The slow rotation of 253 Mathilde     

Stefano Mottola  William D. Sears  Anders Erikson  Alan W. Harris  Jim W. Young  Gerhard Hahn  Mats Dahlgren  Beatrice E. A. Mueller  Bill Owen  Ricardo Gil-Hutton  Javier Licandro  M. Antonietta Barucci  Claudia Angeli  Gerhard Neukum  Claes-Ingvar Lagerkvist  J. Felix Lahulla 《Planetary and Space Science》1995,43(12)

CCD photometry of the NEAR mission fly-by target 253 Mathilde is presented. Measurements taken during 52 nights of observations, from February to June 1995, allow a rotation period of 17.406±0.010 days and a lightcurve amplitude of 0.45±0.02 mag to be determined. A B-V color index of 0.67±0.02 and a V-R of 0.35±0.02 are measured, which are compatible with C-type membership. The determination of the phase relation results in H = 10.28±0.03 and G = 0.12±0.06. Indications that the lightcurve is not strictly singly-periodic are found. A power-spectrum analysis detects a secondary frequency f₂ = 0.0322±0.0010 d⁻¹, which is interpreted as evidence for a complex rotation state.  相似文献   

Digitization and Scientific Exploitation of the Italian and Vatican Astronomical Plate Archives     

Cesare Barbieri  Carlo Blanco  Beatrice Bucciarelli  Regina Coluzzi  Andrea Di Paola  Luciano Lanteri  Gian Luca Li Causi  Ettore Marilli  Piero Massimino  Vincenzo Mezzalira  Stefano Mottola  Roberto Nesci  Alessandro Omizzolo  Fernando Pedichini  Francesca Rampazzi  Corinne Rossi  Ruggero Stagni  Milcho Tsvetkov  Roberto Viotti 《Experimental Astronomy》2003,15(1):29-43

There is a widespread interest to digitize the precious information contained in the astronomical plate archives, both for the preservation of their content and for its fast distribution to all interested researchers in order to achieve their better scientific exploitation. This paper presents the first results of our large-scale project to digitize the archive of plates of the Italian Astronomical Observatories and of the Specola Vaticana. Similar systems, composed by commercial flat-bed retro-illuminated scanners plus dedicated personal computers and acquisition and analysis software, have been installed in all participating Institutes. Ad-hoc codes have been developed to acquire the data, to test the suitability of the machines to our scientific needs, and to reduce the digital data in order to extract the astrometric, photometric and spectroscopic content. Two more elements complete the overall project: the provision of high quality BVRI CCD sequences in selected fields with the Campo Imperatore telescopes, and the distribution of the digitized information to all interested researchers via the Web. The methods we have derived in the course of this project have been already applied successfully to plates taken by other Observatories, for instance at Byurakan and at Hamburg.  相似文献   

Raman study of apatite amorphised with swift heavy ions under various irradiation conditions     

Christian Weikusat  Ulrich A. Glasmacher  Beatrice Schuster  Christina Trautmann  Ronald Miletich  Reinhard Neumann 《Physics and Chemistry of Minerals》2011,38(4):293-303

Crystallographically oriented Durango fluorapatites were exposed to swift heavy ions (Xe, Ta, Au, U) at different irradiation conditions. Beam-induced sample modifications were investigated with respect to the effect of fluence (10⁹–10¹³ ions/cm²), electronic energy loss (18–27 keV/nm), and pressure (3.6–11.5 GPa) applied during irradiation. In situ high-pressure irradiation was performed in diamond anvil cells. Confocal Raman spectroscopy was used to trace the occurring changes in the crystal lattice. Fragmentation of the crystal specimen depends on the orientation and sample thickness and was found to scale with energy loss and fluence. The radiation damage for irradiation along the c-axis was found to be larger than for the 〈hk0〉 direction, independent of the confining pressure. Observations on samples irradiated at high pressures indicate a stabilising effect, leading to reduced amorphisation in comparison to the samples irradiated without pressure.  相似文献   

A Hercynian suture zone in Sardinia : geological and geochemical evidence     

Beatrice Cappelli  Luigi Carmignani  Francesca Castorina  Anselmo Di Pisa  Giacomo Oggiano  Riccardo Petrini 《Geodinamica Acta》2013,26(1-2):101-118

Abstract

The Hereynian basement of Northern Sardinia consists of two main teetonometamorphic complexes : the Southern Paleozoic Low to Medium Grade Metamorphic Complex (LMGMC) and the Northern (Precaimbrian ?) High Grade Metamorphic Complex (HGMC). These complexes are separateli bu the “Posada-Asinara Line” which is a several kilometer-wide mylonitie belt consisting of micaschist. parag-neiss and quartzite that cuts across all Northern Sardinia and contains scattered hodies of amphibolites with granulile and eclogite facies relies.

