1,556 research outputs found

    Expectations for a New Climate Agreement

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    With the objective of stimulating timely and open discussion of the current attempt to formulate a new climate agreement—to be reached at the 21st meeting of the Conference of Parties (COP-21) in Paris during November of 2015—analysis is conducted of the expected developments in the lead-up negotiations. Based on the assumption that the architecture of the agreement will likely involve voluntary pledges and ex-post review (akin to the Copenhagen Accord), the domestic policies and measures expected to underlie national negotiating positions are described. Applying a global economic model, the effect of these Nationally Determined Contributions (NDCs) on global greenhouse gas emissions is assessed. The analysis shows that an agreement likely achievable at COP-21 will succeed in a useful bending the curve of global emissions. The likely agreement will not, however, produce global emissions within the window of paths to 2050 that are consistent with frequently proposed climate goals, raising questions about follow-up steps in the development of a climate regime.The Emissions Prediction and Policy Analysis (EPPA) model is supported by a consortium of government, industry and foundation sponsors of the MIT Joint Program on the Science and Policy of Global Change, including U.S. Department of Energy, Office of Science (DE-FG02-94ER61937)

    Launching a New Climate Regime

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    At the 2015 UN Framework Convention on Climate Change (UNFCCC) meeting in Paris, participants in a new international climate agreement will volunteer Nationally Determined Contributions to emissions reductions. To put the planet on a path to declared temperature goals, the growth of global greenhouse gas emissions must cease, and begin to decline, by 2035 to 2040; however, the expected contributions do not yield results consistent with this timeline. Three achievements in Paris and follow-on activities are then crucial components of the new climate regime: a robust system of review with widely accepted measures of national effort; an established, durable plan of future pledge cycles; and increased financial support for the mitigation efforts of less developed countries. The MIT Economic Projection and Policy Analysis (EPPA) model is applied to assess emissions outcomes of expected pledges and national performances in meeting them, and to elaborate the components of a successful launch.The Joint Program on the Science and Policy of Global Change is funded by a consortium of government, industrial, and foundation sponsors (for the complete list see: http://globalchange.mit.edu/sponsors/all). Support from the U.S. Federal Government in the past three years was received from the U.S. Department of Energy, Office of Science under grants DE-FG02-94ER61937, DE-SC0007114, DE-FG02-08ER64597; the U.S. Department of Energy, Oak Ridge National Laboratory under subcontract 4000109855; the U.S. Department of Agriculture under grant 58-6000-2-0099; the U.S. Energy Information Administration under grant DE-EI0001908; the U.S. Environmental Protection Agency under grants XA-83505101-0, XA-83600001-1, and RD-83427901-0; the U.S. Federal Aviation Administration under agreement 09-C-NE-MIT; the U.S. National Aeronautics and Space Administration under grants NNX13AH91A, NNX11AN72G, and subawards 4103-60255 and 4103-30368; the U.S. National Renewable Energy Laboratory under grant UGA-0-41029-15; the U.S. National Science Foundation under grants OCE-1434007, IIS-1028163, EF-1137306, AGS-1216707, ARC-1203526, AGS-1339264, AGS-0944121, and sub-awards UTA08.950 and 1211086Z1; the U.S. Department of Transportation under grant DTRT57-10-C-10015; the U.S. Department of Commerce, National Oceanic and Atmospheric Administration under grant NA13OAR4310084

    Transparency in the Paris Agreement

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    Establishing a credible and effective transparency system will be both crucial and challenging for the climate regime based on the pledge and review process established in the Paris Agreement. The Agreement provides for review of achievements under national pledges (Nationally Determined Contributions, or NDCs), but much of this information will become available only well after key steps in the launch of this latest attempt to control human influence on the climate. Still, in these early years, information and understanding of individual and collective performance, and of relative national burdens under the NDCs, will play an important role in the success or failure of the Agreement. However, because of the phasing of various steps in the 5-year cycles under the Agreement and the unavoidable delays of two or more years to produce and review government reports, the Climate Convention and other intergovernmental institutions are ill-suited to carry out timely analyses of progress. Consequently, in advance of formal procedures, academic and other non-governmental groups are going to provide analyses based on available data and their own methodologies. We explore this transparency challenge, using the MIT Economic Projection and Policy Analysis (EPPA) model, to construct sample analyses, and consider ways that efforts outside official channels can make an effective contribution to the success of the Agreement.We gratefully acknowledge the financial support for this work provided by the MIT Joint Program on the Science and Policy of Global Change through a consortium of industrial and foundation sponsors and Federal awards, including the U.S. Department of Energy, Office of Science under DE-FG02-94ER61937 and the U.S. Environmental Protection Agency under XA-83600001-1. For a complete list of sponsors and the U.S. government funding sources, please visit http://globalchange.mit.edu/sponsors/all

    Regulatory Control of Vehicle and Power Plant Emissions: How Effective and at What Cost?

