6,797 research outputs found

    Advanced content-based semantic scene analysis and information retrieval: the SCHEMA project

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    The aim of the SCHEMA Network of Excellence is to bring together a critical mass of universities, research centers, industrial partners and end users, in order to design a reference system for content-based semantic scene analysis, interpretation and understanding. Relevant research areas include: content-based multimedia analysis and automatic annotation of semantic multimedia content, combined textual and multimedia information retrieval, semantic -web, MPEG-7 and MPEG-21 standards, user interfaces and human factors. In this paper, recent advances in content-based analysis, indexing and retrieval of digital media within the SCHEMA Network are presented. These advances will be integrated in the SCHEMA module-based, expandable reference system

    Stress relaxation and mechanical properties of RL-1973 and PD-200-16 silicone resin sponge materials

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    Stress relaxation tests were conducted by loading specimens in double-lap shear to a preselected strain level and monitoring the decay of stress with time. The stress relaxation response characteristics were measured over a temperature range of 100 to 300 K and four strain levels. It is concluded that only a slight amount of stress relaxation was observed, and the stiffness increased approximately two orders of magnitude over the range of temperatures

    \u3cem\u3eRhizobium japonicum\u3c/em\u3e Mutants Defective in Symbiotic Nitrogen Fixation

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    Rhizobium japonicum strains 3I1b110 and 61A76 were mutagenized to obtain 25 independently derived mutants that produced soybean nodules defective in nitrogen fixation, as assayed by acetylene reduction. The proteins of both the bacterial and the plant portions of the nodules were analyzed by two-dimensional polyacrylamide gel electrophoresis. All of the mutants had lower-than-normal levels of the nitrogenase components, and all but four contained a prominent bacteroid protein not observed in wild-type bacteroids. Experiments with bacteria grown ex planta suggested that this protein was derepressed by the absence of ammonia. Nitrogenase component II of one mutant was altered in isoelectric point. The soluble plant fraction of the nodules of seven mutants had very low levels of heme, yet the nodules of five of these seven mutants contained the polypeptide of leghemoglobin. Thus, the synthesis of the globin may not be coupled to the content of available heme in soybean nodules. The nodules of the other two of these seven mutants lacked not only leghemoglobin but most of the other normal plant and bacteroid proteins. Ultrastructural examination of nodules formed by these two mutants indicated normal ramification of infection threads but suggested a problem in subsequent survival of the bacteria and their release from the infection threads

    Does the Sun shrink with increasing magnetic activity?

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    It has been demonstrated that frequencies of f-modes can be used to estimate the solar radius to a good accuracy. These frequencies have been used to study temporal variations in the solar radius with conflicting results. The variation in f-mode frequencies is more complicated than what is assumed in these studies. If a careful analysis is performed then it turns out that there is no evidence for any variation in the solar radius.Comment: To appear in Astrophys.

    Empirical model for quasi direct current interruption with a convoluted arc

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    This contribution considers various aspects of a quasi direct current, convoluted arc produced by a magnetic field (B-field) connected in parallel with an RLC circuit that have not been considered in combination. These aspects are the arc current limitation due to the arc convolution, changes in arc resistance due to the B-field and material ablation, and the relative significance of the RLC circuit in producing an artificial current zero. As a result, it has been possible to produce an empirical equation for predicting the current interruption capability in terms of the B-field magnitude and RLC components

    An Economic Assessment of the 1999 Drought: Agricultural Impacts Are Severe Locally, but Limited Nationally

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    While the 1999 drought has had severe financial impacts on agricultural producers in the drought regions, its impact on U.S. agricultural production has been limited. The drought will reduce commodity receipts relative to 1998 by an estimated 1.29billion.Estimatedfarmnetincomelosses,includingexpectedyieldlosses,increasesinexpenses,andinsuranceindemnities,willtotal1.29 billion. Estimated farm net income losses, including expected yield losses, increases in expenses, and insurance indemnities, will total 1.35 billion, about 3 percent of expected 1999 U.S. net farm income. Drought impacts in areas of the Northeast designated as extreme and severe drought are expected to reduce farmers' net income by nearly $840 million. The regions affected, the crops grown in those regions, the increased use of irrigation, and crop insurance coverage limited the drought's impacts on agriculture nationally. Drought also affects the rural population by reducing water supplies available for human and livestock consumption.Agricultural Finance, Farm Management,

    Soil-landscape mapping in south-Western Australia : an overview of methodology and outputs

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    This report provides an overview of the soil-landscape mapping program for south-Western Australia. It outlines the techniques and standards used in describing the soil-landscape as well as the outputs of the mapping program and their uses

    POLICY DIRECTIONS TO MITIGATE WATER-SUPPLY RISK IN IRRIGATED AGRICULTURE: A FEDERAL PERSPECTIVE

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    Water reallocation to meet mandated flow requirements and trust responsibilities, established in Federal law and water authority, can result in large uncompensated losses to irrigated agriculture. This paper discusses the nature and potential cost of water-supply interruptions due to Federal actions, and provides a comparative assessment of alternative risk-mitigation measures.Resource /Energy Economics and Policy,
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