5,182 research outputs found

    η\eta meson production of high-energy nuclear collisions at NLO

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    The transverse momentum spectrum of η\eta meson in relativistic heavy-ion collisions is studied at the next-to-leading-order (NLO) within the perturbative QCD, where the jet quenching effect in the QGP is incorporated with the effectively medium-modified η\eta fragmentation functions using the higher-twist approach. We show that the theoretical simulations could give nice descriptions of PHENIX data on η\eta meson in both p+p\rm p+p and central Au+Au\rm Au+Au collisions at the RHIC, and also provide numerical predictions of η\eta spectra in central Pb+Pb\rm Pb+Pb collisions with sNN=2.76\sqrt{s_{NN}}=2.76~TeV at the LHC. The ratios of η/π0\eta/\pi^0 in p+p\rm p+p and in central Au+Au\rm Au+Au collisions at 200200~GeV are found to overlap in a wide pTp_T region, which matches well the measured ratio η/π0\eta / \pi^0 by PHENIX. We demonstrate that, at the asymptotic region when pTp_{T} \rightarrow \infty the ratios of η/π0\eta/\pi^{0} in both Au+Au\rm Au+Au and p+p\rm p+p are almost determined only by quark jets fragmentation and thus approach to the one in e+ee^{+} e^{-} scattering; in addition, the almost identical gluon (quark) contribution fractions to η\eta and to π\pi result in a rather moderate variation of η/π0\eta/\pi^{0} distribution at intermediate and high pTp_T region in A+A\rm A+A relative to that in p+p\rm p+p; while a slightly higher η/π0\eta/\pi^{0} at small pTp_T in Au+Au\rm Au+Au can be observed due to larger suppression of gluon contribution fraction to π0\pi^{0} as compared to the one to η\eta. The theoretical prediction for η/π0\eta / \pi^0 at the LHC has also been presented.Comment: 7 pages, 8 figures, 2 typos corrected, revision for publicatio

    Nuclear suppression of ϕ\phi meson yields with large pTp_T at the RHIC and the LHC

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    We calculate ϕ\phi meson transverse momentum spectra in p+p collisions as well as their nuclear suppressions in central A+A collisions both at the RHIC and the LHC in LO and NLO with the QCD-improved parton model. We have included the parton energy loss effect in hot/dense QCD medium with the effectively medium-modified ϕ\phi fragmentation functions in the higher-twist approach of jet quenching. The nuclear modification factors of ϕ\phi meson in central Au+Au collisions at the RHIC and central Pb+Pb collisions at the LHC are provided, and a nice agreement of our numerical results at NLO with the ALICE measurement is observed. Predictions of yield ratios of neutral mesons such as ϕ/π0\phi/\pi^0, ϕ/η\phi/\eta and ϕ/ρ0\phi/\rho^0 at large pTp_T in relativistic heavy-ion collisions are also presented for the first time.Comment: 7 pages, 8 figure

    Genetic variants in ELOVL2 and HSD17B12 predict melanoma‐specific survival

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    Fatty acids play a key role in cellular bioenergetics, membrane biosynthesis and intracellular signaling processes and thus may be involved in cancer development and progression. In the present study, we comprehensively assessed associations of 14,522 common single‐nucleotide polymorphisms (SNPs) in 149 genes of the fatty‐acid synthesis pathway with cutaneous melanoma disease‐specific survival (CMSS). The dataset of 858 cutaneous melanoma (CM) patients from a published genome‐wide association study (GWAS) by The University of Texas M.D. Anderson Cancer Center was used as the discovery dataset, and the identified significant SNPs were validated by a dataset of 409 CM patients from another GWAS from the Nurses’ Health and Health Professionals Follow‐up Studies. We found 40 noteworthy SNPs to be associated with CMSS in both discovery and validation datasets after multiple comparison correction by the false positive report probability method, because more than 85% of the SNPs were imputed. By performing functional prediction, linkage disequilibrium analysis, and stepwise Cox regression selection, we identified two independent SNPs of ELOVL2 rs3734398 T>C and HSD17B12 rs11037684 A>G that predicted CMSS, with an allelic hazards ratio of 0.66 (95% confidence interval = 0.51–0.84 and p = 8.34 × 10−4) and 2.29 (1.55–3.39 and p = 3.61 × 10−5), respectively. Finally, the ELOVL2 rs3734398 variant CC genotype was found to be associated with a significantly increased mRNA expression level. These SNPs may be potential markers for CM prognosis, if validated by additional larger and mechanistic studies

    Meta contrastive label correction for financial time series

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    Financial applications such as stock price forecasting, usually face an issue that under the predefined labeling rules, it is hard to accurately predict the directions of stock movement. This is because traditional ways of labeling, taking Triple Barrier Method, for example, usually gives us inaccurate or even corrupted labels. To address this issue, we focus on two main goals. One is that our proposed method can automatically generate correct labels for noisy time series patterns, while at the same time, the method is capable of boosting classification performance on this new labeled dataset. Based on the aforementioned goals, our approach has the following three novelties: First, we fuse a new contrastive learning algorithm into the meta-learning framework to estimate correct labels iteratively when updating the classification model inside. Moreover, we utilize images generated from time series data through Gramian angular field and representative learning. Most important of all, we adopt multi-task learning to forecast temporal-variant labels. In the experiments, we work on 6% clean data and the rest unlabeled data. It is shown that our method is competitive and outperforms a lot compared with benchmarks

    First Principles Studies on 3-Dimentional Strong Topological Insulators: Bi2Te3, Bi2Se3 and Sb2Te3

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    Bi2Se3, Bi2Te3 and Sb2Te3 compounds are recently predicted to be 3-dimentional (3D) strong topological insulators. In this paper, based on ab-initio calculations, we study in detail the topological nature and the surface states of this family compounds. The penetration depth and the spin-resolved Fermi surfaces of the surface states will be analyzed. We will also present an procedure, from which highly accurate effective Hamiltonian can be constructed, based on projected atomic Wannier functions (which keep the symmetries of the systems). Such Hamiltonian can be used to study the semi-infinite systems or slab type supercells efficiently. Finally, we discuss the 3D topological phase transition in Sb2(Te1-xSex)3 alloy system.Comment: 8 pages,17 figure
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