49,509 research outputs found
Identifying and responding to people with mild learning disabilities in the probation service
It has long been recognised that, like many other individuals, people with learningdisabilities find their way into the criminal justice system. This fact is not disputed. Whathas been disputed, however, is the extent to which those with learning disabilities arerepresented within the various agencies of the criminal justice system and the ways inwhich the criminal justice system (and society) should address this. Recently, social andlegislative confusion over the best way to deal with offenders with learning disabilities andmental health problems has meant that the waters have become even more muddied.Despite current government uncertainty concerning the best way to support offenders withlearning disabilities, the probation service is likely to continue to play a key role in thesupervision of such offenders. The three studies contained herein aim to clarify the extentto which those with learning disabilities are represented in the probation service, toexamine the effectiveness of probation for them and to explore some of the ways in whichprobation could be adapted to fit their needs.Study 1 and study 2 showed that around 10% of offenders on probation in Kent appearedto have an IQ below 75, putting them in the bottom 5% of the general population. Study 3was designed to assess some of the support needs of those with learning disabilities in theprobation service, finding that many of the materials used by the probation service arelikely to be too complex for those with learning disabilities to use effectively. To addressthis, a model for service provision is tentatively suggested. This is based on the findings ofthe three studies and a pragmatic assessment of what the probation service is likely to becapable of achieving in the near future
Modelling uncertainties for measurements of the H → γγ Channel with the ATLAS Detector at the LHC
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
RELATIONSHIP BETWEEN BODY-SEAT INTERFACE PRESSURE AND DISCOMFORT DURING ROWING
Discomfort and pressure-related tissue injury to the buttocks are common complaints among rowers. The soft tissues of the buttocks are non-uniformly loaded during rowing. The current state of literature on seating discomfort is inconclusive as to a desirable body-seat interface pressure pattern. The purpose of this study was to determine whether localising pressure under bony protuberances or diffusing pressure over soft tissues would result in the least amount of discomfort. Force sensing arrays were used to measure body-seat interface pressures in 11 elite female rowers during rowing. Peak pressure measures were identified and pressure gradients were calculated. Discomfort was quantified using a questionnaire, and pressure data were then correlated with discomfort scores.Discomfort was weakly correlated with each of maximal pressure gradient (r=0.45) and peak pressure (r=0.43). The findings indicate pressure should be redistributed in order to avoid concentrating pressure under the bony protuberances o f the buttocks
Unraveling the effect of sex on human genetic architecture
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
Optimizing the lateral beamforming step for filtered-delay multiply and sum beamforming to improve active contour segmentation using ultrafast ultrasound imaging
As an alternative to delay-and-sum beamforming, a novel beamforming technique called filtered-delay multiply and sum (FDMAS) was introduced recently to improve ultrasound B-mode image quality. Although a considerable amount of work has been performed to evaluate FDMAS performance, no study has yet focused on the beamforming step size, , in the lateral direction. Accordingly, the performance of FDMAS was evaluated in this study by fine-tuning to find its optimal value and improve boundary definition when balloon snake active contour (BSAC) segmentation was applied to a B-mode image in ultrafast imaging. To demonstrate the effect of altering in the lateral direction on FDMAS, measurements were performed on point targets, a tissue-mimicking phantom and in vivo carotid artery, by using the ultrasound array research platform II equipped with one 128-element linear array transducer, which was excited by 2-cycle sinusoidal signals. With 9-angle compounding, results showed that the lateral resolution (LR) of the point target was improved by 67.9% and 81.2%, when measured at −6 dB and −20 dB respectively, when was reduced from to . Meanwhile the image contrast ratio (CR) measured on the CIRS phantom was improved by 10.38 dB at the same reduction and the same number of compounding angles. The enhanced FDMAS results with lower side lobes and less clutter noise in the anechoic regions provides a means to improve boundary definition on a B-mode image when BSAC segmentation is applied
Recent Hong Kong cinema and the generic role of film noir in relation to the politics of identity and difference
