473 research outputs found

    Can an early-warning system help minimize the impacts of coastal storms? A case study of the 2012 Halloween storm, northern Italy

    Get PDF
    Abstract. The Emilia-Romagna early-warning system (ER-EWS) is a state-of-the-art coastal forecasting system that comprises a series of numerical models (COSMO, ROMS, SWAN and XBeach) to obtain a daily 3-day forecast of coastal storm hazard at eight key sites along the Emilia-Romagna coastline (northern Italy). On the night of 31 October 2012, a major storm event occurred that resulted in elevated water levels (equivalent to a 1-in-20- to 1-in-50-year event) and widespread erosion and flooding. Since this storm happened just 1 month prior to the roll-out of the ER-EWS, the forecast performance related to this event is unknown. The aim of this study was to therefore reanalyse the ER-EWS as if it had been operating a day before the event and determine to what extent the forecasts may have helped reduce storm impacts. Three different reanalysis modes were undertaken: (1) a default forecast (DF) mode based on 3-day wave and water-level forecasts and default XBeach parameters; (2) a measured offshore (MO) forecast mode using wave and water-level measurements and default XBeach parameters; and (3) a calibrated XBeach (CX) mode using measured boundary conditions and an optimized parameter set obtained through an extensive calibration process. The results indicate that, while a "code-red" alert would have been issued for the DF mode, an underprediction of the extreme water levels of this event limited high-hazard forecasts to only two of the eight ER-EWS sites. Forecasts based on measured offshore conditions (the MO mode) more-accurately indicate high-hazard conditions for all eight sites. Further considerable improvements are observed using an optimized XBeach parameter set (the CX mode) compared to default parameters. A series of what-if scenarios at one of the sites show that artificial dunes, which are a common management strategy along this coastline, could have hypothetically been constructed as an emergency procedure to potentially reduce storm impacts

    Giant Shape-Persistent Tetrahedral Porphyrin System: Light-Induced Charge Separation

    Get PDF
    Tetraphenylmethane appended with four pyridylpyridinium units works as a scaffold to self-assemble four ruthenium porphyrins in a tetrahedral shape-persistent giant architecture. The resulting supramolecular structure has been characterised in the solid state by X-ray single crystal analysis and in solution by various techniques. Multinuclear NMR spectroscopy confirms the 1 : 4 stoichiometry with the formation of a highly symmetric structure. The self-assembly process can be monitored by changes of the redox potentials, as well as by modifications in the visible absorption spectrum of the ruthenium porphyrin and by a complete quenching of both the bright fluorescence of the tetracationic scaffold and the weak phosphorescence of the ruthenium porphyrin. An ultrafast photoinduced electron transfer is responsible for this quenching process. The lifetime of the resulting charge separated state (800 ps) is about four times longer in the giant supramolecular structure compared to the model 1 : 1 complex formed by the ruthenium porphyrin and a single pyridylpyridinium unit. Electron delocalization over the tetrameric pyridinium structure is likely to be responsible for this effect

    Atomic scale engines: Cars and wheels

    Full text link
    We introduce a new approach to build microscopic engines on the atomic scale that move translationally or rotationally and can perform useful functions such as pulling of a cargo. Characteristic of these engines is the possibility to determine dynamically the directionality of the motion. The approach is based on the transformation of the fed energy to directed motion through a dynamical competition between the intrinsic lengths of the moving object and the supporting carrier.Comment: 4 pages, 3 figures (2 in color), Phys. Rev. Lett. (in print

    Assessment of satellite-derived shorelines automatically extracted from Sentinel-2 imagery using SAET

