1,004 research outputs found
Early postoperative risk stratification in patients with pancreatic fistula after pancreaticoduodenectomy
Background: Early stratification of postoperative pancreatic fistula according to severity and/or need for invasive intervention may improve outcomes after pancreaticoduodenectomy. This study aimed to identify the early postoperative variables that may predict postoperative pancreatic fistula severity.Methods: All patients diagnosed with biochemical leak and clinically relevant-postoperative pancreatic fistula based on drain fluid amylase >300 U/L on the fifth postoperative day after pancreaticoduodenectomy were identified from a consecutive cohort from Birmingham, UK. Demographics, intraoperative parameters, and postoperative laboratory results on postoperative days 1 through 7 were retrospectively extracted. Independent predictors of clinically relevant-postoperative pancreatic fistula were identified using multivariable binary logistic regression and converted into a risk score, which was applied to an external cohort from Verona, Italy. Results: The Birmingham cohort had 187 patients diagnosed with postoperative pancreatic fistula (biochemical leak: 99, clinically relevant: 88). In clinically relevant-postoperative pancreatic fistula pa-tients, the leak became clinically relevant at a median of 9 days (interquartile range: 6-13) after pan-creaticoduodenectomy. Male sex (P = .002), drain fluid amylase-postoperative day 3 (P < .001), c-reactive protein postoperative day 3 (P < .001), and albumin-postoperative day 3 (P = .028) were found to be sig-nificant predictors of clinically relevant-postoperative pancreatic fistula on multivariable analysis. The multivariable model was converted into a risk score with an area under the receiver operating characteristic curve of 0.78 (standard error: 0.038). This score significantly predicted the need for invasive intervention (postoperative pancreatic fistula grades B3 and C) in the Verona cohort (n = 121; area under the receiver operating characteristic curve: 0.68; standard error = 0.06; P =.006) but did not predict clinically relevant -postoperative pancreatic fistula when grades B1 and B2 were included (area under the receiver operating characteristic curve 0.52; standard error = 0.07; P = .802). Conclusion: We developed a novel risk score based on early postoperative laboratory values that can accurately predict higher grades of clinically relevant-postoperative pancreatic fistula requiring invasive intervention. Early identification of severe postoperative pancreatic fistula may allow earlier intervention. Crown Copyright (c) 2022 Published by Elsevier Inc. All rights reserved
Search for CP violation in D+âÏÏ+ and D+sâK0SÏ+ decays
A search for CP violation in D + â ÏÏ + decays is performed using data collected in 2011 by the LHCb experiment corresponding to an integrated luminosity of 1.0 fbâ1 at a centre of mass energy of 7 TeV. The CP -violating asymmetry is measured to be (â0.04 ± 0.14 ± 0.14)% for candidates with K â K + mass within 20 MeV/c 2 of the Ï meson mass. A search for a CP -violating asymmetry that varies across the Ï mass region of the D + â K â K + Ï + Dalitz plot is also performed, and no evidence for CP violation is found. In addition, the CP asymmetry in the D+sâK0SÏ+ decay is measured to be (0.61 ± 0.83 ± 0.14)%
Differential branching fraction and angular analysis of the decay B0âKâ0ÎŒ+ÎŒâ
The angular distribution and differential branching fraction of the decay B 0â K â0 ÎŒ + ÎŒ â are studied using a data sample, collected by the LHCb experiment in pp collisions at sâ=7 TeV, corresponding to an integrated luminosity of 1.0 fbâ1. Several angular observables are measured in bins of the dimuon invariant mass squared, q 2. A first measurement of the zero-crossing point of the forward-backward asymmetry of the dimuon system is also presented. The zero-crossing point is measured to be q20=4.9±0.9GeV2/c4 , where the uncertainty is the sum of statistical and systematic uncertainties. The results are consistent with the Standard Model predictions
Observation of associated production of a boson with a meson in the~forward region
A search for associated production of a boson with an open charm meson is
presented using a data sample, corresponding to an integrated luminosity of
of proton--proton collisions at a centre-of-mass energy
of 7\,TeV, collected by the LHCb experiment. %% Seven candidate events for
associated production of a boson with a meson and four candidate
events for a boson with a meson are observed with a combined
significance of 5.1standard deviations. The production cross-sections in the
forward region are measured to be where the first uncertainty is statistical and the
second systematic.Comment: 18 pages, 2 figure
Search for CP violation in decays
A model-independent search for direct CP violation in the Cabibbo suppressed
decay in a sample of approximately 370,000 decays is
carried out. The data were collected by the LHCb experiment in 2010 and
correspond to an integrated luminosity of 35 pb. The normalized Dalitz
plot distributions for and are compared using four different
binning schemes that are sensitive to different manifestations of CP violation.
