Application of special-purpose digital computers to rotorcraft real-time simulation

The use of an array processor as a computational element in rotorcraft real-time simulation is studied. A multilooping scheme was considered in which the rotor would loop over its calculations a number of time while the remainder of the model cycled once on a host computer. To prove that such a method would realistically simulate rotorcraft, a FORTRAN program was constructed to emulate a typical host-array processor computing configuration. The multilooping of an expanded rotor model, which included appropriate kinematic equations, resulted in an accurate and stable simulation

Many-Body Rate Limit on Photoassociation of a Bose-Einstein Condensate

We briefly report on zero-temperature photoassociation of a Bose-Einstein condensate, focusing on the many-body rate limit for atom-molecule conversion. An upgraded model that explicitly includes spontaneous radiative decay leads to an unanticipated shift in the position of the photoassociation resonance, which affects whether the rate (constant) maximizes or saturates, as well as the limiting value itself. A simple analytical model agrees with numerical experiments, but only for high density. Finally, an explicit comparison with the two-body unitary limit, set by the size of the condensate, finds that the many-body rate limit is generally more strict.Comment: 4 pages, 3 figures, 59 references. v2: discussion added; to appear in PR

A real-time, dual processor simulation of the rotor system research aircraft

A real-time, man-in-the loop, simulation of the rotor system research aircraft (RSRA) was conducted. The unique feature of this simulation was that two digital computers were used in parallel to solve the equations of the RSRA mathematical model. The design, development, and implementation of the simulation are documented. Program validation was discussed, and examples of data recordings are given. This simulation provided an important research tool for the RSRA project in terms of safe and cost-effective design analysis. In addition, valuable knowledge concerning parallel processing and a powerful simulation hardware and software system was gained

System Design, User Cost and Electronic Usage of Journals

Dramatic increases in the capabilities and decreases in the costs of computers and communication networks have fomented revolutionary thoughts in the scholarly publishing community. In one dimension, traditional pricing schemes and product packages are being modified or replaced. We designed and undertook a large-scale field experiment in pricing and bundling for electronic access to scholarly journals: PEAK. We provided Internet-based delivery of content from 1200 Elsevier Science journals to users at multiple campuses and commercial facilities. Our primary research objective was to generate rich empirical evidence on user behavior when faced with various bundling schemes and price structures. In this article we explain the different types and levels of cost that users faced when accessing individual articles, and report on the effect of these costs on usage. We found that both monetary and non-monetary user costs have a significant impact on the demand for electronic access. We also estimate how taking user costs into account would change the optimal (least cost) bundle of access options that an institution should purchase.

To identify the incidence, severity and timing of hypophosphataemia in Glasgow Royal Infirmary Intensive Care Unit (ICU) [poster]

No abstract available

Theory of Combined Photoassociation and Feshbach Resonances in a Bose-Einstein Condensate

We model combined photoassociation and Feshbach resonances in a Bose-Einstein condensate, where the shared dissociation continuum allows for quantum interference in losses from the condensate, as well as a dispersive-like shift of resonance. A simple analytical model, based on the limit of weakly bound molecules, agrees well with numerical experiments that explicitly include dissociation to noncondensate modes. For a resonant laser and an off-resonant magnetic field, constructive interference enables saturation of the photoassociation rate at user-friendly intensities, at a value set by the interparticle distance. This rate limit is larger for smaller condensate densities and, near the Feshbach resonance, approaches the rate limit for magnetoassociation alone. Also, we find agreement with the unitary limit--set by the condensate size--only for a limited range of near-resonant magnetic fields. Finally, for a resonant magnetic field and an off-resonant laser, magnetoassociation displays similar quantum interference and a dispersive-like shift. Unlike photoassociation, interference and the fieldshift in resonant magnetoassociation is tunable with both laser intensity and detuning. Also, the dispersive-like shift of the Feshbach resonance depends on the size of the Feshbach molecule, and is a signature of non-universal physics in a strongly interacting system.Comment: 10 pages, 5 figures, 82 reference

In vivo and in vitro models of demyelinating diseases. V. Comparison of the assembly of mouse hepatitis virus, strain JHM, in two murine cell lines.

The developmental sequence of a neurotropic strain (JHM) of mouse hepatitis virus was examined by transmission electron microscopy and immunocytology. The nucleoprotein core of this coronavirus, which contains RNA of positive polarity and is helical in configuration, becomes incorporated into enveloped particles in the same manner as the nucleocapsids of the orthomyxo- and paramyxoviruses. However, JHM virus is assembled intracellularly by budding at surfaces of smooth membranous vacuoles. A comparison of JHM virus replication in L2 and 17Cl-1 cell lines revealed that L2 cells undergo more rapid cytopathology and cease virus production much sooner than 17Cl-l cells. In L2 cells the accumulation of core material appears to continue after the abrupt cessation of virus assembly. This is evident by the massive cytoplasmic accumulation of structure resembling nucleocapsids, which react with hybridoma antibody to the nucleocapsid antigen as demonstrated by the immunoperoxidase procedure. The current findings are consistent with our previously published demonstration, using cells of neural and other deviation, of the fundamental role of the host cell type in regulating the replication and expression of coronaviruses

Patients with Essential thrombocythaemia have an increased prevalence of antiphospholipid antibodies which may be associated with thrombosis

A significant proportion of patients with Essential Thrombocythaemia (ET) have thrombotic complications which have an important impact upon the quality, and duration of their life. We performed a retrospective cross sectional study of the prevalence of antiphospholipid antibodies (APA) in 68 ET patients. Compared to 200 elderly controls (> 50 years) there was a significant increase in anticardiolipin IgM (p < 0.0001) and anti β2 glycoprotein I (anti-β2GPI) IgM (p < 0.0001) antibodies in ET. Thrombosis occurred in 10/20 with APA and 12/48 without, p = 0.04, relative risk 2.0 (95% confidence intervals 1.03-3.86); these patients did not differ in terms of other clinical features. The prevalence of thrombosis in patients with dual APA (6/7) was significant when compared to those with single APA (p = 0.02) and the remaining patients (p < 0.0002). Also anti-β2GPI IgM antibodies either alone, or in combination with another APA, were associated with thrombosis (p = 0.02). These results suggest that the prevalence of APA in ET and their influence upon thrombotic risk merit investigation in a larger study

Pricing and Bundling Electronic Information Goods: Field Evidence

Dramatic increases in the capabilities and decreases in the costs of computers and communication networks have fomented revolutionary thoughts in the scholarly publishing community. In one dimension, traditional pricing schemes and product packages are being modified or replaced. We designed and undertook a large-scale field experiment in pricing and bundling for electronic access to scholarly journals: PEAK. We provided Internet-based delivery of content from 1200 Elsevier Science journals to users at multiple campuses and commercial facilities. Our primary research objective was to generate rich empirical evidence on user behavior when faced with various bundling schemes and price structures. In this article we report initial results. We found that although there is a steep initial learning curve, decision-makers rapidly comprehended our innovative pricing schemes. We also found that our novel and flexible "generalized subscription" was successful at balancing paid usage with easy access to a larger body of content than was previously available to participating institutions. Finally, we found that both monetary and non-monetary user costs have a significant impact on the demand for electronic access.

The incidence, severity, timing and circadian variation of hypophosphataemia in Glasgow Royal Infirmary Intensive Care Unit [poster]

No abstract available