1,264 research outputs found

    Upper bounds for the eigenvalues of Hessian equations

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    We prove some upper bounds for the Dirichlet eigenvalues of a class of fully nonlinear elliptic equations, namely the Hessian equationsComment: 15 pages, 1 figur

    Geomorphological hazard and tourist vulnerability along Portofino Park trails (Italy)

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    International audienceThe many trails existing in the coastal area of Portofino Promontory are used by tourists for trekking or as pathways to small villages and beaches. The aim of this paper is to define geomorphological hazard and tourist vulnerability in this area, within the framework of the management and planning of hiking activities in Portofino Natural Park. In particular, processes triggered by gravity, running waters and wave motion, affecting the slopes and the cliff, are considered. The typology of the trails and trail maintenance are also taken into account in relation to weather conditions that can make the excursion routes dangerous for tourists. In conclusion, an operative model is applied for the definition of possible risk scenarios. This model is founded on an inventory and the quantification of geomorphological hazards and tourist vulnerability, in comparison with trail rescue data. The model can be applied to other environments and tourist areas

    Antioxidant capacity and heat damage of powder products from South American plants with functional properties

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    Aim of the study was to evaluate color, total polyphenol content (TPC), antioxidant capacity (ABTS, FRAP, DPPH), reducing sugars and heat damage (furosine, hydroxymethylfurfural, glucosylisomaltol) of 21 commercial powder products obtained from South-American fruits (mesquite, lucuma, camu camu), seeds (amaranth, purple maize), roots and tubers (yacon, maca, mashua, tocosh), bark (cat\u2019s claw) and leaves (graviola). TPC and antioxidant capacity were maximum in camu camu and cat\u2019s claw powders, and minimum in tocosh, amaranth, lucuma and maca; graviola, mashua, purple maize and mesquite also showed good antioxidant attributes. Yacon, mashua and lucuma powders had high reducing sugars content (40.9, 34.4 and 21.2 g/100 g DM, respectively) and heat damage (HMF 146.6 mg/kg, furosine 2399.8 and 2228.4 mg/100 g protein, respectively). Overall, camu camu powder and cat\u2019s claw were the most interesting products, having high levels of total polyphenols and antioxidant capacity together with very low heat damage

    49Cr: Towards full spectroscopy up to 4 MeV

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    The nucleus 49Cr has been studied analysing gamma-gamma coincidences in the reaction 46Ti(alpha,n)49Cr at the bombarding energy of 12 MeV. The level scheme has been greatly extended at low excitation energy and several new lifetimes have been determined by means of the Doppler Shift Attenuation Method. Shell model calculations in the full pf configuration space reproduce well negative-parity levels. Satisfactory agreement is obtained for positive parity levels by extending the configuration space to include a nucleon-hole either in the 1d3/2 or in the 2s1/2 orbitals. A nearly one-to-one correspondence is found between experimental and theoretical levels up to an excitation energy of 4 MeV. Experimental data and shell model calculations are interpreted in terms of the Nilsson diagram and the particle-rotor model, showing the strongly coupled nature of the bands in this prolate nucleus. Nine values of K(pi) are proposed for the levels observed in this experiment. As a by-result it is shown that the values of the experimental magnetic moments in 1f7/2 nuclei are well reproduced without quenching the nucleon g-factors.Comment: 13 pages, 8 figure

    Assessment of shallow landslide risk mitigation measures based on land use planning through probabilistic modelling

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    On October 25, 2011 an extreme rainfall event affected a wide area along the coasts of Cinque Terre (eastern Liguria, northern Italy). Particularly, in the Vernazza catchment, the event triggered hundreds of shallow landslides and a debris flood that caused three casualties. Investigation of slope stability after the event was carried out aiming at defining the most effective mitigation measures which may be adopted in future land use planning. To this objective a susceptibility model was produced and a series of scenarios were simulated using probabilistic methods. The susceptibility model has provided information about landslide conditioning factors on which to act for reducing landslide occurrence and therefore the associated risk. The simulations have taken into consideration the following alternative types of mitigation measures: (1) restoration of abandoned terraces, (2) reforestation of abandoned terraces, (3) use of local structural measures over stretches of potentially unstable hillsides and (4) avoidance of any intervention. The advantages and the disadvantages of proposed mitigation measures for shallow landslide risk are discussed considering the results of the simulations and taking into account their complex interaction with environmental, historical, cultural and socio-economic aspects. The results show that the most effective mitigation strategy for reducing landslide risk at short-term consists of applying structural measures over potentially unstable slopes. However a long-term program promoting the development of agricultural practices on terraced slopes is necessary. In fact, the simulations indicate if no measures are applied to avoid the degradation of the terraced areas, landslide areal frequency would inevitably increase

    Urban geomorphology of Genoa old city (Italy)

