4,380 research outputs found
Homological symbols and the Quillen conjecture
We formulate a "correct" version of the Quillen conjecture on linear group
homology for certain arithmetic rings and provide evidence for the new
conjecture. In this way we predict that the linear group homology has a direct
summand looking like an unstable form of Milnor K-theory and we call this new
theory "homological symbols algebra". As a byproduct we prove the Quillen
conjecture in homological degree two for the rank two and the prime 5
Detectability of CMB tensor B modes via delensing with weak lensing galaxy surveys
We analyze the possibility of delensing CMB polarization maps using
foreground weak lensing (WL) information. We build an estimator of the CMB
lensing potential out of optimally combined projected potential estimators to
different source redshift bins. Our estimator is most sensitive to the redshift
depth of the WL survey, less so to the shape noise level. Estimators built
using galaxy surveys like LSST and SNAP yield a 30-50% reduction in the lensing
B-mode power. We illustrate the potential advantages of a 21-cm survey by
considering a fiducial WL survey for which we take the redshift depth zmax and
the effective angular concentration of sources n as free parameters. For a
noise level of 1 muK arcmin in the polarization map itself, as projected for a
CMBPol experiment, and a beam with FWHM=10 arcmin, we find that going to
zmax=20 at n=100 gal/sqarcmin yields a delensing performance similar to that of
a quadratic lensing potential estimator applied to small-scale CMB maps: the
lensing B-mode contamination is reduced by almost an order of magnitude. In
this case, there is also a reduction by a factor of ~4 in the detectability
threshold of the tensor B-mode power. At this CMB noise level, there is little
gain from sources with zmax>20. The delensing gains are lost if the CMB beam
exceeds ~20 arcmin. The delensing efficiency and useful zmax depend acutely on
the CMB map noise level, but beam sizes below 10 arcmin do not help. Delensing
via foreground sources does not require arcminute-resolution CMB observations,
a substantial practical advantage over the use of CMB observables for
delensing.Comment: 10 pages, 5 figures; accepted for publication in Physical Review
Biglycan : a multivalent proteoglycan providing structure and signals
Research over the past few years has provided fascinating results indicating that biglycan, besides being a ubiquitous structural component of the extracellular matrix (ECM), may act as a signaling molecule. Proteolytically released from the ECM, biglycan acts as a danger signal signifying tissue stress or injury. As a ligand of innate immunity receptors and activator of the inflammasome, biglycan stimulates multifunctional proinflammatory signaling linking the innate to the adaptive immune response. By clustering several types of receptors on the cell surface and orchestrating their downstream signaling events, biglycan is capable to autonomously trigger sterile inflammation and to potentiate the inflammatory response to microbial invasion. Besides operating in a broad biological context, biglycan also displays tissue-specific affinities to certain receptors and structural components, thereby playing a crucial role in bone formation, muscle integrity, and synapse stability at the neuromuscular junction. This review attempts to provide a concise summary of recent data regarding the involvement of biglycan in the regulation of inflammation and the musculoskeletal system, pointing out both a signaling and a structural role for this proteoglycan. The potential of biglycan as a novel therapeutic target or agent for the treatment of inflammatory diseases and skeletal muscular dystrophies is also addressed
Saturation physics and angular correlations at RHIC and LHC
We investigate the angular correlation between pions and photons produced in
deuteron-gold collisions at RHIC and proton-lead collisions at LHC using the
Color Glass Condensate formalism and make predictions for the dependence of the
production cross section on the angle between the pion and photon at different
rapidities and transverse momenta. Measuring this dependence would shed further
light on the role of high gluon density and saturation dynamics at RHIC and
LHC.Comment: 2-column EPJ C format, requires svjour.cls and svepj.clo; 4 pages, 4
figure
Probing colored glass via photoproduction
In this paper, we calculate the cross-section for the photoproduction of
quark-antiquark pairs in the peripheral collision of ultra-relativistic nuclei,
by treating the color field of the nuclei within the Color Glass Condensate
model. We find that this cross-section is sensitive to the saturation scale
that characterizes the model. In particular, the transverse momentum
spectrum of the produced pairs could be used to measure the properties of the
color glass condensate.Comment: 25 pages LaTeX document - A reference and some footnotes added
(version to appear in Nucl. Phys. A
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