1,884 research outputs found

    Characterization of Roman glass tesserae from the Coriglia excavation site (Italy) via energy-dispersive X-ray fluorescence spectrometry and Raman spectroscopy

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    The combined use of handheld energy-dispersive X-ray fluorescence spectrometry, Raman spectroscopy, and micro-energy-dispersive X-ray fluorescence spectrometry permitted the characterization of Roman glass tesserae excavation from the Coriglia (Italy) archeological site. Analyses of ten different glass colors were conducted as spot analyses on intact samples and as both spot analyses and line scans on select cross-sectioned samples. The elemental and molecular information gained from these spectral measurements allowed for the qualitative chemical characterization of the bulk glass, decolorants, opacifiers, and coloring agents. The use of an antimony opacifier in many of the samples supports the late Imperial phasing as determined through numismatic, fresco, ceramics, and architectural evidence. And dealinization of the exterior glass layers caused by the burial environment was confirmed

    Meta-Analysis of Neurobehavioral Outcomes in Very Preterm and/or Very Low Birth Weight Children

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    OBJECTIVE: Sequelae of academic underachievement, behavioral problems, and poor executive function (EF) have been extensively reported for very preterm (≤33 weeks' gestation) and/or very low birth weight (VLBW) (≤1500 g) children. Great variability in the published results, however, hinders the field in studying underlying dysfunctionsanddeveloping intervention strategies. We conductedaquantitative meta-analysis of studies publishedbetween1998and 2008 on academic achievement, behavioral functioning, and EF with the aim of providing aggregated measures of effect size for these outcome domains. METHODS: Suitable for inclusion were 14 studies on academic achievement, 9 studies on behavioral problems, and 12 studies on EF, which compared a total of 4125 very preterm and/or VLBW children with 3197 term-born controls. Combined effect sizes for the 3 outcome domains were calculated in terms of Cohen's d. Q-test statistics were performed to test homogeneity among the obtained effect sizes. Pearson's correlation coefficients were calculated to examine the impact of mean birth weight and mean gestational age, as well as the influence of mean age at assessment on the effect sizes for academic achievement, behavioral problems, and EF. RESULTS: Combined effect sizes show that very preterm and/or VLBW children score 0.60 SD lower on mathematics tests, 0.48 SD on reading tests, and 0.76 SD on spelling tests than term-born peers. Of all behavioral problems stacked, attention problems were most pronounced in very preterm and/or VLBW children, with teacher and parent ratings being 0.43 to 0.59 SD higher than for controls, respectively. Combined effect sizes for parent and teacher ratings of internalizing behavior problems were small ( 0.51). CONCLUSIONS: Very preterm and/or VLBW children have moderate-toseveredeficits inacademicachievement,attentionproblems, andinternalizing behavioral problems and poor EF, which are adverse outcomes that were strongly correlated to their immaturity at birth. During transition to young adulthood these children continue to lag behind term-born peers

    Living in times of war: waste of c. 1600 from two garderobe chutes from the Castle of Middelburg-in-Flanders (Belgium)

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    The material remains and environmental data recovered during a rescue excavation in 2002-03 in the castle of the new town of Middelburg-in-Flanders throw light on the site, region and landscape in wartime. The paper discusses the historical context at the turn of the 16th century, the excavation of the castle, the taphonomy of the chutes, the analysis of the artefacts and ecological data recovered from two garderobe chutes in the upper court, and concludes with a synthesis focussing on the interpretation of the excavated record in the historically attested natural and socio-economic disruption caused by the Spanish-Dutch War

