1,100 research outputs found

    Second best toll and capacity optimisation in network: solution algorithm and policy implications

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    This paper looks at the first and second-best jointly optimal toll and road capacity investment problems from both policy and technical oriented perspectives. On the technical side, the paper investigates the applicability of the constraint cutting algorithm for solving the second-best problem under elastic demand which is formulated as a bilevel programming problem. The approach is shown to perform well despite several problems encountered by our previous work in Shepherd and Sumalee (2004). The paper then applies the algorithm to a small sized network to investigate the policy implications of the first and second-best cases. This policy analysis demonstrates that the joint first best structure is to invest in the most direct routes while reducing capacities elsewhere. Whilst unrealistic this acts as a useful benchmark. The results also show that certain second best policies can achieve a high proportion of the first best benefits while in general generating a revenue surplus. We also show that unless costs of capacity are known to be low then second best tolls will be affected and so should be analysed in conjunction with investments in the network

    Policy insights and modelling challenges: The case of passenger car powertrain technology transition in the European Union

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    Purpose: We are interested in what policy insights can be transferred from EU countries that have been most successful in introducing EVs to those that are debating policy options. As we use a model to explore this, we are also interested in the application of modelling, seeking to understand if real world policies and results can be replicated in a model and, more generally, the challenges to the use of modelling in policy appraisal. Methods: We use the EC-JRC Powertrain Technology Transition Market Agent Model (PTTMAM), a system dynamics model based around the interactions of conceptual market agent groups in the EU. We perform iterative scenario tests to replicate the policies carried out in the Netherlands and the UK in recent years in an attempt to achieve similar results in EV sales. We then transfer the policy scenarios to other EU member states and assess the transferability of the policies. Results: Reasonable approximations of the Netherlands and UK EV policies and sales were achieved and implemented in other EU member states. Conclusion: We find that the PTTMAM is fit-for-purpose and can replicate successful policies to a certain degree. Policy success is sensitive to country specific conditions, and a system dynamics model like the PTTMAM can help identify which conditions react to which policy stimulus. There are challenges to modelling in policy appraisal, such as the subjectivity of the modeller and flexibility to specific conditions, which must be kept transparent for the model to be a relevant tool for policy making

    Subclinical thyroid dysfunction and cognitive decline in old age

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    <p>Background: Subclinical thyroid dysfunction has been implicated as a risk factor for cognitive decline in old age, but results are inconsistent. We investigated the association between subclinical thyroid dysfunction and cognitive decline in the PROspective Study of Pravastatin in the Elderly at Risk (PROSPER).</p> <p>Methods: Prospective longitudinal study of men and women aged 70–82 years with pre-existing vascular disease or more than one risk factor to develop this condition (N = 5,154). Participants taking antithyroid medications, thyroid hormone supplementation and/or amiodarone were excluded. Thyroid function was measured at baseline: subclinical hyper- and hypothyroidism were defined as thyroid stimulating hormones (TSH) <0.45 mU/L or >4.50 mU/L respectively, with normal levels of free thyroxine (FT4). Cognitive performance was tested at baseline and at four subsequent time points during a mean follow-up of 3 years, using five neuropsychological performance tests.</p> <p>Results: Subclinical hyperthyroidism and hypothyroidism were found in 65 and 161 participants, respectively. We found no consistent association of subclinical hyper- or hypothyroidism with altered cognitive performance compared to euthyroid participants on the individual cognitive tests. Similarly, there was no association with rate of cognitive decline during follow-up.</p> <p>Conclusion: We found no consistent evidence that subclinical hyper- or hypothyroidism contribute to cognitive impairment or decline in old age. Although our data are not in support of treatment of subclinical thyroid dysfunction to prevent cognitive dysfunction in later life, only large randomized controlled trials can provide definitive evidence.</p&gt

    Subclinical thyroid dysfunction and cognitive decline in old age

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    <p>Background: Subclinical thyroid dysfunction has been implicated as a risk factor for cognitive decline in old age, but results are inconsistent. We investigated the association between subclinical thyroid dysfunction and cognitive decline in the PROspective Study of Pravastatin in the Elderly at Risk (PROSPER).</p> <p>Methods: Prospective longitudinal study of men and women aged 70–82 years with pre-existing vascular disease or more than one risk factor to develop this condition (N = 5,154). Participants taking antithyroid medications, thyroid hormone supplementation and/or amiodarone were excluded. Thyroid function was measured at baseline: subclinical hyper- and hypothyroidism were defined as thyroid stimulating hormones (TSH) <0.45 mU/L or >4.50 mU/L respectively, with normal levels of free thyroxine (FT4). Cognitive performance was tested at baseline and at four subsequent time points during a mean follow-up of 3 years, using five neuropsychological performance tests.</p> <p>Results: Subclinical hyperthyroidism and hypothyroidism were found in 65 and 161 participants, respectively. We found no consistent association of subclinical hyper- or hypothyroidism with altered cognitive performance compared to euthyroid participants on the individual cognitive tests. Similarly, there was no association with rate of cognitive decline during follow-up.</p> <p>Conclusion: We found no consistent evidence that subclinical hyper- or hypothyroidism contribute to cognitive impairment or decline in old age. Although our data are not in support of treatment of subclinical thyroid dysfunction to prevent cognitive dysfunction in later life, only large randomized controlled trials can provide definitive evidence.</p&gt

    Combined written and oral information prior to gastrointestinal endoscopy compared with oral information alone: a randomized trial

