187 research outputs found

    La Rendición de Breda de Velázquez y sus fuentes de inspiración en el grabado del siglo XVI

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    This paper aims to analyse the connections between Velázquez 's The Surrender of Breda, also known as The lances, and a series of engravings in wood grain, stranding or fibre, which illustrate a Venetian Bible of 1584.En este trabajo se pretende relacionar la célebre pintura de Diego Velázquez la Rendición de Breda, conocida también como las lanzas, con una serie de entalladuras en madera al hilo, a la hebra o a la fibra, que ilustran una Biblia veneciana de 1584

    Relationship between sandstone composition and provenance. Examples from Palaeozoic sandstones of the Southportuguese Zone

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    Two different types of Upper Paleozoic sandstones from Southportuguese Zone are studied. Data coming from petrographic, sedimentological and regional analyses of the sandstones point to two different anomalies in relation with Dickinson and et al.’s provenance model. Discrimination between modal analysis and petrographic study of arenites is noted, as well as discrimination between source and tectonic setting of the provenance are

    Palynological age constraint of Les Vilelles unit, Catalan Coastal Chain, Spain

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    Les Vilelles unit is a detrital sequence exposed at the southwestern margin of the Catalan Coastal Chain (CCC), NE Spain, below the Carboniferous turbiditic series. Based on the palynological content, the age of this unit was initially assigned to the Middle-Late Devonian (Eifelian to Famennian). Additional radiolarian and conodont findings were considered to be Early–Middle Mississippian (Tournaisian to early Visean). To clarify this age discrepancy a new and more comprehensive palynostratigraphic analysis has been conducted in the upper part of the section representative of Les Vilelles unit. This has provided an assemblage of miospores, acritarchs, prasinophyta phycomata and chitinozoans that can be confidently assigned to a latest Frasnian interval, in contact with the Frasnian–Famennian boundary. Therefore, the present analysis refines the Middle–Late Devonian age formerly assigned, establishes a latest Frasnian age for the top of the unit, and provides new insights to the better understanding of the unconformity and hiatus separating the pre-Carboniferous and Carboniferous CCC series in the Priorat Massif. The study also includes a systematic section with the description of three newly established miospore species: Dibolisporites coniugatum, Dibolisporites prioratum and Rugospora spinosa.This research was funded by the CICYT (Spain) Research Project CGL2011-30011, the Research Group THARSIS RNM 198-PAI (Junta de Andalucía) and the Consolidated Research Group SGR444 (Generalitat de Catalunya

    The influence of puberty on vitamin D status in obese children and the possible relation between vitamin D deficiency and insulin resistance

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    Background: Puberty can affect vitamin D levels. Objectives: The goal of this study was to analyze the relation between vitamin D deficiency and puberty in obese Spanish children, along with the possible interrelation between vitamin D status and degree of insulin resistance. Methods: A cross-sectional study was carried out, in which clinical and biochemical data were gathered from 120 obese and 50 normal weight children between January 2011 and January 2013. Results: Mean vitamin D levels were 19.5 and 31.6 ng/mL in obese pubertal and obese prepubertal children, respectively. About 75% of the obese pubertal subjects and 46% of the obese prepubertal subjects had vitamin D deficiency. Vitamin D levels were significantly lower in pubescent subjects compared with pre-pubescent subjects in summer, fall, and winter. There was no apparent relation between vitamin D levels and homeostasis model assessment index for insulin resistence (expressed in standard deviation score for sex and Tanner stage) in either puberty or pre-puberty. Conclusion: Puberty may be a risk factor for the vitamin D deficiency commonly found in the obese child population. This deficiency is not associated with higher insulin resistance in obese pubertal children compared with obese prepubertal childre

    Facies relationships of Devonian alluvial and coastal deposits of the Furnas Formation, Paraná Basin, Brazil

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    The depositional environment of Upper Silurian-Lower Devonian strata along the eastern margen of the Paraná Basin, Brazil, is reconstructed. Sedimentological analyses are based on a detailed study of two basal sections of the Furnas Formation in Paraná State. Sedimentation was initiated as an alluvial braided system, as evindenced mainly by ridge and bar facies. This evolved into a deltaic complex including mounth bar facies. The alluvial facies grades also laterally into a coastal marine deposits along a sinous shorelin

    Evaluation of mammographic density patterns: reproducibility and concordance among scales

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    <p>Abstract</p> <p>Background</p> <p>Increased mammographic breast density is a moderate risk factor for breast cancer. Different scales have been proposed for classifying mammographic density. This study sought to assess intra-rater agreement for the most widely used scales (Wolfe, Tabár, BI-RADS and Boyd) and compare them in terms of classifying mammograms as high- or low-density.</p> <p>Methods</p> <p>The study covered 3572 mammograms drawn from women included in the DDM-Spain study, carried-out in seven Spanish Autonomous Regions. Each mammogram was read by an expert radiologist and classified using the Wolfe, Tabár, BI-RADS and Boyd scales. In addition, 375 mammograms randomly selected were read a second time to estimate intra-rater agreement for each scale using the kappa statistic. Owing to the ordinal nature of the scales, weighted kappa was computed. The entire set of mammograms (3572) was used to calculate agreement among the different scales in classifying high/low-density patterns, with the kappa statistic being computed on a pair-wise basis. High density was defined as follows: percentage of dense tissue greater than 50% for the Boyd, "heterogeneously dense and extremely dense" categories for the BI-RADS, categories P2 and DY for the Wolfe, and categories IV and V for the Tabár scales.</p> <p>Results</p> <p>There was good agreement between the first and second reading, with weighted kappa values of 0.84 for Wolfe, 0.71 for Tabár, 0.90 for BI-RADS, and 0.92 for Boyd scale. Furthermore, there was substantial agreement among the different scales in classifying high- versus low-density patterns. Agreement was almost perfect between the quantitative scales, Boyd and BI-RADS, and good for those based on the observed pattern, i.e., Tabár and Wolfe (kappa 0.81). Agreement was lower when comparing a pattern-based (Wolfe or Tabár) versus a quantitative-based (BI-RADS or Boyd) scale. Moreover, the Wolfe and Tabár scales classified more mammograms in the high-risk group, 46.61 and 37.32% respectively, while this percentage was lower for the quantitative scales (21.89% for BI-RADS and 21.86% for Boyd).</p> <p>Conclusions</p> <p>Visual scales of mammographic density show a high reproducibility when appropriate training is provided. Their ability to distinguish between high and low risk render them useful for routine use by breast cancer screening programs. Quantitative-based scales are more specific than pattern-based scales in classifying populations in the high-risk group.</p

    Cover contact graphs

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    We study problems that arise in the context of covering certain geometric objects called seeds (e.g., points or disks) by a set of other geometric objects called cover (e.g., a set of disks or homothetic triangles). We insist that the interiors of the seeds and the cover elements are pairwise disjoint, respectively, but they can touch. We call the contact graph of a cover a cover contact graph (CCG). We are interested in three types of tasks, both in the general case and in the special case of seeds on a line: (a) deciding whether a given seed set has a connected CCG, (b) deciding whether a given graph has a realization as a CCG on a given seed set, and (c) bounding the sizes of certain classes of CCG’s. Concerning (a) we give efficient algorithms for the case that seeds are points and show that the problem becomes hard if seeds and covers are disks. Concerning (b) we show that this problem is hard even for point seeds and disk covers (given a fixed correspondence between graph vertices and seeds). Concerning (c) we obtain upper and lower bounds on the number of CCG’s for point seeds
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