502 resultados para peer reviewed research outputs
Resumo:
The topic of this thesis is impulsivity. The meaning and measurement of impulse control is explored, with a particular focus on forensic settings. Impulsivity is central to many areas of psychology; it is one of the most common diagnostic criteria of mental disorders and is fundamental to the understanding of forensic personalities. Despite this widespread importance there is little agreement as to the definition or structure of impulsivity, and its measurement is fraught with difficulty owing to a reliance on self-report methods. This research aims to address this problem by investigating the viability of using simple computerised cognitive performance tasks as complementary components of a multi-method assessment strategy for impulse control. Ultimately, the usefulness of this measurement strategy for a forensic sample is assessed. Impulsivity is found to be a multifaceted construct comprised of a constellation of distinct sub-dimensions. Computerised cognitive performance tasks are valid and reliable measures that can assess impulsivity at a neuronal level. Self-report and performance task methods assess distinct components of impulse control and, for the optimal assessment of impulse control, a multi-method battery of self-report and performance task measures is advocated. Such a battery is shown to have demonstrated utility in a forensic sample, and recommendations for forensic assessment in the Irish context are discussed.
Resumo:
The global proportion of older persons is increasing rapidly. Diet and the intestinal microbiota independently and jointly contribute to health in the elderly. The habitual dietary patterns and functional microbiota components of elderly subjects were investigated in order to identify specific effector mechanisms. A study of the dietary intake of Irish community-dwelling elderly subjects showed that the consumption of foods high in fat and/or sugar was excessive, while consumption of dairy foods was inadequate. Elderly females typically had a more nutrient- dense diet than males and a considerable proportion of subjects, particularly males, had inadequate intakes of calcium, magnesium, vitamin D, folate, zinc and vitamin C. The association between dietary patterns, glycaemic index and cognitive function was also investigated. Elderly subjects consuming ‘prudent’ dietary patterns had better cognitive function compared to those consuming ‘Western’ dietary patterns. Furthermore, fully-adjusted regression models revealed that a high glycaemic diet was associated with poor cognitive function, demonstrating a new link between nutrition and cognition. An extensive screening study of the elderly faecal-derived microbiota was also undertaken to examine the prevalence of antimicrobial production by intestinal bacteria. A number of previously characterised bacteriocins were isolated (gassericin T, ABP-118, mutacin II, enterocin L-50 and enterocin P) in this study. Interestingly, a Lactobacillus crispatus strain was found to produce a potentially novel antimicrobial compound. Full genome sequencing of this strain revealed the presence of three loci which exhibited varying degrees of homology with the genes responsible for helveticin J production in Lb. helveticus. An additional study comparing the immunomodulatory capacity of ‘viable’ and ‘non-viable’ Bifidobacterium strains found that Bifidobacterium-fermented milks (BFMs) containing ‘non-viable’ cells could stimulate levels of IL-10 and TNF-α in a manner similar to those stimulated by BFMs containing ‘viable’ cells in vitro.
Resumo:
Renal failure (RF) is associated with an over activation of the sympathetic nervous system. The aim of this thesis was to investigate the hypothesis that as the kidney progresses into RF there is an inappropriate and sustained activation of renal afferent nerves which results in a dysregulation of basal RSNA and reflexly controlled RSNA by the high and low pressure baroreceptors. Baroreflex gain curves for both RSNA and HR were generated in control and RF rats. This study clearly showed a blunted high-pressure baroreflex in RF rats, an impairment which was almost completely corrected by bilateral renal denervation. The integrity of the low-pressure cardiopulmonary receptors to inhibit RSNA was investigated using acute saline volume. Again, a blunted reflex sympatho-inhibition of RSNA was observed, which was corrected by renal denervation. Finally a functional study to examine how the renal excretory response to volume expansion differed in RF was carried out. This study revealed an impairment of the low-pressure baroreflex control of the sympathetic outflow. The result of these studies suggest that cisplatin induced RF initiates a neural signal from within the kidney, which over rides the normal reflex regulation of RSNA by the high and low – pressure baroreceptors and that this impairment in function can be normalised by renal denervation. This raises further questions as to the mechanisms involved in the afferent over activation arising from the diseased kidneys.
