198 research outputs found

    Smallness of a commodity and partial equilibrium analysis

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    Partial equilibrium analysis has a conceptual dilemma that its object should be negligibly small in order to be free from income effect but then the consumer does not care for it and the notion of willingness to pay for it does not make sense. In the setting of a continuum of commodities, we propose a limiting procedure which transforms the general many-commodity framework into a partial single-commodity framework. In the limit, willingness to pay for a commodity is established as a density notion and it is shown to be free from income effect. This pins down an exact relationship between general equilibrium analysis and partial equilibrium analysis

    Involvement of S-adenosylmethionine-dependent halide/thiol methyltransferase (HTMT) in methyl halide emissions from agricultural plants: isolation and characterization of an HTMT-coding gene from Raphanus sativus (daikon radish)

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    <p>Abstract</p> <p>Background</p> <p>Biogenic emissions of methyl halides (CH<sub>3</sub>Cl, CH<sub>3</sub>Br and CH<sub>3</sub>I) are the major source of these compounds in the atmosphere; however, there are few reports about the halide profiles and strengths of these emissions. Halide ion methyltransferase (HMT) and halide/thiol methyltransferase (HTMT) enzymes concerning these emissions have been purified and characterized from several organisms including marine algae, fungi, and higher plants; however, the correlation between emission profiles of methyl halides and the enzymatic properties of HMT/HTMT, and their role in vivo remains unclear.</p> <p>Results</p> <p>Thirty-five higher plant species were screened, and high CH<sub>3</sub>I emissions and HMT/HTMT activities were found in higher plants belonging to the Poaceae family, including wheat (<it>Triticum aestivum </it>L.) and paddy rice (<it>Oryza sativa </it>L.), as well as the Brassicaceae family, including daikon radish (<it>Raphanus sativus</it>). The in vivo emission of CH<sub>3</sub>I clearly correlated with HMT/HTMT activity. The emission of CH<sub>3</sub>I from the sprouting leaves of <it>R. sativus</it>, <it>T. aestivum </it>and <it>O. sativa </it>grown hydroponically increased with increasing concentrations of supplied iodide. A gene encoding an <it>S</it>-adenosylmethionine halide/thiol methyltransferase (HTMT) was cloned from <it>R. sativus </it>and expressed in <it>Escherichia coli </it>as a soluble protein. The recombinant <it>R. sativus </it>HTMT (RsHTMT) was revealed to possess high specificity for iodide (I<sup>-</sup>), bisulfide ([SH]<sup>-</sup>), and thiocyanate ([SCN]<sup>-</sup>) ions.</p> <p>Conclusion</p> <p>The present findings suggest that HMT/HTMT activity is present in several families of higher plants including Poaceae and Brassicaceae, and is involved in the formation of methyl halides. Moreover, it was found that the emission of methyl iodide from plants was affected by the iodide concentration in the cultures. The recombinant RsHTMT demonstrated enzymatic properties similar to those of <it>Brassica oleracea </it>HTMT, especially in terms of its high specificity for iodide, bisulfide, and thiocyanate ions. A survey of biogenic emissions of methyl halides strongly suggests that the HTM/HTMT reaction is the key to understanding the biogenesis of methyl halides and methylated sulfur compounds in nature.</p

    マーシャルの部分均衡論と生産者余剰

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    We defended Marshall from modern economic theorists\u27 false accusation that he forgot producers\u27 surplus in his proposition of the tax-subsidy scheme. After due attention is paid to Brahmananda\u27s pioneering contribution, we argued, firstly, that Marshall did not forget producers\u27 surplus but merely considered the case of no producers\u27 surplus, in view of his distinction between the supply curve and the particular expenses curve and the long-run nature of the equilibrium considered. In addition to this purely theoretical vindication (rational reconstruction), we argued further more, from the view point of the history of economic thought, that Marshall did not forget producers\u27 surplus in The Pure Theory, which was aimed at specialist readers, but deliberately assumed it away in Principles, which was aimed at more general readers. Finally, in view of the recent rapid development of the theoretical and applied general equilibrmm theory, we emphasize the role of Marshallian particular equilibrium analysis as a heuristic method

