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Search: WFRF:(Lai J.) > (2005-2009)

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1.
  • Schael, S, et al. (author)
  • Precision electroweak measurements on the Z resonance
  • 2006
  • In: Physics Reports. - : Elsevier BV. - 0370-1573 .- 1873-6270. ; 427:5-6, s. 257-454
  • Research review (peer-reviewed)abstract
    • We report on the final electroweak measurements performed with data taken at the Z resonance by the experiments operating at the electron-positron colliders SLC and LEP. The data consist of 17 million Z decays accumulated by the ALEPH, DELPHI, L3 and OPAL experiments at LEP, and 600 thousand Z decays by the SLID experiment using a polarised beam at SLC. The measurements include cross-sections, forward-backward asymmetries and polarised asymmetries. The mass and width of the Z boson, m(Z) and Gamma(Z), and its couplings to fermions, for example the p parameter and the effective electroweak mixing angle for leptons, are precisely measured: m(Z) = 91.1875 +/- 0.0021 GeV, Gamma(Z) = 2.4952 +/- 0.0023 GeV, rho(l) = 1.0050 +/- 0.0010, sin(2)theta(eff)(lept) = 0.23153 +/- 0.00016. The number of light neutrino species is determined to be 2.9840 +/- 0.0082, in agreement with the three observed generations of fundamental fermions. The results are compared to the predictions of the Standard Model (SM). At the Z-pole, electroweak radiative corrections beyond the running of the QED and QCD coupling constants are observed with a significance of five standard deviations, and in agreement with the Standard Model. Of the many Z-pole measurements, the forward-backward asymmetry in b-quark production shows the largest difference with respect to its SM expectation, at the level of 2.8 standard deviations. Through radiative corrections evaluated in the framework of the Standard Model, the Z-pole data are also used to predict the mass of the top quark, m(t) = 173(+10)(+13) GeV, and the mass of the W boson, m(W) = 80.363 +/- 0.032 GeV. These indirect constraints are compared to the direct measurements, providing a stringent test of the SM. Using in addition the direct measurements of m(t) and m(W), the mass of the as yet unobserved SM Higgs boson is predicted with a relative uncertainty of about 50% and found to be less than 285 GeV at 95% confidence level. (c) 2006 Elsevier B.V. All rights reserved.
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2.
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3.
  • Adare, A., et al. (author)
  • Charged hadron multiplicity fluctuations in Au plus Au and Cu plus Cu collisions from s(NN)=22.5 to 200 GeV
  • 2008
  • In: Physical Review C (Nuclear Physics). - 0556-2813. ; 78:4
  • Journal article (peer-reviewed)abstract
    • A comprehensive survey of event-by-event fluctuations of charged hadron multiplicity in relativistic heavy ions is presented. The survey covers Au+Au collisions at s(NN)=62.4 and 200 GeV, and Cu+Cu collisions at s(NN)=22.5,62.4, and 200 GeV. Fluctuations are measured as a function of collision centrality, transverse momentum range, and charge sign. After correcting for nondynamical fluctuations due to fluctuations in the collision geometry within a centrality bin, the remaining dynamical fluctuations expressed as the variance normalized by the mean tend to decrease with increasing centrality. The dynamical fluctuations are consistent with or below the expectation from a superposition of participant nucleon-nucleon collisions based upon p+p data, indicating that this dataset does not exhibit evidence of critical behavior in terms of the compressibility of the system. A comparison of the data with a model where hadrons are independently emitted from a number of hadron clusters suggests that the mean number of hadrons per cluster is small in heavy ion collisions.
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4.
  • Adare, A., et al. (author)
  • Photon-hadron jet correlations in p plus p and Au plus Au collisions at s(NN)=200 GeV
  • 2009
  • In: Physical Review C (Nuclear Physics). - 0556-2813. ; 80:2
  • Journal article (peer-reviewed)abstract
    • We report the observation at the Relativistic Heavy Ion Collider of suppression of back-to-back correlations in the direct photon+jet channel in Au+Au relative to p+p collisions. Two-particle correlations of direct photon triggers with associated hadrons are obtained by statistical subtraction of the decay photon-hadron (gamma-h) background. The initial momentum of the away-side parton is tightly constrained, because the parton-photon pair exactly balance in momentum at leading order in perturbative quantum chromodynamics, making such correlations a powerful probe of the in-medium parton energy loss. The away-side nuclear suppression factor, I-AA, in central Au+Au collisions, is 0.32 +/- 0.12(stat)+/- 0.09(syst) for hadrons of 3 < p(T)(h)< 5 in coincidence with photons of 5 < p(T)(gamma)< 15 GeV/c. The suppression is comparable to that observed for high-p(T) single hadrons and dihadrons. The direct photon associated yields in p+p collisions scale approximately with the momentum balance, z(T)equivalent to p(T)(h)/p(T)(gamma), as expected for a measurement of the away-side parton fragmentation function. We compare to Au+Au collisions for which the momentum balance dependence of the nuclear modification should be sensitive to the path-length dependence of parton energy loss.
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5.
  • Adare, A., et al. (author)
  • System size and energy dependence of jet-induced hadron pair correlation shapes in Cu+Cu and Au+Au collisions at root S-NN 200 and 62.4 GeV
  • 2007
  • In: Physical Review Letters. - 1079-7114. ; 98:23
  • Journal article (peer-reviewed)abstract
    • We present azimuthal angle correlations of intermediate transverse momentum (1-4 GeV/c) hadrons from dijets in Cu+Cu and Au+Au collisions at root s(NN)=62.4 and 200 GeV. The away-side dijet induced azimuthal correlation is broadened, non-Gaussian, and peaked away from Delta phi=pi in central and semicentral collisions in all the systems. The broadening and peak location are found to depend upon the number of participants in the collision, but not on the collision energy or beam nuclei. These results are consistent with sound or shock wave models, but pose challenges to Cherenkov gluon radiation models.
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6.