This thesis identifies a connection in Hong Kong cinema with classical Hollywood film noir and examines what it will call a 'reinvestment' in film noir in recent films. It will show that this reinvestment is a discursive strategy that both engages the spectator-subject in the cinematic practice and disengages him or her from the hegemony of the discourse by decentring the narrative. The thesis argues that a cinematic practice has occurred in the recent reinvestment of film noir in Hong Kong, which restages the intertextual relay of the historical genre that gives rise to an expectation of ideas about social instability. The noir vision that is seen as related to the fixed categories of film narratives, characterizations and visual styles is reassessed in the course of the thesis using Derridian theory. The focus of analysis is the way in which the constitution of meanings is dependent on generic characteristics that are different. Key to the phenomenon is a film strategy that destabilizes, differs and defers the interpretation of crises-personal, social, political and/or cultural-by soliciting self-conscious re-reading of suffering, evil, fate, chance and fortune. It will be argued that such a strategy evokes the genre expectation as the film invokes a network of ideas regarding a world perceived by the audience in association with the noirish moods of claustrophobia, paranoia, despair and nihilism. The noir vision is thus mutated and transformed when the film device differs and defers the conception of the crises as tragic in nature by exposing the workings of the genre amalgamation and the ideological function of the cinematic discourse. Thus, noirishness becomes both an affect and an agent that contrives a self-reflexive re-reading of the tragic vision and of the conventional comprehension of reality within the discursive practice. The film strategy, as an agent that problematizes the film form and narrative, gives rise to what I call a politics of difference, which may also be understood as the Lyotardian 'language game' or a practice of 'pastiche' in Jameson's terminology. Under the influence of the film strategy, the spectator is enabled to negotiate his or her understanding of recent Hong Kong cinema diegetically and extra-diegetically by traversing different positions of cinematic identification. When the practice of genre amalgamation adopts the visual impact of the noirish film form, the film turns itself into a playing field of 'fatal' misrecognition or a site of question. Through cinematic identification and alienation from the identification, the spectator-subject is enabled to experience the misrecognition as the film slowly foregrounds the way in which the viewer's presence is implicated in the narrative. This thesis demonstrates that certain contemporary Hong Kong films introduce this selfconscious mode of explication and interpretation, which solicits the spectator to negotiate his or her subject-position in the course of viewing. The notions of identity and subjectivity under scrutiny will thus be reread. With reference to The Private Eye Blue, Swordsman II, City a/Glass and Happy Together, the thesis shall explore the ways in which the Hong Kong films enable and facilitate a negotiation of cultural identity
Anytime algorithms for ROBDD symmetry detection and approximation
Reduced Ordered Binary Decision Diagrams (ROBDDs) provide a dense and memory efficient representation of Boolean functions. When ROBDDs are applied in logic synthesis, the problem arises of detecting both classical and generalised symmetries. State-of-the-art in symmetry detection is represented by Mishchenko's algorithm. Mishchenko showed how to detect symmetries in ROBDDs without the need for checking equivalence of all co-factor pairs. This work resulted in a practical algorithm for detecting all classical symmetries in an ROBDD in O(|G|³) set operations where |G| is the number of nodes in the ROBDD. Mishchenko and his colleagues subsequently extended the algorithm to find generalised symmetries. The extended algorithm retains the same asymptotic complexity for each type of generalised symmetry. Both the classical and generalised symmetry detection algorithms are monolithic in the sense that they only return a meaningful answer when they are left to run to completion. In this thesis we present efficient anytime algorithms for detecting both classical and generalised symmetries, that output pairs of symmetric variables until a prescribed time bound is exceeded. These anytime algorithms are complete in that given sufficient time they are guaranteed to find all symmetric pairs. Theoretically these algorithms reside in O(n³+n|G|+|G|³) and O(n³+n²|G|+|G|³) respectively, where n is the number of variables, so that in practice the advantage of anytime generality is not gained at the expense of efficiency. In fact, the anytime approach requires only very modest data structure support and offers unique opportunities for optimisation so the resulting algorithms are very efficient. The thesis continues by considering another