through a framework that prioritises posthumanism, relationality and openness, as well as issues of rhythmicity, and nearness (as people care for - and attune to happenings). In long-distance transhumance the rural, the ecological and the practical are privileged, whereas in Easter processions the urban, the spiritual, and to the sheer beauty of life are emphasised. As such, the case studies offer distinct perspectives on the possibilities for developments of dwelling in place and landscape writing, while the case studies share denominators such as journeying, seasonality, embodiment, and practice richness.

The thesis describes the interaction of auxins with membrane fractions prepared from etiolated epicotyl tissue of ‘Pisum Sativum’ seedling. The interaction of auxins with phospholipids was also examined. Two classes of high affinity binding tissue sites were found in the growing region of the epicotyl tissue. Kinetic analysis of the data resulted in dissociation constant values of: K[sub]1=2.2x 10[sup]-7 M, n[sub]1=1.8x10[sup]-10 moles/g fresh wt; K[sub]2=11x10[sup]-7M, n[sub]2=3x10[sup]-10 moles/g fresh wt. These sites were not found in the non-growing region of the pea epicotyl suggesting that they may be involved in the growth process. From the competition studies reported here, it would appear that site 2 showed greater auxin specificity than site 1 and this could be considered a candidate as an auxin receptor. Sucrose gradient fractionation techniques were employed to further separate the two binding sites and it was shown that site 2 binding was associated with fractions rich in plasma membrane while site 1 was associated with the endoplasmic reticulum. Separation of the solubilized sites by gel permeation methods indicated an apparent molecular weight of 42,000 daltons. IAA was shown to complex with the polar head group region of phospholipids, in CDCl[sub]3, although the strength of the complex was rather low (Kd=1.9x10[sup]-2 Molal). The strength of binding was influenced by the polar head groups of the phospholipids, but did not appear to be affected by the fatty acyl chain length. The physiological significances of such interactions are discussed.

Superfluidity is a many-body quantum effect observed for the first time in liquid helium. In the context of modern nanoscience, a natural question is whether superfluidity exists at the nanoscale and if so, under what conditions it occurs. Superfluidity can be probed by means of a torsional pendulum immersed in liquid helium: a decrease in the moment of inertia of the pendulum was observed during the superfluid transition. By replacing the torsional pendulum with a carbonyl sulfide molecule embedded in helium droplets, Grebenev and coworkers explored superfluidity at the nanoscale. They established that 60 4He atoms is the threshold to observe superfluidity. The thermodynamic conditions necessary for this transition could not be ascertained in Grebenev's work since in the helium droplet technique the transition into the superfluid state is impossible to control. One possible way around this experimental limitation is to perform a bulk experiment and embed short-lived helium excimers because all other molecules would freeze. The excimers are in Rydberg states and emit fluorescence sensitive to their environment. In this work, helium excimers have been produced in bulk liquid helium using corona discharges. A wide range of the phase diagram of helium has been probed via fluorescence spectroscopy of Rydberg excimers for the first time: molecular transitions in gaseous, supercritical, vapor and normal liquid phases have been studied systematically. Depending on the thermodynamic conditions, sharp as well as broadened spectra have been observed. The linewidths and lineshifts of a transition of interest have been interpreted on the basis of a model that considers emission from two kinds of excimer: on the one hand, excimers embedded in voids and fully solvated in liquid helium exhibiting hindered rotation, and on the other hand, excimers residing in larger gas pockets within the liquid helium, exhibiting free rotation. The relative contributions of each species of excimer have been estimated in a ratio of approximately 1:5. Hindered transitions were identified for pressures and temperatures in the vapor phase, before helium liquefies. These points in the phase diagram show the formation of clusters between excimers and ground-state helium atoms, indicating that the He_2 -He interaction is stronger than that of He-He.

Air pollution has a significant detrimental effect on human/ecosystem health and is an important issue for a rapidly urbanising world. Anthropogenic NOx (NO and NO2) emissions have a range of health and environmental impacts. Reliable measurements of NOx are used to inform a range of science and policy goals. Satellite observations of tropospheric NO2 give a synoptic view of global and regional air pollution and are essential to constraining NOx emission estimates. However, coarse spatio-temporal resolution limits their utility to analyse urban pollution. The Compact Air Quality Spectrometer (CompAQS), a UV-VIS hyperspectral instrument, was developed to provide high spatial resolution imaging of urban pollution. The work described in this thesis covers the development of alternative retrieval algorithms of tropospheric NO2 for CompAQS. A variant on the Differential Optical Absorption Spectroscopy (DOAS) technique was developed using unpolluted Earthshine reference spectra, and was tested using modelled and operational satellite spectra. Tropospheric columns retrieved with this technique agreed well with operational products (r2 = 0:85), particularly over heavily polluted regions (r2 = 0:96). A neural network retrieval employing only several wavelengths was also developed and tested on modelled spectra, which demonstrated low fitting errors ( < 10%) even with noisy data. Air mass factors were calculated to correct the data for other influences (e.g. surface albedo) for a CompAQS demonstrator test flight campaign over Leicester in February 2013. While CompAQS could resolve high-resolution pollution features, the DOAS fit uncertainty dominated the retrieval error (37%), indicating that better instrument calibration would be required to improve its eventual use as a satellite instrument. The retrieval algorithms demonstrated in this work could be tailored to support satellite adaptations of CompAQS. However, further research investigating the reliability and resolution of assumed a priori information (e.g. the NO2 vertical profile) will be required to produce a full mission study concept.