928 research outputs found
Older Carers and Involvement in Research
This poster describes some of the experiences of six bereaved older carers (see co-authors) involvement in research activities following their participation in a research project funded by Macmillan Cancer Support: The older carers support needs research development projec
Renormalized Effective QCD Hamiltonian: Gluonic Sector
Extending previous QCD Hamiltonian studies, we present a new renormalization
procedure which generates an effective Hamiltonian for the gluon sector. The
formulation is in the Coulomb gauge where the QCD Hamiltonian is renormalizable
and the Gribov problem can be resolved. We utilize elements of the Glazek and
Wilson regularization method but now introduce a continuous cut-off procedure
which eliminates non-local counterterms. The effective Hamiltonian is then
derived to second order in the strong coupling constant. The resulting
renormalized Hamiltonian provides a realistic starting point for approximate
many-body calculations of hadronic properties for systems with explicit gluon
degrees of freedom.Comment: 25 pages, no figures, revte
Undergraduate Rehabilitation Education and Accreditation: The Importance of Being Persistent
This article presents an overview of undergraduate rehabilitation education (URE) and the movement toward accreditation. Tracing the history of URE from the earliest days of rehabilitation education programs up to the present, this review discusses the purposes of URE, traditional URE program curricula, where URE graduates have been (and are being) employed, and the relationship between UREs and graduate rehabilitation counseling programs. The article also explains the development of URE curriculum and program standards, the development of a registry of qualified URE programs, and the transition to accreditation of URE programs in the United States. The purposes of accreditation are described, along with the advantages that accreditation offers to URE programs, their students, and to persons with disabilities
The Vacuum in Light-Cone Field Theory
This is an overview of the problem of the vacuum in light-cone field theory,
stressing its close connection to other puzzles regarding light-cone
quantization. I explain the sense in which the light-cone vacuum is
``trivial,'' and describe a way of setting up a quantum field theory on null
planes so that it is equivalent to the usual equal-time formulation. This
construction is quite helpful in resolving the puzzling aspects of the
light-cone formalism. It furthermore allows the extraction of effective
Hamiltonians that incorporate vacuum physics, but that act in a Hilbert space
in which the vacuum state is simple. The discussion is fairly informal, and
focuses mainly on the conceptual issues. [Talk presented at {\sc Orbis
Scientiae 1996}, Miami Beach, FL, January 25--28, 1996. To appear in the
proceedings.]Comment: 20 pages, RevTeX, 4 Postscript figures. Minor typos correcte
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Photonic encryption : modeling and functional analysis of all optical logic.
With the build-out of large transport networks utilizing optical technologies, more and more capacity is being made available. Innovations in Dense Wave Division Multiplexing (DWDM) and the elimination of optical-electrical-optical conversions have brought on advances in communication speeds as we move into 10 Gigabit Ethernet and above. Of course, there is a need to encrypt data on these optical links as the data traverses public and private network backbones. Unfortunately, as the communications infrastructure becomes increasingly optical, advances in encryption (done electronically) have failed to keep up. This project examines the use of optical logic for implementing encryption in the photonic domain to achieve the requisite encryption rates. This paper documents the innovations and advances of work first detailed in 'Photonic Encryption using All Optical Logic,' [1]. A discussion of underlying concepts can be found in SAND2003-4474. In order to realize photonic encryption designs, technology developed for electrical logic circuits must be translated to the photonic regime. This paper examines S-SEED devices and how discrete logic elements can be interconnected and cascaded to form an optical circuit. Because there is no known software that can model these devices at a circuit level, the functionality of S-SEED devices in an optical circuit was modeled in PSpice. PSpice allows modeling of the macro characteristics of the devices in context of a logic element as opposed to device level computational modeling. By representing light intensity as voltage, 'black box' models are generated that accurately represent the intensity response and logic levels in both technologies. By modeling the behavior at the systems level, one can incorporate systems design tools and a simulation environment to aid in the overall functional design. Each black box model takes certain parameters (reflectance, intensity, input response), and models the optical ripple and time delay characteristics. These 'black box' models are interconnected and cascaded in an encrypting/scrambling algorithm based on a study of candidate encryption algorithms. Demonstration circuits show how these logic elements can be used to form NAND, NOR, and XOR functions. This paper also presents functional analysis of a serial, low gate count demonstration algorithm suitable for scrambling/encryption using S-SEED devices
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Data encryption standard ASIC design and development report.
This document describes the design, fabrication, and testing of the SNL Data Encryption Standard (DES) ASIC. This device was fabricated in Sandia's Microelectronics Development Laboratory using 0.6 {micro}m CMOS technology. The SNL DES ASIC was modeled using VHDL, then simulated, and synthesized using Synopsys, Inc. software and finally IC layout was performed using Compass Design Automation's CAE tools. IC testing was performed by Sandia's Microelectronic Validation Department using a HP 82000 computer aided test system. The device is a single integrated circuit, pipelined realization of DES encryption and decryption capable of throughputs greater than 6.5 Gb/s. Several enhancements accommodate ATM or IP network operation and performance scaling. This design is the latest step in the evolution of DES modules
Quantum Mechanics of Dynamical Zero Mode in on the Light-Cone
Motivated by the work of Kalloniatis, Pauli and Pinsky, we consider the
theory of light-cone quantized on a spatial circle with periodic
and anti-periodic boundary conditions on the gluon and quark fields
respectively. This approach is based on Discretized Light-Cone Quantization
(DLCQ). We investigate the canonical structures of the theory. We show that the
traditional light-cone gauge is not available and the zero mode (ZM)
is a dynamical field, which might contribute to the vacuum structure
nontrivially. We construct the full ground state of the system and obtain the
Schr\"{o}dinger equation for ZM in a certain approximation. The results
obtained here are compared to those of Kalloniatis et al. in a specific
coupling region.Comment: 19 pages, LaTeX file, no figure
Sterol 3β-glucosyltransferase biocatalysts with a range of selectivities, including selectivity for testosterone
The main objectives of this work were to characterise a range of purified recombinant sterol 3β-glucosyltransferases and show that rational sampling of the diversity that exists within sterol 3β-glucosyltransferase sequence space can result in a range of enzyme selectivities. In our study the catalytically active domain of the Saccharomyces cerevisiae 3β-glucosyltransferase was used to mine putative sterol 3β-glucosyltransferases from the databases. Selected diverse sequences were expressed in and purified from Escherichia coli and shown to have different selectivities for the 3β-hydroxysteroids ergosterol and cholesterol. Surprisingly, three enzymes were also selective for testosterone, a 17β-hydroxysteroid. This study therefore reports for the first time sterol 3β-glucosyltransferases with selectivity for both 3β- and 17β-hydroxysteroids and is also the first report of recombinant 3β-glucosyltransferases with selectivity for steroids with a hydroxyl group at positions other than C-3. These enzymes could therefore find utility in the pharmaceutical industry for the green synthesis of a range of glycosylated compounds of medicinal interest
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