9,746 research outputs found
Heavy Ion Collisions at the LHC; the ALICE Experiment
ALICE (A Large Ion Collider Experiment) is a detector designed to exploit the
physics potential of nucleus-nucleus interactions at the LHC. Being a general
purpose experiment, it will allow a comprehensive study of hadrons, electrons,
muons and photons, produced in the collision of heavy nuclei, up to the highest
particle multiplicities anticipated (dNch/dy=8000). In addition to heavy
systems (Pb-Pb), we will study collisions at smaller energy densities by using
lower-mass ions (e.g. A~40). Reference data will be obtained from pp and
p-nucleus collisions. The central part of ALICE covers , and
consists of an inner tracker (ITS), a TPC and a particle identification array
(PID), all embedded in a large magnet with a weak solenoidal field. The
experiment is completed by two small area spectrometers in the barrel region
(an electromagnetic calorimeter, PHOS, and a high momentum PID detector,
HMPID), a forward muon spectrometer (2 degrees to 9.5 degrees) and a ZDC.Comment: 6 pages, 3 figures, LaTeX, uses packages
graphicx,epsfig,amsmath,amssymb,cite,xspace,floa
In vitro reconstitution of Bluetongue virus infectious cores.
Bluetongue virus (BTV) is a vector-borne, nonenveloped icosahedral particle that is organized in two capsids, an outer capsid of two proteins, VP2 and VP5, and an inner capsid (or core) composed of two major proteins, VP7 and VP3, in two layers. The VP3 layer (subcore) encloses viral transcription complex (VP1 polymerase, VP4 capping enzyme, VP6 helicase) and a 10-segmented double-stranded (dsRNA) genome. Although much is known about the BTV capsids, the order of the core assembly and the mechanism of genome packaging remain unclear. Here, we established a cell-free system to reconstitute subcore and core structures with the proteins and ssRNAs, demonstrating that reconstituted cores are infectious in insect cells. Furthermore, we showed that the BTV ssRNAs are essential to drive the assembly reaction and that there is a distinct order of internal protein recruitment during the assembly process. The in vitro engineering of infectious BTV cores is unique for any member of the Reoviridae and will facilitate future studies of RNA-protein interactions during BTV core assembly
Some comments on particle image displacement velocimetry
Laser speckle velocimetry (LSV) or particle image displacement velocimetry, is introduced. This technique provides the simultaneous visualization of the two-dimensional streamline pattern in unsteady flows as well as the quantification of the velocity field over an entire plane. The advantage of this technique is that the velocity field can be measured over an entire plane of the flow field simultaneously, with accuracy and spatial resolution. From this the instantaneous vorticity field can be easily obtained. This constitutes a great asset for the study of a variety of flows that evolve stochastically in both space and time. The basic concept of LSV; methods of data acquisition and reduction, examples of its use, and parameters that affect its utilization are described
The introduction of new interventional procedures in the British National Health Service : A qualitative study
Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.Peer reviewedPostprin
Rotation-invariant relations in vector meson decays into fermion pairs
The rotational properties of angular momentum eigenstates imply the existence
of a frame-independent relation among the parameters of the decay distribution
of vector mesons into fermions. This relation is a generalization of the
Lam-Tung identity, a result specific to Drell-Yan production in perturbative
QCD, here shown to be equivalent to the dynamical condition that the dilepton
always originates from a transversely polarized photon
A new approach to quarkonium polarization studies
Significant progress in understanding quarkonium production requires improved
polarization measurements, fully considering the intrinsic multidimensionality
of the problem. We propose a frame-invariant formalism which minimizes the
dependence of the measured result on the experimental acceptance, facilitates
the comparison with theoretical calculations, and provides a much needed
control over systematic effects due to detector limitations and analysis
biases. This formalism is a direct and generic consequence of the rotational
invariance of the dilepton decay distribution and is independent of any
assumptions specific to particular models of quarkonium production
A Quantitative Analysis of Charmonium Suppression in Nuclear Collisions
Data from J/psi and psi' production in p-A collisions are used to determine
the cross section for absorption of pre-resonance charmonium in nuclear matter.
The J/psi suppression in O-Cu, O-U and S-U collisions is fully reproduced by
the corresponding nuclear absorption, while Pb-Pb collisions show an additional
suppression increasing with centrality. We study the onset of this change in
terms of hadronic comover interactions and conclude that so far no conventional
hadronic description can consistently account for all data. Deconfinement,
starting at a critical point determined by central S-U collisions, is in accord
with the observed suppression pattern.Comment: 37 pages, 12 figures, uses epsfig style, LaTe
Approaching stimuli bias attention in numerical space
Increasing evidence suggests that common mechanisms underlie the direction of attention in physical space and numerical space, along the mental number line. The small leftward bias (pseudoneglect) found on paper-and-pencil line bisection is also observed when participants âbisectâ number pairs, estimating (without calculating) the number midway between two others. Here we investigated the effect of stimulus motion on attention in numerical space. A two-frame apparent motion paradigm manipulating stimulus size was used to produce the impression that pairs of numbers were approaching (size increase from first to second frame), receding (size decrease), or not moving (no size change). The magnitude of pseudoneglect increased for approaching numbers, even when the final stimulus size was held constant. This result is consistent with previous findings that pseudoneglect in numerical space (as in physical space) increases as stimuli are brought closer to the participant. It also suggests that the perception of stimulus motion modulates attention over the mental number line and provides further support for a connection between the neural representations of physical space and number
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