190 research outputs found

    The Virtual Reconstruction of the Aesculapius and Hygeia Statues from the Sanctuary of Isis in Lilybaeum: Methods and Tools for Ancient Sculptures’ Enhancement

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    Thanks to recent technological developments in 3D surveys, computer graphics and virtual reality, new scenarios have been opened for the documentation and enhancement of ancient sculptures. When not totally preserved, sculptures can be digitally reproduced, modified and visualized to simulate their physical or virtual reconstruction in a non-invasive way for specialists or for dissemination aims. The virtual sculptural reconstruction process starts usually from the 3D survey of real fragments, and then continues by integrating missing parts with 3D modelling techniques by means of source evaluation. Along with primary data sources (reality-based model), secondary data sources (photos, drawings and 3D models of similar sculptures) can be directly used in the reconstruction process. This approach has a double advantage of making the reconstruction activities easier and less arbitrary, contributing to a decrease in the degree of uncertainty for the sculptural reconstruction work, also thanks to many iconographic comparisons to ancient copies. Moreover, virtual reconstruction can be easily visualized alongside a scalable rendering system using open-source Web3D apps and platforms, accessing information, 3D models and descriptions in order to enhance the experience of artworks. Inspecting theoretical and technical approaches, this work aims at establishing how primary and secondary data sources can be effectively used in sculptural reconstruction workflows, and how 3D outputs can be applied to implement digital sculptural heritage exploitation for museums and cultural institutions. The statues of Aesculapius and Hygeia from the sanctuary of Isis in Lilybaeum (Marsala, Italy) were chosen as a case study

    DNA-Barcoding to solve the tricky case of co-occuring Sabellaria (ANNELIDA) species in the Mediterranean Sea

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    Intraspecific morphological variation of key taxonomic features is probably responsible for frequent misidentification of Sabellaria (Lamarck, 1818) species. This is the case of Sabellaria alcocki Gravier, 1906 whose Mediterranean records probably refer to juveniles of S. spinulosa (Leuckart, 1849). We hereby provide molecular tools (DNA barcoding) to improve correct delimitation of the Mediterranean species of this genus

    Prevalence, correlates, and prognosis of peripheral artery disease in rural ecuador-rationale, protocol, and phase I results of a population-based survey: an atahualpa project-ancillary study

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    Background. Little is known on the prevalence of peripheral artery disease (PAD) in developing countries. Study design. Population-based study in Atahualpa. In Phase I, the Edinburgh claudication questionnaire (ECQ) was used for detection of suspected symptomatic PAD; persons with a negative ECQ but a pulse pressure ≥65 mmHg were suspected of asymptomatic PAD. In Phase II, the ankle-brachial index will be used to test reliability of screening instruments and to determine PAD prevalence. In Phase III, participants will be followed up to estimate the relevance of PAD as a predictor of vascular outcomes. Results. During Phase I, 665 Atahualpa residents aged ≥40 years were enrolled (mean age: 59.5 ± 12.6 years, 58% women). A poor cardiovascular health status was noticed in 464 (70%) persons of which 27 (4%) had a stroke and 14 (2%) had ischemic heart disease. Forty-four subjects (7%) had suspected symptomatic PAD and 170 (26%) had suspected asymptomatic PAD. Individuals with suspected PAD were older, more often women, and had a worse cardiovascular profile than those with nonsuspected PAD. Conclusions. Prevalence of suspected PAD in this underserved population is high. Subsequent phases of this study will determine whether prompt detection of PAD is useful to reduce the incidence of catastrophic vascular diseases in the region

    The Stock Genetic Structure of Two Sparidae Species, Diplodus vulgaris and Lithognathus mormyrus, in the Mediterranean Sea.

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    Polyacrilamide gel electrophoresis (PAGE) of allozymes was used to investigate the intraspecies genetic variation and the genetic stock structure of Diplodus vulgaris and Lithognathus mormyrus captured from eight localities in the Mediterranean Sea. Twenty-two and 20 putative enzyme-coding loci were examined, respectively, in D. vulgaris and L. mormyrus. Polymorphic loci at the 95% level were used to assess the allozyme variability in D. vulgaris (AAT-2, EST-1, GLDH, PEPB-2, PGI-2, PGM, SDH) and L. mormyrus (AAT-2, EST-1, GLDH, MDH-2, PGI-2, PGM). The proportion of polymorphic loci in both species ranged from 0.31 (D. vulgaris) to 0.30 (L. mormyrus), and the observed and expected mean heterozygosity varied between 0.082 and 0.093 (D. vulgaris) and between 0.069 and 0.072 (L. mormyrus). The mean value of observed heterozygosity in D. vulgaris showed a deficit of heterozygosites, thereby indicating a Wahlund effect in the samples examined. Significant genetic differentiation (mean value of θ = 0.013, p < 0.005) was found in D. vulgaris indicating an intraspecific genetic substructure among the samples examined, whereas the mean value of θ = 0.001, p > 0.05 found in L. mormyrus showed a high degree of genetic homogeneity. The results showed the presence of distinct subpopulations of D. vulgaris among the sampled sites, and suggested that analysis of allozymes may provide important information on the genetic stock structure of these two sparids to ensure sustainable management of these species