  • Adare, A., et al. (author)
  • Cold nuclear matter effects on J/psi production as constrained by deuteron-gold measurements at root S-NN=200 GeV
  • 2008
  • In: Physical Review C (Nuclear Physics). - 0556-2813. ; 77:2, s. 15-024912
  • Journal article (peer-reviewed)abstract
    • We present a new analysis of J/psi production yields in deuteron-gold collisions at root s(NN) =200 GeV using data taken from the PHENIX experiment in 2003 and previously published in S. S. Adler [Phys. Rev. Lett 96, 012304 (2006)]. The high statistics proton-proton J/psi data taken in 2005 are used to improve the baseline measurement and thus construct updated cold nuclear matter modification factors (R-dAu). A suppression of J/psi in cold nuclear matter is observed as one goes forward in rapidity (in the deuteron-going direction), corresponding to a region more sensitive to initial-state low-x gluons in the gold nucleus. The measured nuclear modification factors are compared to theoretical calculations of nuclear shadowing to which a J/psi (or precursor) breakup cross section is added. Breakup cross sections of sigma(breakup)=2.8(-1.4)(+1.7) (2.2(-1.5)(+1.6)) mb are obtained by fitting these calculations to the data using two different models of nuclear shadowing. These breakup cross-section values are consistent within large uncertainties with the 4.2 +/- 0.5 mb determined at lower collision energies. Projecting this range of cold nuclear matter effects to copper-copper and gold-gold collisions reveals that the current constraints are not sufficient to firmly quantify the additional hot nuclear matter effect.
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7.
  • Adare, A., et al. (author)
  • Quantitative constraints on the transport properties of hot partonic matter from semi-inclusive single high transverse momentum pion suppression in Au plus Au collisions at root S-NN=200 GeV
  • 2008
  • In: Physical Review C (Nuclear Physics). - 0556-2813. ; 77:6
  • Journal article (peer-reviewed)abstract
    • The PHENIX experiment has measured the suppression of semi-inclusive single high-transverse-momentum pi(0)'s in Au+Au collisions at root s(NN) = 200 GeV. The present understanding of this suppression is in terms of energy loss of the parent (fragmenting) parton in a dense color-charge medium. We have performed a quantitative comparison between various parton energy-loss models and our experimental data. The statistical point-to-point uncorrelated as well as correlated systematic uncertainties are taken into account in the comparison. We detail this methodology and the resulting constraint on the model parameters, such as the initial color-charge density dN(g)/dy, the medium transport coefficient <(q) over cap >, or the initial energy-loss parameter epsilon(0). We find that high-transverse-momentum pi(0) suppression in Au+Au collisions has sufficient precision to constrain these model-dependent parameters at the +/- 20-25% (one standard deviation) level. These constraints include only the experimental uncertainties, and further studies are needed to compute the corresponding theoretical uncertainties.
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8.
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9.
  • Adare, A., et al. (author)
  • Correlated production of p and (p)over-bar in Au+Au collisions at root s(NN)=200 GeV
  • 2007
  • In: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 649:5-6, s. 359-369
  • Journal article (peer-reviewed)abstract
    • Correlations between p and (p) over bar at transverse momenta typical of enhanced baryon production in Au + Au collisions are reported. The PHENIX experiment has measured same and opposite sign baryon pairs in Au + Au collisions at root s(NN) = 200 GeV. Correlated production of p and p with the trigger particle from the range 2.5 < p(T) < 4.0 GeV/c and the associated particle with 1.8 < p(T) < 2.5 GeV/c is observed to be nearly independent of the centrality of the collisions. Same sign pairs show no correlation at any centrality. The conditional yield of mesons triggered by baryons (and anti-baryons) and mesons in the same p(T) range rises with increasing centrality, except for the most central collisions, where baryons show a significantly smaller number of associated mesons. These data are consistent with a picture in which hard scattered partons produce correlated p and (p) over bar in the p(T) region of the baryon excess. (c) 2007 Elsevier B.V. All rights reserved.
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10.
  • Adare, A., et al. (author)
  • Dihadron azimuthal correlations in Au+Au collisions at root s(NN)=200 GeV
  • 2008
  • In: Physical Review C (Nuclear Physics). - 0556-2813. ; 78:1
  • Journal article (peer-reviewed)abstract
    • Azimuthal angle (Delta phi) correlations are presented for a broad range of transverse momentum (0.4 < p(T) < 10 GeV/c) and centrality (0-92%) selections for charged hadrons from dijets in Au+Au collisions at root s(NN) = 200 GeV. With increasing p(T), the away-side Delta phi distribution evolves from a broad and relatively flat shape to a concave shape, then to a convex shape. Comparisons with p + p data suggest that the away-side distribution can be divided into a partially suppressed "head" region centered at Delta phi similar to pi, and an enhanced "shoulder" region centered at Delta phi similar to pi +/- 1.1. The p(T) spectrum for the associated hadrons in the head region softens toward central collisions. The spectral slope for the shoulder region is independent of centrality and trigger p(T). The properties of the near-side distributions are also modified relative to those in p + p collisions, reflected by the broadening of the jet shape in Delta phi and Delta eta, and an enhancement of the per-trigger yield. However, these modifications seem to be limited to p(T)less than or similar to 4 GeV/c, above which both the hadron pair shape and per-trigger yield become similar to p + p collisions. These observations suggest that both the away- and near-side distributions contain a jet fragmentation component which dominates for p(T) greater than or similar to 5 GeV/c and a medium-induced component which is important for p(T) less than or similar to 4 GeV/c. We also quantify the role of jets at intermediate and low p(T) through the yield of jet-induced pairs in comparison with binary scaled p + p pair yield. The yield of jet-induced pairs is suppressed at high pair proxy energy (sum of the p(T) magnitudes of the two hadrons) and is enhanced at low pair proxy energy. The former is consistent with jet quenching; the latter is consistent with the enhancement of soft hadron pairs due to transport of lost energy to lower p(T).
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11.
