667 research outputs found
Transmission and transparent wavelength conversion of an optically labeled signal using ASK/DPSK orthogonal modulation
Chiral Magnetic Effect on the Lattice
We review recent progress on the lattice simulations of the chiral magnetic
effect. There are two different approaches to analyze the chiral magnetic
effect on the lattice. In one approach, the charge density distribution or the
current fluctuation is measured under a topological background of the gluon
field. In the other approach, the topological effect is mimicked by the chiral
chemical potential, and the induced current is directly measured. Both
approaches are now developing toward the exact analysis of the chiral magnetic
effect.Comment: to appear in Lect. Notes Phys. "Strongly interacting matter in
magnetic fields" (Springer), edited by D. Kharzeev, K. Landsteiner, A.
Schmitt, H.-U. Ye
The (11112) model on a 1+1 dimensional lattice
We study the chiral gauge model (11112) of four left-movers and one
right-mover with strong interactions in the 1+1 dimensional lattice. Exact
computations of relevant -matrix elements demonstrate a loophole that so
constructed model and its dynamics can possibly evade the ``no-go'' theorem of
Nielsen and Ninomiya.Comment: 15 pages, 1 fig. to appear in Phys. Rev.
Random walks of Wilson loops in the screening regime
Dynamics of Wilson loops in pure Yang-Mills theories is analyzed in terms of
random walks of the holonomies of the gauge field on the gauge group manifold.
It is shown that such random walks should necessarily be free. The distribution
of steps of these random walks is related to the spectrum of string tensions of
the theory and to certain cumulants of Yang-Mills curvature tensor. It turns
out that when colour charges are completely screened, the holonomies of the
gauge field can change only by the elements of the group center, which
indicates that in the screening regime confinement persists due to thin center
vortices. Thick center vortices are also considered and the emergence of such
stepwise changes in the limits of infinitely thin vortices and infinitely large
loops is demonstrated.Comment: Major revision of the previous version, to appear in Nucl. Phys. B
(10 pages RevTeX, 3 figures
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Assessing stack ventilation strategies in the continental climate of Beijing using CFD simulations
The performance of a stack ventilated building compared with two other building designs have been predicted numerically for ventilation and thermal comfort effects in a typical climate of Beijing, China. The buildings were configured based on natural ventilation. Using actual building sizes, Computational Fluid Dynamics (CFD) models were developed, simulated and analysed in Fluent, an ANSYS platform. This paper describes the general design consideration that has been incorporated, the ventilation strategies and the variation in meshing and boundary conditions. The predicted results show that the ventilation flow rates are important parameters to ensure fresh air supply. A Predicted Mean Vote (PMV) model based on ISO-7730 (2005) and the Predicted Percentage Dissatisfied (PPD) indices were simulated using Custom Field Functions (CFF) in the fluent design interface for transition seasons of Beijing. The results showed that the values of PMV are not within the standard acceptable range defined by ISO-7730
Mucoadhesive electrospun patch delivery of lidocaine to the oral mucosa and investigation of spatial distribution in tissue using MALDI-mass spectrometry imaging
Many oral mucosal conditions cause considerable and prolonged pain that to date has been difficult to alleviate via topical delivery, and the use of injection causes many patients dental anxiety and needle-prick pain. Therefore, developing a non-injectable drug delivery system as an alternative administration procedure may vastly improve the health and wellbeing of these patients. Recent advances in the development of mucoadhesive electrospun patches for the direct delivery of therapeutics to the oral mucosa offer a potential solution, but as yet, the release of local anaesthetics from this system and their uptake by oral tissue has not been demonstrated. Here, we demonstrate the fabrication of lidocaine-loaded electrospun fibre patches, drug release, and subsequent uptake and permeation through porcine buccal mucosa. Lidocaine HCl and lidocaine base were incorporated into the electrospun patches to evaluate the difference in drug permeation for the two drug compositions. Lidocaine released from the lidocaine HCl-containing electrospun patches was significantly quicker than from the lidocaine base patches, with double the amount of drug released from the lidocaine HCl patches in the first 15 minutes (0.16 ± 0.04 mg) compared to from the lidocaine base patches (0.07 ± 0.01 mg). The permeation of lidocaine from the lidocaine HCl electrospun patches through ex vivo porcine buccal mucosa