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    A multi-year geomorphological surveys of the city of Genoa allowed the creation of an original geomorphological map of the urban environment. The city of Genoa is internationally known for the importance of its port and for the presence of a historic city center recognized as an UNESCO World Heritage since 2006. The research methodology was based on the structuring and analysis of a multi-source geodatabase consisting of information acquired from scientific literature and technical reports, historical and recent photographs and maps, geological and environmental data related to land planning plans, original data from field surveys. Work phases of data elaboration included: 1) a multi-temporal cartographic comparison from the eighteenth-century to year 2016; 2) an analysis of aerial photographs in the period 1936-2016; 3) the interpretation of boreholes data; 4) both surface and underground geomorphological observations within the city centre, by means of field surveys and speleological techniques. The recognition of the former geomorphological setting on which the historical nucleus of Genoa has developed, and the interpretation of its paleogeographic, geological and tectonic conditions, are not an easy task: since the High Middle Ages of the Maritime Republic of Genoa, the superposition of multiple phases of urban sprawl has obliterated original geomorphic conditions. However, interpretation of the rich geodatabase allowed to classify landforms, processes and surficial deposits with respect to their original environment and morphogenesis, i.e due to: running waters, gravity, karst, action of the sea; but, above all, due to human activities. In fact, the entire study area has undergone continuous modifications by man through the all considered time interval, as shown by artificial land fillings at the seaside, alteration of the river network, excavations and fills on the slopes, with the highlighting of significant anthropogenic urban landforms. The geomorphological map support both a morpho-evolutionary and a functional approach to the geomorphological landscape the of Genoa old city: therefore, it can be a useful tool for land planning, also aimed at reducing the geo-hydrological risk that characterizes the urban area

    Transition rates and nuclear structure changes in mirror nuclei 47Cr and 47V

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    Lifetime measurements in the mirror nuclei 47Cr and 47V were performed by means of the Doppler-shift attenuation method using the multidetector array EUROBALL, in conjunction with the ancillary detectors ISIS and the Neutron Wall. The determined transition strengths in the yrast cascades are well described by full pf shell model calculations.Comment: Latex2e, 11 pages, 3 figure

    RAPPRESENTAZIONE IN CARTA DELLE CARATTERISTICHE DEI SENTIERI AI FINI DELLA MITIGAZIONE DEL RISCHIO GEOMORFOLOGICO

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    L’ambiente naturale di alcuni particolari ambiti geografici è in rapida evoluzione non solo per quanto riguarda le sue variabili, legate alle tendenze climatiche in atto, ma anche in relazione all’aumentata frequentazione turistica. La maggiore diffusione dei mezzi di risalita in montagna e di navigazione lungo le coste, rende possibile l’accesso anche a siti altrimenti difficilmente raggiungibili: ciò porta ad un contatto rapido e diretto con ambienti talvolta mutevoli in tempi brevi. La crescente richiesta di una maggiore conoscenza dell’ambiente naturale, che si esplica per lo più attraverso la frequentazione della rete sentieristica, implica la necessità di abbinare alle proposte di percorsi ed itinerari, note illustrative e carte tematiche di immediata lettura, che evidenzino sia i siti di interesse naturalistico - culturale sia le possibili situazioni di rischio e di difficoltà di percorrenza degli itinerari stessi. Esistono infatti alcuni elementi morfologici del territorio che di per sé non costituiscono una pericolosità in senso stretto ma che, a seconda delle capacità del fruitore, possono essere fonte indiretta di danno, in quanto rendono difficile l’attraversamento di alcuni punti specifici o la percorrenza di particolari tratti di sentiero. Contemporaneamente la stagionalità in alcune regioni climatiche e la variabilità meteorologica possono incrementare sia la pericolosità sia la vulnerabilità e di conseguenza il rischio per il frequentatore. Obiettivo del presente lavoro è quello di proporre una simbologia adeguata da inserire sulle carte dei sentieri, e più specificatamente su quelle geoturistiche, per una rapida e facile identificazione di specifiche situazioni riscontrabili lungo itinerari: questi simboli, che dovranno riferirsi solo alla percorribilità dell’itinerario e non alla valorizzazione naturalistica dello stesso, andranno rappresentati su base topografica separata, al fine di non appesantire la lettura dell’elaborato cartografico principale e dovranno fornire solo informazioni oggettive che saranno poi interpretate dal fruitore dell’itinerario. La simbologia e le note terranno conto sia delle caratteristiche costanti dei sentieri che degli elementi variabili, in funzione anche delle condizioni climatiche o stagionali, a seconda dei diversi ambienti interessati

    Remote sensing techniques applied to geomorphological mapping of rocky coast: the case study of Gallinara Island (Western Liguria, Italy)

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    Geomorphological survey and mapping of the emerged and submerged coastal areas, particularly addressed to evaluate sea cliff instability within the assessment of coastal hazard and risk mitigation measures, require high resolution and georeferenced spatial data. Remote sensing techniques fully satisfy these needs and allow to obtain all information in a single short-lived survey campaign. An integrated survey by means of laser scanner and multibeam techniques coupled with aerial photos interpretation has been experienced along the rocky coast of the Gallinara Island (Western Liguria, Italy). The small extent of Gallinara, together with its particular meteo-marine climate conditions, makes the island a noteworthy case study. Multibeam and laser scanner technologies allowed to reconstruct the submerged and emerged rocky coast at high resolution. The accuracy of the 3D surface reconstructed by means of laser scanner used in profiler mode was tested and validated, by comparing with the static laser scanner survey method. The resulting data allowed to obtain significant geological and geomorphological information leading to the definition of rocky cliff stability conditions. \ua9 2019, \ua9 2019 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group

    Approximate particle number projection for finite range density dependent forces

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    The Lipkin-Nogami method is generalized to deal with finite range density dependent forces. New expressions are derived and realistic calculations with the Gogny force are performed for the nuclei 164^{164}Er and 168^{168}Er. The sharp phase transition predicted by the mean field approximation is washed out by the Lipkin-Nogami approach; a much better agreement with the experimental data is reached with the new approach than with the Hartree-Fock_Bogoliubov one, specially at high spins.Comment: 5 pages, RevTeX 3.0, 3 postscript figures included using uufiles. Submitted to Phys. Rev. Let
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