13,618 research outputs found

    Multipurpose microcontroller design for PUGAS 2

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    This paper will report on the past year's work on the development of the microcontroller design for the second Purdue University small self-contained payload. A first report on this effort was given at last year's conference by Ritter (1985). At that time, the project was still at the conceptual stage. Now a specific design has been set, prototyping has begun, and layout of the two-sided circuit board using CAD-techniques is nearing completion. A redesign of the overall concept of the circuit board was done to take advantage of the facilities available to students. An additional controller has been added to take large quantities of data concerning the shuttle environment during takeoff. The importance of setting a design time-line is discussed along with the electrical design considerations given to the controllers

    Nonlinearities and Parametric Amplification in Superconducting Coplanar Waveguide Resonators

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    Experimental investigations of the nonlinear properties of superconducting niobium coplanar waveguide resonators are reported. The nonlinearity due to a current dependent kinetic inductance of the center conductor is strong enough to realize bifurcation of the nonlinear oscillator. When driven with two frequencies near the threshold for bifurcation, parametric amplification with a gain of +22.4 dB is observed.Comment: 4 pages, 5 figures, 1 table. In version 2: Added appendix with model description and fits to measurements. Minor corrections and rephrasin

    The Variation of the Compass for the Year 1960

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    Vanadium dioxide : A Peierls-Mott insulator stable against disorder

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    Vanadium dioxide undergoes a first order metal-insulator transition at 340 K. In this work, we develop and carry out state of the art linear scaling DFT calculations refined with non-local dynamical mean-field theory. We identify a complex mechanism, a Peierls-assisted orbital selection Mott instability, which is responsible for the insulating M1_1 phase, and furthermore survives a moderate degree of disorder.Comment: 5 pages, 4 figures. Supplementary material 8 pages, 4 figures. This version (v2) matches that accepted for Physical Review Letters on 16th May 201

    High-throughput colorimetric method for the parallel assay of glyoxylic acid and ammonium in a single extract

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    Bräutigam A, Gagneul D, Weber APM. High-throughput colorimetric method for the parallel assay of glyoxylic acid and ammonium in a single extract. Analytical Biochemistry. 2007;362(1):151-153

    Market-Oriented Strategies to Improve Household Access to Food: Experience from Sub-Saharan Africa

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    The objectives of this report are to identify market-oriented strategies to alleviate both chronic and transitory food insecurity, and to examine the interactions between short-run targeting mechanisms and longer-run strategies designed to alleviate the chronic causes of inadequate access to food. The main premise of the report is that sustained improvements in household access to food in Sub-Saharan Africa require the development of more reliable food and input markets that (a) create incentives to adopt cost-reducing investments at various stages in the food system; and (b) offer incentives for rural households to shift from a subsistence-oriented pattern of production and consumption to more productive systems based on specialization and gains from exchange. Sustained productivity growth in most parts of the world has typically entailed some form of structural transformation, which, in the historical development processes of other regions, has been a prerequisite for broad-based and sustained growth in productivity, real incomes and purchasing power throughout society. Structural transformation involves a movement away from subsistence-oriented, household-level production toward an integrated economy based on specialization and exchange. But specialization makes households dependent on the performance of exchange systems. The ability to capture the productivity gains from new technology and specialization thus depends on reducing the risks and uncertainty of market-based exchange, thereby facilitating greater participation in the types of specialized production and consumption patterns involved in the process of structural transformation. Section 3 presents empirical evidence from research conducted in Africa to draw conclusions about how the design of agricultural policies and transfer programs have affected household access to food in both rural and urban areas. Based on the foregoing, section 4 presents the following guidelines for the design of strategies to promote access to food in Africa: (1.) Focus on achieving productivity gains in the food system. (2.) Focus on how food and income transfer programs can be designed to promote the long-run development of the food system- the basis for providing food for most people over the long run in addition to providing food to people in the short run. (3.) Focus on reducing consumer food costs by expanding the range of products available to produce and consume. (4.) Focus on the cost and reliability of food supplies to rural areas as a component of non-farm, livestock, and other income diversification strategies designed to promote access to food over the longer run. (5.) Focus on developing local analytical expertise to help guide food system development.Food Security and Poverty, Downloads July 2008-June 2009: 12,

    Colorectal cancer screening and subsequent incidence of colorectal cancer: Results from the 45 and Up Study

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    Objective: To investigate the association of colorectal cancer (CRC) screening history and subsequent incidence of CRC in New South Wales, Australia. Design, setting and participants: A total of 196 464 people from NSW recruited to the 45 and Up Study,

    Does Distance Matter? The Influence of ICT on Bilateral Trade Flows

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    Information and communication technology (ICT) has altered previous notions of distance and led to discussions in the popular press of the “death of distance.” Geographic distance typically results in diminished trade flows between countries, but does ICT play a role in overcoming geographic distance? This article examines the key hypothesis that ICT reduces the cost associated with the conduct of international trade between distant countries. In this research, we examine bilateral trade flows and geographic distance data for 175 different countries. We use a gravitational model to determine if physical and cultural distance matters in how ICT affects bilateral trade flows. Our methodology involves the use of 14,511 country pairs, for which we can represent and evaluate the effects of our distance measures. We find that greater bilateral trade flows occur between countries with higher Internet use, suggesting that the presence of common digital infrastructure between countries will enhance their trade. We also found that ICT use has a more positive impact on bilateral trade flows between large economies than it does for smaller economies. Finally, ICT use by more distant trading partners appears to have a more positive impact on trade than it does on countries that are nearer to one another

    Ariel - Volume 4 Number 4

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    Editors David A. Jacoby Eugenia Miller Tom Williams Associate Editors Paul Bialas Terry Burt Michael Leo Gail Tenikat Editor Emeritus and Business Manager Richard J. Bonnano Movie Editor Robert Breckenridge Staff Richard Blutstein Mary F. Buechler Meg Brunt Steve Glinks Len Grasman Alice M. Johnson J.D. Kanofsky Tom Lehman Dave Mayer Bernie Odd
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