Summary
An updated, corrected checklist of both native and established alien freshwater fish species in Italy is given based on molecular, morphological and biogeographical data. Some 12 native ...species, reported as conspecific with transalpine species in official Italian ichthylogical literature, are in fact endemics. Previous taxonomic confusion has resulted in the introduction of several alien species, either with official stockings or mixed in as impurities. Rehabilitated species include the cyprinids Scardinius hesperidicus, Scardinius scardafa and Telestes savigny from northern Italy, as well as Squalius ruffoi and the Telestes comes from southern Italy. Squalius albus is a junior synonym of S. squalus. The endemic gudgeon, previously assigned to the genus Romanogobio, is returned to the genus Gobio (G. benacensis). Phoxinus lumaireul is a junior synonym of P. phoxinus. Among the Salmonidae, Salmo cenerinus is a junior synonym of S. marmoratus, while Salmo farioides represents the trout species of the Adriatic lineage for which a neotype is designated. Thymallus aeliani represents the endemic lineage of grayling of the Adriatic populations. The esocid Esox cisalpinus is an endemic pike species and Esox flaviae is a junior synonym; the extensive exportation as well as the presence of this species throughout Europe is possibly due to humans. Among sculpins, Cottus scaturigo and C. ferrugineus are junior synonyms of C. gobio. The International Union for Conservation of Nature (IUCN) categories for native species of Italy are updated. At present, 52 native freshwater fish species are listed: 2 are extinct (Acipenser sturio and Huso huso), 12 are critically endangered, 7 endangered, 10 vulnerable, 3 near‐threatened, 15 low concern and 3 data‐deficient; 35 species are the result of human transfers. Among the 51 introduced species, 6 are recently established (Leuciscus leuciscus, Oreochromis niloticus, Poecilia reticulata, Xiphophorus helleri, Amatitlania nigrofasciatus, Hemichromis sp.), 37 are already established, 5 are probably established and 3 are non‐established Chinese carp, maintained in the wild by intensive stockings. The family most involved is the Cyprinidae, with 22 alien and 20 native species.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
ABSTRACT We present the second realization of the International Celestial Reference Frame (ICRF2) at radio wavelengths using nearly 30 years of Very Long Baseline Interferometry observations. ICRF2 ...contains precise positions of 3414 compact radio astronomical objects and has a positional noise floor of ∼40 as and a directional stability of the frame axes of ∼10 as. A set of 295 new "defining" sources was selected on the basis of positional stability and the lack of extensive intrinsic source structure. The positional stability of these 295 defining sources and their more uniform sky distribution eliminates the two greatest weaknesses of the first realization of the International Celestial Reference Frame (ICRF1). Alignment of ICRF2 with the International Celestial Reference System was made using 138 positionally stable sources common to both ICRF2 and ICRF1. The resulting ICRF2 was adopted by the International Astronomical Union as the new fundamental celestial reference frame, replacing ICRF1 as of 2010 January 1.
Current research on underwater 3D imaging methods is mainly addressing long range applications like seafloor mapping or surveys of archeological sites and shipwrecks. Recently, there is an increasing ...need for more accessible and precise close-range 3D acquisition technologies in some application fields like, for example, monitoring the growth of coral reefs or reconstructing underwater archaeological pieces that in most cases cannot be recovered from the seabed. This paper presents the first results of a research project that aims to investigate the possibility of using active optical techniques for the whole-field 3D reconstructions in an underwater environment. In this work we have tested an optical technique, frequently used for in air acquisition, based on the projection of structured lighting patterns acquired by a stereo vision system. We describe the experimental setup used for the underwater tests, which were conducted in a water tank with different turbidity conditions. The tests have evidenced that the quality of 3D reconstruction is acceptable even with high turbidity values, despite the heavy presence of scattering and absorption effects.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
We investigate graphene-based optical absorbers that exploit guided mode resonances (GMRs) attaining theoretically perfect absorption over a bandwidth of few nanometers (over the visible and ...near-infrared ranges) with a 40-fold increase of the monolayer graphene absorption. We analyze the influence of the geometrical parameters on the absorption rate and the angular response for oblique incidence. Finally, we experimentally verify the theoretical predictions in a one-dimensional, dielectric grating by placing it near either a metallic or a dielectric mirror, thus achieving very good agreement between numerical predictions and experimental results.
We propose an innovative approach for the realization of a microwave absorber fully transparent in the optical regime. This device is based on the Salisbury screen configuration, which consists of a ...lossless spacer, sandwiched between two graphene sheets whose sheet resistances are different and properly engineered. Experimental results show that it is possible to achieve near-perfect electromagnetic absorption in the microwave X-band. These findings are fully supported by an analytical approach based on an equivalent circuital model. Engineering and integration of graphene sheets could facilitate the realization of innovative microwave absorbers with additional electromagnetic and optical functionalities that could circumvent some of the major limitations of opaque microwave absorbers.
