10,545 research outputs found

    Evaluation of the nutrient status of wheat plants

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    The balance of the principal ionic constituents in plants is reviewed in relation to the requirements for each of the elements, and for total accumulation as reflected in the total cation content (C), the inorganic anion conent (A) and the organic anion content (C-A). The balance in young wheat plants is investigated by means of adding various combinations of the principal ions to the soil. A summary of tests on adequacy of supply with the principal nutrient ions and of accumulation of cations, inorganic anions and organic anions, based on critical values. for contents in the plant material, is presented for diagnosing the nutrient status in relation to capacity for maximum growth

    Temporal changes in carboxylate content of ryegrass with stepwise change in nutrition

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    A detailed scheme of carboxylate formation and retention by plant tissues as a result of ion uptake and utilization is given. By means of discontinuities in the supply with nutrient ions, carboxylate retention by the tissues of perennial ryegrass was followed as a function of growth. It was found that translocation of potassium nitrate to the shoot and subsequent nitrate metabolism was the only process capable of supplying the shoot with sufficient carboxylates and of removing the excess from the foliage to the root system with maintenance of the normal carboxylate content. Absorbed bicarbonate was a good source of carboxylates in the roots, but the rate of translocation to the plant tops was too slow relative to growth. Therefore, the carboxylate concentration in the foliage fell progressively to one half the normal value. Constancy of carboxylate concentration in the dry matter was related to the early establishment of the proportion of carboxylates to dry material in the new growth, making it independent of subsequent changes in water content of the tissues. Changes in carboxylate concentrations due to changes in the supply were continuous with time. Nitrate caused a depression in the roots during nitrate accumulation, but the nitrate metabolism in the follage made sufficient carboxylates available for replenishment and maintenance of their normal level in the whole plant

    Deception Island Volcanism (South Shetland Islands, Antarctica): Results from Thin-Section Invertigations

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    Are Nonclinical Obsessive-Compulsive Symptoms Associated with Bias Toward Habits?

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    In a sample of student volunteers (N=93), we found that obsessive-compulsive symptoms (although not hoarding) were associated with overreliance on stimulus-response habits at the expense of goal-directed control during instrumental responding. Only checking symptoms were associated with bias toward habits after negative affect was controlled for. Further research is warranted to examine if overreliance on habits represents an aberrant learning process that confers risk for obsessive-compulsive psychopathology

    Trends in multiparticle production and some "predictions" for pp and PbPb collisions at LHC

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    Based on trends seen at lower energies we "predict" the multiplicities and pseudorapidity distributions of particle density and elliptic flow that will be seen in PbPb and pp collisions at the LHC. We argue that, if these predictions turn out to be correct, either these quantities are insensitive to the state of matter created in high energy heavy ion collisions or the observed simplicity and universality of the data must be telling us something profound about the mechanism of particle production, which to this date is not well understood.Comment: Invited Talk at SQM2007 Conferenc

    The EU Customs Union after Brexit

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    In this contribution the author examines how, from a customs perspective, the integrity of the internal market is protected after the transitional phase under the Revised Protocol on Ireland/Northern Ireland. He briefly discusses the customs aspects of the Withdrawal Agreement and then examines in depth the revised arrangement with regard to the Irish border in light of the protection of the integrity of the internal market. He shows that the revised arrangement cleared the Brexit d
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