405 research outputs found

    Induced innovation in energy technologies and systems: a review of evidence and potential implications for CO2 mitigation

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    We conduct a systematic, interdisciplinary review of empirical literature assessing evidence on induced innovation in energy and related technologies. We explore links between demand-drivers (both market-wide and targeted); indicators of innovation (principally, patents); and outcomes (cost reduction, efficiency, and multi-sector/macro consequences). We build on existing reviews in different fields and assess over 200 papers containing original data analysis. Papers linking drivers to patents, and indicators of cumulative capacity to cost reductions (experience curves), dominate the literature. The former does not directly link patents to outcomes; the latter does not directly test for the causal impact of on cost reductions). Diverse other literatures provide additional evidence concerning the links between deployment, innovation activities, and outcomes. We derive three main conclusions. (1) Demand-pull forces enhance patenting; econometric studies find positive impacts in industry, electricity and transport sectors in all but a few specific cases. This applies to all drivers - general energy prices, carbon prices, and targeted interventions that build markets. (2) Technology costs decline with cumulative investment for almost every technology studied across all time periods, when controlled for other factors. Numerous lines of evidence point to dominant causality from at-scale deployment (prior to self-sustaining diffusion) to cost reduction in this relationship. (3) Overall Innovation is cumulative, multi-faceted, and self-reinforcing in its direction (path-dependent). We conclude with brief observations on implications for modeling and policy. In interpreting these results, we suggest distinguishing the economics of active deployment, from more passive diffusion processes, and draw the following implications. There is a role for policy diversity and experimentation, with evaluation of potential gains from innovation in the broadest sense. Consequently, endogenising innovation in large-scale models is important for deriving policy-relevant conclusions. Finally, seeking to relate quantitative economic evaluation to the qualitative socio-technical transitions literatures could be a fruitful area for future research

    The homocysteine controversy

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    Mild to moderate hyperhomocysteinemia has been identified as a strong predictor of cardiovascular disease, independent from classical atherothrombotic risk factors. In the last decade, a number of large intervention trials using B vitamins have been performed and have shown no benefit of homocysteine-lowering therapy in high-risk patients. In addition, Mendelian randomization studies failed to convincingly demonstrate that a genetic polymorphism commonly associated with higher homocysteine levels (methylenetetrahydrofolate reductase 677 C>T) is a risk factor for cardiovascular disease. Together, these findings have cast doubt on the role of homocysteine in cardiovascular disease pathogenesis, and the homocysteine hypothesis has turned into a homocysteine controversy. In this review, we attempt to find solutions to this controversy. First, we explain that the Mendelian randomization analyses have limitations that preclude final conclusions. Second, several characteristics of intervention trials limit interpretation and generalizability of their results. Finally, the possibility that homocysteine lowering is in itself beneficial but is offset by adverse side effects of B vitamins on atherosclerosis deserves serious attention. As we explain, such side effects may relate to direct adverse effects of the B-vitamin regimen (in particular, the use of high-dose folic acid) or to proinflammatory and proproliferative effects of B vitamins on advanced atherosclerotic lesions

    Indium contamination from the indium-tin-oxide electrode in polymer light-emitting diodes

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    We have found that polymer light-emitting diodes (LEDs) contain high concentrations of metal impurities prior to operation. Narrow peaks in the electroluminescence spectrum unambiguously demonstrate the presence of atomic indium and aluminum. Rutherford backscattering spectroscopy (RBS) and x-ray photoelectron spectroscopy (XPS) depth profiling data corroborate this result. An average indium concentration of 5 x 10(19)atoms/cm(3) originating from the indium-tin-oxide (ITO) electrode has been found in the polymer layer. (C) 1996 American Institute of Physics

    Modeling and Simulation of Multi-Lane Traffic Flow

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    A most important aspect in the field of traffic modeling is the simulation of bottleneck situations. For their realistic description a macroscopic multi-lane model for uni-directional freeways including acceleration, deceleration, velocity fluctuations, overtaking and lane-changing maneuvers is systematically deduced from a gas-kinetic (Boltzmann-like) approach. The resulting equations contain corrections with respect to previous models. For efficient computer simulations, a reduced model delineating the coarse-grained temporal behavior is derived and applied to bottleneck situations.Comment: For related work see http://www.theo2.physik.uni-stuttgart.de/helbing.htm

    Theoretical models of nonlinear effects in two-component cooperative supramolecular copolymerizations

