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Brown, and brown-like, adipose tissue provides a potential target for treatments to increase energy expenditure and the consumption of lipids and glucose. In humans, active depots have been shown to persist into adulthood where, previously, they were thought to atrophy in childhood. Due to the presence of uncoupling protein-1 (UCP1) within the inner mitochondrial membrane, brown adipocytes possess the capability to prevent the energy released during cellular respiration from being stored as adenosine triphosphate, instead allowing the energy to be released as heat. Since heat energy is, eventually, dissipated from the body, the result is energy expenditure. Why the body possesses such a tissue specifically designed to waste energy is explained by the benefit conferred by the ability to produce heat on demand, in response to cold challenge. The major alternative heat generating method, shivering, can respond instantly but produces vastly less heat for the same effort. Beyond the acute shivering response, which cannot be maintained for prolonged periods, brown adipose tissue is an essential contributor to thermal homeostasis. Brown adipose tissue is innervated by the sympathetic nervous system (SNS), acting on B3-adrenoreceptors to stimulate intracellular lipolysis, increased free fatty acids (as well as glucose uptake), upregulation of UCP1 and, hence, heat production. This process is modulated both at the level of the hypothalamic SNS activity and at the intracellular level by thyroid hormones. Thyroid hormones act on the hypothalamus to increase brown adipose tissue stimulation and the biologically active thyroid hormone, triiodothyronine, concentrations are increased within the BAT cell by conversion from the inactive form, thyroxine, by 5'deiodinase-2. To examine the efficacy of potential stimulators, an effective way of measuring brown adipose tissue activity is required. Positron emission tomography-computed tomography (PET-CT) measures glucose uptake and therefore, under cold stimulation, has allowed brown adipose tissue activity to be quantified using the surrogate measure of glucose uptake and for brown adipose tissue volumes to be calculated. However, PET-CT is unable to measure brown adipose tissue in the fed state due to glucose uptake of muscles, and the radiation exposure means it is not suitable for use in children, large studies or repeat measurements. It is of particular interest to understand the attributes of brown adipose tissue in children since this is the period of maximal brown adipose tissue activity and the time in which physiological parameters are established with lifelong effects. Since the major output of BAT is heat, attempts have been made to measure the heat that is transferred from the BAT depot to the skin either by use of thermocouples, such as iButtons™, or infrared thermography. These methods aim to address some of the limitations of PET-CT as they are non-invasive, readily available and do not expose the participant to ionising radiation. Furthermore, they directly measure the major output of BAT activity, i.e. heat, rather than measuring an input, e.g. glucose uptake, which may not always reflect the activity of the tissue. The thesis presented here aimed to validate IRT against PET-CT for the measurement of BAT activity and to improve the efficiency of IRT image analysis by automation before using IRT to demonstrate the effects of a) glucose dysregulation and b) thyroid hormone dysfunction on human BAT in vivo. While infrared thermography was clearly able to demonstrate a supraclavicular hotspot, it was questioned whether this truly reflected BAT and whether changes in the thermal signature were indicative of BAT activation as many other factors influence skin temperature. In addition, image analysis was limited by the time-intensive process of manual image analysis. I, therefore, designed a semi-automated method of image analysis, coded using MATLAB™ by a colleague in the University's Faculty of Engineering. This method was 86% faster than the previous method, without any increase in variation on repeated analysis. I then undertook an analysis of thermal images and PET-CT scans from the same individuals and compared them. Following image alignment, the "hotspot" of glucose uptake on PET-CT overlaps with the thermal "hotspot" from infrared thermography and glucose uptake was correlated well with changes in the temperature of the skin overlying the BAT depot. Having established and validated the image analysis method, a series of cold-water swimmers were imaged before and after their event. Exposure to this mixed maximal stimulation showed dramatic preservation of the BAT hotspot compared to the sternal reference region (3.5±1.6°C higher post-swimming compared to baseline), although further work is needed to identify the relative effects of the different stimulation components. I have then shown that girls with autoimmune hypothyroidism have reduced increase in supraclavicular temperature relative to a sternal reference point compared to healthy controls (hypothyroid: 0.1±0.1°C; control: 0.2±0.2°C; p = 0.04) yet, within those participants with hypothyroidism, TSH concentration was associated with increased relative supraclavicular temperatures (r = 0.7, p = 0.01). In children with diabetes compared to healthy controls stimulated relative supraclavicular temperatures were lower (diabetes: 35.0±0.6°C; control: 35.4±0.5°C; p = 0.04) and a smaller change in relative supraclavicular temperature following stimulation, after adjusting for BMI (diabetes: 0.1±0.1°C; control: 0.2±0.2°C; p = 0.03). In these studies, data was not available on thyroid function test results or glycaemic status for healthy volunteers which future work should look to address in addition to measuring and controlling for pubertal status. In conclusion, this thesis demonstrates that infrared thermography is a valid and reproducible way to measure BAT activity in the non-invasive and affordable way. The increase in image analysis rate provides the opportunity for future work to look at larger groups, longer imaging periods or increased image frequency even to the level of thermal videos and, thereby, reveal finer detail about the mechanisms and potential stimulators. Further advances in image analysis techniques will aim to fully automate the process. In children with diabetes, there is an indication of a similar reduction in BAT activity, potentially due to the differences between exogenous and endogenous insulin, such as endogenous insulin not being suppressed by sympathetic nervous system activity. Further work is also required to better understand the complex interaction between BAT and the thyroid-axis with many questions remaining. In girls with autoimmune thyroid disease, BAT activity appears to be reduced but TSH appears to stimulate BAT activity suggesting that the disease process itself may have a negative effect on BAT response but this may be mitigated by high TSH levels.

