An integrated reconstruction of the multiannual wave pattern in the gulf of naples (South-Eastern Tyrrhenian Sea, Western Mediterranean Sea)

Surface gravity waves retrieved by a network of HF (High Frequency) radars and measured in situ by an ADCP (Acoustic Doppler Current Profiler) current meter connected to an elastic beacon were used to carry out a multiple-year characterization of the wave field of the Gulf of Naples (south-eastern Tyrrhenian Sea, western Mediterranean). The aim of the work was to create a climatology of the study area and to demonstrate the potential of an integrated platform for coastal studies. The patterns recorded by the different instruments were in agreement with the wave climatology of the southern Tyrrhenian Sea as well as with previous scores for the same area. The results presented in this work also highlight seasonal and interannual consistency in the wave patterns for each site. In a wider context, this study demonstrates the potential of HF radars as long-term monitoring tools of the wave field in coastal basins, and supports the development of integrated observatories to address large-scale scientific challenges such as coastal ocean dynamics and the impact of global change on the local dynamics

Evaluation of HF-radar wave measures in the Gulf of Naples

HF-radar systems are commonly employed for detecting the upper sea currents. Nevertheless, the signal of such systems can be further post-processed for characterizing as well the wave characteristics, though this is a recent application whose reliability has not been yet exhaustively investigated. In this work, we evaluate HF-radar measures of significant wave height, wave mean period and incident direction against the outcomes of two numerical models previously validated. The comparison is developed in the Gulf of Naples (hereinafter GoN), taking advantage of three antennas placed in the locations of Castellamare di Stabia, Portici and Sorrento. First, a wave hindcast defined on a regional scale is employed; then, wave data are down-scaled through a local model defined over a finer resolution (local scale). The agreement between the systems is evaluated through statistical error indexes. Results show good consistency, leaving room for deepening the use of radars for wave data collection

HF Radar Measurements of Surface Waves in the Gulf of Naples (Southeastern Tyrrhenian Sea): Comparison With Hindcast Results at Different Scales

HF radar systems wave measurements are evaluated against numerical simulations in the Gulf of Naples (Southeastern Tyrrhenian Sea). Wave measurements are obtained from three CODAR SeaSonde HF radars installed along the coast of the Gulf of Naples. The numerical models employed are WavewatchIII, implemented on a regional scale with a resolution of about 10 km in longitude and latitude in the whole Mediterranean Sea, and SWAN, implemented with a 200 m resolution in the area of interest. Numerical simulations are also validated against experimental data acquired by a buoy installed offshore the Gulf of Naples. The agreement between HF radar measurements and model hindcasts is evaluated through the estimate of statistical error indices for the main wave characteristics (significant wave height, mean period, and mean direction). The consistency between wave parameters retrieved by HF radars and hindcasted by the models opens the way to future integration of the two systems as well as to the utilization of HF radar wave parameters that could be envisaged for data assimilation in wave models

Gulf of Naples Advanced Model (GNAM): A Multiannual Comparison with Coastal HF Radar Data and Hydrological Measurements in a Coastal Tyrrhenian Basin

High-resolution modelling systems have increasingly become an essential requirement to investigate ocean dynamics over a wide range of spatial and temporal scales, and to integrate the punctual ocean observations. When applied in coastal areas, they also have the potential to provide a detailed representation of transport and exchange processes at the sub-basin scale. This paper presents a validation exercise between the surface fields generated by the regional ocean modeling system (ROMS), developed for the Tyrrhenian Sea and downscaled for the Gulf of Naples (GNAM Gulf of Naples advanced model), and a 4 year-long (2009–2012) record of high-frequency radar (HFR) data. The comparison between hourly and seasonal model results and HFR surface fields is focused on the Gulf of Naples (GoN), where an observational network of three HFR sites has been operational since 2004, and on a specific subdomain characterized by the presence of the Sarno river, a long-term ecological research station (LTER-MC) and one important canyon area. An evaluation on a transect delimiting inshore–offshore zones in the GoN is also presented. The GNAM model was also compared with in situ hydrological parameters of temperatures and salinities retrieved at the LTER-MC fixed monitoring station. According to the skill metrics, basic circulation features are accurately reproduced by the circulation model, despite some model drawbacks in terms of increment of energy content in the surface current field occurring during specific seasonal events. The results allow us to identify potential model errors and to suggest useful improvements, the outcome also confirms the unique capability of HF radar systems to provide fine-scale measurements for the validation of numerical models and to counterbalance the lack of high-resolution measurements in coastal areas. © 2022 by the authors