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    Passenger vehicles and power plants are major sources of greenhouse gas emissions. While economic analyses generally indicate that a broader market-based approach to greenhouse gas reduction would be less costly and more effective, regulatory approaches have found greater political success. Vehicle efficiency standards have a long history in the U.S and elsewhere, and the recent success of shale gas in the U.S. leads to a focus on coal–gas fuel switching as a way to reduce power sector emissions. We evaluate a global regulatory regime that replaces coal with natural gas in the electricity sector and imposes technically achievable improvements in the efficiency of personal transport vehicles. Its performance and cost are compared with other scenarios of future policy development including a no policy world, achievements under the Copenhagen accord, and a price-based policy to reduce global emissions by 50% by 2050. The assumed regulations applied globally achieve a global emissions reduction larger than projected for the Copenhagen agreements, but they do not prevent global GHG emissions from continuing to grow, and the reduction in emissions is achieved at a high cost compared to a price-based policy. Diagnosis of the reasons for the limited yet high-cost performance reveals influences including the partial coverage of emitting sectors, small or no influence on the demand for emissions-intensive products, leakage when a reduction in fossil use in the covered sectors lowers the price to others, and the partial coverage of GHGs.We thank BP for their support of this study. The MIT Integrated Global System Model (IGSM) and its economic component used in the analysis, the Emissions Prediction and Policy Analysis (EPPA model, are supported by a consortium of government, industry and foundation sponsors of the MIT Joint Program on the Science and Policy of Global Change, including U.S. Department of Energy, Office of Science (DE-FG02-94ER61937). For a complete list of sponsors see http://globalchange.mit.edu/sponsors/current.html

    A Comparison of the Backpropagation and Recursive Prediction Error Algorithms for Training Neural Networks.

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    A new recursive prediction error routine is compared with the backpropagation method of training neural networks. Results based on simulated systems, the prediction of Canadian Lynx data and the modelling of an automotive diesel engine indicate that the recursive prediction error algorithm is far superior to backpropagation

    Characterization of latex allergenic components by capillary zone electrophoresis and N-terminal sequence analysis

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    In a previous study, protein components purified from latex gloves that elicited allergenic reactions were characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and yielded apparent molecular weights of 14, 22, 30, 34, 46, and 58 kD, These allergenic components were isolated for further characterization by capillary zone electrophoresis and N-terminal amino acid sequence analysis. These components all migrated at approximately 25 and 35 min on capillary zone electrophoresis, Diode array spectral analysis detected indistinguishable characteristics between these two protein peaks, In addition, complex formation of these components with patients' immunoglobulin was demonstrated by capillary zone electrophoresis. Analysis of components separated by SDS-PAGE on a polyvinylidene difluoride membrane showed that the first 13 residues were identical to the sequence of hevein, Based on the criteria of charge-to-mass ratio and N-terminal amino acid sequence, our results suggest that these components of latex proteins are similar in the primary structure

    Temperature dependence of Vortex Charges in High Temperature Superconductors

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    Using a model Hamiltonian with d-wave superconductivity and competing antiferromagnetic (AF) interactions, the temperature (T) dependence of the vortex charge in high T_c superconductors is investigated by numerically solving the Bogoliubov-de Gennes equations. The strength of the induced AF order inside the vortex core is T dependent. The vortex charge could be negative when the AF order with sufficient strength is present at low temperatures. At higher temperatures, the AF order may be completely suppressed and the vortex charge becomes positive. A first order like transition in the T dependent vortex charge is seen near the critical temperature T_{AF}. For underdoped sample, the spatial profiles of the induced spin-density wave and charge-density wave orders could have stripe like structures at T < T_s, and change to two-dimensional isotropic ones at T > T_s. As a result, a vortex charge discontinuity occurs at T_s.Comment: 5 pages, 5 figure

    Heavy Quarks on Anisotropic Lattices: The Charmonium Spectrum

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    We present results for the mass spectrum of ccˉc{\bar c} mesons simulated on anisotropic lattices where the temporal spacing ata_t is only half of the spatial spacing asa_s. The lattice QCD action is the Wilson gauge action plus the clover-improved Wilson fermion action. The two clover coefficients on an anisotropic lattice are estimated using mean links in Landau gauge. The bare velocity of light νt\nu_t has been tuned to keep the anisotropic, heavy-quark Wilson action relativistic. Local meson operators and three box sources are used in obtaining clear statistics for the lowest lying and first excited charmonium states of 1S0^1S_0, 3S1^3S_1, 1P1^1P_1, 3P0^3P_0 and 3P1^3P_1. The continuum limit is discussed by extrapolating from quenched simulations at four lattice spacings in the range 0.1 - 0.3 fm. Results are compared with the observed values in nature and other lattice approaches. Finite volume effects and dispersion relations are checked.Comment: 36 pages, 6 figur

    The K\"ahler-Ricci flow with positive bisectional curvature

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    We show that the K\"ahler-Ricci flow on a manifold with positive first Chern class converges to a K\"ahler-Einstein metric assuming positive bisectional curvature and certain stability conditions.Comment: 15 page

    Transition from fractal to non-fractal scalings in growing scale-free networks

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    Real networks can be classified into two categories: fractal networks and non-fractal networks. Here we introduce a unifying model for the two types of networks. Our model network is governed by a parameter qq. We obtain the topological properties of the network including the degree distribution, average path length, diameter, fractal dimensions, and betweenness centrality distribution, which are controlled by parameter qq. Interestingly, we show that by adjusting qq, the networks undergo a transition from fractal to non-fractal scalings, and exhibit a crossover from `large' to small worlds at the same time. Our research may shed some light on understanding the evolution and relationships of fractal and non-fractal networks.Comment: 7 pages, 3 figures, definitive version accepted for publication in EPJ
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