2,335 research outputs found

    A hybrid model for mapping simplified seismic response via a GIS-metamodel approach

    Get PDF
    In earthquake-prone areas, site seismic response due to lithostratigraphic sequence plays a key role in seismic hazard assessment. A hybrid model, consisting of GIS and metamodel (model of model) procedures, was introduced aimed at estimating the 1-D spatial seismic site response in accordance with spatial variability of sediment parameters. Inputs and outputs are provided and processed by means of an appropriate GIS model, named GIS Cubic Model (GCM). This consists of a block-layered parametric structure aimed at resolving a predicted metamodel by means of pixel to pixel vertical computing. The metamodel, opportunely calibrated, is able to emulate the classic shape of the spectral acceleration response in relation to the main physical parameters that characterize the spectrum itself. Therefore, via the GCM structure and the metamodel, the hybrid model provides maps of normalized acceleration response spectra. The hybrid model was applied and tested on the built-up area of the San Giorgio del Sannio village, located in a high-risk seismic zone of southern Italy. Efficiency tests showed a good correspondence between the spectral values resulting from the proposed approach and the 1-D physical computational models. Supported by lithology and geophysical data and corresponding accurate interpretation regarding modelling, the hybrid model can be an efficient tool in assessing urban planning seismic hazard/risk. © Author(s) 2014

    Brief Communication: A low-cost Arduino®-based wire extensometer for earth flow monitoring

    Get PDF
    Abstract. Continuous monitoring of earth flow displacement is essential for the understanding of the dynamic of the process, its ongoing evolution and designing mitigation measures. Despite its importance, it is not always applied due to its expense and the need for integration with additional sensors to monitor factors controlling movement. To overcome these problems, we developed and tested a low-cost Arduino-based wire-rail extensometer integrating a data logger, a power system and multiple digital and analog inputs. The system is equipped with a high-precision position transducer that in the test configuration offers a measuring range of 1023 mm and an associated accuracy of ±1 mm, and integrates an operating temperature sensor that should allow potential thermal drift that typically affects this kind of systems to be identified and corrected. A field test, conducted at the Pietrafitta earth flow where additional monitoring systems had been installed, indicates a high reliability of the measurement and a high monitoring stability without visible thermal drift

    Co-digestion of macroalgae for biogas production: an LCA-based environmental evaluation

    Get PDF
    Algae represent a favourable and potentially sustainable source of biomass for bioenergy-based industrial pathways in the future. The study, performed on a real pilot plant implemented in Augusta (Italy) within the frame of the BioWALK4Biofuels project, aims to figure out whether seaweed (macroalgae) cultivated in near-shore open ponds could be considered a beneficial aspect as a source of biomass for biogas production within the co-digestion with local agricultural biological waste. The LCA results confirm that the analysed A and B scenarios (namely the algae-based co-digestion scenario and agricultural mix feedstock scenario) present an environmental performance more favourable than that achieved with conventional non-renewable-based technologies (specifically natural gas - Scenario C). Results show that the use of seaweed (Scenario A) represent a feasible solution in order to replace classical biomass used for biofuel production from a land-based feedstock. The improvement of the environmental performances is quantifiable on 10% respect to Scenario B, and 38 times higher than Scenario

    Modeling L- and X-band backscattering of wheat and tests over fields of Pampas

    Get PDF
    A discrete scattering model and a detailed set of ground measurements are used to simulate the backscattering coefficients of wheat fields during the whole growth cycle. Simulations are carried out at L- and X-band, and at HH, VV, and HV polarizations. Wheat fields are located in Pampas (Argentina), and are characterized by low values of plant density. Simulations show that the backscattering coefficient is driven by variations of soil moisture at L-band, particularly for HH polarization, with low vegetation effects. Conversely, the attenuation of vegetation is dominant in producing variations of backscattering coefficients at X-band, particularly for VV polarization. Simulations are compared against experimental data collected over the same Pampas region, using airborne SARAT SAR at L-band and COSMO-SKYMED at X-band. Assuming a surface height standard deviation in a 0.4–0.7 cm range, the simulations generally agree with experimental data, with an RMSE lower than about 2 dB at L-band and X-band, except a limited number of cases. Discrepancies observed in specific conditions are discussed. Overall, the results indicate that a joint use of L- and X-band has a good potential to monitor both soil moisture and vegetation growth

    Narrative-based computational modelling of the Gp130/JAK/STAT signalling pathway.

    Get PDF
    BACKGROUND: Appropriately formulated quantitative computational models can support researchers in understanding the dynamic behaviour of biological pathways and support hypothesis formulation and selection by "in silico" experimentation. An obstacle to widespread adoption of this approach is the requirement to formulate a biological pathway as machine executable computer code. We have recently proposed a novel, biologically intuitive, narrative-style modelling language for biologists to formulate the pathway which is then automatically translated into an executable format and is, thus, usable for analysis via existing simulation techniques. RESULTS: Here we use a high-level narrative language in designing a computational model of the gp130/JAK/STAT signalling pathway and show that the model reproduces the dynamic behaviour of the pathway derived by biological observation. We then "experiment" on the model by simulation and sensitivity analysis to define those parameters which dominate the dynamic behaviour of the pathway. The model predicts that nuclear compartmentalisation and phosphorylation status of STAT are key determinants of the pathway and that alternative mechanisms of signal attenuation exert their influence on different timescales. CONCLUSION: The described narrative model of the gp130/JAK/STAT pathway represents an interesting case study showing how, by using this approach, researchers can model biological systems without explicitly dealing with formal notations and mathematical expressions (typically used for biochemical modelling), nevertheless being able to obtain simulation and analysis results. We present the model and the sensitivity analysis results we have obtained, that allow us to identify the parameters which are most sensitive to perturbations. The results, which are shown to be in agreement with existing mathematical models of the gp130/JAK/STAT pathway, serve us as a form of validation of the model and of the approach itself

    Indagine sul servizio di integrazione socio-didattica per ipovedenti ed ipoacusici della provincia di Verona.

