627 research outputs found
Interferometric detection of a single vortex in a dilute Bose-Einstein condensate
Using two radio frequency pulses separated in time we perform an amplitude
division interference experiment on a rubidium Bose-Einstein condensate. The
presence of a quantized vortex, which is nucleated by stirring the condensate
with a laser beam, is revealed by a dislocation in the fringe pattern.Comment: 4 pages, 4 figure
Testing quantum correlations in a confined atomic cloud by scattering fast atoms
We suggest measuring one-particle density matrix of a trapped ultracold
atomic cloud by scattering fast atoms in a pure momentum state off the cloud.
The lowest-order probability of the inelastic process, resulting in a pair of
outcoming fast atoms for each incoming one, turns out to be given by a Fourier
transform of the density matrix. Accordingly, important information about
quantum correlations can be deduced directly from the differential scattering
cross-section. A possible design of the atomic detector is also discussed.Comment: 5 RevTex pages, no figures, submitted to PR
Quantifying the impact of variability in railway bridge asset management
Bridge asset management is often a challenging and complicated task due to the diversity, multitude and variation of bridge configurations. Much research has been carried out in the field of asset management which has resulted in a wealth of models to help with the decision making process. However, often these models oversimplify the process, resulting in a decision making tool that trivialises the complexity of the decisions. The purpose of this study was to ascertain what the main sources of variability are in the process and then quantify the impact of them in terms of the Whole Life-Cycle Cost (WLCC). The study focuses on human-induced variability to ensure the results are directly influenceable by bridge portfolio managers. The sources of variability identified include misdiagnoses of defects as well as imperfect repairs and variability in costs, all of which are aspects that bridge portfolio managers are exposed to. The sources of variability are quantified and then incorporated into an existing railway bridge WLCC model, established in a previous study, which uses a flexible Petri-Net (PN) approach which is able to incorporate the complex logic and probabilistic aspects. The model itself is able to replicate some of the more complicated decisions which have to be made in bridge asset management, especially those which influence the decisions around rehabilitation. The resulting model, enhanced with the probabilistic variability, is able to reveal the impact of variability on the asset condition, WLCC and even understand where operational complexities are occurring within the system. Incorporating human-induced variability into any model will inevitably increase the financial and operational burden predicted by the model, however, recognising and modelling these aspects is a crucial step in providing bridge portfolio managers a more robust and accurate decision making tool which can more accurately replicate the real world system
-minimal surface and manifold with positive -Bakry-\'{E}mery Ricci curvature
In this paper, we first prove a compactness theorem for the space of closed
embedded -minimal surfaces of fixed topology in a closed three-manifold with
positive Bakry-\'{E}mery Ricci curvature. Then we give a Lichnerowicz type
lower bound of the first eigenvalue of the -Laplacian on compact manifold
with positive -Bakry-\'{E}mery Ricci curvature, and prove that the lower
bound is achieved only if the manifold is isometric to the -shpere, or the
-dimensional hemisphere. Finally, for compact manifold with positive
-Bakry-\'{E}mery Ricci curvature and -mean convex boundary, we prove an
upper bound for the distance function to the boundary, and the upper bound is
achieved if only if the manifold is isometric to an Euclidean ball.Comment: 15 page
Application of Pulsed Field Gel Electrophoresis to Determine Îł-ray-induced Double-strand Breaks in Yeast Chromosomal Molecules
The frequency of DNA double-strand breaks (dsb) was determined in yeast cells exposed to Îł-rays under anoxic conditions. Genomic DNA of treated cells was separated by pulsed field gel electrophoresis, and two different approaches for the evaluation of the gels were employed: (1) The DNA mass distribution profile obtained by electrophoresis was compared to computed profiles, and the number of DSB per unit length was then derived in terms of a fitting procedure; (2) hybridization of selected chromosomes was performed, and a comparison of the hybridization signals in treated and untreated samples was then used to derive the frequency of dsb
National predictors of influenza vaccine uptake in pregnancy: the FluMum prospective cohort study, Australia, 2012â2015
