194 research outputs found
Intimate partner violence and risky sexual behaviors among Iranian women with substance use disorders
Background: Intimate partner violence (IPV) and risky sexual behaviors are serious and overlapping public health problems that disproportionately affect drug-involved women. Despite the fact that drug-using women experience extensive IPV, to date, no studies have investigated the association of IPV and risky sexual behaviors among drug-using women in Iran. Methods: Drug-using women (N =120) were recruited from a rehabilitation center in Tehran from March to October, 2009. The Revised Conflict Tactics Scale (CTS2), a standardized questionnaire, was used to collect data regarding violence. We used t-test and logistic regression models to explore the relationship between IPV domains and specific sexual risk behavior outcomes using SPSS 21. Results: The means (sd) for CTS2 domains were as follows: negotiation 4.29 (1.55), psychological violence 2.55 (1.51), sexual violence 0.37 (1.00), physical abuse 1.17 (1.49), injury 2.18 (1.97), and the mean total score was 1.69 (0.96). We found significantly higher injury scores, but lower sexual abuse scores among women with sexually-transmitted infection (STI) compared to women without STI (p-values 0.030 and <0.0001, respectively). In addition, we found that psychological abuse was positively associated with STI (p-value 0.03) and increased condom use (p = 0.010), possibly mediated through an increased likelihood of having multiple partners. Conclusion: The findings revealed that in Iran drug-involved women experience high rates of IPV and that IPV is associated with increased risky sexual behavior. Implication: Preventive interventions for violence that are integrated within drug treatment programs, as well as harm reduction programs are highly recommended
A Study of Parton Energy Loss in Au+Au Collisions at RHIC using Transport Theory
Parton energy loss in Au+Au collisions at RHIC energies is studied by
numerically solving the relativistic Boltzmann equation for the partons
including and collision
processes. Final particle spectra are obtained using two hadronization models;
the Lund string fragmentation and independent fragmentation models. Recent,
preliminary transverse momentum distributions from central Au+Au
collisions at RHIC are reproduced using gluon-gluon scattering cross sections
of 5-12 mb, depending upon the hadronization model. Comparisons with the HIJING
jet quenching algorithm are made.Comment: 6 pages, 6 figures, attached files are replaced (wrong files were
uploaded in version 1
A model for net-baryon rapidity distribution
In nuclear collisions, a sizable fraction of the available energy is carried
away by baryons. As the baryon number is conserved, the net-baryon
retains information on the energy-momentum carried by the incoming nuclei. A
simple and consistent model for net-baryon production in high energy
proton-proton and nucleus-nucleus collisions is presented. The basic
ingredients of the model are valence string formation based on standard PDFs
with QCD evolution and string fragmentation via the Schwinger mechanism. The
results of the model are presented and compared with data at different
centre-of-mass energies and centralities, as well as with existing models.
These results show that a good description of the main features of net-baryon
data is possible in the framework of a simplistic model, with the advantage of
making the fundamental production mechanisms manifest.Comment: 9 pages, 12 figures; in fig. 11 a) the vertical scale was correcte
What does your profile picture say about you?:the accuracy of thin-slice personality judgments from social networking sites made at zero-acquaintance
Jet Quenching and the p-bar >= pi- Anomaly at RHIC
PHENIX data on Au+Au at root(s)_= 130 AGeV suggest that p-bar yields may
exceed pi- at high p_T > 2 GeV/c. We propose that jet quenching in central
collisions suppresses the hard PQCD component of the spectra in central A+A
reactions, thereby exposing a novel component of baryon dynamics that we
attribute to (gluonic) baryon junctions. We predict that the observed p-bar >=
pi- and the p > pi+ anomaly at p_T ~ 2 GeV/c is limited to a finite p_T window
that decreases with increasing impact parameter.Comment: 5 pages, 4 figures, REVTeX, uses bbox.sty. Final version: references
and figures updated. Added discussion on the p/pi+ rati
Experimental and Theoretical Challenges in the Search for the Quark Gluon Plasma: The STAR Collaboration's Critical Assessment of the Evidence from RHIC Collisions
We review the most important experimental results from the first three years
of nucleus-nucleus collision studies at RHIC, with emphasis on results from the
STAR experiment, and we assess their interpretation and comparison to theory.
