17,588 research outputs found

    Modelling uncertainties for measurements of the H → γγ Channel with the ATLAS Detector at the LHC

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    The Higgs boson to diphoton (H → γγ) branching ratio is only 0.227 %, but this final state has yielded some of the most precise measurements of the particle. As measurements of the Higgs boson become increasingly precise, greater import is placed on the factors that constitute the uncertainty. Reducing the effects of these uncertainties requires an understanding of their causes. The research presented in this thesis aims to illuminate how uncertainties on simulation modelling are determined and proffers novel techniques in deriving them. The upgrade of the FastCaloSim tool is described, used for simulating events in the ATLAS calorimeter at a rate far exceeding the nominal detector simulation, Geant4. The integration of a method that allows the toolbox to emulate the accordion geometry of the liquid argon calorimeters is detailed. This tool allows for the production of larger samples while using significantly fewer computing resources. A measurement of the total Higgs boson production cross-section multiplied by the diphoton branching ratio (σ × Bγγ) is presented, where this value was determined to be (σ × Bγγ)obs = 127 ± 7 (stat.) ± 7 (syst.) fb, within agreement with the Standard Model prediction. The signal and background shape modelling is described, and the contribution of the background modelling uncertainty to the total uncertainty ranges from 18–2.4 %, depending on the Higgs boson production mechanism. A method for estimating the number of events in a Monte Carlo background sample required to model the shape is detailed. It was found that the size of the nominal γγ background events sample required a multiplicative increase by a factor of 3.60 to adequately model the background with a confidence level of 68 %, or a factor of 7.20 for a confidence level of 95 %. Based on this estimate, 0.5 billion additional simulated events were produced, substantially reducing the background modelling uncertainty. A technique is detailed for emulating the effects of Monte Carlo event generator differences using multivariate reweighting. The technique is used to estimate the event generator uncertainty on the signal modelling of tHqb events, improving the reliability of estimating the tHqb production cross-section. Then this multivariate reweighting technique is used to estimate the generator modelling uncertainties on background V γγ samples for the first time. The estimated uncertainties were found to be covered by the currently assumed background modelling uncertainty

    Responsible E-Waste Value Chains in Africa

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    Population growth, increasing prosperity and changing consumer habits globally are increasing demand for consumer electronics. Further to this, rapid changes in technology, falling prices, increased affordability and consumer appetite for new products have exacerbated e-waste management challenges and seen millions of tons of electronic devices become obsolete. This rapid literature review collates evidence from academic, policy focussed and grey literature on e-waste value chains. The report should be read I conjunction with an earlier report on e-waste management. E-waste is any electrical or electronic equipment, including all components, subassemblies and consumables, which are part of the equipment at the time the equipment becomes waste. When e-waste is collected and treated formally, it normally includes the following steps: Collection, Sorting and disassembly, Size reduction, Separation. The following five pillars of a sustainable e-waste management system have been identified: • Business and finance • Policy and regulation • Technology and skills • Monitoring and control • Marketing and awareness As such, to support the development of a responsible e-waste value chain, the following elements must be addressed. • Understanding how e-waste is currently managed • There is no one-size-fits all solution to building a robust e-waste management system based on extended producer responsibility. • An e-waste system built without a participatory approach is likely to be hampered by a series of issues. • An overarching policy is necessary • The choices made for the sector should be founded on two crucial elements – data from on the ground, and inputs from stakeholders. • Enforcement is incumbent on the government mandate The push towards a circular economy has provided stakeholders across the value chain with an impetus to initiate systemic improvements and invest in infrastructure and awareness raising.FCDO (Foreign, Commonwealth and Development Office

    Sponsorship image and value creation in E-sports

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    .E-sports games can drive the sports industry forward and sponsorship is the best way to engage consumers of this new sport. The purpose of this study is to examine the effect of sponsorship image and consumer participation in co-creation consumption activities on fans’ sponsorship response (represented by the variables interest, purchase intention and word of mouth) in e-sports. Four antecedent variables build sponsorship image (i.e., ubiquity of sport, sincerity of sponsor, attitude to sponsor and team identification). A quantitative approach is used for the purposes of this study. Some 445 questionnaires were filled in by fans who watch e-sports in Spain; these are analyzed using partial least squares structural equation modeling (PLS-SEM). The outcomes show that sponsor antecedents are crucial factors if a sponsor wants to change their sponsorship image and influence sponsorship response, and that it is also possible to use participation to improve responsesS