    SURVEY AND VIRTUAL RECONSTRUCTION OF ANCIENT ROMAN FLOORS IN AN ARCHAEOLOGICAL CONTEXT

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    Despite the consistent development of approaches aimed at the virtual reconstruction of whole houses or archaeological monuments, the variety of technologies involved in virtual reconstruction procedures and the complexity of a rigorous process to provide validation models, seems to limit a univocal and shared standards adoption. For example, compared to the large number of contributions on the virtual reconstruction of whole architectures or cultural heritage sites, only a few works have proposed a rigorous workflow specific to mosaics and ancient floors and to their virtual reconstruction. The goal of this work is to present the first results on the virtual reconstruction of the "Temple of Isis" in Marsala (Italy); in particular, the work is aimed at the virtual reconstruction of the mosaic and the opus spicatum floor still preserved in situ. A close-range photogrammetric survey was carried out in order to provide a detailed floors 3D reconstruction; a structure-from-motion photogrammetry approach was employed to obtain a detailed 2D and 3D documentation with millimetric accuracy and high level of colour fidelity. Thanks to the photogrammetric products, accurate virtual restoration/reconstruction of the whole floor surfaces was conducted in a rigorous way and as close as possible to the historical reality

    Impatto di Caulerpa Taxifolia var. Distichophylla su macro- e meiofauna associate a Posidonia oceanica

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    Macro- and meiofauna associated with Posidonia oceanica meadows colonized by the invasive alga Caulerpa taxifolia var. distichophylla (Caulerpales) in southern Sicily were analyzed and compared with assemblages of control meadows from the same area. Independently from the degree of invasion (severe or partial), the affected macrofaunal assemblages significantly differed from the controls with the former ones characterized by an increase of molluscs and polychaetes and the decrease of crustaceans. Meiofaunal assemblages showed contrasting results being affected by severe algal invasion but not significantly differing from control assemblages under partial invasion conditions, suggesting some tolerance to the invader

    Influence of Bed Roughness on Flow and Turbulence Structure Around a Partially-Buried, Isolated Freshwater Mussel

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    The present study uses eddy-resolving numerical simulations to investigate how bed roughness affects flow and turbulence structure around an isolated, partially-buried mussel (Unio elongatulus) aligned with the incoming flow. The rough-bed simulations resolve the flow past the exposed part of a gravel bed, whose surface is obtained from a laboratory experiment that also provides some additional data for validation of the numerical model. Results are also discussed for the limiting case of a horizontal smooth bed. Additionally, the effects of varying the level of burial of the mussel inside the substrate and the discharge through the two mussel siphons are investigated via a set of simulations in which the ratio between the median diameter of the (gravel) particles forming the rough bed, d50, and the height of the exposed part of the mussel, h, varies between 0.10 and 0.22. The increase of the bed roughness is associated with a strong amplification of the turbulence kinetic energy in the near-wake region. Increasing the bed roughness and/or reducing h intensifies the interactions of the eddies generated by the bed particles with the base and tip vortices induced by the active filtering and by the mussel shell, respectively, which, in turn, induces a more rapid dissipation of these vortices. Increasing the bed roughness also reduces the strength of the main downwelling flow region forming in the wake. The strong downwelling near the symmetry plane is the main reason why the symmetric wake shedding mode dominates in the smooth bed simulations with negligible active filtering. By contrast, the anti-symmetric wake shedding mode dominates in the simulations conduced with a high value of the bed roughness. The mean streamwise drag force coefficient for the emerged part of the shell and the dilution of the excurrent siphon jet increase with increasing bed roughness

    Marine alien species in Italy: A contribution to the implementation of descriptor D2 of the Marine Strategy Framework Directive

