4,723 research outputs found
Optimizing Observational Strategy for Future Fgas Constraints
The Planck cluster catalog is expected to contain of order a thousand galaxy
clusters, both newly discovered and previously known, detected through the
Sunyaev-Zeldovich effect over the redshift range 0 < z < 1. Follow-up X-ray
observations of a dynamically relaxed sub-sample of newly discovered Planck
clusters will improve constraints on the dark energy equation-of-state found
through measurement of the cluster gas mass fraction fgas. In view of follow-up
campaigns with XMM-Newton and Chandra, we determine the optimal redshift
distribution of a cluster sample to most tightly constrain the dark energy
equation of state. The distribution is non-trivial even for the standard w0-wa
parameterization. We then determine how much the combination of expected data
from the Planck satellite and fgas data will be able to constrain the dark
energy equation-of-state. Our analysis employs a Markov Chain Monte Carlo
method as well as a Fisher Matrix analysis. We find that these upcoming data
will be able to improve the figure-of-merit by at least a factor two.Comment: 11 pages, 8 figure
CTLA-4 rs231775 and risk of acute renal graft rejection: an updated meta-analysis with trial sequential analysis
Contrasting results exist on the association between CTLA-4 rs231775 and acute rejection in kidney transplant recipients. We herein conducted an updated systematic review with meta-analysis and trial sequential analysis (TSA) to clarify this relationship and to establish whether the current evidence is sufficient to draw firm conclusions. In addition, noteworthiness of significant pooled odds ratios (ORs) was estimated by false positive report probability (FPRP). A comprehensive search was performed through PubMed, Web of Knowledge, Cochrane Library and Open Grey up to October 2019. Fifteen independent cohorts, including a total of 5,401 kidney transplant recipients, were identified through the systematic review. Overall, no association was detected with the allelic (OR 1.07, 95% CI 0.88\u20131.30, P = 0.49), dominant (OR 0.94, 95% CI 0.73\u20131.22, P = 0.66) or the recessive (OR 1.18, 95% CI 0.97\u20131.43, P = 0.096) model of CTLA-4 rs231775. In each genetic model, the cumulative Z-curve in TSA crossed the futility boundary and entered the\ua0futility\ua0area. In addition, none of the significant genetic comparisons detected in the subsequent and sensitivity analyses or in previously reported meta-analyses were found to be noteworthy by FPRP. In conclusion, this study provides strong evidence that CTLA-4 rs231775 is not a clinically-relevant genetic risk determinant of acute rejection after renal transplantation
An Impacting Descent Probe for Europa and the other Galilean Moons of Jupiter
We present a study of an impacting descent probe that increases the science
return of spacecraft orbiting or passing an atmosphere-less planetary body of
the solar system, such as the Galilean moons of Jupiter. The descent probe is a
carry-on small spacecraft (< 100 kg), to be deployed by the mother spacecraft,
that brings itself onto a collisional trajectory with the targeted planetary
body in a simple manner. A possible science payload includes instruments for
surface imaging, characterisation of the neutral exosphere, and magnetic field
and plasma measurement near the target body down to very low-altitudes (~1 km),
during the probe's fast (~km/s) descent to the surface until impact. The
science goals and the concept of operation are discussed with particular
reference to Europa, including options for flying through water plumes and
after-impact retrieval of very-low altitude science data. All in all, it is
demonstrated how the descent probe has the potential to provide a high science
return to a mission at a low extra level of complexity, engineering effort, and
risk. This study builds upon earlier studies for a Callisto Descent Probe (CDP)
for the former Europa-Jupiter System Mission (EJSM) of ESA and NASA, and
extends them with a detailed assessment of a descent probe designed to be an
additional science payload for the NASA Europa Mission.Comment: 34 pages, 11 figure
Invariant mass line shape of B -> PP decays at LHCb
The family of B meson decays into pairs of charmless charged pseudo-scalar mesons comprises many different channels. In order to disentagle the overlapped mass peaks of the various decay modes, an accurate description of the invariant mass distribution of each mode is required. In particular, the invariant mass parameterization must take into account the effect of QED final state radiation, which leads to the presence of a long tail on the lower side of the mass peak. In this document we propose a new parameterization based on a complete QED calculation of the photon emission rate and we compare it to a simpler one based on phenomenological arguments. Furthermore, we show how the shape of the invariant mass distributions under the pi+pi- mass hypothesis, for every decay mode of interest, can be described very precisely by means of analytical calculations
Variational Monte Carlo study of the ground state properties and vacancy formation energy of solid para-H2 using a shadow wave function
A Shadow Wave Function (SWF) is employed along with Variational Monte Carlo
techniques to describe the ground state properties of solid molecular
para-hydrogen. The study has been extended to densities below the equilibrium
value, to obtain a parameterization of the SWF useful for the description of
inhomogeneous phases. We also present an estimate of the vacancy formation
energy as a function of the density, and discuss the importance of relaxation
effects near the vacant site
The Power Manager for the LHCb On-Line Farm
The Power Manager is a tool of the LHCb FMC (Farm Monitoring and Control System) which allows - in an OS-independent manner and without requiring expensive network-controlled power distributors - to switch the farm nodes on and off, and to monitor their physical condition: power status (on/off), temperatures, fan speeds and voltages. The Power Manager can operate on farm nodes whose motherboards and network interface cards implement the IPMI (Intelligent Platform Management Interface) specifications, version 1.5 or subsequent, and copes with several IPMI limitations
The Process Controller for the LHCb On-LIne Farm
The Process Controller is a tool of the LHCb FMC (Farm Monitoring and Control System) in charge of keeping a list of applications up and running on the farm nodes. It tipically runs on a few control PCs each one watching ~200 farm nodes and performs its task by maintaining the list of scheduled applications for each controlled farm node and by interacting with the Task Manager Servers running on the farm nodes to start processes, to obtain the notification of process termination, to re-spawn the terminated processes (if requested) and to stop processes. Processes can be added to or removed from the scheduled application list for one or more nodes by means of DIM commands, while DIM services provide the list of scheduled applications for each controlled farm node together with their properties, the number of re-spawns and the re-spawn times
Data transmission and selection for the L0 calorimeter trigger of LHCb
This report describes the optical transmitter boards and the Selection Crate, designed by the Bologna INFN-LHCb group, for the data transmission and the L0 calorimeter trigger of the LHCb experiment. The optical transmitters are used throughout the calorimeter system for data acquisition and the data transmission to the L0 trigger system. The optical transmitters allow transmitting 32 bit at the LHC clock of 40.08 MHz on a single fibre. The Selection Crate (SC) is used to select the most energetic deposits detected by the electromagnetic and the hadron calorimeters of LHCb, as well as to evaluate other auxiliary global trigger quantities (i.e. the total energy released and the hit multiplicity). The Selection Crate is a modular system equipped with homogeneous Selection Boards
Exponential decay properties of Wannier functions and related quantities
The spatial decay properties of Wannier functions and related quantities have
been investigated using analytical and numerical methods. We find that the form
of the decay is a power law times an exponential, with a particular power-law
exponent that is universal for each kind of quantity. In one dimension we find
an exponent of -3/4 for Wannier functions, -1/2 for the density matrix and for
energy matrix elements, and -1/2 or -3/2 for different constructions of
non-orthonormal Wannier-like functions.Comment: 4 pages, with 3 postscript figures embedded. Uses REVTEX and epsf
macros. Also available at
http://www.physics.rutgers.edu/~dhv/preprints/lh_wann/index.htm
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