101
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The role of magnetoelastic strain on orbital control and transport properties in an LaTiO(3)-CoFe(2)O(4) heterostructure. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2009; 21:276002. [PMID: 21828504 DOI: 10.1088/0953-8984/21/27/276002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Epitaxial heterostructures of CoFe(2)O(4)/LaTiO(3)/LaAlO(3) have been successfully prepared by using the pulsed laser deposition technique. The magnetoresistance (MR) of the samples is negative and linear with field at H≥2 T, exhibiting no dependence on field directions. Nevertheless, when H<2 T, the MR is negative in a field parallel to the sample plane, but positive in that along the film normal. This novel observed anisotropic MR is explained in terms of the magnetic anisotropy in the ferrimagnetic layer, as well as the magnetoelastic coupling between the two. In fields of different directions, the top CoFe(2)O(4) layer contracts or expands in the sample plane due to the significant magnetostriction effect, changing its resistance accordingly and exerting compressive or tensile strains on the bottom LaTiO(3) layer. Apparently the orbital status and the one-electron bandwidth in the LaTiO(3) layer are altered, which leads to a change in resistance.
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102
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Observation of two-source interference in the photoproduction reaction AuAu --> AuAurho0. PHYSICAL REVIEW LETTERS 2009; 102:112301. [PMID: 19392193 DOI: 10.1103/physrevlett.102.112301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2008] [Indexed: 05/27/2023]
Abstract
In ultraperipheral relativistic heavy-ion collisions, a photon from the electromagnetic field of one nucleus can fluctuate to a quark-antiquark pair and scatter from the other nucleus, emerging as a rho{0}. The rho{0} production occurs in two well-separated (median impact parameters of 20 and 40 F for the cases considered here) nuclei, so the system forms a two-source interferometer. At low transverse momenta, the two amplitudes interfere destructively, suppressing rho{0} production. Since the rho{0} decays before the production amplitudes from the two sources can overlap, the two-pion system can only be described with an entangled nonlocal wave function, and is thus an example of the Einstein-Podolsky-Rosen paradox. We observe this suppression in 200 GeV per nucleon-pair gold-gold collisions. The interference is 87%+/-5%(stat.)+/-8%(syst.) of the expected level. This translates into a limit on decoherence due to wave function collapse or other factors of 23% at the 90% confidence level.
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103
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Indications of conical emission of charged hadrons at the BNL relativistic heavy ion collider. PHYSICAL REVIEW LETTERS 2009; 102:052302. [PMID: 19257508 DOI: 10.1103/physrevlett.102.052302] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2008] [Indexed: 05/27/2023]
Abstract
Three-particle azimuthal correlation measurements with a high transverse momentum trigger particle are reported for pp, d+Au, and Au+Au collisions at sqrt[s_{NN}]=200 GeV by the STAR experiment. Dijet structures are observed in pp, d+Au and peripheral Au+Au collisions. An additional structure is observed in central Au+Au data, signaling conical emission of correlated charged hadrons. The conical emission angle is found to be theta=1.37+/-0.02(stat)-0.07+0.06(syst), independent of p_{ perpendicular}.
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104
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System-size independence of directed flow measured at the BNL relativistic heavy-ion collider. PHYSICAL REVIEW LETTERS 2008; 101:252301. [PMID: 19113699 DOI: 10.1103/physrevlett.101.252301] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2008] [Indexed: 05/27/2023]
Abstract
We measure directed flow (v_{1}) for charged particles in Au+Au and Cu+Cu collisions at sqrt[s_{NN}]=200 and 62.4 GeV, as a function of pseudorapidity (eta), transverse momentum (p_{t}), and collision centrality, based on data from the STAR experiment. We find that the directed flow depends on the incident energy but, contrary to all available model implementations, not on the size of the colliding system at a given centrality. We extend the validity of the limiting fragmentation concept to v_{1} in different collision systems, and investigate possible explanations for the observed sign change in v_{1}(p_{t}).
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105
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Forward neutral-pion transverse single-spin asymmetries in p + p collisions at sqrt[s] = 200 GeV. PHYSICAL REVIEW LETTERS 2008; 101:222001. [PMID: 19113478 DOI: 10.1103/physrevlett.101.222001] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2008] [Indexed: 05/27/2023]
Abstract
We report precision measurements of the Feynman x (xF) dependence, and first measurements of the transverse momentum (pT) dependence, of transverse single-spin asymmetries for the production of pi0 mesons from polarized proton collisions at sqrt[s] = 200 GeV. The xF dependence of the results is in fair agreement with perturbative QCD model calculations that identify orbital motion of quarks and gluons within the proton as the origin of the spin effects. Results for the pT dependence at fixed xF are not consistent with these same perturbative QCD-based calculations.
