17,872 research outputs found

    Random discrete groups of Möbius transformations : probabilities and limit set dimensions : a thesis presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Mathematics at Massey University, Albany, New Zealand

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    This thesis addresses two areas related to the quantification of discrete groups. We study "random" groups of Möbius transformations and in particular random two-generator groups; that is, groups where the generators are selected randomly. Our intention is to estimate the likelihood that such groups are discrete and to calculate the expectation of their associated geometric and topological parameters. Computational results of the author [55] that indicate a low probability of a random group being discrete are extended and we also assess the expected Hausdorff dimension of the limit set of a discrete group. In both areas of research analytic determinations are correlated with computational results. Our results depend on the precise notion of randomness and we introduce geometrically natural probability measures on the groups of all Möbius transformations of the circle and the Riemann sphere

    Art-making as a resource for the emergence of alternative personal and recovery narratives for people with an experience of psychosis

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    Dominant narratives about psychosis portray individuals as lonely, dangerous and unable to contribute to society. Such views may be incorporated into an individual’s personal story and are associated with negative outcomes for personal and clinical recovery. Art-making is associated with personal meaning-making and alternative forms of expression. It is therefore considered potentially relevant to narrative modification. Adult service-users with psychosis participated in a gallery-based art-making intervention. At interview, participants used their self-created images to help tell their story. Literary, experience-centred and culturally-oriented lenses were used to analyse narratives. Turning-points as modifiers of stigmatised dominant narratives were explored, as was how the intervention supported recovery. Art-making was associated with achievement, challenge and satisfaction. Story-telling using visual and verbal means opened up stories and alternative perspectives for participants. Recovery-principles including hope and aspiration were supported, identified through goals and recognition of achievement. Sharing experiences with others with similar experiences was viewed as impacting positively on mental-health. The intervention represented effective partnership working between NHS services and a gallery in overcoming barriers to accessing the arts, for people with psychosis. Achievements in art-making and narrating experience using visual and verbal means offered alternatives to personally limiting and illness-dominated narratives

    Introduction

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    The costs and benefits of European Imperialism from the conquest of Ceuta, 1415, to the Treaty of Lusaka, 1974.Twelfth International Economic History Congress. Madrid, 1998.Patrick K. O'Brien and Leandro Prados de la Escosura (eds.)Editada en la Fundación Empresa PúblicaPatrick K. O'Brien and Leandro Prados de la Escosura. The Costs and Benefits for Europeans from their Empires Overseas.Publicad

    Theories of Technological Progress and the British Textile Industry from Kay to Cartwright

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    Editada en la Fundación Empresa PúblicaLa industria textil británica continúa en el centro del debate sobre la revolución industrial. Las innovaciones técnicas en el período produjeron una aceleración extraordinaria del crecimiento del output y una considerable reducción de los precios de los tejidos. En este trabajo presentamos un estudio de la comunidad de los inventores responsables de la transformación tecnológica, lo que nos permite alcanzar una serie de conclusiones nuevas sobre el ritmo y dirección de la actividad innovadora durante la revolución industrialThe cotton textile industry remains central to all accounts of the first industrial revolution. Innovations in this period precipitated an extraordinary acceleration in the growth of output and a steep decline in the cost of producing all varieties of cloth. In this paper we outline an explanation through an analysis of the community of inventors responsible for the technological transformation, which enables us to offer some generalizations of the pace and pattern of the inventive activity in this period.Publicad

    Resolving the large scale spectral variability of the luminous Seyfert 1 galaxy 1H 0419-577: Evidence for a new emission component and absorption by cold dense matter

