798 research outputs found

    A generalized topological recursion for arbitrary ramification

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    The Eynard-Orantin topological recursion relies on the geometry of a Riemann surface S and two meromorphic functions x and y on S. To formulate the recursion, one must assume that x has only simple ramification points. In this paper we propose a generalized topological recursion that is valid for x with arbitrary ramification. We justify our proposal by studying degenerations of Riemann surfaces. We check in various examples that our generalized recursion is compatible with invariance of the free energies under the transformation (x,y) -> (y,x), where either x or y (or both) have higher order ramification, and that it satisfies some of the most important properties of the original recursion. Along the way, we show that invariance under (x,y) -> (y,x) is in fact more subtle than expected; we show that there exists a number of counter examples, already in the case of the original Eynard-Orantin recursion, that deserve further study.Comment: 26 pages, 2 figure

    Australian Hackers and Ethics

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    The aim of the paper is to look at the way hackers act and ways in which society can protect itself. The paper will show the current views and attitudes of hackers in an Australian context. The paper will also include a case study to show how a hacking incident can develop and how technology can be used to protect against hacking

    Principles of information warfare

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    This paper examines the fundamental concepts needed to understand the broad spectrum of activities encompassed by the Information Warfare phenomenon. It provides a theoretical background to these activities, and examines the context in which these are most effective.<br /

    Harm reduction among injecting drug users - evidence of effectiveness

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    This chapter synthesises and evaluates the available direct evidence relating to the impact of needle and syringe programmes (NSPs), opioid substitution treatment (OST), drug consumption rooms (DCRs), and peer naloxone distribution (PND) on HIV/hepatitis C (HCV) incidence/prevalence, injecting risk behaviour and overdose-related mortality. To achieve this, we conducted a review of reviews; a systematic and explicit method used to identify, select and critically appraise relevant findings from secondary level research (systematic reviews and/or meta-analyses) into an evidence briefing. In the absence of high-quality reviews, appraisal of the evidence was supplemented with a targeted review of the primary literature. We find that there is sufficient review-level evidence that OST reduces HIV transmission, while the evidence in support of NSPs reducing HIV transmission is more tentative, and for DCRs currently insufficient. There is tentative evidence that OST has limited effectiveness in reducing HCV transmission, and insufficient evidence to support or discount NSPs or DCRs' ability to reduce HCV transmission. There is sufficient review-level evidence that NSPs, OST and DCRs reduce self-reported injecting risk behaviour. There is sufficient review evidence that OST reduces risk of overdose mortality, but insufficient evidence to support or discount the effect of DCRs or PND on overdose deaths at the community level. Our review shows evidence in support of a variety of harm reduction interventions but highlights an uneven presence of high-quality review evidence. Future evaluation of harm reduction programmes should prioritise methodologically robust study designs

    Cost-effectiveness of HCV case-finding for people who inject drugs via dried blood spot testing in specialist addiction services and prisons

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    ObjectivesPeople who inject drugs (PWID) are at high risk for acquiring hepatitis C virus (HCV), but many are unaware of their infection. HCV dried blood spot (DBS) testing increases case-finding in addiction services and prisons. We determine the cost-effectiveness of increasing HCV case-finding among PWID by offering DBS testing in specialist addiction services or prisons as compared to using venepuncture.DesignCost-utility analysis using a dynamic HCV transmission model among PWID, including: disease progression, diagnosis, treatment, injecting status, incarceration and addition services contact.Setting uk interventionDBS testing in specialist addiction services or prisons. Intervention impact was determined by a meta-analysis of primary data.Primary and secondary outcome measuresCosts (in UK ÂŁ, ÂŁ1=US$1.60) and utilities (quality-adjusted life years, QALYs) were attached to each state and the incremental cost effectiveness ratio (ICER) determined. Multivariate uncertainty and one-way sensitivity analyses were performed.ResultsFor a ÂŁ20 000 per QALY gained willingness-to-pay threshold, DBS testing in addiction services is cost-effective (ICER of ÂŁ14 600 per QALY gained). Under the base-case assumption of no continuity of treatment/care when exiting/entering prison, DBS testing in prisons is not cost-effective (ICER of ÂŁ59 400 per QALY gained). Results are robust to changes in HCV prevalence; increasing PWID treatment rates to those for ex-PWID considerably reduces ICER (ÂŁ4500 and ÂŁ30 000 per QALY gained for addiction services and prison, respectively). If continuity of care is &gt;40%, the prison DBS ICER falls below ÂŁ20 000 per QALY gained.ConclusionsDespite low PWID treatment rates, increasing case-finding can be cost-effective in specialist addiction services, and in prisons if continuity of treatment/care is ensured

    Australian Critical Infrastructure Protection: A case of two tales

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    The protection of critical infrastructures and the choices made in terms of priorities and cost, all impact upon the planning, precautions and security aspects of protecting these important systems. Often the when choices made is difficult to assess at the time the decision is taken and it is only after an incident that the truth of the choices made become fully evident. The paper focuses on two recent examples of Australian Critical Infrastructure protection and the issues that related to those examples

    The Derivation of a Conceptual Model for Outsourcing IT Security

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    IT security outsourcing is the establishment of a contractual relationship between an organization with an outside vendor which assumes responsibility for the organisation’s security functions. Outsourcing in IS has had a variable history of success and the complexity of the decision making process leads to a substantial degree of uncertainty. This is especially so in the realm of IS security since the protection of both hardware and software systems is placed in the hands of an external provider. This paper is a fuller and more comprehensive paper of a previous paper outlining the effectiveness of the decision making process by means of a conceptual model using Soft System Methodology techniques that integrates security benefits, costs and their respective performance measures. In this paper the methodology used to develop the model is discussed in detail

    Australian critical infrastructure protection : a case of two tales

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    The protection of critical irifrastructures and the choices made in terms of priorities and cost, all impact upon the planning, precautions and security aspects of protecting these important systems. Often the when choices made is difficult to assess at the time the decision is taken and it is only after an incident that the truth of the choices made become fit!ly evident. The paper focllses on two recent examples of Australian Critical Infrastructure protection and the issues that related to those examples.<br /

    Method for assigning satellite lines to crystallographic sites in rare-earth crystals

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    We describe an experimental technique for associating the satellite lines in a rare-earth optical spectrum caused by a defect with the rare-earth ions in crystal sites around that defect. This method involves measuring the hyperfine splitting caused by
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