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106
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Negative refractive index of metallic cross-I-shaped pairs: origin and evolution with pair gap width. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2008; 78:016605. [PMID: 18764072 DOI: 10.1103/physreve.78.016605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2008] [Indexed: 05/26/2023]
Abstract
A structured composite of the negative index of refraction was fabricated by one layer of cross-I-shaped metal pairs. In this structure, the electric and magnetic inclusions were effectively integrated into one small unit. We varied the spacing of the cross pair to control the location of the magnetic resonance mode and their intercoupling with the electric mode. The frequency dependences of permittivity, permeability, and refractive indices with different gap widths of the pairs were systematically discussed by free-space measurement as well as numerical simulation. A spacing window dependent on the geometrical parameters was found in which the real part of the refractive index could have a negative value. The one-layer cross-pair pattern proposed in this work can be extended to three-dimensional structures with well-controlled interlayer coupling that will greatly facilitate the fabrication and measurement of negative-index materials in high frequencies.
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107
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Longitudinal double-spin asymmetry for inclusive jet production in p[over -->] + p[over -->] collisions at sqrt[s]=200 GeV. PHYSICAL REVIEW LETTERS 2008; 100:232003. [PMID: 18643488 DOI: 10.1103/physrevlett.100.232003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2007] [Indexed: 05/26/2023]
Abstract
We report a new STAR measurement of the longitudinal double-spin asymmetry A(LL) for inclusive jet production at midrapidity in polarized p + p collisions at a center-of-mass energy of sqrt[s]=200 GeV. The data, which cover jet transverse momenta 5<p(T)<30 GeV/c, are substantially more precise than previous measurements. They provide significant new constraints on the gluon spin contribution to the nucleon spin through the comparison to predictions derived from one global fit to polarized deep-inelastic scattering measurements.
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108
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Measurement of transverse single-spin asymmetries for Dijet production in proton-proton collisions at sqrt[s]=200 GeV. PHYSICAL REVIEW LETTERS 2007; 99:142003. [PMID: 17930662 DOI: 10.1103/physrevlett.99.142003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2007] [Indexed: 05/25/2023]
Abstract
We report the first measurement of the opening angle distribution between pairs of jets produced in high-energy collisions of transversely polarized protons. The measurement probes (Sivers) correlations between the transverse spin orientation of a proton and the transverse momentum directions of its partons. With both beams polarized, the wide pseudorapidity (-1< or = eta < or = +2) coverage for jets permits separation of Sivers functions for the valence and sea regions. The resulting asymmetries are all consistent with zero and considerably smaller than Sivers effects observed in semi-inclusive deep inelastic scattering. We discuss theoretical attempts to reconcile the new results with the sizable transverse spin effects seen in semi-inclusive deep inelastic scattering and forward hadron production in pp collisions.
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109
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Partonic Flow and phi-Meson production in Au+Au collisions at sqrt radical sNN = 200 GeV. PHYSICAL REVIEW LETTERS 2007; 99:112301. [PMID: 17930430 DOI: 10.1103/physrevlett.99.112301] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2007] [Indexed: 05/25/2023]
Abstract
We present first measurements of the phi-meson elliptic flow (v2(pT)) and high-statistics pT distributions for different centralities from radical sNN=200 GeV Au+Au collisions at RHIC. In minimum bias collisions the v2 of the phi meson is consistent with the trend observed for mesons. The ratio of the yields of the Omega to those of the phi as a function of transverse momentum is consistent with a model based on the recombination of thermal s quarks up to pT approximately 4 GeV/c, but disagrees at higher momenta. The nuclear modification factor (R CP) of phi follows the trend observed in the K S 0 mesons rather than in Lambda baryons, supporting baryon-meson scaling. These data are consistent with phi mesons in central Au+Au collisions being created via coalescence of thermalized s quarks and the formation of a hot and dense matter with partonic collectivity at RHIC.
