1,247 research outputs found

    Wheat productivity estimates using LANDSAT data

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    The author has identified the following significant results. Large area LANDSAT yield estimates were generated. These results were compared with estimates computed using a meteorological yield model (CCEA). Both of these estimates were compared with Kansas Crop and Livestock Reporting Service (KCLRS) estimates of yield, in an attempt to assess the relative and absolute accuracy of the LANDSAT and CCEA estimates. Results were inconclusive. A large area direct wheat prediction procedure was implemented. Initial results have produced a wheat production estimate comparable with the KCLRS estimate

    Chain-store pricing and the structure of retail markets

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    This paper examines competition between chain-stores and independent retailers in the UK retail opticians' market. We demonstrate that the pricing policy adopted by chain-stores can determine the impact their entry has on independent retailers. Crucially, in this market the chain-store retailers set an identical national price across all local markets. Our results suggest that this pricing strategy lessens the detrimental effect competition from chain-stores has on independent retailers

    Cluster Performance reconsidered: Structure, Linkages and Paths in the German Biotechnology Industry, 1996-2003

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    This paper addresses the evolution of biotechnology clusters in Germany between 1996 and 2003, paying particular attention to their respective composition in terms of venture capital, basic science institutions and biotechnology firms. Drawing upon the significance of co-location of "money and ideas", the literature stressing the importance of a cluster's openness and external linkages, and the path dependency debate, the paper aims to analyse how certain cluster characteristics correspond with its overall performance. After identifying different cluster types, we investigate their internal and external interconnectivity in comparative manner and draw on changes in cluster composition. Our results indicate that the structure, i.e. to which group the cluster belongs, and the openness towards external knowledge flows deliver merely unsystematic indications with regard to a cluster's overall success. Its ability to change composition towards a more balanced ratio of science and capital over time, on the other hand, turns out as a key explanatory factor. Hence, the dynamic perspective proves effective illuminating cluster growth and performance, where our explorative findings provide a promising avenue for further evolutionary research

    The JCMT Gould Belt Survey: A First Look at the Auriga–California Molecular Cloud with SCUBA-2

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    We present 850 and 450 μm observations of the dense regions within the Auriga–California molecular cloud using SCUBA-2 as part of the JCMT Gould Belt Legacy Survey to identify candidate protostellar objects, measure the masses of their circumstellar material (disk and envelope), and compare the star formation to that in the Orion A molecular cloud. We identify 59 candidate protostars based on the presence of compact submillimeter emission, complementing these observations with existing Herschel/SPIRE maps. Of our candidate protostars, 24 are associated with young stellar objects (YSOs) in the Spitzer and Herschel/PACS catalogs of 166 and 60 YSOs, respectively (177 unique), confirming their protostellar nature. The remaining 35 candidate protostars are in regions, particularly around LkHα 101, where the background cloud emission is too bright to verify or rule out the presence of the compact 70 μm emission that is expected for a protostellar source. We keep these candidate protostars in our sample but note that they may indeed be prestellar in nature. Our observations are sensitive to the high end of the mass distribution in Auriga–Cal. We find that the disparity between the richness of infrared star-forming objects in Orion A and the sparsity in Auriga–Cal extends to the submillimeter, suggesting that the relative star formation rates have not varied over the Class II lifetime and that Auriga–Cal will maintain a lower star formation efficiency

    Machine Intelligence Identifies Soluble TNFa as a Therapeutic Target for Spinal Cord Injury

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    Traumatic spinal cord injury (SCI) produces a complex syndrome that is expressed across multiple endpoints ranging from molecular and cellular changes to functional behavioral deficits. Effective therapeutic strategies for CNS injury are therefore likely to manifest multi-factorial effects across a broad range of biological and functional outcome measures. Thus, multivariate analytic approaches are needed to capture the linkage between biological and neurobehavioral outcomes. Injury-induced neuroinflammation (NI) presents a particularly challenging therapeutic target, since NI is involved in both degeneration and repair. Here, we used big-data integration and large-scale analytics to examine a large dataset of preclinical efficacy tests combining five different blinded, fully counter-balanced treatment trials for different acute anti-inflammatory treatments for cervical spinal cord injury in rats. Multi-dimensional discovery, using topological data analysis (TDA) and principal components analysis (PCA) revealed that only one showed consistent multidimensional syndromic benefit: intrathecal application of recombinant soluble TNFα receptor 1 (sTNFR1), which showed an inverse-U dose response efficacy. Using the optimal acute dose, we showed that clinically-relevant 90 min delayed treatment profoundly affected multiple biological indices of NI in the first 48 h after injury, including reduction in pro-inflammatory cytokines and gene expression of a coherent complex of acute inflammatory mediators and receptors. Further, a 90 min delayed bolus dose of sTNFR1 reduced the expression of NI markers in the chronic perilesional spinal cord, and consistently improved neurological function over 6 weeks post SCI. These results provide validation of a novel strategy for precision preclinical drug discovery that is likely to improve translation in the difficult landscape of CNS trauma, and confirm the importance of TNFα signaling as a therapeutic target

