9,752 research outputs found

    Currency preferences and the Australian dollar

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    We investigate the theory and empirics of currency substitution and currency complementarity. Analytical tractability is facilitated by focussing on a small currency. Data spanning 1985 to the turn of the century contain evidence of the Australian dollar’s substitution for the mark and complementarity with the yen, consistent with our theory that international variables will in general affect the demand for domestic money. Our theory also predicts third-currency effects, and the data reveal several of these. For example, rises in the US Federal Funds rate were associated with depreciations of the Australian dollar against the yen, controlling for the spread between interest rates in Australia and Japan.Atemporally non-separable preferences; Money demand; Cash in advance; Third-currency effects; Uncovered Interest Parity

    Stable isotope fractionation during ultraviolet photolysis of N_2O

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    The biogeochemical cycling of nitrous oxide plays an important role in greenhouse forcing and ozone regulation. Laboratory studies of N_2O:N_2 mixtures irradiated between 193–207 nm reveal a significant enrichment of the residual heavy nitrous oxide isotopomers. The isotopic signatures resulting from photolysis are well modeled by an irreversible Rayleigh distillation process, with large enrichment factors of ε_(15,18)(193 nm) = −18.4,‐14.5 per mil and ε_(15,18)(207 nm) = −48.7,‐46.0 per mil. These results, when combined with diffusive mixing processes, have the potential to explain the stratospheric enrichments previously observed

    Inherent work suit buoyancy distribution:effects on lifejacket self-righting performance

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    Introduction: Accidental immersion in cold water is an occupational risk. Work suits and life jackets (LJ) should work effectively in combination to keep the airway clear of the water (freeboard) and enable self-righting. We hypothesized that inherent buoyancy, in the suit or LJ, would be beneficial for enabling freeboard, but its distribution may influence LJ self-righting. Methods: Six participants consented to complete nine immersions. Suits and LJ tested were: flotation suit (FLOAT; 85 N inherent buoyancy); oilskins 1 (OS-1) and 2 (OS-2), both with no inherent buoyancy; LJs (inherent buoyancy/buoyancy after inflation/total buoyancy), LJ-1 50/150/200 N, LJ-2 0/290/290 N, LJ-3 80/190/270 N. Once dressed, the subject entered an immersion pool where uninflated freeboard, self-righting performance, and inflated freeboard were measured. Data were compared using Friedman’s test to the 0.05 alpha level. Results: All suits and LJs enabled uninflated and inflated freeboard, but differences were seen between the suits and LJs. Self-righting was achieved on 43 of 54 occasions, irrespective of suit or LJ. On all occasions that self-righting was not achieved, this occurred in an LJ that included inherent buoyancy (11/54 occasions). Of these 11 failures, 8 occurred (73% of occasions) when the FLOAT suit was being worn. Discussion: LJs that included inherent buoyancy, that are certified as effective on their own, worked less effectively from the perspective of self-righting in combination with a work suit that also included inherent buoyancy. Equipment that is approved for use in the workplace should be tested in combination to ensure adequate performance in an emergency scenario

    The geometry of kernelized spectral clustering

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    Clustering of data sets is a standard problem in many areas of science and engineering. The method of spectral clustering is based on embedding the data set using a kernel function, and using the top eigenvectors of the normalized Laplacian to recover the connected components. We study the performance of spectral clustering in recovering the latent labels of i.i.d. samples from a finite mixture of nonparametric distributions. The difficulty of this label recovery problem depends on the overlap between mixture components and how easily a mixture component is divided into two nonoverlapping components. When the overlap is small compared to the indivisibility of the mixture components, the principal eigenspace of the population-level normalized Laplacian operator is approximately spanned by the square-root kernelized component densities. In the finite sample setting, and under the same assumption, embedded samples from different components are approximately orthogonal with high probability when the sample size is large. As a corollary we control the fraction of samples mislabeled by spectral clustering under finite mixtures with nonparametric components.Comment: Published at http://dx.doi.org/10.1214/14-AOS1283 in the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org

    UK air-sea integration in Libya, 2011: a successful blueprint for the future?