    Get PDF
    The definition of the shoreline position from satellite imagery is of great interest among coastal monitoring techniques. Understanding the reality mapped by the resulting shorelines and defining their accuracy is of paramount importance. The assessment described in this paper constitutes a validation of the shorelines obtained by using the novel tool SAET (Shoreline Analysis and Extraction Tool) for automatic shoreline extraction. The resulting shorelines applying the different parameters available in SAET are assessed in 9 test sites with diverse morphology and oceanographic conditions along the Atlantic European and Western Mediterranean coasts. The reference data is obtained along large coastal segments (covering up to about 240 km) from nearly coincident very high-resolution satellite images. Different image processing levels and extraction methods have been tested, showing their key role in the accuracy of shoreline position. When defining the approximate shoreline position the Automated Water Extraction Index for images without shadows (AWEInsh) with a 0 threshold generally constitutes the best segmentation method. In turn, the employment of the mathematical morphological operations of dilation or erosion considerably improves the results in certain coastal typologies. On the contrary, the employment of atmospherically-corrected images has a smaller influence on the accuracy of the SDSs. Results support the idea that the magnitude of the errors is strongly related to the specific coastal conditions- In general, the lowest errors appear in low-energetic microtidal sites, contrary to the energetic and mesotidal coasts with gentle slopes. The shoreline errors range between 3.7 m and 13.5 m RMSE (root-mean-square error) among the different coastal types when selecting the most appropriate extraction parameters. The shoreline position identified with SAET shows a similar or better accuracy to that obtained by other tools

    A Robotic arm for optical and gamma radwaste inspection

    Get PDF
    We propose Radibot, a simple and cheap robotic arm for remote inspection, which interacts with the radwaste environment by means of a scintillation gamma detector and a video camera representing its light (< 1 kg) payload. It moves vertically thanks to a crane, while the other three degrees of freedom are obtained by means of revolute joints. A dedicated algorithm allows to automatically choose the best kinematics in order to reach a graphically selected position, while still allowing to fully drive the arm by means of a standard videogame joypad

    Functional characterization of two novel mutations in scn5a associated with brugada syndrome identified in Italian patients

    Get PDF
    Background. Brugada syndrome (BrS) is an autosomal dominantly inherited cardiac disease characterized by “coved type” ST-segment elevation in the right precordial leads, high susceptibility to ventricular arrhythmia and a family history of sudden cardiac death. The SCN5A gene, encoding for the cardiac voltage-gated sodium channel Nav1.5, accounts for ~20–30% of BrS cases and is considered clinically relevant. Methods. Here, we describe the clinical findings of two Italian families affected by BrS and provide the functional characterization of two novel SCN5A mutations, the missense variant Pro1310Leu and the in-frame insertion Gly1687_Ile1688insGlyArg. Results. Despite being clinically different, both patients have a family history of sudden cardiac death and had history of arrhythmic events. The Pro1310Leu mutation significantly reduced peak sodium current density without affecting channel membrane localization. Changes in the gating properties of expressed Pro1310Leu channel likely account for the loss-of-function phenotype. On the other hand, Gly1687_Ile1688insGlyArg channel, identified in a female patient, yielded a nearly undetectable sodium current. Following mexiletine incubation, the Gly1687_Ile1688insGlyArg channel showed detectable, albeit very small, currents and biophysical properties similar to those of the Nav1.5 wild-type channel. Conclusions. Overall, our results suggest that the degree of loss-of-function shown by the two Nav1.5 mutant channels correlates with the aggressive clinical phenotype of the two probands. This genotype-phenotype correlation is fundamental to set out appropriate therapeutical intervention

    Do women ⩾50 years of age need as much screening as women <50 years after they have had negative screening results?

