5,500 research outputs found

    Rubisco : easy purification and immunochemical determination

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    Rubisco (Ribulose-1.5-bisphosphate carboxylase/oxygenase) from spinach was purified to homogeneity in one step by gel filtration. This enzyme is suitable for the generation of a specific antibody in rabbits. The enzyme concentration in spinach leaves amounted to 40 % of the total soluble protein. The specific antibody shows cross reaction with crude extracts from leaves of other higher plants. The enzymes subunits could be separated by denaturing preparative SDS gel electrophoresis

    Intrafirm trade with ASEAN countries by Japanese and US multinational corporations

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    During the last decade, the role of multinational corporations in international trade has received a steadily increasing attention. In a wide sense, multinational corporations are reported to manage an increasing share of international trade thereby bridging the gap between production for local and foreign markets and intensifying the international division of labour. In a narrow sense, trade between parent companies and their overseas affiliates (so called intrafirm trade) has provoked attention because this trade may challenge - by its very nature - conventional understanding of determinants of international trade and the impact of trade policies. The evidence on intrafirm trade is scant at best, however, and is almost exclusively related to the US. Therefore this paper tries to update and improve the empirical basis on intrafirm trade by giving answers to the following questions: - Which role does intrafirm trade play in international trade of home-countries other than the US? - Is intrafirm trade of major home countries region-specific and/or industry-specific and if so what are the specific characteristics of regions and industries where intrafirm trade is relatively important? - How has intrafirm trade developed over time? - Does the structural pattern of intrafirm trade conform to that of the underlying activity, that is foreign direct investment?

    Finite order automorphisms and real forms of affine Kac-Moody algebras in the smooth and algebraic category

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    Automorphisms of finite order and real forms of "smooth" affine Kac-Moody algebras are studied, i.e. of 2-dimensional extensions of the algebra of smooth loops in a simple Lie algebra. It is shown that they can be parametrized by certain invariants and that in particular the classification of involutions essentially follows from Cartan's classifications in finite dimensions. We also prove that our approach works equally well in the usual algebraic setting and leads to the same results there

    Quantifying high-frequency market reactions to real-time news sentiment announcements

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    We examine intra-day market reactions to news in stock-specific sentiment disclosures. Using pre-processed data from an automated news analytics tool based on linguistic pattern recognition we extract information on the relevance as well as the direction of company-specific news. Information-implied reactions in returns, volatility as well as liquidity demand and supply are quantified by a high-frequency VAR model using 20 second intervals. Analyzing a cross-section of stocks traded at the London Stock Exchange (LSE), we find market-wide robust news-dependent responses in volatility and trading volume. However, this is only true if news items are classified as highly relevant. Liquidity supply reacts less distinctly due to a stronger influence of idiosyncratic noise. Furthermore, evidence for abnormal highfrequency returns after news in sentiments is shown. JEL-Classification: G14, C3

    General Bounds for Incremental Maximization

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    We propose a theoretical framework to capture incremental solutions to cardinality constrained maximization problems. The defining characteristic of our framework is that the cardinality/support of the solution is bounded by a value kNk\in\mathbb{N} that grows over time, and we allow the solution to be extended one element at a time. We investigate the best-possible competitive ratio of such an incremental solution, i.e., the worst ratio over all kk between the incremental solution after kk steps and an optimum solution of cardinality kk. We define a large class of problems that contains many important cardinality constrained maximization problems like maximum matching, knapsack, and packing/covering problems. We provide a general 2.6182.618-competitive incremental algorithm for this class of problems, and show that no algorithm can have competitive ratio below 2.182.18 in general. In the second part of the paper, we focus on the inherently incremental greedy algorithm that increases the objective value as much as possible in each step. This algorithm is known to be 1.581.58-competitive for submodular objective functions, but it has unbounded competitive ratio for the class of incremental problems mentioned above. We define a relaxed submodularity condition for the objective function, capturing problems like maximum (weighted) (bb-)matching and a variant of the maximum flow problem. We show that the greedy algorithm has competitive ratio (exactly) 2.3132.313 for the class of problems that satisfy this relaxed submodularity condition. Note that our upper bounds on the competitive ratios translate to approximation ratios for the underlying cardinality constrained problems.Comment: fixed typo
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