27,934 research outputs found

    Issues Affecting Security Design Pattern Engineering

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    Security Design Patterns present the tried and tested design decisions made by security engineers within a well documented format. Patterns allow for complex security concepts, and mechanisms, to be expressed such that non domain experts can make use of them. Our research is concerned with the development of pattern languages for advanced crypto-systems. From our experience developing pattern languages we have encountered several recurring issues within security design pattern engineering. These issues, if not addressed, will affect the adoption of security design patterns. This paper describes these issues and discusses how they could be addressed

    How Non-Research Investments Affect Research Impact: The Case of Maize Technology Adoption in Southern Mali

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    Crop Production/Industries, Research and Development/Tech Change/Emerging Technologies,

    Weighting CMB and Galactic synchrotron polarisation

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    We review the present knowledge of the diffuse Galactic synchrotron emission in polarisation. At microwave frequencies, we assess the expected contamination to the CMB polarisation angular power spectrum, for EE and BB modes, as expected after the WMAP first year measurements.Comment: 6 pages, 4 figures, proc. of the CMBnet workshop, 20-21 Feb. 2003, Oxford, U

    Modelling the effect of nuclear motion on the attosecond time-resolved photoelectron spectra of ethylene

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    Using time dependent density functional theory (TDDFT) we examine the energy, angular and time-resolved photoelectron spectra (TRPES) of ethylene in a pump-probe setup. To simulate TRPES we expose ethylene to an ultraviolet (UV) femtosecond pump pulse, followed by a time delayed extreme ultraviolet (XUV) probe pulse. Studying the photoemission spectra as a function of this delay provides us direct access to the dynamic evolution of the molecule's electronic levels. Further, by including the nuclei's motion, we provide direct chemical insight into the chemical reactivity of ethylene. These results show how angular and energy resolved TRPES could be used to directly probe electron and nucleus dynamics in molecules.Comment: 9 pages, 6 figure

    Improved Pseudofermion Approach for All-Point Propagators

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    Quark propagators with arbitrary sources and sinks can be obtained more efficiently using a pseudofermion method with a mode-shifted action. Mode-shifting solves the problem of critical slowing down (for light quarks) induced by low eigenmodes of the Dirac operator. The method allows the full physical content of every gauge configuration to be extracted, and should be especially helpful for unquenched QCD calculations. The method can be applied for all the conventional quark actions: Wilson, Sheikoleslami-Wohlert, Kogut-Susskind, as well as Ginsparg-Wilson compliant overlap actions. The statistical properties of the method are examined and examples of physical processes under study are presented.Comment: LateX, 26 pages, 10 eps figure

    Agricultural Research Impact Assessment: The Case of Maize Technology Adoption in Southern Mali

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    Adoption of the improved maize package was particularly rapid during the period 1980-86 when an attractive guaranteed price was offered and extension activities were reinforced by a maize project that included the establishment of a seed multiplication program. Following cereal market price liberalization in 1986, maize prices fell and have been subject to considerable variability. Area has continued to expand, but farmers have greatly reduced fertilizer use, switched back to maize-late millet intercropping, and substituted early maturing varieties better suited to their own food security needs. The estimated internal rate of return (IRR) to investment in maize research and extension in southern Mali over the period 1969-90 is 135%. This high rate can be attributed to low research costs (much of the technical package was borrowed from research conducted elsewhere in West Africa), and the high economic value of maize as an import substitute. Sensitivity analysis indicates that the IRR is robust with respect to adverse changes in assumptions concerning overvaluation of the exchange rate, research costs, extension costs, and area of improved maize. It is moderately sensitive to price and yield reductions.food security, food policy, maize, Crop Production/Industries, Research and Development/Tech Change/Emerging Technologies, Downloads June 2008 - June 2009: 26, R11,

    Cotton Sector Policies and Performance in Sub-Saharan Africa: Lessons Behind the Numbers in Mozambique and Zambia

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    Research results from SIMA-Department of Statistics and Department of Policy Analysis MADER-Directorate of Economicsfood security, food policy, cotton, Mozambique, Zambia, Crop Production/Industries, Q18,

    Vacuum decay along supersymmetric flat directions

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    It has been recently realized that within the Minimal Supersymmetric Standard Model, for certain patterns of superpartner masses, consistent with all the present experimental constraints, the scalar potential may develop at some scale Q0Q_0 unbounded color/charge breaking directions involving the sfermion fields, and that these patterns are then excluded unless some new physics is invoked at or below the scale Q0Q_0. We reanalyze this observation and point out that such patterns of superpartner masses at the weak scale are {\it not} ruled out when taking into account the probability of decay for the metastable color conserving minimum along these color breaking unbounded directions. It turns out that the color conserving minimum, although metastable, has a lifetime longer than the present age of the Universe and can survive both quantum tunneling and the effects of high temperatures in the early Universe, causing the color/charge breaking effects to be in practice not dangerous.Comment: 12 pages, uuencoded latex file + 4 ps figure
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