2,325 research outputs found
Non-Abelian Bremsstrahlung and Azimuthal Asymmetries in High Energy p+A Reactions
We apply the GLV reaction operator solution to the Vitev-Gunion-Bertsch (VGB)
boundary conditions to compute the all-order in nuclear opacity non-abelian
gluon bremsstrahlung of event-by-event fluctuating beam jets in nuclear
collisions. We evaluate analytically azimuthal Fourier moments of single gluon,
, and even number gluon, inclusive
distributions in high energy p+A reactions as a function of harmonic ,
%independent target recoil cluster number, , and gluon number, , at
RHIC and LHC. Multiple resolved clusters of recoiling target beam jets together
with the projectile beam jet form Color Scintillation Antenna (CSA) arrays that
lead to characteristic boost non-invariant trapezoidal rapidity distributions
in asymmetric nuclear collisions. The scaling of intrinsically
azimuthally anisotropic and long range in nature of the non-abelian \br
leads to moments that are similar to results from hydrodynamic models,
but due entirely to non-abelian wave interference phenomena sourced by the
fluctuating CSA. Our analytic non-flow solutions are similar to recent
numerical saturation model predictions but differ by predicting a simple
power-law hierarchy of both even and odd without invoking
factorization. A test of CSA mechanism is the predicted nearly linear
rapidity dependence of the . Non-abelian beam jet \br may thus
provide a simple analytic solution to Beam Energy Scan (BES) puzzle of the near
independence of moments observed down to 10 AGeV where
large valence quark beam jets dominate inelastic dynamics. Recoil \br from
multiple independent CSA clusters could also provide a partial explanation for
the unexpected similarity of in and non-central at same
multiplicity as observed at RHIC and LHC.Comment: 16 pages, 10 figure
Pion and Kaon Spectra from Distributed Mass Quark Matter
After discussing some hints for possible masses of quasiparticles in quark
matter on the basis of lattice equation of state, we present pion and kaon
transverse spectra obtained by recombining quarks with distributed mass and
thermal cut power-law momenta as well as fragmenting by NLO pQCD with intrinsic
{and nuclear} broadening.Comment: Talk given at SQM 200
Curriculum Development for Teaching Swimming in Hungary
Given the lack of publications describing changing curricular matters and the role of teaching and learning swimming in Hungary, the purpose of this study was to analyze the curricula of 1995, 2001, and 2003. It also was the authors’ goal to examine the role and place of swimming instruction in school education and provide discussion points to promote further review and the possible effects on teaching methodology and skill acquisition. The authors analyzed the Hungarian curricula for the years 1995, 2001, and 2003 based on records, official documents, administrative texts, and formal reports on curricular structures and applications. They concluded that the process of continuous curricular change has impeded the process of teaching and learning swimming in Hungary and recommend that teachers and local curriculum developers make an effort to integrate the best parts of each curriculum
Modeling Eclipses in the Classical Nova V Persei: The Role of the Accretion Disk Rim
Multicolor (BVRI) light curves of the eclipsing classical nova V Per are
presented, and a total of twelve new eclipse timings are measured for the
system. When combined with previous eclipse timings from the literature, these
timings yield a revised ephemeris for the times of mid-eclipse given by HJD =
2,447,442.8260(1) + 0.107123474(3) E. The eclipse profiles are analyzed with a
parameter-fitting model that assumes four sources of luminosity: a white dwarf
primary star, a main-sequence secondary star, a flared accretion disk with a
rim, and a bright spot at the intersection of the mass-transfer stream and the
disk periphery. A matrix of model solutions are computed, covering an extensive
range of plausible parameter values. The solution matrix is then explored to
determine the optimum values for the fitting parameters and their associated
errors. For models that treat the accretion disk as a flat structure without a
rim, optimum fits require that the disk have a flat temperature profile.
