30,350 research outputs found

    Confidence Statements for Ordering Quantiles

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    This work proposes Quor, a simple yet effective nonparametric method to compare independent samples with respect to corresponding quantiles of their populations. The method is solely based on the order statistics of the samples, and independence is its only requirement. All computations are performed using exact distributions with no need for any asymptotic considerations, and yet can be run using a fast quadratic-time dynamic programming idea. Computational performance is essential in high-dimensional domains, such as gene expression data. We describe the approach and discuss on the most important assumptions, building a parallel with assumptions and properties of widely used techniques for the same problem. Experiments using real data from biomedical studies are performed to empirically compare Quor and other methods in a classification task over a selection of high-dimensional data sets

    Thulium and ytterbium-doped titanium oxide thin films deposited by ultrasonic spray pyrolysis

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    Thin films of thulium and ytterbium-doped titanium oxide were grown by metal-organic spray pyrolysis deposition from titanium(IV)oxide bis(acetylacetonate), thulium(III) tris(2,2,6,6-tetramethyl-3,5-heptanedionate) and ytterbium(III) tris(acetylacetonate). Deposition temperatures have been investigated from 300{\deg}C to 600{\deg}C. Films have been studied regarding their crystallity and doping quality. Structural and composition characterisations of TiO2:Tm,Yb were performed by electron microprobe, X-ray diffraction and Fourier transform infrared spectroscopy. The deposition rate can reach 0.8 \mum/h. The anatase phase of TiO2 was obtained after synthesis at 400{\deg}C or higher. Organic contamination at low deposition temperature is eliminated by annealing treatments.Comment: 6 pages, 6 figure

    Análise de modelos de distribuição de freqüências e valores probabilísticos de evapotranspiração potencial para Nova Odessa,SP.

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    The distribution of frequencies of the potential evapotranspiration (ETo) estimated with Priestley-Taylor method was analyzed for the region of Nova Odessa, state of São Paulo, Brazil. The annual maximum values of accumulated ETo were adjusted for periods from 2 to 30 days to the normal, lognormal, gama, beta and gumbel frequency distribution models. Using the Kolmogorov-Smirnov test, it was verified that the distributions normal, lognormal, beta and gumbel presented good adjustment. The gama model did not present adjustment to the data of this study. The medium values of potential evapotranspiração were very close to the obtained at the level of 50% of probability (two years of return period) and lightly inferior to the values of ETo at the level of 75% of probability (four years of return period). Considering the recommendation of adopting the evapotranspiration at the level of 75% of probability, it is verified that a relative underestimation of the irrigations systems design in the region to the if it uses the medium value of ETo in projects

    Coherent states, constraint classes, and area operators in the new spin-foam models

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    Recently, two new spin-foam models have appeared in the literature, both motivated by a desire to modify the Barrett-Crane model in such a way that the imposition of certain second class constraints, called cross-simplicity constraints, are weakened. We refer to these two models as the FKLS model, and the flipped model. Both of these models are based on a reformulation of the cross-simplicity constraints. This paper has two main parts. First, we clarify the structure of the reformulated cross-simplicity constraints and the nature of their quantum imposition in the new models. In particular we show that in the FKLS model, quantum cross-simplicity implies no restriction on states. The deeper reason for this is that, with the symplectic structure relevant for FKLS, the reformulated cross-simplicity constraints, in a certain relevant sense, are now \emph{first class}, and this causes the coherent state method of imposing the constraints, key in the FKLS model, to fail to give any restriction on states. Nevertheless, the cross-simplicity can still be seen as implemented via suppression of intertwiner degrees of freedom in the dynamical propagation. In the second part of the paper, we investigate area spectra in the models. The results of these two investigations will highlight how, in the flipped model, the Hilbert space of states, as well as the spectra of area operators exactly match those of loop quantum gravity, whereas in the FKLS (and Barrett-Crane) models, the boundary Hilbert spaces and area spectra are different.Comment: 21 pages; statements about gamma limits made more precise, and minor phrasing change

    The universal character of Zwanziger's horizon function in Euclidean Yang-Mills theories

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    In light of the recently established BRST invariant formulation of the Gribov-Zwanziger theory, we show that Zwanziger's horizon function displays a universal character. More precisely, the correlation functions of local BRST invariant operators evaluated with the Yang-Mills action supplemented with a BRST invariant version of the Zwanziger's horizon function and quantized in an arbitrary class of covariant, color invariant and renormalizable gauges which reduce to the Landau gauge when all gauge parameters are set to zero, have a unique, gauge parameters independent result, corresponding to that of the Landau gauge when the restriction to the Gribov region Ω\Omega in the latter gauge is imposed. As such, thanks to the BRST invariance, the cut-off at the Gribov region Ω\Omega acquires a gauge independent meaning in the class of the physical correlators.Comment: 14 pages. v2: version accepted by Phys.Lett.

    Choice of parents for dry bean (Phaseolus vulgaris L.) breeding. I. Interactions of mean components by generation and by location.

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    Four dry bean cultivars (Phaseolus vulgaris L.) adapted to the southern region of the state of Minas Gerais, Brazil, were crossed with five exotic cultivars according to a partial diallel design. The nine parents and twenty hybrid population, were tested in six experiment in fully randomized blocks. In one of the experiments, the segregation populations were in the F2 generation. Trials were held at two locations in the state of Minas Gerais and at one location in the state of Goias in 1986. All twenty nine-genetic materials showed heterogeneity concerning grain yield in all trials, with cultivars having a greater effect (additive gene effect) than heterosis (dominance effect), especially in the more advanced generations. No interactions between cultivar x generation effects and cultivar heterosis x generation effects were observed at any location. However, cultivar and cultivar heterosis x locations were significant, suggesting that the choice of segregating populations for genetic improvement of commons beans should be based on the performance of the populations at the locations where they will be used, but disregarding generation. In this way, because of larger quantities of seed, the material can be evaluated in the F4 generation. Despite components of means x location interactions, the population ESAL 501 x A 354 was the most promissing for selection based on grain yield because of the general combining ability of its parents and of grain quality
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