All-Optical Reconfiguration of Ultrafast Dichroism in Gold Metasurfaces

Optical metasurfaces have come into the spotlight as a promising platform for light manipulation at the nanoscale, including ultrafast all-optical control via excitation with femtosecond laser pulses. Recently, dichroic metasurfaces have been exploited to modulate the polarization state of light with unprecedented speed. This work theoretically predicts and experimentally demonstrates by pump–probe spectroscopy the capability to reconfigure the ultrafast dichroic signal of a gold metasurface by simply acting on the polarization of the pump pulse, which is shown to reshape the spatio-temporal distribution of the optical perturbation. The photoinduced anisotropic response, driven by out-of-equilibrium carriers and extinguished in a sub-picosecond temporal window, is readily controlled in intensity by tuning the polarization direction of the excitation up to a full sign reversal. Hence, nonlinear metasurfaces are here demonstrated to offer the flexibility to tailor their ultrafast optical response in a fully all-optically reconfigurable platform

Facies created by the yellow coral Dendrophyllia cornigera (Lamarck, 1816): Origin, substrate preferences and habitat complexity

The yellow coral Dendrophyllia cornigera (Lamarck, 1816) is a NE Atlantic-Mediterranean scleractinian. It is considered a typical hard bottom species, generally reported on outcropping rocks from mesophotic to upper bathyal depths. Several evidences suggest that this species is able to tolerate a broad range of temperatures, which allows it to colonize numerous environments in a wide depth range. In the present study, we first provided a detailed ecological characterization of the D. cornigera dense aggregation thriving on the Mantice Shoal (NW Ligurian Sea, Mediterranean Sea). Information on substrate type and inclination, average extension and density, colonies size-class frequency distribution and associated fauna are reported. Then, we presented an extensive review of the available information on the ecology of this species, including 142 new ROV records from the Italian coast (40–1820 m). Results indicated that D. cornigera occurs on a wide range of substrates, including soft bottoms and hardgrounds (outcropping rocks, coralligenous rock and dead cold-water coral frameworks), with significant differences in colony density and size among different substrates. Dendrophyllia cornigera creates three main facies, each characterized by a specific combination of substrate, inclination, depth, and associated fauna. Scattered living colonies, as well as large thanatocoenoses, display a wide geographical and bathymetric distribution. Differently, the facies represented by dense meadows on horizontal soft-bottoms results rare, being reported only from the Mantice Shoal and the Amendolara Bank (Ionian Sea). The radiocarbon age of the thanatocoenoses varies between 400 (Corsica Channel) and 13000 (Vercelli Seamount) years before present. This study highlights the wide adaptability of D. cornigera in terms of environmental settings, changing the current view on the ecology of this species and providing essential insights for the implementation of international deep-sea habitat classification schemes and conservation measures

. Ecological role and phylogenetic position of a new habitat-forming species (Canalipalpata, Sabellidae) from the Mediterranean mesophotic soft-bottoms

This study presents a description of Bispira riccardi sp. nov., a new habitat-forming sabellid polychaete from the mesophotic NW Mediterranean Sea. Individuals, up to 20 cm long, show a peculiar morphology of radioles, thoracic uncini, companion chaetae and ventral shield of the collar. The phylogenetic position of this new taxon in the genus Bispira has been validated using nuclear (18S rRNA) and mitochondrial (COI) markers. Aggregations of B. riccardi sp. nov. were found by ROV on horizontal muddy bottoms between 56 and 85 m, in areas subjected to high trophic inputs. Patches are fragmented and dense (up to 943 individuals m 2) probably accounting for various hectares. A 5-days continuous monitoring, carried out using an autonomous lander, revealed that the contraction of the branchial crown was positively affected by temperature and current, rapidly responding to meteorological events. The filtering activity and high density of these fields suggest a considerable impact on the pelagic-benthic coupling and the amount of organic matter in the sediments. Indeed, meiofaunal abundance and diversity within the aggregations resulted significantly higher than in outer stations. These findings highlight the undisclosed potential of the deep Mediterranean Sea for sabellid diversity and their importance as habitat-forming species on mesophotic soft bottoms

New records of rare species in the Mediterranean Sea (October 2020)