  • Adare, A., et al. (author)
  • Energy loss and flow of heavy quarks in Au+Au collisions at root s(NN) = 200 GeV
  • 2007
  • In: Physical Review Letters. - 1079-7114. ; 98:17
  • Journal article (peer-reviewed)abstract
    • The PHENIX experiment at the BNL Relativistic Heavy Ion Collider (RHIC) has measured electrons with 0.3 < p(T) < 9 GeV/c at midrapidity (y < 0.35) from heavy-flavor (charm and bottom) decays in Au + Au collisions at root s(NN) = 200 GeV. The nuclear modification factor R-AA relative to p + p collisions shows a strong suppression in central Au + Au collisions, indicating substantial energy loss of heavy quarks in the medium produced at RHIC energies. A large azimuthal anisotropy v(2) with respect to the reaction plane is observed for 0.5 < p(T) < 5 GeV/c indicating substantial heavy-flavor elliptic flow. Both R-AA and v(2) show a p(T) dependence different from those of neutral pions. A comparison to transport models which simultaneously describe R-AA(p(T)) and v(2)(p(T)) suggests that the viscosity to entropy density ratio is close to the conjectured quantum lower bound, i.e., near a perfect fluid.
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12.
  • Adare, A., et al. (author)
  • J/psi production versus centrality, transverse momentum, and rapidity in Au+Au collisions at root S(NN) = 200 GeV
  • 2007
  • In: Physical Review Letters. - 1079-7114. ; 98:23
  • Journal article (peer-reviewed)abstract
    • The PHENIX experiment at the BNL Relativistic Heavy Ion Collider (RHIC) has measured J/psi production for rapidities -2.2 < y < 2.2 in Au+Au collisions at root s(NN)=200 GeV. The J/psi invariant yield and nuclear modification factor R-AA as a function of centrality, transverse momentum, and rapidity are reported. A suppression of J/psi relative to binary collision scaling of proton-proton reaction yields is observed. Models which describe the lower energy J/psi data at the CERN Super Proton Synchrotron invoking only J/psi destruction based on the local medium density predict a significantly larger suppression at RHIC and more suppression at midrapidity than at forward rapidity. Both trends are contradicted by our data.
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13.
  • Adare, A., et al. (author)
  • Scaling properties of azimuthal anisotropy in Au plus Au and Cu plus Cu collisions at root s(NN)=200 GeV
  • 2007
  • In: Physical Review Letters. - 1079-7114. ; 98:16
  • Journal article (peer-reviewed)abstract
    • Differential measurements of elliptic flow (v(2)) for Au+Au and Cu+Cu collisions at root s(NN)=200 GeV are used to test and validate predictions from perfect fluid hydrodynamics for scaling of v(2) with eccentricity, system size, and transverse kinetic energy (KET). For KET equivalent to m(T)-m up to similar to 1 GeV the scaling is compatible with hydrodynamic expansion of a thermalized fluid. For large values of KET mesons and baryons scale separately. Quark number scaling reveals a universal scaling of v(2) for both mesons and baryons over the full KET range for Au+Au. For Au+Au and Cu+Cu the scaling is more pronounced in terms of KET, rather than transverse momentum.
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14.
  • Adare, A., et al. (author)
  • Transverse momentum and centrality dependence of dihadron correlations in Au plus Au collisions at root s(NN)=200 GeV: Jet quenching and the response of partonic matter
  • 2008
  • In: Physical Review C (Nuclear Physics). - 0556-2813. ; 77:1, s. 6-011901
  • Journal article (peer-reviewed)abstract
    • Azimuthal angle (Delta phi) correlations are presented for charged hadrons from dijets for 0.4 < p(T)< 10 GeV/c in Au+Au collisions at root s(NN)=200 GeV. With increasing p(T), the away-side distribution evolves from a broad and relatively flat shape to a concave shape, then to a convex shape. Comparisons to p+p data suggest that the away-side can be divided into a partially suppressed "head" region centered at Delta phi similar to pi and an enhanced "shoulder" region centered at Delta phi similar to pi +/- 1.1. The p(T) spectrum for the head region softens toward central collisions, consistent with the onset of jet quenching. The spectral slope for the shoulder region is independent of centrality and trigger p(T), which offers constraints on energy transport mechanisms and suggests that it contains the medium response to energetic jets.
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15.
  • Adare, A., et al. (author)
  • Measurement of Bottom Versus Charm as a Function of Transverse Momentum with Electron-Hadron Correlations in p plus p Collisions at s=200 GeV
  • 2009
  • In: Physical Review Letters. - 1079-7114. ; 103:8
  • Journal article (peer-reviewed)abstract
    • The momentum distribution of electrons from semileptonic decays of charm and bottom quarks for midrapidity |y|< 0.35 in p+p collisions at s=200 GeV is measured by the PHENIX experiment at the Relativistic Heavy Ion Collider over the transverse momentum range 2 < p(T)< 7 GeV/c. The ratio of the yield of electrons from bottom to that from charm is presented. The ratio is determined using partial D/D -> e(+/-)K(-/+)X (K unidentified) reconstruction. It is found that the yield of electrons from bottom becomes significant above 4 GeV/c in p(T). A fixed-order-plus-next-to-leading-log perturbative quantum chromodynamics calculation agrees with the data within the theoretical and experimental uncertainties. The extracted total bottom production cross section at this energy is sigma(bb)=3.2(-1.1)(+1.2)(stat)(-1.3)(+1.4)(syst)mu b.
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16.