    Entry, Exit, and the Determinants of Market Structure

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    This paper estimates a dynamic, structural model of entry and exit in an oligopolistic industry and uses it to quantify the determinants of market structure and long-run firm values for two U.S. service industries, dentists and chiropractors. Entry costs faced by potential entrants, fixed costs faced by incumbent producers, and the toughness of short-run price competition are all found to be important determinants of long-run firm values, firm turnover, and market structure. Estimates for the dentist industry allow the entry cost to differ for geographic markets that were designated as Health Professional Shortage Areas and in which entry was subsidized. The estimated mean entry cost is 11 percent lower in these markets. Using simulations, we compare entry-cost versus fixed-cost subsidies and find that entry-cost subsidies are less expensive per additional firm

    An integrative framework of preemption strategies

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    Pre-print; author's draftThis paper performs a review of the various pre-emption strategies prescribed in the economics literature. These are cost superiority, consumers' switching cost, channel exclusivity, environmental barriers of entry and credible commitment to react aggressively. Through our analysis, we develop an integrative framework of the pre-emption strategies that will result in long-term payoffs to the firm. The framework proposes that there are two key dimensions—strategic advantage and strategic focus—and identify five generic types of pre-emption strategies for market incumbents. These are the switching cost, blockade, credible commitment, tie-up, and cost leadership strategies. The pre-emption strategies and the framework presented can assist managerial decision-making for the successful pre-emption of potential competition to complement their existing efforts

    Bottleneck co-ownership as a regulatory alternative

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    This paper proposes a regulatory mechanism for vertically related industries in which the upstream “bottleneck” segment faces significant returns to scale while other (downstream) segments may be more competitive. In the proposed mechanism, the ownership of the upstream firm is allocated to downstream firms in proportion to their shares of input purchases. This mechanism, while preserving downstream competition, partially internalizes the benefits of exploiting economies of scale resulting from an increase in downstream output. We show that this mechanism is more efficient than a disintegrated market structure in which the upstream natural monopoly bottleneck sets a price equal to average cost

    A census of dense cores in the Taurus L1495 cloud from the Herschel Gould Belt Survey

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    We present a catalogue of dense cores in a ∼4° × 2° field of the Taurus star-forming region, inclusive of the L1495 cloud, derived from HerschelSPIRE and PACS observations in the 70 μm, 160 μm, 250 μm, 350 μm, and 500 μm continuum bands. Estimates of mean dust temperature and total mass are derived using modified blackbody fits to the spectral energy distributions. We detect 528 starless cores of which ∼10–20% are gravitationally bound and therefore presumably prestellar. Our census of unbound objects is ∼85% complete for M > 0.015 M⊙ in low density regions (AV∼M > 0.1 M⊙ overall. The prestellar CMF is consistent with lognormal form, resembling the stellar system initial mass function, as has been reported previously. All of the inferred prestellar cores lie on filamentary structures whose column densities exceed the expected threshold for filamentary collapse, in agreement with previous reports. Unlike the prestellar CMF, the unbound starless CMF is not lognormal, but instead is consistent with a power-law form below 0.3 M⊙ and shows no evidence for a low-mass turnover. It resembles previously reported mass distributions for CO clumps at low masses (M∼<0.3M⊙M∼<0.3M⊙). The volume density PDF, however, is accurately lognormal except at high densities. It is consistent with the effects of self-gravity on magnetized supersonic turbulence. The only significant deviation from lognormality is a high-density tail which can be attributed unambiguously to prestellar cores
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