4,319 research outputs found

    MULTIPLE AGENTS, AND AGRICULTURAL NONPOINT-SOURCE WATER POLLUTION CONTROL POLICIES

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    Assuming asymmetric information over farmer profits and zero transaction costs, prior literature has suggested that when regulating nonpoint source water pollution, a tax on management practices (inputs) can implement full-information allocations and is superior to a tax on estimated runoff. Using mechanism design theory under asymmetric information, this paper show that under the same assumptions, management practice taxes and taxes on estimated runoff are equally efficient.Environmental Economics and Policy,

    TRANSACTION COSTS AND AGRICULTURAL NONPOINT-SOURCE WATER POLLUTION CONTROL POLICIES

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    Mechanism design theory is used to develop the properties of optimal pollution control incentive schemes in the presence of adverse selection, moral hazard, and transaction costs. The model presented here shows (a) with no deadweight costs (transaction costs) , first-best allocations are always possible; (b) in the presence of transaction costs (caused by raising taxes), only second-best allocations are feasible; and (c) the conditions under which the optimal incentive scheme implementing second-best allocations will be a nonlinear tax, a standard(s), or a combination of both taxes and standard(s).Environmental Economics and Policy,

    FAMILIAR AND FAVORITE SITES IN A RANDOM UTILITY MODEL OF BEACH RECREATION

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    We estimate a random utility model of recreation demand accounting for choice set familiarity and favorite sites. Our approach differs from existing approaches by retaining all sites in estimating the parameters of site utility. Familiar and unfamiliar sites are specified with different utility functions. Favored sites are assumed to have higher utility than nonfavored sites in estimation.Resource /Energy Economics and Policy,

    The anthocyanin content in berries of the hybrid grape cultivars Clinton and Isabella

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    Berries of the hybrid grape cultivars Clinton and Isabella were analysed for their anthocyanin content and their anthocyanin profile. Antho-cyanins were extracted from grape skins by an ethanol/water/hydro-chloric acid solution. The extracts were used for spectrophotometric measurements and were purified by solid phase extraction to perform high performance liquid chromatography analysis (HPLC). As characteristics of hybrid grapes the anthocyanins 3,5-O-diglucoside and 3-O-(6-O-p-coumaroyl),5-O-diglucoside were identified. Many different anthocyanin compounds were found in Clinton grapes

    Proton electron elastic scattering and the proton charge radius

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    It is suggested that proton elastic scattering on atomic electrons allows a precise measurement of the proton charge radius. Very small values of transferred momenta (up to four order of magnitude smaller than the ones presently available) can be reached with high probability.Comment: 4 pages, 4 figure

    Observation of coherent π0\pi^0 electroproduction on deuterons at large momentum transfer

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    The first experimental results for coherent π0\pi^0-electroproduction on the deuteron, e+de+d+π0e+d\to e+d +\pi^0, at large momentum transfer, are reported. The experiment was performed at Jefferson Laboratory at an incident electron energy of 4.05 GeV. A large pion production yield has been observed in a kinematical region for 1.1<Q2<<Q^2<1.8 GeV2^2, from threshold to 200 MeV excitation energy in the dπ0d\pi^0 system. The Q2Q^2-dependence is compared with theoretical predictions.Comment: 26 page

    Fast and Accurate Algorithm for Eye Localization for Gaze Tracking in Low Resolution Images

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    Iris centre localization in low-resolution visible images is a challenging problem in computer vision community due to noise, shadows, occlusions, pose variations, eye blinks, etc. This paper proposes an efficient method for determining iris centre in low-resolution images in the visible spectrum. Even low-cost consumer-grade webcams can be used for gaze tracking without any additional hardware. A two-stage algorithm is proposed for iris centre localization. The proposed method uses geometrical characteristics of the eye. In the first stage, a fast convolution based approach is used for obtaining the coarse location of iris centre (IC). The IC location is further refined in the second stage using boundary tracing and ellipse fitting. The algorithm has been evaluated in public databases like BioID, Gi4E and is found to outperform the state of the art methods.Comment: 12 pages, 10 figures, IET Computer Vision, 201

    Influence of Blackberry Plants on the Aroma Profile of Vitis vinifera L. cv. Pinot Noir

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    V. vinifera cv. Pinot noir vines were grown in pots together with blackberry plants and the effect of this association on the grape aroma was assessed. Preliminary data showed that vines that cohabited with blackberry had a different aroma profile compared to vine grown alone. The association with blackberry increased the concentration of 30 out 74 free aroma compounds and of 24 out 95 bound ones. No aroma compound was identified exclusively in the treated grapes

    Decreased dopamine activity predicts relapse in methamphetamine abusers.

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    Studies in methamphetamine (METH) abusers showed that the decreases in brain dopamine (DA) function might recover with protracted detoxification. However, the extent to which striatal DA function in METH predicts recovery has not been evaluated. Here we assessed whether striatal DA activity in METH abusers is associated with clinical outcomes. Brain DA D2 receptor (D2R) availability was measured with positron emission tomography and [(11)C]raclopride in 16 METH abusers, both after placebo and after challenge with 60 mg oral methylphenidate (MPH) (to measure DA release) to assess whether it predicted clinical outcomes. For this purpose, METH abusers were tested within 6 months of last METH use and then followed up for 9 months of abstinence. In parallel, 15 healthy controls were tested. METH abusers had lower D2R availability in caudate than in controls. Both METH abusers and controls showed decreased striatal D2R availability after MPH and these decreases were smaller in METH than in controls in left putamen. The six METH abusers who relapsed during the follow-up period had lower D2R availability in dorsal striatum than in controls, and had no D2R changes after MPH challenge. The 10 METH abusers who completed detoxification did not differ from controls neither in striatal D2R availability nor in MPH-induced striatal DA changes. These results provide preliminary evidence that low striatal DA function in METH abusers is associated with a greater likelihood of relapse during treatment. Detection of the extent of DA dysfunction may be helpful in predicting therapeutic outcomes

    Winter pruning: Effect on root density, root distribution and root/canopy ratio in vitis vinifera cv. Pinot Gris

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    As in any other plant, the grapevine roots play a vital role in terms of anchorage, uptake of water and nutrients, as well as storage and production of chemicals. Their behaviour and development depend on various factors, namely rootstock genetics, soil physical and chemical features, and field agronomic practices. Canopy management, involving techniques such as defoliation and pruning, could greatly influence root growth. To date, most of the studies on grapevine winter pruning have focused on the effects on yield and quality of the grapes achievable through different pruning systems and techniques, while knowledge regarding root distribution, development, and growth in relation to winter pruning is still not completely understood. In this context, the purpose of our study was to investigate the effect of winter pruning on the root system of field-grown Vitis vinifera cv. Pinot Gris grafted onto rootstock SO4. We compared two pruning treatments (pruned-P and no pruned-NP) and analysed the effect on root distribution and density, the root index, and the root sugar reserve. Root data were analysed in relation to canopy growth and yield, to elucidate the effect of winter pruning on the root/yield ratio. Our data indicated that: (1) winter pruning stimulated the root growth and distribution; (2) canopy development was not negatively affected by this technique; (3) no pruned treatment produced less growth of the roots but a larger canopy. Information regarding both root growth and root canopy ratio is important as it gives us an understanding of the relationship between the aerial and subterranean parts of the plant, how they compete, and finally, offers us the possibility to ponder on the cultural practices
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