  • Adare, A., et al. (author)
  • Onset of pi(0) Suppression Studied in Cu plus Cu Collisions at root s(NN)=22.4, 62.4, and 200 GeV
  • 2008
  • In: Physical Review Letters. - 1079-7114. ; 101:16
  • Journal article (peer-reviewed)abstract
    • Neutral pion transverse momentum (p(T)) spectra at midrapidity (|y| less than or similar to 0.35) were measured in Cu + Cu collisions at root s(NN) = 22.4, 62.4, and 200 GeV. Relative to pi(0) yields in p + p collisions scaled by the number of inelastic nucleon-nucleon collisions (N-coll) the pi(0) yields for p(T) greater than or similar to 2 GeV/c in central Cu + Cu collisions are suppressed at 62.4 and 200 GeV whereas an enhancement is observed at 22.4 GeV. A comparison with a jet-quenching model suggests that final state parton energy loss dominates in central Cu + Cu collisions at 62.4 and 200 GeV, while the enhancement at 22.4 GeV is consistent with nuclear modifications in the initial state alone.
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17.
  • Adare, A., et al. (author)
  • Dilepton mass spectra in p plus p collisions at root s=200 GeV
  • 2009
  • In: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 670:4-5, s. 313-320
  • Journal article (peer-reviewed)abstract
    • PHENIX has measured the electron-positron pair mass spectrum from 0 to 8 GeV/c(2) in p + p collisions at root s = 200 GeV. The contributions from light meson decays to e(+)e(-) pairs have been determined based on measurements of hadron production cross sections by PHENIX. Within the systematic uncertainty of similar to 20% they account for all e(+)e(-) pairs in the mass region below similar to 1 GeV/c(2). The e(+)e(-) pair yield remaining after subtracting these contributions is dominated by semileptonic decays of charmed hadrons correlated through flavor conservation. Using the spectral shape predicted by PYTHIA, we estimate the charm production cross section to be 544 +/- 39(stat) +/- 142(syst) +/- 200(model) pb. which is consistent with QCD calculations and measurements of single leptons by PHENIX. (C) 2008 Elsevier BV. All rights reserved.
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18.
  • Adare, A., et al. (author)
  • J/psi production in root s(NN)=200 GeV Cu+Cu collisions
  • 2008
  • In: Physical Review Letters. - 1079-7114. ; 101:12
  • Journal article (peer-reviewed)abstract
    • Yields for J/psi production in Cu+Cu collisions at root s(NN) = 200 GeV have been measured over the rapidity range |y|< 2.2 and compared with results in p+p and Au+Au collisions at the same energy. The Cu+Cu data offer greatly improved precision over existing Au+Au data for J/psi production in collisions with small to intermediate numbers of participants, in the range where the quark-gluon plasma transition threshold is predicted to lie. Cold nuclear matter estimates based on ad hoc fits to d+Au data describe the Cu+Cu data up to N-part similar to 50, corresponding to a Bjorken energy density of at least 1.5 GeV/fm(3).
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19.
  • Adare, A., et al. (author)
  • Measurement of High-p(T) single electrons from heavy-flavor decays in p+p collisions at root s=200 GeV
  • 2006
  • In: Physical Review Letters. - 1079-7114. ; 97:25
  • Journal article (peer-reviewed)abstract
    • The momentum distribution of electrons from decays of heavy flavor (charm and bottom) for midrapidity |y|< 0.35 in p+p collisions at s=200 GeV has been measured by the PHENIX experiment at the BNL Relativistic Heavy Ion Collider over the transverse momentum range 0.3 < p(T)< 9 GeV/c. Two independent methods have been used to determine the heavy-flavor yields, and the results are in good agreement with each other. A fixed-order-plus-next-to-leading-log perturbative QCD calculation agrees with the data within the theoretical and experimental uncertainties, with the data/theory ratio of 1.71 +/- 0.02(stat)+/- 0.18(sys) for 0.3 < p(T)< 9 GeV/c. The total charm production cross section at this energy has also been deduced to be sigma(cc)=567 +/- 57(stat)+/- 193(sys) mu b.
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20.
  • Adare, A., et al. (author)
  • Gluon-Spin Contribution to the Proton Spin from the Double-Helicity Asymmetry in Inclusive pi(0) Production in Polarized p plus p Collisions at root s=200 GeV
  • 2009
  • In: Physical Review Letters. - 1079-7114. ; 103:1
  • Journal article (peer-reviewed)abstract
    • The double helicity asymmetry in neutral pion production for p(T) = 1 to 12 GeV/c was measured with the PHENIX experiment to access the gluon-spin contribution, Delta G, to the proton spin. Measured asymmetries are consistent with zero, and at a theory scale of mu 2 = 4 GeV2 a next to leading order QCD analysis gives Delta G([0.02,0.3]) = 0.2, with a constraint of -0.7 < Delta G([0.02,0.3]) < 0.5 at Delta chi(2) = 9 (similar to 3 sigma) for the sampled gluon momentum fraction (x) range, 0.02 to 0.3. The results are obtained using predictions for the measured asymmetries generated from four representative fits to polarized deep inelastic scattering data. We also consider the dependence of the Delta G constraint on the choice of the theoretical scale, a dominant uncertainty in these predictions.
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21.
  • Adare, A., et al. (author)
  • Inclusive cross section and double helicity asymmetry for pi(0) production in p plus p collisions at root s=62.4 GeV
  • 2009
  • In: Physical Review D (Particles, Fields, Gravitation and Cosmology). - 1550-2368. ; 79:1
  • Journal article (peer-reviewed)abstract
    • The PHENIX experiment presents results from the RHIC 2006 run with polarized p + p collisions at root s = 62.4 GeV, for inclusive pi(0) production at midrapidity. Unpolarized cross section results are measured for transverse momenta p(T) = 0.5 to 7 GeV/c. Next-to-leading order perturbative quantum chromodynamics calculations are compared with the data, and while the calculations are consistent with the measurements, next-to-leading logarithmic corrections improve the agreement. Double helicity asymmetries A(LL) are presented for p(T) = 1 to 4 GeV/c and probe the higher range of Bjorken x of the gluon (x(g)) with better statistical precision than our previous measurements at root s = 200 GeV. These measurements are sensitive to the gluon polarization in the proton for 0.06 < x(g) < 0.4.
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22.
