Pulsars as Fantastic Objects and Probes

Pulsars are fantastic objects, which show the extreme states of matters and plasma physics not understood yet. Pulsars can be used as probes for the detection of interstellar medium and even the gravitational waves. Here I review the basic facts of pulsars which should attract students to choose pulsar studies as their future projects.Comment: Invited Lecture on the "First Kodai-Trieste Workshop on Plasma Astrophysics", Kodaikanal Obs, India. Aug.27-Sept.7th, 2007. In: "Turbulence, Dynamos, Accretion Disks, Pulsars and Collective Plasma Processes". Get a copy from: http://www.springerlink.com/content/978-1-4020-8867-

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

Dual-polarised cavity-backed annular slot antenna of compact structure

A unidirectional dual-polarised antenna is presented, by applying a cavity-backed annular slot and two mutually perpendicular microstrip feed lines. To improve the isolation between two ports of the designed antenna, a pair of conductor strips is introduced at the opposite side of the feed lines and a metal cylinder into the cavity centre. Aimed at 2.4 GHz wireless local area network systems, a prototype antenna has been fabricated based on the FR4 substrate. The measured results show that an isolation value of over 33 dB can be attained and the co-polarised level is 30 dB larger than the cross-polarised in the main radiation direction. In addition to compact structure, the operating band with about 5 dBi antenna gain indicates the proposed antenna is suitable for indoor multiple-input-multiple-output (MIMO) base station systems

A method for self-radiation of Josephson junction arrays

We proposed a novel approach to self-radiation of Josephson junction arrays. Bicrystal Josephson junction arrays fabricated on a bicrystal substrate were integrated with a half-wavelength dipole array and embedded in a Fabry-Perot resonator. Considered as a dielectric resonator, the substrate could be stimulated to resonate in an appropriate mode at the same frequency as the Fabry-Perot resonator, which realized a coupling between Josephson junctions as well as a coupling between the junctions and microwave structures by means of a resonant interaction between junctions and resonators. Both simulations and experiments were performed. A YBCO bicrystal Josephson junction array with 166 junctions was measured at liquid nitrogen temperature. The maximal self-radiation power of 10 pW was detected at 75.2 GHz, which was in agreement with the simulation results

Clay mineral distribution in surface sediments of the northeastern South China Sea and surrounding fluvial drainage basins : source and transport.

International audienceClay mineralogy of surface samples throughout the northeastern South China Sea (SCS) and surrounding fluvial drainage basins has been investigated to reveal source and transport of detrital fine-grained sediments. Three characteristic end-members in clay mineral compositions were observed from three major provenances, respectively: major kaolinite and moderate illite and chlorite from the Pearl River, predominant illite and chlorite from Taiwan, and principal smectite from the Luzon arc system. The transport of four clay mineral species in the northeastern SCS is influenced by various mechanisms. Smectite derived from the Luzon arc system is transported mainly by surface current with significant influence of the Kuroshio intrusion, illite and chlorite from Taiwan are mainly carried by deep water current, while kaolinite from the Pearl River is affected obviously by the westward Guangdong Coastal Current and longshore current. A westerly tongue-shaped distribution of high contents of illite and chlorite mainly from Taiwan on the eastern shelf may result from the westward Guangdong Coastal Current during the winter. The results suggest that clay mineral assemblages in the northeastern SCS are mainly controlled by provenance supply and current transport and their downcore records do not bear contemporaneous paleoclimatic features. The implication of clay minerals for proxies of the late Quaternary East Asian monsoon evolution is realized through both the provenance supply and current transport processes. (C) 2010 Elsevier B.V. All rights reserved

Polycomb-Repressed Genes Have Permissive Enhancers that Initiate Reprogramming

Key regulatory genes, suppressed by Polycomb and H3K27me3, become active during normal differentiation and induced reprogramming. Using the well-characterized enhancer/promoter pair of MYOD1 as a model, we have identified a critical role for enhancers in reprogramming. We observed an unexpected nucleosome-depleted region (NDR) at the H3K4me1-enriched enhancer at which transcriptional regulators initially bind, leading to subsequent changes in the chromatin at the cognate promoter. Exogenous Myod1 activates its own transcription by binding first at the enhancer, leading to an NDR and transcription-permissive chromatin at the associated MYOD1 promoter. Exogenous OCT4 also binds first to the permissive MYOD1 enhancer but has a different effect on the cognate promoter, where the monovalent H3K27me3 marks are converted to the bivalent state characteristic of stem cells. Genome-wide, a high percentage of Polycomb targets are associated with putative enhancers in permissive states, suggesting that they may provide a widespread avenue for the initiation of cell-fate reprogramming