25,112 research outputs found
CMS Central Hadron Calorimeter
We present a description of the CMS central hadron calorimeter. We describe
the production of the 1996 CMS hadron testbeam module. We show the results of
the quality control tests of the testbeam module. We present some results of
the 1995 CMS hadron testbeam.Comment: 7 pages, 11 Figures, corresponding author: H. Budd, [email protected]
High-Speed Projects in the United States: Identifying the Elements for Success-Part 1, MTI Report 05-01
For almost half a century, high-speed ground transportation (HSGT) has held the promise of fast, convenient, and environmentally sound travel for distances between 40 and 600 miles. While a number of HSGT systems have been developed and deployed in Asia and Europe, none has come close to being implemented in the United States. Yet this is not for lack of trying. There have been several efforts around the country, most of which have failed, some of which are still in the early stages, and a few of which might come to pass.
The goal of this study was to identify lessons learned for successfully developing and implementing high-speed rail (HSR) in the United States. Through a broad literature review, interviews, and three specific case studies—Florida, California, and the Pacific Northwest—this study articulates those lessons and presents themes for future consideration
The Bizarre Spectral Variability of Central Stars of Planetary Nebulae
A radial velocity (RV) survey to detect central stars in binary systems was
carried out between 2002 and 2004. De Marco et al. (2004) reported that 10 out
of 11 monitored stars exhibited strong RV variability, but periods were not
detected. Since other mechanisms, such as wind variability, can cause apparent
RV variations, we monitored 4 of the 10 RV-variable stars at echelle
resolutions to determine the origin of the variability. Although RV changes are
confirmed for all four stars, none of them can be ascribed to binarity at this
time. However, only for IC4593 is wind variability able to explain most (though
not all) spectral variability. For BD+332642, no wind and no pulsations appear
to be the origin of the RV changes. Finally, M1-77 and M2-54, both known to be
irregular photometric variables, exhibit dramatic RV and line shape variability
of the hydrogen and HeI absorption lines, as well as large RV variability of
weaker lines, which do not change in shape. There is no satisfactory
explanation of this variability, though a combination of wind variability and
pulsations is still the best guess at what makes these stars so variable. We
suggest that luminous central stars are ill suited to detect spectroscopic
binaries, because winds (and possibly pulsations) are pervasive and would mask
even strong periodicities. It it likely that a sample of intrinsically faint
central stars would more readily yield binary information.Comment: 7 pages, 3 figures. To appear in the proceedings of the conference
"Asymmetric Planetary Nebulae IV
Bit-String Models for Parasex
We present different bit-string models of haploid asexual populations in
which individuals may exchange part of their genome with other individuals
(parasex) according to a given probability. We study the advantages of this
parasex concerning population sizes, genetic fitness and diversity. We find
that the exchange of genomes always improves these features.Comment: 12 pages including 7 figure
Testing the gaugino AMSB model at the Tevatron via slepton pair production
Gaugino AMSB models-- wherein scalar and trilinear soft SUSY breaking terms
are suppressed at the GUT scale while gaugino masses adopt the AMSB form--
yield a characteristic SUSY particle mass spectrum with light sleptons along
with a nearly degenerate wino-like lightest neutralino and quasi-stable
chargino. The left- sleptons and sneutrinos can be pair produced at
sufficiently high rates to yield observable signals at the Fermilab Tevatron.
We calculate the rate for isolated single and dilepton plus missing energy
signals, along with the presence of one or two highly ionizing chargino tracks.
We find that Tevatron experiments should be able to probe gravitino masses into
the ~55 TeV range for inoAMSB models, which corresponds to a reach in gluino
mass of over 1100 GeV.Comment: 14 pages including 6 .eps figure
Kinematics and Composition of the Galactic Bulge: Recent Progress
We present recent results from a Keck study of the composition of the
Galactic bulge, as well as results from the bulge Bulge Radial Velocity Assay
(BRAVA). Culminating a 10 year investigation, Fulbright, McWilliam, & Rich
(2006, 2007) solved the problem of deriving the iron abundance in the Galactic
bulge, and find enhanced alpha element abundances, consistent with the earlier
work of McWilliam & Rich (1994). We also report on a radial velocity survey of
{\sl 2MASS}-selected M giant stars in the Galactic bulge, observed with the
CTIO 4m Hydra multi-object spectrograph. This program is to test dynamical
models of the bulge and to search for and map any dynamically cold substructure
in the Galactic bulge. We show initial results on fields at and . We construct a longitude-velocity plot for
the bulge stars and the model data, and find that contrary to previous studies,
the bulge does not rotate as a solid body; from the
rotation curve has a slope of and flattens considerably
at greater and reaches a maximum rotation of
(heliocentric) or (Galactocentric). This rotation is
slower than that predicted by the dynamical model of Zhao (1996).Comment: 6 pages, 6 figures, contributed paper at IAU Symposium 245 "Formation
and Evolution of Galactic Bulges
Misidentification subtype of alzheimer's disease psychosis predicts a faster cognitive decline
The presence of psychosis is associated with more rapid decline in Alzheimer's disease (AD), but the impact of paranoid (persecutory delusions) and misidentification (misperceptions and/or hallucinations) subtypes of psychosis on the speed of decline in AD is still unclear. Here we analysed data on Alzheimer's Disease Neuroimaging Initiative (ADNI)2 participants with late mild cognitive impairment or AD and we described individual trajectories of Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-cog) scores using a semi-mechanistic, logistic model, with a mixed effects based approach, which accounted for drop-out, and adjusted for baseline Mini Mental State Examination scores. The covariate model included psychosis subtypes, age, gender, education, medications and Apo-e ε4 genotype. We found that ADAS-cog rate of increase was doubled in misidentification (βr,misid_subtype =0.63, p=0.031) and mixed (both subtypes) ((βr,mixed_subtype =0.70, p=0.003) compared to non-psychotic (or paranoid) subjects suggesting that the misidentification subtype may represent a distinct AD sub-phenotype associated with an accelerated pathological process. This article is protected by copyright. All rights reserved
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