Objective: Ascertain predictors of inactivated influenza vaccine (IIV) uptake in pregnancy in motherâinfant pairs from six Australian sites over four consecutive influenza seasons (2012â2015). Methods: Prospective observational cohort study calculating proportions of unvaccinated and vaccinated pregnancies. Multivariable logistic regression calculating adjusted odds ratios (aOR) and 95% confidence intervals (95%CI) to determine demographic, pregnancy and birth characteristics as predictors of IIV uptake in pregnancy. Results: Uptake of IIV was 36% (n=3,651/9,878) with only 3â4% during the first trimester. Validation of IIV receipt was obtained for 77% of vaccinated participants. Predictors of IIV uptake in pregnancy were: healthcare provider recommendation to have IIV during pregnancy (aOR 7.04 [95%CI 5.83-8.50]): GP (aOR 4.12 [95%CI 3.43-4.98]), obstetrician (aOR 4.41 [95%CI 3.45-5.64]), midwife (aOR 1.88 [95%CI 1.51-2.36]); previous IIV within 12 months of their current pregnancy (aOR 2.87 [95%CI 2.36-3.50]); and pertussis vaccination during the current pregnancy (aOR 4.88 [95%CI 4.08-5.83]). Conclusions and implications for public health: Healthcare provider discussions with pregnant women about the risks associated with influenza infection during pregnancy and early infancy and evidence about the safety and effectiveness of IIV are required. Recommending and offering IIV in pregnancy needs to be included in these discussions to improve uptake.Lisa McHugh, Kerry-Ann F. OâGrady, Terry Nolan, Peter C. Richmond, Nicholas Wood, Helen S. Marshall, Stephen B. Lambert, Mark D. Chatfield, Kirsten P. Perrett, Paula Binks, Michael J. Binks, Ross M. Andrew
Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV
Results are presented from a search for a W' boson using a dataset
corresponding to 5.0 inverse femtobarns of integrated luminosity collected
during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV.
The W' boson is modeled as a heavy W boson, but different scenarios for the
couplings to fermions are considered, involving both left-handed and
right-handed chiral projections of the fermions, as well as an arbitrary
mixture of the two. The search is performed in the decay channel W' to t b,
leading to a final state signature with a single lepton (e, mu), missing
transverse energy, and jets, at least one of which is tagged as a b-jet. A W'
boson that couples to fermions with the same coupling constant as the W, but to
the right-handed rather than left-handed chiral projections, is excluded for
masses below 1.85 TeV at the 95% confidence level. For the first time using LHC
data, constraints on the W' gauge coupling for a set of left- and right-handed
coupling combinations have been placed. These results represent a significant
improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe
Search for the standard model Higgs boson decaying into two photons in pp collisions at sqrt(s)=7 TeV
A search for a Higgs boson decaying into two photons is described. The
analysis is performed using a dataset recorded by the CMS experiment at the LHC
from pp collisions at a centre-of-mass energy of 7 TeV, which corresponds to an
integrated luminosity of 4.8 inverse femtobarns. Limits are set on the cross
section of the standard model Higgs boson decaying to two photons. The expected
exclusion limit at 95% confidence level is between 1.4 and 2.4 times the
standard model cross section in the mass range between 110 and 150 GeV. The
analysis of the data excludes, at 95% confidence level, the standard model
Higgs boson decaying into two photons in the mass range 128 to 132 GeV. The
largest excess of events above the expected standard model background is
observed for a Higgs boson mass hypothesis of 124 GeV with a local significance
of 3.1 sigma. The global significance of observing an excess with a local
significance greater than 3.1 sigma anywhere in the search range 110-150 GeV is
estimated to be 1.8 sigma. More data are required to ascertain the origin of
this excess.Comment: Submitted to Physics Letters
Measurement of the Lambda(b) cross section and the anti-Lambda(b) to Lambda(b) ratio with Lambda(b) to J/Psi Lambda decays in pp collisions at sqrt(s) = 7 TeV
The Lambda(b) differential production cross section and the cross section
ratio anti-Lambda(b)/Lambda(b) are measured as functions of transverse momentum
pt(Lambda(b)) and rapidity abs(y(Lambda(b))) in pp collisions at sqrt(s) = 7
TeV using data collected by the CMS experiment at the LHC. The measurements are
based on Lambda(b) decays reconstructed in the exclusive final state J/Psi
Lambda, with the subsequent decays J/Psi to an opposite-sign muon pair and
Lambda to proton pion, using a data sample corresponding to an integrated
luminosity of 1.9 inverse femtobarns. The product of the cross section times
the branching ratio for Lambda(b) to J/Psi Lambda versus pt(Lambda(b)) falls
faster than that of b mesons. The measured value of the cross section times the
branching ratio for pt(Lambda(b)) > 10 GeV and abs(y(Lambda(b))) < 2.0 is 1.06
+/- 0.06 +/- 0.12 nb, and the integrated cross section ratio for
anti-Lambda(b)/Lambda(b) is 1.02 +/- 0.07 +/- 0.09, where the uncertainties are
statistical and systematic, respectively.Comment: Submitted to Physics Letters
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