243 research outputs found
Group diversity and group identification:the moderating role of diversity beliefs
Research on diversity in teams and organizations has revealed ambiguous results regarding the effects of group composition on workgroup performance. The categorizationâelaboration model (van Knippenberg et al., 2004) accounts for this variety and proposes two different underlying processes. On the one hand diversity may bring about intergroup bias which leads to less group identification, which in turn is followed by more conflict and decreased workgroup performance. On the other hand, the information processing approach proposes positive effects of diversity because of a more elaborate processing of information brought about by a wider pool and variety of perspectives in more diverse groups. We propose that the former process is contingent on individual team members' beliefs that diversity is good or bad for achieving the team's aims. We predict that the relationship between subjective diversity and identification is more positive in ethnically diverse project teams when group members hold beliefs that are pro-diversity. Results of two longitudinal studies involving postgraduate students working in project teams confirm this hypothesis. Analyses further reveal that group identification is positively related to students' desire to stay in their groups and to their information elaboration. Finally, we found evidence for the expected moderated mediation model with indirect effects of subjective diversity on elaboration and the desire to stay, mediated through group identification, moderated by diversity beliefs
Electromagnetic probes
We introduce the seminal developments in the theory and experiments of
electromagnetic probes for the study of the dynamics of relativistic heavy ion
collisions and quark gluon plasma.Comment: 47 pages, 33 Figures; Lectures delivered by Dinesh K. Srivastava at
QGP Winter School (QGPWS08) at Jaipur, India, February 1-3, 200
Electron Scattering From High-Momentum Neutrons in Deuterium
We report results from an experiment measuring the semi-inclusive reaction
where the proton is moving at a large angle relative to the
momentum transfer. If we assume that the proton was a spectator to the reaction
taking place on the neutron in deuterium, the initial state of that neutron can
be inferred. This method, known as spectator tagging, can be used to study
electron scattering from high-momentum (off-shell) neutrons in deuterium. The
data were taken with a 5.765 GeV electron beam on a deuterium target in
Jefferson Laboratory's Hall B, using the CLAS detector. A reduced cross section
was extracted for different values of final-state missing mass ,
backward proton momentum and momentum transfer . The data
are compared to a simple PWIA spectator model. A strong enhancement in the data
observed at transverse kinematics is not reproduced by the PWIA model. This
enhancement can likely be associated with the contribution of final state
interactions (FSI) that were not incorporated into the model. A ``bound neutron
structure function'' was extracted as a function of and
the scaling variable at extreme backward kinematics, where effects of
FSI appear to be smaller. For MeV/c, where the neutron is far
off-shell, the model overestimates the value of in the region of
between 0.25 and 0.6. A modification of the bound neutron structure
function is one of possible effects that can cause the observed deviation.Comment: 33 pages RevTeX, 9 figures, to be submitted to Phys. Rev. C. Fixed 1
Referenc
Complete measurement of three-body photodisintegration of 3He for photon energies between 0.35 and 1.55 GeV
The three-body photodisintegration of 3He has been measured with the CLAS
detector at Jefferson Lab, using tagged photons of energies between 0.35 GeV
and 1.55 GeV. The large acceptance of the spectrometer allowed us for the first
time to cover a wide momentum and angular range for the two outgoing protons.
Three kinematic regions dominated by either two- or three-body contributions
have been distinguished and analyzed. The measured cross sections have been
compared with results of a theoretical model, which, in certain kinematic
ranges, have been found to be in reasonable agreement with the data.Comment: 22 pages, 25 eps figures, 2 tables, submitted to PRC. Modifications:
removed 2 figures, improvements on others, a few minor modifications to the
tex
A Kinematically Complete Measurement of the Proton Structure Function F2 in the Resonance Region and Evaluation of Its Moments
We measured the inclusive electron-proton cross section in the nucleon
resonance region (W < 2.5 GeV) at momentum transfers Q**2 below 4.5 (GeV/c)**2
with the CLAS detector. The large acceptance of CLAS allowed for the first time
the measurement of the cross section in a large, contiguous two-dimensional
range of Q**2 and x, making it possible to perform an integration of the data
at fixed Q**2 over the whole significant x-interval. From these data we
extracted the structure function F2 and, by including other world data, we
studied the Q**2 evolution of its moments, Mn(Q**2), in order to estimate
higher twist contributions. The small statistical and systematic uncertainties
of the CLAS data allow a precise extraction of the higher twists and demand
significant improvements in theoretical predictions for a meaningful comparison
with new experimental results.Comment: revtex4 18 pp., 12 figure
