768 research outputs found

    FROM "MODELS" TO "REALITY", AND RETURN.SOME REFLECTIONS ON THE INTERACTION BETWEEN SURVEYAND INTERPRETATIVE METHODS FOR BUILT HERITAGE CONSERVATION

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    It's well known that more and more accurate methodologies and automatic tools are now available in the field of geometric survey and image processing and they constitute a fundamental instrument for cultural heritage knowledge and preservation; on the other side, very smart and precise numerical models are continuously improved and used in order to simulate the mechanical behaviour of masonry structures: both instruments and technologies are important part of a global process of knowledge which is at the base of any conservation project of cultural heritage. Despite the high accuracy and automation level reached by both technologies and programs, the transfer of data between them is not an easy task and defining the most reliable way to translate and exchange information without data loosing is still an open issue. The goal of the present paper is to analyse the complex process of translation from the very precise (and sometimes redundant) information obtainable by the modern survey methodologies for historic buildings (as laser scanner), into the very simplified (may be too much) schemes used to understand their real structural behaviour, with the final aim to contribute to the discussion on reliable methods for cultural heritage knowledge improvement, through empiricism

    Dust and dark Gamma-Ray Bursts: mutual implications

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    In a cosmological context dust has been always poorly understood. That is true also for the statistic of GRBs so that we started a program to understand its role both in relation to GRBs and in function of z. This paper presents a composite model in this direction. The model considers a rather generic distribution of dust in a spiral galaxy and considers the effect of changing some of the parameters characterizing the dust grains, size in particular. We first simulated 500 GRBs distributed as the host galaxy mass distribution, using as model the Milky Way. If we consider dust with the same properties as that we observe in the Milky Way, we find that due to absorption we miss about 10% of the afterglows assuming we observe the event within about 1 hour or even within 100s. In our second set of simulations we placed GRBs randomly inside giants molecular clouds, considering different kinds of dust inside and outside the host cloud and the effect of dust sublimation caused by the GRB inside the clouds. In this case absorption is mainly due to the host cloud and the physical properties of dust play a strong role. Computations from this model agree with the hypothesis of host galaxies with extinction curve similar to that of the Small Magellanic Cloud, whereas the host cloud could be also characterized by dust with larger grains. To confirm our findings we need a set of homogeneous infrared observations. The use of coming dedicated infrared telescopes, like REM, will provide a wealth of cases of new afterglow observations.Comment: 16 pages, 8 figures, accepted by A&

    Applications of DMDs for astrophysical research

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    A long-standing problem of astrophysical research is how to simultaneously obtain spectra of thousands of sources randomly positioned in the field of view of a telescope. Digital Micromirror Devices, used as optical switches, provide a most powerful solution allowing to design a new generation of instruments with unprecedented capabilities. We illustrate the key factors (opto-mechanical, cryo-thermal, cosmic radiation environment,...) that constrain the design of DMD-based multi-object spectrographs, with particular emphasis on the IR spectroscopic channel onboard the EUCLID mission, currently considered by the European Space Agency for a 2017 launch date.Comment: 10 pages, Proc. SPIE 721

    Integration of historical GIS data in a HBIM system

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    The integration between BIM (Building Information Modeling) and GIS (Geographic Information System) is currently a highly debated research topic. However, the effective integration of the two workflows in a unique information system is still an open research field, especially when dealing with Cultural Heritage (CH). The paper describes an ongoing research on the development of a web information system able to integrate BIM and GIS data, with particular focus on the analysis of the historicized city and its main buildings over time. Three main aspects, in particular, are considered more relevant: (i) conceptual data organization to integrate GIS and BIM in a single environment; (ii) integration of data belonging to different historical periods for analyses over time (4D); (iii) integration into the system of datasets already structured in pre-existing HGIS and HBIM. Most (if not all) of the attributes must be linked with both 2D and 3D entities. The system should be queryable and with the possibility to edit the information regardless of the actual focus of the current user, either if he is more BIM or GIS oriented. This is one of the main requirement for the system not to be just a simple viewer of BIM and GIS data in a unique software environment. The system can manage, from a spatial point of view, different scales of detail, allowing the connection between data from the architectural scale to the territorial one and, from a temporal point of view, data belonging to different periods. All these features have been designed to meet, in particular, the requirements of CH and realize a Historical BIM-GIS system. Besides, the web architecture allows sharing information even between actors with different digital skills, without the need for specific software installed, and ensures portability and access from mobile devices

    Search for low instability strip variables in the young open cluster NGC 2516

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    In this paper we revise and complete the photometric survey of the instability strip of the southern open cluster NGC 2516 published by Antonello and Mantegazza (1986). No variable stars with amplitudes larger than 0m.020^m.02 were found. However by means of an accurate analysis based on a new statistical method two groups of small amplitude variables have been disentangled: one with periods <0d.25< 0^d.25 (probably δ\delta Scuti stars) and one with periods >0d.025>0^d.025. The position in the HR diagram and the apparent time-scale may suggest that the stars of the second group belong to a recently discovered new class of variables, named γ\gamma Dor variables. They certainly deserve further study. We also present a comparison between the results of the photometric survey and the available pointed ROSAT observations of this cluster.Comment: 7 pages, 2 ps figures. Accepted for P.A.S.

    A successful experimental model for intimal hyperplasia prevention using a resveratrol eluting balloon

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    Objective: Restenosis due to intimal hyperplasia is a major clinical problem that compromises the success of angioplasty and endovascular surgery. Resveratrol (RSV) has demonstrated a beneficial effect on restenosis from angioplasty. Unfortunately, the physicochemical characteristics of RSV reduce the practicality of its immediate clinical application. This work proposes an experimental model aiming to setup an intravessel, elutable, RSV-containing compound. Methods: A 140 mg/mL RSV sterile injectable solution with a suitable viscosity for intravascular administration by drugdelivery catheter (RSV-c) was prepared. This solution was locally administered in the common iliac artery of adult male New Zealand White rabbits using a dedicated device (Genie; Acrostak, Geneva, Switzerland) after the induction of intimal hyperplasia by traumatic angioplasty. The RSV concentrations in the wall artery were determined, and the thickness of the harvested iliac arteries was measured over a 1-month period. Results: The Genie catheter was applied in rabbit vessels, and the local delivery resulted in an effective reduction in restenosis after plain angioplasty. Notably, RSV-c forced into the artery wall by balloon expansion might accumulate in the interstitial areas or within cells, avoiding the washout of solutions. Magnification micrographs showed intimal proliferation was significantly inhibited when RSV-c was applied. Moreover, no adverse events were documented in in vitro or in vivo studies. Conclusions: RSV can be advantageously administered in the arterial walls by a drug-delivery catheter to reduce the risk of restenosis
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