The desktop publishing revolution of the 1980s is currently repeating itself in 3D, referred to as desktop manufacturing. Online services such as Shapeways have become available, making personalized manufacturing on cutting edge additive manufacturing (AM) technologies accessible to a broad audience. Affordable desktop printers will soon take over, enabling people to fabricate / Engineering and Applied Sciences

The Hypothalamus-Pituitary-Adrenal axis (HPA-axis) with its end product cortisol mediates the physiological response to stress thereby promoting mobilization of energy. The cortisol levels follow a diurnal rhythm with a distinct awakening response. Regulation of the HPA-axis differs among persons with certain psychiatric disorders when compared with controls. Some reports concern Attention-Deficit/Hyperactivity Disorder (ADHD) but findings are inconclusive. The main aim of the present thesis was to investigate diurnal levels of saliva cortisol in school aged children with ADHD and age matched non-affected comparisons, also taking early adversity, perceived stress and ADHD-medication into consideration. Children with ADHD had lower cortisol levels at awakening, 30 minutes later and before going to bed than comparisons. When the study group was split into three different age groups similar results were found only for children above 10 years of age. Within the ADHD group, subtype of ADHD or co-occurring symptoms did not affect the cortisol levels. Furthermore, children in the ADHD group had to a higher degree been exposed to foetal and childhood psychosocial adversity than comparisons. Since exposure to early adversity has been associated with both ADHD and HPA-axis functioning, such exposures could theoretically explain the low cortisol levels in ADHD via early programming of the HPA-axis. However, no relation was found between exposures to psychosocial adversity and diurnal cortisol levels. Neither did continuous medication with stimulants or atomoxetine explain the low cortisol levels. Possibly, medication may rather increase the levels. Finally, children with ADHD scored higher on perceived stress, measured by the Pressure-Activation-Stress (PAS) scale, than the comparison group. Female sex was also associated with higher stress in both groups, as well as increasing age in the comparison group. As with psychosocial adversity, no association was found between the higher PAS-scores and the lower cortisol levels, indicating the complexity of the stress regulating system. The results indicate a down-regulated or displaced HPA-axis with lower cortisol levels in children with ADHD. Stress related fragility – with more exposure to early stressors, higher perceived stress and lower diurnal cortisol levels – seem to accompany ADHD during childhood.

Despite recent research advances, there are still several common medical conditions whose underlying mechanisms are poorly understood. In conditions with few or diffuse physical findings, it can be difficult to diagnose and determine the state of the condition and its effects on working ability or performance, and the health care practitioners have to rely on the patient’s self-reports. Identification of objective measurements that are sensitive enough to aid in diagnosis or determination of the state of these conditions would thus be valuable. Psychophysiological measurements are generally non-invasive and have the potential to serve as such diagnostic or prognostic tools. In this thesis, psychophysiological reactions to different stressors were recorded in two selected medical conditions; namely motion sickness and chronic trapezius myalgia (musculoskeletal pain). These subjective conditions are unpleasant, unwanted and apparently serve no survival purpose. It is therefore important to elucidate any physical findings associated with them to, eventually, find new means to prevent the development of these conditions or to ameliorate symptoms. The overall aim of the thesis was to explore the development of psychophysiological responses to stressors in relation to performance and subjective reports in healthy individuals and in women with chronic trapezius myalgia. More in detail, the purpose was to identify psychophysiological responses that could provide information about the mechanisms behind, or serve as candidates for characterization of motion sickness and chronic trapezius myalgia, respectively. Responses to motion sickness, triggered by optokinetic stimulation, were studied in healthy individuals, whereas responses to repetitive low-force work and psychosocial stress were studied in women with chronic trapezius myalgia and in pain-free controls. In both medical conditions, the psychophysiological responses were accompanied by subjective reports. The effects of motion sickness on two different aspects of memory performance were tested during exposure to optokinetic stimulation. In the studies of chronic trapezius myalgia, psychophysiological responses were also related to health status, i.e., being a patient or a pain-free control and measurements of pain intensity, psychological symptoms, sleep-related problems and quality of life. The psychophysiological responses to optokinetic stimulation were inconclusive. Moderate levels of motion sickness did not affect memory performance, whereas decreased short term memory performance was seen in subjects reporting high levels of motion sickness. The autonomic responses and stress hormone secretion in response to low-force repetitive work and psychosocial stress in the chronic trapezius myalgia group were similar to those of the pain-free controls. However, muscle activity in the trapezius muscle was generally higher in the chronic trapezius myalgia group. There were indications of negative psychological states being related to a slower response and lower circadian variations of stress hormone secretion. With the present methods, it was possible to measure general stress responses but none of the measurements showed sufficient specificity to serve as predictors or indicators of motion sickness and chronic musculoskeletal pain, respectively. Summarizing, I cannot objectively measure how you feel; I still have to rely on your description of your condition.

