239 research outputs found
Intelligent Noninvasive Diagnosis of Aneuploidy:Raw Values and Highly Imbalanced Dataset
The objective of this paper is to introduce a noninvasive diagnosis procedure for aneuploidy and to minimize the social and financial cost of prenatal diagnosis tests that are performed for fetal aneuploidies in an early stage of pregnancy. We propose a method by using artificial neural networks trained with data from singleton pregnancy cases, while undergoing first trimester screening. Three different datasets' with a total of 122 362 euploid and 967 aneuploid cases were used in this study. The data for each case contained markers collected from the mother and the fetus. This study, unlike previous studies published by the authors for a similar problem differs in three basic principles: 1) the training of the artificial neural networks is done by using the markers' values in their raw form (unprocessed), 2) a balanced training dataset is created and used by selecting only a representative number of euploids for the training phase, and 3) emphasis is given to the financials and suggest hierarchy and necessity of the available tests. The proposed artificial neural networks models were optimized in the sense of reaching a minimum false positive rate and at the same time securing a 100% detection rate for Trisomy 21. These systems correctly identify other aneuploidies (Trisomies 13&18, Turner, and Triploid syndromes) at a detection rate greater than 80%. In conclusion, we demonstrate that artificial neural network systems can contribute in providing noninvasive, effective early screening for fetal aneuploidies with results that compare favorably to other existing methods
First Trimester Noninvasive Prenatal Diagnosis:A Computational Intelligence Approach
The objective of this study is to examine the potential value of using machine learning techniques such as artificial neural network (ANN) schemes for the noninvasive estimation, at 11-13 weeks of gestation, the risk for euploidy, trisomy 21 (T21), and other chromosomal aneuploidies (O.C.A.), from suitable sonographic, biochemical markers, and other relevant data. A database(1) consisted of 51,208 singleton pregnancy cases, while undergoing first trimester screening for aneuploidies has been used for the building, training, and verification of the proposed method. From all the data collected for each case from the mother and the fetus, the following 9 are considered by the collaborating obstetricians as the most relevant to the problem in question: maternal age, previous pregnancy with T21, fetal crown-rump length, serum free beta-hCG in multiples of the median (MoM), pregnancy-associated plasma protein-A in MoM, nuchal translucency thickness, nasal bone, tricuspid flow, and ductus venosus flow. The dataset was randomly divided into a training set that was used to guide the development of various ANN schemes, support vector machines, and k-nearest neighbor models. An evaluation set used to determine the performance of the developed systems. The evaluation set, totally unknown to the proposed system, contained 16,898 cases of euploidy fetuses, 129 cases of T21, and 76 cases of O.C.A. The best results were obtained by the ANN system, which identified correctly all T21 cases, i.e., 0% false negative rate (FNR) and 96.1% of euploidies, i.e., 3.9% false positive rate (FPR), meaning that no child would have been born with T21 if only that 3.9% of all pregnancies had been sent for invasive testing. The aim of this work is to produce a practical tool for the obstetrician which will ideally provide 0% FNR and to recommend the minimum possible number of cases for further testing such as invasive. In conclusion, it was demonstrated that ANN schemes can provide an effective early screening for fetal aneuploidies at a low FPR with results that compare favorably to those of existing systems
Efficient Bayesian inference for COM-Poisson regression models
COM-Poisson regression is an increasingly popular model for count data. Its main advantage is that it permits to model separately the mean and the variance of the counts, thus allowing the same covariate to affect in different ways the average level and the variability of the response variable. A key limiting factor to the use of the COM-Poisson distribution is the calculation of the normalisation constant: its accurate evaluation can be time-consuming and is not always feasible. We circumvent this problem, in the context of estimating a Bayesian COM-Poisson regression, by resorting to the exchange algorithm, an MCMC method applicable to situations where the sampling model (likelihood) can only be computed up to a normalisation constant. The algorithm requires to draw from the sampling model, which in the case of the COM-Poisson distribution can be done efficiently using rejection sampling. We illustrate the method and the benefits of using a Bayesian COM-Poisson regression model, through a simulation and two real-world data sets with different levels of dispersion
Security (studies) and the limits of critique: why we should think through struggle
This paper addresses the political and epistemological stakes of knowledge production in post-structuralist Critical Security Studies. It opens a research agenda in which struggles against dominant regimes of power/knowledge are entry-points for analysis. Despite attempts to gain distance from the word ‘security’, through interrogation of wider practices and schemes of knowledge in which security practices are embedded, post-structuralist CSS too quickly reads security logics as determinative of modern/liberal forms of power and rule. At play is an unacknowledged ontological investment in ‘security’, structured by disciplinary commitments and policy discourse putatively critiqued. Through previous ethnographic research, we highlight how struggles over dispossession and oppression call the very frame of security into question, exposing violences inadmissible within that frame. Through the lens of security, the violence of wider strategies of containing and normalizing politics are rendered invisible, or a neutral backdrop against which security practices take place. Building on recent debates on critical security methods, we set out an agenda where struggle provokes an alternative mode of onto political investment in critical examination of power and order
Reclaiming the political : emancipation and critique in security studies