Although models with a truncated inner disk (R_in >> R_wd) result in a steeper
temperature profile, steady-state models with a temperature profile
characterized by T(r) \propto r^{-3/4} are found only for models with a
significant disk rim. A comparison of the observed brightness and color at
mid-eclipse with the photometric properties of the best-fitting model suggests
that V Per lies at a distance of ~ 1 kpc.Comment: Accepted for publication in The Astrophysical Journal. Thirty-nine
pages, including 9 figures. V2 - updated to include additional references and
related discussion to previous work overlooked in the original version, and
to correct a typo in the ephemeris given in the abstract. V3 - Minor typos
corrected. The paper is scheduled for the 20 June 2006 issue of the ApJ. V4 -
An error in equation (9) has been corrected. The results presented in the
paper were not affected, as all computations were made using the correct
formulation of this equatio
Strange quark matter: mapping QCD lattice results to finite baryon density by a quasi-particle model
A quasi-particle model is presented which describes QCD lattice results for
the 0, 2 and 4 quark-flavor equation of state. The results are mapped to finite
baryo-chemical potentials. As an application of the model we make a prediction
of deconfined matter with appropriate inclusion of strange quarks and consider
pure quark stars.Comment: invited talk at Strangeness 2000, Berkeley; prepared version for the
proceedings, 5 page
Inherent noise can facilitate coherence in collective swarm motion
Among the most striking aspects of the movement of many animal groups are their sudden coherent changes in direction. Recent observations of locusts and starlings have shown that this directional switching is an intrinsic property of their motion. Similar direction switches are seen in self-propelled particle and other models of group motion. Comprehending the factors that determine such switches is key to understanding the movement of these groups. Here, we adopt a coarse-grained approach to the study of directional switching in a self-propelled particle model assuming an underlying one-dimensional Fokker–Planck equation for the mean velocity of the particles. We continue with this assumption in analyzing experimental data on locusts and use a similar systematic Fokker–Planck equation coefficient estimation approach to extract the relevant information for the assumed Fokker–Planck equation underlying that experimental data. In the experiment itself the motion of groups of 5 to 100 locust nymphs was investigated in a homogeneous laboratory environment, helping us to establish the intrinsic dynamics of locust marching bands. We determine the mean time between direction switches as a function of group density for the experimental data and the self-propelled particle model. This systematic approach allows us to identify key differences between the experimental data and the model, revealing that individual locusts appear to increase the randomness of their movements in response to a loss of alignment by the group. We give a quantitative description of how locusts use noise to maintain swarm alignment. We discuss further how properties of individual animal behavior, inferred by using the Fokker–Planck equation coefficient estimation approach, can be implemented in the self-propelled particle model to replicate qualitatively the group level dynamics seen in the experimental data
Chloride Ions in the Pore of Glycine and GABA Channels Shape the Time Course and Voltage Dependence of Agonist Currents
In the vertebrate CNS, fast synaptic inhibition is mediated by GABA and glycine receptors. We recently reported that the time course of these synaptic currents is slower when intracellular chloride is high. Here we extend these findings to measure the effects of both extracellular and intracellular chloride on the deactivation of glycine and GABA currents at both negative and positive holding potentials. Currents were elicited by fast agonist application to outside-out patches from HEK-293 cells expressing rat glycine or GABA receptors. The slowing effect of high extracellular chloride on current decay was detectable only in low intracellular chloride (4 mM). Our main finding is that glycine and GABA receptors "sense" chloride concentrations because of interactions between the M2 pore-lining domain and the permeating ions. This hypothesis is supported by the observation that the sensitivity of channel gating to intracellular chloride is abolished if the channel is engineered to become cation selective or if positive charges in the external pore vestibule are eliminated by mutagenesis. The appropriate interaction between permeating ions and channel pore is also necessary to maintain the channel voltage sensitivity of gating, which prolongs current decay at depolarized potentials. Voltage dependence is abolished by the same mutations that suppress the effect of intracellular chloride and also by replacing chloride with another permeant ion, thiocyanate. These observations suggest that permeant chloride affects gating by a foot-in-the-door effect, binding to a channel site with asymmetrical access from the intracellular and extracellular sides of the membrane
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