The theory-experiment comparison suggests that central Au+Au collisions at RHIC
produce dense, rapidly thermalizing matter characterized by: (1) initial energy
densities above the critical values predicted by lattice QCD for establishment
of a Quark-Gluon Plasma (QGP); (2) nearly ideal fluid flow, marked by
constituent interactions of very short mean free path, established most
probably at a stage preceding hadron formation; and (3) opacity to jets. Many
of the observations are consistent with models incorporating QGP formation in
the early collision stages, and have not found ready explanation in a hadronic
framework. However, the measurements themselves do not yet establish
unequivocal evidence for a transition to this new form of matter. The
theoretical treatment of the collision evolution, despite impressive successes,
invokes a suite of distinct models, degrees of freedom and assumptions of as
yet unknown quantitative consequence. We pose a set of important open
questions, and suggest additional measurements, at least some of which should
be addressed in order to establish a compelling basis to conclude definitively
that thermalized, deconfined quark-gluon matter has been produced at RHIC.Comment: 101 pages, 37 figures; revised version to Nucl. Phys.
Kaon Production and Kaon to Pion Ratio in Au+Au Collisions at \snn=130 GeV
Mid-rapidity transverse mass spectra and multiplicity densities of charged
and neutral kaons are reported for Au+Au collisions at \snn=130 GeV at RHIC.
The spectra are exponential in transverse mass, with an inverse slope of about
280 MeV in central collisions. The multiplicity densities for these particles
scale with the negative hadron pseudo-rapidity density. The charged kaon to
pion ratios are and
for the most central collisions. The ratio is lower than the same
ratio observed at the SPS while the is higher than the SPS result.
Both ratios are enhanced by about 50% relative to p+p and +p
collision data at similar energies.Comment: 6 pages, 3 figures, 1 tabl
Phi meson production in Au+Au and p+p collisions at sqrt (s)=200 GeV
We report the STAR measurement of Phi meson production in Au+Au and p+p
collisions at sqrt (s)=200 GeV. Using the event mixing technique, the Phi
spectra and yields are obtained at mid-rapidity for five centrality bins in
Au+Au collisions and for non-singly-diffractive p+p collisions. It is found
that the Phi transverse momentum distributions from Au+Au collisions are better
fitted with a single-exponential while the p+p spectrum is better described by
a double-exponential distribution. The measured nuclear modification factors
indicate that Phi production in central Au+Au collisions is suppressed relative
to peripheral collisions when scaled by the number of binary collisions. The
systematics of versus centrality and the constant Phi/K- ratio versus beam
species, centrality, and collision energy rule out kaon coalescence as the
dominant mechanism for Phi production.Comment: 6 pages, 3 figures, submitted to Phys. Rev. Let
Energy and system size dependence of \phi meson production in Cu+Cu and Au+Au collisions
We study the beam-energy and system-size dependence of \phi meson production
(using the hadronic decay mode \phi -- K+K-) by comparing the new results from
Cu+Cu collisions and previously reported Au+Au collisions at \sqrt{s_NN} = 62.4
and 200 GeV measured in the STAR experiment at RHIC. Data presented are from
mid-rapidity (|y|<0.5) for 0.4 < pT < 5 GeV/c. At a given beam energy, the
transverse momentum distributions for \phi mesons are observed to be similar in
yield and shape for Cu+Cu and Au+Au colliding systems with similar average
numbers of participating nucleons. The \phi meson yields in nucleus-nucleus
collisions, normalised by the average number of participating nucleons, are
found to be enhanced relative to those from p+p collisions with a different
trend compared to strange baryons. The enhancement for \phi mesons is observed
to be higher at \sqrt{s_NN} = 200 GeV compared to 62.4 GeV. These observations
for the produced \phi(s\bar{s}) mesons clearly suggest that, at these collision
energies, the source of enhancement of strange hadrons is related to the
formation of a dense partonic medium in high energy nucleus-nucleus collisions
and cannot be alone due to canonical suppression of their production in smaller
systems.Comment: 20 pages and 5 figure
Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC
Measurements of inclusive jet suppression in heavy ion collisions at the LHC
provide direct sensitivity to the physics of jet quenching. In a sample of
lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated
luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with
a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the
transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the
anti-kt algorithm with values for the distance parameter that determines the
nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of
the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp.
Jet production is found to be suppressed by approximately a factor of two in
the 10% most central collisions relative to peripheral collisions. Rcp varies
smoothly with centrality as characterized by the number of participating
nucleons. The observed suppression is only weakly dependent on jet radius and
transverse momentum. These results provide the first direct measurement of
inclusive jet suppression in heavy ion collisions and complement previous
measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables,
submitted to Physics Letters B. All figures including auxiliary figures are
available at
http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02
- âŠ