13,377 research outputs found
Recognizing nullhomotopic maps into the classifying space of a Kac-Moody group
This paper extends certain characterizations of nullhomotopic maps between
p-compact groups to maps with target the p-completed classifying space of a
connected Kac-Moody group and source the classifying space of either a
p-compact group or a connected Kac-Moody group. A well known inductive
principle for p-compact groups is applied to obtain general, mapping space
level results. An arithmetic fiber square computation shows that a null map
from the classifying space of a connected compact Lie group to the classifying
space of a connected topological Kac-Moody group can be detected by restricting
to the maximal torus. Null maps between the classifying spaces of connected
topological Kac-Moody groups cannot, in general, be detected by restricting to
the maximal torus due to the nonvanishing of an explicit abelian group of
obstructions described here. Nevertheless, partial results are obtained via the
application of algebraic discrete Morse theory to higher derived limit
calculations which show that such detection is possible in many cases of
interest.Comment: References added, minor corrections; 29 pages, 4 figures, one tabl
Raster graphics extensions to the core system
A conceptual model of raster graphics systems was developed. The model integrates core-like graphics package concepts with contemporary raster display architectures. The conceptual model of raster graphics introduces multiple pixel matrices with associated index tables
Large deviations of a modified Jackson network: stability and rough asymptotics
Consider a modified, stable, two node Jackson network where server 2 helps
server 1 when server 2 is idle. The probability of a large deviation of the
number of customers at node one can be calculated using the flat boundary
theory of Schwartz and Weiss [Large Deviations Performance Analysis (1994),
Chapman and Hall, New York]. Surprisingly, however, these calculations show
that the proportion of time spent on the boundary, where server 2 is idle, may
be zero. This is in sharp contrast to the unmodified Jackson network which
spends a nonzero proportion of time on this boundary.Comment: Published at http://dx.doi.org/10.1214/105051604000000666 in the
Annals of Applied Probability (http://www.imstat.org/aap/) by the Institute
of Mathematical Statistics (http://www.imstat.org
Research into fundamental phenomena associated with spacecraft electrochemical devices - Calorimetry of nickel-cadmium cells Progress report, 1 Jul. - 30 Sep. 1968
Training of electrochemist in battery research and collecting electrochemical and thermodynamic dat
ICL: The Image Composition Language
The Image Composition Language (ICL) provides a convenient way for programmers of interactive graphics application programs to define how the video look-up table of a raster display system is to be loaded. The ICL allows one or several images stored in the frame buffer to be combined in a variety of ways. The ICL treats these images as variables, and provides arithematic, relational, and conditional operators to combine the images, scalar variables, and constants in image composition expressions. The objective of ICL is to provide programmers with a simple way to compose images, to relieve the tedium usually associated with loading the video look-up table to obtain desired results
Discovery and Cosmological Implications of SPT-CL J2106-5844, the Most Massive Known Cluster at z>1
Using the South Pole Telescope (SPT), we have discovered the most massive known galaxy cluster at z>1, SPT-CL J2106-5844. In addition to producing a strong Sunyaev-Zel'dovich (SZ) effect signal, this system is a luminous X-ray source and its numerous constituent galaxies display spatial and color clustering, all indicating the presence of a massive galaxy cluster. Very Large Telescope and Magellan spectroscopy of 18 member galaxies shows that the cluster is at z = 1.132^(+0.002)_(–0.003). Chandra observations obtained through a combined HRC-ACIS GTO program reveal an X-ray spectrum with an Fe K line redshifted by z = 1.18 ± 0.03. These redshifts are consistent with the galaxy colors found in optical, near-infrared, and mid-infrared imaging. SPT-CL J2106-5844 displays extreme X-ray properties for a cluster having a core-excluded temperature of T_X = 11.0^(+2.6)_(–1.9) keV and a luminosity (within r _(500)) of LX (0.5-2.0 keV) = (13.9 ± 1.0) × 10_(44) erg s^(–1). The combined mass estimate from measurements of the SZ effect and X-ray data is M_(200) = (1.27 ± 0.21) × 10^(15) h ^(–1) _(70) M_⊙. The discovery of such a massive gravitationally collapsed system at high redshift provides an interesting laboratory for galaxy formation and evolution, and is a probe of extreme perturbations of the primordial matter density field. We discuss the latter, determining that, under the assumption of ΛCDM cosmology with only Gaussian perturbations, there is only a 7% chance of finding a galaxy cluster similar to SPT-CL J2106-5844 in the 2500 deg^2 SPT survey region and that only one such galaxy cluster is expected in the entire sky
Need for endoscopic removal of oesophageal coins in children was similar for strategies of immediate removal and watchful waiting
The author provides a brief commentary on the research reported in Waltzman ML, Baskin M, Wypij D, et al. A randomized clinical trial of the management of esophageal coins in children. Pediatrics 2005;116:614–9
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