No evidence for CP asymmetry is found.Comment: 13 pages, 8 figures, submitted to Phys. Rev.
Measurement of the CKM angle Îł from a combination of B±âDh± analyses
A combination of three LHCb measurements of the CKM angle Îł is presented. The decays B±âD K± and
B±âDϱ are used, where D denotes an admixture of D0 and D0 mesons, decaying into K+Kâ, Ï+Ïâ, K±Ïâ, K±ÏâϱÏâ, K0SÏ+Ïâ, or K0S K+Kâ ïŹnal states. All measurements use a dataset corresponding to 1.0 fbâ1 of integrated luminosity. Combining results from B±âD K± decays alone a best-ïŹt value of
Îł =72.0⊠is found, and conïŹdence intervals are set
Îł â [56.4,86.7]⊠at 68% CL,
Îł â [42.6,99.6]⊠at 95% CL.
The best-ïŹt value of Îł found from a combination of results from B±âDϱ decays alone, is Îł =18.9âŠ,
and the conïŹdence intervals
Îł â [7.4,99.2]⊠âȘ [167.9,176.4]⊠at 68% CL
are set, without constraint at 95% CL. The combination of results from B± â D K± and B± â Dϱ
decays gives a best-ïŹt value of Îł =72.6⊠and the conïŹdence intervals
Îł â [55.4,82.3]⊠at 68% CL,
Îł â [40.2,92.7]⊠at 95% CL
are set. All values are expressed modulo 180âŠ, and are obtained taking into account the effect of D0âD0
mixing
Measurements of the , , meson and baryon lifetimes
Measurements of -hadron lifetimes are reported using collision data,
corresponding to an integrated luminosity of 1.0fb, collected by the
LHCb detector at a centre-of-mass energy of Tev. Using the exclusive decays
, , ,
and the average decay
times in these modes are measured to be = 0.004 0.003 ps, =
0.006 0.004 ps, = 0.013
0.005 ps, = 0.027
0.006 ps and = 0.011
0.005 ps, where the first uncertainty is statistical and the second is
systematic. These represent the most precise lifetime measurements in these
decay modes. In addition, ratios of these lifetimes, and the ratio of the
decay-width difference, , to the average width, , in
the system, , are
reported. All quantities are found to be consistent with Standard Model
expectations.Comment: 28 pages, 4 figures. Updated reference
Measurement of the relative rate of prompt Ïc0, Ïc1 and Ïc2 production at âs=7TeV
Prompt production of charmonium Ïc0, Ïc1 and Ïc2 mesons is studied using proton-proton collisions at the LHC at a centre-of-mass energy of âs=7TeV. The Ïc mesons are identified through their decay to J/ÏÎł, with J/ÏâÎŒ+muâ using photons that converted in the detector. A data sample, corresponding to an integrated luminosity of 1.0fbâ1 collected by the LHCb detector, is used to measure the relative prompt production rate of Ïc1 and Ïc2 in the rapidity range 2.0<y<4.5 as a function of the J/Ï transverse momentum from 3 to 20 GeV/c. First evidence for Ïc0 meson production at a hadron collider is also presented
Model-independent search for CP violation in D0âKâK+ÏâÏ+ and D0âÏâÏ+Ï+Ïâ decays
A search for CP violation in the phase-space structures of D0 and View the MathML source decays to the final states KâK+ÏâÏ+ and ÏâÏ+Ï+Ïâ is presented. The search is carried out with a data set corresponding to an integrated luminosity of 1.0 fbâ1 collected in 2011 by the LHCb experiment in pp collisions at a centre-of-mass energy of 7 TeV. For the KâK+ÏâÏ+ final state, the four-body phase space is divided into 32 bins, each bin with approximately 1800 decays. The p-value under the hypothesis of no CP violation is 9.1%, and in no bin is a CP asymmetry greater than 6.5% observed. The phase space of the ÏâÏ+Ï+Ïâ final state is partitioned into 128 bins, each bin with approximately 2500 decays. The p-value under the hypothesis of no CP violation is 41%, and in no bin is a CP asymmetry greater than 5.5% observed. All results are consistent with the hypothesis of no CP violation at the current sensitivity
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