937 research outputs found

    A first broad-scale molecular phylogeny of Prionoceridae (Coleoptera: Cleroidea) provides insight into taxonomy, biogeography and life history evolution

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    © Senckenberg Gesellschaft fur Naturforschung, 2016. This is an open access article. Authors are permitted to post a PDF of their own articles, as provided by the publisher, on their personal web pages or the web page of their institution. Any commercial use is excluded. The attached file is the published version of the article

    The Effect Of Pitting Corrosion On The Position Of Aircraft Structural Failures

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    Corrosion has been shown over the last decade to significantly reduce the structural integrity of aircraft as they age. Previous work at DSTO has shown that pitting and exfoliation corrosion are particularly deleterious to aircraft structural integrity. In addition to reducing fatigue endurance, pitting also increases the surface area of the component over which fatigue failures can occur. This paper reports the results of a Monte-Carlo model of this phenomenon, which has been labelled 'corrosion criticality'. This model concentrates on the effect of the pit spatial density and position on the endurance of a fatigue coupon designed to mimic a simple aircraft component. The study's results show that pitting increases the area of the coupon over which failures can occur

    Providing marketing information to smallholders in Zimbabwe: What can the state usefully do?

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    In recent decades, significant international assistance has been provided to assist the establishment of market information systems (MISs) in a range of developing countries, including many in Africa. However, experience with state-run MISs, looking to provide current price information to market participants, has not been encouraging. Volatile horticultural markets provide particular challenges for such MISs. Therefore, it is suggested that it might be more appropriate to provide other types of marketing information to inform the production and marketing decisions of smallholder producers. This paper reports on recent efforts by the national extension agency, Agritex, to provide such information to smallholder horticultural producers in two districts of north-eastern Zimbabwe. Drawing on an initial evaluation of this pilot programme, the paper suggests that: 1) in the Zimbabwe case, the extension service may provide a viable vehicle for dissemination of marketing information to smallholder (horticultural) producers; 2) information on new crops and market opportunities is valued more highly by farmers than information on current market prices; 3) such information should complement, not supplant, traditional production extension advice. The paper concludes by considering some of the issues pertaining to the continuation and expansion of the pilot programme.Marketing,

    Proof Systems for Retracts in Simply Typed Lambda Calculus

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    Abstract. This paper concerns retracts in simply typed lambda calculus assuming βη-equality. We provide a simple tableau proof system which characterises when a type is a retract of another type and which leads to an exponential decision procedure.

    A New Technique for Finding Needles in Haystacks: A Geometric Approach to Distinguishing Between a New Source and Random Fluctuations

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    We propose a new test statistic based on a score process for determining the statistical significance of a putative signal that may be a small perturbation to a noisy experimental background. We derive the reference distribution for this score test statistic; it has an elegant geometrical interpretation as well as broad applicability. We illustrate the technique in the context of a model problem from high-energy particle physics. Monte Carlo experimental results confirm that the score test results in a significantly improved rate of signal detection.Comment: 5 pages, 4 figure

    Historical Criminology and the Explanatory Power of the Past

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    To what extent can the past ‘explain’ the present? This deceptively simple question lies at the heart of historical criminology (research which incorporates historical primary sources while addressing present-day debates and practices in the criminal justice field). This article seeks first to categorise the ways in which criminologists have used historical data thus far, arguing that it is most commonly deployed to ‘problematize’ the contemporary rather than to ‘explain’ it. The article then interrogates the reticence of criminologists to attribute explicative power in relation to the present to historical data. Finally, it proposes the adoption of long time-frame historical research methods, outlining three advantages which would accrue from this: the identification and analysis of historical continuities; a more nuanced, shared understanding of micro/macro change over time in relation to criminal justice; and a method for identifying and analysing instances of historical recurrence, particularly in perceptions and discourses around crime and justice

    Plural policing in Europe:relationships and governance in contemporary security system

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    References to ‘plural policing’, ‘policing beyond the police’ and the ‘extended policing family’ are now commonplace in many discussions of policing in late modern societies. There is a danger that claims about the dynamic and changing nature of plural policing themselves become a new orthodoxy and begin to lose a sense of local nuance and recognition of the importance of place-based specificity and context in understanding the particularities of policing. It is this need to unpack the complex ways in which contemporary plural policing is now configured at a local level within different national political environments that provides the underpinning rationale for this Special Issue. Focussing on aspects of relationships and governance in six jurisdictions across northern and western Europe, it provides important insights into how the policies, practices and narratives around plural policing reflect the influence of particular histories and geographies. The first three articles are focused primarily on the relationships which have emerged in the public sector through its own processes of pluralisation, in particular, through the introduction of policing auxiliaries or municipal policing in Scotland, England and The Netherlands. The fourth article considers both relationships and governance in pluralised policing in Paris, France. A detailed analysis of the governance of safety and security is taken up in the final two articles, examining the cases of Austria and Belgium. These articles clearly demonstrate that experiences of pluralised policing vary widely within Europe and call into question the assumed dominance of neo-liberal forces in this area

    Questioning the Influence of Sunspots on Amazon Hydrology: Even a Broken Clock Tells the Right Time Twice a Day

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    It was suggested in a recent article that sunspots drive decadal variation in Amazon River flow. This conclusion was based on a novel time series decomposition method used to extract a decadal signal from the Amazon River record. We have extended this analysis back in time, using a new hydrological proxy record of tree ring oxygen isotopes (δ¹⁸OTR). Consistent with the findings of Antico and Torres, we find a positive correlation between sunspots and the decadal δ¹⁸OTR cycle from 1903 to 2012 (r = 0.60, p < 0.001). However, the relationship does not persist into the preceding century and even becomes weakly negative (r = −0.30, p = 0.11, 1799–1902). This result casts considerable doubt over the mechanism by which sunspots are purported to influence Amazon hydrology
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