Formaldehyde is a highly toxic molecule; despite this, it is produced in the cells of all living organisms as a by-product of metabolic pathways. Consequently, several pathways have evolved throughout life in order to detoxify cellular formaldehyde. These pathways need to be regulated within the cell and this study sets out to determine how these pathways are regulated in particular bacteria. Several approaches are taken to achieve this. Known or predicted transcription factors that regulate formaldehyde detoxification pathways from particular organisms are considered. These proteins are called FrmR (E. coli), HxlR1 (Bacillus subtilis), and HxlR2 (Bacillus Cereus). The transcription factors are cloned and purified using molecular biology techniques. The proteins are subject to biophysical characterisation i.e. size and secondary structure composition. Additionally, the X-ray crystal structure of HxlR2 is determined and significant progress is made towards determining the structure of FrmR. Interactions of these transcription factors towards their target DNA sequences are studied along with the effect that formaldehyde has on these interactions. A reporter system is constructed that enables the behaviour of FrmR to be studied in vivo. Residues that are likely to play important roles in DNA recognition by this regulator are identified. Additionally, this reporter system identifies a residue that is essential for formaldehyde sensing by this protein. Overall, some significant insights into how these transcription factors carry out their biological function are established.

Multirobot control architectures often require robotic tasks to be well defined before allocation. In complex missions, it is often difficult to decompose an objective into a set of well defined tasks; human operators generate a simplified representation based on experience and estimation. The result is a set of robot roles, which are not best suited to accomplishing those objectives. This thesis presents an alternative approach to generating multirobot control algorithms using task abstraction. By carefully analysing data recorded from similar systems a multidimensional and multilevel representation of the mission can be abstracted, which can be subsequently converted into a robotic controller. This work, which focuses on the control of a team of robots to play the complex game of football, is divided into three sections: In the first section we investigate the use of spatial structures in team games. Experimental results show that cooperative teams beat groups of individuals when competing for space and that controlling space is important in the game of robot football. In the second section, we generate a multilevel representation of robot football based on spatial structures measured in recorded matches. By differentiating between spatial configurations appearing in desirable and undesirable situations, we can abstract a strategy composed of the more desirable structures. In the third section, five partial strategies are generated, based on the abstracted structures, and a suitable controller is devised. A set of experiments shows the success of the method in reproducing those key structures in a multirobot system. Finally, we compile our methods into a formal architecture for task abstraction and control. The thesis concludes that generating multirobot control algorithms using task abstraction is appropriate for problems which are complex, weakly-defined, multilevel, dynamic, competitive, unpredictable, and which display emergent properties.

