832 research outputs found
On the presence of nonjet "higher harmonic" components in 2D angular correlations from high energy heavy ion collisions
It is conjectured that several higher harmonic flows may result from
initial-state geometry fluctuations in \aa collisions coupled to a
radially-expanding medium. But as with "elliptic flow" measurements,
non-hydrodynamic mechanisms such as jet production may contribute to other
higher azimuth multipoles as biases. Careful distinctions should be
maintained between jet-related and nonjet (possibly hydrodynamic) contributions
to (e.g., "nonflow" and "flow"). In this study we consider several
questions: (a) To what extent do jet-like structures in two-dimensional (2D)
angular correlations contribute to azimuth multipoles inferred from various
methods? (b) If a multipole element is added to a 2D fit model is a
nonzero amplitude indicative of a corresponding flow component? and (c) Can 2D
correlations establish the necessity of nonjet contributions to some or all
higher multipoles? Model fits to 2D angular correlations are used to establish
the origins of azimuth multipoles inferred from 1D projections onto azimuth or
from nongraphical numerical methods. We find that jet-like angular
correlations, and specifically a 2D peak at the angular origin consistent with
jet production, constitute the dominant contribution to inferred higher
multipoles, and the data do not {\em require} higher multipoles in isolation
from the jet-like 2D peak. Inference of "higher harmonic flows" results from
identifying certain nominally jet-like structure as flow manifestations through
unjustified application of 1D Fourier series analysis. Although the peak
structure at the angular origin is strongly modified in more-central collisions
some properties remain compatible with relevant pQCD theory expectations for
jet production.Comment: 14 pages, 11 figure
Applicability of Monte Carlo Glauber models to relativistic heavy ion collision data
The accuracy of Monte Carlo Glauber model descriptions of minimum-bias
multiplicity frequency distributions is evaluated using data from the
Relativistic Heavy Ion Collider (RHIC) within the context of a sensitive,
power-law representation introduced previously by Trainor and Prindle (TP).
Uncertainties in the Glauber model input and in the mid-rapidity multiplicity
frequency distribution data are reviewed and estimated using the TP centrality
methodology. The resulting errors in model-dependent geometrical quantities
used to characterize heavy ion collisions ({\em i.e.} impact parameter, number
of nucleon participants , number of binary interactions ,
and average number of binary collisions per incident participant nucleon )
are presented for minimum-bias Au-Au collisions at = 20, 62,
130 and 200 GeV and Cu-Cu collisions at = 62 and 200 GeV.
Considerable improvement in the accuracy of collision geometry quantities is
obtained compared to previous Monte Carlo Glauber model studies, confirming the
TP conclusions. The present analysis provides a comprehensive list of the
sources of uncertainty and the resulting errors in the above geometrical
collision quantities as functions of centrality. The capability of energy
deposition data from trigger detectors to enable further improvements in the
accuracy of collision geometry quantities is also discussed.Comment: 27 pages, 4 figures, 11 table
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TASTEX gamma spectrometer system for measuring isotopic and total plutonium concentrations in solutions
Described is a computer-based gamma ray spectrometer system using a germanium detector for rapid nondestructive measurement of isotopic and total plutonium concentrations in solutions at nuclear reprocessing plants. Isotopic concentrations have been measured with an accuracy of +-0.5%. Cell design, calibration techniques, and preliminary results are discussed. This system is being installed at the Tokai reprocessing plant in Japan
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Half-life of /sup 239/Pu as determined by pulse-counting mass spectrometry
The half-life of /sup 239/Pu was measured by determining the ingrowth of /sup 235/U during a known time by isotope dilution mass spectrometry techniques
The Otterbein Miscellany - June 1982
https://digitalcommons.otterbein.edu/miscellany/1006/thumbnail.jp
Discovery and Validation of a New Class of Small Molecule Toll-Like Receptor 4 (TLR4) Inhibitors
Many inflammatory diseases may be linked to pathologically elevated signaling via the receptor for lipopolysaccharide (LPS), toll-like receptor 4 (TLR4). There has thus been great interest in the discovery of TLR4 inhibitors as potential anti-inflammatory agents. Recently, the structure of TLR4 bound to the inhibitor E5564 was solved, raising the possibility that novel TLR4 inhibitors that target the E5564-binding domain could be designed. We utilized a similarity search algorithm in conjunction with a limited screening approach of small molecule libraries to identify compounds that bind to the E5564 site and inhibit TLR4. Our lead compound, C34, is a 2-acetamidopyranoside (MW 389) with the formula C17H27NO9, which inhibited TLR4 in enterocytes and macrophages in vitro, and reduced systemic inflammation in mouse models of endotoxemia and necrotizing enterocolitis. Molecular docking of C34 to the hydrophobic internal pocket of the TLR4 co-receptor MD-2 demonstrated a tight fit, embedding the pyran ring deep inside the pocket. Strikingly, C34 inhibited LPS signaling ex-vivo in human ileum that was resected from infants with necrotizing enterocolitis. These findings identify C34 and the β-anomeric cyclohexyl analog C35 as novel leads for small molecule TLR4 inhibitors that have potential therapeutic benefit for TLR4-mediated inflammatory diseases. © 2013 Neal et al
Production of deuterium, tritium, and He in central Pb+Pb collisions at 20A, 30A, 40A, 80A, and 158A GeV at the CERN SPS
Production of , , and He nuclei in central Pb+Pb interactions was
studied at five collision energies ( 6.3, 7.6, 8.8, 12.3, and
17.3 GeV) with the NA49 detector at the CERN SPS. Transverse momentum spectra,
rapidity distributions, and particle ratios were measured. Yields are compared
to predictions of statistical models. Phase-space distributions of light nuclei
are discussed and compared to those of protons in the context of a coalescence
approach. The coalescence parameters and , as well as coalescence
radii for and He were determined as a function of transverse mass at
all energies.Comment: 22 pages, 29 figures, 8 tables, for submission to Phys. Rev.
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