  • Adare, A., et al. (author)
  • J/psi production versus transverse momentum and rapidity in p+p collisions at root s=200 GeV
  • 2007
  • In: Physical Review Letters. - 1079-7114. ; 98:23
  • Journal article (peer-reviewed)abstract
    • J/psi production in p+p collisions at root s=200 GeV has been measured by the PHENIX experiment at the BNL Relativistic Heavy Ion Collider over a rapidity range of -2.2 < y < 2.2 and a transverse momentum range of 0 < p(T)< 9 GeV/c. The size of the present data set allows a detailed measurement of both the p(T) and the rapidity distributions and is sufficient to constrain production models. The total cross section times the branching ratio is B-ll sigma(J/psi)(pp)=178 +/- 3(stat)+/- 53(sys)+/- 18(norm) nb.
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23.
  • Ablikim, M., et al. (author)
  • Measurements of (XcJ)-> K+K-K+K- decays
  • 2006
  • In: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 642:3, s. 197-202
  • Journal article (peer-reviewed)abstract
    • Using 14M psi(2S) events taken with the BESII detector, chi(cJ) -> 2(K+K-) decays are studied. For the four-kaon final state, the branching fractions are B(chi(c0,1,2) ->.2(K+K-)) = (3.48 +/- 0.23 +/- 0.47) x 10(-3), (0.70 +/- 0.13 +/- 0.10) x 10(-3), and (2.17 +/- 0.20 +/- 0.31) x 10(-3). For the phi K+K- final state, the branching fractions, which are measured for the first time, are B(chi(c0,1,2) -> phi K+K-) = (1.03 +/- 0.22 +/- 0.15) x 10(-3), (0.46 +/- 0.16 +/- 0.06) x 10(-3), and (1.67 +/- 0.26 +/- 0.24) x 10(-4). For the phi phi final state, B(chi(c0,2) -> phi phi) = (0.94 +/- 0.21 +/- 0.13) x 10(-3) and (1.70 +/- 0.30 +/- 0.25) x 10(-3).
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24.
  • Zhou, Hua, et al. (author)
  • Design for Embedded Chinese Display Smart Card
  • 2006
  • In: 2006 Conference on High Density Microsystem Design and Packaging and Component Failure Analysis, HDP'06; Shanghai; China; 27 June 2006 through 28 June 2006. - 9781424404889 ; , s. 152-156
  • Conference paper (peer-reviewed)abstract
    • The storage and display of Chinese character data and the battery life are two bottle-necks of a Chinese display smart card which is one kind of super smart cards. This paper presented a new idea to realize the Chinese display which was a practice of embedded font solution. A dieform regular MCU, a smart card MCU and a graphical LCD controller(LCD driver) provided the main functions of the system to show Chinese characters on a graphical LCD panel, to receive operations from users and to run monitor program or, moreover, COS (Card Operating System). 2-Wire serial interface (TWI) was selected to be the communication protocol between the main MCU and the LCD controller in order to reduce the connection numbers and to enhance reliability. To minimize power consumption is one main design target for extending battery life. Besides selecting components with low power consumption, a power control scheme was designed to meet this requirement. A functional demonstrator was assembled in order to check the system desigh and to do the debug work.
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25.
  • Burén, Jonas, et al. (author)
  • Insulin action and signalling in fat and muscle from dexamethasone-treated rats
  • 2008
  • In: Archives of Biochemistry and Biophysics. - : Elsevier BV. - 0003-9861 .- 1096-0384. ; 474:1, s. 91-101
  • Journal article (peer-reviewed)abstract
    • Glucocorticoids initiate whole body insulin resistance and the aim of the present study was to investigate effects of dexamethasone on protein expression and insulin signalling in muscle and fat tissue. Rats were injected with dexamethasone (1mg/kg/day, i.p.) or placebo for 11 days before insulin sensitivity was evaluated in vitro in soleus and epitrochlearis muscles and in isolated epididymal adipocytes. Dexamethasone treatment reduced insulin-stimulated glucose uptake and glycogen synthesis by 30-70% in epitrochlearis and soleus, and insulin-stimulated glucose uptake by approximately 40% in adipocytes. 8-bromo-cAMP-stimulated lipolysis was approximately 2-fold higher in adipocytes from dexamethasone-treated rats and insulin was less effective to inhibit cAMP-stimulated lipolysis. A main finding was that dexamethasone decreased expression of PKB and insulin-stimulated Ser(473) and Thr(308) phosphorylation in both muscles and adipocytes. Expression of GSK-3 was not influenced by dexamethasone treatment in muscles or adipocytes and insulin-stimulated GSK-3beta Ser(9) phosphorylation was reduced in muscles only. A novel finding was that glycogen synthase (GS) Ser(7) phosphorylation was higher in both muscles from dexamethasone-treated rats. GS expression decreased (by 50%) in adipocytes only. Basal and insulin-stimulated GS Ser(641) and GS Ser(645,649,653,657) phosphorylation was elevated in epitrochlearis and soleus muscles and GS fractional activity was reduced correspondingly. In conclusion, dexamethasone treatment (1) decreases PKB expression and insulin-stimulated phosphorylation in both muscles and adipocytes, and (2) increases GS phosphorylation (reduces GS fractional activity) in muscles and decreases GS expression in adipocytes. We suggest PKB and GS as major targets for dexamethasone-induced insulin resistance.
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26.
