3,283 research outputs found

    ECONOMICS OF MANAGING INVASIVE PEST SPECIES: EXCLUSION AND CONTROL

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    An important policy decision in managing invasive species is how to allocate resources between activities aimed at preventing the arrival of new pests - including additional arrivals of existing pests - and activities aimed at reducing the damages done by species that are already here. We develop a dynamic model for managing a generic invasive pest with an uncertain arrival date. The optimal conditions reveal that it is generally more efficient to spend a larger share of outlays for exclusion activities before a species arrives than after it is known to be here. They also show that outlays should be allocated such that the marginal costs of control measures equal the benefits from the marginal reduction of the species' population growth rate, and the marginal costs of exclusion measures equal the benefits from the marginal reduction of the rate of subsequent arrivals.Environmental Economics and Policy,

    ECONOMIC AND ENVIRONMENTAL BENEFITS OF SOIL/WATER NITROGEN TESTING: THE CASE OF CENTRAL NEBRASKA

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    This research presents a competitive dynamic model to evaluate the economic and groundwater quality benefits resulting from the adoption of soil/water nitrogen testing. The model is applied to an irrigated corn production county in the Nebraska Mid-State area where the groundwater contamination level from nitrates is reported to be, on average, 18.7 parts per million (ppm). Adoption of nutrient management practices would result in increased economic benefits to farmers and reduced nitrate stocks in groundwater.Environmental Economics and Policy,

    Induced-Innovation and Invasive Species Management

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    Public policy for managing invasive species has largely focused on preventive measures prior to detection (stage 1) and on the use of chemical/mechanical or biological control measures after the establishment and dispersion of the invasive species (stage 2). Optimal management policy depends both on the initial stock of the invasive species and on the costs associated with conventional control measures. However, little attention has focused on how an induced technology such as Bt corn and Bt cotton is developed and adopted by farmers (stage 3), or how it affects the manageability of economic and ecological damages from an invasive species. This analysis evaluates the optimal allocation of management resources between preventive and control measures for invasive species by incorporating induced technology under uncertainty into a conventional dynamic model of invasive species management.Invasive species, preventive measures, control measures, induced technology, hazard function, optimal control, comparative dynamic analysis, Environmental Economics and Policy, Production Economics,

    Structural Conservation Practices in U.S. Corn Production: Evidence on Environmental Stewardship by Program Participants and Non-Participants

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    This study used the 2005 ERS CEAP-ARMS data for corn production to first compare key operator, field, farm, economic, and environmental characteristics of conservation program participants with non-participants, by farm-size class. We then estimate a cost-function based technology adoption model of producer decisions regarding the allocation of field-level acres between corn production and infield and perimeter-field conservation structures to examine how these conservation choices differ between program participants and non-participants, while accounting for differences in other field, farm, and environmental factors. Our null hypothesis is that the average conservation structural practice acres across U.S. corn acres supplied by growers participating in a conservation program are not different from non-participants. Infield conservation structures include terraces, grassed waterways, vegetative buffers, contour buffers, filter strips, and grade stabilization structures. Perimeter-field conservation structures include hedgerow plantings, stream-side forest and herbaceous buffers, windbreaks and herbaceous wind barriers, field borders, and critical area plantings. Because the dependent variable in this analysis is continuous, we use a Generalized Estimating Equations (GEE) procedure to estimate two models. The GEE estimation procedure (Liang and Zeger, 1986) accounts for correlation between adoption decisions measured as a continuous variable while maintaining the theoretical integrity of a multinomial discrete-choice model typically used in technology adoption studies. The cost-function models estimate field-level, producer acreage allocation decisions for corn, first, as a function of normalized production input costs (prices) and structural technology class and installation time-period attributes (Model 1), and second, as a function of Model 1 variables plus socio-environmental variables reflecting the potential influence of a variety of field, farm, and environmental characteristics (Model 2). Evidence indicates significant characteristic differences exist between conservation program participants and non-participants across U.S. corn production, that non-program factors do heavily influence producer conservation practice decisions, and that farm-size matters. In addition, results suggest that program non-participants tend to adopt infield conservation structures much more intensively while program participants emphasize the adoption of perimeter-field conservation structures. Finally, these results seem to suggest that because perimeter-field structural practices can involve differential productivity/cost effects and off-site benefits, program incentives may need to play a greater role in encouraging their adoption than they do for infield structural practices.Crop Production/Industries, Environmental Economics and Policy,

    Towards a Sustainable Future: The Dynamic Adjustment Path of Irrigation Technology and Water Management in Western U.S. Agriculture

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    Technology adoption, Water conservation, Irrigation, Dynamic groundwater models, Sustainable agriculture, Environmental Economics and Policy, Resource /Energy Economics and Policy,

