787 research outputs found
Tkachenko polarons in vortex lattices
We analyze the properties of impurities immersed in a vortex lattice formed
by ultracold bosons in the mean field quantum Hall regime. In addition to the
effects of a periodic lattice potential, the impurity is dressed by collective
modes with parabolic dispersion (Tkachenko modes). We derive the effective
polaron model, which contains a marginal impurity-phonon interaction. The
polaron spectral function exhibits a Lorentzian broadening for arbitrarily
small wave vectors even at zero temperature, in contrast with the result for
optical or acoustic phonons. The anomalous damping of Tkachenko polarons could
be detected experimentally using momentum-resolved spectroscopy.Comment: 10 pages, 2 figure
Cellular interactions in the pathogenesis of interstitial lung diseases
Interstitial lung disease (ILD) encompasses a large and diverse group of pathological conditions that share similar clinical, radiological and pathological manifestations, despite potentially having quite different aetiologies and comorbidities. Idiopathic pulmonary fibrosis (IPF) represents probably the most aggressive form of ILD and systemic sclerosis is a multiorgan fibrotic disease frequently associated with ILD. Although the aetiology of these disorders remains unknown, in this review we analyse the pathogenic mechanisms by cell of interest (fibroblast, fibrocyte, myofibroblast, endothelial and alveolar epithelial cells and immune competent cells). New insights into the complex cellular contributions and interactions will be provided, comparing the role of cell subsets in the pathogenesis of IPF and systemic sclerosis
Capture Velocity for a Magneto-Optical Trap in a Broad Range of Light Intensity
In a recent paper, we have used the dark-spot Zeeman tuned slowing technique
[Phys. Rev. A 62, 013404-1, (2000)] to measure the capture velocity as a
function of laser intensity for a sodium magneto optical trap. Due to technical
limitation we explored only the low light intensity regime, from 0 to 27
mW/cm^2. Now we complement that work measuring the capture velocity in a
broader range of light intensities (from 0 to 400 mW/cm^2). New features,
observed in this range, are important to understant the escape velocity
behavior, which has been intensively used in the interpretation of cold
collisions. In particular, we show in this brief report that the capture
velocity has a maximum as function of the trap laser intensity, which would
imply a minimum in the trap loss rates.Comment: 2 pages, 2 figure
Magnetic Field Tomography
Neutral atoms may be trapped via the interaction of their magnetic dipole
moment with magnetic field gradients. One of the possible schemes is the
cloverleaf trap. It is often desirable to have at hand a fast and precise
technique for measuring the magnetic field distribution. We introduce a novel
diagnostic tool for instantaneous imaging the equipotential lines of a magnetic
field within a region of space (the vacuum recipient) that is not accessible to
massive probes. Our technique is based on spatially resolved observation of the
fluorescence emitted by a hot beam of sodium atoms crossing a thin slice of
resonant laser light within the magnetic field region to be investigated. The
inhomogeneous magnetic field spatially modulates the resonance condition
between the Zeeman-shifted hyperfine sublevels and the laser light and
therefore the amount of scattered photons. We demonstrate this technique by
mapping the field of our cloverleaf trap in three dimensions under various
conditions.Comment: 8 pages, 8 figure
Emergence of turbulence in an oscillating Bose-Einstein condensate
We report on the experimental observation of vortices tangle in an atomic BEC
of Rb-87 atoms when an external oscillatory perturbation is introduced in the
trap. The vortices tangle configuration is a signature of the presence of a
turbulent regime in the cloud. We also show that this turbulent cloud has
suppression of the aspect ratio inversion typically observed in quantum
degenerate bosonic gases during free expansion. Instead, the cloud expands
keeping the ratio between their axis constant. Turbulence in atomic superfluids
may constitute an alternative system to investigate decay mechanisms as well as
to test fundamental theoretical aspects in this field.Comment: accepted for Phys. Rev. Let
Far infrared emitting plaster in knee osteoarthritis: a single blinded, randomised clinical trial.
Objective. Therapeutic approach of osteoarthritis (OA) still represents a challenge in clinical practice. The aim of the study is to assess the efficacy of far infrared (FIR) emitting plaster in the treatment of knee OA. Design. This is a randomized, single-blind, placebo-controlled, parallel group with equal randomization (1:1), clinical trial. Patients affected by knee OA were randomly allocated to 1 of 2 treatment groups, either placebo plaster or far infrared emitting plaster. Primary endpoint was to assess pain improvement from baseline to 1 months posttreatment in the visual analogue score (VAS). Secondary end point was to evaluate pain score after 1 week of treatment and to compare ultrasonographic findings after 1 month of treatment. Results. Each group comprised 30 (in the FIR group) and 30 (in the placebo group) completers. VAS scores of the placebo and the FIR group were significantly lower at 1 week post-treatment (95% confidence interval CI = -1.14 to 0.31; P<0.05) and at the end of the study (95% confidence interval CI = -2.57 to -0.89; P=0.01). Effect size was -0.43 after one week of treatment and -1.38 after one month of treatment. The mean decrease in VAS values was ≥20% in the FIR group. The number of patients from the FIR group with joint effusion was lower (40%) compared to baseline (80%), while no changes were seen among the placebo group. Conclusions. Far infrared emitting plaster could be considered an effective non-pharmacological choice for the therapeutic management of knee OA
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