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110
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[Correlation of polycyclic aromatic hydrocarbons (PAHs) in PM10- phoenix tree leaves-soil system of a coking & chemical factory in Shanghai]. HUAN JING KE XUE= HUANJING KEXUE 2007; 28:1802-1805. [PMID: 17926414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
In order to study the distributions characteristics, sources and relationship of PAHs in PM10- phoenix tree leaves-soil system of a coking & chemical factory in Shanghai, the samples of PM10, phoenix tree leaves and soil around the factory were collected for a year. The concentration of PAHs were analyzed according to the USEPA method 8 000 series. The results showed that the average concentration of PAHs in PM10, phoenix tree leaves and soil were 101.11 ng/m3, 79.45 ng/g and 121.53 microg/g, respectively. Particulate phase (PM10) contained mainly carcinogenic and mutagenic PAHs, among which BaA, BghiP, Flu and BaP were found at significant concentrations. In phoenix tree leaves, Nap,Chy, BaP and BghiP presented a higher level of concentration. In soil, 3 and 4-ring PAHs presented a higher level. PAHs concentrations of phoenix tree leaves were very lower in May. Only Ace (0.16 ng/g) and Pyr (0.63 ng/g) were detected. In July and August the concentrations (39.19 ng/g and 150.94 ng/g, respectively) were uplifted significantly. It could be concluded PAHs was from petroleum and coal-fired compound source. There were very strong positive relationships of 16 PAHs level among phoenix tree leaves, soil and PM10 (p < 0.01).
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111
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Transverse momentum and centrality dependence of high-pT nonphotonic electron suppression in Au+Au collisions at sqrt[s NN]=200 GeV. PHYSICAL REVIEW LETTERS 2007; 98:192301. [PMID: 17677616 DOI: 10.1103/physrevlett.98.192301] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2006] [Revised: 01/15/2007] [Indexed: 05/16/2023]
Abstract
The STAR collaboration at the BNL Relativistic Heavy-Ion Collider (RHIC) reports measurements of the inclusive yield of nonphotonic electrons, which arise dominantly from semileptonic decays of heavy flavor mesons, over a broad range of transverse momenta (1.2<p(T)<10 GeV/c) in p+p, d+Au, and Au+Au collisions at sqrt[s_{NN}]=200 GeV. The nonphotonic electron yield exhibits an unexpectedly large suppression in central Au+Au collisions at high p(T), suggesting substantial heavy-quark energy loss at RHIC. The centrality and p(T) dependences of the suppression provide constraints on theoretical models of suppression.
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112
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Scaling properties of hyperon production in Au+Au collisions at square root [sNN]=200 GeV. PHYSICAL REVIEW LETTERS 2007; 98:062301. [PMID: 17358934 DOI: 10.1103/physrevlett.98.062301] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2006] [Indexed: 05/14/2023]
Abstract
We present the scaling properties of Lambda, Xi, and Omega in midrapidity Au+Au collisions at the Brookhaven National Laboratory Relativistic Heavy Ion Collider at sqrt[s_{NN}]=200 GeV. The yield of multistrange baryons per participant nucleon increases from peripheral to central collisions more rapidly than that of Lambda, indicating an increase of the strange-quark density of the matter produced. The strange phase-space occupancy factor gamma_{s} approaches unity for the most central collisions. Moreover, the nuclear modification factors of p, Lambda, and Xi are consistent with each other for 2<p_{T}<5 GeV/c in agreement with a scenario of hadron formation from constituent quark degrees of freedom.
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113
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Longitudinal double-spin asymmetry and cross section for inclusive jet production in polarized proton collisions at square root of s = 200 GeV. PHYSICAL REVIEW LETTERS 2006; 97:252001. [PMID: 17280342 DOI: 10.1103/physrevlett.97.252001] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2006] [Indexed: 05/13/2023]
Abstract
We report a measurement of the longitudinal double-spin asymmetry A(LL) and the differential cross section for inclusive midrapidity jet production in polarized proton collisions at square root of s = 200 GeV. The cross section data cover transverse momenta 5 < pT < 50 GeV/c and agree with next-to-leading order perturbative QCD evaluations. The A(LL) data cover 5 < pT < 17 GeV/c and disfavor at 98% C.L. maximal positive gluon polarization in the polarized nucleon.
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114
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Direct observation of dijets in central Au+Au collisions at sqrt[sNN]=200 GeV. PHYSICAL REVIEW LETTERS 2006; 97:162301. [PMID: 17155388 DOI: 10.1103/physrevlett.97.162301] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2006] [Indexed: 05/12/2023]
Abstract
The STAR Collaboration at the Relativistic Heavy Ion Collider reports measurements of azimuthal correlations of high transverse momentum (pT) charged hadrons in Au+Au collisions at higher pT than reported previously. As (pT) is increased, a narrow, back-to-back peak emerges above the decreasing background, providing a clear dijet signal for all collision centralities studied. Using these correlations, we perform a systematic study of dijet production and suppression in nuclear collisions, providing new constraints on the mechanisms underlying partonic energy loss in dense matter.
