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We report STAR results on the azimuthal anisotropy parameter v2 for strange particles K0S, Lambda , and Lambda -bar at midrapidity in Au+Au collisions at sqrt[sNN]=130 GeV at the Relativistic Heavy Ion Collider. The value of v2 as a function of transverse momentum, pt, of the produced particle and collision centrality is presented for both particles up to pt~3.0 GeV/c. A strong pt dependence in v2 is observed up to 2.0 GeV/c. The v2 measurement is compared with hydrodynamic model calculations. The physics implications of the pt integrated v2 magnitude as a function of particle mass are also discussed.
Inclusive transverse momentum distributions of charged hadrons within 0.2<pT<6.0 GeV/c have been measured over a broad range of centrality for Au+Au collisions at sqrt[sNN]=130 GeV. Hadron yields are suppressed at high pT in central collisions relative to peripheral collisions and to a nucleon-nucleon reference scaled for collision geometry. Peripheral collisions are not suppressed relative to the nucleon-nucleon reference. The suppression varies continuously at intermediate centralities. The results indicate significant nuclear medium effects on high-pT hadron production in heavy-ion collisions at high energy.
We report the first measurement of strange ( Lambda ) and antistrange ( Lambda -bar) baryon production from sqrt[sNN]=130 GeV Au+Au collisions at the Relativistic Heavy Ion Collider (RHIC). Rapidity density and transverse mass distributions at midrapidity are presented as a function of centrality. The yield of Lambda and Lambda -bar hyperons is found to be approximately proportional to the number of negative hadrons. The production of Lambda -bar hyperons relative to negative hadrons increases very rapidly with transverse momentum. The magnitude of the increase cannot be described by existing hadronic string fragmentation models alone.
We present a systematic analysis of two-pion interferometry in Au+Au collisions at sqrt[sNN]=200GeV using the STAR detector at Relativistic Heavy Ion Collider. We extract the Hanbury-Brown and Twiss radii and study their multiplicity, transverse momentum, and azimuthal angle dependence. The Gaussianness of the correlation function is studied. Estimates of the geometrical and dynamical structure of the freeze-out source are extracted by fits with blast-wave parametrizations. The expansion of the source and its relation with the initial energy density distribution is studied.
Elliptic flow from nuclear collisions is a hadronic observable sensitive to the early stages of system evolution. We report first results on elliptic flow of charged particles at midrapidity in Au+Au collisions at sqrt[sNN] = 130 GeV using the STAR Time Projection Chamber at the Relativistic Heavy Ion Collider. The elliptic flow signal, v2, averaged over transverse momentum, reaches values of about 6% for relatively peripheral collisions and decreases for the more central collisions. This can be interpreted as the observation of a higher degree of thermalization than at lower collision energies. Pseudorapidity and transverse momentum dependence of elliptic flow are also presented.
Elliptic flow from nuclear collisions is a hadronic observable sensitive to the early stages of system evolution. We report first results on elliptic flow of charged particles at midrapidity in Au+Au collisions at sqrt(s_NN)=130 GeV using the STAR TPC at RHIC. The elliptic flow signal, v_2, averaged over transverse momentum, reaches values of about 6% for relatively peripheral collisions and decreases for the more central collisions. This can be interpreted as the observation of a higher degree of thermalization than at lower collision energies. Pseudorapidity and transverse momentum dependence of elliptic flow are also presented.
We present the first measurements of charge-dependent correlations on angular difference variables η1 − η2 (pseudorapidity) and φ1 − φ2 (azimuth) for primary charged hadrons with transverse momentum 0.15 <= pt <= 2 GeV/c and |η| <= 1.3 from Au–Au collisions at √sNN = 130 GeV. We observe correlation structures not predicted by theory but consistent with evolution of hadron emission geometry with increasing centrality from one-dimensional fragmentation of color strings along the beam direction to an at least two-dimensional hadronization geometry along the beam and azimuth directions of a hadron-opaque bulk medium.
Mid-rapidity transverse mass spectra and multiplicity densities of charged and neutral kaons are reported for Au + Au collisions at √sNN = 130 GeV at RHIC. The spectra are exponential in transverse mass, with an inverse slope of about 280 MeV in central collisions. The multiplicity densities for these particles scale with the negative hadron pseudo-rapidity density. The charged kaon to pion ratios are K+/π− = 0.161± 0.002(stat) ± 0.024(syst) and K−/π− = 0.146± 0.002(stat) ± 0.022(syst) for the most central collisions. The K+/π− ratio is lower than the same ratio observed at the SPS while the K−/π− is higher than the SPS result. The ratios are enhanced by about 50% relative to p + p and p¯ + p collision data at similar energies.
Men and women differ substantially regarding height, weight, and body fat. Interestingly, previous work detecting genetic effects for waist-to-hip ratio, to assess body fat distribution, has found that many of these showed sex-differences. However, systematic searches for sex-differences in genetic effects have not yet been conducted. Therefore, we undertook a genome-wide search for sexually dimorphic genetic effects for anthropometric traits including 133,723 individuals in a large meta-analysis and followed promising variants in further 137,052 individuals, including a total of 94 studies. We identified seven loci with significant sex-difference including four previously established (near GRB14/COBLL1, LYPLAL1/SLC30A10, VEGFA, ADAMTS9) and three novel anthropometric trait loci (near MAP3K1, HSD17B4, PPARG), all of which were significant in women, but not in men. Of interest is that sex-difference was only observed for waist phenotypes, but not for height or body-mass-index. We found no evidence for sex-differences with opposite effect direction for men and women. The PPARG locus is of specific interest due to its link to diabetes genetics and therapy. Our findings demonstrate the importance of investigating sex differences, which may lead to a better understanding of disease mechanisms with a potential relevance to treatment options.
