21 resultados para Prove it works
Resumo:
Nowadays few people consider finding their way in unfamiliar areas a problem as a GPS (Global Positioning System) combined with some simple map software can easily tell you how to get from A to B. Although this opportunity has only become available during the last decade, recent experiments show that long-distance migrating animals had already solved this problem. Even after displacement over thousands of kilometres to previously unknown areas, experienced but not first time migrant birds quickly adjust their course toward their destination, proving the existence of an experience-based GPS in these birds. Determining latitude is a relatively simple task, even for humans, whereas longitude poses much larger problems. Birds and other animals however have found a way to achieve this, although we do not yet know how. Possible ways of determining longitude includes using celestial cues in combination with an internal clock, geomagnetic cues such as magnetic intensity or perhaps even olfactory cues. Presently, there is not enough evidence to rule out any of these, and years of studying birds in a laboratory setting have yielded partly contradictory results. We suggest that a concerted effort, where the study of animals in a natural setting goes hand-in-hand with lab-based study, may be necessary to fully understand the mechanism underlying the long-distance navigation system of birds. As such, researchers must remain receptive to alternative interpretations and bear in mind that animal navigation may not necessarily be similar to the human system, and that we know from many years of investigation of long-distance navigation in birds that at least some birds do have a GPS-but we are uncertain how it works.
Resumo:
In this paper, we show how interacting and occluding targets can be tackled successfully within a Gaussian approximation. For that purpose, we develop a general expansion of the mean and covariance of the posterior and we consider a first order approximation of it. The proposed method differs from EKF in that neither a non-linear dynamical model nor a non-linear measurement vector to state relation have to be defined, so it works with any kind of interaction potential and likelihood. The approach has been tested on three sequences (10400, 2500, and 400 frames each one). The results show that our approach helps to reduce the number of failures without increasing too much the computation time with respect to methods that do not take into account target interactions.
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The metallo-phthalocyanines (MPcs) are an interesting group of organic semiconductor materials for applications such as large area solar cells due to their optoelectronic properties coupled with the possibility of easily and cheaply fabricating thin films of MPcs [1, 2]. As for organic semiconductors in general, many of the interesting properties of the MPcs such as magnetism, light absorption and charge transport, are highly anisotropic [2, 3]. To maximise the efficiency of a device based on these materials it is therefore important to study their molecular orientation in films and to assess the influence of different growth conditions and substrate treatments.
X-ray diffraction is a well established and powerful technique for studying texture (and hence molecular orientation) in crystalline materials, but it cannot provide any information about amorphous or nanocrystalline films. In electron paramagnetic resonance (EPR) spectroscopy the signal comes from the spin of unpaired electrons in the material. This technique therefore does not require the sample to be crystalline. It works for any sample with paramagnetic centres such as the MPcs where the unpaired electrons are contributed by the metal. In this paper we present a continuous-wave X-band EPR study using the anisotropy of the EPR spectrum of CuPc [4] to determine the orientation effects in different types of CuPc films. From these measurements we gain insight into the molecular arrangement of films with different spin concentrations, and apply our technique to the study of molecular orientation in photovoltaic cells.
Resumo:
Efficient identification and follow-up of astronomical transients is hindered by the need for humans to manually select promising candidates from data streams that contain many false positives. These artefacts arise in the difference images that are produced by most major ground-based time-domain surveys with large format CCD cameras. This dependence on humans to reject bogus detections is unsustainable for next generation all-sky surveys and significant effort is now being invested to solve the problem computationally. In this paper, we explore a simple machine learning approach to real-bogus classification by constructing a training set from the image data of similar to 32 000 real astrophysical transients and bogus detections from the Pan-STARRS1 Medium Deep Survey. We derive our feature representation from the pixel intensity values of a 20 x 20 pixel stamp around the centre of the candidates. This differs from previous work in that it works directly on the pixels rather than catalogued domain knowledge for feature design or selection. Three machine learning algorithms are trained (artificial neural networks, support vector machines and random forests) and their performances are tested on a held-out subset of 25 per cent of the training data. We find the best results from the random forest classifier and demonstrate that by accepting a false positive rate of 1 per cent, the classifier initially suggests a missed detection rate of around 10 per cent. However, we also find that a combination of bright star variability, nuclear transients and uncertainty in human labelling means that our best estimate of the missed detection rate is approximately 6 per cent.
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The third edition of this dynamic book has been fully revised and updated to provide a comprehensive introduction to contemporary politics in the Middle East. Purposefully employing a clear thematic structure and including a wide range of case studies, data, visuals and further reading guidance the book explores and analyses the major issues which define the politics of this region of the globe.
Milton-Edwards begins by introducing and explaining key concepts and debates and goes on to outline the impact of colonialism and its legacy, the rise of Arab nationalism and anti-colonial politics. She then examines major political issues affecting the region, such as American foreign policy, political Islam, war and conflict, political economy, democratization, ethnicity and the role of women. The book concludes by highlighting the politics of the region in the twenty-first century and the future challenges it faces. This is a perfect introduction for undergraduates, covering key political, economic and social debates and providing updates and guidance for further reading.