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    An XMM-Newton observation of the luminous Seyfert 1 galaxy 1H 0419-577 in September 2002, when the source was in an extreme low-flux state, found a very hard X-ray spectrum at 1-10 keV with a strong soft excess below ~1 keV. Comparison with an earlier XMM-Newton observation when 1H 0419-577 was `X-ray bright' indicated the dominant spectral variability was due to a steep power law or cool Comptonised thermal emission. Four further XMM-Newton observations, with 1H 0419-577 in intermediate flux states, now support that conclusion, while we also find the variable emission component in intermediate state difference spectra to be strongly modified by absorption in low ionisation matter. The variable `soft excess' then appears to be an artefact of absorption of the underlying continuum while the `core' soft emission can be attributed to recombination in an extended region of more highly ionised gas. We note the wider implications of finding substantial cold dense matter overlying (or embedded in) the X-ray continuum source in a luminous Seyfert 1 galaxy.Comment: 34 pages, 15 figures, submitted to Ap

    Correspondence: British Thoracic Society guideline on pulmonary rehabilitation in adults: Does objectivity have a sliding scale?

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    This article is made available through the Brunel Open Access Publishing Fund. Copyright © 2014 BMJ Publishing Group Ltd & British Thoracic Society. This is an Open Access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 3.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is noncommercial. See: http://creativecommons.org/licenses/ by-nc/3.0/No abstract available (Letter

    Improving wafer-scale Josephson junction resistance variation in superconducting quantum coherent circuits

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    Quantum bits, or qubits, are an example of coherent circuits envisioned for next-generation computers and detectors. A robust superconducting qubit with a coherent lifetime of OO(100 μ\mus) is the transmon: a Josephson junction functioning as a non-linear inductor shunted with a capacitor to form an anharmonic oscillator. In a complex device with many such transmons, precise control over each qubit frequency is often required, and thus variations of the junction area and tunnel barrier thickness must be sufficiently minimized to achieve optimal performance while avoiding spectral overlap between neighboring circuits. Simply transplanting our recipe optimized for single, stand-alone devices to wafer-scale (producing 64, 1x1 cm dies from a 150 mm wafer) initially resulted in global drifts in room-temperature tunneling resistance of ±\pm 30%. Inferring a critical current IcI_{\rm c} variation from this resistance distribution, we present an optimized process developed from a systematic 38 wafer study that results in << 3.5% relative standard deviation (RSD) in critical current (σIc/Ic\equiv \sigma_{I_{\rm c}}/\left\langle I_{\rm c} \right\rangle) for 3000 Josephson junctions (both single-junctions and asymmetric SQUIDs) across an area of 49 cm2^2. Looking within a 1x1 cm moving window across the substrate gives an estimate of the variation characteristic of a given qubit chip. Our best process, utilizing ultrasonically assisted development, uniform ashing, and dynamic oxidation has shown σIc/Ic\sigma_{I_{\rm c}}/\left\langle I_{\rm c} \right\rangle = 1.8% within 1x1 cm, on average, with a few 1x1 cm areas having σIc/Ic\sigma_{I_{\rm c}}/\left\langle I_{\rm c} \right\rangle << 1.0% (equivalent to σf/f\sigma_{f}/\left\langle f \right\rangle << 0.5%). Such stability would drastically improve the yield of multi-junction chips with strict critical current requirements.Comment: 10 pages, 4 figures. Revision includes supplementary materia

    Refugees on the High Seas: International Refugee Solutions to a Law of the Sea Problem

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    Following in the aftermath of the Arab Spring, Europe’s southern marine borders have been the showplace of human tragedies previously unseen on this scale and the issue of refugees on the high seas has assumed a newfound importance. This article examines the flawed system provided by the ‘Constitution of the Oceans’, the UN Convention on the Law of the Sea for the protection of the lives of migrants at sea. It submits that international refugee law is well-equipped to assume a greater responsibility in ensuring the protection of those involved. Although the concept of non-refoulement cannot be stretched ad absurdum, it may still be reasonably interpreted as providing a temporary right to disembark for the purpose of processing possible asylum applications. In the long-term, a system of burden-sharing and permanent, yet flexible, reception agreements remain the only sustainable solution
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