3,272 research outputs found
Connection between Calogero-Marchioro-Wolfes type few-body models and free oscillators
We establish the exact correspondence of the Calogero-Marchioro-Wolfes model
and several of its generalizations with free oscillators. This connection
yields the eigenstates and leads to a proof of the quantum integrability. The
usefulness of our method for finding new solvable models is then demonstrated
by an example.Comment: 10 pages, REVTeX, Minor correction
Renormalized Harmonic-Oscillator Description of Confined Electron Systems with Inverse-Square Interaction
An integrable model for SU() electrons with inverse-square interaction
is studied for the system with confining harmonic potential. We develop a new
description of the spectrum based on the {\it renormalized
harmonic-oscillators} which incorporate interaction effects via the repulsion
of energy levels. This approach enables a systematic treatment of the
excitation spectrum as well as the ground-state quantities.Comment: RevTex, 7 page
A Combine On-Line Acoustic Flowmeter and Fluorocarbon Coolant Mixture Analyzer for The ATLAS Silicon Tracker
An upgrade to the ATLAS silicon tracker cooling control system may require a
change from C3F8 (octafluoro-propane) to a blend containing 10-30% of C2F6
(hexafluoro-ethane) to reduce the evaporation temperature and better protect
the silicon from cumulative radiation damage with increasing LHC luminosity.
Central to this upgrade is a new acoustic instrument for the real-time
measurement of the C3F8/C2F6 mixture ratio and flow. The instrument and its
Supervisory, Control and Data Acquisition (SCADA) software are described in
this paper. The instrument has demonstrated a resolution of 3.10-3 for
C3F8/C2F6 mixtures with ~20%C2F6, and flow resolution of 2% of full scale for
mass flows up to 30gs-1. In mixtures of widely-differing molecular weight (mw),
higher mixture precision is possible: a sensitivity of < 5.10-4 to leaks of
C3F8 into the ATLAS pixel detector nitrogen envelope (mw difference 160) has
been seen. The instrument has many potential applications, including the
analysis of mixtures of hydrocarbons, vapours for semi-conductor manufacture
and anaesthesia
Bosonic and fermionic single-particle states in the Haldane approach to statistics for identical particles
We give two formulations of exclusion statistics (ES) using a variable number
of bosonic or fermionic single-particle states which depend on the number of
particles in the system. Associated bosonic and fermionic ES parameters are
introduced and are discussed for FQHE quasiparticles, anyons in the lowest
Landau level and for the Calogero-Sutherland model. In the latter case, only
one family of solutions is emphasized to be sufficient to recover ES;
appropriate families are specified for a number of formulations of the
Calogero-Sutherland model. We extend the picture of variable number of
single-particle states to generalized ideal gases with statistical interaction
between particles of different momenta. Integral equations are derived which
determine the momentum distribution for single-particle states and distribution
of particles over the single-particle states in the thermal equilibrium.Comment: 6 pages, REVTE
Development of a custom on-line ultrasonic vapour analyzer/flowmeter for the ATLAS inner detector, with application to gaseous tracking and Cherenkov detectors
Precision sound velocity measurements can simultaneously determine binary gas
composition and flow. We have developed an analyzer with custom electronics,
currently in use in the ATLAS inner detector, with numerous potential
applications. The instrument has demonstrated ~0.3% mixture precision for
C3F8/C2F6 mixtures and < 10-4 resolution for N2/C3F8 mixtures. Moderate and
high flow versions of the instrument have demonstrated flow resolutions of +/-
2% F.S. for flows up to 250 l.min-1, and +/- 1.9% F.S. for linear flow
velocities up to 15 ms-1; the latter flow approaching that expected in the
vapour return of the thermosiphon fluorocarbon coolant recirculator being built
for the ATLAS silicon tracker.Comment: Paper submitted to TWEPP2012; Topical Workshop on Electronics for
Particle Physics, Oxford, UK, September 17-21, 2012. KEYWORDS: Sonar;
Saturated fluorocarbons; Flowmetry; Sound velocity, Gas mixture analysis. 8
pages, 7 figure
