1,171 research outputs found
The Rules of Human T Cell Fate in vivo.
The processes governing lymphocyte fate (division, differentiation, and death), are typically assumed to be independent of cell age. This assumption has been challenged by a series of elegant studies which clearly show that, for murine cells in vitro, lymphocyte fate is age-dependent and that younger cells (i.e., cells which have recently divided) are less likely to divide or die. Here we investigate whether the same rules determine human T cell fate in vivo. We combined data from in vivo stable isotope labeling in healthy humans with stochastic, agent-based mathematical modeling. We show firstly that the choice of model paradigm has a large impact on parameter estimates obtained using stable isotope labeling i.e., different models fitted to the same data can yield very different estimates of T cell lifespan. Secondly, we found no evidence in humans in vivo to support the model in which younger T cells are less likely to divide or die. This age-dependent model never provided the best description of isotope labeling; this was true for naïve and memory, CD4+ and CD8+ T cells. Furthermore, this age-dependent model also failed to predict an independent data set in which the link between division and death was explored using Annexin V and deuterated glucose. In contrast, the age-independent model provided the best description of both naïve and memory T cell dynamics and was also able to predict the independent dataset
Overview of the CKM Matrix
The current status of the determination of the elements of the
Cabibbo-Kobayashi-Maskawa quark-mixing matrix is reviewed. Tensions in the
global fits are highlighted. Particular attention is paid to progress in, and
prospects for, measurements of CP violation effects.Comment: Proceedings of the Lepton Photon 2011 Conference, to appear in
"Pramana - journal of physics", 17 pages, 13 figure
Quantum-fluid dynamics of microcavity polaritons
Semiconductor microcavities offer a unique system to investigate the physics
of weakly interacting bosons. Their elementary excitations, polaritons--a
mixture of excitons and photons--behave, in the low density limit, as bosons
that can undergo a phase transition to a regime characterised by long range
coherence. Condensates of polaritons have been advocated as candidates for
superfluidity; and the formation of vortices as well as elementary excitations
with a linear dispersion are actively sought after. In this work, we have
created and set in motion a macroscopically degenerate state of polaritons and
let it collide with a variety of defects present in the sample. Our experiments
show striking manifestations of a coherent light-matter packet that displays
features of a superfluid, although one of a highly unusual character as it
involves an out-of-equilibrium dissipative system where it travels at
ultra-fast velocity of the order of 1% the speed of light. Our main results are
the observation of i) a linear polariton dispersion accompanied with
diffusion-less motion, ii) flow without resistance when crossing an obstacle,
iii) suppression of Rayleigh scattering and iv) splitting into two fluids when
the size of the obstacle is comparable with the size of the wavepacket. This
work opens the way to the investigation of new phenomenology of
out-of-equilibrium condensates.Comment: 22 pages, 5 figure
Migrant Health: Sexual transmission of HIV within migrant groups in the EU/EEA and implications for effective interventions
This report presents the published evidence of sexual transmission of HIV among populations from countries with
generalised HIV epidemics in the European Union/European Economic Area (EU/EEA). Member states’ surveillance
systems for monitoring the sexual transmission of HIV in the EU/EEA among migrant populations are also profiled.
The implications of this evidence are summarised and recommendations provided for those Member States that
wish to improve their surveillance systems in order to assess the sexual transmission of HIV in their at-risk migrant
populations. The evidence can also be used as a basis for policy and programmatic activities targeted toward
migrant populations
Two-loop Corrections to the B to pi Form Factor from QCD Sum Rules on the Light-Cone and |V(ub)|
We calculate the leading-twist O(alphas^2 beta0) corrections to the B to pi
transition form factor f+(0) in light-cone sum rules. We find that, as
expected, there is a cancellation between the O(alphas^2 beta0) corrections to
fB f+(0) and the large corresponding corrections to fB, calculated in QCD sum
rules. This suggests the insensitivity of the form factors calculated in the
light-cone sum rules approach to this source of radiative corrections. We
further obtain an improved determination of the CKM matrix element |V(ub)|,
using latest results from BaBar and Belle for f+(0)|V(ub)|.Comment: 18 pages, 3 figure
Cost-Utility Analysis of a Medication Review with Follow-Up Service for Older Adults with Polypharmacy in Community Pharmacies in Spain: The conSIGUE Program
