124 research outputs found
A Gravitational Aharonov-Bohm Effect, and its Connection to Parametric Oscillators and Gravitational Radiation
A thought experiment is proposed to demonstrate the existence of a
gravitational, vector Aharonov-Bohm effect. A connection is made between the
gravitational, vector Aharonov-Bohm effect and the principle of local gauge
invariance for nonrelativistic quantum matter interacting with weak
gravitational fields. The compensating vector fields that are necessitated by
this local gauge principle are shown to be incorporated by the DeWitt minimal
coupling rule. The nonrelativistic Hamiltonian for weak, time-independent
fields interacting with quantum matter is then extended to time-dependent
fields, and applied to problem of the interaction of radiation with
macroscopically coherent quantum systems, including the problem of
gravitational radiation interacting with superconductors. But first we examine
the interaction of EM radiation with superconductors in a parametric oscillator
consisting of a superconducting wire placed at the center of a high Q
superconducting cavity driven by pump microwaves. We find that the threshold
for parametric oscillation for EM microwave generation is much lower for the
separated configuration than the unseparated one, which then leads to an
observable dynamical Casimir effect. We speculate that a separated parametric
oscillator for generating coherent GR microwaves could also be built.Comment: 25 pages, 5 figures, YA80 conference (Chapman University, 2012
Optimizing real time fMRI neurofeedback for therapeutic discovery and development
While reducing the burden of brain disorders remains a top priority of organizations like the World Health Organization and National Institutes of Health, the development of novel, safe and effective treatments for brain disorders has been slow. In this paper, we describe the state of the science for an emerging technology, real time functional magnetic resonance imaging (rtfMRI) neurofeedback, in clinical neurotherapeutics. We review the scientific potential of rtfMRI and outline research strategies to optimize the development and application of rtfMRI neurofeedback as a next generation therapeutic tool. We propose that rtfMRI can be used to address a broad range of clinical problems by improving our understanding of brain–behavior relationships in order to develop more specific and effective interventions for individuals with brain disorders. We focus on the use of rtfMRI neurofeedback as a clinical neurotherapeutic tool to drive plasticity in brain function, cognition, and behavior. Our overall goal is for rtfMRI to advance personalized assessment and intervention approaches to enhance resilience and reduce morbidity by correcting maladaptive patterns of brain function in those with brain disorders
Preliminary dragonfly (Odonata) species list from the Pampa biome in Rio Grande do Sul, Brazil, with ecological notes for 19 new records for the State
List of Odonates from the Floresta Nacional de São Francisco de Paula (FLONA - SFP), with two new distribution records for Rio Grande do Sul, Brazil
Formation, evolution and multiplicity of brown dwarfs and giant exoplanets
This proceeding summarises the talk of the awardee of the Spanish
Astronomical Society award to the the best Spanish thesis in Astronomy and
Astrophysics in the two-year period 2006-2007. The thesis required a tremendous
observational effort and covered many different topics related to brown dwarfs
and exoplanets, such as the study of the mass function in the substellar domain
of the young sigma Orionis cluster down to a few Jupiter masses, the relation
between the cluster stellar and substellar populations, the accretion discs in
cluster brown dwarfs, the frequency of very low-mass companions to nearby young
stars at intermediate and wide separations, or the detectability of Earth-like
planets in habitable zones around ultracool (L- and T-type) dwarfs in the solar
neighbourhood.Comment: "Highlights of Spanish Astrophysics V", Proceedings of the VIII
Scientific Meeting of the Spanish Astronomical Society (SEA) held in
Santander, 7-11 July, 2008. Edited by J. Gorgas, L. J. Goicoechea, J. I.
Gonzalez-Serrano, J. M. Diego. Invited oral contribution to plenary sessio
An integrated map of structural variation in 2,504 human genomes
Structural variants are implicated in numerous diseases and make up the majority of varying nucleotides among human genomes. Here we describe an integrated set of eight structural variant classes comprising both balanced and unbalanced variants, which we constructed using short-read DNA sequencing data and statistically phased onto haplotype blocks in 26 human populations. Analysing this set, we identify numerous gene-intersecting structural variants exhibiting population stratification and describe naturally occurring homozygous gene knockouts that suggest the dispensability of a variety of human genes. We demonstrate that structural variants are enriched on haplotypes identified by genome-wide association studies and exhibit enrichment for expression quantitative trait loci. Additionally, we uncover appreciable levels of structural variant complexity at different scales, including genic loci subject to clusters of repeated rearrangement and complex structural variants with multiple breakpoints likely to have formed through individual mutational events. Our catalogue will enhance future studies into structural variant demography, functional impact and disease association. © 2015 Macmillan Publishers Limited. All rights reserved
Effects of Oxides on Tensile and Charpy Impact Properties and Fracture Toughness in Heat Affected Zones of Oxide-Containing API X80 Linepipe Steels
Integrating sequence and array data to create an improved 1000 Genomes Project haplotype reference panel
A major use of the 1000 Genomes Project (1000GP) data is genotype imputation in genome-wide association studies (GWAS). Here we develop a method to estimate haplotypes from low-coverage sequencing data that can take advantage of single-nucleotide polymorphism (SNP) microarray genotypes on the same samples. First the SNP array data are phased to build a backbone (or 'scaffold') of haplotypes across each chromosome. We then phase the sequence data 'onto' this haplotype scaffold. This approach can take advantage of relatedness between sequenced and non-sequenced samples to improve accuracy. We use this method to create a new 1000GP haplotype reference set for use by the human genetic community. Using a set of validation genotypes at SNP and bi-allelic indels we show that these haplotypes have lower genotype discordance and improved imputation performance into downstream GWAS samples, especially at low-frequency variants. © 2014 Macmillan Publishers Limited. All rights reserved
A draft human pangenome reference
Here the Human Pangenome Reference Consortium presents a first draft of the human pangenome reference. The pangenome contains 47 phased, diploid assemblies from a cohort of genetically diverse individuals. These assemblies cover more than 99% of the expected sequence in each genome and are more than 99% accurate at the structural and base pair levels. Based on alignments of the assemblies, we generate a draft pangenome that captures known variants and haplotypes and reveals new alleles at structurally complex loci. We also add 119 million base pairs of euchromatic polymorphic sequences and 1,115 gene duplications relative to the existing reference GRCh38. Roughly 90 million of the additional base pairs are derived from structural variation. Using our draft pangenome to analyse short-read data reduced small variant discovery errors by 34% and increased the number of structural variants detected per haplotype by 104% compared with GRCh38-based workflows, which enabled the typing of the vast majority of structural variant alleles per sample
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