2,969 research outputs found
A composite likelihood approach to predict the sex of the baby
Full text linkCouples with diseases associated with the sexual chromosomes, as well as families in countries where the desire for a male is extreme, are interested in influencing the sex of the baby. We propose an original composite likelihood approach to analyse the relation between sex of the newborn and timing of the intercourse which leads to conception. Although there exist numerous works on this relation, only few studies have been carried out on independent datasets to validate the existing theories. Since the sex of the newborn is only known in case of conception, the full likelihood of the data is not easily defined without strong assumptions. A composite likelihood is a pseudo likelihood defined as the product of likelihood functions relative to subsets of the data. In particular, we consider two such likelihoods, one modelling the day- specific probabilities of conception and the other modelling the sex of the newborn given a conception has occurred. The methodology is applied to a dataset from a European fecundability study. The results show no significant dependence of the sex of the newborn on the time of intercourse. The method developed may be applied to other situations when data are affected by selective sampling
Unbiased approximations of products of expectations
Full text linkWe consider the problem of approximating the product of n expectations with respect to a common probability distribution μ. Such products routinely arise in statistics as values of the likelihood in latent variable models. Motivated by pseudo-marginal Markov chain Monte Carlo schemes, we focus on unbiased estimators of such products. The standard approach is to sample N particles from μ and assign each particle to one of the expectations. This is wasteful and typically requires the number of particles to grow quadratically with the number of expectations. We propose an alternative estimator that approximates each expectation using most of the particles while preserving unbiasedness. We carefully study its properties, showing that in latent variable contexts the proposed estimator needs only O(n) particles to match the performance of the standard approach with O(n2) particles. We demonstrate the procedure on two latent variable examples from approximate Bayesian computation and single-cell gene expression analysis, observing computational gains of the order of the number of expectations, i.e. data points, n
DESpace: spatially variable gene detection via differential expression testing of spatial clusters
Full text linkMotivation: Spatially resolved transcriptomics (SRT) enables scientists to investigate spatial context of mRNA abundance, including identifying spatially variable genes (SVGs), i.e., genes whose expression varies across the tissue. Although several methods have been proposed for this task, native SVG tools cannot jointly model biological replicates, or identify the key areas of the tissue affected by spatial variability.
Results: Here, we introduce DESpace, a framework, based on an original application of existing methods, to discover SVGs. In particular, our approach inputs all types of SRT data, summarizes spatial information via spatial clusters, and identifies spatially variable genes by performing differential gene expression testing between clusters. Furthermore, our framework can identify (and test) the main cluster of the tissue affected by spatial variability; this allows scientists to investigate spatial expression changes in specific areas of interest. Additionally, DESpace enables joint modelling of multiple samples (i.e., biological replicates); compared to inference based on
individual samples, this approach increases statistical power, and targets SVGs with consistent spatial patterns across replicates. Overall, in our benchmarks, DESpace displays good true positive rates, controls for false positive and false discovery rates, and is computationally efficient.
Availability and implementation: DESpace is freely distributed as a Bioconductor R package
Rozpor ako východisko, láska ako smer u Simone Weilovej (Contradiction as base, Love as direction in writings of Simone Weil)
No full textArticle is explaining contradiction and love, Simone Weil‘s essential terms of hermeneutics of human Being. It introduces close relation of these terms with her understanding of God as well as with her overall concept of religion. Author also mentions Simone Weil‘s inspirations with philosophical and spiritual concepts of the East
“I beg you to tell me what has become of Djamila”: The Political Mobilization of Simone de Beauvoir’s Readers During the Boupacha Affair
No full textBy Sophia Millman This is a condensed version of a Masters thesis dedicated to the political mobilization of Simone de Beauvoir’s readers. The citations from the letters were translated from French by the author. *** On June 2, 1960, the French government ordered all copies of the daily Algiers edition of Le Monde seized and destroyed to suppress the publication of Simone de Beauvoir’s article “Pour Djamila Boupacha.” Beauvoir, a self-professed “woman of letters”, not “of action[1]”, and one ..
Integrated friction measurements in hip wear simulations: Short-term results
No full textHip joint wear simulators are used extensively to simulate the dynamic behaviour of the human hip joint and, through the wear rate, gain a concrete indicator about the overall wear performance of different coupled bearings. Present knowledge of the dynamic behaviour of important concurrent indicators, such as the coefficient of friction, could prove helpful for the continuing improvement in applied biomaterials.
A limited number of commercial or custom-made simulators have been designed specifically for friction studies but always separately from wear tests; thus, analysis of these two important parameters has remained unconnected.
As a result, a new friction sensor has been designed, built, and integrated in a commercial biaxial rocking motion hip simulator. The aim of this study is to verify the feasibility of an experimental set-up in which the dynamic measurement of the friction factor could effectively be implemented in a standard wear test without compromising its general accuracy and repeatability.
A short wear test was run with the new set-up for 1x10(6) cycles. In particular, three soft-bearings (metal-on-polyethylene, Phi=28 mm) were tested; during the whole test, axial load and frictional torque about the vertical loading axis were synchronously recorded in order to calculate the friction factor. Additional analyses were performed on the specimens, before and after the test, in order to verify the accuracy of the wear test.
The average friction factor was 0.110 +/- 0.025. The friction sensors showed good accuracy and repeatability throughout. This innovative set-up was able to reproduce stable and reliable measurements. The results obtained encourage further investigations of this set-up for long-term assessment and using different combinations of materials
A comparative study of form and theology in the works of Flannery O'Connor and Simone Weil
Full text linkIn this comparative study of the form and theology of Flannery O'Connor and Simone Weil I interrogate how Weil's philosophical writings and her theology illuminate O'Connor's use of both narrative and non-fictional forms, and her Catholicism. The Introduction analyses how Weil's concept of superposed reading provides a new method of approaching both O'Connor, her writings, and O'Connor
studies, and focuses on how such apparently different women interconnect. Chapter One explores how both Weil and O'Connor attempt to write their theologies on the
souls of their readers yet are each subject to constraints imposed by form. Weil's concept of locating equilibrium between incommensurates is discussed, and her
distinctively philosophical approach to fictions and fictionality is used to investigate O'Connor's notion of prophetic fictions and the writer's role. Chapter Two assesses how both writers revivify Christian paradoxes. Weil's monstrous concept of affiiction, and O'Connor's use of the grotesque genre to jolt secular man into an
awareness of the sacred are scrutinised. Chapter Three studies how both writers consider an encounter between God and man is possible through the action of grace. My Conclusion interrogates how Weil's work can deepen our understanding of O'Connor's writings, and examines how successful O'Connor is at realising a truly
Christian literature. I conclude that despite being a writer of powerful fictions, O'Connor can not be totally successful in her mission as writer-prophet because
ultimately fiction escapes orthodoxy
Apomixis and genetic background affect distinct traits in Hieracium pilosella L. grown under competition
Full text linkISSN:1741-700
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