131 research outputs found

    Scattering and absorption properties of carbon nanohorn-based nanofluids for solar energy applications

    Get PDF
    In this work we investigated the scattering and absorption properties of nanofluids consisting in aqueous suspensions of single wall carbon nanohorns of different morphologies and prepared with different amounts of surfactant. The characteristics of these nanofluids were evaluated in order to use them as direct sunlight absorber fluids in solar devices. The differences in optical properties induced by carbon nanoparticles compared to those of pure water lead to a considerably higher sunlight absorption with respect to the pure base fluid. Scattered light over the total attenuation of light was found to be nearly negligible at NIR wavelengths. Both these effects, together with the possible chemical functionalization of carbon nanohorns, make this new kind of nanofluids very interesting for increasing the overall efficiency of the sunlight exploiting device

    Whole mitochondrial genome sequencing provides new insights into the phylogeography of loggerhead turtles (Caretta caretta) in the Mediterranean Sea

    Get PDF
    Population structure and phylogeography of the loggerhead sea turtle (Caretta caretta) have so far been assessed mainly by mitochondrial DNA (mtDNA) single-gene sequencing studies. However, phylogenetic relationships amongst matrilines, genetic characterisation of rookeries and mixed-stock analyses have suffered from the limited resolution obtained by comparison of relatively short sequences such as from the mtDNA control region. Whole mitogenome sequencing can significantly improve population genetics, particularly in marine organisms showing female natal philopatry. Despite mitogenomics becoming increasingly common in biodiversity monitoring and conservation, only a few complete mitogenomes are available for C. caretta. In this study, we sequenced the complete mtDNA of 61 loggerhead turtles sampled between 2008 and 2021 along the Italian coastline and central Mediterranean Sea. We assigned complete mtDNA haplotypes to dead embryos and bycatch samples, and introduced a first nomenclature for loggerhead mitogenomes. Analysis of mtDNA diversity, Maximum Parsimony and Bayesian phylogenetic reconstruction allowed improved resolution of lineages with respect to studies reporting on partial mtDNA control region sequence comparisons, and we were able to further inform previous analyses on loggerhead ancestry based on control region haplogroups. Overall, whole mitogenome analysis has potential for considerable improvement of evolutionary history and phylogeographic investigations as well as mixed-stock surveys of loggerhead turtles

    A prototype model for evaluating SKA-LOW station calibration

    Get PDF
    The Square Kilometre Array telescope at low-frequency (SKA-Low) will be a phased array telescope supporting a wide range of science cases covering the frequency band 50 - 350 MHz, while at the same time asking for high sensitivity and excellent characteristics. These extremely challenging requirements resulted in a design using 512 groups of 256 log periodic dual polarized antennas each (where each group is called “station”), for a total of 131072 antennas. The 512 stations are randomly distributed mostly within a dense area around the centre of the SKA-Low, and then in 3 arms having 16 station clusters each. In preparation for the SKA Phase 1 (SKA1) System Critical Design Review (CDR), prototype stations were deployed at the Murchison Radio-astronomy Observatory (MRO) site (Western Australia) near the Murchison Widefield Array (MWA) radio telescope. The project involved multiple parties in an International collaboration building and testing different prototypes of the SKA1-Low station near the actual site. This resulted in both organisational and logistic challenges typical of a deployment of the actual telescope. The test set-up involved a phased build-up of the complex station of log-periodic antennas, by starting from the deployment of 48 antennas and related station signal processing (called AAVS1.5, where AAVS stands for Aperture Array Verification System), followed by expansion to a full station (AAVS2.0). As reference a station with dipole antennas EDA2 (EDA: Engineering Development Array) was deployed. This test set-up was used for an extensive test and evaluation programme. All test antenna configurations were simulated in detail by electromagnetic (EM) models, and the prediction of the models was further verified by appropriate tests with a drone-based radio frequency source. Astronomical observations on Sun and galaxy transit were performed with calibrated stations of both EDA2, AAVS1.5 and AAVS2.0. All 3 configurations were calibrated. EM modelling and calibration results for the full station AAVS2.0 and EM verification for the AAVS1.5 station are presented. The comparisons between the behaviour of the log-periodic antennas and the dipoles have advanced our understanding the calibration quality and the technological maturity of the future SKA1-Low array

