15,031 research outputs found
Time Delay Induced Death in Coupled Limit Cycle Oscillators
We investigate the dynamical behaviour of two limit cycle oscillators that
interact with each other via time delayed coupling and find that time delay can
lead to amplitude death of the oscillators even if they have the same
frequency. We demonstrate that this novel regime of amplitude "death" also
exists for large collections of coupled identical oscillators and provide
quantitative measures of this death region in the parameter space of coupling
strength and time delay. Its implication for certain biological and physical
applications is also pointed out.Comment: 4 aps formatted revtex pages; 3 figures; to be published in Phys.
Rev. Let
Simulation of electron transport in quantum well devices
Double barrier resonant tunneling diodes (DBRTD) have received much attention as possible terahertz devices. Despite impressive experimental results, the specifics of the device physics (i.e., how the electrons propagate through the structure) are only qualitatively understood. Therefore, better transport models are warranted if this technology is to mature. In this paper, the Lattice Wigner function is used to explain the important transport issues associated with DBRTD device behavior
Experimental Evidence of Time Delay Induced Death in Coupled Limit Cycle Oscillators
Experimental observations of time delay induced amplitude death in a pair of
coupled nonlinear electronic circuits that are individually capable of
exhibiting limit cycle oscillations are described. In particular, the existence
of multiply connected death islands in the parameter space of the coupling
strength and the time delay parameter for coupled identical oscillators is
established. The existence of such regions was predicted earlier on theoretical
grounds in [Phys. Rev. Lett. 80, 5109 (1998); Physica 129D, 15 (1999)]. The
experiments also reveal the occurrence of multiple frequency states, frequency
suppression of oscillations with increased time delay and the onset of both
in-phase and anti-phase collective oscillations.Comment: 4 aps formatted RevTeX pages; 6 figures; to appear in Phys. Rev. Let
Improving B-cell depletion in systemic lupus erythematosus and rheumatoid arthritis
INTRODUCTION: Rituximab-based B-cell depletion (BCD) therapy is effective in refractory rheumatoid arthritis (RA) and although used to treat patients with refractory systemic lupus erythematosus (SLE) in routine clinical practice, rituximab failed to meet the primary endpoints in two large randomised controlled trials (RCTs) of non-renal (EXPLORER) and renal (LUNAR) SLE. Areas covered: We review how BCD could be improved to achieve better clinical responses in RA and SLE. Insights into the variability in clinical response to BCD in RA and SLE may help develop new therapeutic strategies. To this end, a literature search was performed using the following terms: rheumatoid arthritis, systemic erythematosus lupus, rituximab and B-cell depletion. Expert commentary: Poor trial design may have, at least partly, contributed to the apparent lack of response to BCD in the two RCTs of patients with SLE. Enhanced B-cell depletion and/or sequential therapy with belimumab may improve clinical response at least in some patients with SLE
Meissner screening mass in two-flavor quark matter at nonzero temperature
We calculate the Meissner screening mass of gluons 4--7 in two-flavor quark
matter at nonzero temperature. To this end, we study the effective potential of
the 2SC/g2SC phases including a vector condensate . We find
that the Meissner mass becomes real at the critical temperature which is about
the half of the chemical potential mismatch. The phase diagram of the neutral
two-flavor color superconductor is presented in the plane of temperature and
coupling strength. We indicate the unstable region for gluons 4--7 on the phase
diagram.Comment: 4 pages, 3 figures, minor revisions to text, version to appear in PR
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