Color-coordinate system from a 13th-century account of rainbows.

We present a new analysis of Robert Grosseteste’s account of color in his treatise De iride (On the Rainbow), dating from the early 13th century. The work explores color within the 3D framework set out in Grosseteste’s De colore [see J. Opt. Soc. Am. A 29, A346 (2012)], but now links the axes of variation to observable properties of rainbows. We combine a modern understanding of the physics of rainbows and of human color perception to resolve the linguistic ambiguities of the medieval text and to interpret Grosseteste’s key terms

Anthropogenic fibers and microplastics in the pelagic gooseneck barnacle Lepas (Lepas) anatifera in Capo Milazzo Marine Protected Area (Tyrrhenian Sea): A first characterization

This study provides an assessment of the efficiency of the biofouler Lepas (Lepas) anatifera Linnaeus, 1758 in capturing microplastics and microfiber particles floating in the water column. In this context, we collected pelagic gooseneck barnacles at fixed moorings in the Capo Milazzo Marine Protected Area (MPA). Fibers and fragments were found in the digestive tract of 30% of the 120 specimens collected. The ingested debris were mainly fibers (85.9%) of synthetic (30.6%) and natural (11.7%) origin, with length ranging between 1 and 2 mm (33.3%) and transparent (47.2%). The highest concentration of fibers was recorded in barnacles collected in the western sector of the MPA that is more affected by the input of organic matter coming from several urban wastewaters. No correlation was found between the presence of artificial polymers in L. (Lepas) anatifera and the size of individuals. The great diversity of fibers and plastic fragments by typology, size, shape and color, as well as the large number of bivalve and ostracod shells found in the digestive tract of the samples, confirm the opportunistic diet of these organisms, which can indiscriminately ingest any type of prey and cannot distinguish between microplastics and food. The results obtained, as well as the wide distribution and abundance, and ease of sampling of these barnacle species in macrofouling suggest that including this species in monitoring programs could be a cost-effective and easy method for assessing the presence of microplastics and microfibers in coastal marine waters to monitor the ecological status of pelagic and coastal ecosystems, including MPAs

Summation formulas generated by Hilbert space eigenproblem

We demonstrate that certain classes of Schl\" omilch-like infinite series and series that include generalized hypergeometric functions can be calculated in closed form starting from a simple quantum model of a particle trapped inside an infinite potential well and using principles of quantum mechanics. We provide a general framework based on the Hilbert space eigenproblem that can be applied to different exactly solvable quantum models. Obtaining series from normalization conditions in well-defined quantum problems secures their convergence.Comment: 12 pages, 1 figur

Paraffin waxes in the North-Western Mediterranean Sea: A comprehensive assessment in the Pelagos Sanctuary, a Specially Protected Area of Mediterranean Importance

Paraffin waxes are widely recognized as emerging marine pollutants, even their classification by the recent monitoring programs and the knowledge of their occurrence, and sources of contamination in marine ecosystems are poorly defined and reported. Wax presence and distribution have been evaluated in different environmental compartments in the Pelagos Sanctuary (Mediterranean Sea) floating on the sea surface and stranded on beaches, focussing on their characterization, accumulation areas and pollution inputs. More than 2500 yellow paraffin residues were detected and analysed in the study area showing a prevailing dimension smaller than 5 mm. The Genoa Canyon and the waters facing Gorgona Island resulted in the more polluted areas representing two distinct hotspots of wax accumulation potentially related to the high density of tanker vessels sailing to and from the harbour of Genova and Livorno. Higher concentrations of beached particles were found along the Tuscan coast (11 items/100 m) and on Pianosa Island (110 items/m2). This study gives valuable insights into paraffin wax pollution in the Pelagos Sanctuary, emphasizing the need for harmonized monitoring and detection methods to elucidate the potential impacts on marine organisms. Moreover, mitigating actions are crucial to prevent and curb the waxes pollution of marine ecosystems

A medieval multiverse?: Mathematical modelling of the thirteenth century universe of Robert Grosseteste

In his treatise on light, written about 1225, Robert Grosseteste describes a cosmological model in which the universe is created in a big-bang-like explosion and subsequent condensation. He postulates that the fundamental coupling of light and matter gives rises to the material body of the entire cosmos. Expansion is arrested when matter reaches a minimum density and subsequent emission of light from the outer region leads to compression and rarefaction of the inner bodily mass so as to create nine celestial spheres, with an imperfect residual core. In this paper, we reformulate the Latin description in terms of a modern mathematical model, teasing out consequences implicit in the text, but which the author would not have had the tools to explore. The equations which describe the coupling of light and matter are solved numerically, subjected to initial conditions and critical criteria consistent with the text. Formation of a universe with a non-infinite number of perfected spheres is extremely sensitive to the initial conditions, the intensity of the light and the transparency of these spheres. In this ‘medieval multiverse’, only a small range of opacity and initial density profiles leads to a stable universe with nine perfected spheres. As in current cosmological thinking, the existence of Grosseteste’s universe relies on a very special combination of fundamental parameters

Degradation of plastic materials in the marine environment: A mussel farm as a case study for the development of alternative mussel nets

Currently, mussel farming uses of traditional plastic nets that accumulate on beaches and on the seabed in the event of breakage and accidental dispersion, contributing to the marine litter issue. An attempt is being made to replace the polypropylene nets with alternative materials to make the aquaculture full production cycle more sustainable. However, alternative materials need to be characterised both functionally and environmentally. This article describes a characterisation study in which plastic materials were exposed for approximately three years to the marine environment in a bay dedicated to mussel farming to provide data on the degradation behaviour of the selected polymers for eco-design purposes. Samples of the different materials, in the form of 3-mm thick dumbbells, were placed on the seabed at a depth of 12 m and in the water column at 2 m below the sea surface. At different time periods (after 6, 15, 24, 32 months), the samples were recovered, their mass and thickness were measured, and the mechanical properties were characterised. The results lead to the identification of some materials as sufficiently resistant to deterioration and therefore possible candidates for the application. Other materials generally used to make bags and films showed a very fast degradation and therefore do not seem to meet the performance requirements for mussel farming. The methodology used in this study seems suitable for conducting long-term exposure tests on locations of interest and collecting specific data for eco-design purposes before the application of the product on the markets

Gradients of Variation in the At-Vessel Mortality Rate between Twelve Species of Sharks and Skates Sampled through a Fishery-Independent Trawl Survey in the Asinara Gulf (NW Mediterranean Sea)

Elasmobranchs are priority species for conservation due to their rapid decline determined by the unbalanced struggle between a fragile bio-ecology and strong anthropogenic impacts, such as bycatch from professional fishing. In this context, measuring species resistance to catch of poorly selective gear is of paramount importance. During June-October 2022, five experimental fishing campaigns were carried out in the Asinara Gulf (northern Sardinia) through 35 geographically and bathymetrically representative hauls of an area between 30 and 600 m in depth. Skates prevailed over sharks in the number of species, with seven and five species, respectively. We first evaluated the status of each individual with respect to stress due to the trawl's catch using a three-graded scale. We also recorded individual biometrics (total and disk length, weight and sex, and maturity for males) on board by implementing the best practices in manipulating individuals for physiological recovery and release at sea. After capture, skates resulted in generally better conditions than sharks, although deepwater species of both groups exhibited a worse state than coastal species. The estimated vitality rates also depended on the size of the individuals. This work provides standardized data on the intermingled effect of size, species type, and inhabited depth on the resistance response of some elasmobranch species against capture by trawl fishery activities