The critical security studies literature has been marked by a shared commitment towards the politicization of security – that is, the analysis of its assumptions, implications and the practices through which it is (re)produced. In recent years, however, politicization has been accompanied by a tendency to conceive security as connected with a logic of exclusion, totalization and even violence. This has resulted in an imbalanced politicization that weakens critique. Seeking to tackle this situation, the present article engages with contributions that have advanced emancipatory versions of security. Starting with, but going beyond, the so-called Aberystwyth School of security studies, the argument reconsiders the meaning of security as emancipation by making the case for a systematic engagement with the notions of reality and power. This revised version of security as emancipation strengthens critique by addressing political dimensions that have been underplayed in the critical security literature
The effect of shrinkage cracks on the load bearing capacity of steel-fibre-reinforced roller-compacted-concrete pavements
Editors' introduction: neoliberalism and/as terror
The articles in this special issue are drawn from papers presented at a conference entitled “Neoliberalism and/as Terror”, held at the Nottingham Conference Centre at Nottingham Trent University by the Critical Terrorism Studies BISA Working Group (CSTWG) on 15-16 September 2014. The conference was supported by both a BISA workshop grant and supplementary funds from Nottingham Trent University’s Politics and International Relations Department and the Critical Studies on Terrorism journal. Papers presented at the conference aimed to extend research into the diverse linkages between neoliberalism and terrorism, including but extending beyond the contextualisation of pre-emptive counterterrorism technologies and privatised securities within relevant economic and ideological contexts. Thus, the conference sought also to stimulate research into the ways that neoliberalism could itself be understood as terrorism, asking - amongst other questions - whether populations are themselves terrorised by neoliberal policy. The articles presented in this special issue reflect the conference aims in bringing together research on the neoliberalisation of counterterrorism and on the terror of neoliberalism
Like a thief in the night : Agamben, Hobbes and the messianic transvaluation of security
The article addresses the reinterpretation of the problematic of security in the messianic turn in contemporary continental political thought. I focus on Giorgio Agamben's reinterpretation of Hobbes's Leviathan in Stasis, which restores an eschatological dimension to this foundational text of modern security politics. Hobbes's commonwealth has been traditionally read as a secularized version of the katechon, a force that restrains the state of nature while drawing on its resources. Instead, Agamben argues that for Hobbes, the state is neither the analogue of God's kingdom on earth nor the katechon that delays its arrival, but the profane power that will disappear when the kingdom of God is established on earth. It is thus in principle incapable of attaining the peace and security that it claims to provide, perpetually producing insecurity and violence in the guise of protection. In Agamben's reading, it is precisely this failure of the state's security apparatuses that assists the advent of the messianic event in an oblique fashion. The exposure of this failure does not aspire to the improvement of the apparatuses of security or resign us to inescapable insecurity but only affirms the need to render the present apparatuses inoperative, bringing forth a future without them.Peer reviewe
Constructing resilience through security and surveillance: The politics, practices and tensions of security-driven resilience
This article illuminates how, since 9/11, security policy has gradually become more central to a range of resilience discourses and practices. As this process draws a wider range of security infrastructures, organizations and approaches into the enactment of resilience, security practices are enabled through more palatable and legitimizing discourses of resilience. This article charts the emergence and proliferation of security-driven resilience logics, deployed at different spatial scales, which exist in tension with each other. We exemplify such tensions in practice through a detailed case study from Birmingham, UK: ‘Project Champion’ an attempt to install over 200 high-resolution surveillance cameras, often invisibly, around neighbourhoods with a predominantly Muslim population. Here, practices of security-driven resilience came into conflict with other policy priorities focused upon community-centred social cohesion, posing a series of questions about social control, surveillance and the ability of national agencies to construct community resilience in local areas amidst state attempts to label the same spaces as ‘dangerous’. It is argued that security-driven logics of resilience generate conflicts in how resilience is operationalized, and produce and reproduce new hierarchical arrangements which, in turn, may work to subvert some of the founding aspirations and principles of resilience logic itself
Capturing protest in urban environments:The ‘police kettle’ as a territorial strategy
‘Kettling’ has emerged in recent decades as an established, if controversial, tactic of public order policing. Departing from a historical emphasis on dispersal, kettling instead acts to contain protesters within a police cordon for sustained periods of time. This article elaborates upon the spatial and temporal logics of kettling by investigating the conditions of is historical emergence. We argue that kettling should be understood as a territorial strategy that co-evolved in relation to forms of disruptive protest. Whereas techniques of crowd dispersal serve to diffuse a unified collective, ‘kettling’ aims to capture the volatile intensities of public dissent and exhaust its political energies. Drawing on police manuals, media coverage, accounts from activists and expert interviews, we show how the ‘kettle’ re-territorializes protest by acting on its spatio-temporal and affective constitution. By fabricating an inner outside of the urban milieu, freezing the time of collective mobilization and inducing debilitating affects such as fear and boredom, kettling intervenes into the scene of political subjectification that each congregation of protesting bodies seeks to fashion
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