3,831 research outputs found
Structure of ternary additive hard-sphere fluid mixtures
Monte Carlo simulations on the structural properties of ternary fluid
mixtures of additive hard spheres are reported. The results are compared with
those obtained from a recent analytical approximation [S. B. Yuste, A. Santos,
and M. Lopez de Haro, J. Chem. Phys. 108, 3683 (1998)] to the radial
distribution functions of hard-sphere mixtures and with the results derived
from the solution of the Ornstein-Zernike integral equation with both the
Martynov-Sarkisov and the Percus-Yevick closures. Very good agreement between
the results of the first two approaches and simulation is observed, with a
noticeable improvement over the Percus-Yevick predictions especially near
contact.Comment: 11 pages, including 8 figures; A minor change; accepted for
publication in PR
Factors contributing to the time taken to consult with symptoms of lung cancer: a cross-sectional study
<b>Objectives</b>: To determine what factors are associated with the time people take to consult with symptoms of lung cancer, with a focus on those from rural and socially deprived areas.
<b>Methods</b>: A cross-sectional quantitative interview survey was performed of 360 patients with newly diagnosed primary lung cancer in three Scottish hospitals (two in Glasgow, one in NE Scotland). Supplementary data were obtained from medical case notes. The main outcome measures were the number of days from (1) the date participant defined first symptom until date of presentation to a medical practitioner; and (2) the date of earliest symptom from a symptom checklist (derived from clinical guidelines) until date of presentation to a medical practitioner.
<b>Results</b>: 179 participants (50%) had symptoms for more than 14 weeks before presenting to a medical practitioner (median 99 days; interquartile range 31â381). 270 participants (75%) had unrecognised symptoms of lung cancer. There were no significant differences in time taken to consult with symptoms of lung cancer between rural and/or deprived participants compared with urban and/or affluent participants. Factors independently associated with increased time before consulting about symptoms were living alone, a history of chronic obstructive pulmonary disease (COPD) and longer pack years of smoking. Haemoptysis, new onset of shortness of breath, cough and loss of appetite were significantly associated with earlier consulting, as were a history of chest infection and renal failure.
<b>Conclusion</b>: For many people with lung cancer, regardless of location and socioeconomic status, the time between symptom onset and consultation was long enough to plausibly affect prognosis. Long-term smokers, those with COPD and/or those living alone are at particular risk of taking longer to consult with symptoms of lung cancer and practitioners should be alert to this
Peanut oil press for developing countries
Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2006.Includes bibliographical references (leaves 34-35).Despite the problems with obesity that the United States is facing today, malnutrition, caused in part by severely low dietary fat consumption, remains a problem among many people living in Sub-Saharan Africa. According to the World Health Organization, one third of people in developing countries are malnourished as well as vitamin or mineral deficient. While villagers do not have access to commercially produced vegetable oil (a common source of dietary fat), nor are industrial scale oil extraction methods appropriate for small scale production. As a result, they turn to traditional methods, such as a mortar and pestle, to extract oil from peanuts, sunflower seeds, and other oil bearing seeds and nuts. This process is both time and labor intensive, and still does not yield sufficient amounts of oil to satisfy the need for it. The need for a small scale press is clear. This thesis introduces a simple design which achieves a yield of 46.9 mL per cup (U.S.) which matches the yield produced using industrial technologies. This corresponds to 153% increase in yield and 38.5% increase in rate over using traditional methods such as a mortar and pestle. The design consists of two fixed plates connected by four rods, with a third plate which slides along the four guide rods.(cont.) A standard scissor jack is the mechanism by which the necessary pressure of 800-1000 psi is generated to extract the oil. A peanut container with a removable bottom holds the peanuts as they are pressed, and holes drilled into its cylindrical face allow the oil to spill out into a collection dish underneath the container. The entire design is compact, with a footprint of one square foot and a height of 22 inches. This is 12 times smaller than the Beilenberg ram press, the standard for small scale presses currently used in developing countries. Experimental results of the loading profile as function of time show that the jack does not need to be turned continuously once the oil begins to appear. This requires significantly less strength than current methods of oil extraction. Although future work is recommended to further develop and improve the press, it shows promise of alleviating the need for such a device in many impoverished parts of the world.by Neera Jain and Somin Lee.S.B
A Note on Chern-Simons Solitons - a type III vortex from the wall vortex
We study some properties of topological Chern-Simons vortices in 2 + 1
dimensions. As has already been understood in the past, in the large magnetic
flux limit, they are well described by a Chern-Simons domain wall, which has
been compactified on a circle with the symmetric phase inside and the
asymmetric phase on the outside. Our goal is two-fold. First we want to explore
how the tension depends on the magnetic flux discretized by the integer n. The
BPS case is already known, but not much has been explored about the non-BPS
potentials. A generic renormalizable potential has two dimensionless parameters
that can be varied. Variation of only one of them lead to a type I and type II
vortex, very similar to the Abrikosov-Nielsen-Olesen (ANO) case. Variation of
both the parameters leads to a much richer structure. In particular we have
found a new type of vortex, which is type I-like for small flux and then turns
type II-like for larger flux. We could tentatively denote it a type III vortex.
