9,735 research outputs found

    Curbside Recycling: Waste Resource or Waste of Resources?

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    In this paper, we estimate the social net benefits of curbside recycling. Benefits are estimated using survey data on household willingness to pay (WTP) from over 4,000 households across 40 western U.S. cities. We calibrate WTP for hypothetical bias using an experimental design that contrasts stated and revealed preferences. Cost estimates are compiled from previous studies by the U.S. Environmental Protection Agency, the Institute for Local Self Reliance, as well as from in-depth interviews with recycling coordinators in our sampled cities. Remarkably, we find that the estimated mean social net benefit of curbside recycling is almost exactly zero. Therefore, the decision of whether to implement or maintain a curbside recycling program (CRP) must be done on a city-by-city basis.curbside recycling, willingness to pay, social net benefits, hypothetical bias, calibration

    CURBSIDE RECYCLING: WASTE RESOURCE OR WASTE OF RESOURCES?

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    Replaced with revised version of paper 07/28/04.Environmental Economics and Policy, Public Economics,

    Cheap Talk Revisited: New Evidence from CVM

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    Two recent studies have shown that “cheap talk” is an effective means of eliminating positive hypothetical bias in experimental and field-auction settings. We further investigate the ability of cheap talk to mitigate positive hypothetical bias in a CVM phone survey administered to over 4,000 households. Positive hypothetical bias is detected in our data by contrasting revealed and stated preference information. However, a short, neutral cheap-talk script appears to exacerbate rather than mitigate the bias. Based on this and mixed evidence from earlier studies, we suggest caution in using cheap talk as an ex ante control for hypothetical bias.cheap talk, hypothetical bias, contingent valuation

    Estimating Hypothetical Bias in Economically Emergent Africa: A Generic Public Good Experiment

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    This paper reports results from a contingent valuation based public good experiment conducted in the African nation of Botswana. In a sample of university students, we find evidence that stated willingness to contribute to a public good in a hypothetical setting is higher than actual contribution levels. However, results from regression analysis suggest that this is true only in the second round of the experiment, when participants making actual contributions have learned to significantly lower their contribution levels. As globalization expands markets, and economies such as Botswana’s continue to modernize, there is a growing need to understand how hypothetical bias will influence the valuation of public goods.hypothetical bias, public good, willingness to pay, Botswana, Environmental Economics and Policy,

    Complementary transcriptomic, lipidomic, and targeted functional genetic analyses in cultured Drosophila cells highlight the role of glycerophospholipid metabolism in Flock House virus RNA replication

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    Abstract Background Cellular membranes are crucial host components utilized by positive-strand RNA viruses for replication of their genomes. Published studies have suggested that the synthesis and distribution of membrane lipids are particularly important for the assembly and function of positive-strand RNA virus replication complexes. However, the impact of specific lipid metabolism pathways in this process have not been well defined, nor have potential changes in lipid expression associated with positive-strand RNA virus replication been examined in detail. Results In this study we used parallel and complementary global and targeted approaches to examine the impact of lipid metabolism on the replication of the well-studied model alphanodavirus Flock House virus (FHV). We found that FHV RNA replication in cultured Drosophila S2 cells stimulated the transcriptional upregulation of several lipid metabolism genes, and was also associated with increased phosphatidylcholine accumulation with preferential increases in lipid molecules with longer and unsaturated acyl chains. Furthermore, targeted RNA interference-mediated downregulation of candidate glycerophospholipid metabolism genes revealed a functional role of several genes in virus replication. In particular, we found that downregulation of Cct1 or Cct2, which encode essential enzymes for phosphatidylcholine biosynthesis, suppressed FHV RNA replication. Conclusion These results indicate that glycerophospholipid metabolism, and in particular phosphatidylcholine biosynthesis, plays an important role in FHV RNA replication. Furthermore, they provide a framework in which to further explore the impact of specific steps in lipid metabolism on FHV replication, and potentially identify novel cellular targets for the development of drugs to inhibit positive-strand RNA viruses.http://deepblue.lib.umich.edu/bitstream/2027.42/78268/1/1471-2164-11-183.xmlhttp://deepblue.lib.umich.edu/bitstream/2027.42/78268/2/1471-2164-11-183-S3.XLShttp://deepblue.lib.umich.edu/bitstream/2027.42/78268/3/1471-2164-11-183-S2.XLShttp://deepblue.lib.umich.edu/bitstream/2027.42/78268/4/1471-2164-11-183.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/78268/5/1471-2164-11-183-S4.XLShttp://deepblue.lib.umich.edu/bitstream/2027.42/78268/6/1471-2164-11-183-S1.XLSPeer Reviewe

