280 research outputs found

    The Principles of Exchange Rate Determination in an International Finance Experiment

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    This paper reports the first experiments designed to explore the behavior of economies with prominent features of international finance. Two “countries,” each with its own currency, were created. International trade could take place only through the operation of markets for currency. The law of one price and the flow of funds theory of exchange rate determination were used to produce general equilibrium models that captured much of the behavior of the economies. Prices of goods, as well as the exchange rate, evolve over time toward the predictions of the models. However, both the law of one price and purchasing power parity can be rejected for reasons that do not appear in the literature. Patterns of international trade were as predicted by the law of comparative advantage

    Storeable Votes: Giving Voice to Minority Preferences Without Sacrificing Efficiency

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    [Introduction] The principle of majority rule is the foundation of democratic constitutions, but provides an immediate and fundamental challenge to the legitimacy of any government that the constitution empowers: the risk of excluding minority groups from representation. At least since Madison, Mill, and Tocqueville, political thinkers have argued that a necessary condition for the legitimacy of a democratic system is for no group with socially acceptable goals to be disenfranchised. In the history of constitutional law, ensuring fair representation to each group is seen as the crucial second step in the evolution of democratic institutions, after granting the franchise: once all individuals are guaranteed the right to participate in the political process, the problem remains how to assign appropriate weights to each group’s political interest.The core of the difficulty is that the two goals seem inherently contradictory

    The small GTPase Arf1 regulates ATP synthesis and mitochondria homeostasis by modulating fatty acid metabolism

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    Lipid mobilization through fatty acid ÎČ-oxidation is a central process essential for energy 36 production during nutrient shortage. In yeast, this catabolic process starts in the peroxisome from where ÎČ-oxidation products enter mitochondria and fuel the TCA cycle. Little is known about the physical and metabolic cooperation between these organelles. We found that expression of fatty acid transporters and of the rate-limiting enzyme involved in ÎČ-oxidation are decreased in cells expressing a hyperactive mutant of the small GTPase Arf1, leading to an accumulation of fatty acids in lipid droplets. As a consequence, mitochondria became fragmented and ATP synthesis decreased. Genetic and pharmacological depletion of fatty acids phenocopied the arf1 mutant mitochondrial phenotype. Although ÎČ-oxidation occurs mainly in mitochondria in mammals, Arf1's role in fatty acid metabolism is conserved. Together, our results indicate that Arf1 integrates metabolism into energy production by regulating fatty acid storage and utilization, and presumably organelle contact-sites

    An Experimental Investigation of the Patterns of International Trade

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    This paper studies a laboratory economy with some of the prominent features of an international economic system. The patterns of trade and output predicted by the law of comparative advantage are observed evolving within the experimental markets. Market prices and quantities move in the direction of the competitive equilibrium, but the quantitative predictions of the (risk neutral) competitive equilibrium are rejected. Considerable amounts of economic activity occur as disequilibria. Factor-price equalization is observed, but there is a universal tendency for factors of production to trade at prices below their marginal products

    Mitochondrial precursor proteins are imported through a hydrophilic membrane environment

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    We have analyzed how translocation intermediates of imported mitochondrial precursor proteins, which span contact sites, interact with the mitochondrial membranes. F1-ATPase subunit ÎČ(F1ÎČ) was trapped at contact sites by importing it into Neurospora mitochondria in the presence of low levels of nucleoside triphosphates. This F1ÎČ translocation intermediate could be extracted from the membranes by treatment with protein denaturants such as alkaline pH or urea. By performing import at low temperatures, the ADP/ATP carrier was accumulated in contact sites of Neurospora mitochondria and cytochrome b2 in contact sites of yeast mitochondria. These translocation intermediates were also extractable from the membranes at alkaline pH. Thus, translocation of precursor proteins across mitochondrial membranes seems to occur through an environment which is accessible to aqueous perturbants. We propose that proteinaceous structures are essential components of a translocation apparatus present in contact sites

    The SwissLipids knowledgebase for lipid biology.

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    MOTIVATION: Lipids are a large and diverse group of biological molecules with roles in membrane formation, energy storage and signaling. Cellular lipidomes may contain tens of thousands of structures, a staggering degree of complexity whose significance is not yet fully understood. High-throughput mass spectrometry-based platforms provide a means to study this complexity, but the interpretation of lipidomic data and its integration with prior knowledge of lipid biology suffers from a lack of appropriate tools to manage the data and extract knowledge from it. RESULTS: To facilitate the description and exploration of lipidomic data and its integration with prior biological knowledge, we have developed a knowledge resource for lipids and their biology-SwissLipids. SwissLipids provides curated knowledge of lipid structures and metabolism which is used to generate an in silico library of feasible lipid structures. These are arranged in a hierarchical classification that links mass spectrometry analytical outputs to all possible lipid structures, metabolic reactions and enzymes. SwissLipids provides a reference namespace for lipidomic data publication, data exploration and hypothesis generation. The current version of SwissLipids includes over 244 000 known and theoretically possible lipid structures, over 800 proteins, and curated links to published knowledge from over 620 peer-reviewed publications. We are continually updating the SwissLipids hierarchy with new lipid categories and new expert curated knowledge. AVAILABILITY: SwissLipids is freely available at http://www.swisslipids.org/. CONTACT: [email protected] SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online
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