  • Carlström, Mattias, et al. (author)
  • Nitric oxide deficiency and increased adenosine response of afferent arterioles in hydronephrotic mice with hypertension
  • 2008
  • In: Hypertension. - : American Heart Association. - 0194-911X .- 1524-4563. ; 51:5, s. 1386-1392
  • Research review (peer-reviewed)abstract
    • Afferent arterioles were used to investigate the role of adenosine, angiotensin II, NO, and reactive oxygen species in the pathogenesis of increased tubuloglomerular feedback response in hydronephrosis. Hydronephrosis was induced in wild-type mice, superoxide dismutase-1 overexpressed mice (superoxide-dismutase-1 transgenic), and deficient mice (superoxide dismutase-1 knockout). Isotonic contractions in isolated perfused arterioles and mRNA expression of NO synthase isoforms, adenosine, and angiotensin II receptors were measured. In wild-type mice, N(G)-nitro-L-arginine methyl ester (L-NAME) did not change the basal arteriolar diameter of hydronephrotic kidneys (-6%) but reduced it in control (-12%) and contralateral arterioles (-43%). Angiotensin II mediated a weaker maximum contraction of hydronephrotic arterioles (-18%) than in control (-42%) and contralateral arterioles (-49%). The maximum adenosine-induced constriction was stronger in hydronephrotic (-19%) compared with control (-8%) and contralateral kidneys (+/-0%). The response to angiotensin II became stronger in the presence of adenosine in hydronephrotic kidneys and attenuated in contralateral arterioles. L-NAME increased angiotensin II responses of all of the groups but less in hydronephrotic kidneys. The mRNA expression of endothelial NO synthase and inducible NO synthase was upregulated in the hydronephrotic arterioles. No differences were found for adenosine or angiotensin II receptors. In superoxide dismutase-1 transgenic mice, strong but similar L-NAME response (-40%) was observed for all of the groups. This response was totally abolished in arterioles of hydronephrotic superoxide dismutase-1 knockout mice. In conclusion, hydronephrosis is associated with changes in the arteriolar reactivity of both hydronephrotic and contralateral kidneys. Increased oxidative stress, reduced NO availability, and stronger reactivity to adenosine of the hydronephrotic kidney may contribute to the enhanced tubuloglomerular feedback responsiveness in hydronephrosis and be involved in the development of hypertension.
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27.
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28.
  • Forssén, Per-Erik, 1973-, et al. (author)
  • Informed Visual Search : Combining Attention and Object Recognition
  • 2008
  • In: Proceedings - IEEE International Conference on Robotics and Automation<em></em>. - Pasadena : IEEE Robotics and Automation Society. - 9781424416462 ; , s. 935-942
  • Conference paper (peer-reviewed)abstract
    • This paper studies the sequential object recognition problem faced by a mobile robot searching for specific objects within a cluttered environment. In contrast to current state-of-the-art object recognition solutions which are evaluated on databases of static images, the system described in this paper employs an active strategy based on identifying potential objects using an attention mechanism and planning to obtain images of these objects from numerous viewpoints. We demonstrate the use of a bag-of-features technique for ranking potential objects, and show that this measure outperforms geometric matching for invariance across viewpoints. Our system implements informed visual search by prioritising map locations and re-examining promising locations first. Experimental results demonstrate that our system is a highly competent object recognition system that is capable of locating numerous challenging objects amongst distractors.
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29.
  • Jankowski, V, et al. (author)
  • Uridine adenosine tetraphosphate acts as an autocrine hormone affecting glomerular filtration rate
  • 2008
  • In: Journal of Molecular Medicine. - : Springer Science and Business Media LLC. - 0946-2716 .- 1432-1440. ; 86:3, s. 333-340
  • Journal article (peer-reviewed)abstract
    • Recently, uridine adenosine tetraphosphate (Up(4)A) was described as a strong vasoconstrictor released from endothelial cells after stimulation with mechanical stress. In this study, we isolated and identified Up(4)A from kidney tissue, and we characterized the essential varying effects of Up(4)A on the afferent and efferent arterioles. Porcine and human kidney tissue was fractionated by size exclusion chromatography, affinity chromatography, anion exchange chromatography and reverse phase chromatography. In fractions purified to homogeneity, Up(4)A was identified by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS), MALDI-LIFT fragment mass spectrometry (MALDI-TOF/TOF MS), retention-time comparison and enzymatic cleavage analysis. We analysed the release of Up(4)A from cultivated renal proximal tubule cells after stimulation of protein kinase C with oleoyl-2-acetyl-sn-glycerol (OAG). Up(4)A was identified in renal tissue, and the effect of Up(4)A on the vascular tone of isolated perfused afferent and efferent arterioles was tested. Stimulation of tubule cells with OAG increased the release rate of Up(4)A from tubule cells about tenfold. Up(4)A acts as a strong vasoconstrictive mediator on afferent arterioles, but has no significant effect on the tone of efferent arterioles, suggesting a functional role of Up(4)A as an autocrine hormone for glomerular perfusion. Because of the predominant effect of the Up(4)A on afferent arterioles, we assume that Up(4)A may decrease glomerular perfusion, intra-glomerular pressure and, hence, glomerular filtration rate. The release of Up(4)A from renal tubular cells may be an additional mechanism whereby tubular cells could affect renal perfusion. Up(4)A release may further contribute to renal vascular autoregulation mechanisms. In conclusion, as Up(4)A occurs in renal tissue and has marked effects on afferent but not efferent arterioles, Up(4)A may play a role in renal hemodynamics and possibly blood pressure regulation.
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30.
  • Lai, I. H, et al. (author)
  • A unique tetrameric structure of deer plasma haptoglobin – an evolutionary advantage in the Hp 2-2 phenotype with homogeneous structure
  • 2008
  • In: FEBS Journal. - 1742-4658 .- 1742-464X. ; 275, s. 981-993
  • Journal article (peer-reviewed)abstract
    • Similar to blood types, human plasma haptoglobin (Hp) is classified intothree phenotypes: Hp 1-1, 2-1 and 2-2. They are genetically inheritedfrom two alleles Hp 1 and Hp 2 (represented in bold), but only theHp 1-1 phenotype is found in almost all animal species. The Hp 2-2protein consists of complicated large polymers cross-linked by a2-bsubunits or (a2-b)n (where n ‡ 3, up to 12 or more), and is associatedwith the risk of the development of diabetic, cardiovascular and inflammatorydiseases. In the present study, we found that deer plasma Hpmimics human Hp 2, containing a tandem repeat over the a-chain basedon our cloned cDNA sequence. Interestingly, the isolated deer Hp ishomogeneous and tetrameric, i.e. (a-b)4, although the locations of )SHgroups (responsible for the formation of polymers) are exactly identicalto that of human. Denaturation of deer Hp using 6 m urea under reducingconditions (143 mm b-mercaptoethanol), followed by renaturation,sustained the formation of (a-b)4, suggesting that the Hp tetramers arenot randomly assembled. Interestingly, an a-chain monoclonal antibody(W1), known to recognize both human and deer a-chains, only binds tointact human Hp polymers, but not to deer Hp tetramers. This impliesthat the epitope of the deer a-chain is no longer exposed on the surfacewhen Hp tetramers are formed. We propose that steric hindrance playsa major role in determining the polymeric formation in human and deerpolymers. Phylogenetic and immunochemical analyses revealed that theHp 2 allele of deer might have arisen at least 25 million years ago. Amechanism involved in forming Hp tetramers is proposed and discussed,and the possibility is raised that the evolved tetrameric structure of deerHp might confer a physiological advantage.