    Image classification over unknown and anomalous domains

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    A longstanding goal in computer vision research is to develop methods that are simultaneously applicable to a broad range of prediction problems. In contrast to this, models often perform best when they are specialized to some task or data type. This thesis investigates the challenges of learning models that generalize well over multiple unknown or anomalous modes and domains in data, and presents new solutions for learning robustly in this setting. Initial investigations focus on normalization for distributions that contain multiple sources (e.g. images in different styles like cartoons or photos). Experiments demonstrate the extent to which existing modules, batch normalization in particular, struggle with such heterogeneous data, and a new solution is proposed that can better handle data from multiple visual modes, using differing sample statistics for each. While ideas to counter the overspecialization of models have been formulated in sub-disciplines of transfer learning, e.g. multi-domain and multi-task learning, these usually rely on the existence of meta information, such as task or domain labels. Relaxing this assumption gives rise to a new transfer learning setting, called latent domain learning in this thesis, in which training and inference are carried out over data from multiple visual domains, without domain-level annotations. Customized solutions are required for this, as the performance of standard models degrades: a new data augmentation technique that interpolates between latent domains in an unsupervised way is presented, alongside a dedicated module that sparsely accounts for hidden domains in data, without requiring domain labels to do so. In addition, the thesis studies the problem of classifying previously unseen or anomalous modes in data, a fundamental problem in one-class learning, and anomaly detection in particular. While recent ideas have been focused on developing self-supervised solutions for the one-class setting, in this thesis new methods based on transfer learning are formulated. Extensive experimental evidence demonstrates that a transfer-based perspective benefits new problems that have recently been proposed in anomaly detection literature, in particular challenging semantic detection tasks

    Development and evaluation of a treatment package for men with an intellectual disability who sexually offend

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    Sex offending in the general population has been a focus of interest for some time due to the damaging nature of the behaviour, and the need to reduce recidivism. Theoretical and clinical advances (Finke1hor, 1986; HM Prison Service, 1996; Marshall, Anderson, & Fernandez, 1999; Serran & Marshall, 2010) in treatment for sex offenders in the general population have been extended to men with an intellectual disability at risk of sexual offending (Lindsay, 2009). The purpose of this project is to develop and evaluate the SOTSEC-ID version cftrus model. Participants are adult males from 15 different locations across England and Wales, with an intellectual disability or borderline cognitive functioning and who have committed sexual offences. A pilot study clarified assessments and procedures, and individual data over several years is presented. A qualitative study using Interpretive Phenomenological Analysis (JP A) illustrates the 'meaning making' of participants' treatment experience through six major themes. A reliability and validity study assesses the four main quantitative measures, QACSO, SAKA, SOSAS, and VESA, finding limited support for criterion validity for the SOSAS and SAKA, excellent inter-rater reli"ability for all four main measures, and good to excellent inter-rater reliability on all but the SAKA Finally, a quantitative study, in collaboration with the wider SOTSEC-ID group, uses a repeated measures design to compare the QACSO, SOSAS and SAKA across pre-group, post-group and follow. up. Significant main effects and post-hoc comparisons were in the predicted direction for all measures. A range of information on demographic, clinical and criminogenic factors including offending during treatment or follow-up are also presented. A recidivism rate of 12.3% over a year was calculated for the sample. The treatment model and collaborative framework is recommended for wider adoption

    Political Islam and grassroots activism in Turkey : a study of the pro-Islamist Virtue Party's grassroots activists and their affects on the electoral outcomes