    Intercellular communication in normal and regenerating rat liver: a quantitative analysis

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    We have compared intercellular communication in the regenerating and normal livers of weanling rats. The electrophysiological studies were conducted at the edge of the liver, and we have found that here as elsewhere in the liver there is a dramatic decrease in the number and size of gap junctions during regeneration. The area of hepatocyte membrane occupied by gap junctions is reduced 100-fold 29-35 h after hepatectomy. By combining observations made with the scanning electron microscope with our freeze fracture data we have estimated the number of "communicating interfaces" (areas of contact between hepatocytes that include at least one gap junction) formed by hepatocytes in normal and regenerating liver. In normal liver a hepatocyte forms gap junctions with every hepatocyte it contacts (approximately 6). In regenerating liver a hepatocyte forms detectable gap junctions with, on average, only one other hepatocyte. Intercellular spread of fluorescent dye and electric current is reduced in regenerating as compared with normal liver. The incidence of electric coupling is reduced from 100% of hepatocyte pairs tested in control liver to 92% in regenerating liver. Analysis of the spatial dependence of electronic potentials indicates a substantial increase in intercellular resistance in regenerating liver. A quantitative comparison of our morphological and physiological data is complicated by tortuous pattern of current flow and by inhomogeneities in the liver during regeneration. Nevertheless we believe that our results are consistent with the hypothesis that gap junctions are aggregates of channels between cell interiors

    Scalable k-Means Clustering via Lightweight Coresets

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    Coresets are compact representations of data sets such that models trained on a coreset are provably competitive with models trained on the full data set. As such, they have been successfully used to scale up clustering models to massive data sets. While existing approaches generally only allow for multiplicative approximation errors, we propose a novel notion of lightweight coresets that allows for both multiplicative and additive errors. We provide a single algorithm to construct lightweight coresets for k-means clustering as well as soft and hard Bregman clustering. The algorithm is substantially faster than existing constructions, embarrassingly parallel, and the resulting coresets are smaller. We further show that the proposed approach naturally generalizes to statistical k-means clustering and that, compared to existing results, it can be used to compute smaller summaries for empirical risk minimization. In extensive experiments, we demonstrate that the proposed algorithm outperforms existing data summarization strategies in practice.Comment: To appear in the 24th ACM SIGKDD International Conference on Knowledge Discovery & Data Mining (KDD

    Working with the Revenue code - 1967

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    https://egrove.olemiss.edu/aicpa_guides/2762/thumbnail.jp

    A Bioeconomic Model of the Great Salt Lake Watershed

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    We present a computable general equilibrium model of the interface between the Great Salt Lake (GSL) ecosystem and the regional economy that impacts the ecosystem. With respect to the ecosystem, the model treats the various representative species as net-energy maximizers and bases population dynamics on the period-by-period sizes of surplus net energy. Energy markets-where predators and prey exchange biomass-determine equilibrium energy prices. With respect to the regional economy, we model five production sectors (at the aggregate industry level)-brine cyst harvesters, the mineral-extraction industry, agriculture, recreation, and a composite-good industry-as well as the household sector. By performing dynamic simulations of the joint ecosystem-regional economy model, we isolate the effects of period-byperiod stochastic changes in salinity levels and an initial shock to species-population levels on the ecological and economic variables of the model
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