1,754 research outputs found

    Altimetry data and the elastic stress tensor of subduction zones

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    The maximum shear stress (mss) field due to mass anomalies is estimated in the Apennines, the Kermadec-Tonga Trench, and the Rio Grande Rift areas and the results for each area are compared to observed seismicity. A maximum mss of 420 bar was calculated in the Kermadec-Tonga Trench region at a depth of 28 km. Two additional zones with more than 300 bar mss were also observed in the Kermadec-Tonga Trench study. Comparison of the calculated mss field with the observed seismicity in the Kermadec-Tonga showed two zones of well correlated activity. The Rio Grande Rift results showed a maximum mss of 700 bar occurring east of the rift and at a depth of 6 km. Recorded seismicity in the region was primarily constrained to a depth of approximately 5 km, correlating well to the results of the stress calculations. Two areas of high mss are found in the Apennine region: 120 bar at a depth of 55 km, and 149 bar at the surface. Seismic events observed in the Apennine area compare favorably with the mss field calculated, exhibiting two zones of activity. The case of loading by seamounts and icecaps are also simulated. Results for this study show that the mss reaches a maximum of about 1/3 that of the applied surface stress for both cases, and is located at a depth related to the diameter of the surface mass anomaly

    Stochastic applications of Caputo-type convolution operators with non-singular kernels

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    We consider here convolution operators, in the Caputo sense, with non-singular kernels. We prove that the solutions to some integro-differential equations with such operators (acting on the space variable) coincide with the transition densities of a particular class of L\'evy subordinators (i.e. compound Poisson processes with non-negative jumps). We then extend these results to the case where the kernels of the operators have random parameters, with given distribution. This assumption allows greater flexibility in the choice of the kernel's parameters and, consequently, of the jumps' density function.Comment: 16 page

    Diffusion with space memory modelled with distributed order space fractional differential equations

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    Distributed order fractional differential equations (Caputo, 1995, 2001; Bagley and Torvik, 2000a,b) were fi rst used in the time domain; they are here considered in the space domain and introduced in the constitutive equation of diffusion. The solution of the classic problems are obtained, with closed form formulae. In general, the Green functions act as low pass fi lters in the frequency domain. The major difference with the case when a single space fractional derivative is present in the constitutive equations of diffusion (Caputo and Plastino, 2002) is that the solutions found here are potentially more fl exible to represent more complex media (Caputo, 2001a). The difference between the space memory medium and that with the time memory is that the former is more fl exible to represent local phenomena while the latter is more fl exible to represent variations in space. Concerning the boundary value problem, the difference with the solution of the classic diffusion medium, in the case when a constant boundary pressure is assigned and in the medium the pressure is initially nil, is that one also needs to assign the fi rst order space derivative at the boundary

    Citizenship education through practices and representations

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    La investigación se llevó a cabo en los años 2008 y 2009, con la intención de identificar las prácticas de educación para la ciudadanía más difundidas en la escuela secundaria superior italiana y las representaciones más comunes presentes entre los estudiantes y profesores. Se suministraron 1308 cuestionarios, en 76 clases, correspondientes a tres regiones de Italia (Emilia-Romagna, Lombardía y Sicilia), 68 fichas han sido recopiladas a partir de los sondeos de 46 profesores. Diez de estos 46 profesores fueron también entrevistados directamente. El estudio describe las prácticas más difundidas y los temas fundamentales (predomina la prevención de accidentes de tráfico, medidas preventivas de la salud en general, con especial atención a las drogas, el alcohol, las enfermedades de transmisión sexual y el SIDA.) Se observa una presencia muy limitada de proyectos específicos de dimensión jurídica, política y ética, de la ciudadanía, en cambio los estudiantes muestran expectativas y un deseo de intervención sobre la ciudadanía. También parece importante el análisis de las representaciones implícitas identificadas en las respuestas abiertas de los estudiantes.This research was conducted in 2008 and 2009, and sought to identify the most popular practices of citizenship education in secondary school, as well as the most common representations among students and teachers. 1308 open-ended questions questionnaires were administered to 76 classes across three Italian regions (Emilia-Romagna, Lombardy and Sicily); 68 monitoring cards were compiled by 46 teachers. Ten out of these 46 teachers were also interviewed directly. The study describes the most common practices and the privileged topics (road accidents and health care prevention in general with particular regard to drugs, alcohol, sexually transmitted diseases and HIV were among the most popular). The evidence shows a very limited number of projects specifically related to the legal, political and ethical dimensions of citizenship, whilst students express expectation and desire for intervention. Furthermore, the analysis of the implicit representations identified in the open-ended responses provided by the students seems particularly significant.peerReviewe

    Tavola Rotonda dei Dirigenti

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    Questo contributo racchiude gli interventi di alcuni tra i dirigenti delle sette scuole paritarie e statali coinvolte nella ricerca triennale "Ricerca-azione Istituto Vladimiro Spallanzani", che ha trovato un punto di riflessione condivisa nel Convegno "Scuole che educano, insegnanti creativi in Emilia-Romagna. Una ricerca sul campo" (Sassuolo, MO). Gli interventi mancanti sono comunque ascoltabili e visionabili tramite il link alla videoregistrazione della Tavola rotonda, incluso nel file. Per preparare questo momento, i Dirigenti delle scuole partecipanti avevano ricevuto anticipatamente il Report della ricerca, assieme ad alcune domande-guida che avrebbero dovuto orientare la discussione e costituire una base condivisa per il confronto