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31.
  • Liu, Fang, 1975, et al. (author)
  • Cyclic oxidation of two FeCrAlRE foils at 1100 oC - The influence of the concentration of minor alloying elements on scale microstructure
  • 2008
  • In: Materials Science Forum. - 1662-9752 .- 0255-5476. ; 595-598, s. 707-716
  • Conference paper (peer-reviewed)abstract
    • Two FeCrAlRE alloys, a commercial, 0C404, and a model alloy in the form of thin foils,with different Mn, Nb, Mo and Ti concentrations were subjected to cyclic oxidation in lab air at1100°C. The oxidized samples were studied by gravimetry, Grazing-Incidence X-ray Diffraction(GI-XRD), Scanning Transmission Electron Microscopy (STEM), and Energy Dispersive X-ray(EDX) analysis. The two FeCrAl alloys exhibit different oxidation kinetics; however, both alloyshave the same weight gain after 500 hours exposure. During the early stages the scale consistsmainly of α-Al2O3 together with some oxide particles containing Mn, Al, Fe and Cr formed on thealloys. After 500 hours the 0C404 scale locally also consists of larger polycrystalline regions ofMn-Cr-Al spinel. In addition, Si-rich oxide, chromia and Al-Cr oxide could be observed at themetal/oxide interface.
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32.
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33.
  • Malmer, Beatrice, et al. (author)
  • GLIOGENE an International Consortium to Understand Familial Glioma
  • 2007
  • In: Cancer epidemiology, biomarkers & prevention : a publication of the American Association for Cancer Research, cosponsored by the American Society of Preventive Oncology. - 1055-9965. ; 16:9, s. 1730-1734
  • Journal article (peer-reviewed)
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34.
  • Martinka, P, et al. (author)
  • Adenosine increases calcium sensitivity via receptor-independent activation of the p38/MK2 pathway in mesenteric arteries
  • 2008
  • In: Acta Physiologica. - : Wiley. - 1748-1708 .- 1748-1716. ; 193:1, s. 37-46
  • Journal article (peer-reviewed)abstract
    • AIM: Adenosine (Ado) restores desensitized angiotensin II-induced contractions in the renal arterioles via an intracellular, receptor-independent mechanisms including the p38 mitogen-activated protein kinase (MAPK). In the present study we test the hypothesis that MAPK-activated protein kinase 2 (MK2) mediates the Ado effect downstream from p38 MAPK resulting in an increased phosphorylation of the regulatory unit of the myosin light chain (MLC(20)). METHODS AND RESULTS: Contraction experiments were performed in rings of mesenteric arteries under isometric conditions in C57BL6 and MK2 knock out mice (MK2-/-). Ado pretreatment (10(-5) mol L(-1)) strongly increased Ang II sensitivity, calcium sensitivity and the phosphorylation of MLC(20). Treatment with Ado (3 x 10(-6) or 10(-5) mol L(-1) in between successive Ang II applications) enhanced the desensitized Ang II responses (second to fifth application). Ca(2+) transients were not effected by Ado. Further, blockade of type 1 and type 2 Ado receptors during treatment did not influence the effect. Type 3 receptor activation by inosine instead of Ado had no effect. Conversely, inhibition of nitrobenzylthioinosine-sensitive Ado transporters prevented the effects of Ado. Inhibition of p38 MAPK as well as use of MK2-/- mice prevented contractile Ado effects on the mesenteric arteries and the phosphorylation of MLC(20). CONCLUSION: The study shows that Ado activates the p38 MAPK/MK2 pathway in vascular smooth muscle via an intracellular action, which results in an increased MLC(20) phosphorylation in concert with increased calcium sensitivity of the contractile apparatus. This mechanism can significantly contribute to the regulation of vascular tone, e.g. under post-ischaemic conditions.
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35.
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36.
  • Meger, David, et al. (author)
  • Curious George : An Attentive Semantic Robot
  • 2008
  • In: Robotics and Autonomous Systems. - 0921-8890 .- 1872-793X. ; 56:6, s. 503-511
  • Journal article (peer-reviewed)abstract
    • State-of-the-art methods have recently achieved impressive performance for recognising the objects present in large databases of pre-collected images. There has been much less focus on building embodied systems that recognise objects present in the real world. This paper describes an intelligent system that attempts to perform robust object recognition in a realistic scenario, where a mobile robot moving through an environment must use the images collected from its camera directly to recognise objects. To perform successful recognition in this scenario, we have chosen a combination of techniques including a peripheral-foveal vision system, an attention system combining bottom-up visual saliency with structure from stereo, and a localisation and mapping technique. The result is a highly capable object recognition system that can be easily trained to locate the objects of interest in an environment, and subsequently build a spatial-semantic map of the region. This capability has been demonstrated during the Semantic Robot Vision Challenge, and is further illustrated with a demonstration of semantic mapping. We also empirically verify that the attention system outperforms an undirected approach even with a significantly lower number of foveations.
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37.