Core-shell graphene oxide-polymer hollow fibers as water filters with enhanced performance and selectivity

Commercial hollow fiber filters for micro-and ultrafiltration are based on size exclusion and do not allow the removal of small molecules such as antibiotics. Here, we demonstrate that a graphene oxide (GO) layer can be firmly immobilized either inside or outside polyethersulfone-polyvinylpyrrolidone hollow fiber (Versatile PES®, hereafter PES) modules and that the resulting core-shell fibers inherits the microfiltration ability of the pristine PES fibers and the adsorption selectivity of GO. GO nanosheets were deposited on the fiber surface by filtration of a GO suspension through a PES cartridge (cut-off 0.1-0.2 μm), then fixed by thermal annealing at 80 °C, rendering the GO coating stably fixed and unsoluble. The filtration cut-off, retention selectivity and efficiency of the resulting inner and outer modified hollow fibers (HF-GO) were tested by performing filtration on water and bovine plasma spiked with bovine serum albumin (BSA, 66 kDa, ≈15 nm size), monodisperse polystyrene nanoparticles (52 nm and 303 nm sizes), with two quinolonic antibiotics (ciprofloxacin and ofloxacin) and rhodamine B (RhB). These tests showed that the microfiltration capability of PES was retained by HF-GO, and in addition the GO coating can capture the molecular contaminants while letting through BSA and smaller polystyrene nanoparticles. Combined XRD, molecular modelling and adsorption experiments show that the separation mechanism does not rely only on physical size exclusion, but involves intercalation of solute molecules between the GO layers

Energetic plumes over the western Ross Sea continental slope

Rapid descent of dense Drygalski Trough (western Ross Sea, Antarctica) shelf water over the continental slope, within 100 to 250 m thick benthic plumes, is described. Speeds of up to 1.0 m/s are recorded flowing at an average angle of 35° to the isobaths, entraining ambient Lower Circumpolar Deep Water en route. This process is predominant in determining the concentration and placement of the shelf water injected into the deep sea as a precursor Antarctic Bottom Water. Nonetheless, a 4-hour duration pulse of undiluted shelf water was observed at depth (1407 m) directly north of the Drygalski Trough, moving at around 90 degrees to isobaths, and at a speed of 1.4 m/s. Thus the export of Ross Sea shelf water to the deep sea is accomplished within plumes descending at moderate angle to isobaths, punctuated by rapid downhill cascades

Expanding the set of rhodococcal Baeyer–Villiger monooxygenases by high-throughput cloning, expression and substrate screening

To expand the available set of Baeyer–Villiger monooxygenases (BVMOs), we have created expression constructs for producing 22 Type I BVMOs that are present in the genome of Rhodococcus jostii RHA1. Each BVMO has been probed with a large panel of potential substrates. Except for testing their substrate acceptance, also the enantioselectivity of some selected BVMOs was studied. The results provide insight into the biocatalytic potential of this collection of BVMOs and expand the biocatalytic repertoire known for BVMOs. This study also sheds light on the catalytic capacity of this large set of BVMOs that is present in this specific actinomycete. Furthermore, a comparative sequence analysis revealed a new BVMO-typifying sequence motif. This motif represents a useful tool for effective future genome mining efforts.

