537 research outputs found
Clinical characteristics and outcomes of clostridial bacteraemia in cancer patients
AbstractClostridial bacteraemia is usually associated with substantial morbidity and mortality in cancer patients. However, clinical characteristics and risk factors for early mortality in this population are poorly described. We retrospectively studied cancer patients with clostridial bacteraemia treated between January 1996 and December 2011. We compared clinical manifestations between patients with solid tumour and haematological malignancy and assessed risk factors for 7-day mortality. In all, 164 cancer patients developed clostridial bacteraemia during the study period—85 (52%) with solid tumour and 79 (48%) with haematological malignancy. Common isolates were Clostridium perfringens (27%), Clostridium septicum (19%) and Clostridium tertium (14%). Solid tumour malignancy patients were more likely to have a focal gastrointestinal source for bacteraemia and were more likely to undergo subsequent surgery. Haematological malignancy patients were more often neutropenic and more often had no focal source of bacteraemia. Seven-day mortality was 20% (33/164) and did not vary based on malignancy type. The adjusted odds ratio of dying within 7 days of clostridial bacteraemia among patients with hypotension (40/164) was 7.2 (95% CI, 2.9–18.1) and in patients with acute haemolysis (7/164) was 10.5 (95% CI, 1.3–85.2). Clostridial species also impacted mortality; no patient with C. tertium bacteraemia died within 7 days. In conclusion, clinical manifestations of clostridial bacteraemia differed between patients with solid tumour and haematological malignancy, but 7-day mortality was similar. Patients with hypotension and haemolysis at time of bacteraemia were at increased risk for early death
Azimuthal Correlations in the Target Fragmentation Region of High Energy Nuclear Collisions
Results on the target mass dependence of proton and pion pseudorapidity
distributions and of their azimuthal correlations in the target rapidity range
are presented. The data have been taken with the
Plastic-Ball detector set-up for 4.9 GeV p + Au collisions at the Berkeley
BEVALAC and for 200 GeV/ p-, O-, and S-induced reactions on
different nuclei at the CERN-SPS. The yield of protons at backward rapidities
is found to be proportional to the target mass. Although protons show a typical
``back-to-back'' correlations, a ``side-by-side'' correlation is observed for
positive pions, which increases both with target mass and with impact parameter
of a collision. The data can consistently be described by assuming strong
rescattering phenomena including pion absorption effects in the entire excited
target nucleus.Comment: 7 pages, figures included, complete postscript available at
ftp://qgp.uni-muenster.de/pub/paper/azi-correlations.ps submitted to Phys.
Lett.
Evidence of Color Coherence Effects in W+jets Events from ppbar Collisions at sqrt(s) = 1.8 TeV
We report the results of a study of color coherence effects in ppbar
collisions based on data collected by the D0 detector during the 1994-1995 run
of the Fermilab Tevatron Collider, at a center of mass energy sqrt(s) = 1.8
TeV. Initial-to-final state color interference effects are studied by examining
particle distribution patterns in events with a W boson and at least one jet.
The data are compared to Monte Carlo simulations with different color coherence
implementations and to an analytic modified-leading-logarithm perturbative
calculation based on the local parton-hadron duality hypothesis.Comment: 13 pages, 6 figures. Submitted to Physics Letters
Measurement of the p-pbar -> Wgamma + X cross section at sqrt(s) = 1.96 TeV and WWgamma anomalous coupling limits
The WWgamma triple gauge boson coupling parameters are studied using p-pbar
-> l nu gamma + X (l = e,mu) events at sqrt(s) = 1.96 TeV. The data were
collected with the DO detector from an integrated luminosity of 162 pb^{-1}
delivered by the Fermilab Tevatron Collider. The cross section times branching
fraction for p-pbar -> W(gamma) + X -> l nu gamma + X with E_T^{gamma} > 8 GeV
and Delta R_{l gamma} > 0.7 is 14.8 +/- 1.6 (stat) +/- 1.0 (syst) +/- 1.0 (lum)
pb. The one-dimensional 95% confidence level limits on anomalous couplings are
-0.88 < Delta kappa_{gamma} < 0.96 and -0.20 < lambda_{gamma} < 0.20.Comment: Submitted to Phys. Rev. D Rapid Communication
Measurement of the ttbar Production Cross Section in ppbar Collisions at sqrt{s} = 1.96 TeV using Kinematic Characteristics of Lepton + Jets Events
We present a measurement of the top quark pair ttbar production cross section
in ppbar collisions at a center-of-mass energy of 1.96 TeV using 230 pb**{-1}
of data collected by the DO detector at the Fermilab Tevatron Collider. We
select events with one charged lepton (electron or muon), large missing
transverse energy, and at least four jets, and extract the ttbar content of the
sample based on the kinematic characteristics of the events. For a top quark
mass of 175 GeV, we measure sigma(ttbar) = 6.7 {+1.4-1.3} (stat) {+1.6- 1.1}
(syst) +/-0.4 (lumi) pb, in good agreement with the standard model prediction.Comment: submitted to Phys.Rev.Let