    Get PDF
    Per rispondere in modo adeguato alle esigenze delle persone ipoacusiche ed ipovedenti \ue8 necessario verificare e garantire i livelli di qualit\ue0 del servizio a loro dedicato. In tale contesto l'indagine svolta si presta come formidabile strumento per poter prendere decisioni che potrebbero elevare la qualit\ue0 della vita di soggetti svantaggiati

    An algorithm for operational flood mapping from Synthetic Aperture Radar (SAR) data using fuzzy logic

    Get PDF
    Abstract. An algorithm developed to map flooded areas from synthetic aperture radar imagery is presented in this paper. It is conceived to be inserted in the operational flood management system of the Italian Civil Protection and can be used in an almost automatic mode or in an interactive mode, depending on the user's needs. The approach is based on the fuzzy logic that is used to integrate theoretical knowledge about the radar return from inundated areas taken into account by means of three electromagnetic scattering models, with simple hydraulic considerations and contextual information. This integration aims at allowing a user to cope with situations, such as the presence of vegetation in the flooded area, in which inundation mapping from satellite radars represents a difficult task. The algorithm is designed to work with radar data at L, C, and X frequency bands and employs also ancillary data, such as a land cover map and a digital elevation model. The flood mapping procedure is tested on an inundation that occurred in Albania on January 2010 using COSMO-SkyMed very high resolution X-band SAR data

    Le tecniche di campionamento con risposta casualizzata: metodi ed applicazioni.

    Get PDF
    In circa 30 anni di produzione scientifica sono stati proposti molti modelli alternativi a quelli di Warner (1965) e Simmons (1969) ma nessun risultato \ue8 stato raggiunto se non a fronte di complicazioni nell\u2019impianto di indagine, con riguardo al casualizzatore, tali da rendere i nuovi modelli proposti validi solo da un punto di vista metodologico ma con l\u2019effettiva impossibilit\ue0 di applicarli in indagini reali; infatti si sarebbe esposti sia ad un forte aumento dei costi d\u2019indagine sia ad una elevata aggressivit\ue0 del modello; quest\u2019ultima si rifletterebbe in un alto tasso di non risposta. I modelli a doppia randomizzazione di Mangat e Singh (1990) e di Chang e Liang (1996), qui presi in considerazione, pi\uf9 complessi e pi\uf9 costosi di quelli di riferimento, non introducono addirittura alcun beneficio, n\ue9 in relazione alla protezione della privacy, n\ue9 in relazione alla miglior efficienza. Al pi\uf9 possono risultare parimenti efficienti ma con un costo di impianto pi\uf9 elevato. Il modello di Mangat (1994), pur essendo a randomizzazione singola, risulta equivalente a quello di Simmons ed inoltre non permette di fissare un limite superiore al rischio legato alla risposta negativa nel gruppo Ac. In alcuni casi ci\uf2 potrebbe rappresentare un problema. Questo lavoro suggerisce quindi che un\u2019adeguata analisi dell\u2019efficienza e della protezione della privacy \ue8 sempre necessaria qualora un nuovo modello RR venga proposto.Summary. Randomized response is a method used in statistical surveys whose goal is to reduce or eliminate respons errors which occour when respondents are queired about sensitive or highly personal matters. In this work the goals are to analyze and compare the respondent privacy protection in some randomized response models according to efficiency and privacy protection. We prove that some single and double randomization models give no advantage in terms of efficiency under the condition of equal respondent protection compared to Warner\u2019s and Simmons\u2019 models

    May SARS-CoV-2 diffusion be favored by alkaline aerosols and ammonia emissions?

    Get PDF
    Ammonia is a common factor linking air in bat caves and air pollution in the proximity of agricultural fields treated with livestock farming sewage and slaughterhouses, where important clusters of COVID-19 have recently been reported all over the world. Such a commonality has a further connection with the known behavior of some viruses of the coronavirus family, such as the murine hepatitis virus, whose spike glycoprotein (S) can be triggered to a membrane-binding conformation at pH 8.0. Within the airborne route of virus transmission, with particular relevance for crowded and enclosed environments, these observations have prompted a hypothesis that may represent a contributing cause to interpret the geographical variability of the virus diffusion and the surging rise of COVID-19 cases in slaughterhouses all over the world. The hypothesis is that, in these environments, the SARS-CoV-2 S protein may find on a fraction of the airborne particles an alkaline pH, favorable to trigger the conformational changes, needed to induce the fusion of the viral envelope with the plasma membrane of the target cells
    • …
    corecore