2,626 research outputs found

    Changing French Orientalism

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    Cataloged from PDF version of article.The article focuses on the story of the opera "Tarare," which became prevalent throughout Europe from 1760 to 1780. She examines the story of the opera, which centers the life of a Christian noblewoman who was abducted by an oriental potentate and must be rescued by her lover. However, the author points out that opera illustrate the complex discursive genealogy of French political, social, and philosophical concerns in the final quarter of the 18th century

    Hacia un enfoque más crítico del trabajo de laboratorio

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    The tradition which has assumed since the past century the central role of practical work in science education, is argued in this paper. The author reviews the assumptions that justify the educational benefits of practical work, and he does a critical scrutiny of its use and misuse in science education

    Role of Insects and Diseases in a Jack Pine Provenance Study

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    Two jack pine plantations were established at the Cloquet Forestry Center, Cloquet, Minnesota, in 1942 and 1943, using trees originating from 22 sites in the United States and 10 in Canada. From 1945 to 1953 the incidence of attack by insects and diseases was recorded individually for all trees, and in 1980-1981 the diameter and form of both living and dead trees were recorded. There were differences in the incidence of attack by the pests and in tree response to early injury among the various seed sources. In 1980 and in 1981 there were differences in tree form resulting from insect and both living and dead pest-free trees had the best form. The diameter increases from 1955 to 1980-1981 were almost identical for all categories with the exception of the dead pest-free trees which had the smallest diameters

    Triple mode Cepheid masses

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    Unconventional composition structures are proposed to explain the periods of the triple mode Cepheid aC And. A strong Cepheid wind appears to enrich helium in the convection zones down to about 60,000 K or 70,000 K. Then some downward partial mixing occurs to the bottom of a layer with about 1-q = .0005 of the stellar mass. It was found that AC And was not unlike anomalous Cepheids. However, masses of betwen one and two solar masses are suggested and the population is more likely a type two

    A Low Cost Remote Sensing System Using PC and Stereo Equipment

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    A system using a personal computer, speaker, and a microphone is used to detect objects, and make crude measurements using a carrier modulated by a pseudorandom noise (PN) code. This system can be constructed using a personal computer and audio equipment commonly found in the laboratory or at home, or more sophisticated equipment that can be purchased at reasonable cost. We demonstrate its value as an instructional tool for teaching concepts of remote sensing and digital signal processing.Comment: Accepted for publication in American Journal of Physic

    Copper Toxicity in Erwinia amylovora : An X-Ray Microanalytical Study

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    The effect of Cu2+ ions on the growth and elemental composition of the phytopathogenic bacterium Erwinia amylovora was investigated by in vitro culture in nutrient broth supplemented with CuSO4. No detectable inhibition in bacterial growth occurred with medium supplemented at 10-4M Cu (compared to control medium with no added Cu), but partial inhibition occurred at 10-3M Cu (limiting toxicity) and complete inhibition at 10-2M Cu. Under conditions of limiting toxicity, incubation in Cu2+ ions leads to a reduction in the general synthesis of cell materials and the formation of abnormally large cells with a small dry mass. X-ray analysis revealed the uptake of small levels of Cu2+ under these conditions, plus wide-ranging changes in other major elements present in the bacterial cells. These changes included a reduction in the level of K and increased levels of the divalent cations Ca and Fe. The results obtained are consistent with the toxic effect of Cu being mediated via its effect on the cell membrane, with internal elemental changes resulting from a perturbation of membrane permeability

    Modeling Quantum Optical Components, Pulses and Fiber Channels Using OMNeT++

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    Quantum Key Distribution (QKD) is an innovative technology which exploits the laws of quantum mechanics to generate and distribute unconditionally secure cryptographic keys. While QKD offers the promise of unconditionally secure key distribution, real world systems are built from non-ideal components which necessitates the need to model and understand the impact these non-idealities have on system performance and security. OMNeT++ has been used as a basis to develop a simulation framework to support this endeavor. This framework, referred to as "qkdX" extends OMNeT++'s module and message abstractions to efficiently model optical components, optical pulses, operating protocols and processes. This paper presents the design of this framework including how OMNeT++'s abstractions have been utilized to model quantum optical components, optical pulses, fiber and free space channels. Furthermore, from our toolbox of created components, we present various notional and real QKD systems, which have been studied and analyzed.Comment: Published in: A. F\"orster, C. Minkenberg, G. R. Herrera, M. Kirsche (Eds.), Proc. of the 2nd OMNeT++ Community Summit, IBM Research - Zurich, Switzerland, September 3-4, 201
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