Major element composition of ampbibolites indicates they were derived from metamorphosed basalts of tholciitie affinity. REE and the relative abundances of HKS elements strongly suggest an oceanic basaltie prololith (N- and T-typc MORB). A whole-rock Sm-Nd isochron for the amphibolite protoliths yields an age of ea. 960 Ma.

The Northern Sardinia basement can he interpreted as a continental collisional zone with the “Posada-Asinara Line” representing a suture zone squeezed between a crustal nappe (HGMC), which represents the overthrust continental margin. and (he inner portion of the Varisean orogenie wedge, which represents the underthrust continental margin with its Paleozoic cover (LMGMC).

Geological and geochemical evidence indicate that the “Posada-Asinara Line” may he considered as part of the South European Hereynian Suture Zone.  相似文献   

Forest fire effects on groundwater in a coastal aquifer (Ravenna,Italy)          下载免费PDF全文

Beatrice M. S. Giambastiani  Nicolas Greggio  Giovanni Nobili  Enrico Dinelli  Marco Antonellini 《水文研究》2018,32(15):2377-2389

We examined the fire‐induced changes in groundwater recharge rate. This aspect is particularly important in the case of large forested areas growing over a coastal aquifer affected by saltwater intrusion. In the Ravenna coastal area (Italy), pine forests grow on coastal dune belts, overlying a sandy unconfined aquifer, which is strongly affected by marine ingression. Three groundwater profiles across the forest and perpendicular to the coastline were monitored for groundwater level, physical, and chemical parameters. The aims were to define groundwater quality, recharge rate, freshwater volume, and highlight change, which occurred after a forest fire with reference to pre‐fire conditions. Analytical solutions based on Darcy Law and the Dupuit Equation were applied to calculate unconfined flow and compare recharge rates among the profiles. The estimated recharge rates increased in the partially and completely burnt areas (219 and 511 mm year^?1, respectively) compared with the pristine pine forest area (73 mm year^?1). Although pre‐fire conditions were similar in all monitored profiles, a post‐fire decrease in salinity was observed across the burnt forest, along with an increase in infiltration and freshwater lens thickness. This was attributed to decrease canopy interception and evapotranspiration caused by vegetation absence after the fire. This research provided an example of positive forest fire feedback on the quantity and quality of fresh groundwater resources in a lowland coastal aquifer affected by saltwater intrusion, with limited availability of freshwater resources. The fire provided an opportunity to evaluate a new forest management approach and consider the restoration and promotion of native dune herbaceous vegetation.  相似文献   

A Framework for Uncertainty Quantification in One-Dimensional Plant Canopy Flow     

Giacomini  Beatrice  Giometto  Marco G. 《Boundary-Layer Meteorology》2022,182(3):441-469

Boundary-Layer Meteorology - Airborne meteorological in situ measurements as well as stationary measurements at the offshore masts FINO1 and FINO3 in the German Bight are evaluated in order to...  相似文献   

Geomorphological mapping for the valorization of the alpine environment. A methodological proposal tested in the Loana Valley (Sesia Val Grande Geopark,Western Italian Alps)   总被引：1，自引：1，他引：0  

Irene Bollati  Beatrice Crosa Lenz  Enrico Zanoletti  Manuela Pelfini 《山地科学学报》2017,14(6):1023-1038

