282 research outputs found

    Pointwise consistency of the kriging predictor with known mean and covariance functions

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    This paper deals with several issues related to the pointwise consistency of the kriging predictor when the mean and the covariance functions are known. These questions are of general importance in the context of computer experiments. The analysis is based on the properties of approximations in reproducing kernel Hilbert spaces. We fix an erroneous claim of Yakowitz and Szidarovszky (J. Multivariate Analysis, 1985) that the kriging predictor is pointwise consistent for all continuous sample paths under some assumptions.Comment: Submitted to mODa9 (the Model-Oriented Data Analysis and Optimum Design Conference), 14th-19th June 2010, Bertinoro, Ital

    CMB photons shedding light on dark matter

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    The annihilation or decay of Dark Matter (DM) particles could affect the thermal history of the universe and leave an observable signature in Cosmic Microwave Background (CMB) anisotropies. We update constraints on the annihilation rate of DM particles in the smooth cosmological background, using WMAP7 and recent small-scale CMB data. With a systematic analysis based on the Press-Schechter formalism, we also show that DM annihilation in halos at small redshift may explain entirely the reionization patterns observed in the CMB, under reasonable assumptions concerning the concentration and formation redshift of halos. We find that a mixed reionization model based on DM annihilation in halos as well as star formation at a redshift z~6.5 could simultaneously account for CMB observations and satisfy constraints inferred from the Gunn-Peterson effect. However, these models tend to reheat the inter-galactic medium (IGM) well above observational bounds: by including a realistic prior on the IGM temperature at low redshift, we find stronger cosmological bounds on the annihilation cross-section than with the CMB alone.Comment: 35 pages, 14 figures; version accepted in JCAP after minor revision

    Numerical solution to the hermitian Yang-Mills equation on the Fermat quintic

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    We develop an iterative method for finding solutions to the hermitian Yang-Mills equation on stable holomorphic vector bundles, following ideas recently developed by Donaldson. As illustrations, we construct numerically the hermitian Einstein metrics on the tangent bundle and a rank three vector bundle on P^2. In addition, we find a hermitian Yang-Mills connection on a stable rank three vector bundle on the Fermat quintic.Comment: 25 pages, 2 figure

    ASCR/HEP Exascale Requirements Review Report

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    This draft report summarizes and details the findings, results, and recommendations derived from the ASCR/HEP Exascale Requirements Review meeting held in June, 2015. The main conclusions are as follows. 1) Larger, more capable computing and data facilities are needed to support HEP science goals in all three frontiers: Energy, Intensity, and Cosmic. The expected scale of the demand at the 2025 timescale is at least two orders of magnitude -- and in some cases greater -- than that available currently. 2) The growth rate of data produced by simulations is overwhelming the current ability, of both facilities and researchers, to store and analyze it. Additional resources and new techniques for data analysis are urgently needed. 3) Data rates and volumes from HEP experimental facilities are also straining the ability to store and analyze large and complex data volumes. Appropriately configured leadership-class facilities can play a transformational role in enabling scientific discovery from these datasets. 4) A close integration of HPC simulation and data analysis will aid greatly in interpreting results from HEP experiments. Such an integration will minimize data movement and facilitate interdependent workflows. 5) Long-range planning between HEP and ASCR will be required to meet HEP's research needs. To best use ASCR HPC resources the experimental HEP program needs a) an established long-term plan for access to ASCR computational and data resources, b) an ability to map workflows onto HPC resources, c) the ability for ASCR facilities to accommodate workflows run by collaborations that can have thousands of individual members, d) to transition codes to the next-generation HPC platforms that will be available at ASCR facilities, e) to build up and train a workforce capable of developing and using simulations and analysis to support HEP scientific research on next-generation systems.Comment: 77 pages, 13 Figures; draft report, subject to further revisio

    The Effect of Raw Soybeans in Mixtures for Laying Hens on Egg Quality and Egg Shell Quality

