1,470 research outputs found

    Application of precise 142Nd/144Nd analysis of small samples to inclusions in diamonds (Finsch, South Africa) and Hadean Zircons (Jack Hills, Western Australia)

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    146Sm-142Nd and 147Sm-143Nd systematics were investigated in garnet inclusions in diamonds from Finsch (S. Africa) and Hadean zircons from Jack Hills (W. Australia) to assess the potential of these systems as recorders of early Earth evolution. The stud

    A solenoidal electron spectrometer for a precision measurement of the neutron β\beta-asymmetry with ultracold neutrons

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    We describe an electron spectrometer designed for a precision measurement of the neutron β\beta-asymmetry with spin-polarized ultracold neutrons. The spectrometer consists of a 1.0-Tesla solenoidal field with two identical multiwire proportional chamber and plastic scintillator electron detector packages situated within 0.6-Tesla field-expansion regions. Select results from performance studies of the spectrometer with calibration sources are reported.Comment: 30 pages, 19 figures, 1 table, submitted to NIM

    Incompatibility Systems in Switchgrass

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    Switchgrass (Panicum virgatum L.), a cross-pollinated perennial, produces very little or no seed when self-pollinated, indicating the presence of self-incompatibility mechanisms. Knowledge of self-incompatibility mechanisms is required to use germplasm effectively in a breeding program. The objective of this study was to characterize features of the incompatibility systems in switchgrass. Seed set and seed characteristics of reciprocal matings of tetraploid, octaploid, and tetraploid x octaploid plants were used as measures of incompatibility. Both bagged mutual pollination and manual emasculation and pollination methods were used to make crosses. The percentages of self-compatibility in the tetraploid and octaploid parent plants were 0.35 and 1.39%, respectively. Prefertilization incompatibility in switchgrass is apparently under gametophytic control, since there were significant differences in percentage of compatible pollen as measured by percentage of total seed set between reciprocal matings within ploidy levels. Results indicated that the prefertilization incompatibility system in switchgrass is similar to the S-Z incompatibility system found in other members of the Poaceae. A postfertilization incompatibility system also exists that inhibits intermatings among octaploid and tetraploid plants. In these interploidy crosses, two very distinctive types of abnormal seed were found. When the female parent was the tetraploid plant, the resulting seed was small and shriveled, while when the female parent was the octaploid, small seed with floury endosperm was obtained. These results are similar to those obtained for endosperm incompatibility due to the endosperm balance number system found in other species