Water resource recovery facilities (WRRFs) contribute to climate change and air pollution, as they are anthropogenic potential sources of direct and indirect emission of greenhouse gases (GHGs). ...Studies concerning the monitoring and accounting for GHG emissions from WRRFs are of increasing interest. In this study, the floating hood technique for gas collection was coupled with the off-gas method to monitor and apportion nitrous oxide (N2O) and carbon dioxide (CO2) emissions from both aerated and non-aerated tanks in a municipal water resource recovery facility, in order to investigate its carbon footprint (CFP). To our knowledge, this is the first time that the chamber technique was applied to evaluate gas fluxes from the settler, where an emission factor (EF) of 4.71 ∗ 10−5 kgCO2,eq kgbCOD−1 was found. Interesting results were found in the disinfection unit, which was the major contributor to direct N2O emissions (with a specific emission factor of 0.008 kgCO2,eq kgbCOD−1), due to the chemical interaction between hydroxylamine and the disinfectant agent (hypochlorite). The specific emission factor of the biological aerated tank was 0.00112 kgCO2,eq kgbCOD−1. The average direct CO2 emission was equal to 0.068 kgCO2 kgbCOD−1 from the activated sludge tank and to 0.00017 kgCO2 kgbCOD−1 from the secondary clarifier. Therefore, taking into account the contribution of both direct N2O and CO2 emissions, values of 0.069 kgCO2,eq kgbCOD−1, 0.008 kgCO2,eq kgbCOD−1 and 0.00022 kgCO2,eq kgbCOD−1, were found for the net CFP of the aerated compartment, the disinfection unit and the clarifier, respectively.
The plant energy Footprint (eFP) was also evaluated, confirming that the aeration system is the major contributor to energy consumption, as well as to indirect CO2 emission, with a specific eFP of 1.49 kWh kgbCOD−1.
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•CO2 and N2O emitted during wastewater treatment in water resource recovery facilities•Floating hood technique utilised for gas collection•CO2 and N2O emissions from aerated and non-aerated tanks•Comparison of two methods for the measurement of gas fluxes from non-aerated tanks•Contribution of disinfection process to N2O emissions from WRRFs
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Despite the large number of papers on the NH
3
doping of graphene, the achievement of stable n-doped large area CVD (chemical vapor deposition) graphene, which is intrinsically p-doped, is still ...challenging. A control of the NH
3
chemisorption and of the N-bond configuration is still needed. The feasibility of a room temperature high pressure NH
3
treatment of CVD graphene to achieve n-type doping is shown here. We use and correlate data for (a) sheet resistance,
R
sh
, and the Hall coefficient,
R
H
, in van der Pauw configuration, acquired in
real time
during the NH
3
doping of CVD-graphene on a glass substrate, (b) optical measurements of the effect of doping on the graphene Van Hove singularity point at 4.6 eV in the dielectric function spectra by spectroscopic ellipsometry, and of (c) N-bond configuration by XPS to better understand and, finally, control the NH
3
doping of graphene. The discussion is focused on the thermal and time stability of the n-doping after air exposure. A chemical rationale is provided for the NH
3
n-doping based on the interaction of (i) NH
3
with intrinsic oxygen functionalities and defects of CVD graphene and of (ii) C-NH
2
doping centers with acceptor species present in the air.
Covalent molecular n-doping of CVD graphene by post-growth NH
3
high pressure treatment.
Graphene/metal heterojunctions are ubiquitous in graphene-based devices and, therefore, have attracted increasing interest of researchers. Indeed, the literature on the field reports apparently ...contradictory results about the effect of a metal on graphene doping. Here, we elucidate the effect of metal nanostructuring and oxidation on the metal work function (WF) and, consequently, on the charge transfer and doping of graphene/metal hybrids. We show that nanostructuring and oxidation of metals provide a valid support to frame WF and doping variation in metal/graphene hybrids. Chemical vapour-deposited monolayer graphene has been transferred onto a variety of metal surfaces, including d-metals, such as Ag, Au, and Cu, and sp-metals, such as Al and Ga, configured as thin films or nanoparticle (NP) ensembles of various average sizes. The metal-induced charge transfer and the doping of graphene have been investigated using Kelvin probe force microscopy (KPFM), and corroborated by Raman spectroscopy and plasmonic ellipsometric spectroscopy. We show that when the appropriate WF of the metal is considered, without any assumption, taking into account WF variations by nanostructure and/or oxidation, a linear relationship between the metal WF and the doping of graphene is found. Specifically, for all metals, nanostructuring lowers the metal WF. In addition, using gold as an example, a critical metal nanoparticle size is found at which the direction of charge transfer, and consequently graphene doping, is inverted.
Charge transfer between CVD graphene and thin films and nanoparticles of various sizes of Al, Ga, Au, Cu and Ag was probed by various corroborating non-invasive approaches of KPFM, Raman spectroscopy and plasmonic spectroscopic ellipsometry.
A one-dimensional dielectric grating, based on a simple geometry, is proposed and investigated to enhance light absorption in a monolayer graphene exploiting guided mode resonances. Numerical ...findings reveal that the optimized configuration is able to absorb up to 60% of the impinging light at normal incidence for both TE and TM polarizations resulting in a theoretical enhancement factor of about 26 with respect to the monolayer graphene absorption (≈2.3%). Experimental results confirm this behavior showing CVD graphene absorbance peaks up to about 40% over narrow bands of a few nanometers. The simple and flexible design points to a way to realize innovative, scalable and easy-to-fabricate graphene-based optical absorbers.
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