"The genius of this book is that it integrates together the different themes which run through Middle Eastern politics. The coherence of the approach which the author has adopted is indicated by the manner in which she has updated the work in this second edition. Despite the substantial changes which the East has undergone since 9/11 and the 2003 Gulf War, the original line of analysis retains all its force. It remains a key reference for all those who are seeking to understand the region's politics, whether undergraduates, postgraduates or lay readers."
Tim Niblock, Exeter University
"I welcome the new edition of this comprehensive guide to the politics of such an important region of the world. It combines sensible generalizations with useful case studies of particularly important subjects. It is a must for all those who want to understand the complex politics of the modern Middle East."
Roger Owen, Harvard University
"Beverley Milton-Edwards has produced an excellent book, which is both wide-ranging in its coverage and punchy in its arguments. As such, its functions are dual. It works well as a text book, introducing the general reader to key themes in the contemporary region, from oil politics to ethnicity, to women and nationalism. But it also works as a running commentary on key debates, such as the rile of colonialism and the relationship between Islam and democracy. In short, this is a book with attitude."
Philip Robins, St Antony's College, Oxford
Resumo:
Realistic Evaluation assumes that all programmes implemented in practice have an underlying theory to explain how a particular intervention is meant to work. The purpose of realist evaluation is to test the theoretical propositions underpinning the implementation of a programme in order to understand how and why it works, or might not work, in certain circumstances. The first stage of the realist evaluation is to track and articulate the programme theories to determine the evidence on the ‘official conjecture’ (Pawson et al 2004 pg 16) of how the programme is suppose to work in practice. These official conjectures are then tested and refined by gathering empirical evidence to establish causal relationships between a programme and its outcome. Evaluation of the factors and interactions between factors, supporting or hindering the implementation of a programme in practice facilitate theory refinement. Theory refinement is viewed as an iterative and cyclical process undertaken to synthesise the empirical evidence and develop mid-range theories which can be generalised and applied to other programmes to improve implementation and sustainability. In this symposium an example of realist evaluation used to test and refine the theory underpinning the implementation of Early Warning Systems (EWS) is provided to clarify how this theory driven approach can be applied in practice.
Resumo:
The goal of this work is to present an efficient CAD-based adjoint process chain for calculating parametric sensitivities (derivatives of the objective function with respect to the CAD parameters) in timescales acceptable for industrial design processes. The idea is based on linking parametric design velocities (geometric sensitivities computed from the CAD model) with adjoint surface sensitivities. A CAD-based design velocity computation method has been implemented based on distances between discrete representations of perturbed geometries. This approach differs from other methods due to the fact that it works with existing commercial CAD packages (unlike most analytical approaches) and it can cope with the changes in CAD model topology and face labeling. Use of the proposed method allows computation of parametric sensitivities using adjoint data at a computational cost which scales with the number of objective functions being considered, while it is essentially independent of the number of design variables. The gradient computation is demonstrated on test cases for a Nozzle Guide Vane (NGV) model and a Turbine Rotor Blade model. The results are validated against finite difference values and good agreement is shown. This gradient information can be passed to an optimization algorithm, which will use it to update the CAD model parameters.
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The water and wastewater industry in the UK accounts for around 3% of total energy use and just over 1% of total UK greenhouse gas emissions. Targets for greenhouse gas emissions reduction and higher renewable energy penetration, coupled with rising energy costs, growing demand for wastewater services and tightening EU water quality requirements, have led to an increased interest in alternative wastewater treatment methods. The use of short rotation coppice (SRC) willow for the treatment of wastewater effluent is one such alternative, which brings with it the dual benefits of wastewater treatment and production of biomass for energy. In order to assess the effectiveness of SRC willow, it is important to analyse the overall energy balance in terms of energy input versus energy output. This paper carries out an energy life cycle analysis of a specific SRC willow plantation in Northern Ireland to which farmyard washings (dirty water) are applied. The system boundaries include the establishment, maintenance, and harvesting of the plantation, along with the transport and drying of the wood for biomass combustion. The analysis shows that the overall energy balance is positive, and that the direct and indirect energy demands are 12% and 8% of gross energy production respectively. The energy demands of the plantation are compared with the energy required to treat an equivalent nutrient load in a conventional wastewater treatment plant. While a conventional plant consumes 2.6 MJ/m3 , the irrigation system consumes 1.6 MJ/m3 and the net energy production of the scenario is 48 MJ/m3 .
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Volume III of the new eleven-volume edition of Milton's Complete Works provides a definitive scholarly edition of all of Milton's shorter poems in English, Latin, Italian, and Greek, as well as his Mask, taken from both published and manuscript sources. It includes his 1645 Poems complete with all prefatory materials, thus illuminating the ways in which author, publisher, and print shop shaped this volume. It then presents all the new poems added in the 1673 edition (with the new Table of Contents), as well as the poems omitted from both editions. A careful collation of textual variants among these sources as well as the 1637 anonymous publication of Milton's Mask is provided. The Bridgewater manuscript of Milton's Mask (probably close to the acting version) and his working copy from the Trinity Manuscript, with its many alterations and additions, are transcribed in their entirety, so that the various versions may be compared and studied.
