106 research outputs found
On the use of SRTM and altimetry data for flood modeling in data-sparse regions
No full textThe growing availability of remotely sensed data has fostered the implementation of hydraulic modeling in poorly gauged regions. However, these applications suffer the lack of knowledge of river bathymetry, which cannot be directly inferred from satellite instruments. This study explores the possibility to set up, calibrate, and validate a hydrodynamic model which geometry is based on global and freely available satellite data. First, the study tests two different procedures for inferring the river bathymetry under the water surface level. Second, focusing on a Po River stretch of ∼140 km (Northern Italy), the study further assesses the suitability of spaceborne topographic and remotely sensed altimetry data (i.e.; ERS-2 and ENVISAT) for implementing and calibrating hydrodynamic models. Referring to 90 m SRTM (Shuttle Radar Topography Mission) digital elevation model for the representation of the riverbed morphology, the work analyzes the performances of different 1-D numerical models which cross sections are modified according to two approaches: (1) Channel Bankfull depth (CB) and (2) Slope-Break (SB) approach. The calibration and validation processes are performed by referring to extended altimetry time series (∼16 years of data), while the accuracy and trustworthiness of 1-D models are tested with reference to a quasi-2-D model based on detailed geometry data. Results show that both CB and SB approaches enhance the performance of SRTM-based models. In particular, the SB approach is completely based on satelliteborne data and shows Nash-Sutcliffe efficiency, MAE, and RMSE values similar to those obtained with the benchmark model
Crystal-chemistry and cation ordering in the system Diopside-Jadeite: a detailed study by crystal structure refinement
No full textLaboratory experiments for analysing the impact of herbaceous vegetation on riverbank erosion
No full textComparison of chemical analyses of sodic pyroxenes by X-ray structure refinement and electron microprobe techniques.
No full textWill there be a second extinction? Molecular identification of multiple alien water frogs (pelophylax ridibundus sensu lato) in tuscany, central Italy, reveals genetic pollution within a unique hybridogenetic system
No full textThe introduction of alien water frogs is perhaps one of the most underestimated herpetological conservation issues in Europe. The identification of distinct species is highly challenging at the phenotypic level, and artificial syntopy between various taxa and lineages may lead to diverse outcomes, including hybridisation and local extinction. In central Italy the native synklepton of Pelophylax bergeri (the parental taxon) and P. kl. (klepton) hispanicus (the hybridogenetic hybrid, which clonally transmits the genome of an extinct ridibundus-like taxon) is present. Until recently, data regarding the presence of alien water frogs in central Italy was scarce, and no alien taxa have been reported for Tuscany. In this study, four distinct non-native Pelophylax lineages have been identified via molecular analysis in the Cecina and Arno river basins and ascribed to the Marsh frog group (P. ridibundus sensu lato). Alien Pelophylax ridibundus, P. kurtmuelleri, and P. cf. bedriagae sensu stricto currently appear to be widespread in the Cecina basin. Furthermore, evidence of hybridisation with autochthonous taxa has been suggested by genetic analyses in four out of eight sampling localities. With a view to evaluate urgent conservation strategies, a greater sampling effort is required to assess the actual distribution and ecology of the alien lineages, and further research is necessary to measure their impact on the native hybridogenetic system of the central-southern Italian pool frogs
A Rendering Engine for Integral Imaging in Augmented Reality Guided Surgery
No full textIn the field of image-guided surgery, Augmented Reality wearable displays are a widely studied and documented technology for their ability to provide egocentric vision together with the overlap between real and virtual content. In particular, optical see-through (OST) displays have the advantage of maintaining visual perception of the real world. However, OST displays suffer from vergeance-accomodation conflict when virtual content is superimposed on real world. Furthermore, the calibration methods required to achieve geometric consistency between real and virtual are inherently error-prone. One of the solutions, already studied, to these problems is to use of integral imaging displays. In this paper we present an easy and straightforward real-time rendering strategy implemented in modern OpenGL to show the 3D image of a virtual object on a wearable OST display deploying the integral imaging approach. Clinical Relevance- The algorithm proposed open the way towards more effective AR surgical navigation in terms of comfort of the AR experience and accuracy of the AR guidance
Discovery of alien water frogs (gen. Pelophylax) in Umbria, with first report of P. shqipericus in Italy
No full textZamenis lineatus (Camerano, 1891) (Saettone occhirossi), Z. longissimus (Laurenti, 1768) (Saettone comune).
No full textCation ordering of orthopyroxenes from the Skaergaard Intrusion: implications for the subsolidus cooling rates and permeabilities
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