14,999 research outputs found

    Effects of Market Power on the Size and Distribution of Subsidy Benefits: The Case of Ethanol Promotion

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    The subject of market power is discussed frequently in debates about subsidies for ethanol production, and structural conditions in the industry create a prima-facie case for concerns about market power. This paper develops a prototype model for determining the production and price impacts and distribution of benefits from the U.S. ethanol subsidy when upstream sellers in the seed sector and downstream buyers in the processing sector may exercise market power. The impact of the subsidy is analyzed within a simulation framework for alternative levels of market power. Results demonstrate that the impacts on prices and output are limited for modest departures from competition. Distributional impacts are much greater. Seed producers and corn processors with market power are able to capture relatively large shares of the benefits from the subsidy. A perhaps surprising result is that upstream oligopoly power exercised by seed producers is prospectively as important in influencing the positive and distributional impacts of the subsidy as the much more frequently discussed and debated prospect that downstream corn processors may exercise buyer power.Resource /Energy Economics and Policy,

    Hidden innovation in the construction and property sectors

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    The construction and property industries have a poor reputation for innovation. Indeed, this reputation appears to be backed by official statistics which projects these industries as being devoid of innovative activity. However, the reputation is undeserved. Official statistics misrepresent the extent and nature of innovation in these sectors. A closer analysis reveals that much of the innovation that exists in the sector is hidden from conventional measures. By its nature therefore, it is difficult to measure the precise extent of this innovation and disaggregate it from general improvement. This opaqueness strengthens the need for policymakers, practitioners and researchers within, amongst others, the surveying sector to go beyond the visible spectrum of innovation and design and implement appropriate policies, knowledge bases and practices which engage and leverage the hitherto hidden aspects of innovation

    Amenities and the labor earnings function

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    I was unable to copy/paste the abstract, but the paper argues that amenities exert an important effect on wage differentials over space. Indeed, we show that as much has half of the apparent effect of unionization on wages is actually compensation for less desirable climate in locations that are most unionized.amenities; climate; weather; wage compensation; return to unionization

    Systems Integration Processes for NASA Ares I Crew Launch Vehicle

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    NASA's Exploration Initiative will require development of many new elements to constitute a robust system of systems. New launch vehicles are needed to place cargo and crew in stable Low Earth Orbit (LEO). This paper examines the systems integration processes NASA is utilizing to ensure integration and control of propulsion and nonpropulsion elements within NASA's Crew Launch Vehicle (CLV), now known as the Ares I. The objective of the Ares I is to provide the transportation capabilities to meet the Constellation Program requirements for delivering a Crew Exploration Vehicle (CEV) or other payload to LEO in support of the lunar and Mars missions. The Ares I must successfully provide this capability within cost and schedule, and with an acceptable risk approach. This paper will describe the systems engineering management processes that will be applied to assure Ares I Project success through complete and efficient technical integration. Discussion of technical review and management processes for requirements development and verification, integrated design and analysis, integrated simulation and testing, and the integration of reliability, maintainability and supportability (RMS) into the design will also be included. The Ares I Project is logically divided into elements by the major hardware groupings, and associated management, system engineering, and integration functions. The processes to be described herein are designed to integrate within these Ares I elements and among the other Constellation projects. Also discussed is launch vehicle stack integration (Ares I to CEV, and Ground and Flight Operations integration) throughout the life cycle, including integrated vehicle performance through orbital insertion, recovery of the first stage, and reentry of the upper stage. The processes for decomposing requirements to the elements and ensuring that requirements have been correctly validated, decomposed, and allocated, and that the verification requirements are properly defined to ensure that the system design meets requirements, will be discussed

    Development of the Brief Ageing Perceptions Questionnaire (B-APQ): a confirmatory factor analysis approach to item reduction.