Elongation of the vertebrate rostrocaudal axis depends on localised populations of axial progenitors. Previous work has demonstrated the presence of Neuromesodermal (NM) progenitors that behave as multipotent stem cells, which contribute to the neurectoderm and mesoderm throughout axis elongation. They have been localised to the Node-­‐Streak Border (NSB) in the primitive streak region, and the Chordoneural Hinge (CNH) in its descendant, the tail bud. At primitive streak stages, the Caudal Lateral Ectoderm (CLE) on either side of the primitive streak itself is also fated for neurectoderm and mesoderm. However, fate mapping studies in mouse and chick have suggested that these progenitors are more transitory than those in the NSB and CNH, leading to the idea that two different types of progenitor cell exist in the primitive streak region; long-­‐term (stem cell-­‐like) and transient progenitors. In this thesis, I have examined the potency of the CLE cells by heterotopically grafting them into the NSB. Anterior CLE cells are exquisitely sensitive to their position and differentiate predominantly as neurectoderm, mesoderm, or both, depending on their exact location in the NSB. Most significantly, their descendants are retained in the CNH, indicating that CLE cells show equal potential to NSB progenitors on transplantation to the border environment. The relationship between fate and potency within the streak stage embryo suggest a mechanism by which stem cells are maintained not only by their intrinsic stem cell program, but are also influenced by their location. Furthermore, I have investigated the expression of candidate markers of NM-­‐progenitors, and have found that the combined expression of Sox2 and T genes in the progenitor area coincides with observed NM-­‐potency, and could serve as a marker for this stem cell population. Over time, axial elongation comes to a halt and NM-­‐progenitors are thereafter not longer active. It is still unclear how exactly this process occurs and specifically whether axial elongation ceases because NM progenitors are eliminated. I have investigated the events occurring immediately before the end of axial elongation. Morphological and gene expression analysis shows that apoptosis reaches a peak only after the complete axis has been laid down, and is not dramatically elevated in the progenitors themselves before that. In order to test signalling pathways that lead to progenitor maintenance, I have developed an in vitro tail growth assay that recapitulates in vivo development, as measured by several morphometric criteria. I show that, even though FGF signalling is critical for most cells in the tail bud including NM-­‐progenitors, it is not sufficient for NM-­‐ progenitor maintenance. In contrast, exposing tail buds to elevated Wnt/β-­‐catenin signalling does prolong the lifetime of NM-­‐progenitors in the ageing tail bud, as judged by the presence of Sox2-­‐T double-­‐positive cells. In this regard we have found that the time of cessation coincides with the disappearance of Sox2-­‐T double-­‐positive cells, the disappearance of Wnt3a and concomitant neuralisation of the progenitor region. This data suggest an important governing role for Wnt signalling in both maintenance and fate decision of NM progenitors. Thus the disappearance of Wnt signalling in the tail bud over time could well be the main reason for triggering the halt of caudal elongation.