    Enhancing declarative debugging with loop expansion and tree compression

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    This work has been partially supported by the Spanish Ministerio de Econom´ıa y Competitividad (Secretar´ıa de Estado de Investigaci´on, Desarrollo e Innovaci´on) under grant TIN2008-06622-C03-02 and by the Generalitat Valenciana under grant PROMETEO/2011/052. David Insa was partially supported by the Spanish Ministerio de Eduaci´on under FPU grant AP2010-4415Insa Cabrera, D.; Silva Galiana, JF.; Tomás Franco, C. (2013). Enhancing declarative debugging with loop expansion and tree compression. En Logic-Based Program Synthesis and Transformation. Springer Verlag (Germany). 71-88. https://doi.org/10.1007/978-3-642-38197-3_6S7188Binks, D.: Declarative Debugging in Gödel. PhD thesis, University of Bristol (1995)Calejo, M.: A Framework for Declarative Prolog Debugging. PhD thesis, New University of Lisbon (1992)Davie, T., Chitil, O.: Hat-delta: One Right Does Make a Wrong. In: Butterfield, A. (ed.) Draft Proceedings of the 17th International Workshop on Implementation and Application of Functional Languages, IFL 2005, p. 11. Tech. Report No: TCD-CS-2005-60, University of Dublin, Ireland (September 2005)Davie, T., Chitil, O.: Hat-delta: One Right Does Make a Wrong. In: Seventh Symposium on Trends in Functional Programming, TFP 2006 (April 2006)Harrison, P.G., Khoshnevisan, H.: A new approach to recursion removal. Theor. Comput. Sci. 93(1), 91–113 (1992)Hirunkitti, V., Hogger, C.J.: A Generalised Query Minimisation for Program Debugging. In: Adsul, B. (ed.) AADEBUG 1993. LNCS, vol. 749, pp. 153–170. Springer, Heidelberg (1993)Insa, D., Silva, J.: An Algorithmic Debugger for Java. In: Proc. of the 26th IEEE International Conference on Software Maintenance, pp. 1–6 (2010)Insa, D., Silva, J.: Debugging with Incomplete and Dynamically Generated Execution Trees. In: Proc. of the 20th International Symposium on Logic-based Program Synthesis and Transformation, LOPSTR 2010, Austria (2010)Insa, D., Silva, J.: A Transformation of Iterative Loops into Recursive Loops. Technical Report DSIC/05/12, Universidad Politécnica de Valencia (2012), http://www.dsic.upv.es/~jsilva/research.htm#techsInsa, D., Silva, J., Tomás, C.: Enhancing Declarative Debugging with Loop Expansion and Tree Compression. Technical Report DSIC/11/12, Universidad Politécnica de Valencia (2012), http://www.dsic.upv.es/~jsilva/research.htm#techsLiu, Y.A., Stoller, S.D.: From recursion to iteration: what are the optimizations? In: Proceedings of the 2000 ACM SIGPLAN Workshop on Partial Evaluation and Semantics-Based Program Manipulation, PEPM 2000, pp. 73–82. ACM, New York (2000)Lloyd, J.W.: Declarative error diagnosis. New Gen. Comput. 5(2), 133–154 (1987)Nilsson, H.: Declarative Debugging for Lazy Functional Languages. PhD thesis, Linköping, Sweden (May 1998)NIST: The Economic Impacts of Inadequate Infrastructure for Software Testing. USA National Institute of Standards and Technology, NIST Planning Report 02-3 (May 2002)Riesco, A., Verdejo, A., Martí-Oliet, N., Caballero, R.: Declarative Debugging of Rewriting Logic Specifications. Journal of Logic and Algebraic Programming (September 2011)Shapiro, E.Y.: Algorithmic Program Debugging. MIT Press (1982)Silva, J.: A Survey on Algorithmic Debugging Strategies. Advances in Engineering Software 42(11), 976–991 (2011)Yi, Q., Adve, V., Kennedy, K.: Transforming loops to recursion for multi-level memory hierarchies. In: Proceedings of the SIGPLAN 2000 Conference on Programming Language Design and Implementation, pp. 169–181 (2000

    Natural Resource Protection and Petroleum Development in Alaska: A Summary

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    Performed for Office of Biological Services Fish and Wildlife Service U.S. Department of the Interior Contract No. 14-16-0009-79-123 Job No. 6347-011-2

    Extreme Ultra-Violet Spectroscopy of the Lower Solar Atmosphere During Solar Flares

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    The extreme ultraviolet portion of the solar spectrum contains a wealth of diagnostic tools for probing the lower solar atmosphere in response to an injection of energy, particularly during the impulsive phase of solar flares. These include temperature and density sensitive line ratios, Doppler shifted emission lines and nonthermal broadening, abundance measurements, differential emission measure profiles, and continuum temperatures and energetics, among others. In this paper I shall review some of the advances made in recent years using these techniques, focusing primarily on studies that have utilized data from Hinode/EIS and SDO/EVE, while also providing some historical background and a summary of future spectroscopic instrumentation.Comment: 34 pages, 8 figures. Submitted to Solar Physics as part of the Topical Issue on Solar and Stellar Flare

    Governing processes for reactive nitrogen compounds in the atmosphere in relation to ecosystem climatic and human health impacts

