4,982 research outputs found
Optical waveguide arrays: quantum effects and PT symmetry breaking
Over the last two decades, advances in fabrication have led to significant
progress in creating patterned heterostructures that support either carriers,
such as electrons or holes, with specific band structure or electromagnetic
waves with a given mode structure and dispersion. In this article, we review
the properties of light in coupled optical waveguides that support specific
energy spectra, with or without the effects of disorder, that are
well-described by a Hermitian tight-binding model. We show that with a
judicious choice of the initial wave packet, this system displays the
characteristics of a quantum particle, including transverse photonic transport
and localization, and that of a classical particle. We extend the analysis to
non-Hermitian, parity and time-reversal () symmetric Hamiltonians
which physically represent waveguide arrays with spatially separated, balanced
absorption or amplification. We show that coupled waveguides are an ideal
candidate to simulate -symmetric Hamiltonians and the transition
from a purely real energy spectrum to a spectrum with complex conjugate
eigenvalues that occurs in them.Comment: 16 pages, 12 figures, Invited Review for European Physics Journal -
Applied Physic
A second large plasmid encodes conjugative transfer and antimicrobial resistance in O119:H2 and some typical O111 enteropathogenic \u3ci\u3eEscherichia coli\u3c/i\u3e strains
A novel and functional conjugative transfer system identified in O119:H2 enteropathogenic Escherichia coli (EPEC) strain MB80 by subtractive hybridization is encoded on a large multidrug resistance plasmid, distinct from the well-described EPEC adherence factor (EAF) plasmid. Variants of the MB80 conjugative resistance plasmid were identified in other EPEC strains, including the prototypical O111:NM strain B171, from which the EAF plasmid has been sequenced. This separate large plasmid and the selective advantage that it confers in the antibiotic era have been overlooked because it comigrates with the virulence plasmid on conventional gels
Finitely generated soluble groups and their subgroups
We prove that every finitely generated soluble group which is not virtually
abelian has a subgroup of one of a small number of types.Comment: 16 page
Wisconsin Vietnam War Stories: Our Veterans Remember
Review of: "Wisconsin Vietnam War Stories: Our Veterans Remember," by Sarah A. Larsen and Jennifer M. Miller
Water in biopharmaceutical manufacturing
The use of water in biopharmaceutical manufacturing is tightly controlled and supremely important to the quality of the products. It is often the single most used raw material and the one that comes to mind last even in the most experience biopharmaceutical professionals. This presentation will explore the types of water, how they are generated, how they are used, and how water is disposed of in biopharmaceutical manufacturing processes
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