357 research outputs found

    A Geometric Feature-Based Algorithm for the Virtual Reading of Closed Historical Manuscripts

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    X-ray Computed Tomography (CT), a commonly used technique in a wide variety of research fields, nowadays represents a unique and powerful procedure to discover, reveal and preserve a fundamental part of our patrimony: ancient handwritten documents. For modern and well-preserved ones, traditional document scanning systems are suitable for their correct digitization, and, consequently, for their preservation; however, the digitization of ancient, fragile and damaged manuscripts is still a formidable challenge for conservators. The X-ray tomographic approach has already proven its effectiveness in data acquisition, but the algorithmic steps from tomographic images to real page-by-page extraction and reading are still a difficult undertaking. In this work, we propose a new procedure for the segmentation of single pages from the 3D tomographic data of closed historical manuscripts, based on geometric features and flood fill methods. The achieved results prove the capability of the methodology in segmenting the different pages recorded starting from the whole CT acquired volume

    Seismic modeling using the frozen Gaussian approximation

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    We adopt the frozen Gaussian approximation (FGA) for modeling seismic waves. The method belongs to the category of ray-based beam methods. It decomposes seismic wavefield into a set of Gaussian functions and propagates these Gaussian functions along appropriate ray paths. As opposed to the classic Gaussian-beam method, FGA keeps the Gaussians frozen (at a fixed width) during the propagation process and adjusts their amplitudes to produce an accurate approximation after summation. We perform the initial decomposition of seismic data using a fast version of the Fourier-Bros-Iagolnitzer (FBI) transform and propagate the frozen Gaussian beams numerically using ray tracing. A test using a smoothed Marmousi model confirms the validity of FGA for accurate modeling of seismic wavefields.Comment: 5 pages, 8 figure

    Denitrification and inference of nitrogen sources in the karstic Floridan Aquifer

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    Aquifer denitrification is among the most poorly constrained fluxes in global and regional nitrogen budgets. The few direct measurements of denitrification in groundwaters provide limited information about its spatial and temporal variability, particularly at the scale of whole aquifers. Uncertainty in estimates of denitrification may also lead to underestimates of its effect on isotopic signatures of inorganic N, and thereby confound the inference of N source from these data. In this study, our objectives are to quantify the magnitude and variability of denitrification in the Upper Floridan Aquifer (UFA) and evaluate its effect on N isotopic signatures at the regional scale. Using dual noble gas tracers (Ne, Ar) to generate physical predictions of N<sub>2</sub> gas concentrations for 112 observations from 61 UFA springs, we show that excess (i.e. denitrification-derived) N<sub>2</sub> is highly variable in space and inversely correlated with dissolved oxygen (O<sub>2</sub>). Negative relationships between O<sub>2</sub> and δ<sup>15</sup>N<sub>NO3</sub> across a larger dataset of 113 springs, well-constrained isotopic fractionation coefficients, and strong <sup>15</sup>N:<sup>18</sup>O covariation further support inferences of denitrification in this uniquely organic-matter-poor system. Despite relatively low average rates, denitrification accounted for 32 % of estimated aquifer N inputs across all sampled UFA springs. Back-calculations of source δ<sup>15</sup>N<sub>NO3</sub> based on denitrification progression suggest that isotopically-enriched nitrate (NO<sub>3</sub><sup>–</sup>) in many springs of the UFA reflects groundwater denitrification rather than urban- or animal-derived inputs

    X‐ray Tomography Unveils the Construction Technique of Un‐Montu’s Egyptian Coffin (Early 26th Dynasty)

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    The Bologna Archaeological Museum, in cooperation with prestigious Italian universities, institutions, and independent scholars, recently began a vast investigation programme on a group of Egyptian coffins of Theban provenance dating to the first millennium BC, primarily the 25th–26th Dynasty (c. 746–525 BC). Herein, we present the results of the multidisciplinary investigation car-ried out on one of these coffins before its restoration intervention: the anthropoid wooden coffin of Un‐Montu (Inv. MCABo EG1960). The integration of radiocarbon dating, wood species identifica-tion, and CT imaging enabled a deep understanding of the coffin’s wooden structure. In particular, we discuss the results of the tomographic investigation performed in situ. The use of a transportable X‐ray facility largely reduced the risks associated with the transfer of the large object (1.80 cm tall) out of the museum without compromising image quality. Thanks to the 3D tomographic imaging, the coffin revealed the secrets of its construction technique, from the rational use of wood to the employment of canvas (incamottatura), from the use of dowels to the assembly procedure

    Coupled genomic evolutionary histories as signatures of organismal innovations in cephalopods: co-evolutionary signatures across levels of genome organization may shed light on functional linkage and origin of cephalopod novelties

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    © The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Ritschard, E. A., Whitelaw, B., Albertin, C. B., Cooke, I. R., Strugnell, J. M., & Simakov, O. Coupled genomic evolutionary histories as signatures of organismal innovations in cephalopods: co-evolutionary signatures across levels of genome organization may shed light on functional linkage and origin of cephalopod novelties. BioEssays, 41, (2019): 1900073, doi: 10.1002/bies.201900073.How genomic innovation translates into organismal organization remains largely unanswered. Possessing the largest invertebrate nervous system, in conjunction with many species‐specific organs, coleoid cephalopods (octopuses, squids, cuttlefishes) provide exciting model systems to investigate how organismal novelties evolve. However, dissecting these processes requires novel approaches that enable deeper interrogation of genome evolution. Here, the existence of specific sets of genomic co‐evolutionary signatures between expanded gene families, genome reorganization, and novel genes is posited. It is reasoned that their co‐evolution has contributed to the complex organization of cephalopod nervous systems and the emergence of ecologically unique organs. In the course of reviewing this field, how the first cephalopod genomic studies have begun to shed light on the molecular underpinnings of morphological novelty is illustrated and their impact on directing future research is described. It is argued that the application and evolutionary profiling of evolutionary signatures from these studies will help identify and dissect the organismal principles of cephalopod innovations. By providing specific examples, the implications of this approach both within and beyond cephalopod biology are discussed.E.A.R. and O.S. are supported by the Austrian Science Fund (Grant No. P30686‐B29). E.A.R. is supported by Stazione Zoologica Anton Dohrn (Naples, Italy) PhD Program. The authors wish to thank Graziano Fiorito (SZN, Italy), Hannah Schmidbaur (University of Vienna, Austria), Thomas Hummel (University of Vienna, Austria) for many insightful comments and reading of the draft manuscript. The authors would like to apologize to all colleagues whose work has been omitted due to space constraints

    Azo Complexes of Osmium(II): Preparation and Reactivity of Organic Azide and Hydrazine Derivatives

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    From closed testaments to books: Virtual X-ray Reading as an alternate digitization technology for fragile documents

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    In recent years, research and technology made considerable progress in increasing the speed and the safety of the entire digtization process of ancient collections. Despite this, imaging ancient, fragile or un-opened documents remains a formidable challenge. We employ an alternate digitization technique for hand-written documents, exploiting x-ray tomography: Virtual X-ray Reading. Thanks to the high penetration of x-rays, we can acquire 3-dimensional (3D) tomographic images of a multi-page document without opening it. The x-ray contrast necessary for the readability is produced by the chemical composition and the consequent strong x-ray absorption of the iron gall inks - largely used for European handwritten documents. We present the development of this technology, from the chemical investigations of the inks to the tomography of an unopened Venetian testament and of an 18th century, 200-page, handwritten book
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