Graphene oxide nanosheets for drinking water purification by tandem adsorption and microfiltration

Graphene nanosheets have outstanding adsorption efficiency toward organic molecules but the potential as sorbent for water purification is strongly limited by the tedious recovery of the nanosheets after the treatment, which can cause secondary contaminations. Here, we demonstrate that graphene oxide (GO) and reduced GO (rGO) nanosheets aggregation in tap water, enabling their separation by dead-end microfiltration (MF) on commercial polymeric hollow fiber modules. No evidence of GO/rGO contamination was found in microfiltered water and chemical potability of treated water was confirmed by standard protocols. Moreover, GO/rGO can be recovered (by inverting the filtration modality from IN-OUT to OUT-IN), washed and reused, this allowing the regeneration and reuse of both graphene nanosheets and the filtration module. The procedure (called here GO + MF) was optimized on tap water spiked with ofloxacin (OFLOX) or methylene blue (MB), as reference. The optimized procedure was then applied both with GO and rGO to the removal of a mixture of perfluoroalkyl substances (PFASs) from tap water at mu g/L levels, the highest concentration found in water resources abstracted for water consumption. We demonstrate that rGO + MF procedure allows to remove 138 mu g/g of total PFASs in only 30 min, i.e. an efficiency 3-5 times higher than granular activated carbon (43 mu g/g) used in real potabilization plants for PFASs removal

CHARACTERIZATION AND VALORIZATION OF MAIZE LANDRACES FROM VALLE D'AOSTA

During 1949-1950 in Italy begun a formal investigation to characterize maize (Zea mays L.) cultivation. In 1954, started a project for the sampling of all Italian maize landraces; this work ended with the collection of 562 different accessions collected in all regions with the exception of Valle d’Aosta, even if historical cultivation of maize in this Region is well documented. In Italy maize landraces have been extensively grown until the mid of the XX century when the cultivation of hybrid took place due to their significant agronomic performances. Despite that, being Valle d’Aosta a mountain region where intensive maize cultivation never started, it was possible to preserve the presence of some landraces. These local materials, which are still cultivated, mainly at domestic level, have high importance from a genetic and historical point of view. Recently, 5 maize landraces from Valle d’Aosta and 2 landraces from the adjacent Canavese (Piedmont) have been collected and subjected to historic, morphologic and genetic characterization. These landraces were named after the sampling location as it follows: Arnad, Arnad-Crest, Chatillon, Entrebin, Perloz, Bianco Canavese, and Rostrato Canavese. Firstly, on these 6 varieties the historic characterization has been carried out. Information and photographs have been searched in local archives and this was crucial to prove their long presence in all the sampling sites under study. From this historic reconstruction, the variety Entrebin resulted as the one that is better historically characterized. To study the variability and differentiation of landraces from Valle d’Aosta, the genetic characterization was performed by the means of 10 SSR markers tested on 20 samples from each landrace. This study highlighted a significant genetic variability among the landraces and, especially, a good level of differentiation between the accessions under investigation. This last result may be explained by the long reproductive isolation experienced by these materials. Complete morphological characterization is actually ongoing. Preliminary morphological observations revealed that these landraces have, generally, flint kernels with the exception of Bianco Canavese (dent) whose color is variable from white (Bianco Canavese) to dark red (Chatillon). Arnad landrace showed 8 kernel rows, probably being an Eight-rowed Flint while the others presented more rows, like many Derived Races. Interestingly, Perloz and Rostrato Canavese showed kernels with an apical beak which was more pronounced in the latter. This suggest that these two landraces belong to the “Rostrata” group, which is common in mountain areas. The present work confirms the importance of mountain areas in conserving biodiversity and increases the rich Italian maize germplasm with materials well adapted to marginal areas. Such new genetic variability may be used to breed new materials for a more resilient agriculture

Fermions in a Walecka-type cosmology

A simplified Walecka-type model is investigated in a cosmological scenario. The model includes fermionic, scalar and vector fields as sources. It is shown that their interactions, taking place in a Robertson-Walker metric, could be responsible for the transition of accelerated-decelerated periods in the early universe and a current accelerated regime. It is also discussed the role of the fermionic field as the promoter of the accelerated regimes in the early and the late stages of the universe.Comment: 8 pages, 4 figures. To appear in EP