This Collective Article presents information about 21 taxa belonging to seven Phyla (one Ochrophyta, one Porifera, three Cnidaria, two Arthropoda, three Mollusca, one Echinodermata, and ten Chordata) and extending from the western Mediterranean Sea to the Levantine Sea. The new records were reported from nine countries as follows: Spain: first records of three deep-sea species from the Blanes Canyon along the Catalan margin, namely the gorgonian Placogorgia coronata, the bivalve Acesta excavata, and the Azores rockling Gaidropsarus granti; Italy: first record of the mesopsammic nudibranch Embletonia pulchra from Ligurian shallow-waters; first record of the deep-sea carnivorous sponge Lycopodina hypogea from the north-central Tyrrhenian Sea, living in dense clusters over dead black corals; new records of the Portuguese man o’ war Physalia physalis from Sardinian and Sicilian waters; first Italian record of the large asteroid Coronaster briareus from the Ionian Sea; first record of the white grouper Epinephelus aeneus in the northernmost point of the Adriatic Sea; Croatia: first record of the gastropod Haliotis mykonosensis for the Adriatic Sea; Malta: new sightings of Physalia physalis from Maltese waters; Libya: first record of the sand crab Albunea carabus from two localities along the Libyan coast; Greece: first records of the deep-sea black coral Parantipathes larix from the eastern Mediterranean Sea; first verified record of the agujon needlefish Tylosurus imperialis in the Hellenic Ionian Sea; first confirmed record of the brown algae Treptacantha squarrosa in the eastern Mediterranean Sea; new records of three deep-sea fish species from the Aegean Sea, namely the bluntnose sixgill shark Hexanchus griseus, the Atlantic pomfret Brama brama, and the rudderfish Centrolophus niger; new record of the tripletail Lobotes surinamensis from Lesvos Island; new record of the shrimp Brachycarpus biunguiculatus from the gut content of the non-indigenous lionfish Pterois miles; Turkey: new record of the imperi- al blackfish Schedophilus ovalis from Turkish waters; Lebanon: first record of the slender sunfish Ranzania laevis, stranded along the Lebanese coast; Israel: new record, after about 60 years from the last catch, of the spotted dragonet Callionymus maculatus.peer-reviewe

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Large-scale characterization of the deep megabenthic fauna along the Italian coast: diversity, distribution, ecology and vulnerability

The Mediterranean Sea is a relatively small basin characterized by a deep homeothermy, a complex water circulation system, and an intricate network of topographic features, including canyons, seamounts, hydrothermal vents, cold seeps, and abyssal plains. Despite being considered a biodiversity hotspot with a uniquely high percentage of endemic species, the knowledge about its species richness is almost completely confined to coastal ecosystems, and data on deep-sea assemblages are still limited. Over the past 25 years, the advancement of underwater equipment made access to deep-sea environments easier and more cost-effective. In particular, the use of Remotely Operated Vehicles (ROVs) turned out to be a valid method for observing habitats, identifying organisms, and understanding interactions between them and their environment in a non-invasive way. Although its widespread use in the Mediterranean mesophotic and bathyal zones since the beginning of the century, comprehensive studies targeting the characterization of the biodiversity of deep-sea ecosystems from a large-scale perspective are lacking nowadays. For this reason, the aim of the present work was to depict the large-scale biodiversity and distribution patterns of mesophotic and bathyal megabenthic and demersal taxa in the Italian seas. To do this, an ROV archive consisting of 654 dives, obtained from multiple oceanographic campaigns carried out from 2006 to date between 40 and 1825 m along the Ligurian and Tyrrhenian coasts, Sicily Channel, Adriatic and Ionian seas, and offshore localities, has been analysed. Data on species occurrence, abundance, depth, habitat characteristics (substrate and slope), ecology, population structure, and anthropic impact have been collected. The data elaboration in the present work, potentially offering a large number of case studies, was targeted to some charismatic taxa. The visual census allowed the identification of 566 taxa belonging to 13 phyla, including some rare species, like the two Atlantic echinoderms Coronaster briareus (Verrill, 1882) and Holothuria (Vaneyothuria) lentiginosa lentiginosa Marenzeller von, 1892, reported for the first time in Italian waters. Cnidarians and fish were the dominant taxa in terms of occurrence and species richness in all the considered macro-areas. Among anthozoans, the red coral Corallium rubrum (Linnaeus, 1758) resulted widespread along the Italian coast, except in the Adriatic/Ionian seas, with the highest occurrence in the Tyrrhenian Sea, probably because of the deep nutrients-rich currents in this area. Large-scale considerations could be made also for the bathymetric distribution of other taxa: some showed a marked preference for the mesophotic zone, like molluscs, bryozoans, and ascidians, while some were more abundant in the upper bathyal zone, like crustaceans and echinoderms. To disentangle the factors potentially explaining these distributions, species or groups of species must be considered separately. Brachiopods, for example, showed a peak of occurrence in the upper bathyal zone, below the shelf break, especially over outcropping and sub-outcropping rocks showing less competition with arborescent habitat-formers and higher silting levels. Interestingly, the species Novocrania anomala (O. F. Müller, 1776) was very abundant in the bathyal depth range, despite being much more commonly known in shallow submarine caves, probably showing bathophilic conditions. Fifty-three reference habitats have been identified in the studied regions, corresponding to about 80% of the recently described ones for the mesophotic and bathyal zones, including coralligenous accretions, offshore rocks and muddy areas dominated by animal forests, coral reefs, and thanatocoenoses on bathyal muds. This information increased the knowledge on deep habitats, including ones not yet listed in the SPA/RAC classification system. For example, dense aggregations of the yellow scleractinian Dendrophyllia cornigera (Lamarck, 1816) were observed on muddy planes, despite this species has always been considered a typical hard-bottom species, and no reference habitat referring to this type of facies exists yet. The potential of the ecological information included in such a large dataset has been investigated also through another case study targeting gastropods. By noting the ecological preferences of heterobranchs and their bathymetric distribution, it has been possible to hypothesize how, in this group, stenophagy may represent a factor limiting the colonization of the deep sea. With the aim to define the structure and environmental status of the populations of the main habitat-forming anthozoans, detailed data were collected for 27 structuring species. Two species studies were investigated in the present work. In the case of Corallium rubrum (Linnaeus, 1758), 17 major coral areas characterized by highly aggregated colonies were identified, and a size structure skewed towards the smaller sizes was identified in all of them, supporting an effect of the long-term harvesting pressure to which this species is subjected. In addition, high entanglement percentages and mass mortality events in mesophotic populations increased the level of vulnerability of this charismatic species. The pink fan-shaped gorgonian Callogorgia verticillata (Pallas, 1766) was present in all the Italian seas, with seven structured forests identified at mesophotic depths on horizontal rocky bottoms. The overall modal size class of the colonies was 11-30 cm, even if distinctive juvenile and adult cohorts coexisted in some sites. High entanglement percentages were reported in a few areas subjected to significant longline fishing pressure, supporting the identification of priority protection measures for these sites. Monitoring protocols and conservation strategies greatly benefit from the information extrapolated from datasets such as the one built here. Two different case studies were considered here, targeting mesophotic rocky reefs dominated by coral forests and bathyal Cold-Water Coral reefs. Considerations on the abundance of the charismatic species Astrospartus mediterraneus (Risso, 1826) could be made considering the data collected during ten years of surveys within the Marine Strategy Framework Directive, targeting the mesophotic diversity along the Ligurian coast. The variations in the abundance of the basket star resulted to be mainly related to the amount of rainfall and the density of gorgonians. Finally, pluri-annual investigations focused on two Tyrrhenian CWCs areas, coupled with photogrammetric techniques, constituted the baseline to propose a standard monitoring protocol for bathyal CWC-dominated environments. In the last century, the knowledge on the diversity, composition, distribution, and vulnerability of deep environments has become of primary interest. To employ non-invasive methods, such as ROVs, is a valid alternative to traditional destructing methods. They allow to collect a large amount of data on different aspects of the deep-sea habitats and fauna, over a wide geographic and temporal extent. This is fundamental to provide effective monitoring and conservation strategies, in a large-scale, long-term perspective