Integrable Spin Chain with Reflecting End
A new integrable spin chain of the Haldane-Shastry type is introduced. It is
interpreted as the inverse-square interacting spin chain with a {\it reflecting
end}. The lattice points of this model consist of the square roots of the zeros
of the Laguerre polynomial. Using the ``exchange operator formalism'', the
integrals of motion for the model are explicitly constructed.Comment: 13 pages, REVTeX3, with minor correction
Mechanisms of oxidative stress and alterations in gene expression by Libby six-mix in human mesothelial cells
<p>Abstract</p> <p>Background</p> <p>Exposures to an amphibole fiber in Libby, Montana cause increases in malignant mesothelioma (MM), a tumor of the pleural and peritoneal cavities with a poor prognosis. Affymetrix microarray/GeneSifter analysis was used to determine alterations in gene expression of a human mesothelial cell line (LP9/TERT-1) by a non-toxic concentration (15Ă10<sup>6 </sup>ÎŒm<sup>2</sup>/cm<sup>2</sup>) of unprocessed Libby six-mix and negative (glass beads) and positive (crocidolite asbestos) controls. Because manganese superoxide dismutase (MnSOD; SOD2) was the only gene upregulated significantly (p < 0.05) at both 8 and 24 h, we measured SOD protein and activity, oxidative stress and glutathione (GSH) levels to better understand oxidative events after exposure to non-toxic (15Ă10<sup>6 </sup>ÎŒm<sup>2</sup>/cm<sup>2</sup>) and toxic concentrations (75Ă10<sup>6 </sup>ÎŒm<sup>2</sup>/cm<sup>2</sup>) of Libby six-mix.</p> <p>Results</p> <p>Exposure to 15Ă10<sup>6 </sup>ÎŒm<sup>2</sup>/cm<sup>2 </sup>Libby six-mix elicited significant (p < 0.05) upregulation of one gene (<it>SOD2</it>; 4-fold) at 8 h and 111 gene changes at 24 h, including a 5-fold increase in <it>SOD2</it>. Increased levels of SOD2 mRNA at 24 h were also confirmed in HKNM-2 normal human pleural mesothelial cells by qRT-PCR. SOD2 protein levels were increased at toxic concentrations (75Ă10<sup>6 </sup>ÎŒm<sup>2</sup>/cm<sup>2</sup>) of Libby six-mix at 24 h. In addition, levels of copper-zinc superoxide dismutase (Cu/ZnSOD; SOD1) protein were increased at 24 h in all mineral groups. A dose-related increase in SOD2 activity was observed, although total SOD activity remained unchanged. Dichlorodihydrofluorescein diacetate (DCFDA) fluorescence staining and flow cytometry revealed a dose- and time-dependent increase in reactive oxygen species (ROS) production by LP9/TERT-1 cells exposed to Libby six-mix. Both Libby six-mix and crocidolite asbestos at 75Ă10<sup>6 </sup>ÎŒm<sup>2</sup>/cm<sup>2 </sup>caused transient decreases (p < 0.05) in GSH for up to 24 h and increases in gene expression of heme oxygenase 1 (<it>HO-1</it>) in LP9/TERT-1 and HKNM-2 cells.</p> <p>Conclusions</p> <p>Libby six-mix causes multiple gene expression changes in LP9/TERT-1 human mesothelial cells, as well as increases in SOD2, increased production of oxidants, and transient decreases in intracellular GSH. These events are not observed at equal surface area concentrations of nontoxic glass beads. Results support a mechanistic basis for the importance of SOD2 in proliferation and apoptosis of mesothelial cells and its potential use as a biomarker of early responses to mesotheliomagenic minerals.</p
A novel method for the absolute fluorescence yield measurement by AIRFLY
One of the goals of the AIRFLY (AIR FLuorescence Yield) experiment is to
measure the absolute fluorescence yield induced by electrons in air to better
than 10% precision. We introduce a new technique for measurement of the
absolute fluorescence yield of the 337 nm line that has the advantage of
reducing the systematic uncertainty due to the detector calibration. The
principle is to compare the measured fluorescence yield to a well known process
- the Cerenkov emission. Preliminary measurements taken in the BFT (Beam Test
Facility) in Frascati, Italy with 350 MeV electrons are presented. Beam tests
in the Argonne Wakefield Accelerator at the Argonne National Laboratory, USA
with 14 MeV electrons have also shown that this technique can be applied at
lower energies.Comment: presented at the 5th Fluorescence Workshop, El Escorial - Madrid,
Spain, 16 - 20 September 200
Crown Lengthening Revisited
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141178/1/cap0233.pd
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