Nystr\"om methods for high-order CQ solutions of the wave equation in two dimensions

We investigate high-order Convolution Quadratures methods for the solution of the wave equation in unbounded domains in two dimensions that rely on Nystr\"om discretizations for the solution of the ensemble of associated Laplace domain modified Helmholtz problems. We consider two classes of CQ discretizations, one based on linear multistep methods and the other based on Runge-Kutta methods, in conjunction with Nystr\"om discretizations based on Alpert and QBX quadratures of Boundary Integral Equation (BIE) formulations of the Laplace domain Helmholtz problems with complex wavenumbers. We present a variety of accuracy tests that showcase the high-order in time convergence (up to and including fifth order) that the Nystr\"om CQ discretizations are capable of delivering for a variety of two dimensional scatterers and types of boundary conditions

The Chiral Fermion Meson Model at Finite Temperature

We study the chiral fermion meson model which is the well known linear sigma model of Gell-Mann-and-Levy at finite temperature.A modified self-consistent resummation (MSCR) which resums higher order terms in the perturbative expansion is proposed. It is shown that with the MSCR the problem of tachyonic masses is solved, the renormalization of the gap equations is carried out and the Goldstone's theorem is verified. We also apply the method to investigate another known case at high temperature and compare with results found in the literature.Comment: 31 pages, 9 EPS figures. Final version with extended Concluding Remarks section, accepted for publication in Phys. Rev.

Cell-Cell Transmission Enables HIV-1 to Evade Inhibition by Potent CD4bs Directed Antibodies

HIV is known to spread efficiently both in a cell-free state and from cell to cell, however the relative importance of the cell-cell transmission mode in natural infection has not yet been resolved. Likewise to what extent cell-cell transmission is vulnerable to inhibition by neutralizing antibodies and entry inhibitors remains to be determined. Here we report on neutralizing antibody activity during cell-cell transmission using specifically tailored experimental strategies which enable unambiguous discrimination between the two transmission routes. We demonstrate that the activity of neutralizing monoclonal antibodies (mAbs) and entry inhibitors during cell-cell transmission varies depending on their mode of action. While gp41 directed agents remain active, CD4 binding site (CD4bs) directed inhibitors, including the potent neutralizing mAb VRC01, dramatically lose potency during cell-cell transmission. This implies that CD4bs mAbs act preferentially through blocking free virus transmission, while still allowing HIV to spread through cell-cell contacts. Thus providing a plausible explanation for how HIV maintains infectivity and rapidly escapes potent and broadly active CD4bs directed antibody responses in vivo

Fast and broadband fibre dispersion measurement with dense wavelength sampling

We report on a method to obtain accurate dispersion measurements from low-coherence interferograms. This novel phase extraction method enables high accuracy, broadband measurements and very dense (20points/nm over 500nm) datasets for both dispersion and dispersion slope

Experimental Comparison of Gain and Saturation Characteristics of a Parametric Amplifier in Phase-sensitive and Phase-insensitive Mode

We demonstrate a parametric amplifier with precise control of the in-going waves and study gain and saturation properties in both PSA and PIA mode. A PSA gain of 33 dB is achieved

Experimental Comparison of Gain and Saturation Characteristics of a Parametric Amplifier in Phase-sensitive and Phase-insensitive Mode

We demonstrate a parametric amplifier with precise control of the in-going waves and study gain and saturation properties in both PSA and PIA mode. A PSA gain of 33 dB is achieved

Future Directions to Realize Ultra-High Bit-Rate Transmission Systems

In this paper we examine two potential future directions for the realization of ultra-high bit rate transmission systems

Future Directions to Realize Ultra-High Bit-Rate Transmission Systems

In this paper we examine two potential future directions for the realization of ultra-high bit rate transmission systems