6,129 research outputs found
Stable branching rules for classical symmetric pairs
We approach the problem of obtaining branching rules from the point of view
of dual reductive pairs. Specifically, we obtain a stable branching rule for
each of 10 classical families of symmetric pairs. In each case, the branching
multiplicities are expressed in terms of Littlewood-Richardson coefficients.
Some of the formulas are classical and include, for example, Littlewood's
restriction rule as a special case.Comment: 26 page
High mobility two-dimensional electron system on hydrogen-passivated silicon(111) surfaces
We have fabricated and characterized a field-effect transistor in which an
electric field is applied through an encapsulated vacuum cavity and induces a
two-dimensional electron system on a hydrogen-passivated Si(111) surface. This
vacuum cavity preserves the ambient sensitive surface and is created via room
temperature contact bonding of two Si substrates. Hall measurements are made on
the H-Si(111) surface prepared in aqueous ammonium fluoride solution. We obtain
electron densities up to cm and peak mobilities of
cm/V s at 4.2 K.Comment: to appear in Applied Physics Letter
Broadband Tuning (170nm) of InGaAs Quantum Well Lasers
The wavelength tuning properties of strained InGaAs quantum well lasers using an external grating for feedback is reported. Tunable laser oscillation has been observed over a range of 170 nm, between 840 and 1010 nm, under pulsed current excitation. The optimal conditions for broadband tunability for the InGaAs lasers are different from GaAs lasers, which is attributed to a difference in spectral gain curves. Together with an optimised GaAs quantum well laser the entire region between 740 and 1010 nm is spanned
Therapists\u27 use of the graded repetitive arm supplementary program (GRASP) intervention: A practice implementation survey study
The aims of this study were: (1) to explore the extent of practice implementation of GRASP in the United Kingdom; (2) using an implementation framework, to explore UK therapists\u27 opinions of implementing GRASP; and (3) if GRASP is found to be used in the United Kingdom, to investigate differences in opinions between therapists who are using GRASP in practice and those who are not
Sequence of Tissue Responses in the Early Stages of Experimental Allergic Encephalomyelitis (EAE): Immunohistochemical, Light Microscopic, and Ultrastructural Observations in the Spinal Cord
Experimental allergic encephalomyelitis (EAE) was induced in adult Lewis rats with purified guinea pig CNS myelin and Freund's adjuvant. As soon as the very earliest clinical signs appeared the animals were perfused with fixatives and the spinal cord analyzed by electron microscopy, silver methods, and immunocytochemistry. Our findings suggest that in the early stages of EAE a sequence of events can be traced, although these events frequently overlap. The earliest morphological change appears to be astrocytic edema in both the cell body and processes. Increased amounts of glycogen particles and dispersion of glial filaments are prominent. These changes seem to occur just prior to the time when inflammatory cells begin to penetrate the capillary walls. Invasion of the neuropil mainly by macrophages and lymphocytes closely follows. Both macrophages and microglia seem to participate in phagocytosis of oligodendrocytes and myelin. Demyelination, however, is not a prominent feature at this early stage
Design and Implementation of Discrete-event Simulation Framework for Modeling Bus Rapid Transit System
- …