    Measurement of Vub|V_{ub}| in semi-inclusive charmless BπXB \to \pi X decays

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    We study semi-inclusive charmless decays BπXB \to \pi X, where XX does not contain a charm (anti)quark. The mode Bˉ0πX\bar B^0 \to \pi^- X turns out to be be particularly useful for determination of the CKM matrix element Vub|V_{ub}|. We present the branching ratio (BR) of Bˉ0πX\bar B^0 \to \pi^- X as a function of Vub|V_{ub}|, with an estimation of possible uncertainty. The BR is expected to be an order of 10410^{-4}.Comment: 3 pages, 2 figures, Proceedings of the Fifth KEK Topical Conferenc

    Permanence of Carbon Sequestered in Forests under Uncertainty

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    In this paper we examine the issue of permanence in the context of sequestering carbon through afforestation. We develop a dynamic nested optimal control model of carbon sequestration associated with the decision to afforest a tract of land given there are uncertainties associated with fire and insect/disease hazards. Conceptually, these potential hazards are similar in that their occurrence at any time t is uncertain and landowners can take specific actions – although generally different actions - in any time period t to reduce the probability of sustaining losses related to them. The hazards differ, however, in that fire represents a large loss in carbon at a moment in time, while insect/disease infestations are more likely to be reflected in a period of significant slowing of the rate of carbon accumulation than was anticipated followed by a sustained period of slowly decreasing carbon losses. The nature of these losses will influence the design of incentives under GHG mitigation frameworks that require carbon losses to be replaced as well as the strategies farmers adopt to deal with the uncertainties associated with these events occurring.carbon sequestration, uncertainty, optimal control, hazard function, forestry, permanence, Environmental Economics and Policy, Land Economics/Use,

    Prevention or Control: Optimal Government Policies for Invasive Species Management

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    We present a conceptual, but empirically applicable, model for determining the optimal allocation of resources between exclusion and control activities for managing an invasive species with an uncertain discovery time. This model is used to investigate how to allocate limited resources between activities before and after the first discovery of an invasive species and the effects of the characteristics of an invasive species on limited resource allocation. The optimality conditions show that it is economically efficient to spend a larger share of outlays for exclusion activities before, rather than after, a species is first discovered, up to a threshold point. We also find that, after discovery, more exclusionary measures and fewer control measures are optimal, when the pest population is less than a threshold. As the pest population increases beyond this threshold, the exclusionary measures are no longer optimal. Finally, a comparative dynamic analysis indicates that the efficient level of total expenditures on preventive and control measures decreases with the level of the invasive species stock and increases with the intrinsic population growth rate, the rate of additional discoveries avoided, and the maximum possible pest population.invasive species, exclusion, control, eradication, public expenditures, Environmental Economics and Policy, Resource /Energy Economics and Policy,

    Large pTp_T Hadroproduction of ZZ as a Probe of Gluon Distribution inside Proton

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    The transverse momentum distribution of single vector boson production at hadron colliders provides useful ways of testing the Standard Model and searching new physics beyond the Standard Model. We study large pTp_{_T} hadroproduction of ZZ-boson as a probe of gluon distributions inside proton. We investigate how to get initial gluon-involving contributions, or how to subtract quark-quark (or -antiquark) contributions from total cross section. We also investigated the simultaneous measurement of the rapidity and the transverse momentum of the produced ZZ boson, to obtain momentum fractions of initial partons. And we extracted relevant uncertainties involving in experimental and theoretical analyses. This large pTp_{_T} hadroproduction of ZZ can be used as constraints on analyses of global parton (gluon and quarks) distribution functions inside proton.Comment: (a) 13 pages(LaTeX) + 1 figure ps file(3 pages):compressed, uuencoded (b) accepted by Phys.Lett.B. (c) some figures are combined and one is omitted. (d) conclusion part is included into abstrac

    Measurement of the Width Difference of B_d Mesons

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    We estimate \Delta Gamma_d/\Gamma_d, including 1/m_b contributions and part of the next-to-leading order QCD corrections, and find it to be around 0.3%. We show the methods to measure \Delta Gamma_d/\Gamma_d by using at least two different final states on the untagged B_d decay. The nonzero width difference can also be used to identify new physics effects and to resolve a twofold discrete ambiguity in the B_d-\bar{B}_d mixing phase. With the high statistics and accurate time resolution of the upcoming LHC experiment, the measurement of \Delta Gamma_d seems to be possible. This measurement would be important for an accurate measurement of \sin2\phi_1 at the LHC. We also derive an upper bound on the value of \Delta Gamma_d/\Gamma_d in the presence of new physics.Comment: 3 pages, LaTeX, Presented at the 5th KEK Topical Conference(KEKTC5
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