Viscous damped space structure for reduced jitter

A technique to provide modal vibration damping in high performance space structures was developed which uses less than one once of incompressible fluid. Up to 50 percent damping can be achieved which can reduce the settling times of the lowest structural mode by as much as 50 to 1. This concept allows the designers to reduce the weight of the structure while improving its dynamic performance. Damping by this technique is purely viscous and has been shown by test to be linear over 5 orders of input magnitude. Amplitudes as low as 0.2 microinch were demonstrated. Damping in the system is independent of stiffness and relatively insensitive to temperature

Sheffield University CLEF 2000 submission - bilingual track: German to English

We investigated dictionary based cross language information retrieval using lexical triangulation. Lexical triangulation combines the results of different transitive translations. Transitive translation uses a pivot language to translate between two languages when no direct translation resource is available. We took German queries and translated then via Spanish, or Dutch into English. We compared the results of retrieval experiments using these queries, with other versions created by combining the transitive translations or created by direct translation. Direct dictionary translation of a query introduces considerable ambiguity that damages retrieval, an average precision 79% below monolingual in this research. Transitive translation introduces more ambiguity, giving results worse than 88% below direct translation. We have shown that lexical triangulation between two transitive translations can eliminate much of the additional ambiguity introduced by transitive translation

Immunofluorescent Examination of Biopsies from Long-Term Renal Allografts

Immunofluorescent examination of open renal biopsies revealed clear-cut glomerular localization of immunoglobulins not related clearly to the quality of donor-recipient histocompatibility in 19 of 34 renal allografts. The biopsies were obtained 18 to 31 months after transplantations primarily from related donors with a variable quality of histocompatibility match. IgG was the predominant immunoglobulin class fixed in 13 biopsies, and IgM in six. The pattern of immunoglobulin deposition was linear, connoting anti-GBM antibody in four of the 19; it was granular and discontinuous, connoting antigen–antibodycomplex deposits, in 13. An immune process may affect glomeruli of renal allografts by mechanisms comparable to those that cause glomerulonephritis in native kidneys. The transplant glomerulonephritis may represent a persistence of the same disease that originally destroyed the host kidneys or the consequence of a new humoral antibody response to allograft antigens. © 1970, Massachusetts Medical Society. All rights reserved

Inverse Compton Emission from Galactic Supernova Remnants: Effect of the Interstellar Radiation Field

The evidence for particle acceleration in supernova shells comes from electrons whose synchrotron emission is observed in radio and X-rays. Recent observations by the HESS instrument reveal that supernova remnants also emit TeV gamma-rays; long awaited experimental evidence that supernova remnants can accelerate cosmic rays up to the ``knee'' energies. Still, uncertainty exists whether these gamma-rays are produced by electrons via inverse Compton scattering or by protons via neutral pion decay. The multi-wavelength spectra of supernova remnants can be fitted with both mechanisms, although a preference is often given to neutral pion decay due to the spectral shape at very high energies. A recent study of the interstellar radiation field indicates that its energy density, especially in the inner Galaxy, is higher than previously thought. In this paper we evaluate the effect of the interstellar radiation field on the inverse Compton emission of electrons accelerated in a supernova remnant located at different distances from the Galactic Centre. We show that contribution of optical and infra-red photons to the inverse Compton emission may exceed the contribution of cosmic microwave background and in some cases broaden the resulted gamma-ray spectrum. Additionally, we show that if a supernova remnant is located close to the Galactic Centre its gamma-ray spectrum will exhibit a ``universal'' cutoff at very high energies due to the Klein-Nishina effect and not due to the cut-off of the electron spectrum. As an example, we apply our calculations to the supernova remnants RX J1713.7-3946 and G0.9+0.1 recently observed by HESS.Comment: 4 pages, 4 figures. Uses emulateapj.cls. Accepted by ApJ

Restrictions and Stability of Time-Delayed Dynamical Networks

This paper deals with the global stability of time-delayed dynamical networks. We show that for a time-delayed dynamical network with non-distributed delays the network and the corresponding non-delayed network are both either globally stable or unstable. We demonstrate that this may not be the case if the network's delays are distributed. The main tool in our analysis is a new procedure of dynamical network restrictions. This procedure is useful in that it allows for improved estimates of a dynamical network's global stability. Moreover, it is a computationally simpler and much more effective means of analyzing the stability of dynamical networks than the procedure of isospectral network expansions introduced in [Isospectral graph transformations, spectral equivalence, and global stability of dynamical networks. Nonlinearity, 25 (2012) 211-254]. The effectiveness of our approach is illustrated by applications to various classes of Cohen-Grossberg neural networks.Comment: 32 pages, 9 figure

Distribution of the spacing between two adjacent avoided crossings

We consider the frequency at which avoided crossings appear in an energy level structure when an external field is applied to a quantum chaotic system. The distribution of the spacing in the parameter between two adjacent avoided crossings is investigated. Using a random matrix model, we find that the distribution of these spacings is well fitted by a power-law distribution for small spacings. The powers are 2 and 3 for the Gaussian orthogonal ensemble and Gaussian unitary ensemble, respectively. We also find that the distributions decay exponentially for large spacings. The distributions in concrete quantum chaotic systems agree with those of the random matrix model.Comment: 11 page

Finite-difference distributions for the Ginibre ensemble

The Ginibre ensemble of complex random matrices is studied. The complex valued random variable of second difference of complex energy levels is defined. For the N=3 dimensional ensemble are calculated distributions of second difference, of real and imaginary parts of second difference, as well as of its radius and of its argument (angle). For the generic N-dimensional Ginibre ensemble an exact analytical formula for second difference's distribution is derived. The comparison with real valued random variable of second difference of adjacent real valued energy levels for Gaussian orthogonal, unitary, and symplectic, ensemble of random matrices as well as for Poisson ensemble is provided.Comment: 8 pages, a number of small changes in the tex

Trade and market in conflict development and conflict resolution in Nigeria: scoping study report to the UK department for International Development.

This study of trade related conflict and its resolution in Nigeria’s was prompted by the needs of policy makers concerned with improving market access for the poor. There is a lack of published material analysing links between trade/markets and conflict development/conflict resolution. The study is based on a literature review, a small number of interviews in Nigeria and UK and a one-day workshop:it was conceived as a pilot to identify areas for future research. The informality of Nigeria’s agricultural produce trade has the potential to promote both cooperation and conflict. The food marketing chains are complex networks extending across the country, and often involve diverse ethnic, religious and social groups. For the most part these linkages work extremely effectively, drawing on substantial inter-gender, inter-ethnic and inter-religious cooperation,often built up over generations.Nonetheless, there is potential for