488 research outputs found
Hadronic coupling constants in lattice QCD
We report on calculations of the hadronic coupling constants
and based on lattice QCD with four flavors of dynamical staggered
fermions. By computing 2--point and 3--point Green's functions we have been
able to determine these coupling constants ab initio from QCD; the results are
compatible with the experimental values.Comment: 3 Page
Hadronic Coupling Constants in Lattice QCD
We calculate the hadronic coupling constants and
in QCD, including dynamical quarks in the framework of staggered fermions in
the lattice approach. For the nucleon--pion coupling we obtain , to be compared with the experimental value . The
coupling has been analysed for two different sets of operators
with the averaged result which is to be compared
with the experimental value .Comment: 14 pages uuencoded postscript fil
Effect of isoelectronic doping on honeycomb lattice iridate A_2IrO_3
We have investigated experimentally and theoretically the series
(NaLi)IrO. Contrary to what has been believed so far,
only for the system forms uniform solid solutions. For larger Li
content, as evidenced by powder X-ray diffraction, scanning electron microscopy
and density functional theory calculations, the system shows a miscibility gap
and a phase separation into an ordered NaLiIrO phase with
alternating Na and LiIrO planes, and a Li-rich phase close to pure
LiIrO. For we observe (1) an increase of with Li
doping up to , despite the fact that in pure LiIrO is
smaller than in NaIrO, and (2) a gradual reduction of the
antiferromagnetic ordering temperature and ordered moment. The
previously proposed magnetic quantum phase transition at may
occur in a multiphase region and its nature needs to be re-evaluated.Comment: 8 pages, 9 figures including supplemental informatio
Association of CD69 Up-Regulation on CD4+ CLA+ T cells versus patch test, strip patch test and clinical history in nickel sensitization
<p>Abstract</p> <p>Objective</p> <p>The patch test (PT) with its modification - the strip patch test (SPT) - is the standard in vivo procedure to diagnose an allergic contact dermatitis (ACD). To date, none of the in vitro tests for the diagnosis of ACD fulfils the requirements of an easy, valid and reliable test. To investigate the prediction ability of a flow cytometric assay of CD69 up-regulation on CD4+ CLA+ T cells in nickel-sensitive and non-nickel-sensitive patients.</p> <p>Methods</p> <p>In a prospective, investigator-blinded, clinical study a total of 85 nickel-sensitive (n = 44; 51.8%) and non-nickel-sensitive patients (n = 41; 48.2%) were enrolled. The association between CD69 up-regulation on CD4+ CLA+ T cells on the one hand and PT, SPT, and clinical history on the other hand was measured. Association is expressed with c statistic values (receiver operating characteristic analysis) and corresponding 95% CIs.</p> <p>Results</p> <p>The associations were c = 0.57 (95% CI: 0.42-0.72) between CD69 up-regulation and PT, c = 0.49 (95% CI: 0.36-0.62) between CD69 up-regulation and SPT, and c = 0.51 (95% CI: 0.37-0.64) between CD69 up-regulation and clinical history.</p> <p>Conclusions</p> <p>CD69 up-regulation on CD4+ CLA+ T cells in vitro could not predict neither a positive PT or SPT result nor a positive clinical history to nickel sulfate. The combination of clinical history and patch testing still remains the basis for diagnosing ACD.</p
Collective excitations of a degenerate gas at the BEC-BCS crossover
We study collective excitation modes of a fermionic gas of Li atoms in
the BEC-BCS crossover regime. While measurements of the axial compression mode
in the cigar-shaped trap close to a Feshbach resonance confirm theoretical
expectations, the radial compression mode shows surprising features. In the
strongly interacting molecular BEC regime we observe a negative frequency shift
with increasing coupling strength. In the regime of a strongly interacting
Fermi gas, an abrupt change in the collective excitation frequency occurs,
which may be a signature for a transition from a superfluid to a collisionless
phase.Comment: Feshbach resonance position updated, few minor change
Planar manipulation of magneto-tactic bacteria using unidirectional magnetic fields
We show for the first time that an alternating unidirectional magnetic field generated by a magnetic erase head allows planar manipulation of magneto-tactic bacteria (MTB), and is not restricted to parallel directions only. We used squared-shaped magnetic fields of approximately 4 mT while sweeping from 0.25 to 10 Hz, and found that at frequencies of over 3 Hz the mean orthogonal velocity becomes constant. The erase head offers a significant reduction in size and complexity over conventional manipulators
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