1,184 research outputs found
Hepatocyte Growth Factor Receptor c-Met Instructs T Cell Cardiotropism and Promotes T Cell Migration to the Heart via Autocrine Chemokine Release
© 2015 The Authors. Published by Elsevier Inc.
This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)This study was funded by the British Heart Foundation (RG/09/002/2642 to F.M.M.-B.) and the Medical Research Council of the UK (G0901084 to F.M.M.-B.). ImageStream X was funded by the Wellcome Trust (101604/Z/13/Z). This work forms part of the research themes contributing to the translational research portfolio of Barts and the London Cardiovascular Biomedical Research Unit, which is supported and funded by the National Institute of Health Research
A simple method of estimating folic acid absorption (a modified faecal excretion method)
This article does not have an abstract
On the screening of static electromagnetic fields in hot QED plasmas
We study the screening of static magnetic and electric fields in massless
quantum electrodynamics (QED) and massless scalar electrodynamics (SQED) at
temperature . Various exact relations for the static polarisation tensor are
first reviewed and then verified perturbatively to fifth order (in the
coupling) in QED and fourth order in SQED, using different resummation
techniques. The magnetic and electric screening masses squared, as defined
through the pole of the static propagators, are also calculated to fifth order
in QED and fourth order in SQED, and their gauge-independence and
renormalisation-group invariance is checked. Finally, we provide arguments for
the vanishing of the magnetic mass to all orders in perturbation theory.Comment: 37 pages, 8 figure
The Finite Temperature SU(2) Savvidy Model with a Non-trivial Polyakov Loop
We calculate the complete one-loop effective potential for SU(2) gauge bosons
at temperature T as a function of two variables: phi, the angle associated with
a non-trivial Polyakov loop, and H, a constant background chromomagnetic field.
Using techniques broadly applicable to finite temperature field theories, we
develop both low and high temperature expansions. At low temperatures, the real
part of the effective potential V_R indicates a rich phase structure, with a
discontinuous alternation between confined (phi=pi) and deconfined phases
(phi=0). The background field H moves slowly upward from its zero-temperature
value as T increases, in such a way that sqrt(gH)/(pi T) is approximately an
integer. Beyond a certain temperature on the order of sqrt(gH), the deconfined
phase is always preferred. At high temperatures, where asymptotic freedom
applies, the deconfined phase phi=0 is always preferred, and sqrt(gH) is of
order g^2(T)T. The imaginary part of the effective potential is non-zero at the
global minimum of V_R for all temperatures. A non-perturbative magnetic
screening mass of the form M_m = cg^2(T)T with a sufficiently large coefficient
c removes this instability at high temperature, leading to a stable
high-temperature phase with phi=0 and H=0, characteristic of a
weakly-interacting gas of gauge particles. The value of M_m obtained is
comparable with lattice estimates.Comment: 28 pages, 5 eps figures; RevTeX 3 with graphic
Emotions and Digital Well-being. The rationalistic bias of social media design in online deliberations
In this chapter we argue that emotions are mediated in an incomplete way in online social media because of the heavy reliance on textual messages which fosters a rationalistic bias and an inclination towards less nuanced emotional expressions. This incompleteness can happen either by obscuring emotions, showing less than the original intensity, misinterpreting emotions, or eliciting emotions without feedback and context. Online interactions and deliberations tend to contribute rather than overcome stalemates and informational bubbles, partially due to prevalence of anti-social emotions. It is tempting to see emotions as being the cause of the problem of online verbal aggression and bullying. However, we argue that social media are actually designed in a predominantly rationalistic way, because of the reliance on text-based communication, thereby filtering out social emotions and leaving space for easily expressed antisocial emotions. Based on research on emotions that sees these as key ingredients to moral interaction and deliberation, as well as on research on text-based versus non-verbal communication, we propose a richer understanding of emotions, requiring different designs of online deliberation platforms. We propose that such designs should move from text-centred designs and should find ways to incorporate the complete expression of the full range of human emotions so that these can play a constructive role in online deliberations
