1,802 research outputs found

    Technology and Technical Change in the MIT EPPA Model

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    Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).Potential technology change has a strong influence on projections of greenhouse gas emissions and costs of control, and computable general equilibrium (CGE) models are a common device for studying these phenomena. Using the MIT Emissions Prediction and Policy Analysis (EPPA) model as an example, two ways of representing technology in these models are discussed: the sector-level description of production possibilities founded on social accounting matrices and elasticity estimates, and sub-models of specific supply or end-use devices based on engineering-process data. A distinction is made between exogenous and endogenous technical change, and it is shown how, because of model structure and the origin of key parameters, such models naturally include shifts in production process that reflect some degree of endogenous technical change. As a result, the introduction of explicit endogenous relations should be approached with caution, to avoid double counting.The CGE model underlying this analysis was supported by the US Department of Energy, Office of Biological and Environmental Research [BER] (DE-FG02-94ER61937), the US Environmental Protection Agency (X-827703-01-0), the Electric Power Research Institute, and by a consortium of industry and foundation sponsor

    The role of network density and betweenness centrality in diffusing new venture legitimacy: an epidemiological approach

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    To survive and grow, new ventures must establish initial legitimacy, and subsequently diffuse this legitimacy through a given population. While the notion of initial legitimacy has received substantial attention in the recent literature, diffusion has not. This work endeavors to outline the legitimacy diffusion process via drawing parallels with the field of epidemiology. Ultimately, to effectively diffuse legitimacy (and grow) a firm must gain positive judgments of appropriateness from members of a given network. Importantly, as with diseases, the characteristics of the network are critical to the diffusion process. A relatively dense network is posited to invoke a normative evaluation process by its members, and can be difficult for new ventures to access, but subsequent diffusion of new venture legitimacy can be rapid. A less dense network, on the other hand, is posited to invoke a pragmatic evaluation process by its members, and is likely easier for new ventures to access initially, but may result in lower levels of new venture legitimacy diffusion in the long run. Theoretical and practical implications are discussed

    Editorial: small scale spatial and temporal patterns in particles, plankton, and other organisms

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    © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nayak, A. R., Jiang, H., Byron, M. L., Sullivan, J. M., McFarland, M. N., & Murphy, D. W. Editorial: small scale spatial and temporal patterns in particles, plankton, and other organisms. Frontiers in Marine Science, 8, (2021): 669530, https://doi.org/10.3389./fmars.2021.669530Scientists have long known that small-scale interactions of aquatic particles, plankton, and other organisms with their immediate environment play an important role in diverse research areas, including marine ecology, ocean optics, and climate change (Guasto et al., 2012; Prairie et al., 2012). Typically, the distribution of particles and other organisms in the water column tends to be quite “patchy,” i.e., non-homogeneous, both spatially and temporally (Durham and Stocker, 2012). Patchiness can manifest itself through well-known phenomena such as harmful algal blooms (HABs), phytoplankton and zooplankton “thin layers,” deep scattering layers, and schooling of marine organisms such as krill and fish. This non-homogeneous distribution can significantly influence predator-prey encounters and outcomes, export fluxes, marine ecosystem health, and biological productivity (Sullivan et al., 2010; Durham et al., 2013). Thus, there is a continuing need to study and characterize the small-scale biological-physical interactions between particles/organisms and their local environment, as well as the scaled-up effects of these small-scale interactions on larger-scale dynamics. These studies are also directly linked to broader research topics listed as part of the future “grand challenges” in marine ecosystem ecology, as outlined in Borja et al. (2020).AN was supported through a National Academy of Sciences, Engineering, and Medicine (NASEM) Gulf Research Program (GRP) Early Career Research Fellowship and a faculty start-up grant at Florida Atlantic University. HJ was supported by US National Science Foundation awards (OCE-1559062 and IOS-1353937). MB was supported by a faculty start-up grant at Penn State University. AN, JS, and MM were supported by US National Science Foundation awards (OCE-1634053 and OCE-1657332). DM was supported by the US National Science Foundation (CBET-1846925)

