54,075 research outputs found

    Exploiting long-range disorder in slow-light photonic crystal waveguides

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    The interplay between order and disorder in photonic lattices opens up a wide range of novel optical scattering mechanisms, resonances, and applications that can be obscured by typical ordered design approaches to photonics. Striking examples include Anderson localization, random lasers, and visible light scattering in biophotonic structures such as butterfly wings. In this work, we present a profound example of light localization in photonic crystal waveguides by introducing long-range correlated disorder. Using a rigorous three-dimensional Bloch mode expansion technique, we demonstrate how inter-hole correlations have a negative contribution to the total out-of-plane radiative losses, leading to a pronounced enhancement of the quality factor, QQ, and Q/VQ/V cavity figures of merit in the long-range correlation regime. Subsequently, the intensity fluctuations of the system are shown to globally increase with the correlation length, highlighting the non-trivial role of long-range disorder on the underlying scattering mechanisms. We also explore the possibility of creating ultra-high quality cavity modes via inter-hole correlations, which have various functionalities in chip-based nonlinear optics and waveguide cavity-quantum electrodynamics.Comment: Updated version with DO

    Girls on the move impact statement

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    Since 2005, Youth Scotland’s Girls on the Move programme has been increasing young women’s physical activity levels in Scotland, by addressing the barriers that prevent their participation. The programme has been evaluated by a team from the School of Sport at Stirling University, led by John Taylor, Research Fellow. This team, in partnership with Youth Scotland, has recently published an Impact Statement to summarise the findings of the evaluation. The Impact Statement contains facts, figures and case studies which the influence Girls on the Move has had on young women across Scotland

    Efficiency in banking: theory, practice, and evidence

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    Great strides have been made in the theory of bank technology in terms of explaining banks’ comparative advantage in producing informationally intensive assets and financial services and in diversifying or offsetting a variety of risks. Great strides have also been made in explaining sub-par managerial performance in terms of agency theory and in applying these theories to analyze the particular environment of banking. In recent years, the empirical modeling of bank technology and the measurement of bank performance have begun to incorporate these theoretical developments and yield interesting insights that reflect the unique nature and role of banking in modern economies. This paper gives an overview of two general empirical approaches to measuring bank performance and discusses some of the applications of these approaches found in the literature.Banks and banking - Research

    Nonthermal X-Ray Emission from G266.2-1.2 (RX J0852.0-4622)

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    The newly discovered supernova remnant G266.2-1.2 (RX J0852.0-4622), along the line of sight to the Vela SNR, was observed with ASCA for 120 ks. We find that the X-ray spectrum is featureless, and well described by a power law, extending to three the class of shell-type SNRs dominated by nonthermal X-ray emission. Although the presence of the Vela SNR compromises our ability to accurately determine the column density, the GIS data appear to indicate absorption considerably in excess of that for Vela itself, indicating that G266.2-1.2 may be several times more distant. An unresolved central source may be an associated neutron star, though difficulties with this interpretation persist.Comment: 4 pages, 5 figures, uses aipproc.sty & epsfig.sty. To appear in "Young Supernova Remnants" (11th Annual Astrophysics Conference in Maryland), S. S. Holt & U. Hwang (eds), AIP, New York (2001

    Who said large banks don't experience scale economies? Evidence from a risk-return-driven cost function

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    Earlier studies found little evidence of scale economies at large banks; later studies using data from the 1990s uncovered such evidence, providing a rationale for very large banks seen worldwide. Using more recent data, the authors estimate scale economies using two production models. The standard risk-neutral model finds little evidence of scale economies. The model using more general risk preferences and endogenous risk-taking finds large scale economies. The authors show that these economies are not driven by too-big-to-fail considerations. They evaluate the cost implications of breaking up the largest banks into banks of smaller size.Production (Economic theory) ; Risk ; Systemic risk ; Banks and banking

    TACAN operational description for the space shuttle orbital flight test program

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    The TACAN subsystems (three TACAN transponders, six antennas, a subsystem operating program, and redundancy management software in a tutorial form) are discussed and the interaction between these subsystems and the shuttle navigation system are identified. The use of TACAN during the first space transportation system (STS-1), is followed by a brief functional description of the TACAN hardware, then proceeds to cover the software units with a view to the STS-1, and ends with a discussion on the shuttle usage of the TACAN data and anticipated performance
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