16 research outputs found
Hidden secrets of the Northern Adriatic: "tegnue", peculiar reefs
Research carried out over the last 40 years has underlined the scientific importance of the rocky outcrops scattered on the Northern Adriatic Sea bed sometimes referred to as \u201ctegnue\u201d. The zoobenthic biocenoses developing over these peculiar geological formations are as extraordinary as they
are unique. A study carried out for an entire year in two sampling stations, at different distances from the coast, revealed a very high number of zoobenthic species, including those which have now become rare and are therefore protected in Italian seas. The water turbidity of the northern Adriatic Sea greatly
reduces the quantity of light reaching these outcrops, limiting the activity of autotrophic organisms only to sciaphilous genera. Thus, the most represented trophic categories of zoobenthos are suspension, especially filter feeders. Biodiversity values calculated for the communities of these particular reefs
are far higher than normally found in the soft seabed in nearby areas, but even higher than in other coralligenous outcrops in other marine ecosystem in the world. The ecological role played by the tegnue in the Northern Adriatic is extraordinary because as well as being true oases of biodiversity, they are areas naturally protected against bottom trawl-fishing. Thus, they offer shelter and reproduction sites for a number of fish and invertebrate species, including some under stress due to severe fishing pressure
Biodiversit\ue0\ua0 delle "tegnue" di Chioggia, zona di tutela biologica nel Nord Adriatico
Dose-response curve slope improvement and result reproducibility of ferrous sulphate doped gels analyzed by NMR imaging
Ferrous sulphate gel analysed by relaxation time measurements with NMR imaging is considered a useful dosimeter for 3D determinations of absorbed dose. A protocol for the gel preparation with agarose SeaPlaque that leads to a dosimeter with very high dose sensitivity is described. The dose-response curve slope is about 0.2 s-1 Gy-1 and the G factor turns out to be ~185 ions per 100 eV of absorbed energy. A method for making the measurements and analysing the results that brings about good result reproducibility is suggested. A thorough experimental study of the dependence of the dosimeter response on the elapsed time from preparation to irradiation and from irradiation to NMR measurement has revealed good reproducibility. The above characteristic of the gel system is very interesting, because it shows the possibility of utilizing the dosimeter for absolute dose determinations with satisfactory reliability
A ferrous sulphate gel dosimetry system for NCT studies : response to slow neutron
Neutron capture therapy (NCT) is based on the localised release of energy in tumours from appropriate nuclei bombarded by slow neutrons. It is proposed to measure the spatial dose distribution for some selected nuclei having very large interaction cross sections with neutrons, for different concentrations and concentration gradients, for different geometries and for different neutron beams. To this purpose, it is planned to use a three-dimensional and tissue-equivalent phantom acting as a continuous dosemeter. The dosemeter is a gel solution of ferrous sulphate: the concentration of ferric ions produced by irradiation and correlated to the dose is deduced from the measurement of the proton relaxation times by means of a clinical NMR imaging system. The dosemeter can be used in a mixed field of \u3b3 rays, neutrons and heavy particles. As a first step, the response of the gel system to \u3b3 rays and slow neutrons was measured