    The MIT Emissions Prediction and Policy Analysis (EPPA) Model: Version 4

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    Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).The Emissions Prediction and Policy Analysis (EPPA) model is the part of the MIT Integrated Global Systems Model (IGSM) that represents the human systems. EPPA is a recursive-dynamic multi-regional general equilibrium model of the world economy, which is built on the GTAP dataset and additional data for the greenhouse gas and urban gas emissions. It is designed to develop projections of economic growth and anthropogenic emissions of greenhouse related gases and aerosols. The main purpose of this report is to provide documentation of a new version of EPPA, EPPA version 4. In comparison with EPPA3, it includes greater regional and sectoral detail, a wider range of advanced energy supply technologies, improved capability to represent a variety of different and more realistic climate policies, and enhanced treatment of physical stocks and flows of energy, emissions, and land use to facilitate linkage with the earth system components of the IGSM. Reconsideration of important parameters and assumptions led to some revisions in reference projections of GDP and greenhouse gas emissions. In EPPA4 the global economy grows by 12.5 times from 2000 to 2100 (2.5% per year) compared with an increase of 10.7 times (2.4% per year) in EPPA3. This is one of the important revisions that led to an increase in CO2 emissions to 25.7 GtC in 2100, up from 23 GtC in 2100 projected by EPPA3. There is considerable uncertainty in such projections because of uncertainty in various driving forces. To illustrate this uncertainty we consider scenarios where the global GDP grows 0.5% faster (slower) than the reference rate, and these scenarios result in CO2 emissions in 2100 of 34 (17) GtC. A sample greenhouse gas policy scenario that puts the world economy on a path toward stabilization of atmospheric CO2 at 550 ppmv is also simulated to illustrate the response of EPPA4 to a policy constraint.This research was supported by the U.S Department of Energy, U.S. Environmental Protection Agency, U.S. National Science Foundation, U.S. National Aeronautics and Space Administration, U.S. National Oceanographic and Atmospheric Administration; and the Industry and Foundation Sponsors of the MIT Joint Program on the Science and Policy of Global Change: Alstom Power (France), American Electric Power (USA), BP p.l.c. (UK/USA), Chevron Corporation (USA), CONCAWE (Belgium), DaimlerChrysler AG (Germany), Duke Energy (USA), J-Power (Japan), Electric Power Research Institute (USA), Electricité de France, ExxonMobil Corporation (USA), Ford Motor Company (USA), General Motors (USA), Murphy Oil Corporation (USA), Oglethorpe Power Corporation (USA), RWE Power (Germany), Shell Petroleum (Netherlands/UK), Southern Company (USA), Statoil ASA (Norway), Tennessee Valley Authority (USA), Tokyo Electric Power Company (Japan), Total (France), G. Unger Vetlesen Foundation (USA)

    Providing Spatial Data for Secondary Analysis: Issues and Current Practices Relating to Confidentiality

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    Spatially explicit data pose a series of opportunities and challenges for all the actors involved in providing data for long-term preservation and secondary analysis—the data producer, the data archive, and the data user. We report on opportunities and challenges for each of the three players, and then turn to a summary of current thinking about how best to prepare, archive, disseminate, and make use of social science data that have spatially explicit identification. The core issue that runs through the paper is the risk of the disclosure of the identity of respondents. If we know where they live, where they work, or where they own property, it is possible to find out who they are. Those involved in collecting, archiving, and using data need to be aware of the risks of disclosure and become familiar with best practices to avoid disclosures that will be harmful to respondents.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/60426/1/spatial data.confidentiality.fulltext.pd

    Bio-optical Properties of Cyanobacteria Blooms in Western Lake Erie

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    There is a growing use of remote sensing observations for detecting and quantifying freshwater cyanobacteria populations, yet the inherent optical properties of these communities in natural settings, fundamental to bio-optical algorithms, are not well known. Toward bridging this knowledge gap, we measured a full complement of optical properties in western Lake Erie during cyanobacteria blooms in the summers of 2013 and 2014. Our measurements focus attention on the optical uniqueness of cyanobacteria blooms, which have consequences for remote sensing and bio-optical modeling. We found the cyanobacteria blooms in the western basin during our field work were dominated by Microcystis, while the waters in the adjacent central basin were dominated by Planktothrix. Chlorophyll concentrations ranged from 1 to over 135 ÎĽg/L across the study area with the highest concentrations associated with Microcystis in the western basin. We observed large, amorphous colonial Microcystis structures in the bloom area characterized by high phytoplankton absorption and high scattering coefficients with a mean particle backscatter ratio at 443 nm \u3e 0.03, which is higher than other plankton types and more comparable to suspended inorganic sediments. While our samples contained mixtures of both, our analysis suggests high contributions to the measured scatter and backscatter coefficients from cyanobacteria. Our measurements provide new insights into the optical properties of cyanobacteria blooms, and indicate that current semi-analytic models are likely to have problems resolving a closed solution in these types of waters as many of our observations are beyond the range of existing model components. We believe that different algorithm or model approaches are needed for these conditions, specifically for phytoplankton absorption and particle backscatter components. From a remote sensing perspective, this presents a challenge not only in terms of a need for new algorithms, but also for determining when to apply the best algorithm for a given situation. These results are new in the sense that they represent a complete description of the optical properties of freshwater cyanobacteria blooms, and are likely to be representative of bloom conditions for other systems containing Microcystis cells and colonies