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115
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Identified baryon and meson distributions at large transverse momenta from Au + Au collisions at square root sNN=200 GeV. PHYSICAL REVIEW LETTERS 2006; 97:152301. [PMID: 17155321 DOI: 10.1103/physrevlett.97.152301] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2006] [Indexed: 05/12/2023]
Abstract
Transverse momentum spectra of pi+/-, p, and p up to 12 GeV/c at midrapidity in centrality selected Au + Au collisions at square root sNN=200 GeV are presented. In central Au + Au collisions, both pi +/- and p(p) show significant suppression with respect to binary scaling at pT approximately >4 GeV/c. Protons and antiprotons are less suppressed than pi+/-, in the range 1.5 approximately < pT approximately < 6 GeV/c. The pi-/pi+ and p/p ratios show at most a weak pT dependence and no significant centrality dependence. The p/pi ratios in central Au + Au collisions approach the values in p + p and d + Au collisions at pT approximately >5 GeV/c. The results at high pT indicate that the partonic sources of pi+/-, p, and p have similar energy loss when traversing the nuclear medium.
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116
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Forward neutral pion production in p + p and d + Au collisions at square root sNN=200 GeV. PHYSICAL REVIEW LETTERS 2006; 97:152302. [PMID: 17155322 DOI: 10.1103/physrevlett.97.152302] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2006] [Indexed: 05/12/2023]
Abstract
Measurements of the production of forward pi0 mesons from p + p and d + Au collisions at square root sNN=200 GeV are reported. The p + p yield generally agrees with next-to-leading order perturbative QCD calculations. The d + Au yield per binary collision is suppressed as eta increases, decreasing to approximately 30% of the p + p yield at eta =4.00, well below shadowing expectations. Exploratory measurements of azimuthal correlations of the forward pi0 with charged hadrons at eta approximately 0 show a recoil peak in p + p that is suppressed in d + Au at low pion energy. These observations are qualitatively consistent with a saturation picture of the low-x gluon structure of heavy nuclei.
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117
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Strange baryon resonance production in sqrt s NN=200 GeV p+p and Au+Au collisions. PHYSICAL REVIEW LETTERS 2006; 97:132301. [PMID: 17026027 DOI: 10.1103/physrevlett.97.132301] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2006] [Revised: 07/27/2006] [Indexed: 05/12/2023]
Abstract
We report the measurements of Sigma(1385) and Lambda(1520) production in p+p and Au+Au collisions at sqrt[s{NN}]=200 GeV from the STAR Collaboration. The yields and the p(T) spectra are presented and discussed in terms of chemical and thermal freeze-out conditions and compared to model predictions. Thermal and microscopic models do not adequately describe the yields of all the resonances produced in central Au+Au collisions. Our results indicate that there may be a time span between chemical and thermal freeze-out during which elastic hadronic interactions occur.
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118
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Distributions of charged hadrons associated with high transverse momentum particles in pp and Au+Au collisions at sqrt[sNN]=200 GeV. PHYSICAL REVIEW LETTERS 2005; 95:152301. [PMID: 16241721 DOI: 10.1103/physrevlett.95.152301] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2005] [Indexed: 05/05/2023]
Abstract
Charged hadrons in [EQUATION: SEE TEXT] associated with particles of [EQUATION: SEE TEXT] are reconstructed in pp and Au+Au collisions at sqrt[sNN]=200 GeV. The associated multiplicity and p magnitude sum are found to increase from pp to central Au+Au collisions. The associated p distributions, while similar in shape on the nearside, are significantly softened on the awayside in central Au+Au relative to pp and not much harder than that of inclusive hadrons. The results, consistent with jet quenching, suggest that the awayside fragments approach equilibration with the medium traversed.
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119
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Multistrange Baryon elliptic flow in Au+Au collisions at square root of sNN=200 GeV. PHYSICAL REVIEW LETTERS 2005; 95:122301. [PMID: 16197068 DOI: 10.1103/physrevlett.95.122301] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2005] [Indexed: 05/04/2023]
Abstract
We report on the first measurement of elliptic flow v2(pT) of multistrange baryons Xi- +Xi+ and Omega- + Omega+ in heavy-ion collisions. In minimum-bias Au+Au collisions at square root of s(NN)=200 GeV, a significant amount of elliptic flow, comparable to other nonstrange baryons, is observed for multistrange baryons which are expected to be particularly sensitive to the dynamics of the partonic stage of heavy-ion collisions. The pT dependence of v2 of the multistrange baryons confirms the number of constituent quark scaling previously observed for lighter hadrons. These results support the idea that a substantial fraction of the observed collective motion is developed at the early partonic stage in ultrarelativistic nuclear collisions at the Relativistic Heavy Ion Collider.
