948 research outputs found
Accounting for the foreground contribution to the dust emission towards Kepler's supernova remnant
âThe definitive version is available at www3.interscience.wiley.com '. Copyright Royal Astronomical Society. DOI: 10.1111/j.1365-2966.2009.15061.xWhether or not supernovae contribute significantly to the overall dust budget is a controversial subject. Submillimetre (sub-mm) observations, sensitive to cold dust, have shown an excess at 450 and 850 ÎŒm in young remnants Cassiopeia A (Cas A) and Kepler. Some of the sub-mm emission from Cas A has been shown to be contaminated by unrelated material along the line of sight. In this paper, we explore the emission from material towards Kepler using sub-mm continuum imaging and spectroscopic observations of atomic and molecular gas, via H i, 12CO(J= 2â1) and 13CO(J= 2â1). We detect weak CO emission (peak T*A = 0.2â1 K, 1â2 km sâ1 full width at half-maximum) from diffuse, optically thin gas at the locations of some of the sub-mm clumps. The contribution to the sub-mm emission from foreground molecular and atomic clouds is negligible. The revised dust mass for Kepler's remnant is 0.1â1.2 Mâ , about half of the quoted values in the original study by Morgan et al., but still sufficient to explain the origin of dust at high redshifts.Peer reviewe
Step-by-step Guideline for disease-specific costing studies in low and middle income countries: a mixed methodology.
__Abstract__
BACKGROUND: Disease-specific costing studies can be used as input into cost-effectiveness analyses and provide important information for efficient resource allocation. However, limited data availability and limited expertise constrain such studies in low- and middle-income countries (LMICs).
OBJECTIVE: To describe a step-by-step guideline for conducting disease-specific costing studies in LMICs where data availability is limited and to illustrate how the guideline was applied in a costing study of cardiovascular disease prevention care in rural Nigeria.
DESIGN: The step-by-step guideline provides practical recommendations on methods and data requirements for six sequential steps: 1) definition of the study perspective, 2) characterization of the unit of analysis, 3) identification of cost items, 4) measurement of cost items, 5) valuation of cost items, and 6) uncertainty analyses.Please provide the significance of asterisk given in table body.
RESULTS: We discuss the necessary tradeoffs between the accuracy of estimates and data availability constraints at each step and illustrate how a mixed methodology of accurate bottom-up micro-costing and more feasible approaches can be used to make optimal use of all available data. An illustrative example from Nigeria is provided.
CONCLUSIONS: An innovative, user-friendly guideline for disease-specific costing in LMICs is presented, using a mixed methodology to account for limited data availability. The illustrative example showed that the step-by-step guideline can be used by healthcare professionals in LMICs to conduct feasible and accurate disease-specific cost analyses
From microscopic to macroscopic descriptions of cell\ud migration on growing domains
Cell migration and growth are essential components of the development of multicellular organisms. The role of various cues in directing cell migration is widespread, in particular, the role of signals in the environment in the control of cell motility and directional guidance. In many cases, especially in developmental biology, growth of the domain also plays a large role in the distribution of cells and, in some cases, cell or signal distribution may actually drive domain growth. There is a ubiquitous use of partial differential equations (PDEs) for modelling the time evolution of cellular density and environmental cues. In the last twenty years, a lot of attention has been devoted to connecting macroscopic PDEs with more detailed microscopic models of cellular motility, including models of directional sensing and signal transduction pathways. However, domain growth is largely omitted in the literature. In this paper, individual-based models describing cell movement and domain growth are studied, and correspondence with a macroscopic-level PDE describing the evolution of cell density is demonstrated. The individual-based models are formulated in terms of random walkers on a lattice. Domain growth provides an extra mathematical challenge by making the lattice size variable over time. A reaction-diffusion master equation formalism is generalised to the case of growing lattices and used in the derivation of the macroscopic PDEs
Prediction of Neutrino Fluxes in the NOMAD Experiment
The method developed for the calculation of the flux and composition of the
West Area Neutrino Beam used by NOMAD in its search for neutrino oscillations
is described. The calculation is based on particle production rates computed
using a recent version of FLUKA and modified to take into account the cross
sections measured by the SPY and NA20 experiments. These particles are
propagated through the beam line taking into account the material and magnetic
fields they traverse. The neutrinos produced through their decays are tracked
to the NOMAD detector. The fluxes of the four neutrino flavours at NOMAD are
predicted with an uncertainty of about 8% for nu(mu) and nu(e), 10% for
antinu(mu), and 12% for antinu(e). The energy-dependent uncertainty achieved on
the R(e, mu) prediction needed for a nu(mu)->nu(e) oscillation search ranges
from 4% to 7%, whereas the overall normalization uncertainty on this ratio is
4.2%.Comment: 43 pages, 20 figures. Submitted to Nucl. Phys.
A Study of Strange Particles Produced in Neutrino Neutral Current Interactions in the NOMAD Experiment
Results of a detailed study of strange particle production in neutrino
neutral current interactions are presented using the data from the NOMAD
experiment. Integral yields of neutral strange particles (K0s, Lambda,
Lambda-bar) have been measured. Decays of resonances and heavy hyperons with an
identified K0s or Lambda in the final state have been analyzed. Clear signals
corresponding to K* and Sigma(1385) have been observed. First results on the
measurements of the Lambda polarization in neutral current interactions have
been obtained.Comment: Accepted for publication in Nuclear Physics B as a rapid
communicatio
Measurement of the branching fraction
The branching fraction is measured in a data sample
corresponding to 0.41 of integrated luminosity collected with the LHCb
detector at the LHC. This channel is sensitive to the penguin contributions
affecting the sin2 measurement from The
time-integrated branching fraction is measured to be . This is the most precise measurement to
date
Measurement of the CP-violating phase \phi s in Bs->J/\psi\pi+\pi- decays
Measurement of the mixing-induced CP-violating phase phi_s in Bs decays is of
prime importance in probing new physics. Here 7421 +/- 105 signal events from
the dominantly CP-odd final state J/\psi pi+ pi- are selected in 1/fb of pp
collision data collected at sqrt{s} = 7 TeV with the LHCb detector. A
time-dependent fit to the data yields a value of
phi_s=-0.019^{+0.173+0.004}_{-0.174-0.003} rad, consistent with the Standard
Model expectation. No evidence of direct CP violation is found.Comment: 15 pages, 10 figures; minor revisions on May 23, 201
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
Search for the lepton-flavor-violating decays Bs0âe±Όâ and B0âe±Όâ
A search for the lepton-flavor-violating decays Bs0âe±Όâ and B0âe±Όâ is performed with a data sample, corresponding to an integrated luminosity of 1.0ââfb-1 of pp collisions at âs=7ââTeV, collected by the LHCb experiment. The observed number of Bs0âe±Όâ and B0âe±Όâ candidates is consistent with background expectations. Upper limits on the branching fractions of both decays are determined to be B(Bs0âe±Όâ)101ââTeV/c2 and MLQ(B0âe±Όâ)>126ââTeV/c2 at 95% C.L., and are a factor of 2 higher than the previous bounds
- âŠ