Resumo:
Both the emission properties and the evolution of the radio jets of Active Galactic Nuclei are dependent on the magnetic (B) fields that thread them. A number of observations of AGN jets suggest that the B fields they carry have a significant helical component, at least on parsec scales. This thesis uses a model, first proposed by Laing and then developed by Papageorgiou, to explore how well the observed properties of AGN jets can be reproduced by assuming a helical B field with three parameters; pitch angle, viewing angle and degree of entanglement. This model has been applied to multifrequency Very Long Baseline Interferometry (VLBI) observations of the AGN jets of Markarian 501 and M87, making it possible to derive values for the helical pitch angle, the viewing angle and the degree of entanglement for these jets. Faraday rotation measurements are another important tool for investigating the B fields of AGN jets. A helical B field component should result in a systematic gradient in the observed Faraday rotation across the jet. Real observed radio images have finite resolution; typical beam sizes for cm-wavelength VLBI observations are often comparable to or larger than the intrinsic jet widths, raising questions about how well resolved a jet must be in the transverse direction in order to reliably detect transverse Faraday-rotation structure. This thesis presents results of Monte Carlo simulations of Faraday rotation images designed to directly investigate this question, together with a detailed investigation into the probabilities of observing spurious Faraday Rotation gradients as a result of random noise and finite resolution. These simulations clearly demonstrate the possibility of detecting transverse Faraday-rotation structures even when the intrinsic jet widths are appreciably smaller than the beam width.
Resumo:
Huntington’s Disease (HD) is a rare autosomal dominant neurodegenerative disease caused by the expression of a mutant Huntingtin (muHTT) protein. Therefore, preventing the expression of muHTT by harnessing the specificity of the RNA interference (RNAi) pathway is a key research avenue for developing novel therapies for HD. However, the biggest caveat in the RNAi approach is the delivery of short interfering RNA (siRNAs) to neurons, which are notoriously difficult to transfect. Indeed, despite the great advances in the field of nanotechnology, there remains a great need to develop more effective and less toxic carriers for siRNA delivery to the Central Nervous System (CNS). Thus, the aim of this thesis was to investigate the utility of modified amphiphilic β-cyclodextrins (CDs), oligosaccharide-based molecules, as non-viral vectors for siRNA delivery for HD. Modified CDs were able to bind and complex siRNAs forming nanoparticles capable of delivering siRNAs to ST14A-HTT120Q cells and to human HD fibroblasts, and reducing the expression of the HTT gene in these in vitro models of HD. Moreover, direct administration of CD.siRNA nanoparticles into the R6/2 mouse brain resulted in significant HTT gene expression knockdown and selective alleviation of rotarod motor deficits in this mouse model of HD. In contrast to widely used transfection reagents, CD.siRNA nanoparticles only induced limited cytotoxic and neuroinflammatory responses in multiple brain-derived cell-lines, and also in vivo after single direct injections into the mouse brain. Alternatively, we have also described a PEGylation-based formulation approach to further stabilise CD.siRNA nanoparticles and progress towards a systemic delivery nanosystem. Resulting PEGylated CD.siRNA nanoparticles showed increased stability in physiological saltconditions and, to some extent, reduced protein-induced aggregation. Taken together, the work outlined in this thesis identifies modified CDs as effective, safe and versatile siRNA delivery systems that hold great potential for the treatment of CNS disorders, such as HD.
Resumo:
The conventional meaning of culture is ‘widely shared and strongly held values’ of a particular group or society (Bradley and Parker, 2006: 89). Culture is not a rigid concept; it can be influenced or altered by new ideas or forces. This research examines the ways in which one set of ideas in particular, that is, those associated with New Public Management, have impacted upon the administrative culture of 'street-level' bureaucrats and professionals within Irish social policy. Lipsky (1980: 3) defined 'street-level' bureaucrats as ‘public service workers who interact directly with citizens in the course of their jobs, and who have substantial discretion in the execution of their work’. Utilising the Competing Values Framework (CVF) in the analysis of eighty three semi-structured interviews with 'street-level' bureaucrats and professionals, an evaluation is made as to the impact of NPM ideas on both visible and invisible aspects of administrative culture. Overall, the influence of NPM is confined to superficial aspects of administrative culture such as; increased flexibility in working hours and to some degree job contracts; increased time commitment; and a customer service focus. However, the extent of these changes varies depending on policy sector and occupational group. Aspects of consensual and hierarchical cultures remain firmly in place. These coincide with features of developmental and market cultures. Contrary to the view that members of hierarchical and consensual culture would pose resistance to change, this research clearly illustrates that a very large appetite for change exists in the attitudes of 'street-level' bureaucrats and professionals within Irish social policy, with many of them suggesting changes that correspond to NPM ideas. This study demonstrates the relevance of employing the CVF model as it is clear that administrative culture is very much a dynamic system of competing and co-existing cultures.