    A prototype model for evaluating SKA-LOW station calibration

    Get PDF
    The Square Kilometre Array telescope at low-frequency (SKA-Low) will be a phased array telescope supporting a wide range of science cases covering the frequency band 50 - 350 MHz, while at the same time asking for high sensitivity and excellent characteristics. These extremely challenging requirements resulted in a design using 512 groups of 256 log periodic dual polarized antennas each (where each group is called "station"), for a total of 131072 antennas. The 512 stations are randomly distributed mostly within a dense area around the centre of the SKA-Low, and then in 3 arms having 16 station clusters each. In preparation for the SKA Phase 1 (SKA1) System Critical Design Review (CDR), prototype stations were deployed at the Murchison Radio-astronomy Observatory (MRO) site (Western Australia) near the Murchison Widefield Array (MWA) radio telescope. The project involved multiple parties in an International collaboration building and testing different prototypes of the SKA1-Low station near the actual site. This resulted in both organisational and logistic challenges typical of a deployment of the actual telescope. The test set-up involved a phased build-up of the complex station of log-periodic antennas, by starting from the deployment of 48 antennas and related station signal processing (called AAVS1.5, where AAVS stands for Aperture Array Verification System), followed by expansion to a full station (AAVS2.0). As reference a station with dipole antennas EDA2 (EDA: Engineering Development Array) was deployed. This test set-up was used for an extensive test and evaluation programme. All test antenna configurations were simulated in detail by electromagnetic (EM) models, and the prediction of the models was further verified by appropriate tests with a drone-based radio frequency source. Astronomical observations on Sun and galaxy transit were performed with calibrated stations of both EDA2, AAVS1.5 and AAVS2.0. All 3 configurations were calibrated. EM modelling and calibration results for the full station AAVS2.0 and EM verification for the AAVS1.5 station are presented. The comparisons between the behaviour of the log-periodic antennas and the dipoles have advanced our understanding the calibration quality and the technological maturity of the future SKA1-Low array

    Biofuels Policy in Europe Under the Directive 2003/30: An Analysis of Goals, Hindrances, Instruments and Effects

    Full text link
    Up to 2008/2009, biofuels were considered one of the best alternatives to oil consumption in a captive market like transports, being one of the pillars of the 20-20-20 initiative in Europe. Improvement of security of supply through partial substitution of imported oil; reduction of GHGs emissions; improvement of income and employment in the agricultural and rural sectors were the main drivers of the promotion of biofuels in Europe, as well as in the United States and in Brazil. In the European Union biofuels policy was supported through Directive 2003/30. However its effects proved to be disappointing: the consumption of biofuels was expected by the Directive to account for 5.75% share of road fuels in 2010 in the European MSs, but it came early clear that such a target could not be met. Above all, consensus about biofuels decreased sharply when their ability to strongly decrease overall GHGs emissions was questioned, and when they were blamed of being the main responsible of the 2007-2008 food price increase. Finally, a new Directive was approved on April 23rd, 2009, including the request of various certifications to prove the sustainability of biofuels. The paper deals deeply with the biofuel experience in Europe, providing a general analysis of the 2003/30 Directive. It includes an evaluation of the difficulties met in satisfying the requested targets, an assessment of the MSs policies to support biofuels, and a discussion about the main features of the (failed) birth of a new industry

    A revision of the status of Lepadogaster lepadogaster (Teleostei : Gobiesocidae): sympatric subspecies or a long misunderstood blend of species?

    Get PDF
    Molecular (partial mitochondrial 12S ribosomal DNA sequences), morphological and meristic analysis of Lepadogaster lepadogaster lepadogaster, L. l. purpurea and L. zebrina were performed to investigate the relationships between these taxa. On the western shore of mainland Portugal, where the two subspecies of L. lepadogaster occur sympatrically, they differ in microhabitat preferences and their breeding seasons are largely out of phase. This information, combined with data on distribution patterns, led to the following conclusions: Lepadogaster l. purpurea is considered to be a valid species, L. purpurea (Bonnaterre, 1788), different from L. l. lepadogaster, now designated L. lepadogaster (Bonnaterre, 1788). L. zebrina was found to be a synonym of L. lepadogaster. The two newly defined species were found to be in sympatry at Madeira and the Canary islands, the Atlantic coast of the Iberian Peninsula, and the Mediterranean at least as far as Genoa (Italy). Diagnostic characters and a list of synonyms are provided. (C) 2002 The Linnean Society of London, Biological Journal of the Linnean Society, 2002, 76, 327-338