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120
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Multiplicity and pseudorapidity distributions of photons in Au+Au collisions at square root of (S(NN)) = 62.4 GeV. PHYSICAL REVIEW LETTERS 2005; 95:062301. [PMID: 16090941 DOI: 10.1103/physrevlett.95.062301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2005] [Revised: 04/12/2005] [Indexed: 05/03/2023]
Abstract
We present the first measurement of pseudorapidity distribution of photons in the region 2.3 < or = eta < or = 3.7 for different centralities in Au+Au collisions at square root of (S(NN)) = 62.4 GeV. We find that the photon yield scales with the number of participating nucleons at all collision centralities studied. The pseudorapidity distribution of photons, dominated by pi0 decays, has been compared to those of charged pions, photons, and inclusive charged particles from heavy-ion and nucleon-nucleon collisions at various energies. The photon production has been shown to be consistent with the energy and centrality independent limiting fragmentation scenario.
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121
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Open charm yields in d+Au collisions at squareroot[sNN]=200 GeV. PHYSICAL REVIEW LETTERS 2005; 94:062301. [PMID: 15783724 DOI: 10.1103/physrevlett.94.062301] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2004] [Indexed: 05/24/2023]
Abstract
Midrapidity open charm spectra from direct reconstruction of D0(D0)-->K-/+pi+/- in d+Au collisions and indirect electron-positron measurements via charm semileptonic decays in p+p and d+Au collisions at squareroot[sNN]=200 GeV are reported. The D0(D0) spectrum covers a transverse momentum (pT) range of 0.1<pT<3 GeV/c, whereas the electron spectra cover a range of 1<pT<4 GeV/c. The electron spectra show approximate binary collision scaling between p+p and d+Au collisions. From these two independent analyses, the differential cross section per nucleon-nucleon binary interaction at midrapidity for open charm production from d+Au collisions at BNL RHIC is dsigma(NN)cc/dy=0.30+/-0.04(stat)+/-0.09(syst) mb. The results are compared to theoretical calculations. Implications for charmonium results in A+A collisions are discussed.
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122
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Azimuthal anisotropy and correlations at large transverse momenta in p + p and Au + Au collisions at square root sNN=200 GeV. PHYSICAL REVIEW LETTERS 2004; 93:252301. [PMID: 15697893 DOI: 10.1103/physrevlett.93.252301] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2004] [Indexed: 05/24/2023]
Abstract
Results on high transverse momentum charged particle emission with respect to the reaction plane are presented for Au + Au collisions at square root s(NN)=200 GeV. Two- and four-particle correlations results are presented as well as a comparison of azimuthal correlations in Au + Au collisions to those in p + p at the same energy. The elliptic anisotropy v(2) is found to reach its maximum at p(t) approximately 3 GeV/c, then decrease slowly and remain significant up to p(t) approximately 7-10 GeV/c. Stronger suppression is found in the back-to-back high-p(t) particle correlations for particles emitted out of plane compared to those emitted in plane. The centrality dependence of v(2) at intermediate p(t) is compared to simple models based on jet quenching.
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123
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Multistrange baryon production in Au-Au collisions at sqrt[s(NN)]=130 GeV. PHYSICAL REVIEW LETTERS 2004; 92:182301. [PMID: 15169485 DOI: 10.1103/physrevlett.92.182301] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2003] [Indexed: 05/24/2023]
Abstract
The transverse mass spectra and midrapidity yields for Xis and Omegas are presented. For the 10% most central collisions, the (-)Xi(+)/h(-) ratio increases from the Super Proton Synchrotron to the Relativistic Heavy Ion Collider energies while the Xi(-)/h(-) stays approximately constant. A hydrodynamically inspired model fit to the Xi spectra, which assumes a thermalized source, seems to indicate that these multistrange particles experience a significant transverse flow effect, but are emitted when the system is hotter and the flow is smaller than values obtained from a combined fit to pi, K, p, and Lambdas.
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124
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Cross sections and transverse single-spin asymmetries in forward neutral-pion production from proton collisions at sqrt[s]=200 GeV. PHYSICAL REVIEW LETTERS 2004; 92:171801. [PMID: 15169138 DOI: 10.1103/physrevlett.92.171801] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2003] [Indexed: 05/24/2023]
Abstract
Measurements of the production of forward high-energy pi(0) mesons from transversely polarized proton collisions at sqrt[s]=200 GeV are reported. The cross section is generally consistent with next-to-leading order perturbative QCD calculations. The analyzing power is small at x(F) below about 0.3, and becomes positive and large at higher x(F), similar to the trend in data at sqrt[s]< or =20 GeV. The analyzing power is in qualitative agreement with perturbative QCD model expectations. This is the first significant spin result seen for particles produced with p(T)>1 GeV/c at a polarized proton collider.