Resumo:
Communication is important for social and other behavioural interactions in most marine mammal species. The bottlenose dolphin (Tursiops truncatus, Montagu, 1821) is a highly social species that use whistles as communication calls to express identity and to initiate and maintain contact between socially interactive individuals. In this thesis, the degree of variability in whistle behaviour and whistle characteristics was examined between different habitats on a range of spatial scales. The whistle characteristics that best discriminated between different communities were investigated, along with exploration of whistle variation in relation to habitat type, levels of social interaction and relatedness. Finally, the use and variability of individually distinctive calls (signature whistles) within and between Irish and US waters were also examined. Relatively high levels of whistle variation were found within a genetically and socially isolated population of dolphins in the Shannon Estuary, reflecting the need for individual identification and distinctive whistles in a population with long term site fidelity and high levels of social cohesion. Variation between reproductively separate communities in Irish waters was relatively small except between animals in inshore compared with continental shelf waters. The greatest differences in whistle structure overall were evident between dolphins using inshore and offshore US waters, likely reflecting social isolation of the two distinct ecotypes that occur in these waters but also variation in behaviour or habitat conditions. Variation found among inshore communities in US waters reflected similarities in habitat use and levels of social interaction. These findings suggest that vocal variation is socially mediated, behaviourally maintained and dependent on levels of social contact between individuals. The findings contribute to our understanding of the interaction of factors influencing vocalisation behaviour in this behaviourally complex and ecologically plastic species.
Resumo:
This thesis critically investigates the divergent international approaches to the legal regulation of the patentability of computer software inventions, with a view to identifying the reforms necessary for a certain, predictable and uniform inter-jurisdictional system of protection. Through a critical analysis of the traditional and contemporary US and European regulatory frameworks of protection for computer software inventions, this thesis demonstrates the confusion and legal uncertainty resulting from ill-defined patent laws and inconsistent patent practices as to the scope of the “patentable subject matter” requirement, further compounded by substantial flaws in the structural configuration of the decision-making procedures within which the patent systems operate. This damaging combination prevents the operation of an accessible and effective Intellectual Property (IP) legal framework of protection for computer software inventions, capable of securing adequate economic returns for inventors whilst preserving the necessary scope for innovation and competition in the field, to the ultimate benefit of society. In exploring the substantive and structural deficiencies in the European and US regulatory frameworks, this thesis develops to ultimately highlight that the best approach to the reform of the legal regulation of software patentability is two-tiered. It demonstrates that any reform to achieve international legal harmony first requires the legislature to individually clarify (Europe) or restate (US) the long-standing inadequate rules governing the scope of software “patentable subject matter”, together with the reorganisation of the unworkable structural configuration of the decision-making procedures. Informed by the critical analysis of the evolution of the “patentable subject matter” requirement for computer software in the US, this thesis particularly considers the potential of the reforms of the European patent system currently underway, to bring about certainty, predictability and uniformity in the legal treatment of computer software inventions.
Resumo:
Anaerobic digestion (AD) of biodegradable waste is an environmentally and economically sustainable solution which incorporates waste treatment and energy recovery. The organic fraction of municipal solid waste (OFMSW), which comprises mostly of food waste, is highly degradable under anaerobic conditions. Biogas produced from OFMSW, when upgraded to biomethane, is recognised as one of the most sustainable renewable biofuels and can also be one of the cheapest sources of biomethane if a gate fee is associated with the substrate. OFMSW is a complex and heterogeneous material which may have widely different characteristics depending on the source of origin and collection system used. The research presented in this thesis investigates the potential energy resource from a wide range of organic waste streams through field and laboratory research on real world samples. OFMSW samples collected from a range of sources generated methane yields ranging from 75 to 160 m3 per tonne. Higher methane yields are associated with source segregated food waste from commercial catering premises as opposed to domestic sources. The inclusion of garden waste reduces the specific methane yield from household organic waste. In continuous AD trials it was found that a conventional continuously stirred tank reactor (CSTR) gave the highest specific methane yields at a moderate organic loading rate of 2 kg volatile solids (VS) m-3 digester day-1 and a hydraulic retention time of 30 days. The average specific methane yield obtained at this loading rate in continuous digestion was 560 ± 29 L CH4 kg-1 VS which exceeded the biomethane potential test result by 5%. The low carbon to nitrogen ratio (C: N <14:1) associated with canteen food waste lead to increasing concentrations of volatile fatty acids in line with high concentrations of ammonia nitrogen at higher organic loading rates. At an organic loading rate of 4 kg VS m-3day-1 the specific methane yield dropped considerably (381 L CH4 kg-1 VS), the pH rose to 8.1 and free ammonia (NH3 ) concentrations reached toxicity levels towards the end of the trial (ca. 950 mg L-1). A novel two phase AD reactor configuration consisting of a series of sequentially fed leach bed reactors connected to an upflow anaerobic sludge blanket (UASB) demonstrated a high rate of organic matter decay but resulted in lower specific methane yields (384 L CH4 kg-1 VS) than the conventional CSTR system.