Measurement of the ttbar Production Cross Section in ppbar Collisions at sqrt(s)=1.96 TeV using Lepton + Jets Events with Lifetime b-tagging
We present a measurement of the top quark pair () production cross
section () in collisions at TeV
using 230 pb of data collected by the D0 experiment at the Fermilab
Tevatron Collider. We select events with one charged lepton (electron or muon),
missing transverse energy, and jets in the final state. We employ
lifetime-based b-jet identification techniques to further enhance the
purity of the selected sample. For a top quark mass of 175 GeV, we
measure pb, in
agreement with the standard model expectation.Comment: 7 pages, 2 figures, 3 tables Submitted to Phys.Rev.Let
Search for W' bosons decaying to an electron and a neutrino with the D0 detector
This Letter describes the search for a new heavy charged gauge boson W'
decaying into an electron and a neutrino. The data were collected with the D0
detector at the Fermilab Tevatron proton-antiproton Collider at a
center-of-mass energy of 1.96 TeV, and correspond to an integrated luminosity
of about 1 inverse femtobarn. Lacking any significant excess in the data in
comparison with known processes, an upper limit is set on the production cross
section times branching fraction, and a W' boson with mass below 1.00 TeV can
be excluded at the 95% C.L., assuming standard-model-like couplings to
fermions. This result significantly improves upon previous limits, and is the
most stringent to date.Comment: submitted to Phys. Rev. Let
Measurement of the ratios of the Z/G* + >= n jet production cross sections to the total inclusive Z/G* cross section in ppbar collisions at sqrt(s) = 1.96 TeV
We present a study of events with Z bosons and jets produced at the Fermilab
Tevatron Collider in ppbar collisions at a center of mass energy of 1.96 TeV.
The data sample consists of nearly 14,000 Z/G* -> e+e- candidates corresponding
to the integrated luminosity of 0.4 fb-1 collected using the D0 detector.
Ratios of the Z/G* + >= n jet cross sections to the total inclusive Z/G* cross
section have been measured for n = 1 to 4 jet events. Our measurements are
found to be in good agreement with a next-to-leading order QCD calculation and
with a tree-level QCD prediction with parton shower simulation and
hadronization.Comment: 7 pages, 2 figures, slightly modified, submitted to Phys. Lett.
Measurement of the Isolated Photon Cross Section in p-pbar Collisions at sqrt{s}=1.96 TeV
The cross section for the inclusive production of isolated photons has been
measured in p anti-p collisions at sqrt{s}=1.96 TeV with the D0 detector at the
Fermilab Tevatron Collider. The photons span transverse momenta 23 to 300 GeV
and have pseudorapidity |eta|<0.9. The cross section is compared with the
results from two next-to-leading order perturbative QCD calculations. The
theoretical predictions agree with the measurement within uncertainties.Comment: 7 pages, 5 figures, submitted to Phys.Lett.
Effects of watershed land use on nitrogen concentrations and δ15 Nitrogen in groundwater
Author Posting. © The Authors, 2005. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Biogeochemistry 77 (2006): 199-215, doi:10.1007/s10533-005-1036-2.Eutrophication is a major agent of change affecting freshwater, estuarine, and marine
systems. It is largely driven by transportation of nitrogen from natural and anthropogenic
sources. Research is needed to quantify this nitrogen delivery and to link the delivery to
specific land-derived sources. In this study we measured nitrogen concentrations and δ15N
values in seepage water entering three freshwater ponds and six estuaries on Cape Cod,
Massachusetts and assessed how they varied with different types of land use. Nitrate
concentrations and δ15N values in groundwater reflected land use in developed and pristine
watersheds. In particular, watersheds with larger populations delivered larger nitrate loads with
higher δ15N values to receiving waters. The enriched δ15N values confirmed nitrogen loading
model results identifying wastewater contributions from septic tanks as the major N source.
Furthermore, it was apparent that N coastal sources had a relatively larger impact on the N
loads and isotopic signatures than did inland N sources further upstream in the watersheds.
This finding suggests that management priorities could focus on coastal sources as a first
course of action. This would require management constraints on a much smaller population.This work was supported
by funds from the Woods Hole Oceanographic Institution Sea Grant Program, from the
Cooperative Institute for Coastal and Estuarine Environmental Technology, from
Massachusetts Department of Environmental Protection to Applied Science Associates,
Narragansett, RI, as well as from Palmer/McLeod and NOAA National Estuarine Research
Reserve Fellowships to Kevin Kroeger. This work is the result of research sponsored by NOAA
National Sea Grant College Program Office, Department of Commerce, under Grant No.
NA86RG0075, Woods Hole Oceanographic Institution Sea Grant Project No. R/M-40
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