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125
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Identified particle distributions in pp and Au+Au collisions at square root of (sNN)=200 GeV. PHYSICAL REVIEW LETTERS 2004; 92:112301. [PMID: 15089125 DOI: 10.1103/physrevlett.92.112301] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2003] [Indexed: 05/24/2023]
Abstract
Transverse mass and rapidity distributions for charged pions, charged kaons, protons, and antiprotons are reported for square root of [sNN]=200 GeV pp and Au+Au collisions at Relativistic Heary Ion Collider (RHIC). Chemical and kinetic equilibrium model fits to our data reveal strong radial flow and long duration from chemical to kinetic freeze-out in central Au+Au collisions. The chemical freeze-out temperature appears to be independent of initial conditions at RHIC energies.
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126
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Rho0 production and possible modification in Au+Au and p+p collisions at square root [sNN] = 200 GeV. PHYSICAL REVIEW LETTERS 2004; 92:092301. [PMID: 15089460 DOI: 10.1103/physrevlett.92.092301] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2003] [Indexed: 05/24/2023]
Abstract
We report results on rho(770)(0)-->pi(+)pi(-) production at midrapidity in p+p and peripheral Au+Au collisions at sqrt[s(NN)]=200 GeV. This is the first direct measurement of rho(770)(0)-->pi(+)pi(-) in heavy-ion collisions. The measured rho(0) peak in the invariant mass distribution is shifted by approximately 40 MeV/c(2) in minimum bias p+p interactions and approximately 70 MeV/c(2) in peripheral Au+Au collisions. The rho(0) mass shift is dependent on transverse momentum and multiplicity. The modification of the rho(0) meson mass, width, and shape due to phase space and dynamical effects are discussed.
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127
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Azimuthal anisotropy at the relativistic heavy ion collider: the first and fourth harmonics. PHYSICAL REVIEW LETTERS 2004; 92:062301. [PMID: 14995231 DOI: 10.1103/physrevlett.92.062301] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2003] [Indexed: 05/24/2023]
Abstract
We report the first observations of the first harmonic (directed flow, v(1)) and the fourth harmonic (v(4)), in the azimuthal distribution of particles with respect to the reaction plane in Au+Au collisions at the BNL Relativistic Heavy Ion Collider (RHIC). Both measurements were done taking advantage of the large elliptic flow (v(2)) generated at RHIC. From the correlation of v(2) with v(1) it is determined that v(2) is positive, or in-plane. The integrated v(4) is about a factor of 10 smaller than v(2). For the sixth (v(6)) and eighth (v(8)) harmonics upper limits on the magnitudes are reported.
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128
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Particle-type dependence of azimuthal anisotropy and nuclear modification of particle production in Au+Au collisions at square root of sNN=200 GeV. PHYSICAL REVIEW LETTERS 2004; 92:052302. [PMID: 14995300 DOI: 10.1103/physrevlett.92.052302] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2003] [Indexed: 05/24/2023]
Abstract
We present STAR measurements of the azimuthal anisotropy parameter v(2) and the binary-collision scaled centrality ratio R(CP) for kaons and lambdas (Lambda+Lambda) at midrapidity in Au+Au collisions at square root of s(NN)=200 GeV. In combination, the v(2) and R(CP) particle-type dependencies contradict expectations from partonic energy loss followed by standard fragmentation in vacuum. We establish p(T) approximately 5 GeV/c as the value where the centrality dependent baryon enhancement ends. The K(0)(S) and Lambda+Lambda v(2) values are consistent with expectations of constituent-quark-number scaling from models of hadron formation by parton coalescence or recombination.
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129
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Pion-Kaon correlations in central Au+Au collisions at square root [sNN] = 130 GeV. PHYSICAL REVIEW LETTERS 2003; 91:262302. [PMID: 14754044 DOI: 10.1103/physrevlett.91.262302] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2003] [Indexed: 05/24/2023]
Abstract
Pion-kaon correlation functions are constructed from central Au+Au STAR data taken at sqrt[s(NN)]=130 GeV by the STAR detector at the Relativistic Heavy Ion Collider (RHIC). The results suggest that pions and kaons are not emitted at the same average space-time point. Space-momentum correlations, i.e., transverse flow, lead to a space-time emission asymmetry of pions and kaons that is consistent with the data. This result provides new independent evidence that the system created at RHIC undergoes a collective transverse expansion.
