389 research outputs found

    Elliptic flow of electrons from heavy-flavor hadron decays in Au+Au collisions at sNN=\sqrt{s_{\rm NN}} = 200, 62.4, and 39 GeV

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    We present measurements of elliptic flow (v2v_2) of electrons from the decays of heavy-flavor hadrons (eHFe_{HF}) by the STAR experiment. For Au+Au collisions at sNN=\sqrt{s_{\rm NN}} = 200 GeV we report v2v_2, for transverse momentum (pTp_T) between 0.2 and 7 GeV/c using three methods: the event plane method (v2v_{2}{EP}), two-particle correlations (v2v_2{2}), and four-particle correlations (v2v_2{4}). For Au+Au collisions at sNN\sqrt{s_{\rm NN}} = 62.4 and 39 GeV we report v2v_2{2} for pT<2p_T< 2 GeV/c. v2v_2{2} and v2v_2{4} are non-zero at low and intermediate pTp_T at 200 GeV, and v2v_2{2} is consistent with zero at low pTp_T at other energies. The v2v_2{2} at the two lower beam energies is systematically lower than at sNN=\sqrt{s_{\rm NN}} = 200 GeV for pT<1p_T < 1 GeV/c. This difference may suggest that charm quarks interact less strongly with the surrounding nuclear matter at those two lower energies compared to sNN=200\sqrt{s_{\rm NN}} = 200 GeV.Comment: Version accepted by PR

    Suppression of AP1 Transcription Factor Function in Keratinocyte Suppresses Differentiation

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    Our previous study shows that inhibiting activator protein one (AP1) transcription factor function in murine epidermis, using dominant-negative c-jun (TAM67), increases cell proliferation and delays differentiation. To understand the mechanism of action, we compare TAM67 impact in mouse epidermis and in cultured normal human keratinocytes. We show that TAM67 localizes in the nucleus where it forms TAM67 homodimers that competitively interact with AP1 transcription factor DNA binding sites to reduce endogenous jun and fos factor binding. Involucrin is a marker of keratinocyte differentiation that is expressed in the suprabasal epidermis and this expression requires AP1 factor interaction at the AP1-5 site in the promoter. TAM67 interacts competitively at this site to reduce involucrin expression. TAM67 also reduces endogenous c-jun, junB and junD mRNA and protein level. Studies with c-jun promoter suggest that this is due to reduced transcription of the c-jun gene. We propose that TAM67 suppresses keratinocyte differentiation by interfering with endogenous AP1 factor binding to regulator elements in differentiation-associated target genes, and by reducing endogenous c-jun factor expression

    Targeted plant improvement through genome editing: from laboratory to field

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    This review illustrates how far we have come since the emergence of GE technologies and how they could be applied to obtain superior and sustainable crop production. The main challenges of today's agriculture are maintaining and raising productivity, reducing its negative impact on the environment, and adapting to climate change. Efficient plant breeding can generate elite varieties that will rapidly replace obsolete ones and address ongoing challenges in an efficient and sustainable manner. Site-specific genome editing in plants is a rapidly evolving field with tangible results. The technology is equipped with a powerful toolbox of molecular scissors to cut DNA at a pre-determined site with different efficiencies for designing an approach that best suits the objectives of each plant breeding strategy. Genome editing (GE) not only revolutionizes plant biology, but provides the means to solve challenges related to plant architecture, food security, nutrient content, adaptation to the environment, resistance to diseases and production of plant-based materials. This review illustrates how far we have come since the emergence of these technologies and how these technologies could be applied to obtain superior, safe and sustainable crop production. Synergies of genome editing with other technological platforms that are gaining significance in plants lead to an exciting new, post-genomic era for plant research and production. In previous months, we have seen what global changes might arise from one new virus, reminding us of what drastic effects such events could have on food production. This demonstrates how important science, technology, and tools are to meet the current time and the future. Plant GE can make a real difference to future sustainable food production to the benefit of both mankind and our environment.European Cooperation in Science and Technology (COST) CA18111info:eu-repo/semantics/publishedVersio

    Performance of the CMS Cathode Strip Chambers with Cosmic Rays

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    The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device in the CMS endcaps. Their performance has been evaluated using data taken during a cosmic ray run in fall 2008. Measured noise levels are low, with the number of noisy channels well below 1%. Coordinate resolution was measured for all types of chambers, and fall in the range 47 microns to 243 microns. The efficiencies for local charged track triggers, for hit and for segments reconstruction were measured, and are above 99%. The timing resolution per layer is approximately 5 ns

    J/\u3c8 production cross section and its dependence on charged-particle multiplicity in p\u202f+\u202fp collisions at s=200 GeV

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    We present a measurement of inclusive J/\u3c8 production at mid-rapidity ( |y|<1 ) in p+p collisions at a center-of-mass energy of s=200 GeV with the STAR experiment at the Relativistic Heavy Ion Collider (RHIC). The differential production cross section for J/\u3c8 as a function of transverse momentum ( pT ) for 0<pT<14 GeV/c and the total cross section are reported and compared to calculations from the color evaporation model and the non-relativistic Quantum Chromodynamics model. The dependence of J/\u3c8 relative yields in three pT intervals on charged-particle multiplicity at mid-rapidity is measured for the first time in p+p collisions at s=200 GeV and compared with that measured at s=7 TeV, PYTHIA8 and EPOS3 Monte Carlo generators, and the Percolation model prediction

    Improved measurement of the longitudinal spin transfer to \u39b and \u39b hyperons in polarized proton-proton collisions at s =200 GeV

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    The longitudinal spin transfer DLL to \u39b and \u39b\uaf hyperons produced in high-energy polarized proton--proton collisions is expected to be sensitive to the helicity distribution functions of strange quarks and anti-quarks of the proton, and to longitudinally polarized fragmentation functions. We report an improved measurement of DLL from data obtained at a center-of-mass energy of s 1a = 200 GeV with the STAR detector at RHIC. The data have an approximately twelve times larger figure-of-merit than prior results and cover |\u3b7|< 1.2 in pseudo-rapidity with transverse momenta pT up to 6 GeV/c. In the forward scattering hemisphere at largest pT, the longitudinal spin transfer is found to be DLL = -0.036 \ub1 0.048 (stat) \ub1 0.013(sys) for \u39b hyperons and DLL = 0.032 \ub1 0.043\,(stat) \ub1 0.013\,(sys) for \u39b\uaf anti-hyperons. The dependences on \u3b7 and pT are presented and compared with model evaluations
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