Resumo:
This study explores the experiences of stress and burnout in Irish second level teachers and examines the contribution of a number of individual, environmental and health factors in burnout development. As no such study has previously been carried out with this sample, a mixed-methods approach was adopted in order to comprehensively investigate the subject matter. Teaching has consistently been identified as a particularly stressful occupation and research investigating its development is of great importance in developing measures to address the problem. The first phase of study involved the use of focus groups conducted with a total of 20 second-level teachers from 11 different schools in the greater Cork city area. Findings suggest that teachers experience a variety of stressors – in class, in the staff room and outside of school. The second phase of study employed a survey to examine the factors associated with burnout. Analysis of 192 responses suggested that burnout results from a combination of demographic, personality, environmental and coping factors. Burnout was also found to be associated with a number of physical symptoms, particularly trouble sleeping and fatigue. Findings suggest that interventions designed to reduce burnout must reflect the complexity of the problem and its development. Based on the research findings, interventions that combine individual and organisational approaches should provide the optimal chance of effectively tackling burnout.
Resumo:
Structural Health Monitoring (SHM) is an integral part of infrastructure maintenance and management systems due to socio-economic, safety and security reasons. The behaviour of a structure under vibration depends on structure characteristics. The change of structure characteristics may suggest the change in system behaviour due to the presence of damage(s) within. Therefore the consistent, output signal guided, and system dependable markers would be convenient tool for the online monitoring, the maintenance, rehabilitation strategies, and optimized decision making policies as required by the engineers, owners, managers, and the users from both safety and serviceability aspects. SHM has a very significant advantage over traditional investigations where tangible and intangible costs of a very high degree are often incurred due to the disruption of service. Additionally, SHM through bridge-vehicle interaction opens up opportunities for continuous tracking of the condition of the structure. Research in this area is still in initial stage and is extremely promising. This PhD focuses on using bridge-vehicle interaction response for SHM of damaged or deteriorating bridges to monitor or assess them under operating conditions. In the present study, a number of damage detection markers have been investigated and proposed in order to identify the existence, location, and the extent of an open crack in the structure. The theoretical and experimental investigation has been conducted on Single Degree of Freedom linear system, simply supported beams. The novel Delay Vector Variance (DVV) methodology has been employed for characterization of structural behaviour by time-domain response analysis. Also, the analysis of responses of actual bridges using DVV method has been for the first time employed for this kind of investigation.
Resumo:
Initial studies have demonstrated that intra- renal infusion of Ang (1-7) caused a diuresis and natriuresis that was proportional to the degree of activation of the Renin Angiotensin Aldosterone System (RAAS). This raised the question as why the magnitude of this diuresis and natriuresis was compromised in rats receiving a high sodium diet (suppressed RAAS) and enhanced in low sodium fed rats (activated RAAS)? Could the answer lie with changes in intra-renal AT1 or Mas receptor expression? Interestingly, the observed Ang (1-7) induced increases in sodium and water excretion in rats receiving either a low or normal sodium diet were and blocked in the presence of the AT 1 receptor antagonist (Losartan) in the presence of the, 'Mas' receptor antagonist (A-779). These data suggest that both AT1 and 'Mas' receptors need to be functional in order to fully mediate the renal responses to intra-renal Ang (1-7) infusion. Importantly, further experimentation also revealed that there is a proportional relationship between AT 1 receptor expression in the rat renal cortex and the magnitude of the excretory actions of intra renal Ang (1-7) infusion, which is only partially dependent on the level of 'Mas' receptor expression. These observations suggest that although Ang (1-7) induced increases in sodium and water excretion are mediated by the Mas receptor, the magnitude of these excretory responses appear to be dependent upon the level of AT 1 receptor expression and more specifically Ang II/ AT 1 receptor signalling. Thus in rats receiving a low sodium diet, Ang (1-7) acts via the Mas receptor to inhibit Ang II/ AT 1 receptor signalling. In rats receiving a high sodium diet the down regulated AT 1 receptor expression implies a reduction in Ang II/ AT 1 receptor signalling which renders the counter-regulatory effects of intra-renal Ang (1-7) infusion redundant.