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    This is an English version of the chapter written in March 2012 and which appeared in ‘Integration der britischen Luft- und Seestreitkräfte im Libyenkrieg 2011: Erfolgreiche Blaupause für die Zukunft?’ in S. Bruns, K. Petretto, D. Petrovic (eds), Maritime Sicherheit, Globale Gesellschaft und internationale Beziehungen, (VS-Verlag, Wiesbaden, 2013), ISBN: 978-3-531-18479-1. The Corbett Centre would like to thank the publishers for permission to reproduce it as a Corbett Paper.Libya was a successful operation fought in a manner Sir Julian Corbett would have immediately recognised as being typically British. Operational success was based upon the successful integration of UK air and sea assets. As a time, scope and geographically limited operation based on air and sea integration as part of an existing alliance framework (NATO), UK participation in the 2011 Libya operation seems likely to help set the course for British defence in the short-term. Sea based forces were crucial to ensure sea control as an enabler for projecting force ashore from the sea through TLAM and NGS and carrier based aviation. They also enforced a UN arms embargo on the Libyan regime while allowing supplies to reach the Libyan rebel forces

    Switches and mortar in the Internet's shadow : a study of the effects of technology on competitive strategy for the Internet's landlords

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    Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Architecture, 2000.Includes bibliographical references (leaves 132-138).Communications technology has experienced a period of explosive growth, driven by a confluence of legal, political and technical factors including the following: the 1968 Carter Phone and 1980's competitive carrier decisions, the 1984 divestiture of AT&T, the Telecommunications Act of 1996, the development and standardization of new technologies, and the proliferation of the Internet and World Wide Web. This thesis asks the fundamental questions: How has the rapid growth of the Internet and other communications technologies changed the competitive strategy of commercial tenants, and how have these changes affected commercial real estate developers? This study proposes that developers and landlords need to use more forward-looking theories of competitive strategy in order to understand the current and future real estate needs of technology-driven commercial tenants. Telecommunications deregulation and the growth of the Internet led to the creation of a new and rapidly growing high technology industry and commercial tenancy. Deregulation and the Internet also transformed the way traditional commercial real estate uses information technology, encouraged the forging of partnerships between commercial real estate professionals and "last mile" information technology contractors, and resulted in the creation of a new commercial real estate product-the telecom hotel.' Current literature suggests traditional commercial tenants might differ from Internet-based business tenants in four general areas of the development process: feasibility, site selection, design and building operations. The proliferation of the Internet as a catalyst for new real estate products, commercial tenants and partnerships, and the observed differences in development practices between traditional and commercial tenants are both clues to fundamental differences between these two tenants' competitive strategies. It is possible to understand these clues to tenant behavior by taking an in-depth look at how these two tenants compete in their respective industries. Traditional commercial business tenants appear to conform to Michael Porter's theories on competitive strategy and advantage. High-tech tenant's competitive strategies seem to be more accurately reflected by Gary Hamel and C.K. Prahalad's model of competition for the future. These two theories, and the industries they represent, differ in four dimensions: Future versus Past/Present orientation, technology use, rate of growth, and resource use. In comparing three case studies on these four strategic dimensions, this thesis concludes that Porter's more stable, efficiency-oriented model does explain the strategy of Northwestern Mutual, a large insurance organization. Hamel and Prahalad's model better explains the hectic, high growth, future orientation of Akamai and YankeeTek Incubator as well as Teleplace, a telecom hotel service company. Hamel and Prahalad and Porter's frameworks explain significant discrepancies between predicted development practices based on current industry thinking, and observed development practices based on these in depth case studies. This thesis thus verifies a need by real estate developers and landlords to use forward-looking theories of competitive strategy when examining the current and future needs of hightech tenants.by Geoffrey Morgan and Benjamin V.A. Pettigrew.S.M

    British pain clinic practitioners' recognition and use of the bio-psychosocial pain management model for patients when physical interventions are ineffective or inappropriate : results of a qualitative study

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    Background To explore how chronic musculoskeletal pain is managed in multidisciplinary pain clinics for patients for whom physical interventions are inappropriate or ineffective. Methods A qualitative study was undertaken using semi-structured interviews with twenty five members of the pain management team drawn from seven pain clinics and one pain management unit located across the UK. Results All clinics reported using a multidisciplinary bio-psychosocial model. However the chronic pain management strategy actually focussed on psychological approaches in preference to physical approaches. These approaches were utilised by all practitioners irrespective of their discipline. Consideration of social elements such as access to social support networks to support patients in managing their chronic pain was conspicuously absent from the approaches used. Conclusion Pain clinic practitioners readily embraced cognitive/behavioural based management strategies but relatively little consideration to the impact social factors played in managing chronic pain was reported. Consequently multidisciplinary pain clinics espousing a bio-psychosocial model of pain management may not be achieving their maximum potential

    Thermal profiles within the channel of planar gunn diodes using micro-particle sensors

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    The paper describes the use of a novel microparticle sensor (~3 μm diameter) and infra-red (IR) microscopy to measure the temperature profile within the active channel (typically 3 μm length and 120 μm width) of planar Gunn diodes. The method has enabled detailed temperature measurements showing an asymmetrical temperature profile along the active width of these devices. The asymmetrical temperature profile suggests a similar behaviour in the channel current density, which may contribute to the lower than expected RF output power
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