2,986 research outputs found

    Exact Results on e+ e- --> e+ e- + 2 Photons at SLC/LEP Energies

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    We use the spinor methods of the CALKUL collaboration, as realized by Xu, Zhang and Chang, to calculate the differential cross section for e+ e- --> e+ e- + 2 photons for c.m.s. energies in the SLC/LEP regime. An explicit complete formula for the respective cross section is obtained. The leading log approximation is used to check the formula. Applications of the formula to high precision luminosity calculations at SLC/LEP are discussed.Comment: 16 pages(LaTeX), UTHEP-92-0601 (contains corrected figures

    Adapting to change: Time for climate resilience and a new adaptation strategy. EPC Issue Paper 5 March 2020

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    The dramatic effects of climate change are being felt across the European continent and the world. Considering how sluggish and unsuccessful the world has been in reducing greenhouse gas (GHG) emissions, the impacts will become long-lasting scars. Even implementing radical climate mitigation now would be insufficient in addressing the economic, societal and environmental implications of climate change, which are expected to only intensify in the years to come. This means climate mitigation must go hand in hand with the adaptation efforts recognised in the Paris Agreement. And although the damages of climate change are usually localised and adaptation measures often depend on local specificities, given the interconnections between ecosystems, people and economies in a globalised world there are strong reasons for European Union (EU) member states to join forces, pool risk and cooperate across borders. Sharing information, good practices, experiences and resources to strengthen resilience and enhance adaptive capacity makes sense economically, environmentally and socially. The European Commission’s 2013 Adaptation Strategy is the first attempt to set EU-wide adaptation and climate resilience and could be considered novel in that it tried to mainstream adaptation goals into relevant legislation, instruments and funds. It was not very proactive, however. It also lacked long-term perspective, failed to put the adaptation file high on the political agenda, was under resourced, and suffered from knowledge gaps and silo thinking. The Commission’s European Green Deal proposal, which has been presented as a major step forward to the goal of Europe becoming the world’s first climate-neutral continent, suggests that the Commission will adopt a new EU strategy on adaptation to climate within the first two years of its mandate (2020-2021). In light of the risks climate change poses to ecosystems, societies and the economy (through inter alia the vulnerability of the supply chain to climate change and its potential failure to provide services to consumers), adaptation should take a prominent role alongside mitigation in the EU’s political climate agenda. Respecting the division of treaty competences, there are important areas where EU-wide action and support could foster the continent’s resilience to climate change. The European Policy Centre (EPC) project “Building a climate-resilient Europe”, which has culminated in this Issue Paper, has identified the following: (i) the ability to convert science-based knowledge into preventive action and responsible behaviour, thus filling the information gap; (ii) the need to close the protection gap through better risk management and risk sharing; (iii) the necessity to adopt nature-based infrastructural solutions widely and tackle the grey infrastructure bias; and (iv) the need to address the funding and investment gap. This Issue Paper aims to help inform the upcoming EU Adaptation Strategy and, by extension, strengthen the EU’s resilience to climate change. To that end, the authors make a call for the EU to mainstream adaptation and shift its focus from reacting to disasters to a more proactive approach that prioritises prevention, risk reduction and resilience building. In doing so, the EU must ensure fairness and distributive justice while striving for climate change mitigation and protecting the environment and biodiversity. To succeed, the new EU Adaptation Strategy will need to address specific challenges related to the information, protection, funding and investment gaps; and the grey infrastructure bias. To tackle and address those challenges, this Paper proposes 17 solutions outlined in Table 1 (see page 6)

    On Principal Admissible Representations and Conformal Field Theory

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    The principal admissible representations of affine Kac-Moody algebras are studied, with a view to their use in conformal field theory. We discuss the generation of the set of principal admissible highest weights, concentrating mainly on Ar(1)A_r^{(1)} at rational level kk. A related algorithm is described that produces the Malikov-Feigen-Fuchs null vectors of these representations. With the principal admissible description of the highest weights, we are able to prove that field identifications (including maverick ones) lead to the canonical description of the primary fields of the nonunitary diagonal coset theories.Comment: Harvmac (b mode : 32 p; l mode: 36 p), 5 figures, some minor reformulations, references added and typos correcte

    Multimodal fuzzy fusion for enhancing the motor-imagery-based brain computer interface

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    © 2005-2012 IEEE. Brain-computer interface technologies, such as steady-state visually evoked potential, P300, and motor imagery are methods of communication between the human brain and the external devices. Motor imagery-based brain-computer interfaces are popular because they avoid unnecessary external stimuli. Although feature extraction methods have been illustrated in several machine intelligent systems in motor imagery-based brain-computer interface studies, the performance remains unsatisfactory. There is increasing interest in the use of the fuzzy integrals, the Choquet and Sugeno integrals, that are appropriate for use in applications in which fusion of data must consider possible data interactions. To enhance the classification accuracy of brain-computer interfaces, we adopted fuzzy integrals, after employing the classification method of traditional brain-computer interfaces, to consider possible links between the data. Subsequently, we proposed a novel classification framework called the multimodal fuzzy fusion-based brain-computer interface system. Ten volunteers performed a motor imagery-based brain-computer interface experiment, and we acquired electroencephalography signals simultaneously. The multimodal fuzzy fusion-based brain-computer interface system enhanced performance compared with traditional brain-computer interface systems. Furthermore, when using the motor imagery-relevant electroencephalography frequency alpha and beta bands for the input features, the system achieved the highest accuracy, up to 78.81% and 78.45% with the Choquet and Sugeno integrals, respectively. Herein, we present a novel concept for enhancing brain-computer interface systems that adopts fuzzy integrals, especially in the fusion for classifying brain-computer interface commands

    Explaining the EU's Policy Portfolio: Applying a Federal Integration Approach to EU Cohesion Policy. Bruges Political Research Paper No. 20, December 2011

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    This paper engages with the debate about why the nature of the EU's policy portfolio is as it is. It does so by taking cohesion policy and asking the question, why has it come to occupy so important a position in the EU‟s policy portfolio? It is argued that the two most common conceptually-based approaches applied to cohesion policy – intergovernmentalism and multilevel governance – do not adequately explain either the timing or the dynamic of cohesion policy. A model that combines economic integration approaches and federal approaches is developed in the paper to provide a basis for a new explanatory framework for the prominent position of cohesion in the portfolio. We suggest that our approach – which we call a federal integration approach – has the potential to be applied to other policy areas

    Think Tank Review Issue 76 March 2020

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