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    The understanding of multi-component mixtures of self-assembling molecules under thermodynamic equilibrium can only be advanced by a combined experimental and theoretical approach. In such systems, small differences in association energy between the various components can be significantly amplified at the supramolecular level via intricate nonlinear effects. Here we report a theoretical investigation of two-component, self-assembling systems in order to rationalize chiral amplification in cooperative supramolecular copolymerizations. Unlike previous models based on theories developed for covalent polymers, the models presented here take into account the equilibrium between the monomer pool and supramolecular polymers, and the cooperative growth of the latter. Using two distinct methodologies, that is, solving mass-balance equations and stochastic simulation, we show that monomer exchange accounts for numerous unexplained observations in chiral amplification in supramolecular copolymerization. In analogy with asymmetric catalysis, amplification of chirality in supramolecular polymers results in an asymmetric depletion of the enantiomerically related monomer pool

    International comparisons of sectoral energy- and labour-productivity performance. Stylised facts and decomposition of trends

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    This paper addresses the interplay between economic growth, energy use, change in sectoral composition and technological change, by exploring trends in energy- and labour productivity development for 14 OECD countries and four sectors over the period 1970-1997. A cross-country decomposition analysis reveals that in some countries structural changes contributed considerably to macroeconomic energy-productivity growth while in other countries they partly offset energy-efficiency improvements. In contrast, structural changes only play a minor role in explaining macroeconomic labour-productivity developments. We also find labour productivity growth to be higher on average than energy productivity growth. Over time, this bias towards labour productivity growth is increasing in Transport, Agriculture and Manufacturing, while it is decreasing in Services

    Decoupling Economic Growth and Energy Use. An Empirical Cross-Country Analysis for 10 Manufacturing Sectors

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    This paper provides an empirical analysis of decoupling economic growth and energy use and its various determinants by exploring trends in energy- and labour productivity across 10 manufacturing sectors and 14 OECD countries for the period 1970-1997. We explicitly aim to trace back aggregate developments in the manufacturing sector to developments at the level of individual subsectors. A cross-country decomposition analysis reveals that in some countries structural changes contributed considerably to aggregate manufacturing energy-productivity growth and, hence, to decoupling, while in other countries they partly offset energy-efficiency improvements. In contrast, structural changes only play a minor role in explaining aggregate manufacturing labour-productivity developments. Furthermore, we find labour-productivity growth to be higher on average than energy-productivity growth. Over time, this bias towards labour-productivity growth is increasing in the aggregate manufacturing sector, while it is decreasing in most manufacturing subsectors

    Economic Challenges in the Anthropocene

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    The evolution during the Anthropocene is analyzed through the interaction between economic and technological development, characterized by the role of fossil fuels and by the progressive dominance of those with a higher energy and density power. The challenge is how to make the rising demand for economic growth, mainly coming from developing and emerging countries, compatible with the sustainability of the processes concerning the Earth system. Mainly by focusing on the energy-environment challenge, it is claimed that the required technological breakthrough will not be possible without an appropriate combination of environmental and innovation policies. The big size of the needed investments in a context of limited financial resources asks for a strong support and definition of precise priorities by the governments. A strong help will come from a cultural change able to determine a more sustainable demand for goods and services and a new system of social norms

    The role of cardiovascular magnetic resonance imaging and computed tomography angiography in suspected non-ST-elevation myocardial infarction patients:Design and rationale of the CARdiovascular Magnetic rEsoNance imaging and computed Tomography Angiography (CARMENTA) trial

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    BackgroundAlthough high-sensitivity cardiac troponin (hs-cTn) substantially improves the early detection of myocardial injury, it lacks specificity for acute myocardial infarction (MI). In suspected non–ST-elevation MI, invasive coronary angiography (ICA) remains necessary to distinguish between acute MI and noncoronary myocardial disease (eg, myocarditis), unnecessarily subjecting the latter to ICA and associated complications. This trial investigates whether implementing cardiovascular magnetic resonance (CMR) or computed tomography angiography (CTA) early in the diagnostic process may help to differentiate between coronary and noncoronary myocardial disease, thereby preventing unnecessary ICA.Study DesignIn this prospective, single-center, randomized controlled clinical trial, 321 consecutive patients with acute chest pain, elevated hs-cTnT, and nondiagnostic electrocardiogram are randomized to 1 of 3 strategies: (1) CMR, or (2) CTA early in the diagnostic process, or (3) routine clinical management. In the 2 investigational arms of the study, results of CMR or CTA will guide further clinical management. It is expected that noncoronary myocardial disease is detected more frequently after early noninvasive imaging as compared with routine clinical management, and unnecessary ICA will be prevented. The primary end point is the total number of patients undergoing ICA during initial admission. Secondary end points are 30-day and 1-year clinical outcome (major adverse cardiac events and major procedure-related complications), time to final diagnosis, quality of life, and cost-effectiveness.ConclusionThe CARMENTA trial investigates whether implementing CTA or CMR early in the diagnostic process in suspected non–ST-elevation MI based on elevated hs-cTnT can prevent unnecessary ICA as compared with routine clinical management, with no detrimental effect on clinical outcome
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