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130
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Three-pion Hanbury Brown-Twiss correlations in relativistic heavy-ion collisions from the STAR experiment. PHYSICAL REVIEW LETTERS 2003; 91:262301. [PMID: 14754043 DOI: 10.1103/physrevlett.91.262301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2003] [Indexed: 05/24/2023]
Abstract
Data from the first physics run at the Relativistic Heavy-Ion Collider at Brookhaven National Laboratory, Au+Au collisions at sqrt[s(NN)]=130 GeV, have been analyzed by the STAR Collaboration using three-pion correlations with charged pions to study whether pions are emitted independently at freeze-out. We have made a high-statistics measurement of the three-pion correlation function and calculated the normalized three-particle correlator to obtain a quantitative measurement of the degree of chaoticity of the pion source. It is found that the degree of chaoticity seems to increase with increasing particle multiplicity.
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131
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Transverse-momentum and collision-energy dependence of high-pT hadron suppression in Au+Au collisions at ultrarelativistic energies. PHYSICAL REVIEW LETTERS 2003; 91:172302. [PMID: 14611336 DOI: 10.1103/physrevlett.91.172302] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2003] [Revised: 09/03/2003] [Indexed: 05/24/2023]
Abstract
We report high statistics measurements of inclusive charged hadron production in Au+Au and p+p collisions at sqrt[s(NN)]=200 GeV. A large, approximately constant hadron suppression is observed in central Au+Au collisions for 5<p(T)<12 GeV/c. The collision energy dependence of the yields and the centrality and p(T) dependence of the suppression provide stringent constraints on theoretical models of suppression. Models incorporating initial-state gluon saturation or partonic energy loss in dense matter are largely consistent with observations. We observe no evidence of p(T)-dependent suppression, which may be expected from models incorporating jet attenuation in cold nuclear matter or scattering of fragmentation hadrons.
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132
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Evidence from d+Au measurements for final-state suppression of high-p(T) hadrons in Au+Au collisions at RHIC. PHYSICAL REVIEW LETTERS 2003; 91:072304. [PMID: 12935009 DOI: 10.1103/physrevlett.91.072304] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2003] [Revised: 08/08/2003] [Indexed: 05/24/2023]
Abstract
We report measurements of single-particle inclusive spectra and two-particle azimuthal distributions of charged hadrons at high transverse momentum (high p(T)) in minimum bias and central d+Au collisions at sqrt[s(NN)]=200 GeV. The inclusive yield is enhanced in d+Au collisions relative to binary-scaled p+p collisions, while the two-particle azimuthal distributions are very similar to those observed in p+p collisions. These results demonstrate that the strong suppression of the inclusive yield and back-to-back correlations at high p(T) previously observed in central Au+Au collisions are due to final-state interactions with the dense medium generated in such collisions.
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133
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Production, purification and characterization of non-myristylated human T-cell protein tyrosine kinase in a baculovirus expression system. Gene 1996; 169:275-9. [PMID: 8647461 DOI: 10.1016/0378-1119(95)00817-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
A non-myristylated form (LCK M) of the human T-lymphocyte-specific protein tyrosine kinase (LCK) was produced at high levels in a baculovirus expression system (BVES) using two strategies. First, LCK M was produced by direct expression of a Gly2 --> Ala mutant of LCK. Second, LCK was produced as a glutathione S-transferase (GST) fusion, and LCK M was derived from the fusion protein by cleavage with thrombin. Both recombinant proteins (re-proteins) were produced at 5% of the total protein of infected Spodoptera frugiperda (Sf9) cells and were purified to >95% homogeneity. The enzymatic properties of the re-proteins and their inhibition by protein kinase inhibitors were comparable to the native enzyme (LCK N) derived from Jurkat cells and wild-type LCK derived from the BVES. The high production levels will facilitate the recovery of large quantities of re-protein for use in biochemical and biophysical studies.
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134
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Correlation functions and the disappearance of rotational collective motion in nucleus-nucleus collisions below 100 MeV/nucleon. PHYSICAL REVIEW. C, NUCLEAR PHYSICS 1995; 51:3256-3263. [PMID: 9970429 DOI: 10.1103/physrevc.51.3256] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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135
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Onset of multifragmentation in intermediate energy light asymmetrical collisions. PHYSICAL REVIEW. C, NUCLEAR PHYSICS 1995; 51:710-715. [PMID: 9970117 DOI: 10.1103/physrevc.51.710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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136
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Collective motion of reverse-reaction system in the intermediate-energy domain via the quantum-molecular-dynamics approach. PHYSICAL REVIEW. C, NUCLEAR PHYSICS 1995; 51:1029-1032. [PMID: 9970147 DOI: 10.1103/physrevc.51.1029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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137
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[Clinical observation of the effect of blood gas with two different methods of sputum suction]. ZHONGHUA HU LI ZA ZHI = CHINESE JOURNAL OF NURSING 1995; 30:7-9. [PMID: 7664371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The authors observed the preventive effect of the oxygen supplied double channel sucker on low blood oxygen. Thirty patients with channel sputum sucker under the mechanical respiratory support were taken as the contrast group, in comparison with the experimental group A and B respectively. Patients (n = 30) with one channel sputum sucking for 15 sec. were designated as experimental group A, while the other patients (n = 30) with the oxygen supplied double channel sucking for 15 sec were the group B, Blood gas analysis was done in every patient of each group. Significant difference of PO2 was found between group A and the contrast group (P < 0.01). No significant difference was found between group B and the contrast group (P > 0.05). It shows that oxygen supplied double channel sucker has preventive effect on low blood oxygen, and is suitable for sputum sucking in severe patients.