In cognitive linguistic frameworks, metonymy is seen as one of the primary mechanisms of semantic change. While it is acknowledged that conceptual metonymies are cross-linguistically variable, little systematic research has explored diachronic variability in the metonymies that are frequently exploited in a language and that contribute to lexical semantic shifts. Much is still unknown about how metonymies arise, develop, and become entrenched in linguistic constructions. This study considers metonymic links between elements of three semantic frames in French: SPENDING, ATTRIBUTING CAUSE, and REVEAL SECRET. I annotated the syntactic realization of these semantic frame elements in sentences containing 66 lexical units evoking these frames found in a diachronic corpus spanning from the 12th to the 20th centuries. Metonymies in the REVEAL SECRET and SPENDING frames were increasingly exploited over time, beginning in particular contexts where the metonymy serves a specific communicative purpose and gradually expanding to other contexts and lexical units. Other metonymies in the ATTRIBUTING CAUSE frame and also in the SPENDING frame were observed less in later centuries. A general trend is the use or non-use of metonymy to shift focus away from semantic roles referring to individuals, tied to a shift in French writing towards essays and other genres where depersonalization is useful. The results support the hypothesis that semantic change occurs at the level of the frame or domain, and only secondarily at the individual lexical level. They also offer insight into how cross-linguistic or cross-dialectal variation in the use of figurative language might arise.

Collaborative robots and current human-robot interaction systems, such as exoskeletons and teleoperation, are key technologies with profiles that make them likely security targets. Without sufficient protection, these robotics technologies might become dangerous tools that are capable of causing damage to their environments, increasing defects in work pieces and harming human co-workers. As robotics is a critical component of the current automation drive in many advanced economies, there may be serious economic effects if robot security is not appropriately handled. The development of suitable security for robots, particularly in industrial contexts, is critical. Collaborative robots, exoskeletons and teleoperation are all examples of robotics technologies that might need close collaboration with humans, and these interactions must be appropriately protected. There is a need to guard against both external hackers (as with many industrial systems) and insider malfeasance. Only authorised users should be able to access robots, and they should use only those services and capabilities they are qualified to access (e.g. those for which they are appropriately cleared and trained). Authentication is therefore a crucial enabling mechanism. Robot interaction will largely be ongoing, so continuous rather than one-time authentication is required. In robot contexts, continuous biometrics can be used to provide effective and practical authentication of individuals to robots. In particular, the working behaviour of human co-workers as they interact with robots can be used as a means of biometric authentication. This thesis demonstrates how continuous biometric authentication can be used in three different environments: a direct physical manipulation application, a sensor glove application and a remote access application. We show how information acquired from the collaborative robot's internal sensors, wearable sensors (similar to those found in an exoskeleton), and teleoperated robot control and programming can be harnessed to provide appropriate authentication. Thus, all authentication uses data that are collected or generated as part of the co-worker simply going about their work. No additional action is needed. For manufacturing environments, this lack of intrusiveness is an important feature. The results presented in this thesis show that our approaches can discriminate appropriately between users. We believe that our machine learning-based approaches can provide reasonable and practical solutions for continually authenticating users to robots in many environments, particularly in manufacturing contexts.

