1,166 research outputs found

    Geomorphological survey for lagoon and coastal pond management projects: the Lagoon of Venice and the Orbetello coastal pond study cases

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    RIASSUNTO Questo lavoro riporta l'applicazione del rilevamento geomorfologico attraverso misure plano-altimetriche e batometriche ad alta risoluzione per differenti problematiche ambientali in due aree costiere: la Laguna di Venezia e lo stagno costiero di Orbetello. La programmazione di un piano di gestione e salvaguardia degli ecosistemi ha richiesto, per la laguna di Venezia, il monitoraggio delle tendenze evolutive' dei principali elementi morfologici, mentre per Orbetello la naturalizzazione di alcune casse di colmata. I rilevamenti topografici e batimetrici di dettaglio sono stati effettuati sia mediante strumenti e metodologie tradizionali sia mediante GPS in modalità statica-differenziale e cinematica-differenziale che ha permesso la visualizzazione dei dati in tempo reale ottenendo un diretto controllo delle misure. Queste metodologie, per il rilevamento topografico di alcuni limiti ed elementi morfologici inaccessibili,sono state integrate dal telerilevamento con foto aeree mentre, per la progettazione degli interventi di modella mento delle casse di colmata,dalla mappa tura dei sedimenti superficiali. Infine, la valutazione dei tassi erosivi e deposizionali, è stata effettuata sia con rilevamenti topografici stagionali sia con il confronto di una serie storica di cartografie e di foto aeree. ABSTRACT Environment management plans for lagoonal ecosystems require highly detailed geomorphological maps that cannot be obtained with the standard topographical survey. High resolution topographic and bathymetric measurements were carried out in the Lagoon of Venice and in the Lagoon of Orbetello (ItaIy) both with traditional methods and instrumentation and with DGPS (Differential Global Positioning System) in static and kinematic differential modes, with the purpose of providing the ecosystem management plans for the two lagoons, with detailed geomorphological data. For the Lagoon of Venice the detailed topographic and bathymetric surveys were required for the recognition and quantification of erosion and/or deposition processes active in the Venetian basin survey. The comparison of topographic and bathymetric surveys, since 1931, of aerial photographs and of all available information on the geomorphology of the area, has allowed the recognition and quantification, on a decadal scale, of the rate and trend of erosion and sedimentation and has made it possible to de fine those morphological boundaries impossible to survey due to the inaccessible soft mud. Three field measurements done during the 1996-1997 period have made possible the identification of the present erosion rate in a selected area of a salt marsh subjected to wave action. For the Lagoon of Orbetello very low scale topographic measurements were needed for the "naturalization" of manmade mud flats and salt marshes. The naturalization plan of five artificial islets, made with dredged sediments, required the detailed topographic measurements at very low scale of all the morphological elements in order to recreate a natural environment for a rich transitory, nesting or permanent bird life. In addition, sever l small creeks have been dredged for improve the hydrodynamics of the lagoon and the water exchallge between shallows in the 111art made islets and the main channels and to protect the bird life by making it inaccessible for man and other predacious animals. Overall the combination of traditional survey methods with DGPS and the use of all in house developed software has proved to be very efficient for producing the required for detailed topographic and bathymetric maps of the two study areas. Furthermore the study has provided the management plans for the two different ecosystems with geomorphological data otherwise not available

    Central Acceptance Testing for Camera Technologies for CTA

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    The Cherenkov Telescope Array (CTA) is an international initiative to build the next generation ground based very-high energy gamma-ray observatory. It will consist of telescopes of three different sizes, employing several different technologies for the cameras that detect the Cherenkov light from the observed air showers. In order to ensure the compliance of each camera technology with CTA requirements, CTA will perform central acceptance testing of each camera technology. To assist with this, the Camera Test Facilities (CTF) work package is developing a detailed test program covering the most important performance, stability, and durability requirements, including setting up the necessary equipment. Performance testing will include a wide range of tests like signal amplitude, time resolution, dead-time determination, trigger efficiency, performance testing under temperature and humidity variations and several others. These tests can be performed on fully-integrated cameras using a portable setup at the camera construction sites. In addition, two different setups for performance tests on camera sub-units are being built, which can provide early feedback for camera development. Stability and durability tests will include the long-term functionality of movable parts, water tightness of the camera housing, temperature and humidity cycling, resistance to vibrations during transport or due to possible earthquakes, UV-resistance of materials and several others. Some durability tests will need to be contracted out because they will need dedicated equipment not currently available within CTA. The planned test procedures and the current status of the test facilities will be presented.Comment: 8 pages, 3 figures. In Proceedings of the 34th International Cosmic Ray Conference (ICRC2015), The Hague, The Netherlands. All CTA contributions at arXiv:1508.0589

    Corporate political activity and firm outcomes: A meta-analysis

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    Using meta-analytic methods on a sample of 74 studies, we explore the links between CPA and public policy outcomes, and between CPA and firm outcomes. We find that CPA has at best a weak effect and that it appears to be better at maintaining public policy than changing them

    Maroon-eyed Tree Frogs in the Wild

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    This is where the abstract of this record would appear. This is only demonstration data

    Observations on the Slender-Tailed Meerkat

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    This is where the abstract of this record would appear. This is only demonstration data

    In Situ Treatment of Contaminated Water Environments: The Experiment of the Arsenale Vecchio, Venice Lagoon, Italy

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    We report on the results of an experiment of in situ bioremediation by forced aeration, carried out in the Arsenale Vecchio shipyard dock basin of the Venice Lagoon, Italy. The experimental area is characterized by its limited size and reduced boat traffic. The forced aeration technique chosen for the oxygenation of the highly polluted bottom sediments and of the water column above does not obstruct harbor activities and is unique due to its innovative use of a system of porous pipes laid on the bottom sediments. The general recovery of the polluted shipyard dock basin resulted in the documented return of small fish to the area as an indication of a less polluted environment. Most important the bioremediation of the water body above the bottom sediment favours, with time, the formation of a clean natural sediment capping over the bottom contaminated sediments. Post-experiment control after fifteen months of aeration with no extra oxygen added, shows the presence of clean light grey sediments with no foul septic smell, deposited over the polluted bottom sediments. The experiment has indicated that oxygenation by porous pipe forced aeration could represent a cost effective and environmentally feasible way for the recovery of shallow marine and fresh water systems, in situations where other techniques may not be economically and/or environmentally feasible

    Cosmic Ray Physics with the LOFAR Radio Telescope

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    The LOFAR radio telescope is able to measure the radio emission from cosmic ray induced air showers with hundreds of individual antennas. This allows for precision testing of the emission mechanisms for the radio signal as well as determination of the depth of shower maximum XmaxX_{\max}, the shower observable most sensitive to the mass of the primary cosmic ray, to better than 20 g/cm2^2. With a densely instrumented circular area of roughly 320 m2^2, LOFAR is targeting for cosmic ray astrophysics in the energy range 101610^{16} - 101810^{18} eV. In this contribution we give an overview of the status, recent results, and future plans of cosmic ray detection with the LOFAR radio telescope.Comment: Proceedings of the 26th Extended European Cosmic Ray Symposium (ECRS), Barnaul/Belokurikha, 201
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