Tidal currents can be used as a predictable source of sustainable energy, and have the potential to make a useful contribution to the energy needs of the UK and other countries with such a resource. One of the technologies which may be used to transform tidal power into mechanical power is a vertical axis turbine, the hydrodynamic analysis of which this thesis is concerned with. The aim of this analysis is to gain a better understanding of the power transformation process, from which position there is the possibility of improving the conversion efficiency. A second aim is to compare the results from different modelling approaches. Two types of mathematical modelling are used: a basic blade element momentum model and a more complex Reynolds-averaged Navier Stokes (RANS) model. The former model has been programmed in Matlab by the present author while the latter model uses a commercial computational fluid dynamics (CFD) code, ANSYS CFX. This RANS model uses the SST k-! turbulence model. The CFD analysis of hydrofoils (equally airfoils), for both fixed and oscillating pitch conditions, is a significant proportion of the present work. Such analysis is used as part of the verification and validation of the CFD model of the turbine. It is also used as input to the blade element momentum model, thereby permitting a novel comparison between the blade element momentum model and the CFD model of the turbine. Both types of turbine model were used to explore the variation in turbine efficiency (and other factors) with tip speed ratio and with and without an angle of attack limiting variable pitch strategy. It is shown that the use of such a variable pitch strategy both increases the peak efficiency and broadens the peak. The comparison of the results from the two different turbine modelling approaches shows that when the present CFD hydrofoil results are used as input to the blade element model, and when dynamic effects are small and the turbine induction factor is low, there is generally good agreement between the two models.

The affective disorders (anxiety and depression) are common psychiatric disorders that primarily involve disturbances in mood and represent the second leading source of disease burden world-wide. A wide base of evidence supports a significant genetic contribution to these disorders. Polymorphic variation in the promoter region (5-HTTLPR) of the human serotonin transporter (hSERT) gene, which leads to a life-long alteration in serotonin transporter (SERT) expression and functioning, has been implicated in the aetiology of both anxiety and depression. Despite the strong evidence implicating a role for this polymorphism in affective psychopathology the underlying mechanism by which genetically determined SERT bioavailability influences affective functioning are not understood. In these studies I attempt to elucidate the alterations in cerebral, serotonin (5-HT) system and hypothalamo-pituitary-adrenal (HPA) axis functioning which may relate to the effect of the 5-HTTLPR on affective functioning by characterising these parameters in an animal model of genetically increased SERT expression (hSERT over-expressing mice; hSERT OVR). Furthermore, as gender influences both the likelihood of developing affective disorders and the impact of the 5-HTTLPR on affective functioning, with a greater effect being observed in females than in males, we characterise these parameters in mice of both genders. The data presented in this thesis demonstrate that the life-long increase in SERT bioavailability present in hSERT OVR mice produces profound alterations in cerebral, serotonin system and HPA axis functioning. Furthermore, the influence of increased SERT expression upon cerebral and serotonin system functioning is greater in females than in males. Additionally, a number of sexually dimorphic variations in serotonin system functioning were identified. Thus this thesis extends the currently available information regarding the underlying mechanisms by which gender and a life-long alteration in SERT expression may influence the risk of affective psychopathology.

International Telemetering Conference Proceedings / October 25-28, 1993 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The first telemetry tracking system was desired in 1959 for the space program. Cost was of little concern. The tracking technique used was 3 channel monopulse which is still today, after all these years, the optimum in performance for any type of tracking requirement. Telemetry tracking really got off the ground in the early 1970's with the move from P-Band to S-Band for telemetry. In the design of early tracking systems, performance was on the top of the list, and cost was on the bottom of the list in establishing the design criteria. By the beginning of the 1980's cost was approaching performance in importance. Today, with the demise of the cold war and a considerable reduction in global threats coupled with the state of the world economy, cost has now reached the top of the list. The cost of a telemetry tracking system can be reduced by more than a factor of two by going to a single axis tracking technique. The lowest cost single axis approach heretofore has been the use of a cosecant squared (CSC²) distribution. To improve the efficiency of a single axis system and increase the overhead coverage capability, the use of a dual beam antenna has been widely used as another type of single axis approach. The dual beam technique involves additional costs since two tracking antennas are required. Except for satellite tracking, almost all telemetry tracking is performed at low elevation angles and, like it or not, multipath is there. The multipath fade varies from a few dB, to over 20 dB depending upon the reflecting terrain. Most general purpose systems should be designed for at least a 10 dB multipath fade. For all telemetry tracking applications, the multipath effect is completely negligible at elevation angles greater than 10 degrees. The Augustin-Sullivan Distribution, in effect, fades away the multipath margin as the multipath effect decreases. Because of the multipath phenomenon, an antenna beam should not be shaped at the one dB point as is the case with a CSC² distribution, but only needs to be shaped from somewhere between the 15 - 20 dB level based on the mission requirements. This involves a gain reduction from a pencil beam on the order of 1/2 dB or less, rather than the 3 dB reduction associated with the CSC² distribution. The Augustin-Sullivan distribution does not start shaping the beam until shaping is retired, and shapes the beam for constant altitude coverage from the horizon to zenith. For the first time, coverage is provided from the peak of the beam to directly overhead with a single antenna and a single axis rotator. When GPS information is available from the tracked vehicle, the Augustin-Sullivan distribution, with a single axis rotator and using the GPS-TRAK technique, results in the lowest possible cost alternate to autotracking.

