1,918 research outputs found
Estimating mass-wasting processes in active earth slides – earth flows with time-series of High-Resolution DEMs from photogrammetry and airborne LiDAR
Abstract. This paper deals with the use of time-series of High-Resolution Digital Elevation Models (HR DEMs) obtained from photogrammetry and airborne LiDAR coupled with aerial photos, to analyse the magnitude of recently reactivated large scale earth slides – earth flows located in the northern Apennines of Italy. The landslides underwent complete reactivation between 2001 and 2006, causing civil protection emergencies. With the final aim to support hazard assessment and the planning of mitigation measures, high-resolution DEMs are used to identify, quantify and visualize depletion and accumulation in the slope resulting from the reactivation of the mass movements. This information allows to quantify mass wasting, i.e. the amount of landslide material that is wasted during reactivation events due to stream erosion along the slope and at its bottom, resulting in sediment discharge into the local fluvial system, and to assess the total volumetric magnitude of the events. By quantifying and visualising elevation changes at the slope scale, results are also a valuable support for the comprehension of geomorphological processes acting behind the evolution of the analysed landslides
Estimating the Isotopic Altitude Gradient for Hydrogeological Studies in Mountainous Areas: Are the Low-Yield Springs Suitable? Insights from the Northern Apennines of Italy
Several prior studies investigated the use of stable isotopes of water in hydrogeological applications, most on a local scale and often involving the isotopic gradient (evaluated by exploiting the so-called altitude effect), calculated on the basis of rainwater isotopes. A few times, this gradient has been obtained using the stable isotopic contents of low-yield springs in a limited time series. Despite the fact that this method has been recognized by the hydrogeological community, marked differences have been observed with respect to the mean stable isotopes content of groundwater and rainwater. The present investigation compares the stable isotopic signatures of 23 low-yield springs discharging along two transects from the Tyrrhenian sea to the Po Plain of Italy, evaluates the different isotopic gradients and assesses their distribution in relation to some climatic and topographic conditions. Stable isotopes of water show that groundwater in the study area is recharged by precipitation and that the precipitation regime in the eastern portion of the study area is strongly controlled by a shadow effect caused by the Alps chain on the air masses from central Europe. Stable isotopes (in particular the d18O and deuterium excess (d-excess) contents together with the obtained isotopic gradients) allow us to identify in the study area an opposite oriented orographic effect and a different provenance of the air masses. When the windward slope is located on the Tyrrhenian side, the precipitation shows a predominant oceanic origin; when the windward slope moves to the Adriatic side, the precipitation is characterized by a continental origin. The main results of this study confirm the usefulness of low-yield springs and the need for a highly detailed survey-scale hydrological investigation in the mountainous context
Groundwater processes in a complex landslide, northern Apennines, Italy
The hydrogeological characteristics of rototranslationalslides in flysch are complex, due to the inherentanisotropy and heterogeneity of rock masses and related deposits.The paper deals with the hydrogeological characterizationof a reactivated roto-translational slide affecting Cretaceousflysch rocks, located in the northern Apennines ofItaly. Continuous monitoring of groundwater levels, in-situpermeability and pumping tests, hydrochemical and physicalanalyses and Uranine tracers were the adopted prospectingmethods.In this research hydrological monitoring and investigationare summarized in order to define a hydrogeological conceptualmodel of the landslide source area. Results showed thattwo overlaying hydrogeological units exist at the slope scale:the first is unconfined, but highly compartmentalized, andhosted in the fractured and dismembered rock slide body.The second is confined and lays in the undisturbed flyschbelow the sliding surface. The groundwater level in theconfined hydrogeological unit is twenty meters higher thanthe groundwater level in the uppermost one. Moreover, thegroundwater chemistry characterization revealed a rising ofdeep fluids in the landslide area
A note on comonotonicity and positivity of the control components of decoupled quadratic FBSDE
In this small note we are concerned with the solution of Forward-Backward
Stochastic Differential Equations (FBSDE) with drivers that grow quadratically
in the control component (quadratic growth FBSDE or qgFBSDE). The main theorem
is a comparison result that allows comparing componentwise the signs of the
control processes of two different qgFBSDE. As a byproduct one obtains
conditions that allow establishing the positivity of the control process.Comment: accepted for publicatio
Exclusive Photoproduction of the Cascade (Xi) Hyperons
We report on the first measurement of exclusive Xi-(1321) hyperon
photoproduction in gamma p --> K+ K+ Xi- for 3.2 < E(gamma) < 3.9 GeV. The
final state is identified by the missing mass in p(gamma,K+ K+)X measured with
the CLAS detector at Jefferson Laboratory. We have detected a significant
number of the ground-state Xi-(1321)1/2+, and have estimated the total cross
section for its production. We have also observed the first excited state
Xi-(1530)3/2+. Photoproduction provides a copious source of Xi's. We discuss
the possibilities of a search for the recently proposed Xi5-- and Xi5+
pentaquarks.Comment: submitted to Phys. Rev.
The upgrade of the ASACUSA scintillating bar detector for antiproton annihilation measurements
Antiproton annihilations on matter nuclei are usually detected by tracking the charged pions emitted in the process. A detector made of plastic scintillating bars have been built and used in the ASACUSA experiment for the last 10 years. Ageing, movements and transports caused stress on the internal mechanical structure and impacted mostly on the optical readout system which was eventually upgraded: the so far used multi-anode photo-multiplier tubes (PMTs) have been replaced by silicon photomultipliers (SiPM) and the front-end electronics had to be adapted to cope with the new signal formation. This work describes the design and operations of the upgrade, as well as the validation tests with cosmic rays
A novel chemically defined medium for the biotechnological and biomedical exploitation of the cell factory Leishmania tarentolae
The development of media for cell culture is a major issue in the biopharmaceutical industry, for the production of therapeutics, immune-modulating molecules and protein antigens. Chemically defined media offer several advantages, as they are free of animal-derived components and guarantee high purity and a consistency in their composition. Microorganisms of the genus Leishmania represent a promising cellular platform for production of recombinant proteins, but their maintenance requires supplements of animal origin, such as hemin and fetal bovine serum. In the present study, three chemically defined media were assayed for culturing Leishmania tarentolae, using both a wild-type strain and a strain engineered to produce a viral antigen. Among the three media, Schneider's Drosophila Medium supplemented with Horseradish Peroxidase proved to be effective for the maintenance of L. tarentolae promastigotes, also allowing the heterologous protein production by the engineered strain. Finally, the engineered strain was maintained in culture up to the 12th week without antibiotic, revealing its capability to produce the recombinant protein in the absence of selective pressure
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