  • Mufti, A.A., et al. (author)
  • New Canadian highway bridge design code design provisions for fibre-reinforced structures
  • 2007
  • In: Canadian journal of civil engineering (Print). - 0315-1468 .- 1208-6029. ; 34:3, s. 267-283
  • Journal article (peer-reviewed)abstract
    • This paper presents a synthesis of the design provisions of the second edition of the Canadian Highway Bridge Design Code (CHBDC) for fibre-reinforced structures. New design provisions for applications not covered by the first edition of the CHBDC and the rationale for those that remain unchanged from the first edition are given. Among the new design provisions are those for glass-fibre-reinforced polymer as both primary reinforcement and tendons in concrete; and for the rehabilitation of concrete and timber structures with externally bonded fibre-reinforced-polymer (FRP) systems or near-surface-mounted reinforcement. The provisions for fibre-reinforced concrete deck slabs in the first edition have been reorganized in the second edition to explicitly include deck slabs of both cast-in-place and precast construction and are now referred to as externally restrained deck slabs, whereas deck slabs containing internal FRP reinforcement are referred to as internally restrained deck slabs. Resistance factors in the second edition have been recast from those in the first edition and depend on the condition of use, with a further distinction made between factory- and field-produced FRP. In the second edition, the deformability requirements for FRP-reinforced and FRP-prestressed concrete beams and slabs of the first edition have been split into three subclauses covering the design for deformability, minimum flexural resistance, and crack-control reinforcement. The effect of sustained loads on the strength of FRPs is accounted for in the second edition by limits on stresses in FRP at the serviceability limit state.
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38.
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39.
  • Orho-Melander, Marju, et al. (author)
  • Common Missense Variant in the Glucokinase Regulatory Protein Gene Is Associated With Increased Plasma Triglyceride and C-Reactive Protein but Lower Fasting Glucose Concentrations
  • 2008
  • In: Diabetes. - : American Diabetes Association. - 1939-327X .- 0012-1797. ; 57:11, s. 3112-3121
  • Journal article (peer-reviewed)abstract
    • OBJECTIVE-Using the genome-wide association approach, we recently identified the glucokinase regulatory protein gene (GCKR, rs780094) region as a novel quantitative trait locus for plasma triglyceride concentration in Europeans. Here, we sought to study the association of GCKR variants with metabolic phenotypes, including measures of glucose homeostasis, to evaluate the GCYR locus in samples of non-European ancestry and to fine-map across the associated genomic interval. RESEARCH DESIGN AND METHODS-We performed association studies in 12 independent cohorts comprising >45,000 individuals representing several ancestral groups (whites from Northern and Southern Europe, whites from the U.S., African Americans from the U.S., Hispanics of Caribbean origin, and Chinese, Malays, and Asian Indians from Singapore). We conducted genetic fine-mapping across the similar to 417-kb region of linkage disequilibrium. spanning GCKR and 16 other genes on chromosome 2p23 by imputing untyped HapMap single nucleotide polymorphisms (SNPs) and genotyping 104 SNPs across the associated genomic interval. RESULTS-We provide comprehensive evidence that GCYR rs780094 is associated with opposite effects on fasting plasma triglyceride (P-meta = 3 x 10(-56)) and glucose (P-meta = 1 x 10(-13)) concentrations. In addition, we confirmed recent reports that the same SNP is associated with C-reactive protein (CRP) level (P = 5 x 10(-5)). Both fine-mapping approaches revealed a common missense GCKR variant (rs1260326, Pro446Leu, 34% frequency, r(2) = 0.93 with rs780094) as the strongest association signal in the region. CONCLUSIONS-These findings point to a molecular mechanism in humans by which higher triglycerides and CRP can be coupled with lower plasma glucose concentrations and position GCKR in central pathways regulating both hepatic triglyceride and glucose metabolism. Diabetes 57:3112-3121, 2008
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40.
  • Perez-Martinez, Pablo, et al. (author)
  • Association between glucokinase regulatory protein (GCKR) and apolipoprotein A5 (APOA5) gene polymorphisms and triacylglycerol concentrations in fasting, postprandial, and fenofibrate-treated states
  • 2009
  • In: American Journal of Clinical Nutrition. - : Elsevier BV. - 1938-3207 .- 0002-9165. ; 89:1, s. 391-399
  • Journal article (peer-reviewed)abstract
    • Background: Hypertriglyceridemia is a risk factor for cardiovascular disease. Variation in the apolipoprotein A5 (APOA5) and glucokinase regulatory protein (GCKR) genes has been associated with fasting plasma triacylglycerol. Objective: We investigated the combined effects of the GCKR rs780094C -> T, APOA5 -1131T -> C, and APOA5 56C -> G single nucleotide polymorphisms (SNPs) on fasting triacylglycerol in several independent populations and the response to a high-fat meal and fenofibrate interventions. Design: We used a cross-sectional design to investigate the association with fasting triacylglycerol in 8 populations from America, Asia, and Europe (n = 7730 men and women) and 2 intervention studies in US whites (n = `1061) to examine postprandial triacylglycerol after a high-fat meal and the response to fenofibrate. We defined 3 combined genotype groups: 1) protective (homozygous for the wild-type allele for all 3 SNPs); 2) intermediate (any mixed genotype not included in groups 1 and 3); and 3) risk (carriers of the variant alleles at both genes). Results: Subjects within the risk group had significantly higher fasting triacylglycerol and a higher prevalence of hypertriglyceridemia than did subjects in the protective group across all populations. Moreover, subjects in the risk group had a greater postprandial triacylglycerol response to a high-fat meal and greater fenofibrate-induced reduction of fasting triacylglycerol than did the other groups, especially among persons with hypertriglyceridemia. Subjects with the intermediate genotype had intermediate values (P for trend < 0.001). Conclusions: SNPs in GCKR and APOA5 have an additive effect on both fasting and postprandial triacylglycerol and contribute to the interindividual variability in response to fenofibrate treatment. Am J Clin Nutr 2009;89:391-9. Clin Nutr 2009; 89: 391-9.
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