class of anytime algorithms for ROBDDs that is motivated by the dearth of work on approximating ROBDDs. The need for approximation arises because many ROBDD operations result in an ROBDD whose size is quadratic in the size of the inputs. Furthermore, if ROBDDs are used in abstract interpretation, the running time of the analysis is related not only to the complexity of the individual ROBDD operations but also the number of operations applied. The number of operations is, in turn, constrained by the number of times a Boolean function can be weakened before stability is achieved. This thesis proposes a widening that can be used to both constrain the size of an ROBDD and also ensure that the number of times that it is weakened is bounded by some given constant. The widening can be used to either systematically approximate an ROBDD from above (i.e. derive a weaker function) or below (i.e. infer a stronger function). The thesis also considers how randomised techniques may be deployed to improve the speed of computing an approximation by avoiding potentially expensive ROBDD manipulation
Epistemologies of possibility: social movements, knowledge production and political transformation
Urgent global problems - whether military conflicts, economic insecurities, immigration controls or mass incarceration-not only call for new modes of political action but also demand new forms of knowledge. For if knowledge frameworks both shape the horizons of social intelligibility and chart t he realms of political possibility, then epistemological interventions constitute a crucial part of social change. Social movements play a key role in this work by engaging in dissident knowledge practices that open up space for political transformation. But what are the processes and conditions through which social movements generate new ways of knowing?'What is politically at stake in the various knowledge strategies that activists use to generate social change? Despite a growing literature on the role of epistemological dimensions of protest, social movement studies tend to neglect specific questions of epistemological change. Often treating knowledge as a resource or object rather than a power relation and a social practice, social movement scholars tend to focus on content rather than production, frames rather than practices, taxonomies rather than processes. Missing is a more dynamic account of the conditions, means and power relations through which transformative knowledge practices come to be constituted and deployed. Seeking to better understand processes of epistemological transformation, this thesis explores the relationship between social movements, knowledge production and political change. Starting from an assumption that knowledge not only represents the world, but also works to constitute it, this thesis examines the role of social movement knowledge practices in shaping the conditions of political possibility. Drawing from the context of grassroots queer, transgender and feminist organizing around issues of prisons and border controls in North America, the project explores how activists generate new forms of knowledge and forge new spaces of political possibility. Working through a series of concepts-transformation, resistance, experience, co-optation, solidarity and analogy - this thesis explores different ways of understanding processes of epistemological change with in social movement contexts. It considers processes that facilitate or enable epistemological change and those that limit or prohibit such change. Bringing together a range of theoretical perspectives, including feminist, queer, critical race and post-structuralist analyses, and drawing on interviews with grassroots activists, the thesis explores what is politically at stake in the different ways we conceptualise, imagine and engage in processes of epistemological change
Intermittent Faking of Personality Profiles in High-Stakes Assessments: A Grade of Membership Analysis
In high stakes assessments of personality and similar attributes, test takers may engage in impression management (aka faking). This paper proposes to consider responses of every test taker as a potential mixture of ‘real’ (or retrieved) answers to questions, and ‘ideal’ answers intended to create a desired impression, with each type of response characterized by its own distribution and factor structure. Depending on the particular mix of response types in the test taker profile, grades of membership in the ‘real’ and ‘ideal’ profiles are defined. This approach overcomes the limitation of existing psychometric models that assume faking behavior to be consistent across test items. To estimate the proposed Faking-as-Grade-of-Membership (F-GoM) model, two-level factor mixture analysis is used, with two latent classes at the response (within) level, allowing grade of membership in ‘real’ and ‘ideal’ profiles, each underpinned by its own factor structure, at the person (between) level. For collected data, units of analysis can be item or scale scores, with the latter enabling analysis of questionnaires with many measured scales. The performance of the F-GoM model is evaluated in a simulation study, and compared against existing methods for statistical control of faking in an empirical application using archival recruitment data, which supported the validity of latent factors and classes assumed by the model using multiple control variables. The proposed approach is particularly useful for high-stakes assessment data and can be implemented with standard software packages
