8,840 research outputs found

    European Retrofit Network: Retrofitting Evaluation Methodology Report

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    The research programme, funded by the EU Progress Fund, looks at the potential impacts of construction training in the area of „retrofitting‟ social housing to make it more sustainable, in particular to improve energy efficiency and reduce greenhouse gas emissions. This report investigates methodologies for measuring and demonstrating carbon emissions reductions resulting from retrofitting measures in the partner countries (UK, Spain, Poland and Montenegro). The output of this part of the study is a methodology appropriate to measuring the likely carbon reduction impacts through common retrofit measures in the social housing sector, taking into account the likely cost effectiveness of measures, the impact on occupants, the project management challenges and thus the measures that are most likely to be employed in policy and practice. An appropriate methodology is one that can be applied across the range of different conditions found in the partner countries (representative to some degree of the range of conditions found across Europe as whole). Low carbon retrofit has been defined as „incremental improvements to the building fabric and systems with primary intention of improving energy efficiency and reducing carbon emissions.

    A study of the kinematics and binary-induced shaping of the planetary nebula HaTr 4

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    We present the first detailed spatio-kinematical analysis and modelling of the planetary nebula HaTr 4, one of few known to contain a post-common-envelope central star system. Common envelope evolution is believed to play an important role in the shaping of planetary nebulae, but the exact nature of this role is yet to be understood. High spatial- and spectral- resolution spectroscopy of the [OIII]5007 nebular line obtained with VLT-UVES are presented alongside deep narrowband Ha+[NII]6584 imagery obtained using EMMI-NTT, and together the two are used to derive the three-dimensional morphology of HaTr 4. The nebula is found to display an extended ovoid morphology with an enhanced equatorial region consistent with a toroidal waist - a feature believed to be typical amongst planetary nebulae with post-common-envelope central stars. The nebular symmetry axis is found to lie perpendicular to the orbital plane of the central binary, concordant with the idea that the formation and evolution of HaTr 4 has been strongly influenced by its central binary.Comment: 9 pages, 5 figures, accepted for publication in MNRA

    Coronary heart disease risks associated with high levels of HDL cholesterol.

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    BackgroundThe association between high-density lipoprotein cholesterol (HDL-C) and coronary heart disease (CHD) events is not well described in individuals with very high levels of HDL-C (>80 mg/dL).Methods and resultsUsing pooled data from 6 community-based cohorts we examined CHD and total mortality risks across a broad range of HDL-C, including values in excess of 80 mg/dL. We used Cox proportional hazards models with penalized splines to assess multivariable, adjusted, sex-stratified associations of HDL-C with the hazard for CHD events and total mortality, using HDL-C 45 mg/dL and 55 mg/dL as the referent in men and women, respectively. Analyses included 11 515 men and 12 925 women yielding 307 245 person-years of follow-up. In men, the association between HDL-C and CHD events was inverse and linear across most HDL-C values; however at HDL-C values >90 mg/dL there was a plateau effect in the pattern of association. In women, the association between HDL-C and CHD events was inverse and linear across lower values of HDL-C, however at HDL-C values >75 mg/dL there were no further reductions in the hazard ratio point estimates for CHD. In unadjusted models there were increased total mortality risks in men with very high HDL-C, however mortality risks observed in participants with very high HDL-C were attenuated after adjustment for traditional risk factors.ConclusionsWe did not observe further reductions in CHD risk with HDL-C values higher than 90 mg/dL in men and 75 mg/dL in women

    A Buffer Stocks Model for Stabilizing Price of Staple Food with Considering the Expectation of Non Speculative Wholesaler