This results in a stable vortex with number of fluxes which can be greater than
one. Our second objective is to study the Maxwell-Chern-Simons theory and and
understand how the large n limit of the CS vortex is smoothly connected with
the large n limit of the ANO vortex.Comment: 27 pages, 17 figures; v2.: references added, subsection 3.2 added,
explanation added in section 2.
Variable number of tandem repeat markers in the genome sequence of Mycosphaerella fijiensis, the causal agent of black leaf streak disease of banana (Musa spp)
ABSTRACT. We searched the genome of Mycosphaerella fijiensis for molecular markers that would allow population genetics analysis of this plant pathogen. M. fijiensis, the causal agent of banana leaf streak disease, also known as black Sigatoka, is the most devastating pathogen attacking bananas (Musa spp). Recently, the entire genome sequence of M. fijiensis became available. We screened this database for VNTR markers. Forty-two primer pairs were selected for validation, based on repeat type and length and the number of repeat units. Five VNTR markers showing multiple alleles were validated with a reference set of isolates from different parts of the world and a population from a banana plantation in Costa Rica. Polymorphism information content values varied from 0.6414 to 0.7544 for the reference set and from 0.0400 and 0.7373 for the population set. Eighty percent of the polymorphism information content values were above 0.60, indicating that the markers are highly informative. These markers allowed robust scoring of agarose gels and proved to be useful for variability and population genetics studies. In conclusion, the strategy we developed to identify and validate VNTR markers is an efficient means to incorporate markers that can be used for fungicide resistance management and to develop breeding strategies to control banana black leaf streak disease. This is the first report of VNTR-minisatellites from the M. fijiensis genome sequence. Key words: Molecular markers; VNTRs; Genetic diversity; Population genetics; Black Sigatok
The controlled teleportation of an arbitrary two-atom entangled state in driven cavity QED
In this paper, we propose a scheme for the controlled teleportation of an
arbitrary two-atom entangled state
in driven cavity QED.
An arbitrary two-atom entangled state can be teleported perfectly with the help
of the cooperation of the third side by constructing a three-atom GHZ entangled
state as the controlled channel. This scheme does not involve apparent (or
direct) Bell-state measurement and is insensitive to the cavity decay and the
thermal field. The probability of the success in our scheme is 1.0.Comment: 10 page
Monte Carlo Simulations with Indefinite and Complex-Valued Measures
A method is presented to tackle the sign problem in the simulations of
systems having indefinite or complex-valued measures. In general, this new
approach is shown to yield statistical errors smaller than the crude Monte
Carlo using absolute values of the original measures. Exactly solvable,
one-dimensional Ising models with complex temperature and complex activity
illustrate the considerable improvements and the workability of the new method
even when the crude one fails.Comment: 10 A4 pages, postscript (140K), UM-P-93-7
EYM equations in the presence of q-stars
We study Einstein-Yang-Mills equations in the presence of gravitating
non-topological soliton field configurations, of q-ball type. We produce
numerical solutions, stable with respect to gravitational collapse and to
fission into free particles, and we study the effect of the field strength and
the eigen-frequency to the soliton parameters. We also investigate the
formation of such soliton stars when the spacetime is asymptotically anti de
Sitter.Comment: 11 pages, to appear in Phys. Rev.
Analysis on dynamic tensile extrusion behavior of UFG OFHC Cu
Dynamic tensile extrusion (DTE) tests with the strain rate order of similar to 10(5) s(-1) were conducted on coarse grained (CG) Cu and ultrafine grained (UFG) Cu. ECAP of 16 passes with route B-c was employed to fabricate UFG Cu. DTE tests were carried out by launching the sphere samples to the conical extrusion die at a speed of similar to 475 m/sec in a vacuumed gas gun system. UFG Cu was fragmented into 3 pieces and showed a DTE elongation of similar to 340%. CG Cu exhibited a larger DTE elongation of similar to 490% with fragmentation of 4 pieces. During DTE tests, dynamic recrystallization occurred in UFG Cu, but not in CG Cu. In order to examine the DTE behavior of CG Cu and UFG Cu under very high strain rates, a numerical analysis was undertaken by using a commercial finite element code (LS-DYNA 2D axis-symmetric model) with the Johnson - Cook model. The numerical analysis correctly predicted fragmentation and DTE elongation of CG Cu. But, the experimental DTE elongation of UFG Cu was much smaller than that predicted by the numerical analysis. This difference is discussed in terms of microstructural evolution of UFG Cu during DTE tests.111Ysciescopu
Q-stars in extra dimensions
We study q-stars with global and local U(1) symmetry in extra dimensions in
asymptotically anti de Sitter or flat spacetime. The behavior of the mass,
radius and particle number of the star is quite different in 3 dimensions, but
in 5, 6, 8 and 11 dimensions is similar to the behavior in 4.Comment: 18 pages, to appear in Phys. Rev.
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