1,433 research outputs found
Evaluating aggregate effects of rare and common variants in the 1000 Genomes Project exon sequencing data using latent variable structural equation modeling
Methods that can evaluate aggregate effects of rare and common variants are limited. Therefore, we applied a two-stage approach to evaluate aggregate gene effects in the 1000 Genomes Project data, which contain 24,487 single-nucleotide polymorphisms (SNPs) in 697 unrelated individuals from 7 populations. In stage 1, we identified potentially interesting genes (PIGs) as those having at least one SNP meeting Bonferroni correction using univariate, multiple regression models. In stage 2, we evaluate aggregate PIG effects on trait, Q1, by modeling each gene as a latent construct, which is defined by multiple common and rare variants, using the multivariate statistical framework of structural equation modeling (SEM). In stage 1, we found that PIGs varied markedly between a randomly selected replicate (replicate 137) and 100 other replicates, with the exception of FLT1. In stage 1, collapsing rare variants decreased false positives but increased false negatives. In stage 2, we developed a good-fitting SEM model that included all nine genes simulated to affect Q1 (FLT1, KDR, ARNT, ELAV4, FLT4, HIF1A, HIF3A, VEGFA, VEGFC) and found that FLT1 had the largest effect on Q1 (Ī²std = 0.33 Ā± 0.05). Using replicate 137 estimates as population values, we found that the mean relative bias in the parameters (loadings, paths, residuals) and their standard errors across 100 replicates was on average, less than 5%. Our latent variable SEM approach provides a viable framework for modeling aggregate effects of rare and common variants in multiple genes, but more elegant methods are needed in stage 1 to minimize type I and type II error
Heralded single-photon generation using imperfect single-photon sources and a two-photon-absorbing medium
We propose a setup for a heralded, i.e. announced generation of a pure
single-photon state given two imperfect sources whose outputs are represented
by mixtures of the single-photon Fock state with the vacuum
. Our purification scheme uses beam splitters, photodetection and a
two-photon-absorbing medium. The admixture of the vacuum is fully eliminated.
We discuss two potential realizations of the scheme.Comment: 22 pages, 8 figures (LaTeX). In version v2 we have slightly modified
our setup so as to increase the success probability of single-photon
generation by a factor of two. In addition, in an appendix we discuss
alternative realizations of single-photon generation without a Mach-Zehnder
interferometer. Three new figures have been added. Version v3 is a revised
version published in Phys. Rev. A. It contains numerous minor corrections and
clarifications. A new figure has been added in order to clarify our
convention regarding labelling the field modes. The action of the beam
splitters in the Schroedinger picture is introduced. A new reference has been
include
Modeling the Pinning of Au and Ni Clusters on Graphite
The pinning of size-selected AuN and NiN clusters on graphite, for N=7ā100, is investigated by means of molecular dynamics simulations and the results are compared to experiment and previous work with Ag clusters. Ab initio calculations of the binding of the metal adatom and dimers on a graphite surface are used to parametrize the potentials used in the simulations. The clusters are projected normally towards a graphite surface and the value of the energy at which pinning first occurs, EP, is determined. Pinning is shown to occur when a surface defect, made by the cluster interaction, is first produced. The simulations give a good agreement with the experimentally determined pinning energy thresholds and the heights of the clusters on the surface. The gold clusters are shown to be flatter and more spread out than the nickel clusters which are more compact
Covenant Marriage Turns Five Years Old
Part I of this article discusses public policy rationales behind covenant marriage legislation, describes relevant aspects of Louisiana\u27s legislation, and summarizes the efforts of other states to enact covenant marriage legislation. Part II discusses methods of data collection and analysis and identifies the demographic characteristics of covenant married couples as opposed to standard married couples in Louisiana. Part III addresses the dynamics behind couples\u27 choice to have a covenant versus standard marriage. Part IV is an analysis of couples\u27 satisfaction with their marriage option and the gendered dynamics of different levels of satisfaction with the marital choice
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The U.S. Support Program to IAEA Safeguards - How It Works
The U.S. Support Program to International Atomic Energy Agency (IAEA) Safeguards (USSP) was established in 1977 to transfer US technology and expertise to assist the IAEA Department of Safeguards because its limited budget and scope would not allow for R&D activities and the procurement of specialized or customized equipment. Over the years, the USSP and the Department of Safeguards have worked together continuously to develop and improve processes for requesting, selecting, and managing projects that support the Safeguards verification mission. This paper will discuss the main USSP processes for accepting and processing Safeguards requests, and managing and reporting task progress
Covenant Marriage Turns Five Years Old
Part I of this article discusses public policy rationales behind covenant marriage legislation, describes relevant aspects of Louisiana\u27s legislation, and summarizes the efforts of other states to enact covenant marriage legislation. Part II discusses methods of data collection and analysis and identifies the demographic characteristics of covenant married couples as opposed to standard married couples in Louisiana. Part III addresses the dynamics behind couples\u27 choice to have a covenant versus standard marriage. Part IV is an analysis of couples\u27 satisfaction with their marriage option and the gendered dynamics of different levels of satisfaction with the marital choice
Why alternative teenagers self-harm: exploring the link between non-suicidal self-injury, attempted suicide and adolescent identity
Background:
The term āself-harmā encompasses both attempted suicide and non-suicidal self-injury (NSSI). Specific adolescent subpopulations such as ethnic or sexual minorities, and more controversially, those who identify as āAlternativeā (Goth, Emo) have been proposed as being more likely to self-harm, while other groups such as āJocksā are linked with protective coping behaviours (for example exercise). NSSI has autonomic (it reduces negative emotions) and social (it communicates distress or facilitates group ābondingā) functions. This study explores the links between such aspects of self-harm, primarily NSSI, and youth subculture.<p></p>
Methods:
An anonymous survey was carried out of 452 15 year old German school students. Measures included: identification with different youth cultures, i.e. Alternative (Goth, Emo, Punk), Nerd (academic) or Jock (athletic); social background, e.g. socioeconomic status; and experience of victimisation. Self-harm (suicide and NSSI) was assessed using Self-harm Behavior Questionnaire and the Functional Assessment of Self-Mutilation (FASM).<p></p>
Results:
An āAlternativeā identity was directly (rāāā0.3) and a āJockā identity inversely (rāāā-0.1) correlated with self-harm. āAlternativeā teenagers self-injured more frequently (NSSI 45.5% vs. 18.8%), repeatedly self-injured, and were 4ā8 times more likely to attempt suicide (even after adjusting for social background) than their non-Alternative peers. They were also more likely to self-injure for autonomic, communicative and social reasons than other adolescents.<p></p>
Conclusions:
About half of āAlternativeā adolescentsā self-injure, primarily to regulate emotions and communicate distress. However, a minority self-injure to reinforce their group identity, i.e. āTo feel more a part of a groupā
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