A special feature of this edition is a new translation of Milton's many Latin and Greek poems that is both accurate and attentive to their literary qualities. This is augmented by a detailed and comprehensive commentary that highlights classical, vernacular, and neo-Latin parallels. A poetic translation of Milton's six Italian sonnets and Canzone is also supplied. In addition, the Appendices contain all the versions of Milton's shorter poems in all the contemporary manuscript and printed sources, so they may be examined in relation to their specific contexts. The transcription of all the versions of Milton's poems in the Trinity Manuscript allows in several cases, notably 'Lycidas' and 'At a Solemn Music,' for examination of the evolution of these poems as Milton weighed choiced of diction and sound qualities, enabling further understanding of his poetic practices.
Barbara Lewalski is responsible for text, textual apparatus, and commentary pertaining to the vernacular poems in all sections of this edition including the appendices, and manuscript transcriptions (with the exception of A Maske), as well as the Occasions, Vernacular Poems,and Textual Introductions. Estelle Haan is responsible for text, textual apparatus, and commentary for the Poemata in all sections of this edition,and for the Poemata Introduction. She has also provided all translations from Latin, Italian, and Greek in the Testimonia, Poemata, and associated commentary, and transcriptions of the BL Damon, the Bodleian AdJoannem Rousium, and A Maske from the Trinity and Bridgewater manuscripts. Andrew McNeillie has provided poetic translations for Milton’s Italian sonnets, and Jason Rosenblatt has provided some Hebrew text and commentary pertaining to Milton’s Psalm translations.John Cunningham has transcribed Henry Lawes’ music for Milton’s masque, with commentary (Appendix E). Biblical references are taken from the King James (Authorized) Version.
Resumo:
This article argues that, when a printed page is initially orally generated and then transcribed, either at the time or on a subsequent occasion by a listener or an interlocutor, there are important critical implications for the “I” of the account. It takes as a case study Anna Trapnel's first published works. Appearing within a few weeks of each other in 1654, The Cry of a Stone and Strange and Wonderful News are both mediated texts, large parts of which depend on the agency of a relater. The article begins by examining the textual traces of the relater, arguing for the centrality of his role and other agencies in the shaping of the works which bear Trapnel's name. Situating itself in relation to a current orientation in feminist autobiographical theory that places emphasis on the external requirement to narrate one's life, rather than on the spontaneous production of autobiography by an inner self, the article emphasizes notions of coaxing, witnessing and intersubjectivity to point up an appreciation of women's life writing as a species of cultural production in which various historical actors—male and female—participate. This dialogic process, which persists into the afterlife of transcription, owes part of its genesis to the political vagaries of 1654 and precipitates two contrasting—but equally “authentic”—versions of Trapnel's life and self. Mapping this movement, discussion concentrates on the ways in which a critical confrontation with women's oral narrative is as much an activity of disentangling as it is of reconstructing, an activity which is revealing of the extent to which a spectrum of social and cultural networks participates in and facilitates the female writing act.
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This paper aims to contribute to the current debate on Marine Spatial Planning (MSP) by exploring the issue of stakeholder engagement. MSP is an emergent policy field that is subject to an increasing body of research, yet the role, scope and nature of participatory engagement within the process remains a neglected topic. This paper briefly reviews the nature of the ‘marine problem’, to which MSP is seen to be the response and describes the emergence of MSP policy in the UK with specific emphasis on participatory aspects. Drawing on the experience of terrestrial planning it discusses the potential benefits of stakeholder engagement in MSP and highlights some of the key issues that need to be taken into account when shaping stakeholder input into the process. It then goes on to describe the findings from a series of interviews with key stakeholders in the Irish Sea Region, which suggest that we need to develop a more critical and deeper understanding of how various interests frame the ‘marine problem’, and how they see their role in shaping the form of the MSP process. This highlights the importance of encouraging stakeholder involvement in MSP, the need to develop a shared vision of a ‘sea interest’. Priorities are then set for research to support this important policy agenda.
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Despite the growing sophistication of antitrust regimes around the world, export cartels benefit from special treatment: they are almost universally tolerated, if not encouraged in the countries of origin. Economists do not offer an unambiguous policy recommendation on how to deal with them in part due to the lack of empirical data. This article discusses arguments for and against export cartels and it identifies the existing gaps in the present regulatory framework. The theoretical part is followed by an analysis of the recent case law: a US cartel challenged with different outcomes in India and South Africa, as well as Chinese export cartels pursued in the USA. The Chinese cases are particularly topical as the conduct at stake, apart from being subject to private antitrust actions before US courts, was also challenged within the WTO dispute settlement framework, pointing out to the existing interface between trade and competition. While the recent developments prove that unaddressed issues tend not to vanish, the new South-North dimension has the potential of placing export cartels again on the international agenda. Pragmatic thinking suggests looking for the solution within the WTO framework.