1,724 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

    Some Comments on an MeV Cold Dark Matter Scenario

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    We discuss several aspects of astroparticle physics pertaining to a new model with MeV cold dark matter particles, which annihilate to electron-positron pairs in a manner yielding the correct CDM density required today, and explaining the enhanced electron-positron annihilation line from the center of the Galaxy. We note that the mass of the vector meson mediating the annihilations, should exceed the mass of CDM particle, and comment on possible enhancement due to CDM clustering, on the detectability of the new CDM, and on particle physics models incorporating this scenario.Comment: 13 pages, 2 figures. v2 - Added some remarks regarding a more stringent mass bound. References added, some typos corrected. v3 - Added a comment regarding the invalidity of perturbative calculation in the case of a very small coupling g'. Removed the comment regarding the smallness of the angular width of the 511 keV lin

    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

    Inspection System for Benchmarking of Perceived and Technical Characteristics of Surfaces

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    Haptic perception of texture is an important tool in the evaluation of products such as smartphones, automobiles, kitchen appliances etc. Successful companies thus aim at actively designing the haptic impression of their products to the haptic preferences of their customers. However doing so requires information as to how comparable product surfaces are perceived by the customer and how these surfaces can be characterized technically. The perceived haptic impression of an object can be estimated using human studies, whereas its technical characteristics can be measured. However, direct correlation between perceived and standard measurements often shows poor significance, thus perceived haptic impression can not be simply derived from standard measurements. It remains to be analysed, if alternative measurements can provide a more significant characterization of surfaces in terms of their perceived haptic impression. To allow a more efficient estimation of the perceived impression of an object, an automatic inspection system is presented. This system consists of a force controlled robot driving a biomimetic sensor by the company Syntouch, providing a vibration signal during traverse over a surface. The paper presents results of a study to correlate the sensor signals to the perceived roughness of different surfaces evaluated by human subjects and set this in comparison to a correlation between standard roughness values and the perceived roughness

    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

    HIV Vulnerability in Out-of-School Adolescents and Youth in Yunnan, China

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    This study investigated multiple aspects of vulnerability to HIV in out-of-school adolescents and youth in Yunnan Province, a high HIV risk region in China. The findings show that socially disadvantaged adolescents and youth were overrepresented in the out-of-school young people in Yunnan. The out-of-school young people in Yunnan exhibited 1) limited knowledge about HIV transmission and prevention, 2) a high prevalence of unprotected sexual activity, 3) high exposure to illicit drugs and alcohol use and a high prevalence of drug use in themselves, and 4) limited access to health services. There is an indication of higher exposure to risk behaviours in the younger age group. The study population used multiple media, particularly television, internet and radio, to obtain information about HIV transmission and pre- vention, particularly in the younger age group. These media may be an effective way of reaching this population in fu- ture HIV education and prevention programs in the region

    On the progenitors of millisecond pulsars by the recycling evolutionary channel

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    The recycling model suggested that low-mass X-ray binaries (LMXBs) could evolve into binary millisecond pulsars (BMSPs). In this work, we attempt to investigate the progenitor properties of BMSPs formed by the recycling evolutionary channel, and if sub-millisecond pulsars can be produced by this channel. Using Eggleton's stellar evolution code, considering that the dead pulsars can be spun up to a short spin period by the accreting material and angular momentum from the donor star, we have calculated the evolution of close binaries consisting of a neutron star and a low-mass main-sequence donor star, and the spin evolution of NSs. In calculation, some physical process such as the thermal and viscous instability of a accretion disk, propeller effect, and magnetic braking are included. Our calculated results indicate that, all LMXBs with a low-mass donor star of 1.0 - 2.0 M⊙M_\odot and a short orbital period (\la 3-4 \rm d) can form millisecond pulsars with a spin period less than 10 ms. However, it is difficult to produce sub-millisecond pulsars by this evolutionary channel. In addition, our evolutionary scenario cannot account for the existence of BMSPs with a long orbital period (P_{\rm orb}\ga 70-80\rm d).Comment: 7 pages,5 figures, MNRAS in pres
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