741 research outputs found
1079-79 The impact of aortic manipulation on neurological outcomes after coronary artery bypass surgery: A risk-adjusted study
Chronologic distribution of stroke after minimally invasive versus conventional coronary artery bypass
AbstractObjectivesWe sought to investigate whether the chronologic distribution of the onset of stroke occurring after coronary artery bypass graft surgery (CABG) without cardiopulmonary bypass (off-pump CABG) is different from the conventional on-pump approach (CABG with cardiopulmonary bypass).BackgroundOff-pump CABG has been associated with a lower stroke rate, compared with conventional on-pump CABG. However, it is unknown whether the chronologic distribution of the onset of stroke is different between the two approaches.MethodsWe evaluated the chronologic distribution of postoperative stroke in patients undergoing CABG from June 1996 to August 2001 (n = 10,573). Preoperative risk factors for stroke were identified using the Northern New England preoperative estimate of stroke risk. Multivariate logistic regression analysis was used to determine the independent predictors of early stroke and to delineate the association between the surgical approach and the chronologic distribution of the onset of stroke.ResultsStroke occurred in 217 patients (2%, n = 10,573). A total of 44 (20%) and 173 (80%) of these patients had stroke after off-pump CABG and on-pump CABG, respectively. The median time for the onset of stroke was two days (range 0 to 11 days) after on-pump CABG versus four days (range 0 to 14 days) after off-pump CABG (p < 0.01). On-pump CABG was associated with a higher risk of early stroke (odds ratio 5.3, 95% confidence interval 2.6 to 10.9; p < 0.01) compared with off-pump CABG.ConclusionsCompared with off-pump CABG, on-pump CABG is associated with an earlier onset of postoperative stroke during the recovery phase, suggesting different mechanisms in the pathogenesis of stroke between the two surgical approaches
Optical Intraday Variability Studies of Ten Low Energy Peaked Blazars
We have carried out optical (R band) intraday variability (IDV) monitoring of
a sample of ten bright low energy peaked blazars (LBLs). Forty photometric
observations, of an average of ~ 4 hours each, were made between 2008 September
and 2009 June using two telescopes in India. Measurements with good signal to
noise ratios were typically obtained within 1-3 minutes, allowing the detection
of weak, fast variations using N-star differential photometry. We employed both
structure function and discrete correlation function analysis methods to
estimate any dominant timescales of variability and found that in most of the
cases any such timescales were longer than the duration of the observation. The
calculated duty cycle of IDV in LBLs during our observing run is ~ 52%, which
is low compared to many earlier studies; however, the relatively short periods
for which each source was observed can probably explain this difference. We
briefly discuss possible emission mechanisms for the observed variability.Comment: 20 Pages, 9 Figures, 4 Tables, accepted for publication in MNRA
“A Cathartic Moment in a Man’s Life”: Homosociality and Gendered Fun on the Puttan Tour
Rarely addressed in academic scholarship, the puttan tour is a well-known form of entertainment in Italy where young men drive around in small groups with the aim of spotting street sex workers. On some occasions, the participants will approach the sex workers to strike up a conversation. On others, they will shout out insults from their car then drive away. This article aims to advance a detailed analysis of this underexplored cultural practice drawing on a diverse body of scholarship exploring the intersection of masculinity, leisure, and homosociality. By analyzing stories of puttan tours gathered mostly online, including written accounts and YouTube videos, our aim is to explore the appeal of the puttan tour through an analysis of how homosociality, humor, and laughter operate in this example of gendered fun. To this end, we look at the multiple and often equivocal meanings of this homosocial male-bonding ritual, its emotional and affective dynamics, and the ways in which it reproduces structures of inequality while normalizing violence against sex workers
Measurement of inclusive D*+- and associated dijet cross sections in photoproduction at HERA
Inclusive photoproduction of D*+- mesons has been measured for photon-proton
centre-of-mass energies in the range 130 < W < 280 GeV and a photon virtuality
Q^2 < 1 GeV^2. The data sample used corresponds to an integrated luminosity of
37 pb^-1. Total and differential cross sections as functions of the D*
transverse momentum and pseudorapidity are presented in restricted kinematical
regions and the data are compared with next-to-leading order (NLO) perturbative
QCD calculations using the "massive charm" and "massless charm" schemes. The
measured cross sections are generally above the NLO calculations, in particular
in the forward (proton) direction. The large data sample also allows the study
of dijet production associated with charm. A significant resolved as well as a
direct photon component contribute to the cross section. Leading order QCD
Monte Carlo calculations indicate that the resolved contribution arises from a
significant charm component in the photon. A massive charm NLO parton level
calculation yields lower cross sections compared to the measured results in a
kinematic region where the resolved photon contribution is significant.Comment: 32 pages including 6 figure
Measurement of Jet Shapes in Photoproduction at HERA
The shape of jets produced in quasi-real photon-proton collisions at
centre-of-mass energies in the range GeV has been measured using the
hadronic energy flow. The measurement was done with the ZEUS detector at HERA.
