125 research outputs found

    A tribute to Stanley E. Seashore

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    http://deepblue.lib.umich.edu/bitstream/2027.42/86737/1/astannen-Tribute.pd

    Some Social Psychological Effects of Direct and Indirect Participation in Ten Swedish Companies

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    Sweden has introduced schemes of participation widely in its industrial and business organizations. We present in this article data concerning some of the social psychological effects of two forms of participation, indirect and direct, in ten Swedish factories. Indirect participation entails decision making through representatives of the employees; direct participation entails decision making by the employees them selves. Theories propose that participation has the effect of enhancing member reactions such as sense of commitment, favourable attitude and satisfaction in the company and of reducing dysfunctional reactions such as absenteeism. The data from these companies appear consistent with the above theories insofar as direct participation is concerned but not with respect to indirect participation. The data support the view that participation is likely to have the predicted effects on the reactions of members to the extent that participation is felt as a personal experience. Members are likely to feel committed and satisfied, first and foremost to the extent that they perceive themselves personally to have authority to make decisions; second, and in lesser degree, to the extent that they perceive their immediate work group to make decisions, and hardly at all to the extent that they perceive that decisions are made by representatives. These findings are consistent with conclusions drawn earlier by a number of researchers. They are inconsistent with the expectation underlying the laws of participation in Sweden (and in most other countries of Europe) insofar as these laws mandate indirect participation exclusively and are formulated with the expectation that such participation will have the positive psychological outcomes that many advocates of participation claim.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68871/2/10.1177_017084068300400303.pd

    Deciphering the properties of the medium produced in heavy ion collisions at RHIC by a pQCD analysis of quenched large pp_{\perp} π0\pi^0 spectra

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    We discuss the question of the relevance of perturbative QCD calculations for analyzing the properties of the dense medium produced in heavy ion collisions. Up to now leading order perturbative estimates have been worked out and confronted with data for quenched large pp_{\perp} hadron spectra. Some of them are giving paradoxical results, contradicting the perturbative framework and leading to speculations such as the formation of a strongly interacting quark-gluon plasma. Trying to bypass some drawbacks of these leading order analysis and without performing detailed numerical investigations, we collect evidence in favour of a consistent description of quenching and of the characteristics of the produced medium within the pQCD framework.Comment: 10 pages, 3 figure

    Recent results in relativistic heavy ion collisions: from ``a new state of matter'' to "the perfect fluid"

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    Experimental Physics with Relativistic Heavy Ions dates from 1992 when a beam of 197Au of energy greater than 10A GeV/c first became available at the Alternating Gradient Synchrotron (AGS) at Brookhaven National Laboratory (BNL) soon followed in 1994 by a 208Pb beam of 158A GeV/c at the Super Proton Synchrotron (SPS) at CERN (European Center for Nuclear Research). Previous pioneering measurements at the Berkeley Bevalac in the late 1970's and early 1980's were at much lower bombarding energies (~ 1 A GeV/c) where nuclear breakup rather than particle production is the dominant inelastic process in A+A collisions. More recently, starting in 2000, the Relativistic Heavy Ion Collider (RHIC) at BNL has produced head-on collisions of two 100A GeV beams of fully stripped Au ions, corresponding to nucleon-nucleon center-of-mass energy, sqrt(sNN)=200 GeV, total c.m. energy 200A GeV. The objective of this research program is to produce nuclear matter with extreme density and temperature, possibly resulting in a state of matter where the quarks and gluons normally confined inside individual nucleons (r < 1 fm) are free to act over distances an order of magnitude larger. Progress from the period 1992 to the present will be reviewed, with reference to previous results from light ion and proton-proton collisions where appropriate. Emphasis will be placed on the measurements which formed the basis for the announcements by the two major laboratories: "A new state of matter", by CERN on Feb 10, 2000 and "The perfect fluid", by BNL on April 19, 2005.Comment: 62 pages, 39 figures. Review article published in Reports on Progress in Physics on June 23, 2006. In this published version, mistakes, typographical errors, and citations have been corrected and a subsection has been adde

    Suppression of forward dilepton production from an anisotropic quark-gluon plasma