Geomorphological mapping plays a key role in landscape representation: it is the starting point for many applications and for the realization of thematic maps, such as hazard and risk maps, geoheritage and geotourism maps. Traditional geomorphological maps are useful for scientific purposes but they need to be simplified for different aims as management and education. In tourism valorization, mapping of geomorphological resources (i.e., geosites, and geomorphosites), and of geomorphic evidences of past hazardous geomorphological events, is important for increasing knowledge about landscape evolution and active processes, potentially involving geomorphosites and hiking trails. Active geomorphosites, as those widespread in mountain regions, testify the high dynamicity of geomorphic processes and their link with climatic conditions. In the present paper, we propose a method to produce and to update cartographic supports (Geomorphological Boxes) realized starting from a traditional geomorphological survey and mapping. The Geomorphological Boxes are geomorphological representation of single, composed or complex landforms drawn on satellite images, using the official Italian geomorphological legend (ISPRA symbols). Such cartographic representation is also addressed to the analysis (identification, evaluation and selection) of Potential Geomorphosites and Geotrails. The method has been tested in the upper portion of the Loana Valley (Western Italian Alps), located within the borders of the Sesia Val Grande Geopark, recognized by UNESCO in 2013. The area has a good potential for geotourism and for educational purposes. We identified 15 Potential Geomorphosites located along 2 Geotrails; they were ranked according to specific attributes also in relation with a Reference Geomorphosite located in the Loana hydrographic basin and inserted in official national and regional databases of geosites (ISPRA; Regione Piemonte). Finally, the ranking of Potential Geomorphosites allowed to select the most valuable ones for valorization or geoconservation purposes. In this framework, examples of Geomorphological Boxes are proposed as supports to geo-risk education practices.  相似文献   

Deep seismic reflection evidence for the role of extension in the evolution of continental crust     

Laura Serpa  Beatrice de  Voogd 《Geophysical Journal International》1987,89(1):55-60

Summary. Deep seismic reflection profiling, as well as geologic studies, indicate that extensional basins are a common feature of continental crust. The wide-spread occurrence of extensional basins, combined with published models on the effects of extension on lower crustal rocks, suggests that extensional processes play an important role in the evolution of continental crust. Extension is now recognized to have been the last major tectonic event to affect approximately 50% of the United States. This observation and (he preservation of extensional features in areas which have experienced subsequent episodes of compression, suggests that extensional processes may lead to a strengthening of continental crust. In areas of active extension such as the western United States, seismic and petrologic data, as well as theoretical modeling of heat flow data, suggests that the lower crust may be predominantly intrusive igneous material emplaced during extension and that the present Mohorovicic discontinuity formed during extension. Although the interpretation of the various data is somewhat speculative, we suggest that the volume of continental material in some areas has doubled as a result of extension. Thus, extension may result in the addition of a significant amount of new material to the continents.  相似文献   

Harmonization of environmental measurement     

Hartmut Keune Dr.  A. Beatrice Murray Dr.  Heiner Benking 《GeoJournal》1991,23(3):249-255

A wealth of data on the state of the environment is being created in innumerable programmes world-wide. Optimal use of this data requires that information on its existence is available, that it can be readily accessed and — most important — that the data be compiled and classified in a compatible way. Achieving this is the basic aim of harmonization of environmental measurement. Although great care is generally taken to harmonize data collected within programmes, harmonization between programmes remains a major goal for the future.In 1989 UNEP established an office as a basis for the planned Harmonization of Environmental Measurement Project under the auspices of the Global Environmental Monitoring System (GEMS). The office describes the mission, rationale, and objectives of the project and the concepts underlying the harmonization of information on the environment collected at different levels and in different programmes.  相似文献   

High order discontinuous Galerkin method for simulating miscible flooding in porous media     

Jizhou Li  Beatrice Riviere 《Computational Geosciences》2015,19(6):1251-1268

We present a high-order method for miscible displacement simulation in porous media. The method is based on discontinuous Galerkin discretization with weighted average stabilization technique and flux reconstruction post processing. The mathematical model is decoupled and solved sequentially. We apply domain decomposition and algebraic multigrid preconditioner for the linear system resulting from the high-order discretization. The accuracy and robustness of the method are demonstrated in the convergence study with analytical solutions and heterogeneous porous media, respectively. We also investigate the effect of grid orientation and anisotropic permeability using high-order discontinuous Galerkin method in contrast with cell-centered finite volume method. The study of the parallel implementation shows the scalability and efficiency of the method on parallel architecture. We also verify the simulation result on highly heterogeneous permeability field from the SPE10 model.  相似文献