183,229 research outputs found

    The early role of nitric oxide in evolution

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    Nitric oxide (NO), which today serves many different purposes in regulating complex cellular functions, must have played a crucial role in the early stages of the evolution of life. The formation of NO may have been a critical defence mechanism for primitive microorganisms at a time when life faced the problem of rising atmospheric levels of ozone (03) formed upon photolysis of oxygen (Oz), which occurred shortly after the development of respiration in cyanobacteria. The production of NO by organisms would have allowed neutralization of toxic 03 by chemical reaction outside the cell, thus acting as a protective mechanism against oxidative destruction, allowing evolutionary advantage. Later, NO production might have allowed the control of reactive OZ species within cells before the development of specific electron-accepting enzymes. The pathway of NO formation was then consequently developed further to serve other useful functions. Although mammalian cells produce NO from L-arginine, the origin of this ability might have arisen from the essential process of either nitrification or denitrification in prokaryotic cells

    Georgia's Corporate Taxes: Should the Corporate Income Tax be Repealed?

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    An analysis prepared for the Georgia Public Policy Foundation

    French Canadian Participation in the War of 1812: A Social Study of the Voltiguers Canadians

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    During the War of 1812, the participation of French Canadians in colonial militia units such as the Voltigeurs Canadiens was of great importance for the defence of Lower Canada. The colony’s lack of regular British toops combined with threats of American invasion rendered crucial to the mobilization of the local populace, most of which was of French descent. Although lacking the discipline and structure of British regular soldiers. Lower-Canadian militiamen were able to neutralize numerous American invasion attempts. Altogether, this impressive participation in the war effort helped redefine the military character of French Canadians. It also dissipated the British authorities’ fears that French Canadians were disloyal subjects. This study analyses the military organization of the Voltigeurs Canadiens to demonstrate the importance of French Canadian participation in the war, especially in Lower Canada, their military campaigns and how the Voltigeurs’ victories became the pride of all French Canada

    Does Georgia Need A Unitary Tax?

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    Abstract not available. Report #9

    Competition between finite-size effects and dipole-dipole interactions in few-atom systems

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    In this paper, we study the competition between finite-size effects (i.e. discernibility of particles) and dipole-dipole interactions in few-atom systems coupled to the electromagnetic field in vacuum. We consider two hallmarks of cooperative effects, superradiance and subradiance, and compute for each the rate of energy radiated by the atoms and the coherence of the atomic state during the time evolution. We adopt a statistical approach in order to extract the typical behavior of the atomic dynamics and average over random atomic distributions in spherical containers with prescribed k0Rk_0R with k0k_0 the radiation wavenumber and RR the average interatomic distance. Our approach allows us to highlight the tradeoff between finite-size effects and dipole-dipole interactions in superradiance/subradiance. In particular, we show the existence of an optimal value of k0Rk_0R for which the superradiant intensity and coherence pulses are the less affected by dephasing effects induced by dipole-dipole interactions and finite-size effects.Comment: 11 pages, 11 figure

    An improved architecture for the adaptive discrete cosine transform

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    Abstraction and registration: conceptual innovations and supply effects in Prussian and British Copyright (1820-50)

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    It is one of the orthodoxies of modern copyright law that the enjoyment and the exercise of the rights granted “shall not be subject to any formality” (Berne Convention 1886, Berlin revision 1908, Art.4), such as a registration requirement. In this article, we trace the origins of this provision to a conceptual shift that took place during the early 1800s. Specific regulations of the book trade were superseded by the protection of all instantiations (such as performances, translations and adaptations) of abstract authored work. For two seminal copyright acts of the period, the Prussian Act of 1837 and the UK Act of 1842, we show there was considerable concern about the economic implications of this new justificatory paradigm, reflected in a period of experimentation with sophisticated registration requirements. We indicate market responses to these requirements and plea for a reconsideration of “formalities” as redressing justificatory problems of copyright in the digital environment

    Global differential geometry: An introduction for control engineers

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    The basic concepts and terminology of modern global differential geometry are discussed as an introduction to the Lie theory of differential equations and to the role of Grassmannians in control systems analysis. To reach these topics, the fundamental notions of manifolds, tangent spaces, vector fields, and Lie algebras are discussed and exemplified. An appendix reviews such concepts needed for vector calculus as open and closed sets, compactness, continuity, and derivative. Although the content is mathematical, this is not a mathematical treatise but rather a text for engineers to understand geometric and nonlinear control
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