442 research outputs found

    Substantial Decrease in Contaminant Concentrations in the Sediments of the Venice (Italy) Canal Network in the Last Two Decades—Implications for Sediment Management

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    The Venice canal network requires periodic intervention to remove sediments that progressively accumulate. The most recent dredging operation was carried out in the second half of the 1990s and early 2000s. These sediments had accumulated over a period of more than 30 years and were highly contaminated with Cd, Cu, Hg, Pb, Zn and PAHs. Sediments deposited after the dredging work were investigated in 2005, 2009, 2014 and 2017 by analysing sediment cores collected from three sites in the canal network. Arsenic, heavy metal and PAH concentrations were observed to be much lower than past values, although Cu, Hg and PAH levels were still relatively high. The high Cu concentrations (mean 161 mg kg−1) are partly due to the widespread use of Cu-based antifouling paint. Current Italian regulations forbid the disposal of dredged sediments with these concentrations inside the lagoon, thereby increasing the cost of canal network maintenance

    Learn to See by Events: Color Frame Synthesis from Event and RGB Cameras

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    Event cameras are biologically-inspired sensors that gather the temporal evolution of the scene. They capture pixel-wise brightness variations and output a corresponding stream of asynchronous events. Despite having multiple advantages with respect to traditional cameras, their use is partially prevented by the limited applicability of traditional data processing and vision algorithms. To this aim, we present a framework which exploits the output stream of event cameras to synthesize RGB frames, relying on an initial or a periodic set of color key-frames and the sequence of intermediate events. Differently from existing work, we propose a deep learning-based frame synthesis method, consisting of an adversarial architecture combined with a recurrent module. Qualitative results and quantitative per-pixel, perceptual, and semantic evaluation on four public datasets confirm the quality of the synthesized images

    Use of compost in urban greening to develop biodiverse herbaceous communities

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    Derelict urban soils are not suitable to grow ornamental traditional vegetation, but they can be effective in becoming areas of biodiversity and nature conservation. The compaction and very low quality of those soils, though do not enable a uniform covering and development of species and plant sizes, necessary to satisfy esthetical requests. Aim of our work was to evaluate the contribution of compost in improving the plant biodiversity and the self-sustainability in the cultivation of an herbaceous community sawn on derelict urban soil. The experimental study was carried out in eight, 2 m2 beds, filled with urban subsoil and sown with a mix of 29 autochthonous herbaceous species: annuals, biennials and perennials. The species selected for the trial are native in the surrounding countryside. We added compost, coming from selected municipal organic waste, in the first 15 cm of soil, then we sow the seed mixture on a thin layer (about 5-10 cm) of seeding substrate. The filling soil was poor in N (0.2 g kg-1) and Corg (4,3 g kg-1) and had alkaline pH (8.3), both this properties can affect negatively the growth of plants, the addition of compost could improve the content of N and Corg and decrease the value of pH. The vegetation was monitored every month since march, number of plants were counted inside a fixed quadrat. The plots with compost showed a more diverse vegetation in terms of species and a longer time of flowering

    Substrates to contrast compaction in urban tree plantings

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    Aim of our work was to assess the ability of recycled crushed bricks employed as a substrate of growth, of contrasting the compaction and improving the development of trees in urban avenues. Soil employed in urban planting is often deep subsoil with a high percentage of fine material (silt and clay) and no organic matter. The excess of soil compaction due to trampling and car parking can seriously affect the survival of trees in these conditions. Coarse recycled materials already used in urban green areas, allow a better air circulation and water drainage in the rizosphere and can be a valid solution to reduce the post transplant crisis. The materials employed as substrate were: compost, soil, crushed bricks 0-30 mm, crushed bricks 6-30 mm The experimental trial was set up planting 36 lindens in 1) soil, 2)soil +15% compost; 3) crushed bricks 0-30 mm; 4) crushed bricks 0-30 mm + 15% compost; 5) crushed bricks 6-30 mm; 6) crushed bricks 6-30 mm + 15% compost. The monitoring included: sprouts length, number of sprouts, SPAD chlorophyll, and dynamic plate resistance. The preliminary results showed that the crushed bricks showed the highest resistance to compaction and the combination of crushed bricks 0-30 mm + compost developed the average longest sprouts. At this stage of the research the best compromise between resistance to compaction and growth seemd to be crushed bricks 6-30 mm + compost

    Modeling the thermal response of the retina during Indocyanine Green-assisted peeling of the internal limiting membrane

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    Previous works and surgical practices had shown that Indocyanine Green (ICG)-assisted peeling of the internal limiting membrane (ILM) in macular hole surgery may cause retinal damage. Different hypothesis were proposed in order to explain the induced damage. In this study the possibility of heat damage to the retina is investigated.

    Analysis of second harmonic generation polarization profiles: an attempt to devise a complete three-dimensional model

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    We report the first attempt to build a three dimensional model of the polarization modulated second harmonic generation and emission dynamics from collagen fibrils under realistic conditions. Our analytical model is constructed by integration of previous knowledge on the stimulation of a second harmonic polarization in a non-centrosymmetric cylindrical target, and on the propagation of a resultant second harmonic disturbance. The application of our paradigm to actual biological targets allows one to retrieve their spatial orientation, mutual organization and inner configuration, which holds great potential to develop biological investigations and theragnostic applications

    Saldatura laser della pelle: stato dell’arte e prospettive future

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    Da diversi anni ormai la tecnologia laser svolge un ruolo importante nell’ambito di numerose applicazioni biomedicali. Il principale vantaggio prospettato dalle tecniche laser è quello di ridurre notevolmente il trauma chirurgico riducendo il tempo di guarigione e il rischio di complicazioni post-operatorie con netto miglioramento della qualità della vita dei pazienti. Una tra le applicazioni più promettenti del laser in campo medico-chirurgico è la saldatura dei tessuti biologici (“laser tissue welding”). La giunzione di lembi di tessuto tramite luce laser è stata conseguita per la prima volta con successo alla fine degli anni settanta, impiegando un laser a neodimio:ittrio-alluminio-garnet (Nd:YAG) per l’anastomosi microvascolare della carotide e delle arterie femorali di topo. Successivamente, la saldatura laser-assistita è stata sperimentata su numerosi modelli come vasi sanguiferi, pelle, cornea, nervi, intestino, tendini, tratto urinario, tessuto biliare e così via [1, 2]. Tale tecnica, grazie alle sue caratteristiche minimamente invasive, ha assunto progressivamente rilevanza a livello clinico dove appare oggi come valida alternativa all’approccio chirurgico tradizionale. Attualmente sono sempre più numerose le applicazioni di saldatura laser che stanno ricevendo il consenso della comunità scientifica

    Notes on the mechanism of low-temperature laser tissue welding

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    In this report we propose an hypothesis on the mechanism of low-temperature laser welding of a model connective tissue (cornea), based on the reorganization of the proteoglycans of the extracellular matrix
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