Study of temporal patterns in the gravitational lensed blazar PKS1830-211 with the Fermi Large Area Telescope

PKS1830-211 is classified as an Active Galactic Nuclei (AGN). Within the AGN taxonomy, it belongs to the blazars class, the AGN that present a relativistic jet closely aligned with Earth. PKS1830-211 is one of the brightest blazars detected by the Fermi-LAT and is also a remarkable case of strong gravitational lensing. Two galaxies are located in the line of sight between the observer and the blazar, and act as a lens. Their strong gravitational field bends light and splits the image into two primary images. This modifies the travel time and, therefore, the light rays that originate at the same time from the blazar reach the observer in different instants. The aim of the thesis work consists in developing a pipeline to pinpoint the potential temporal delay in gamma-rays between the two mostly magnified images of PKS 1830-211

Possible Population Growth of <i>Astrospartus mediterraneus</i> (Risso, 1826) (Ophiuroidea, Gorgonocephalidae) in the Mediterranean Sea

During the last decades, the number of observations of the basket star Astrospartus mediterraneus (Risso, 1826) in the Mediterranean Sea has significantly grown, thanks to SCUBA diver and ROV sightings, citizen reports, as well as particularly large catches by the artisanal fishery. Having been generally considered rare in many areas of the basin, such a long-term increase of records might assign to this basket star the putative role of a winner species in the context of climate changes. In the present study, we combined the overall literature information with the data available for the Ligurian Sea collected during extensive ROV campaigns conducted between 2012 and 2022 at a depth ranging from 20 to 123 m, to better understand the distribution and abundance of this species. The basket star was observed in almost the whole explored bathymetric range living on gorgonians (Eunicella cavolini, E. verrucosa, Paramuricea clavata, and Leptogorgia sarmentosa) and massive sponges (Aplysina cavernicola, Sarcotragus foetidus, Spongia lamella, and Axinella polypoides). In the considered period, the number of recorded specimens did not show a clear trend, but differences emerged over years and months. These variations were strongly correlated with rainfall amounts that, in oligotrophic waters, such as those of the Ligurian Sea, represent an important input of organic matter for these passive filter feeders, especially in the summertime