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    A re-examination of marine alien species or Non Indigenous Species (NIS) reported in Italian Seas, until December 2018, is provided, focusing on establishment success, year of first record, origin, potential invasiveness, and likely pathways, in particular. Furthermore, their distribution is assessed according to the marine subregions outlined by the European Union (EU) Marine Strategy Framework Directive: Adriatic Sea (ADRIA), Ionian Sea and Central Mediterranean Sea (CMED), and Western Mediterranean Sea (WMED). In Italy, 265 NIS have been detected with the highest number of species being recorded in the CMED (154 species) and the WMED (151 species) subregions, followed by the ADRIA (143) subregion. Most of these species were recorded in more than one subregion. One hundred and eighty (180 or 68%) NIS have established stable populations in Italian Seas among which 26 have exhibited invasive traits. As regards the taxa involved, Macrophyta rank first with 65 taxa. Fifty-five of them are established in at least one subregion, mostly in the ADRIA and the CMED. Crustacea rank second with 48 taxa, followed by Polychaeta with 43 taxa, Mollusca with 29 taxa, and Fishes with 28 taxa, which were mainly reported from the CMED. In the period 2012-2017, 44 new alien species were recorded, resulting in approximately one new entry every two months. Approximately half of the NIS (~52%) recorded in Italy have most likely arrived through the transport-stowaway pathway related to shipping traffic (~28% as biofoulers, ~22% in ballast waters, and ~2% as hitchhikers). The second most common pathway is the unaided movement with currents (~19%), followed by the transport-contaminant on farmed shellfishes pathway (~18%). "Unaided" is the most common pathway for alien Fishes, especially in the CMED; escapes from confinement account for ~3% and release in nature for ~2%. The present NIS distribution hotspots for new introductions were defined at the first recipient area/location in Italy. In the ADRIA, the hotspot, Venice, accounts for the highest number of alien taxa introduced in Italy, with 50 newly recorded taxa. In the CMED subregion, the hotspots of introduction are the Taranto and Catania Gulfs, hosting 21 first records each. The Strait of Sicily represents a crossroad between alien taxa from the Atlantic Ocean and the Indo-Pacific area. In the WMED, bioinvasion hotspots include the Gulfs of Naples, Genoa and Livorno. This review can serve as an updated baseline for future coordination and harmonization of monitoring initiatives under international, EU and regional policies, for the compilation of new data from established monitoring programs, and for rapid assessment surveys

    Assessment of the Sabellaria alveolata reefs’ structural features along the Southern coast of Sicily (Strait of Sicily, Mediterranean Sea)

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    The honeycomb worm Sabellaria alveolata is a gregarious tube-dwelling polychaete that builds remarkable biogenic reefs in marine coastal waters. Sabellaria alveolata reefs are considered valuable marine habitats requiring protection measures for their conservation, as they play a key role in the functioning of coastal ecosystems. Sabellarid reefs are extensively developed along the Atlantic coasts of Europe and reported for the Mediterranean Sea and the Italian coasts, where large reefs have been recorded in several localities. Fragmentary information is available on their health status, Sabellaria reefs thus being listed as “Data Deficient” in the Red List of Marine Habitats. To fill this knowledge gap, this study focused on the analysis of the structure of three reefs found along the southern coast of Sicily. In particular, we aimed to assess their phases with respect to the natural cycle that characterizes the sabellarid reefs. Reef features were analyzed both on the macroscale, based on the bioconstruction size (diameter and thickness) and degree of fragmentation, and on the microscale, based on the measurement of worm density, opercular length and sand porch presence. This study reveals relevant differences among reefs of the studied locations. These differences we attribute to the temporal shift linked to the natural reef phases, albeit further analyses are needed to understand the possible effect of natural and anthropogenic sources of variation on the Southern Sicilian reefs. In conclusion, Sabellaria reefs are a unique and persistent habitat along the Sicilian coast requiring proper management and conservation measures

    Evaluation of the Purity of Magnesium Hydroxide Recovered from Saltwork Bitterns

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    Magnesium has been listed among the 30 critical raw materials by the European Union. In recent years, many green and sustainable alternative Mg2+ sources have been sought to satisfy the EU’s demand and to avoid mineral ore consumption. In this context, saltwork bitterns, the by-products of solar sea salt production, have attracted much attention thanks to their high Mg2+ concentrations (up to 80 g/L) and low Ca2+ and bicarbonate contents (&lt;0.5 g/L). Although investigations on Mg2+ extraction from bitterns in the form of Mg(OH)2(s) have already been performed, product purity has never been properly addressed. Mg(OH)2(s) is a chemical compound of great interest and extensive utility in numerous industrial applications only if the powder’s purity is &gt;95% (w/w). This work presents a comprehensive experimental effort of reactive precipitation tests with NaOH solutions at stoichiometric and over-stoichiometric concentrations to: (i) assess the technical feasibility of Mg2+ recovery from real bitterns collected in saltworks of the Trapani district (Italy) and, (ii) for the first time, conduct an extensive purity investigation of the precipitated magnesium hydroxide powders as brucite. This experimental investigation demonstrates the possibility of extracting highly valuable compounds from saltwork bittern waste, embracing the water valorization and resource recovery approach
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