First measurement of direct photoproduction on the proton
We report on the results of the first measurement of exclusive
meson photoproduction on protons for GeV and GeV. Data were collected with the CLAS detector at the Thomas
Jefferson National Accelerator Facility. The resonance was detected via its
decay in the channel by performing a partial wave analysis of the
reaction . Clear evidence of the meson
was found in the interference between and waves at GeV. The -wave differential cross section integrated in the mass range of
the was found to be a factor of 50 smaller than the cross section
for the meson. This is the first time the meson has been
measured in a photoproduction experiment
Systematic reviews of observational studies of Risk of Thrombosis and Bleeding in General and Gynecologic Surgery (ROTBIGGS) : introduction and methodology
Funding Information: The Risk of Thrombosis and Bleeding in General and Gynecologic Surgery (ROTBIGGS) project was conducted by the Clinical Urology and Epidemiology (CLUE) Working Group and supported by the Academy of Finland (309387, 340957), Sigrid Jusélius Foundation and Competitive Research Funding of the Helsinki University Hospital (TYH2019321; TYH2020248). The sponsors had no role in the analysis and interpretation of the data or the manuscript preparation, review, or approval. Funding Information: KMA received a research grant from Astra Zeneca, and is consultant for Gedeon Richter, and received reimbursement for attending a scientific meeting from GSK (Tesaro Bio). RMT received reimbursement for attending a scientific meeting from Olympus. LIL, GHG, YL, RC, ALL, VJS, IEJK, PJK, RJC, RLA, KA, KMA, IB-L, MHB, JLC, SC, PJG, HAG-P, FZG, HAG, LH, MLI-K, KMJ, PKK, NK, TPK, AJK, TK, HL, AKM, BTN, TPN, CN, SMO, SP, NP, CBBR, ARR, TS, RMT, RWMV, YW, YX, LY, JH, and KAOT have no financial conflicts of interest. GHG and RC were panel members of the European Association of Urology (EAU) ad hoc Guideline on Thromboprophylaxis in Urological Surgery. KAOT was chair of the European Association of Urology (EAU) ad hoc Guideline on Thromboprophylaxis in Urological Surgery and panel member of the American Society of Hematology (ASH) Guideline Panel on Prevention of Venous Thromboembolism (VTE) in Surgical Hospitalized Patients. Publisher Copyright: © 2021, The Author(s).Background Venous thromboembolism (VTE) and bleeding are serious and potentially fatal complications of surgical procedures. Pharmacological thromboprophylaxis decreases the risk of VTE but increases the risk of major post-operative bleeding. The decision to use pharmacologic prophylaxis therefore represents a trade-off that critically depends on the incidence of VTE and bleeding in the absence of prophylaxis. These baseline risks vary widely between procedures, but their magnitude is uncertain. Systematic reviews addressing baseline risks are scarce, needed, and require innovations in methodology. Indeed, systematic summaries of these baseline risk estimates exist neither in general nor gynecologic surgery. We will fill this knowledge gap by performing a series of systematic reviews and meta-analyses of the procedure-specific and patient risk factor stratified risk estimates in general and gynecologic surgeries. Methods We will perform comprehensive literature searches for observational studies in general and gynecologic surgery reporting symptomatic VTE or bleeding estimates. Pairs of methodologically trained reviewers will independently assess the studies for eligibility, evaluate the risk of bias by using an instrument developed for this review, and extract data. We will perform meta-analyses and modeling studies to adjust the reported risk estimates for the use of thromboprophylaxis and length of follow up. We will derive the estimates of risk from the median estimates of studies rated at the lowest risk of bias. The primary outcomes are the risk estimates of symptomatic VTE and major bleeding at 4 weeks post-operatively for each procedure stratified by patient risk factors. We will apply the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach to rate evidence certainty. Discussion This series of systematic reviews, modeling studies, and meta-analyses will inform clinicians and patients regarding the trade-off between VTE prevention and bleeding in general and gynecologic surgeries. Our work advances the standards in systematic reviews of surgical complications, including assessment of risk of bias, criteria for arriving at the best estimates of risk (including modeling of the timing of events and dealing with suboptimal data reporting), dealing with subgroups at higher and lower risk of bias, and use of the GRADE approach. Systematic review registration PROSPERO CRD42021234119Peer reviewe
Exclusive meson electroproduction from hydrogen at CLAS
The longitudinal and transverse components of the cross section for the reaction were measured in Hall B at Jefferson
Laboratory using the CLAS detector. The data were taken with a 4.247 GeV
electron beam and were analyzed in a range of from 0.2 to 0.6 and of
from 1.5 to 3.0 GeV. The data are compared to a Regge model based on
effective hadronic degrees of freedom and to a calculation based on Generalized
Parton Distributions. It is found that the transverse part of the cross section
is well described by the former approach while the longitudinal part can be
reproduced by the latter.Comment: 6 pages, 4 figure
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