    Delta-like 4 is indispensable in thymic environment specific for T cell development

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    The thymic microenvironment is required for T cell development in vivo. However, in vitro studies have shown that when hematopoietic progenitors acquire Notch signaling via Delta-like (Dll)1 or Dll4, they differentiate into the T cell lineage in the absence of a thymic microenvironment. It is not clear, however, whether the thymus supports T cell development specifically by providing Notch signaling. To address this issue, we generated mice with a loxP-flanked allele of Dll4 and induced gene deletion specifically in thymic epithelial cells (TECs). In the thymus of mutant mice, the expression of Dll4 was abrogated on the epithelium, and the proportion of hematopoietic cells bearing the intracellular fragment of Notch1 (ICN1) was markedly decreased. Corresponding to this, CD4 CD8 double-positive or single-positive T cells were not detected in the thymus. Further analysis showed that the double-negative cell fraction was lacking T cell progenitors. The enforced expression of ICN1 in hematopoietic progenitors restored thymic T cell differentiation, even when the TECs were deficient in Dll4. These results indicate that the thymus-specific environment for determining T cell fate indispensably requires Dll4 expression to induce Notch signaling in the thymic immigrant cells

    STM/STSによる金サブナノクラスターの電子構造の研究

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    2003年分子構造総合討論会, 2003年9月24日-27日, 京都テルサ(京都), 1Pp092本研究は、文部科学省のナノテクノロジー総合支援プロジェクトの支援を受けて実施されたものである

    STM/STSによる金サブナノクラスターの電子構造の研究

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    2003年分子構造総合討論会, 2003年9月24日-27日, 京都テルサ(京都), 1Pp092本研究は、文部科学省のナノテクノロジー総合支援プロジェクトの支援を受けて実施されたものである

    STM/STSによる金サブナノクラスターの電子構造の研究

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    2003年分子構造総合討論会, 2003年9月24日-27日, 京都テルサ(京都), 1Pp092本研究は、文部科学省のナノテクノロジー総合支援プロジェクトの支援を受けて実施されたものである

    STM/STSによる金サブナノクラスターの電子構造の研究

    Get PDF
    2003年分子構造総合討論会, 2003年9月24日-27日, 京都テルサ(京都), 1Pp092本研究は、文部科学省のナノテクノロジー総合支援プロジェクトの支援を受けて実施されたものである

    Structural and functional analyses of calcium ion response factors in the mantle of Pinctada fucata

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    The pearl oyster, Pinctada fucata, is cultured for pearl production in Japan. The shell of the pearl oyster consists of calcium carbonate and a small amount of organic matrix. Despite many studies of the shell matrix proteins, the mechanism by which calcium elements are transported from the mantle to the shell remains unclear. Investigating the molecular mechanism of calcium transportation, we prepared artificial seawater with a high concentration of calcium ions (10ASW) to induce calcification in the pearl oyster. When pearl oysters were cultured in 10ASW, unusual nanoparticles were precipitated on the surface of the nacreous layer. SDS-PAGE and 2D-PAGE analyses revealed that some calcium-sensing proteins (Sarcoplasmic Ca-binding Protein (Pf-SCP) and Pf-filamin A) might be related to the synthesis of these nanoparticles. The recombinant proteins of Pf-SCP can bind to calcium ions and accumulate nanoparticles of calcium carbonate crystals. However, transcriptomic analysis of the pearl oysters grown in 10ASW showed that the matrix protein genes in the shell did not differ before and after treatment with 10ASW. These results suggest that, despite increasing calcium transportation to the shell, treatment with a high concentration of calcium ions does not induce formation of the organic framework in the shell microstructure. These findings offer meaningful insights into the transportation of calcium elements from the mantle to the shell
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