    Get PDF
    To assess the adequacy of a routine screening to identify cervical intraepithelial neoplasia 2 or worse (CIN2+) in women over 50 years of age, a retrospective cohort was set in six Italian organised population-based screening programmes. In all, 287 330 women (1 714 550 person-years of observation, 1110 cases) screened at age 25–64, with at least two cytological screening tests, the first negative, were followed from their first negative smear until a biopsy proven CIN2+ lesion or their last negative smear. For women aged 25–49 and 50–64 years, crude and age-standardised detection rate (DR), cumulative risk (CR), adjusted hazard risk for number of previous negative screens, probability of false-positive CIN2+ after two or more smear tests were calculated. Detection rate is significantly lower over 50 years of age. Multivariable analysis shows a significant protective effect from four screening episodes (DR=0.70, 95% CI: 0.51–0.97); the effect of age ⩾50 is 0.29 (95% CI: 0.24–0.35). The CR of CIN2+ is at least eightfold higher in women <50 (CR=2.06, 95% CI: 1.88–2.23) after one previous negative test than in women ⩾50 years with four screens (CR=0.23, 95% CI: 0.00–0.46). Over 50 years of age, after four tests at least three false-positive cases are diagnosed for every true positive. Benefits arising from cytological screening is uncertain in well-screened older women

    Lithium storage mechanisms in purpurin based organic lithium ion battery electrodes

    Get PDF
    Current lithium batteries operate on inorganic insertion compounds to power a diverse range of applications, but recently there is a surging demand to develop environmentally friendly green electrode materials. To develop sustainable and eco-friendly lithium ion batteries, we report reversible lithium ion storage properties of a naturally occurring and abundant organic compound purpurin, which is non-toxic and derived from the plant madder. The carbonyl/hydroxyl groups present in purpurin molecules act as redox centers and reacts electrochemically with Li-ions during the charge/discharge process. The mechanism of lithiation of purpurin is fully elucidated using NMR, UV and FTIR spectral studies. The formation of the most favored six membered binding core of lithium ion with carbonyl groups of purpurin and hydroxyl groups at C-1 and C-4 positions respectively facilitated lithiation process, whereas hydroxyl group at C-2 position remains unaltered

    Circadian Genes as Exploratory Biomarkers in DMD: Results From Both the mdx Mouse Model and Patients

    Get PDF
    Duchenne muscular dystrophy (DMD) is a rare genetic disease due to dystrophin gene mutations which cause progressive weakness and muscle wasting. Circadian rhythm coordinates biological processes with the 24-h cycle and it plays a key role in maintaining muscle functions, both in animal models and in humans. We explored expression profiles of circadian circuit master genes both in Duchenne muscular dystrophy skeletal muscle and in its animal model, the mdx mouse. We designed a customized, mouse-specific Fluidic-Card-TaqMan-based assay (Fluid-CIRC) containing thirty-two genes related to circadian rhythm and muscle regeneration and analyzed gastrocnemius and tibialis anterior muscles from both unexercised and exercised mdx mice. Based on this first analysis, we prioritized the 7 most deregulated genes in mdx mice and tested their expression in skeletal muscle biopsies from 10 Duchenne patients. We found that CSNK1E, SIRT1, and MYOG are upregulated in DMD patient biopsies, consistent with the mdx data. We also demonstrated that their proteins are detectable and measurable in the DMD patients’ plasma. We suggest that CSNK1E, SIRT1, and MYOG might represent exploratory circadian biomarkers in DMD

    Neutron cross-sections for advanced nuclear systems : The n-TOF project at CERN

    Get PDF
    © Owned by the authors, published by EDP Sciences, 2014 This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly citedThe study of neutron-induced reactions is of high relevance in a wide variety of fields, ranging from stellar nucleosynthesis and fundamental nuclear physics to applications of nuclear technology. In nuclear energy, high accuracy neutron data are needed for the development of Generation IV fast reactors and accelerator driven systems, these last aimed specifically at nuclear waste incineration, as well as for research on innovative fuel cycles. In this context, a high luminosity Neutron Time Of Flight facility, n-TOF, is operating at CERN since more than a decade, with the aim of providing new, high accuracy and high resolution neutron cross-sections. Thanks to the features of the neutron beam, a rich experimental program relevant to nuclear technology has been carried out so far. The program will be further expanded in the near future, thanks in particular to a new high-flux experimental area, now under construction.Peer reviewedFinal Published versio
    corecore