was also detected in 15 minutes, whereas permeation of lidocaine from the lidocaine base patch was not detected. Matrix-assisted laser desorption ionisation – mass spectrometry imaging (MALDI-MSI) was used to investigate localisation of lidocaine within oral tissue. Lidocaine in solution as well as from the mucoadhesive patch penetrated into buccal mucosal tissue in a time-dependent manner and was detectable in the lamina propria after only 15 minutes. Moreover, the lidocaine released from lidocaine HCl electrospun patches retained biological activity, inhibiting veratridine-mediated opening of voltage-gated sodium channels in SH-SY5Y neuroblastoma cells. These data suggest that a mucoadhesive electrospun patch may be used as a vehicle for rapid uptake and sustained anaesthetic drug delivery and may reduce the need for injection
The Appearance and Disappearance of Ship Tracks on Large Spatial Scales
The 1-km advanced very high resolution radiometer observations from the morning, NOAA-12, and afternoon,
NOAA-11, satellite passes over the coast of California during June 1994 are used to determine the altitudes,
visible optical depths, and cloud droplet effective radii for low-level clouds. Comparisons are made between
the properties of clouds within 50 km of ship tracks and those farther than 200 km from the tracks in order to
deduce the conditions that are conducive to the appearance of ship tracks in satellite images. The results indicate
that the low-level clouds must be sufficiently close to the surface for ship tracks to form. Ship tracks rarely
appear in low-level clouds having altitudes greater than 1 km. The distributions of visible optical depths and
cloud droplet effective radii for ambient clouds in which ship tracks are embedded are the same as those for
clouds without ship tracks. Cloud droplet sizes and liquid water paths for low-level clouds do not constrain the
appearance of ship tracks in the imagery. The sensitivity of ship tracks to cloud altitude appears to explain why
the majority of ship tracks observed from satellites off the coast of California are found south of 358N. A small
rise in the height of low-level clouds appears to explain why numerous ship tracks appeared on one day in a
particular region but disappeared on the next, even though the altitudes of the low-level clouds were generally
less than 1 km and the cloud cover was the same for both days. In addition, ship tracks are frequent when lowlevel
clouds at altitudes below 1 km are extensive and completely cover large areas. The frequency of imagery
pixels overcast by clouds with altitudes below 1 km is greater in the morning than in the afternoon and explains
why more ship tracks are observed in the morning than in the afternoon. If the occurrence of ship tracks in
satellite imagery data depends on the coupling of the clouds to the underlying boundary layer, then cloud-top
altitude and the area of complete cloud cover by low-level clouds may be useful indices for this coupling.This work was supported in part by the Office of Naval Research and by the National Science Foundation through the Center for Clouds, Chemistry and Climate at the Scripps Institution of Oceanography, an NSF Science and Technology Center
Soft Photons in Hadron-Hadron Collisions: Synchrotron Radiation from the QCD Vacuum?
We discuss the production of soft photons in high energy hadron-hadron
collisions. We present a model where quarks and antiquarks in the hadrons emit
``synchrotron light'' when being deflected by the chromomagnetic fields of the
QCD vacuum, which we assume to have a nonperturbative structure. This gives a
source of prompt soft photons with frequencies in the c.m.
system of the collision in addition to hadronic bremsstrahlung. In comparing
the frequency spectrum and rate of ``synchrotron'' photons to experimental
results we find some supporting evidence for their existence. We make an
exclusive--inclusive connection argument to deduce from the ``synchrotron''
effect a behaviour of the neutron electric formfactor proportional
to for . We find this to be consistent with
available data. In our view, soft photon production in high energy
hadron-hadron and lepton-hadron collisions as well as the behaviour of
electromagnetic hadron formfactors for low are thus sensitive probes of
the nonperturbative structure of the QCD vacuum.Comment: Heidelberg preprint HD-THEP-94-36, 31 pages, LaTeX + ZJCITE.sty
(included), 12 figures appended as uuencoded compressed ps-fil
Multiplicity distributions at high energies as a sum of Poissonian-like distributions
It is shown that at collider energies experimental multiplicity distributions
are well parameterized by a sum of Gupta-Sarma distributions. This extends
earlier description of the lower energy data by the two parameter sum of
Poissonians. Implications of the proposed parametrization for LHC are
discussed.Comment: 16 pages, Latex, 4 EPS figure
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