Studies on the insecticidal mechanism of Bacillus thuringiensis Vip3A and Cry proteins
El control de plagas y patógenos ha tenido un efecto importante en la mejora del rendimiento de los sistemas agrÃcolas a nivel mundial. Diferentes tipos de insecticidas quÃmicos se han usado extensivamente durante mucho tiempo para el control de plagas de insectos. Debido a la aparición de resistencias, problemas de contaminación de aguas y problemas de salud humana causados por dichos insecticidas de sÃntesis, la agricultura moderna necesita una estrategia de gestión integrada de plagas más saludable, respetuosa con el medio ambiente y sostenible. El uso de Bacillus thuringiensis (Bt) y sus proteÃnas insecticidas para el control de plagas es una de las estrategias biotecnológicas más importantes hasta la fecha. Además, los genes que codifican sus proteÃnas insecticidas han sido transferidos a plantas, las cuales están siendo utilizadas comercialmente, desde 1996 en gran parte del mundo para el control eficiente de numerosas plagas de insectos. En los últimos años, una nueva subclase de proteÃnas insecticidas secretables (Vip3) producida durante el crecimiento vegetativo de Bt se ha considerado para la aplicación combinada con las convencionalmente empleadas proteÃnas Cry, cuya aplicación se ve amenazada por la aparición de poblaciones de insectos resistentes. Las proteÃnas Vip3 no tienen homologÃa de secuencia con las proteÃnas Cry y son tóxicas para insectos lepidópteros, sin embargo, su modo de acción todavÃa no se conoce completamente. En este proyecto de tesis, con el objetivo de mejorar su aplicación en el control biotecnológico de plagas y la comprensión del modo de acción de las proteÃnas Vip3, se estudiaron diversos aspectos de su actividad insecticida (espectro de acción, resistencia cruzada e interacción con otras proteÃnas), y se realizó un estudio de los residuos clave para el mantenimiento de la estructura tridimensional y la toxicidad de la proteÃna Vip3Af mediante mutagénesis dirigida. También analizamos la posible implicación de la unión a receptores en la aparición de resistencia utilizando una cepa resistente que habÃa sido seleccionada con Vip3Aa. En primer lugar, se investigó la toxicidad de 10 toxinas Bt (Cry1Ab, Cry1Ac, Cry1Ah, Cry1Fa, Cry2Aa, Cry2b, Cry1Ie, Vip3Aa19, Vip3Aa16 y Vip3Ca) frente a Mythimna separata (plaga agrÃcola muy destructiva en Asia y Australia), asà como su aplicación combinada mediante bioensayos llevados a cabo en laboratorio. Los resultados mostraron que la concentración letal media LC50 (Cry1Ac/Vip3Aa19/Vip3Ca 3061 veces) se obtuvo rápidamente después de 8 o 9 generaciones de selección en laboratorio. Sin embargo, no se obtuvo resistencia notable seleccionando con Cry1Ab o Cry1F en la misma población y durante el mismo número de generaciones. En un estudio realizado por otros investigadores, también se encontró una respuesta rápida similar a la selección de Vip3Aa en H. virescens, alcanzando un nivel de resistencia > 2300 veces mayor en la décima generación. Es importante hacer notar que esta rápida evolución de la selección en condiciones de laboratorio contrasta con los resultados obtenidos con las proteÃnas Cry1, tanto en nuestro trabajo como por otros autores: una la población de O. furnacalis adquirió un nivel de resistencia a Cry1Ab de alrededor de 100 veces sólo después de 35 generaciones de selección; de manera similar, una población de O. nubilalis desarrolló una resistencia de más de 3000 veces a Cry1F después de 35 generaciones de selección. Esta diferencia en respuesta a la selección, además de reflejar una frecuencia mucho mayor de alelos de resistencia para Vip3Aa, puede sugerir diferencias en los mecanismos de resistencia a las proteÃnas Vip3Aa y Cry1, lo cual queda en evidencia cuando se estudia la unión de Vip3A a BBMV de insectos resistentes El análisis de la unión de 125I-Vip3Aa a BBMV de larvas de M. separata tanto de insectos susceptibles y resistentes no reveló ninguna diferencia de unión, ya sea cualitativa o cuantitativa. Los resultados sugieren que la unión alterada a los receptores de la membrana del intestino medio no es el principal mecanismo de resistencia a la proteÃna Vip3Aa. Numerosos estudios han demostrado que la alteración de los receptores de membrana es un mecanismo evolutivo común que confiere altos niveles de resistencia a las proteÃnas Cry, pero nunca se ha establecido su relación con la resistencia a Vip3A. Las diferencias de unión cualitativas o c
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