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    This paper is a study of price stabilization in the staple food distribution system. All stakeholders experience market risks due to some possibility causes of price volatility. Many models of price stabilization had been developed by employing several approaches such as floor-ceiling prices, buffer funds, export or import taxes, and subsidies. In the previous researches, the models were expanded to increase the purchasing price for producer and decrease the selling price for consumer. Therefore, the policy can influence the losses for non-speculative wholesaler that is reflected by the descending of selling quantity and ascending of the stocks. The objective of this model is not only to keep the expectation of both producer and consumer, but also to protect non-speculative wholesaler from the undesirable result of the stabilization policy. A nonlinear programming model was addressed to determine the instruments of intervention program. Moreover, the result shows that the wholesaler behavior affects the intervention costs. Index Terms Buffer stocks, Price stabilization, Nonlinear programming, Wholesaler behavior

    Implementation of a Deutsch-like quantum algorithm utilizing entanglement at the two-qubit level, on an NMR quantum information processor

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    We describe the experimental implementation of a recently proposed quantum algorithm involving quantum entanglement at the level of two qubits using NMR. The algorithm solves a generalisation of the Deutsch problem and distinguishes between even and odd functions using fewer function calls than is possible classically. The manipulation of entangled states of the two qubits is essential here, unlike the Deutsch-Jozsa algorithm and the Grover's search algorithm for two bits.Comment: 4 pages, two eps figure

    Specializing Interpreters using Offline Partial Deduction

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    We present the latest version of the Logen partial evaluation system for logic programs. In particular we present new binding-types, and show how they can be used to effectively specialise a wide variety of interpreters.We show how to achieve Jones-optimality in a systematic way for several interpreters. Finally, we present and specialise a non-trivial interpreter for a small functional programming language. Experimental results are also presented, highlighting that the Logen system can be a good basis for generating compilers for high-level languages

    Proof Relevant Corecursive Resolution

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    Resolution lies at the foundation of both logic programming and type class context reduction in functional languages. Terminating derivations by resolution have well-defined inductive meaning, whereas some non-terminating derivations can be understood coinductively. Cycle detection is a popular method to capture a small subset of such derivations. We show that in fact cycle detection is a restricted form of coinductive proof, in which the atomic formula forming the cycle plays the role of coinductive hypothesis. This paper introduces a heuristic method for obtaining richer coinductive hypotheses in the form of Horn formulas. Our approach subsumes cycle detection and gives coinductive meaning to a larger class of derivations. For this purpose we extend resolution with Horn formula resolvents and corecursive evidence generation. We illustrate our method on non-terminating type class resolution problems.Comment: 23 pages, with appendices in FLOPS 201

    Au-catalyzed biaryl coupling to generate 5- to 9-membered rings: turnover-limiting reductive elimination versus π-complexation

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    The intramolecular gold–catalyzed arylation of arenes by aryltrimethylsilanes has been investigated from both a mechanistic and preparative aspect. The reaction generates five to nine membered rings, and of the 44 examples studied, ten include a heteroatom (N, O). The tethering of the arene to the arylsilane not only provides a tool to probe the impact of the conforma-tional flexibility of Ar–Au–Ar intermediates, via systematic modulation of the length of aryl-aryl linkage, but also the ability to arylate neutral and electron-poor arenes - substrates that do not react at all in the intermolecular process. Rendering the arylation intramolecular also results in phenomenologically simpler reaction kinetics, and overall these features have facili-tated a detailed study of linear free energy relationships, kinetic isotope effects, and the first quantitative experimental data on the effects of aryl electron-demand and conformational freedom on the rate of reductive elimination from diaryl gold(III) species. The turnover-limiting step for the formation of a series of fluorene derivatives is sensitive to the electronics of the arene and changes from reductive elimination to π-complexation for arenes bearing strongly electron-withdrawing substitu-ents (σ >0.43). Reductive elimination is accelerated by electron-donating substituents (□ = -2.0) on one or both rings, with the individual σ-values being additive in nature. Longer and more flexible tethers between the two aryl rings results in faster reductive elimination from Ar-Au(X)-Ar, and to the π-complexation of the arene by Ar-AuX2 becoming the turnover-limiting step
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