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    We calculate the rapidity dependence of leading-order medium dilepton yields resulting from a quark-gluon plasma which has a local time-dependent anisotropy in momentum space. We present a phenomenological model which includes temporal evolution of the plasma anisotropy parameter, xi, and the hard momentum scale, p_hard. Our model interpolates between 1+1 dimensional collisionally-broadened expansion at early times and 1+1 dimensional ideal hydrodynamic expansion at late times. Using our model, we find that at LHC energies, forward high-energy medium dilepton production would be suppressed by up to a factor of 3 if one assumes an isotropization/thermalization time of 2 fm/c. Therefore, it may be possible to use forward dilepton yields to experimentally determine the time of onset of locally isotropic hydrodynamic expansion of the quark-gluon plasma as produced in ultrarelativistic heavy-ion collisions.Comment: 12 pages, 5 figure

    Coordination and Output Attainment in Work Units Performing Non-routine Tasks: A Cross- National Study

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    Based on an information-processing perspective (Galbraith 1972), a theoretical pro position is advanced which predicts that for work units performing non-routine tasks, the effect of unit coordination on output attainment is contingent on the sources from which the unit acquires information for task performance. This proposition is tested using a cross-national research design. Data from four national samples — Austria, Belgium, Hungary, and Poland — of academic research units support the proposition. The results reinforce the need for a contingency approach to the study of coordination and performance in organizations. They also provide some insight into the interplay between society and organization.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68600/2/10.1177_017084068500600102.pd

    Early-Time Energy Loss in a Strongly-Coupled SYM Plasma

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    We carry out an analytic study of the early-time motion of a quark in a strongly-coupled maximally-supersymmetric Yang-Mills plasma, using the AdS/CFT correspondence. Our approach extracts the first thermal effects as a small perturbation of the known quark dynamics in vacuum, using a double expansion that is valid for early times and for (moderately) ultrarelativistic quark velocities. The quark is found to lose energy at a rate that differs significantly from the previously derived stationary/late-time result: it scales like T^4 instead of T^2, and is associated with a friction coefficient that is not independent of the quark momentum. Under conditions representative of the quark-gluon plasma as obtained at RHIC, the early energy loss rate is a few times smaller than its late-time counterpart. Our analysis additionally leads to thermally-corrected expressions for the intrinsic energy and momentum of the quark, in which the previously discovered limiting velocity of the quark is found to appear naturally.Comment: 39 pages, no figures. v2: Minor corrections and clarifications. References added. Version to be published in JHE

    Spin Structure of the Proton from Polarized Inclusive Deep-Inelastic Muon-Proton Scattering

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    We have measured the spin-dependent structure function g1pg_1^p in inclusive deep-inelastic scattering of polarized muons off polarized protons, in the kinematic range 0.003<x<0.70.003 < x < 0.7 and 1GeV2<Q2<60GeV21 GeV^2 < Q^2 < 60 GeV^2. A next-to-leading order QCD analysis is used to evolve the measured g1p(x,Q2)g_1^p(x,Q^2) to a fixed Q02Q^2_0. The first moment of g1pg_1^p at Q02=10GeV2Q^2_0 = 10 GeV^2 is Γp=0.136±0.013(stat.)±0.009(syst.)±0.005(evol.)\Gamma^p = 0.136\pm 0.013(stat.) \pm 0.009(syst.)\pm 0.005(evol.). This result is below the prediction of the Ellis-Jaffe sum rule by more than two standard deviations. The singlet axial charge a0a_0 is found to be 0.28±0.160.28 \pm 0.16. In the Adler-Bardeen factorization scheme, Δg2\Delta g \simeq 2 is required to bring ΔΣ\Delta \Sigma in agreement with the Quark-Parton Model. A combined analysis of all available proton and deuteron data confirms the Bjorken sum rule.Comment: 33 pages, 22 figures, uses ReVTex and smc.sty. submitted to Physical Review

    Screening in strongly coupled N=2* supersymmetric Yang-Mills plasma

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    Using gauge-gravity duality, we extend thermodynamic studies and present results for thermal screening masses in strongly coupled N=2* supersymmetric Yang-Mills theory. This non-conformal theory is a mass deformation of maximally supersymmetric N=4 gauge theory. Results are obtained for the entropy density, pressure, specific heat, equation of state, and screening masses, down to previously unexplored low temperatures. The temperature dependence of screening masses in various symmetry channels, which characterize the longest length scales over which thermal fluctuations in the non-Abelian plasma are correlated, is examined and found to be asymptotically linear in the low temperature regime.Comment: 43 pages, 13 figures, typo fixed, published versio
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