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    This thesis presents an analysis of the spectacular rise of political Islam in Turkey. It has two aims: first to understand the underlying causes of the rise of the Welfare Party which -later became the Virtue Party- throughout the 1990s, and second to analyse how grassroots activism influenced this process. The thesis reviews the previous literature on the Islamic fundamentalist movements, political parties, political party systems and concentrates on the local party organisations and their effects on the party's electoral performance. It questions the categorisation of Islamic fundamentalism as an appropriate label for this movement. An exploration of such movements is particularly important in light of the event of 11`x' September. After exploring existing theoretical and case studies into political Islam and party activism, I present my qualitative case study. I have used ethnographic methodology and done participatory observations among grassroots activists in Ankara's two sub-districts covering 105 neighbourhoods. I examined the Turkish party system and the reasons for its collapse. It was observed that as a result of party fragmentation, electoral volatility and organisational decline and decline in the party identification among the citizens the Turkish party system has declined. However, the WP/VP profited from this trend enormously and emerged as the main beneficiary of this process. Empirical data is analysed in four chapters, dealing with the different aspects of the Virtue Party's local organisations and grassroots activists. They deal with change and continuity in the party, the patterns of participation, the routes and motives for becoming a party activist, the profile of party activists and the local party organisations. I explore what they do and how they do it. The analysis reveals that the categorisation of Islamic fundamentalism is misplaced and the rise of political Islam in Turkey cannot be explained as religious revivalism or the rise of Islamic fundamentalism. It is a political force that drives its strength from the urban poor which has been harshly affected by the IMF directed neoliberal economy policies. In conclusion, it is shown that the WP/VP's electoral chances were significantly improved by its very efficient and effective party organisations and highly committed grassroots activists

    Unraveling the effect of sex on human genetic architecture

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    Sex is arguably the most important differentiating characteristic in most mammalian species, separating populations into different groups, with varying behaviors, morphologies, and physiologies based on their complement of sex chromosomes, amongst other factors. In humans, despite males and females sharing nearly identical genomes, there are differences between the sexes in complex traits and in the risk of a wide array of diseases. Sex provides the genome with a distinct hormonal milieu, differential gene expression, and environmental pressures arising from gender societal roles. This thus poses the possibility of observing gene by sex (GxS) interactions between the sexes that may contribute to some of the phenotypic differences observed. In recent years, there has been growing evidence of GxS, with common genetic variation presenting different effects on males and females. These studies have however been limited in regards to the number of traits studied and/or statistical power. Understanding sex differences in genetic architecture is of great importance as this could lead to improved understanding of potential differences in underlying biological pathways and disease etiology between the sexes and in turn help inform personalised treatments and precision medicine. In this thesis we provide insights into both the scope and mechanism of GxS across the genome of circa 450,000 individuals of European ancestry and 530 complex traits in the UK Biobank. We found small yet widespread differences in genetic architecture across traits through the calculation of sex-specific heritability, genetic correlations, and sex-stratified genome-wide association studies (GWAS). We further investigated whether sex-agnostic (non-stratified) efforts could potentially be missing information of interest, including sex-specific trait-relevant loci and increased phenotype prediction accuracies. Finally, we studied the potential functional role of sex differences in genetic architecture through sex biased expression quantitative trait loci (eQTL) and gene-level analyses. Overall, this study marks a broad examination of the genetics of sex differences. Our findings parallel previous reports, suggesting the presence of sexual genetic heterogeneity across complex traits of generally modest magnitude. Furthermore, our results suggest the need to consider sex-stratified analyses in future studies in order to shed light into possible sex-specific molecular mechanisms

    How to Be a God

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    When it comes to questions concerning the nature of Reality, Philosophers and Theologians have the answers. Philosophers have the answers that can’t be proven right. Theologians have the answers that can’t be proven wrong. Today’s designers of Massively-Multiplayer Online Role-Playing Games create realities for a living. They can’t spend centuries mulling over the issues: they have to face them head-on. Their practical experiences can indicate which theoretical proposals actually work in practice. That’s today’s designers. Tomorrow’s will have a whole new set of questions to answer. The designers of virtual worlds are the literal gods of those realities. Suppose Artificial Intelligence comes through and allows us to create non-player characters as smart as us. What are our responsibilities as gods? How should we, as gods, conduct ourselves? How should we be gods
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