Spectral function of spinless fermions on a one-dimensional lattice
We study the spectral function of interacting one-dimensional fermions for an
integrable lattice model away from half-filling. The divergent power-law
singularity of the spectral function near the single-particle or single-hole
energy is described by an effective x-ray edge type model. At low densities and
for momentum near the zone boundary, we find a second divergent singularity at
higher energies which is associated with a two-particle bound state. We use the
Bethe ansatz solution of the model to calculate the exact singularity exponents
for any momentum and for arbitrary values of chemical potential and interaction
strength in the critical regime. We relate the singularities of the spectral
function to the long-time decay of the fermion Green's function and compare our
predictions with numerical results from the time-dependent density matrix
renormalization group (tDMRG). Our results show that the tDMRG method is able
to provide accurate time decay exponents in the cases of power-law decay of the
Green's function. Some implications for the line shape of the dynamical
structure factor away from half-filling are also discussed. In addition, the
spectral weight of the Luttinger liquid result for the dynamical structure
factor of the Heisenberg model at zero field is compared with the exact
two-spinon contribution.Comment: 30 pages, 18 figure
Quark-Gluon Plasma as a Condensate of Z(3) Wilson Lines
Effective theories for the thermal Wilson line are constructed in an SU(N)
gauge theory at nonzero temperature. I propose that the order of the
deconfining phase transition for Z(N) Wilson lines is governed by the behavior
of SU(N) Wilson lines. In a mean field theory, the free energy in the
deconfined phase is controlled by the condensate for Z(N) Wilson lines.
Numerical simulations on the lattice, and the mean field theory for Z(3) Wilson
lines, suggest that about any finite temperature transition in QCD, the
dominant correlation length increases by a large, uniform factor, of order
five.Comment: 5 pages, LaTe
Connection between Chiral Symmetry Restoration and Deconfinement
We propose a simple explanation for the connection between chiral symmetry
restoration and deconfinement in QCD at high temperature. In the Higgs
description of the QCD vacuum both spontaneous chiral symmetry breaking and
effective gluon masses are generated by the condensate of a color octet
quark-antiquark pair. The transition to the high temperature state proceeds by
the melting of this condensate. Quarks and gluons become (approximately)
massless at the same critical temperature. For instanton-dominated effective
multiquark interactions and three light quarks with equal mass we find a first
order phase transition at a critical temperature around 170 MeV.Comment: New section on vortices,33 pages,LaTe
Two flavor chiral phase transition from nonperturbative flow equations
We employ nonperturbative flow equations to compute the equation of state for
two flavor QCD within an effective quark meson model. This yields the
temperature and quark mass dependence of quantities like the chiral condensate
or the pion mass. A precision estimate of the universal critical equation of
state for the three-dimensional O(4) Heisenberg model is presented. We
explicitly connect the O(4) universal behavior near the critical temperature
and zero quark mass with the physics at zero temperature and a realistic pion
mass. For realistic quark masses the pion correlation length near T_c turns out
to be smaller than its zero temperature value.Comment: 49 pages including 15 figures, LaTeX, uses epsf.sty and rotate.st
News from Lattice QCD on Heavy Quark Potentials and Spectral Functions of Heavy Quark States
We discuss recent lattice results on in-medium properties of hadrons and
focus on thermal properties of heavy quark bound states. We will clarify the
relation between heavy quark free energies and potentials used to analyze the
melting of heavy quark bound states. Furthermore, we present calculations of
meson spectral functions which indicate that the charmonium ground states,
J/psi and eta_c, persist in the quark gluon plasma as well defined resonances
with no significant change of their zero temperature masses at least up to T ~
1.5 T_c. We also briefly comment on the current status of lattice calculations
at non-vanishing baryon number density.Comment: Plenary talk at the 17th International Conference on Ultra
Relativistic Nucleus-Nucleus Collisions (Quark Matter 2004), Oakland,
California, 11-17 Jan 2004. Submitted to J.Phys.
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