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    The study was conducted on hens at the age of 49 - 57 weeks to identify opportunities for replacing, with raw grain, thermally processed soybean Lana variety with a reduced level and Lydia variety with a standard level of trypsin inhibitor. The effect of using different levels of participation of both varieties of raw soybean in mixtures for layers on egg quality and eggshell quality was examined. The research was conducted according to the principle of two-factorial experiment (2 varieties x 4 levels of participation of raw soybeans). The average values of properties of the external and internal egg quality were under statistically significant influence of the level of participation of raw soybean in the mixture. Share of 8 % of raw soybeans of both varieties in diets for layers influenced significantly lower eggshape index, albumen height and Haugh's unit in relation to the mixture with a lower level of participation of raw soybeans. Yolk color and eggshell firmness were not significantly influenced by the studied factors

    Correlations Between Incidence of Foot Pad Lesions and Body Weight of Broilers in Different Rearing Systems

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    The incidence of foot pad lesions of broilers of moderate growth was investigated in order to establish correlations with body weight. Broilers were reared until the age of 42 days in the floor system in the poultry house and then were divided into two groups. The first group continued growing in the poultry house until the age of 84 days and the second group was growing in the free range system until the same age. Individual measurements of body weight and evaluation of the incidence of foot pad lesions of broilers were carried out at the end of the experiment. In a correlation analysis of previously transformed data on the percentage of broilers with lesions and body weight within each weight group, data were obtained that showed an association between these traits depending on the rearing system. System of rearing had significant impact on the strength and direction of correlation between body weight and the incidence of foot pad lesions, in light of the determined correlation coefficient r = -0.95 at the significance level p=0.01 in the free range system, and r=0.56 (p>0.05) in chickens reared in the poultry house

    ECFA Detector R&D Panel, Review Report

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    Two special calorimeters are foreseen for the instrumentation of the very forward region of an ILC or CLIC detector; a luminometer (LumiCal) designed to measure the rate of low angle Bhabha scattering events with a precision better than 103^{-3} at the ILC and 102^{-2} at CLIC, and a low polar-angle calorimeter (BeamCal). The latter will be hit by a large amount of beamstrahlung remnants. The intensity and the spatial shape of these depositions will provide a fast luminosity estimate, as well as determination of beam parameters. The sensors of this calorimeter must be radiation-hard. Both devices will improve the e.m. hermeticity of the detector in the search for new particles. Finely segmented and very compact electromagnetic calorimeters will match these requirements. Due to the high occupancy, fast front-end electronics will be needed. Monte Carlo studies were performed to investigate the impact of beam-beam interactions and physics background processes on the luminosity measurement, and of beamstrahlung on the performance of BeamCal, as well as to optimise the design of both calorimeters. Dedicated sensors, front-end and ADC ASICs have been designed for the ILC and prototypes are available. Prototypes of sensor planes fully assembled with readout electronics have been studied in electron beams.Comment: 61 pages, 51 figure

    Sinteza i karakterizacija kompleksa cink(II), kadmijum(II), platina(II),i paladijum(II) sa kalijum-3-ditiokarboksi-3-aza-5-aminopentanoatom

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    Complexes of zinc(lI), cadmium(II). platinum(lI) and palladium(II) with a new poly-dentate dithiocarbamate ligand, 3-dithiocarboxy-3-aza-5-aminopentanoate (daap(-)), of the type M(daap)(2).nH(2)O (M = Zn(II), Cd(II), n = 2, or M = Pt(II) Pd(II) n = 0). have been prepared and characterized by elemental analysis. IR and UV/VIS spectroscopy, as well as magnetic measurements. The spectra of the complexes suggest a bidentate coordination of the daap- ligand to the metal ions via the sulfur atoms of the deprotonated dithiocarbamato group. The fact that under the same experimental conditions its S-methyl ester does not form complexes could be taken as proof of the suggested coordination mode.Reakcijom između cink(II), kadmijum(II), platina(II) i paladijum(II)-soli i kalijum- 3-ditiokarboksi-3-aza-5-aminopentanoata dobijeni su dogovarajući kompleksi tipa M(daap)2.nH2O. Izolovani kompleksi su okarakterisani elementarnom analizom, IR i UV/VIS spektroskopijom kao i merenjem magnetnih susceptibiliteta. Spektri kompleksa sugerišu bidentatnu koordinaciju daap liganda sa navedenim metalnim jonima preko atoma sumpora deprotonovane ditiokarbamato grupe. Kao dokaz navedenog načina koordinacije može poslužiti činjenica da pri istim eksperimentalnim uslovima S-metil estar liganda ne daje komplekse
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