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    Reactive nitrogen (Nr) compounds have different fates in the atmosphere due to differences in governing processes of physical transport, deposition and chemical transformation. Nr compounds addressed here include reduced nitrogen (NHx: ammonia (NH3) and its reaction product ammonium (NH4+)), oxidized nitrogen (NOy: nitrogen monoxide (NO) + nitrogen dioxide (NO2) and their reaction products) as well as organic nitrogen compounds (organic N). Pollution abatement strategies need to take into account these differences in the governing processes of these compounds when assessing their impact on ecosystem services, biodiversity, human health and climate. NOx (NO + NO2) emitted from traffic affects human health in urban areas where the presence of buildings increases the residence time in streets. In urban areas this leads to enhanced exposure of the population to NOx concentrations. NOx emissions have little impact on nearby ecosystems because of the small dry deposition rates of NOx. These compounds need to be converted into nitric acid (HNO3) before removal through deposition is efficient. HNO3 sticks quickly to any surface and is thereby either dry deposited or incorporated into aerosols as nitrate (NO3−). In contrast to NOx compounds, NH3 has potentially high impacts on ecosystems near the main agricultural sources of NH3 because of its large ground-level concentrations along with large dry deposition rates. Aerosol phase NH4+ and NO3− contribute significantly to background PM2.5 and PM10 (mass of aerosols with a diameter of less than 2.5 and 10 μm, respectively) with an impact on radiation balance as well as potentially on human health. Little is known quantitatively and qualitatively about organic N in the atmosphere, other than that it contributes a significant fraction of wet-deposited N, and is present in both gaseous and particulate forms in the atmosphere. Further studies are needed to characterize the sources, air chemistry and removal rates of organic N emissions

    Nature of Sonoluminescence: Noble Gas Radiation Excited by Hot Electrons in "Cold" Water

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    We show that strong electric fields occurring in water near the surface of collapsing gas bubbles because of the flexoelectric effect can provoke dynamic electric breakdown in a micron-size region near the bubble and consider the scenario of the SBSL. The scenario is: (i) at the last stage of incomplete collapse of the bubble the gradient of pressure in water near the bubble surface has such a value and sign that the electric field arising from the flexoelectric effect exceeds the threshold field of the dynamic electrical breakdown of water and is directed to the bubble center; (ii) mobile electrons are generated because of thermal ionization of water molecules near the bubble surface; (iii) these electrons are accelerated in ''cold'' water by the strong electric fields; (iv) these hot electrons transfer noble gas atoms dissolved in water to high-energy excited states and optical transitions between these states produce SBSL UV flashes in the trasparency window of water; (v) the breakdown can be repeated several times and the power and duration of the UV flash are determined by the multiplicity of the breakdowns. The SBSL spectrum is found to resemble a black-body spectrum where temperature is given by the effective temperature of the hot electrons. The pulse energy and some other characteristics of the SBSL are found to be in agreement with the experimental data when realistic estimations are made.Comment: 11 pages (RevTex), 1 figure (.ps

    Renormalization Group Running of Lepton Mixing Parameters in See-Saw Models with S4S_4 Flavor Symmetry

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    We study the renormalization group running of the tri-bimaximal mixing predicted by the two typical S4S_4 flavor models at leading order. Although the textures of the mass matrices are completely different, the evolution of neutrino mass and mixing parameters is found to display approximately the same pattern. For both normal hierarchy and inverted hierarchy spectrum, the quantum corrections to both atmospheric and reactor neutrino mixing angles are so small that they can be neglected. The evolution of the solar mixing angle θ12\theta_{12} depends on tan⁥β\tan\beta and neutrino mass spectrum, the deviation from its tri-bimaximal value could be large. Taking into account the renormalization group running effect, the neutrino spectrum is constrained by experimental data on θ12\theta_{12} in addition to the self-consistency conditions of the models, and the inverted hierarchy spectrum is disfavored for large tan⁥β\tan\beta. The evolution of light-neutrino masses is approximately described by a common scaling factor.Comment: 23 pages, 6figure
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