    Functional Hyperspectral Imaging by High-Related Vegetation Indices to Track the Wide-Spectrum Trichoderma Biocontrol Activity Against Soil-Borne Diseases of Baby-Leaf Vegetables

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    Research has been increasingly focusing on the selection of novel and effective biological control agents (BCAs) against soil-borne plant pathogens. The large-scale application of BCAs requires fast and robust screening methods for the evaluation of the efficacy of high numbers of candidates. In this context, the digital technologies can be applied not only for early disease detection but also for rapid performance analyses of BCAs. The present study investigates the ability of different Trichoderma spp. to contain the development of main baby-leaf vegetable pathogens and applies functional plant imaging to select the best performing antagonists against multiple pathosystems. Specifically, sixteen different Trichoderma spp. strains were characterized both in vivo and in vitro for their ability to contain R. solani, S. sclerotiorum and S. rolfsii development. All Trichoderma spp. showed, in vitro significant radial growth inhibition of the target phytopathogens. Furthermore, biocontrol trials were performed on wild rocket, green and red baby lettuces infected, respectively, with R. solani, S. sclerotiorum and S. rolfsii. The plant status was monitored by using hyperspectral imaging. Two strains, Tl35 and Ta56, belonging to T. longibrachiatum and T. atroviride species, significantly reduced disease incidence and severity (DI and DSI) in the three pathosystems. Vegetation indices, calculated on the hyperspectral data extracted from the images of plant-Trichoderma-pathogen interaction, proved to be suitable to refer about the plant health status. Four of them (OSAVI, SAVI, TSAVI and TVI) were found informative for all the pathosystems analyzed, resulting closely correlated to DSI according to significant changes in the spectral signatures among health, infected and bio-protected plants. Findings clearly indicate the possibility to promote sustainable disease management of crops by applying digital plant imaging as large-scale screening method of BCAs' effectiveness and precision biological control support

    Experimental and Computational Study of Supercritical Fluid Extraction (SFE) of Omega-3 Components from Fish Oil in Structured Packing

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    The benefits of polyunsaturated fatty acids and their implications for human health have gained scientific attention to their extraction from biological sources, not being produced by the human body. Most known industrial productions of omega-3 fatty acids often work under operating conditions that may degrade these components and they often use toxic or flammable solvents that can adversely affect human health. In this sense, innovative and interesting prospects are provided by Supercritical Fluid Extraction (SFE). In this work, two parallel studies were carried out: an experimental activity in a laboratory apparatus using supercritical carbon dioxide (scCO2) and preliminary computational fluid dynamics (CFD) simulations, limited to the hydrodynamic aspects of the process. In the experimental apparatus a Sulzer® EX structured packing, made up of corrugated metal gauze sheets, was used as the column filler. The study made it possible to identify the optimal operating conditions leading to an enrichment of the starting mixture in Eicosapentaenoic acid (EPA) and Docosahexaenoic acid (DHA), target products. CFD simulations were based on the Volume of Fluid (VOF) approach, suitable to the present complex multiphase system with two phases in close contact (transesterified fish oil and scCO2). The meatus created by the corrugations of the metal gauze was chosen as the calculation domain representative of the system. The computations were performed by the commercial software Ansys Fluent®, which allowed the prediction of the hydrodynamic evolution of the system through transient simulations. CFD predictions were in qualitative agreement with the experimental result

    Identità e conflitti religiosi: piste di formazione interculturale per gli educatori

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    Religious pluralism and multicultural society require specific pedagogical and didactic interventions, especially when “religious” conflicts arise. This study analyzes the empirical data of a workshop, realized in the Faculty of Educational Sciences of Bologna, performed with the case study methodology. After gathering the representations of religious identity and religious conflicts thatwere detected through a questionnaire given to the students, before and after the teaching activity, we noted the need of recover a “dynamic” vision of personal identity to give foundation to the educational intervention.It is necessary to think and plan training courses for educators in order to fulfill the need of concrete encounter and dialogue in an intercultural perspective.Il pluralismo religioso e la società multiculturale richiedono interventi pedagogici e didattici specifici, specie in presenza di conflitti “religiosi”. L’articolo analizza del materiale didattico di un laboratorio, realizzato nella facoltà di Scienze dell’Educazione di Bologna, centrato sulla metodologia dello “studio di caso”. Mettendo a fuoco le rappresentazioni dell’identità religiosa e dei conflitti religiosi rilevate tramite questionario tra gli studenti, prima e dopo l’attività didattica,emerge la necessità di recuperare una visione “dinamica” dell’identità personaleper dare fondamento all’intervento educativo. Occorre pensare e progettarepercorsi formativi, per le professioni educative, tali da mettere questi operatori in grado di far fronte concretamente al bisogno di incontro e di dialogo in prospettiva interculturale
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