The Richard F. Caris Mirror Lab at the University of Arizona is responsible for production of the eight 8.4 m segments for the primary mirror of the Giant Magellan Telescope, including one spare off-axis segment. We report on the successful casting of Segment 4, the center segment. Prior to generating the optical surface of Segment 2, we carried out a major upgrade of our 8.4 m Large Optical Generator. The upgrade includes new hardware and software to improve accuracy, safety, reliability and ease of use. We are currently carrying out an upgrade of our 8.4 m polishing machine that includes improved orbital polishing capabilities. We added and modified several components of the optical tests during the manufacture of Segment 1, and we have continued to improve the systems in preparation for Segments 2-8. We completed two projects that were prior commitments before GMT Segment 2: casting and polishing the combined primary and tertiary mirrors for the LSST, and casting and generating a 6.5 m mirror for the Tokyo Atacama Observatory.

It has been shown that the cosmic censorship conjecture holds for polarized Gowdy spacetimes. In the more general, unpolarized case, however, the question remains open. It is known that cylindrically symmetric dust can collapse to form a naked singularity. Since Gowdy universes comprise gravitational waves that are locally cylindrically symmetric, perhaps these waves can collapse onto a symmetry axis and create a naked singularity. It is known that in the case of cylindrical symmetry, event horizons will not form under gravitational collapse, so the formation of a singularity on the symmetry axis would be a violation of the cosmic censorship conjecture.To search for cosmic censorship violation in Gowdy spacetimes, we must have a better understanding of their singularities. It is known that far from the symmetry axes, the spacetimes are asymptotically velocity term dominated, but this property is not known to hold near the axes. In this thesis, we take the first steps toward understanding on and near axis behavior of Gowdy spacetimes with space-sections that have the topology of the three-sphere. Null geodesic behavior on the symmetry axes is studied, and it is found that in some cases, a photon will wrap around the universe infinitely many times on its way back toward the initial singularity.

This thesis is based in the research area of Design for Sustainable Behaviour (DfSB), a field which seeks to reduce the social and environmental impact of products in the use phase of their life cycle. There has been significant theoretical development in this area in recent years, leading to a proliferation of intervention strategies and design methodologies. However, there has been a recognised lack of a reliable means of selecting which intervention strategy to use in a given situation, and a lack of real world intervention case studies generating measurable medium-to-long term reductions in energy consumption. Addressing these gaps was a central focus of this research. This thesis documents four distinct research phases; an extensive literature review, an in-depth user study of existing energy consuming behaviours and motivations, the development and trialling of design interventions, and the evaluation of the generated theories as a tool for designers. Literature on domestic energy consumption, human behaviour, and approaches to changing behaviour was reviewed to establish the current level of thinking and to identify opportunities for further research. This guided the undertaking of the user study with a number of families in the East Midlands of the UK, which illuminated the relevant motivational goals, and highly routinized nature, displayed in many energy consuming behaviours. Over the course of this phase of the research journey a new conceptual model of behaviour in context was developed, and refined to create the Behavioural Intervention Selection Axis (BISA). These theoretical developments were then applied to the generation of DfSB intervention concepts, one of which was selected and developed to a functional prototype stage. These prototypes were trialled in situ in family homes for an extended period, and achieved a significant change in behaviour and related energy consumption. Further evaluation of the BISA as a tool to guide designers was performed through a series of workshops with design students, which ascertained its usefulness in this respect. Both the intervention development and trialling and the design workshops showed the conceptual model and BISA to be successful in providing designers with a reliable and useful means of selecting appropriate intervention strategies to change behaviour. In addition the intervention trial provided a wealth of qualitative insight into the way in which DfSB can effect behaviour, and the range of new motivational goals it can engender.