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    BACKGROUND: This paper aimed to develop a short version of the 32-item Ageing Perceptions Questionnaire (APQ), a multi-dimensional measure based on Leventhal\u27s self-regulation model. Ageing perceptions are a key area of interest for large-scale surveys of ageing populations. As these studies capture a broad range of health and social variables, included instruments need to be as concise as possible. METHODS: Data from the Irish Longitudinal Study of Ageing (TILDA), a representative sample of community-dwelling individuals aged 50+ (n = 6,718), was used to revise the scale. Items for exclusion were identified by examining conceptual content, descriptive statistics, and by detecting sources of poor model fit using confirmatory factor analysis (CFA). Potential combinations of dimensions were also tested using CFA. Finally, we identified any dimensions that could be excluded without limiting the conceptual coverage and coherence of the scale. Model modifications were done sequentially and with regard to theoretical considerations. Internal consistency and construct validity of the concise scale were compared with the longer version. RESULTS: Initially, 11 items were excluded on the basis of conceptual and empirical overlap with other items. CFA indicated that the negative-control and negative-consequences dimensions could be combined, allowing us to exclude a further item from this dimension. The 5-item timeline-cyclical dimension was also excluded, as it was less well-established conceptually and empirically than the other dimensions. The final 17-item, 5-dimension model was consistent with the original conceptual model and fit the data well (chi-sq = 1433.54, df(109), p CONCLUSIONS: The Brief-APQ (B-APQ) is a concise, multi-dimensional measure of ageing perceptions, which is psychometrically valid for use with the Irish population aged 50+. The concise version preserved the internal consistency and construct validity of the original. Its brevity makes it particularly suitable for use with large-scale adult population surveys. The psychometric analysis supports the application of the self-regulation model to ageing perceptions, but also the existence of distinct \u22physical decline\u22 and \u22ongoing development\u22 dimensions of perceptions

    Hybrid meson decay from the lattice

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    We discuss the allowed decays of a hybrid meson in the heavy quark limit. We deduce that an important decay will be into a heavy quark non-hybrid state and a light quark meson, in other words, the de-excitation of an excited gluonic string by emission of a light quark-antiquark pair. We discuss the study of hadronic decays from the lattice in the heavy quark limit and apply this approach to explore the transitions from a spin-exotic hybrid to χbη\chi_b \eta and χbS\chi_b S where SS is a scalar meson. We obtain a signal for the transition emitting a scalar meson and we discuss the phenomenological implications.Comment: 18 pages, LATEX, 3 ps figure

    Modulation of mitochondrial activity in HaCaT keratinocytes by the cell penetrating peptide Z-Gly-RGD(DPhe)-mitoparan.

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    OBJECTIVE: Biologically active cell penetrating peptides (CPPs) are an emerging class of therapeutic agent. The wasp venom peptide mastoparan is an established CPP that modulates mitochondrial activity and triggers caspase-dependent apoptosis in cancer cells, as does the mastoparan analogue mitoparan (mitP). Mitochondrial depolarisation and activation of the caspase cascade also underpins the action of dithranol, a topical agent for treatment of psoriasis. The effects of a potent mitP analogue on mitochondrial activity were therefore examined to assess its potential as a novel approach for targeting mitochondria for the treatment of psoriasis. RESULTS: In HaCaT keratinocytes treated with the mitP analogue Z-Gly-RGD(DPhe)-mitP for 24 h, a dose-dependent loss of mitochondrial activity was observed using the methyl-thiazolyl-tetrazolium (MTT) assay. At 10 μmol L-1, MTT activity was less than 30% that observed in untreated cells. Staining with the cationic dye JC-1 suggested that Z-Gly-RGD(DPhe)-mitP also dissipated the mitochondrial membrane potential, with a threefold increase in mitochondrial depolarisation levels. However, caspase activity appeared to be reduced by 24 h exposure to Z-Gly-RGD(DPhe)-mitP treatment. Furthermore, Z-Gly-RGD(DPhe)-mitP treatment had little effect on overall cell viability. Our findings suggest Z-Gly-RGD(DPhe)-mitP promotes the loss of mitochondrial activity but does not appear to evoke apoptosis in HaCaT keratinocytes

    Hadron Mass Predictions of the Valence Approximation to Lattice QCD

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    We evaluate the infinite volume, continuum limits of eight hadron mass ratios predicted by lattice QCD with Wilson quarks in the valence (quenched) approximation. Each predicted ratio differs from the corresponding observed value by less than 6\%.Comment: 13 pages of Latex + 2 PostScript files attached, IBM/HET 92-
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