3,940 research outputs found

    Model of the optical emission of a driven semiconductor quantum dot: phonon-enhanced coherent scattering and off-resonant sideband narrowing

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    We study the crucial role played by the solid-state environment in determining the photon emission characteristics of a driven quantum dot. For resonant driving, we predict a phonon-enhancement of the coherently emitted radiation field with increasing driving strength, in stark contrast to the conventional expectation of a rapidly decreasing fraction of coherent emission with stronger driving. This surprising behaviour results from thermalisation of the dot with respect to the phonon bath, and leads to a nonstandard regime of resonance fluorescence in which significant coherent scattering and the Mollow triplet coexist. Off-resonance, we show that despite the phonon influence, narrowing of dot spectral sideband widths can occur in certain regimes, consistent with an experimental trend.Comment: Published version. 5 pages, 2 figures, plus 4 page supplement. Title changed, figure 1 revised, various edits and additions to the tex

    Determinants of Central bank independence and governance : problems and policy implications

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    Central bank independence and governance (CBIG) is a term subject to conflicting definitions and so its related studies are difficult to compare. This paper therefore focuses on developing of a more useable definition, and an index model identifying the determinants of independence and governance and their possible policy implications. It also examines various independence measurement tools such as ranking and index. The index model resulting centres on key central bank independence and corporate governance issues, such as, legal aspects, political aspects, price stability objective aspects, exchange rate policy aspects, monetary policy and deficit financing aspects and finally, transparency and accountability aspects.<br /

    A critical analysis of central bank independence and governance in Australia and Bangladesh

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    This study examines central bank independence and governance (CBIG) in Bangladesh and Australia. It applies a unique index model of Ahsan, Skully and Wickramanayake (2008) to assess their respective legal, political, price stability objectives, exchange rate policies, monetary policy and deficit financing practices, transparency and accountability positions from 1991 to 2008. While the model shows CBIG is much weaker in Bangladesh than in Australia, the Bangladesh Bank&rsquo;s CBIG shown considerable improvement over the period. These findings suggest that the Government of Bangladesh might learn from Australia&rsquo;s experience with Reserve Bank of Australia and delegate further power and authority to Bangladesh Bank as well as lessen its political interference.<br /

    Prototype system development for wireless vehicle speed monitoring

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    Vehicle speed monitoring and management of the associated data in an intelligent and efficient way is an important issue in modern transportation system in order to reduce road accidents. The aim of this work is to develop an automatic wireless system for monitoring vehicle speed on the road, identify a speeding vehicle and imposing penalty for the speeding offenders. In this work, a prototype system has been developed in a laboratory environment to generate random speed data using a mechanical wheel, measure the speed data with a Shimmer wireless sensor and transfer the data wirelessly to a client computer for further analysis. Software has been developed using a Java based socket programming technique to monitor the vehicle speed in a server computer and to send the data associated with a speeding vehicle to a remotely placed client computer. The graphical user interface (GUI) can visually display the speed of a vehicle at any particular time. The functionality of the software has been tested by simulating different traffic scenarios with low and high speed limits (40 and 60 km/hr respectively). To do that a high or low speed limit can be set in the GUI. The mechanical wheel is run at different speeds and the GUI continuously displays the speed. If the vehicle speed is higher than the set speed limit for the road, the system automatically detects it and generates a report with the time of speeding, vehicle number, vehicle speed etc. to be saved in the client computer in order to take further necessary actions for the speeding offender

    Optimization along families of periodic and quasiperiodic orbits in dynamical systems with delay

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    This is the final version. Available on open access from Springer Verlag via the DOI in this recordThis paper generalizes a previously-conceived, continuation-based optimization technique for scalar objective functions on constraint manifolds to cases of periodic and quasiperiodic solutions of delay-differential equations. A Lagrange formalism is used to construct adjoint conditions that are linear and homogenous in the unknown Lagrange multipliers. As a consequence, it is shown how critical points on the constraint manifold can be found through several stages of continuation along a sequence of connected one-dimensional manifolds of solutions to increasing subsets of the necessary optimality conditions. Due to the presence of delayed and advanced arguments in the original and adjoint differential equations, care must be taken to determine the degree of smoothness of the Lagrange multipliers with respect to time. Such considerations naturally lead to a formulation in terms of multi-segment boundary-value problems (BVPs), including the possibility that the number of segments may change, or that their order may permute, during continuation. The methodology is illustrated using the software package coco on periodic orbits of both linear and nonlinear delay-differential equations, keeping in mind that closed-form solutions are not typically available even in the linear case. Finally, we demonstrate optimization on a family of quasiperiodic invariant tori in an example unfolding of a Hopf bifurcation with delay and parametric forcing. The quasiperiodic case is a further original contribution to the literature on optimization constrained by partial differential BVPs.Engineering and Physical Sciences Research Council (EPSRC)European Union Horizon 202

    Wind-engineering study of Seattle Hotel, Seattle

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    CER78-79JEC-JAP-AK13.Prepared for John Graham and Company.Includes bibliographical references (pages 32-33).September 1978

    Human growth hormone alters carbohydrate storage in blood and liver in both genders of an Indian bird, Acridotheres tristis (Linn.)

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    Background: Growth hormone (GH) is a peptide hormone that plays vital roles in cell growth and metabolism. Aim: The study investigates the effect of GH on carbohydrate metabolism using Indian bird, Acridotheres tristis. Methods: Three different doses (0.4, 0.6, and 0.8mg/100g body weight) of human growth hormone (HGH) given once to both genders of a bird Acridotheres tristis to observe the effect on blood glucose and hepatic glycogen content in the body. Glucose and glycogen were quantitatively assayed. Results: Their effect was recorded for different time intervals (1, 4, 12, 24, 72, 96, and 144 h). Hypoglycaemic condition was recorded within an hour of hormone treatment in male and female birds. The lowest dose (0.4mg/100g body weight) was more effective than other two doses. Simultaneous depletion of hepatic glycogen was also recorded, although initially increase in glycogen level was also noticed in both genders. It was noticed that the highest dose (0.8mg/100g body weight) was most responsive. Conclusion: The effect of human growth hormone was not dose and time dependent in both male and female birds. HGH is thus hypoglycaemic and hepatic glycogenolytic in nature in A. tristis.Key words: Human growth hormone, blood glucose, hepatic glycogen, hypoglycaemia, glycogenolysis, bir

    Wind-tunnel study of block 259 building, Houston

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    CER78-79JEC-JAP-AK18.Prepared for Colaco Engineers, Inc.Includes bibliographical references (pages 32-33).January 1979
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