    Agribusiness Sheep Updates - 2004 - Part 1

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    Proceedings of the Agribusiness Sheep Updates - 2004 Forward Dr Mark Dolling Manager, Sheep Industries and Pasture, Department of Agriculture Western Australia Keynotes Australian Wool Innovation Limited DR LEN STEPHENS AUSTRALIAN WOOL INNOVATION LIMITED (AWI) Commercialisation of Sheepmeat Eating Quality Outcomes, David Thomason, General Manger Marketing Meat & livestock Australia Limited PLENARY The Fitness of the Future Merino, Norm Adams and Shimin Liu, CSIRO Livestock Industries Ovine Johne’s Disease – Managing the Disease, Managing the Issues, PETER BUCKMAN, CHIEF VETERINARY OFFICER, DEPARTMENT OF AGRICULTURE WESTERN AUSTRALIA Animal Welfare – Changes in Latitudes Changes in Attitudes, Michael Paton and Dianne Evans, Department of Agriculture Western Australian. Live Sheep Exports, JOHN EDWARDS. CHAIRMAN, WESTERN AUSTRALIAN LIVE SHEEP EXPORTERS ASSOCIATION MeCustomising to the Needs of the Customer – Insights from the New Zealand Merino Experience, DR SCOTT CHAMPION, RESEARCH, DEVELOPMENT AND PRODUCT INNOVATION MANAGER, THE NEW ZEALAND MERINO COMPANY LIMITED Agribusiness Sheep Updates Conference -Economic and Financial Market Update Alan Langford, Economist, BankWest Concurrent sessions - Meeting the Market Breeding Wool to Address Consumer Requirements in Fabrics A.C. SCHLINK CSIRO Livestock Industries, J.C. GREEFF AND M. E. LADYMAN Department of Agriculture Western Australia Fibre Contribution to Retail Demand for Knitwear Melanie LadymanA and John StantonAB ADepartment of Agriculture Western Australia and BCurtin University of Technology Sustainable Merino, is this the Future for Merino? Stuart Adams, iZWool International P/L Meeting lamb Market Specs from Crossbred Ewes Dr. Neal Fogarty, NSW Agriculture and the Australian Sheep Industry CRC Use of Serial Body Weight Measurements in Prime Lamb Finishing Systems Matthew Kelly, CSIRO Livestock Industries, James Skerritt, Ian McFarland Department of Agriculture Western Australia, Australian Sheep Industry CR

    “Biological Geometry Perception”: Visual Discrimination of Eccentricity Is Related to Individual Motor Preferences

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    In the continuum between a stroke and a circle including all possible ellipses, some eccentricities seem more “biologically preferred” than others by the motor system, probably because they imply less demanding coordination patterns. Based on the idea that biological motion perception relies on knowledge of the laws that govern the motor system, we investigated whether motorically preferential and non-preferential eccentricities are visually discriminated differently. In contrast with previous studies that were interested in the effect of kinematic/time features of movements on their visual perception, we focused on geometric/spatial features, and therefore used a static visual display.In a dual-task paradigm, participants visually discriminated 13 static ellipses of various eccentricities while performing a finger-thumb opposition sequence with either the dominant or the non-dominant hand. Our assumption was that because the movements used to trace ellipses are strongly lateralized, a motor task performed with the dominant hand should affect the simultaneous visual discrimination more strongly. We found that visual discrimination was not affected when the motor task was performed by the non-dominant hand. Conversely, it was impaired when the motor task was performed with the dominant hand, but only for the ellipses that we defined as preferred by the motor system, based on an assessment of individual preferences during an independent graphomotor task.Visual discrimination of ellipses depends on the state of the motor neural networks controlling the dominant hand, but only when their eccentricity is “biologically preferred”. Importantly, this effect emerges on the basis of a static display, suggesting that what we call “biological geometry”, i.e., geometric features resulting from preferential movements is relevant information for the visual processing of bidimensional shapes
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