On the Low Surface Magnetic Field Structure of Quark Stars

Following some of the recent articles on hole super-conductivity and related phenomena by Hirsch \cite{H1,H2,H3}, a simple model is proposed to explain the observed low surface magnetic field of the expected quark stars. It is argued that the diamagnetic moments of the electrons circulating in the electro-sphere induce a magnetic field, which forces the existing quark star magnetic flux density to become dilute. We have also analysed the instability of normal-superconducting interface due to excess accumulation of magnetic flux lines, assuming an extremely slow growth of superconducting phase through a first order bubble nucleation type transition.Comment: 24 pages REVTEX, one .eps figure, psfig.sty is include

Quark matter imprint on Gravitational Waves from oscillating stars

We discuss the possibility that the detection of gravitational waves emitted by compact stars may allow to constrain the MIT bag model of quark matter equation of state. Our results show that the combined knowledge of the frequency of the emitted gravitational wave and of the mass, or the radiation radius, of the source allows one to discriminate between strange stars and neutron stars and set stringent bounds on the bag constants.Comment: Eight pages, four figures. Revised version, to appear on General Relativity and Gravitatio

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

Sequences related to HLA-DRα chain on human chromosome 6: Restriction enzyme polymorphism detected with DCα chain probes.

Three sets of cosmid clones--containing the HLA-DR alpha chain gene and two additional related genes--were isolated from human genomic DNA libraries by using a cDNA probe for the HLA-DR alpha chain. Southern blot analysis using DNA from somatic cell hybrids indicated that all of the clones mapped to chromosome 6. Partial sequence analysis showed that the two additional related genes were highly homologous to each other, and to the HLA-DR alpha chain, in parts of the exon that encoded the alpha 2 domain but were more divergent in intron sequences. One of the genes corresponds to the HLA-DR-related DC series. DNA probes made from this gene revealed marked restriction enzyme polymorphism when hybridized to genomic DNA from HLA-DR typed homozygous cell lines. The patterns obtained from a number of homozygous and heterozygous cell lines correlated with the HLA-DR crossreactive serotypes and also indicated that there is a further sequence in the haploid human genome that is closely homologous with the DC alpha chain sequence. One family was studied and showed the expected HLA-DR-associated inheritance of restriction enzyme patterns. No polymorphism has yet been demonstrated in restriction enzyme fragments that include the other cloned sequence, which may correspond to the SB alpha chain gene or to a novel HLA-DR-related gene. These experiments indicate that there are at least three sequences in the human genome related, but not identical, to the HLA-DR alpha chain gene