    Scraping the Social? Issues in live social research

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    What makes scraping methodologically interesting for social and cultural research? This paper seeks to contribute to debates about digital social research by exploring how a ‘medium-specific’ technique for online data capture may be rendered analytically productive for social research. As a device that is currently being imported into social research, scraping has the capacity to re-structure social research, and this in at least two ways. Firstly, as a technique that is not native to social research, scraping risks to introduce ‘alien’ methodological assumptions into social research (such as an pre-occupation with freshness). Secondly, to scrape is to risk importing into our inquiry categories that are prevalent in the social practices enabled by the media: scraping makes available already formatted data for social research. Scraped data, and online social data more generally, tend to come with ‘external’ analytics already built-in. This circumstance is often approached as a ‘problem’ with online data capture, but we propose it may be turned into virtue, insofar as data formats that have currency in the areas under scrutiny may serve as a source of social data themselves. Scraping, we propose, makes it possible to render traffic between the object and process of social research analytically productive. It enables a form of ‘real-time’ social research, in which the formats and life cycles of online data may lend structure to the analytic objects and findings of social research. By way of a conclusion, we demonstrate this point in an exercise of online issue profiling, and more particularly, by relying on Twitter to profile the issue of ‘austerity’. Here we distinguish between two forms of real-time research, those dedicated to monitoring live content (which terms are current?) and those concerned with analysing the liveliness of issues (which topics are happening?)

    Effect of High-Fidelity Ice Accretion Simulations on the Performance of a Full-Scale Airfoil Model

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    The simulation of ice accretion on a wing or other surface is often required for aerodynamic evaluation, particularly at small scale or low-Reynolds number. While there are commonly accepted practices for ice simulation, there are no established and validated guidelines. The purpose of this article is to report the results of an experimental study establishing a high-fidelity, full-scale, iced-airfoil aerodynamic performance database. This research was conducted as a part of a larger program with the goal of developing subscale aerodynamic simulation methods for iced airfoils. Airfoil performance testing was carried out at the ONERA F1 pressurized wind tunnel using a 72-in. (1828.8-mm) chord NACA 23012 airfoil over a Reynolds number range of 4.5x10(exp 6) to 16.0 10(exp 6) and a Mach number range of 0.10 to 0.28. The high-fidelity, ice-casting simulations had a significant impact on the aerodynamic performance. A spanwise-ridge ice shape resulted in a maximum lift coefficient of 0.56 compared to the clean value of 1.85 at Re = 15.9x10(exp 6) and M = 0.20. Two roughness and streamwise shapes yielded maximum lift values in the range of 1.09 to 1.28, which was a relatively small variation compared to the differences in the ice geometry. The stalling characteristics of the two roughness and one streamwise ice simulation maintained the abrupt leading-edge stall type of the clean NACA 23012 airfoil, despite the significant decrease in maximum lift. Changes in Reynolds and Mach number over the large range tested had little effect on the iced-airfoil performance

    Swept-Wing Ice Accretion Characterization and Aerodynamics

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    NASA, FAA, ONERA, the University of Illinois and Boeing have embarked on a significant, collaborative research effort to address the technical challenges associated with icing on large-scale, three-dimensional swept wings. The overall goal is to improve the fidelity of experimental and computational simulation methods for swept-wing ice accretion formation and resulting aerodynamic effect. A seven-phase research effort has been designed that incorporates ice-accretion and aerodynamic experiments and computational simulations. As the baseline, full-scale, swept-wing-reference geometry, this research will utilize the 65% scale Common Research Model configuration. Ice-accretion testing will be conducted in the NASA Icing Research Tunnel for three hybrid swept-wing models representing the 20%, 64% and 83% semispan stations of the baseline-reference wing. Three-dimensional measurement techniques are being developed and validated to document the experimental ice-accretion geometries. Artificial ice shapes of varying geometric fidelity will be developed for aerodynamic testing over a large Reynolds number range in the ONERA F1 pressurized wind tunnel and in a smaller-scale atmospheric wind tunnel. Concurrent research will be conducted to explore and further develop the use of computational simulation tools for ice accretion and aerodynamics on swept wings. The combined results of this research effort will result in an improved understanding of the ice formation and aerodynamic effects on swept wings. The purpose of this paper is to describe this research effort in more detail and report on the current results and status to date.
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