© 2015, Springer International Publishing Switzerland. Background: The concept of pharmaceutical care is operationalized through pharmaceutical professional services, which are patient-oriented to optimize their pharmacotherapy and to improve clinical outcomes. Objective: The objective of this study was to estimate the incremental cost-effectiveness ratio (ICER) of a medication review with follow-up (MRF) service for older adults with polypharmacy in Spanish community pharmacies against the alternative of having their medication dispensed normally. Methods: The study was designed as a cluster randomized controlled trial, and was carried out over a time horizon of 6 months. The target population was older adults with polypharmacy, defined as individuals taking five or more medicines per day. The study was conducted in 178 community pharmacies in Spain. Cost-utility analysis adopted a health service perspective. Costs were in euros at 2014 prices and the effectiveness of the intervention was estimated as quality-adjusted life-years (QALYs). In order to analyze the uncertainty of ICER results, we performed a non-parametric bootstrapping with 5000 replications. Results: A total of 1403 older adults, aged between 65 and 94 years, were enrolled in the study: 688 in the intervention group (IG) and 715 in the control group (CG). By the end of the follow-up, both groups had reduced the mean number of prescribed medications they took, although this reduction was greater in the IG (0.28 ± 1.25 drugs; p < 0.001) than in the CG (0.07 ± 0.95 drugs; p = 0.063). Older adults in the IG saw their quality of life improved by 0.0528 ± 0.20 (p < 0.001). In contrast, the CG experienced a slight reduction in their quality of life: 0.0022 ± 0.24 (p = 0.815). The mean total cost was €977.57 ± 1455.88 for the IG and €1173.44 ± 3671.65 for the CG. In order to estimate the ICER, we used the costs adjusted for baseline medications and QALYs adjusted for baseline utility score, resulting in a mean incremental total cost of −€250.51 ± 148.61 (95 % CI −541.79 to 40.76) and a mean incremental QALY of 0.0156 ± 0.004 (95 % CI 0.008–0.023). Regarding the results from the cost-utility analysis, the MRF service emerged as the dominant strategy. Conclusion: The MRF service is an effective intervention for optimizing prescribed medication and improving quality of life in older adults with polypharmacy in community pharmacies. The results from the cost-utility analysis suggest that the MRF service is cost effective
B-> D* zero-recoil formfactor and the heavy quark expansion in QCD: a systematic study
We present a QCD analysis of heavy quark mesons focussing on the B -> D*
formfactor at zero recoil, F_D*(1). An advanced treatment of the perturbative
corrections in the Wilsonian approach is presented. We estimate the
higher-order power corrections to the OPE sum rule and describe a refined
analysis of the nonresonant continuum contribution. In the framework of a
model-independent approach, we show that the inelastic contribution in the
phenomenological part of the OPE is related to the mQ-dependence of the
hyperfine splitting and conclude that the former is large, lowering the
prediction for F_D*(1) down to about 0.86. This likewise implies an enhanced
yield of radial and D-wave charm excitations in semileptonic B decays and
alleviates the problem with the inclusive yield of the wide excited states. We
also apply the approach to the expectation values of dimension 7 and 8 local
operators and to a few other issues in the heavy quark expansion.Comment: 70 pages, 13 figure
The UTfit Collaboration Average of D meson mixing data: Spring 2012
We derive constraints on the parameters , and
that describe meson mixing using all available data, allowing
for CP violation. We also provide posterior distributions and predictions for
observable parameters appearing in physics.Comment: 5 pages, 3 figure
The LBNO long-baseline oscillation sensitivities with two conventional neutrino beams at different baselines
The proposed Long Baseline Neutrino Observatory (LBNO) initially consists of
kton liquid double phase TPC complemented by a magnetised iron
calorimeter, to be installed at the Pyh\"asalmi mine, at a distance of 2300 km
from CERN. The conventional neutrino beam is produced by 400 GeV protons
accelerated at the SPS accelerator delivering 700 kW of power. The long
baseline provides a unique opportunity to study neutrino flavour oscillations
over their 1st and 2nd oscillation maxima exploring the behaviour, and
distinguishing effects arising from and matter. In this paper we
show how this comprehensive physics case can be further enhanced and
complemented if a neutrino beam produced at the Protvino IHEP accelerator
complex, at a distance of 1160 km, and with modest power of 450 kW is aimed
towards the same far detectors. We show that the coupling of two independent
sub-MW conventional neutrino and antineutrino beams at different baselines from
CERN and Protvino will allow to measure CP violation in the leptonic sector at
a confidence level of at least for 50\% of the true values of
with a 20 kton detector. With a far detector of 70 kton, the
combination allows a sensitivity for 75\% of the true values of
after 10 years of running. Running two independent neutrino
beams, each at a power below 1 MW, is more within today's state of the art than
the long-term operation of a new single high-energy multi-MW facility, which
has several technical challenges and will likely require a learning curve.Comment: 21 pages, 12 figure
Determination of the muon charge sign with the dipolar spectrometers of the OPERA experiment
The OPERA long-baseline neutrino-oscillation experiment has observed the
direct appearance of in the CNGS beam. Two large muon
magnetic spectrometers are used to identify muons produced in the
leptonic decay and in interactions by measuring their charge and
momentum. Besides the kinematic analysis of the decays, background
resulting from the decay of charmed particles produced in
interactions is reduced by efficiently identifying the muon track. A new method
for the charge sign determination has been applied, via a weighted angular
matching of the straight track-segments reconstructed in the different parts of
the dipole magnets. Results obtained for Monte Carlo and real data are
presented. Comparison with a method where no matching is used shows a
significant reduction of up to 40\% of the fraction of wrongly determined
charges.Comment: 10 pages. Improvements in the tex
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