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138
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Isotropic fragmentation distribution of 129Xe on 90Zr and 197Au targets at intermediate energy. PHYSICAL REVIEW. C, NUCLEAR PHYSICS 1994; 50:2420-2423. [PMID: 9969930 DOI: 10.1103/physrevc.50.2420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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139
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Cardiac function and histological changes after non-dynamic cardiomyoplasty and preliminary study of dynamic cardiomyoplasty. Chin Med J (Engl) 1994; 107:836-9. [PMID: 7867391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
By means of histological method and ultrasound cardiographic (UCG) examination, the left-right ratio of transectional area of muscle fiber of latissimus dorsi muscle (LDM) after non-dynamic cardiomyoplasty was 77.4 +/- 11.7% in Group I (3 weeks after operation), and 78.4 +/- 11.6% atrophy and hyperplasia of LDM, but the basical structure was retained. The ejection fraction (EF) decreased significantly after operation (P < 0.05), but the difference between two groups was non- significant. Also, dynamic cardiomyoplasty was performed on a sheep. UCG showed the increased cardiac systolic function after operation. ATPase, succinodehydrogenase (SDH) and PAS examination implied the strengthening of fatigue-resistant ability in skeletal muscles after long-term electrical stimulation. So cardiomyoplasty is suggested to be a supplementary measure in treating end-stage heart failure.
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140
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Rotational behavior in intermediate energy heavy ion collisions. PHYSICAL REVIEW. C, NUCLEAR PHYSICS 1993; 48:R1492-R1496. [PMID: 9969068 DOI: 10.1103/physrevc.48.r1492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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141
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Study of the total reaction cross section via the reaction dynamical model. PHYSICAL REVIEW. C, NUCLEAR PHYSICS 1993; 48:850-856. [PMID: 9968896 DOI: 10.1103/physrevc.48.850] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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142
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Improved microscopic calculation of initial exciton number. PHYSICAL REVIEW. C, NUCLEAR PHYSICS 1993; 48:448-451. [PMID: 9968843 DOI: 10.1103/physrevc.48.448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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143
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Abstract
Previous studies have shown that embryonal carcinoma (EC) cells express the fibroblast growth factor k-FGF; however, there is a large decrease in the expression of this gene when EC cells differentiate. In addition, it has been shown that differentiation of mouse F9 EC cells reduces the expression of a reporter gene under the control of both the putative human k-FGF promoter and an enhancer-like element that is located in the third exon of the k-FGF gene. Given the low degree of sequence similarity between the human k-FGF gene and the murine k-FGF gene upstream of the transcription start site, it was unclear whether human sequences mimic fully the regulation of the k-FGF gene in mouse cells. To address this question, we have examined the expression of gene constructs containing various regions of the murine k-FGF gene in two mouse EC cell lines and one mouse embryonic stem (ES) cell line. Our results demonstrate that the mouse 5' flanking region, like the human 5' flanking region, cannot support expression of the reporter gene. In both EC cell lines and the ES cell line, expression of the reporter gene is elevated 10- to 100-fold by the addition of a 316-bp region taken from the third exon of the murine k-FGF gene. In addition, we provide evidence that octamer binding proteins are involved in the regulation of the k-FGF gene. Last, this study has identified regions upstream of the transcription start site that appear to regulate the expression of the murine k-FGF gene in EC cells and in ES cells.
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144
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[Study of the methodology for social psychological investigation of the personnel of an enterprise]. HUA XI YI KE DA XUE XUE BAO = JOURNAL OF WEST CHINA UNIVERSITY OF MEDICAL SCIENCES = HUAXI YIKE DAXUE XUEBAO 1988; 19:180-3. [PMID: 3198102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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145
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[An investigation of intelligence in 105 normal elderly people in Chengdu]. SICHUAN YI XUE YUAN XUE BAO = ACTA ACADEMIAE MEDICINAE SICHUAN 1985; 16:74-7. [PMID: 4012595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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