Advances in the synthesis of materials and device structures have accentuated the need to understand nanoscale electronic structure and its implications. Scanning probe microscopy offers a rich variety of highly spatially accurate techniques that can further our understanding of the interactions that occur in nanoscale semiconductor materials and devices. The promising nitride semiconductor materials system suffers from perturbations in local electronic structure due to crystallographic defects. Understanding the electronic properties and physical origin of these defects can be invaluable in mitigating their impacts or eliminating them all together. In the second chapter of this dissertation, scanning capacitance microscopy (SCM) is used to characterize local electronic structure in a-plane n-type gallium nitride. Analysis reveals the presence of a linear, positively charged feature aligned along the direction which likely corresponds to a partial dislocation at the edge of a stacking fault. In the third chapter, conductive atomic force microscopy is used to determine the effects of Ga/N flux on the conductive behavior of reverse-bias leakage paths in gallium nitride grown by molecular beam epitaxy (MBE). Our data reveal a band of fluxes near Ga/N ̃ ̃1 for which these pathways cease to be observable. These observations suggest a method for controlling the primary source of reverse-bias Schottky contact leakage in n-type GaN grown by MBE. A deeper understanding of the interaction between macro-scale objects and nanoscale electronic properties is required to bring the exciting new possibilities that semiconductor nanowires offer to fruition. In the fourth chapter, SCM is used to examine the effects of micron-scale metal contacts on carrier modulation and electrostatic behavior in indium arsenide semiconductor nanowires. We interpret a pronounced dependence of capacitance spectra on distance between the probe tip and nanowire contact as a consequence of electrostatic screening of the tip-nanowire potential difference by the large metal contact. These results provide direct experimental verification of contact screening effects on the electronic behavior of nanowire devices and are indicative of the importance of accounting for the effect of large-scale contact and circuit elements on the characteristics of nanoscale electronic devices

This study examined the relationship between the preferred leadership styles, the levels of computer anxiety, and the selected personal attributes of sex, age, and computer training upon the computer use of West Virginia public school principals. A one shot case study design was used to examine the relationships. Three instruments the Leadership Behavior Description Questionnaire-Self (LDBQ-Self), the Computer Anxiety Rating Scale-C (CARS-C), and the Levels of Computer Use (LCU) survey, along with a cover letter and a short personal attribute questionnaire were mailed to randomly selected sample of 160 West Virginia principals. Responses were received from 93 (58.1%) of the principals. Data analysis revealed a statistically significant relationship between the principals' levels of computer anxiety and their levels of computer use. A statistically significant relationship was also discovered between the principals preferred leadership style of consideration and the principals' level of computer anxiety. It was also found that a larger percentage of female principals were functioning at the higher computer usage level of integration than male principals. This study provided mixed results. The significant negative relationships found between the principals' computer anxiety and computer use and between the principals' leadership style of consideration and computer anxiety confirmed earlier research. However, the absence of a significant relationship between the principals' leadership style and computer use, the principals' age and computer use, the principals' sex and computer use, and the principals' computer training and computer use were contrary to earlier research findings. The results of this study may be beneficial to educational leaders at the local, and state levels as well as higher education in the planning for, and implementation of computers in schools. The results of this study may also be of use in the planning of principal inservice.

This thesis is concerned with the emergence of communication in arti cial agents as an integrated part of a more general developmental progression. We demonstrate how early gestural communication can emerge out of sensorimotor exploration before moving on to linguistic communication. We then show how communicative abilities can feed back into more general motor learning. We take a cumulative developmental approach, with two di erent robotic platforms undergoing a series of psychologically inspired developmental stages. These begin with the robot learning about its own body's capabilities and limitations, then on to object interaction, the learning of proto-imperative pointing and early language learning. Finally this culminates in more complex object interaction in the form of learning to build stacks of objects with the linguistic capabilities developed earlier being used to help guide the robot's learning. This developmental progression is supported by a schema learning mechanism which constructs a hierarchy of competencies capable of dealing with problems of gradually increasing complexity. To allow for the learning of general concepts we introduce an algorithm for the generalisation of schemas from a small number of examples through parameterisation. Throughout the robot's development its actions are driven by an intrinsic motivation system designed to mimic the play-like behaviour seen in infants. We suggest a possible approach to intrinsic motivation in a schema learning system and demonstrate how this can lead to the rapid unsupervised learning of both speci c experiences and general concepts.