Jets are identified using a cone algorithm in the plane with a
cone radius of one unit. Measured jet shapes both in inclusive jet and dijet
production with transverse energies GeV are presented. The jet
shape broadens as the jet pseudorapidity () increases and narrows
as increases. In dijet photoproduction, the jet shapes have been
measured separately for samples dominated by resolved and by direct processes.
Leading-logarithm parton-shower Monte Carlo calculations of resolved and direct
processes describe well the measured jet shapes except for the inclusive
production of jets with high and low . The observed
broadening of the jet shape as increases is consistent with the
predicted increase in the fraction of final state gluon jets.Comment: 29 pages including 9 figure
High-E_T dijet photoproduction at HERA
The cross section for high-E_T dijet production in photoproduction has been
measured with the ZEUS detector at HERA using an integrated luminosity of 81.8
pb-1. The events were required to have a virtuality of the incoming photon,
Q^2, of less than 1 GeV^2 and a photon-proton centre-of-mass energy in the
range 142 < W < 293 GeV. Events were selected if at least two jets satisfied
the transverse-energy requirements of E_T(jet1) > 20 GeV and E_T(jet2) > 15 GeV
and pseudorapidity requirements of -1 < eta(jet1,2) < 3, with at least one of
the jets satisfying -1 < eta(jet) < 2.5. The measurements show sensitivity to
the parton distributions in the photon and proton and effects beyond
next-to-leading order in QCD. Hence these data can be used to constrain further
the parton densities in the proton and photon.Comment: 36 pages, 13 figures, 20 tables, including minor revisions from
referees. Accepted by Phys. Rev.
Measurement of the diffractive structure function in deep inelastic scattering at HERA
This paper presents an analysis of the inclusive properties of diffractive
deep inelastic scattering events produced in interactions at HERA. The
events are characterised by a rapidity gap between the outgoing proton system
and the remaining hadronic system. Inclusive distributions are presented and
compared with Monte Carlo models for diffractive processes. The data are
consistent with models where the pomeron structure function has a hard and a
soft contribution. The diffractive structure function is measured as a function
of \xpom, the momentum fraction lost by the proton, of , the momentum
fraction of the struck quark with respect to \xpom, and of . The \xpom
dependence is consistent with the form \xpoma where
in all bins of and
. In the measured range, the diffractive structure function
approximately scales with at fixed . In an Ingelman-Schlein type
model, where commonly used pomeron flux factor normalisations are assumed, it
is found that the quarks within the pomeron do not saturate the momentum sum
rule.Comment: 36 pages, latex, 11 figures appended as uuencoded fil
An NLO QCD analysis of inclusive cross-section and jet-production data from the ZEUS experiment
The ZEUS inclusive differential cross-section data from HERA, for charged and
neutral current processes taken with e+ and e- beams, together with
differential cross-section data on inclusive jet production in e+ p scattering
and dijet production in \gamma p scattering, have been used in a new NLO QCD
analysis to extract the parton distribution functions of the proton. The input
of jet data constrains the gluon and allows an accurate extraction of
\alpha_s(M_Z) at NLO;
\alpha_s(M_Z) = 0.1183 \pm 0.0028(exp.) \pm 0.0008(model)
An additional uncertainty from the choice of scales is estimated as \pm
0.005. This is the first extraction of \alpha_s(M_Z) from HERA data alone.Comment: 37 pages, 14 figures, to be submitted to EPJC. PDFs available at
http://durpdg.dur.ac.uk/hepdata in LHAPDFv
Measurement of event shapes in deep inelastic scattering at HERA
Inclusive event-shape variables have been measured in the current region of
the Breit frame for neutral current deep inelastic ep scattering using an
integrated luminosity of 45.0 pb^-1 collected with the ZEUS detector at HERA.
The variables studied included thrust, jet broadening and invariant jet mass.
The kinematic range covered was 10 < Q^2 < 20,480 GeV^2 and 6.10^-4 < x < 0.6,
where Q^2 is the virtuality of the exchanged boson and x is the Bjorken
variable. The Q dependence of the shape variables has been used in conjunction
with NLO perturbative calculations and the Dokshitzer-Webber non-perturbative
corrections (`power corrections') to investigate the validity of this approach.Comment: 7+25 pages, 6 figure
- …