11,957 research outputs found
Discovery and Assessment of New Target Sites for Anti-HIV Therapies
Human immunodeficiency virus (HIV) infects cells by endocytosis and takes over parts of the cellâs reaction pathways in order to reproduce itself and spread the infection. One such pathway taken over by HIV becomes the inflammatory pathway which uses Nuclear Factor ÎșB (NF-ÎșB) as the principal transcription factor. Therefore, knocking out the NF-ÎșB pathway would prevent HIV from reproducing itself. In this report, our goal is to produce a simple model for this pathway with which we can identify potential targets for anti-HIV therapies and test out various hypotheses. We present a very simple model with four coupled first-order ODEs and see what happens if we treat IÎșK concentration as a parameter that can be controlled (by some unspecified means). In Section 3, we augment this model to account for activation and deactivation of IÎșK, which is controlled (again, by some unspecified means) by TNF
Inelastic fingerprints of hydrogen contamination in atomic gold wire systems
We present series of first-principles calculations for both pure and hydrogen
contaminated gold wire systems in order to investigate how such impurities can
be detected. We show how a single H atom or a single H2 molecule in an atomic
gold wire will affect forces and Au-Au atom distances under elongation. We
further determine the corresponding evolution of the low-bias conductance as
well as the inelastic contributions from vibrations. Our results indicate that
the conductance of gold wires is only slightly reduced from the conductance
quantum G0=2e^2/h by the presence of a single hydrogen impurity, hence making
it difficult to use the conductance itself to distinguish between various
configurations. On the other hand, our calculations of the inelastic signals
predict significant differences between pure and hydrogen contaminated wires,
and, importantly, between atomic and molecular forms of the impurity. A
detailed characterization of gold wires with a hydrogen impurity should
therefore be possible from the strain dependence of the inelastic signals in
the conductance.Comment: 5 pages, 3 figures, Contribution to ICN+T2006, Basel, Switzerland,
July-August 200
Coupling Nitrogen Vacancy Centers in Diamond to Superconducting Flux Qubits
We propose a method to achieve coherent coupling between Nitrogen-vacancy
(NV) centers in diamond and superconducting (SC) flux qubits. The resulting
coupling can be used to create a coherent interaction between the spin states
of distant NV centers mediated by the flux qubit. Furthermore, the magnetic
coupling can be used to achieve a coherent transfer of quantum information
between the flux qubit and an ensemble of NV centers. This enables a long-term
memory for a SC quantum processor and possibly an interface between SC qubits
and light.Comment: Accepted in Phys. Rev. Lett. Updated text and Supplementary Material
adde
Finite hadronization time and unitarity in quark recombination model
The effect of finite hadronization time is considered in the recombination
model, and it is shown that the hadron multiplicity turns out to be
proportional to the initial quark density and unitarity is conserved in the
model. The baryon to meson ratio increases rapidly with the initial quark
density due to competition among different channels.Comment: 4 pages in RevTeX, 3 eps figures, to appear in J. Phys.G as a lette
Observation of modified hadronization in relativistic Au+Au collisions: a promising signature for deconfined quark-gluon matter
Measurements of identified particles from Au+Au collisions at
GeV are reviewed. Emphasis is placed on nuclear
modification, baryon-to-meson ratios, and elliptic flow at intermediate
transverse momentum ( GeV/c). Possible connections between (1)
these measurements, (2) the running coupling for static quark anti-quark pairs
at finite temperature, and (3) the creation of a deconfined quark-gluon phase
are presented. Modifications to hadronization in Au+Au collisions are proposed
as a likely signature for the creation of deconfined colored matter.Comment: 8 pages, 5 figures, invited talk at the Strange Quark Matter 2004
conference, Cape Town, South Afric
Effect of beam on wave run-up on composite beach, Proc. ASCE, Vol. 89 (WW2), Mu 1963, Publication No. 225-224 (63-12)
Evidence from Identified Particles for Active Quark and Gluon Degrees of Freedom
Measurements of intermediate pT (1.5 < pT < 5.0 GeV/c) identified particle
distributions in heavy ion collisions at SPS and RHIC energies display striking
dependencies on the number of constituent quarks in the corresponding hadron.
One finds that elliptic flow at intermediate pT follows a constituent quark
scaling law as predicted by models of hadron formation through coalescence. In
addition, baryon production is also found to increase with event multiplicity
much faster than meson production. The rate of increase is similar for all
baryons, and seemingly independent of mass. This indicates that the number of
constituent quarks determines the multiplicity dependence of identified hadron
production at intermediate pT. We review these measurements and interpret the
experimental findings.Comment: 8 pages, 5 figures, proceedings for SQM2006 conference in Los Angele
Hadronization of Dense Partonic Matter
The parton recombination model has turned out to be a valuable tool to
describe hadronization in high energy heavy ion collisions. I review the model
and revisit recent progress in our understanding of hadron correlations. I also
discuss higher Fock states in the hadrons, possible violations of the elliptic
flow scaling and recombination effects in more dilute systems.Comment: 8 pages, 4 figures; plenary talk delivered at SQM 2006, to appear in
J. Phys.
Divergence-type 2+1 dissipative hydrodynamics applied to heavy-ion collisions
We apply divergence-type theory (DTT) dissipative hydrodynamics to study the
2+1 space-time evolution of the fireball created in Au+Au relativistic
heavy-ion collisions at 200 GeV. DTTs are exact hydrodynamic
theories that do no rely on velocity gradient expansions and therefore go
beyond second-order theories. We numerically solve the equations of motion of
the DTT for Glauber initial conditions and compare the results with those of
second-order theory based on conformal invariants (BRSS) and with data. We find
that the charged-hadron minumum-bias elliptic flow reaches its maximum value at
lower in the DTT, and that the DTT allows for a value of
slightly larger than that of the BRSS. Our results show that the differences
between viscous hydrodynamic formalisms are a significant source of uncertainty
in the precise extraction of from experiments.Comment: v4: 29 pages, 12 figures, minor changes. Final version as published
in Phys. Rev.
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