743 research outputs found

    THE EFFECT OF FEEDGRAIN PROGRAM PARTICIPATION ON CHEMICAL USE

    Get PDF
    Economic incentives created by the commodity programs are hypothesized to cause program participants to apply agrichemicals at greater rates than nonparticipants. Corn producers who participate in the USDA feedgrain program are shown to apply nitrogen, herbicides, and insecticides at statistically greater rates than those who do not participate.Crop Production/Industries,

    AGRICULTURE IN AN ECOSYSTEMS FRAMEWORK

    Get PDF
    By broadening the definition of an ecosystem to include economic activities, can we better characterize the interactions and relationships among agricultural activities and important indicators of ecological system health? This paper addresses research approaches for assessing the role of agriculture in an ecosystems context. Environmental regulation and resource management policies have heightened the interest in understanding interactions among agricultural activities and the natural resource base, including the impacts of agriculture on environmental quality and the impacts on agriculture of ecosystem restoration efforts. What are the most meaningful indicators of environmental quality? Which agricultural practices and policies should be considered, along with which nonagricultural resource uses? Finally, does the evolving thinking about ecosystems permit us to link agricultural practices and policies more directly and meaningfully to conceptions of sustainability, of both natural and socioeconomic systems? This paper presents a brief synopsis of ecosystem management, drawing from several recent governmental initiatives. It then provides an overview of the economics of ecosystem management from the perspective of the role of agriculture; discusses two specific cases, the Pacific Northwest and South Florida; and concludes with a discussion of promising economic approaches, data needs, and caveats to those engaged in policy analysis involving ecosystem restoration.Environmental Economics and Policy,

    15 Years: 15 Points of Progress, Transformational Leadership, 1997-2010 [Western Kentucky University]

    Get PDF
    This report, 15 Years: 15 Points of Progress, documents the most significant changes at WKU since our transformation began in late Fall, 1997. Our success is measurable. Our achievements are significant. Most importantly, our transformation is a lasting one

    Compactness for Holomorphic Supercurves

    Full text link
    We study the compactness problem for moduli spaces of holomorphic supercurves which, being motivated by supergeometry, are perturbed such as to allow for transversality. We give an explicit construction of limiting objects for sequences of holomorphic supercurves and prove that, in important cases, every such sequence has a convergent subsequence provided that a suitable extension of the classical energy is uniformly bounded. This is a version of Gromov compactness. Finally, we introduce a topology on the moduli spaces enlarged by the limiting objects which makes these spaces compact and metrisable.Comment: 38 page

    An exact sequence for contact- and symplectic homology

    Full text link
    A symplectic manifold WW with contact type boundary M=WM = \partial W induces a linearization of the contact homology of MM with corresponding linearized contact homology HC(M)HC(M). We establish a Gysin-type exact sequence in which the symplectic homology SH(W)SH(W) of WW maps to HC(M)HC(M), which in turn maps to HC(M)HC(M), by a map of degree -2, which then maps to SH(W)SH(W). Furthermore, we give a description of the degree -2 map in terms of rational holomorphic curves with constrained asymptotic markers, in the symplectization of MM.Comment: Final version. Changes for v2: Proof of main theorem supplemented with detailed discussion of continuation maps. Description of degree -2 map rewritten with emphasis on asymptotic markers. Sec. 5.2 rewritten with emphasis on 0-dim. moduli spaces. Transversality discussion reorganized for clarity (now Remark 9). Various other minor modification

    General Spectral Flow Formula for Fixed Maximal Domain

    Full text link
    We consider a continuous curve of linear elliptic formally self-adjoint differential operators of first order with smooth coefficients over a compact Riemannian manifold with boundary together with a continuous curve of global elliptic boundary value problems. We express the spectral flow of the resulting continuous family of (unbounded) self-adjoint Fredholm operators in terms of the Maslov index of two related curves of Lagrangian spaces. One curve is given by the varying domains, the other by the Cauchy data spaces. We provide rigorous definitions of the underlying concepts of spectral theory and symplectic analysis and give a full (and surprisingly short) proof of our General Spectral Flow Formula for the case of fixed maximal domain. As a side result, we establish local stability of weak inner unique continuation property (UCP) and explain its role for parameter dependent spectral theory.Comment: 22 page

    A comparison of collision cross section values obtained via travelling wave ion mobility-mass spectrometry and ultra high performance liquid chromatography-ion mobility-mass spectrometry : application to the characterisation of metabolites in rat urine

    Get PDF
    A comprehensive Collision Cross Section (CCS) library was obtained via Travelling Wave Ion Guide mobility measurements through direct infusion (DI). The library consists of CCS and Mass Spectral (MS) data in negative and positive ElectroSpray Ionisation (ESI) mode for 463 and 479 endogenous metabolites, respectively. For both ionisation modes combined, TWCCSN2 data were obtained for 542 non-redundant metabolites. These data were acquired on two different ion mobility enabled orthogonal acceleration QToF MS systems in two different laboratories, with the majority of the resulting TWCCSN2 values (from detected compounds) found to be within 1% of one another. Validation of these results against two independent, external TWCCSN2 data sources and predicted TWCCSN2 values indicated to be within 1-2% of these other values. The same metabolites were then analysed using a rapid reversed-phase ultra (high) performance liquid chromatographic (U(H)PLC) separation combined with IM and MS (IM-MS) thus providing retention time (tr), m/z and TWCCSN2 values (with the latter compared with the DI-IM-MS data). Analytes for which TWCCSN2 values were obtained by U(H)PLC-IM-MS showed good agreement with the results obtained from DI-IM-MS. The repeatability of the TWCCSN2 values obtained for these metabolites on the different ion mobility QToF systems, using either DI or LC, encouraged the further evaluation of the U(H)PLC-IM-MS approach via the analysis of samples of rat urine, from control and methotrexate-treated animals, in order to assess the potential of the approach for metabolite identification and profiling in metabolic phenotyping studies. Based on the database derived from the standards 63 metabolites were identified in rat urine, using positive ESI, based on the combination of tr, TWCCSN2 and MS data.</p
    corecore