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    BACKGROUND: Little is known about how to most effectively deliver relevant information to patients scheduled for endoscopy. METHODS: To assess the effects of combined written and oral information, compared with oral information alone on the quality of information before endoscopy and the level of anxiety. We designed a prospective study in two Swiss teaching hospitals which enrolled consecutive patients scheduled for endoscopy over a three-month period. Patients were randomized either to receiving, along with the appointment notice, an explanatory leaflet about the upcoming examination, or to oral information delivered by each patient's doctor. Evaluation of quality of information was rated on scales between 0 (none received) and 5 (excellent). The analysis of outcome variables was performed on the basis of intention to treat-analysis. Multivariate analysis of predictors of information scores was performed by linear regression analysis. RESULTS: Of 718 eligible patients 577 (80%) returned their questionnaire. Patients who received written leaflets (N = 278) rated the quality of information they received higher than those informed verbally (N = 299), for all 8 quality-of-information items. Differences were significant regarding information about the risks of the procedure (3.24 versus 2.26, p < 0.001), how to prepare for the procedure (3.56 versus 3.23, p = 0.036), what to expect after the procedure (2.99 versus 2.59, p < 0.001), and the 8 quality-of-information items (3.35 versus 3.02, p = 0.002). The two groups reported similar levels of anxiety before procedure (p = 0.66), pain during procedure (p = 0.20), tolerability throughout the procedure (p = 0.76), problems after the procedure (p = 0.22), and overall rating of the procedure between poor and excellent (p = 0.82). CONCLUSION: Written information led to more favourable assessments of the quality of information and had no impact on patient anxiety nor on the overall assessment of the endoscopy. Because structured and comprehensive written information is perceived as beneficial by patients, gastroenterologists should clearly explain to their patients the risks, benefits and alternatives of endoscopic procedures. Trial registration: Current Controlled trial number: ISRCTN34382782

    An FPGA-based track finder for the L1 trigger of the CMS experiment at the high luminosity LHC

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    A new tracking system is under development for operation in the CMS experiment at the High Luminosity LHC. It includes an outer tracker which will construct stubs, built by correlating clusters in two closely spaced sensor layers for the rejection of hits from low transverse momentum tracks, and transmit them off-detector at 40 MHz. If tracker data is to contribute to keeping the Level-1 trigger rate at around 750 kHz under increased luminosity, a crucial component of the upgrade will be the ability to identify tracks with transverse momentum above 3 GeV/c by building tracks out of stubs. A concept for an FPGA-based track finder using a fully time-multiplexed architecture is presented, where track candidates are identified using a projective binning algorithm based on the Hough Transform. A hardware system based on the MP7 MicroTCA processing card has been assembled, demonstrating a realistic slice of the track finder in order to help gauge the performance and requirements for a full system. This paper outlines the system architecture and algorithms employed, highlighting some of the first results from the hardware demonstrator and discusses the prospects and performance of the completed track finder

    Measurement of Exclusive B Decays to Final States Containing a Charmed Baryon

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    Using data collected by the CLEO detector in the Upsilon(4S) region, we report new measurements of the exclusive decays of B mesons into final states of the type Lambda_c^+ p-bar n(pi), where n=0,1,2,3. We find signals in modes with one, two and three pions and an upper limit for the two body decay Lambda_c^+ pbar. We also make the first measurements of exclusive decays of B mesons to Sigma_c p-bar n(pi), where n=0,1,2. We find signals in modes with one and two pions and an upper limit for the two body decay Sigma_c p-bar. Measurements of these modes shed light on the mechanisms involved in B decays to baryons.Comment: 11 pages postscript, also available through http://w4.lns.cornell.edu/public/CLNS, submitted to PR

    Emulation of a prototype FPGA track finder for the CMS Phase-2 upgrade with the CIDAF emulation framework

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    The CMS collaboration is preparing a major upgrade of its detector, so it can operate during the high luminosity run of the LHC from 2026. The upgraded tracker electronics will reconstruct the trajectories of charged particles within a latency of a few microseconds, so that they can be used by the level-1 trigger. An emulation framework, CIDAF, has been developed to provide a reference for a proposed FPGA-based implementation of this track finder, which employs a Time-Multiplexed (TM) technique for data processing.The research leading to these results has received funding from the People Programme (Marie Curie Actions) of the European Unions Seventh Framework Programme FP7/2007- 2013/ under REA grant agreement n [317446] INFIERI “Intelligent Fast Interconnected and Efficient Devices for Frontier Exploitation in Research and Industry”. This work was supported in part by the the UK Science and Technology Facilities Council, we gratefully acknowledge their support

    Measurement of the Masses and Widths of the Sigma_c^++ and Sigma_c^0 Charmed Baryons

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    Using data recorded by the CLEO II and CLEO II.V detector configurations at CESR, we report new measurements of the masses of the Sigma_c^{++} and Sigma_c^0 charmed baryons, and the first measurements of their intrinsic widths. We find M(Sigma_c^{++}) - M(Lambda_c^+) = 167.4 +- 0.1 +- 0.2 MeV, Gamma(Sigma_c^{++}) = 2.3 +- 0.2 +- 0.3 MeV, and M(Sigma_c^0) - M(Lambda_c^+) = 167.2 +- 0.1 +- 0.2 MeV, Gamma(Sigma_c^0) = 2.5 +- 0.2 +- 0.3 MeV, where the uncertainties are statistical and systematic, respectively.Comment: 9 pages postscript, also available through http://w4.lns.cornell.edu/public/CLNS, submitted to PRD, Rapid Communications. Reference [13] correcte
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