Resumo:
Chinese sports are developing under very complex and unique political, economic, and cultural circumstances in the global age. This study aims to investigate the process of globalization in basketball through an examination of its multidimensional manifestations. The study aligns itself with Ritzer’s (2003, 2007b) conceptualization of dichotomizing the process of globalization into grobalization and glocalization. On that basis, the trajectory of basketball globalization in China is identified as the result of a contextual and competing interplay between the penetration of the NBA and the consequent engagement of Chinese basketball. A qualitative methodological approach was conducted to achieve the research aim. Data were collected from a number of sources, including official documents and semi-structured interviews with relevant basketball participants. The study reveals that globalization and basketball in China, in the political and institutional dimension, is a conflicting process. The universalization of the NBA’s governance model could not be fully assimilated due to the centralization of power in the Chinese government, which is hindering the further professionalization and marketization of basketball. In the economic dimension, the globalization process is seen to interplay with the local basketball market, which is growing thanks to the adaption of the NBA’s marketing strategies. In the cultural dimension, the study demonstrates that the NBA has to some extent cosmopolitanized and consumerized Chinese basketball culture, while resistance from both the state and the Chinese people has risen, creolizing the globalization of basketball culture in China.
Resumo:
A proactive risk management strategy seeks to prevent accidents from taking place and maintain the safety of a system. In this context, the task of identifying and disseminating early warning signs and signals is among the most important. The problem is that warning signs that are present before an accident takes place are often being overlooked and not picked up or identified as warning signs. If these warning signs were responded to, then an accident may be averted. Accidents occuring in the critical domain of a drinking water treatments works can have serious implications for the public health of consumers of the water supplied. Realising and comprehending early warning signs is a major challenge for the domain of systems safety and especially in the domain of a water treatment works. The approaches that are typically used to enhance the realisation, comprehension and dissemination of early warning signs in the water treatment domain in Ireland mainly involves the creation of accident scenarios, the use of monitoring data and procedures for the dissemination of warnings. While all of these approaches are all useful to inform the mental or process models of possible accident scenarios, nevertheless, accidents are still occurring in this domain. Therefore, a new approach to enhance the comprehension of and effective dissemination of early warning signs is required in order to improve safety and proactive risk management strategies. The contributions of this thesis is the provision of a set of attributes associated with the early warning sign concept that provides meaningful data on the early warning signs and allows recipients to better comprehend them. The values of these attributes were customised for application in the water treatment domain. This research proves that early warning signs at a water treatment works received with information on their attributes are comprehended and communicated more effectively and efficiently than the usual pragmatic approach and thereby improves the safety and proactive risk management strategies.
Resumo:
The analysis of energy detector systems is a well studied topic in the literature: numerous models have been derived describing the behaviour of single and multiple antenna architectures operating in a variety of radio environments. However, in many cases of interest, these models are not in a closed form and so their evaluation requires the use of numerical methods. In general, these are computationally expensive, which can cause difficulties in certain scenarios, such as in the optimisation of device parameters on low cost hardware. The problem becomes acute in situations where the signal to noise ratio is small and reliable detection is to be ensured or where the number of samples of the received signal is large. Furthermore, due to the analytic complexity of the models, further insight into the behaviour of various system parameters of interest is not readily apparent. In this thesis, an approximation based approach is taken towards the analysis of such systems. By focusing on the situations where exact analyses become complicated, and making a small number of astute simplifications to the underlying mathematical models, it is possible to derive novel, accurate and compact descriptions of system behaviour. Approximations are derived for the analysis of energy detectors with single and multiple antennae operating on additive white Gaussian noise (AWGN) and independent and identically distributed Rayleigh, Nakagami-m and Rice channels; in the multiple antenna case, approximations are derived for systems with maximal ratio combiner (MRC), equal gain combiner (EGC) and square law combiner (SLC) diversity. In each case, error bounds are derived describing the maximum error resulting from the use of the approximations. In addition, it is demonstrated that the derived approximations require fewer computations of simple functions than any of the exact models available in the literature. Consequently, the regions of applicability of the approximations directly complement the regions of applicability of the available exact models. Further novel approximations for other system parameters of interest, such as sample complexity, minimum detectable signal to noise ratio and diversity gain, are also derived. In the course of the analysis, a novel theorem describing the convergence of the chi square, noncentral chi square and gamma distributions towards the normal distribution is derived. The theorem describes a tight upper bound on the error resulting from the application of the central limit theorem to random variables of the aforementioned distributions and gives a much better description of the resulting error than existing Berry-Esseen type bounds. A second novel theorem, providing an upper bound on the maximum error resulting from the use of the central limit theorem to approximate the noncentral chi square distribution where the noncentrality parameter is a multiple of the number of degrees of freedom, is also derived.