    Tracking Signals of Change in Mediterranean Fish Diversity Based on Local Ecological Knowledge

    Get PDF
    One of the expected effects of global change is increased variability in the abundance and distribution of living organisms, but information at the appropriate temporal and geographical scales is often lacking to observe these patterns. Here we use local knowledge as an alternative information source to study some emerging changes in Mediterranean fish diversity. A pilot study of thirty-two fishermen was conducted in 2009 from four Mediterranean locations along a south-north gradient. Semi-quantitative survey information on changes in species abundance was recorded by year and suggests that 59 fish species belonging to 35 families have experienced changes in their abundance. We distinguished species that increased from species that decreased or fluctuated. Multivariate analysis revealed significant differences between these three groups of species, as well as significant variation between the study locations. A trend for thermophilic taxa to increase was recorded at all the study locations. The Carangidae and the Sphyraenidae families typically were found to increase over time, while Scombridae and Clupeidae were generally identified as decreasing and Fistularidae and Scaridae appeared to fluctuate in abundance. Our initial findings strongly suggest the northward expansion of termophilic species whose occurrence in the northern Mediterranean has only been noted previously by occasional records in the scientific literature

    CONTIGUITÀ ALLA MAFIA: STRUMENTI NORMATIVI DI PREVENZIONE E CONTRASTO.

    No full text
    Il presente lavoro di ricerca indaga il concetto di \u201ccontiguit\ue0 mafiosa\u201d nell\u2019ordinamento italiano. L\u2019elaborato si articola in quattro capitoli. Il primo capitolo \ue8 dedicato all\u2019inquadramento della nozione di \u201ccontiguit\ue0 mafiosa\u201d dal punto di vista della letteratura sociologica. Il secondo capitolo, dopo una specificazione della nozione di \u201ccontiguit\ue0\u201d adottata nella presente ricerca, \ue8 dedicato alla ricostruzione della disciplina vigente nel settore del diritto penale. Oggetto di analisi sono le disposizioni che rendono punibili o puniscono pi\uf9 gravemente condotte di collateralit\ue0 alle associazioni di tipo mafioso. Il terzo capitolo \ue8 invece dedicato agli strumenti delle misure di prevenzione che mirano a prevenire il fenomeno della contiguit\ue0 mafiosa. Il quarto \ue8 infine relativo all\u2019istituto della c.d. documentazione antimafia, dunque nell\u2019ambito del diritto amministrativo, specificamente destinato alla prevenzione del fenomeno nell\u2019ambito delle attivit\ue0 economiche. L\u2019indagine si sviluppa tramite l\u2019analisi delle posizioni emerse in dottrina e in giurisprudenza con riferimento al settore della normativa oggetto di esame, facendo emergere le criticit\ue0 della normativa esaminata. In conclusione al lavoro, ci si confronta con la complessit\ue0 del panorama normativo esaminato, vagliando la possibilit\ue0 di ritenere \u201cesaustiva\u201d la legislazione relativa al fenomeno della \u201ccontiguit\ue0 mafiosa\u201d.The research investigates the concept of \u201cmafia contiguity\u201d in Italian law. The dissertation is structured in four chapters. The first one explains what is \u201cmafia contiguity\u201d from a sociological point of view. The second one, after specifying the concept involved by the dissertation, aims to analyse the current discipline in the criminal law sector. The provisions that make punishable or apply more serious punishments of collateralism to mafia-type associations are the object of analysis. The third chapter deals with the tools of preventive measures aiming to prevent the phenomenon of mafia contiguity. Finally, the fourth relates to the institution of the so-called anti-mafia documentation, therefore in the framework of administrative law, specifically intended for the prevention of the phenomenon in the context of economic activities. The investigation is developed through the analysis of the different positions emerged in doctrine and jurisprudence in this field, with reference to the sector of the legislation under analysis, highlighting the critical issues of the examined legislation. The author deals with the complexity of the regulatory landscape, probing the possibility of considering "exhaustive" the legislation relating to the phenomenon of "mafia contiguity"
    corecore