While it is apparent that rare variation can play an important role in the genetic architecture of autism spectrum disorders (ASDs), the contribution of common variation to the risk of developing ASD is less clear. To produce a more comprehensive picture, we report Stage 2 of the Autism Genome Project genome-wide association study, adding 1301 ASD families and bringing the total to 2705 families analysed (Stages 1 and 2). In addition to evaluating the association of individual single nucleotide polymorphisms (SNPs), we also sought evidence that common variants, en masse, might affect the risk. Despite genotyping over a million SNPs covering the genome, no single SNP shows significant association with ASD or selected phenotypes at a genome-wide level. The SNP that achieves the smallest P-value from secondary analyses is rs1718101. It falls in CNTNAP2, a gene previously implicated in susceptibility for ASD. This SNP also shows modest association with age of word/phrase acquisition in ASD subjects, of interest because features of language development are also associated with other variation in CNTNAP2. In contrast, allele scores derived from the transmission of common alleles to Stage 1 cases significantly predict case status in the independent Stage 2 sample. Despite being significant, the variance explained by these allele scores was small (Vm< 1%). Based on results from individual SNPs and their en masse effect on risk, as inferred from the allele score results, it is reasonable to conclude that common variants affect the risk for ASD but their individual effects are modest.
Although autism spectrum disorders (ASDs) have a substantial genetic basis, most of the known genetic risk has been traced to rare variants, principally copy number variants (CNVs). To identify common risk variation, the Autism Genome Project (AGP) Consortium genotyped 1558 rigorously defined ASD families for 1 million single-nucleotide polymorphisms (SNPs) and analyzed these SNP genotypes for association with ASD. In one of four primary association analyses, the association signal for marker rs4141463, located within MACROD2, crossed the genome-wide association significance threshold of P < 5 × 10−8. When a smaller replication sample was analyzed, the risk allele at rs4141463 was again over-transmitted; yet, consistent with the winner's curse, its effect size in the replication sample was much smaller; and, for the combined samples, the association signal barely fell below the P < 5 × 10−8 threshold. Exploratory analyses of phenotypic subtypes yielded no significant associations after correction for multiple testing. They did, however, yield strong signals within several genes, KIAA0564, PLD5, POU6F2, ST8SIA2 and TAF1C.
North-western Africa has a large Andrena fauna, but parts of the country away from coastal areas remain poorly studied, and confusion persists as to the identity of certain taxa due to the long history of study combined with imperfectly examined type material. New fieldwork, genetic barcoding, and study of museum material has substantially improved our understanding of this region. Eleven new species are described: A. (Aciandrena) bendai sp. nov., A. (Aciandrena) ifranensis sp. nov., A. (Euandrena) berberica sp. nov., A. (Hoplandrena) darha sp. nov., A. (Micrandrena) anammas sp. nov., A. (Micrandrena) gemina sp. nov., A. (Micrandrena) tinctoria sp. nov., and A. (incertae sedis) muelleri sp. nov., all from Morocco, and A. (Aciandrena) quieta sp. nov., A. (Euandrena) abscondita sp. nov., and A. (Taeniandrena) prazi sp. nov. from Morocco and Tunisia. Andrena (Aciandrena) nitidilabris Pérez, 1895 was misdiagnosed, and is actually the senior synonym of A. (Graecandrena) montarca parva Warncke, 1974 syn. nov. Andrena (Aciandrena) pisantyi sp. nov. is described from Algeria, Tunisia, and Israel, conforming to A. nitidilabris auctorum sensu Warncke. Andrena (Graecandrena) andina Warncke, 1974 stat. nov. and A. (Micrandrena) heliaca Warncke, 1974 stat. nov. are elevated from sub species to species status. Lectotypes are designated for A. (Melanapis) ephippium Spinola, 1838,
A. (Melanapis) rutila Spinola, 1838, A. (Simandrena) rhypara Pérez, 1903, and A. (Suandrena) savignyi Spinola, 1838. Neotypes are designated for A. (Melandrena) soror Dours, 1872 and A. (Notandrena) nigroviridula Dours, 1873. The female of A. (Aciandrena) triangulivalvis Wood, 2020 is described. The following seven additional synonymies are reported (senior name first): A. (Chrysandrena) testaceipes Saunders, 1908 = A. (Chrysandrena) rubricorpora Wood, 2021 syn. nov., A. (incertae sedis) maidaqi Scheuchl & Gusenleitner, 2007 = A. (Carandrena) hoggara Wood, 2021 syn. nov., A. (Lepidandrena) tuberculifera Pérez, 1895 = A. (Poecilandrena) nigriclypeus Wood, 2020 syn. nov., A. (Notandrena) albohirta Saunders, 1908 = A. (Notandrena) eddaensis Gusenleitner, 1998 syn. nov., A. (Notandrena) microthorax Pérez, 1895 = A. (Notandrena) nigrocyanea Saunders, 1908 syn. nov., A. (Simandrena) rhypara = A. (Simandrena) palumba Warncke, 1974 syn. nov., and A. (Taeniandrena) poupillieri Dours, 1872 = A. (Taeniandrena) lecerfi Benoist, 1961 syn. nov. Andrena (Notandrena) viridiaenea Pérez, 1903 is returned to synonymy with A. nigroviridula. Relative to the 2020 baseline, 16 Andrena species are newly recorded for Morocco, and six species are removed from the faunal list. These revisions bring the total number of Andrena species known from Morocco to 202 with 25 endemic species, making it one of the hotspots for Andrena diversity globally.