Search results for "LIGHT"
showing 10 items of 3575 documents
Phytoplankton assemblages in twenty-one Sicilian reservoirs: relationships between species composition and environmental factors
2000
Data collected in a limnological survey, carried out between 1987 and 1988 on 21 Sicilian reservoirs of varying trophic state, were ordinated using CANOCO 3.1 to generalise the way in which the structure of phytoplankton assemblage is conditioned by both physical and chemical variables. The results showed that in these man-made lakes, characterised by conspicuouswater-level fluctuations, the annual and interannual variability in the abundance and composition of phytoplankton may be strongly influenced by their peculiar hydraulic regimes rather than by nutrient availability. In particular, it was highlighted that, from the early summer, water abstraction often leads to increased circulation …
Limited potential for bird migration to disperse plants to cooler latitudes
2021
Climate change is forcing the redistribution of life on Earth at an unprecedented velocity1,2. Migratory birds are thought to help plants to track climate change through long-distance seed dispersal3,4. However, seeds may be consistently dispersed towards cooler or warmer latitudes depending on whether the fruiting period of a plant species coincides with northward or southward migrations. Here we assess the potential of plant communities to keep pace with climate change through long-distance seed dispersal by migratory birds. To do so, we combine phenological and migration information with data on 949 seed-dispersal interactions between 46 bird and 81 plant species from 13 woodland communi…
Space medicine: use of ex vivo human respiratory mucosa in the survey of the effects of microgravity on the respiratory system
2019
In the near future, the length and scope of space travel is set to increase significantly. The number of individuals who will have access to extra-terrestrial travels is also increasing. In view of the growing international interest towards manned long-term space exploration, possible effects of exposure to microgravity conditions affecting the respiratory system are subject of interest by major space agencies (NASA and ESA primarily). Our team has developed an advanced 3d tissue model of the human bronchial mucosa within a wide research project involving several universities and space agencies at international level. The model will be used to study the structural/functional alterations of …
Sunlight-induced functionalisation reactions of heteroaromatic bases with aldehydes in the presence of TiO2: A hypothesis on the mechanism
2007
In previous studies we reported a new photocatalytic system involving polycrystalline TiO2 for the selective functionalisation of heteroaromatic bases with ethers and amides. In order to extend the applications of this new reaction and to better understand the mechanism involved, we have examined aromatic and aliphatic aldehydes as acyl radical sources for the nucleophilic addition to protonated N-heteroarenes in acetonitrile as the solvent and TiO2/H2O2 as the photocatalytic system. Acyl radicals may undergo decarbonylation to yield the corresponding alkyl radicals. Acyl/alkyl derivative ratios depend on the nature of the aldehydes, and present a different distribution from that obtained i…
Sunlight-induced reactions of some heterocyclic bases with ethers in the presence of TiO2. A green route for the synthesis of heterocyclic aldehydes
2005
Efficient H2 production by photocatalytic water splitting under visible light over modified TiO2-based catalysts
2018
Efficient H2 production by photocatalytic water splitting under visible light over modified TiO2-based catalysts
Static Light Scattering as a tool to control extruded liposomes concentration: A novel physicist-friendly approach
Population trapping due to cavity losses
2008
In population trapping the occupation of a decaying quantum level keeps a constant non-zero value. We show that an atom-cavity system interacting with an environment characterized by a non-flat spectrum, in the non-Markovian limit, exhibits such a behavior, effectively realizing the preservation of nonclassical states against dissipation. Our results allow to understand the role of cavity losses in hybrid solid state systems and pave the way to the proper description of leakage in the recently developed cavity quantum electrodynamic systems.
Marble and stone revetment and pavements: Context and provenance
2022
Earlier excavations and survey at Vagnari furnished hardly any evidence for the use of marble at the site, and so the vicus was considered to be a low status settlement, with only a few rooms having been elegant enough to decorate them with marble floors or revetment. The fragments recovered were not analysed scientifically to determine the location of the quarries from which the marbles came. Of particular interest, however, were two small fragments of inscriptions on white marble retrieved from the rubble fill dumped in the 4th century AD in the reservoir. These originally may have been attached, when intact, to votive or funerary monuments, suggesting that the occasional commemorative mo…