Deprit’s reduction of the nodes revisited     

Luigi Chierchia  Gabriella Pinzari 《Celestial Mechanics and Dynamical Astronomy》2011,109(3):285-301

We revisit a set of symplectic variables introduced by Andre Deprit (Celest Mech 30, 181–195, 1983), which allows for a complete symplectic reduction in rotation invariant Hamiltonian systems, generalizing to arbitrary dimension Jacobi’s reduction of the nodes. In particular, we introduce an action-angle version of Deprit’s variables, connected to the Delaunay variables, and give a new hierarchical proof of the symplectic character of Deprit’s variables.  相似文献   

A roadmap for a dedicated Earth Science Grid platform     

Roberto Cossu  Monique Petitdidier  Julian Linford  Vincent Badoux  Luigi Fusco  Benoit Gotab  Ladislav Hluchy  Giuditta Lecca  Fabrizio Murgia  Camiel Plevier  Philippe Renard  Horst Schwichtenberg  Wim Som de Cerff  Viet Tran  Gerald Vetois 《Earth Science Informatics》2010,3(3):135-148

Due to its intensive data processing and highly distributed organization, the multidisciplinary Earth Science applications community is uniquely positioned for the uptake and exploitation of Grid technologies. Currently Enabling Grids for E-sciencE, and other large Grid infrastructures are already deployed and capable of operational services. So far however, the adoption and exploitation of Grid technology throughout the Earth Science community has been slower than expected. The Dissemination and Exploitation of GRids in Earth sciencE project, proposed by the European Commission to assist and accelerate this process in a number of different ways, had between its main goals the creation of a roadmap towards Earth Science Grid platform. This paper presents the resulting roadmap.  相似文献   

The sensitivity of the tropical circulation and Maritime Continent precipitation to climate model resolution     

R. Schiemann  M.-E. Demory  M. S. Mizielinski  M. J. Roberts  L. C. Shaffrey  J. Strachan  P. L. Vidale 《Climate Dynamics》2014,42(9-10):2455-2468

The dependence of the annual mean tropical precipitation on horizontal resolution is investigated in the atmospheric version of the Hadley Centre General Environment Model. Reducing the grid spacing from about 350 km to about 110 km improves the precipitation distribution in most of the tropics. In particular, characteristic dry biases over South and Southeast Asia including the Maritime Continent as well as wet biases over the western tropical oceans are reduced. The annual-mean precipitation bias is reduced by about one third over the Maritime Continent and the neighbouring ocean basins associated with it via the Walker circulation. Sensitivity experiments show that much of the improvement with resolution in the Maritime Continent region is due to the specification of better resolved surface boundary conditions (land fraction, soil and vegetation parameters) at the higher resolution. It is shown that in particular the formulation of the coastal tiling scheme may cause resolution sensitivity of the mean simulated climate. The improvement in the tropical mean precipitation in this region is not primarily associated with the better representation of orography at the higher resolution, nor with changes in the eddy transport of moisture. Sizeable sensitivity to changes in the surface fields may be one of the reasons for the large variation of the mean tropical precipitation distribution seen across climate models.  相似文献   

Thermal decay of carbonate dimension stones: fabric,physical and mechanical changes     

Gioacchino Francesco Andriani  Luigi Germinario 《Environmental Earth Sciences》2014,72(7):2523-2539

This paper deals with the effects of thermal stresses on selected carbonate rocks used as dimension stones. They are Mesozoic calcareous and dolomitic rocks cropping out in Apulia (southern Italy) that, for their physico-mechanical and aesthetic properties, have always been finding a large application both as ornamental stones and as simple construction materials; their use is attested not only in Italy, in works of archaeological, historical and artistic interest too. The cause–effect relationships of thermal degradation were studied by means of an artificial accelerated ageing test, in order to provide a perspective about the decay of carbonate stones due to diurnal and seasonal temperature fluctuations, as well as thermal shocks during events of fire development. The stone samples were subjected to thermal cycles in a muffle furnace, ranging from 100 to 700 °C; after each cycle, several non-destructive and semi-destructive tests were carried out: mass and volume measurements, mercury intrusion porosimetry, sclerometer tests, ultrasonic tests, thin-section observations and determination of chromatic alterations through image analysis and Munsell charts method. In this way, the qualitative and quantitative modifications induced in fabric, physical and mechanical properties were discussed. The results highlight the fundamental role of depositional and diagenetic fabric that, together with mineralogical composition, represents the most significant discriminating factor in the response of the stone to thermal stresses.  相似文献   

The particle background of the <Emphasis Type="Italic">X-IFU</Emphasis> instrument     

Simone Lotti  Teresa Mineo  Christian Jacquey  Silvano Molendi  Matteo D’Andrea  Claudio Macculi  Luigi Piro 《Experimental Astronomy》2017,44(3):371-385

In this paper we are going to review the latest estimates for the particle background expected on the X-IFU instrument onboard of the ATHENA mission. The particle background is induced by two different particle populations: the so called “soft protons” and the Cosmic rays. The first component is composed of low energy particles (< 100s keV) that get funnelled by the mirrors towards the focal plane, losing part of their energy inside the filters and inducing background counts inside the instrument sensitivity band. The latter component is induced by high energy particles (> 100 MeV) that possess enough energy to cross the spacecraft and reach the detector from any direction, depositing a small fraction of their energy inside the instrument. Both these components are estimated using Monte Carlo simulations and the latest results are presented here.  相似文献   

Intermediate Alkali-Alumino-silicate Aqueous Solutions Released by Deeply Subducted Continental Crust: Fluid Evolution in UHP OH-rich Topaz-Kyanite Quartzites from Donghai (Sulu, China)   总被引：3，自引：0，他引：3  

Frezzotti  Maria Luce; Ferrando  Simona; Dallai  Luigi; Compagnoni  Roberto 《Journal of Petrology》2007,48(6):1219-1241

Minerals, fluid inclusions and stable isotopes have been studiedin ultrahigh-pressure (UHP) OH-rich topaz–kyanite quartzitesfrom Hushan (west of Dongai), in southern Sulu (China). Thequartzites underwent a metamorphic evolution characterized bya peak stage (3·5 GPa and 730–820°C) with theanhydrous assemblage coesite + kyanite I, followed by an earlynear-isothermal decompression stage (2·9 GPa and 705–780°C)with growth of kyanite II, muscovite, and OH-rich topaz, andby decompression-cooling stages, represented by paragonite (1·9GPa and 700–780°C) and pyrophyllite (0·3 GPaand 400°C) on kyanite (I and II) and OH-rich topaz, respectively.These rocks may exhibit unusually low ¹⁸O and D values acquiredbefore undergoing UHP metamorphism. Five distinct fluid generationsare recognized. Type I: concentrated peak solutions rich inSi, Al, and alkalis, present within multiphase inclusions inkyanite I. Type II: CaCl₂-rich brines present during the growthof early retrograde OH-rich topaz. Type III, IV, and V: lateaqueous fluids of variable salinity, and rare CO₂ present duringamphibolite- and late greenschist-facies conditions. A numberof conclusions may be drawn from these relationships that havean effect on fluid evolution in deeply subducted continentalrocks. (1) At a pressure of about 3·5 GPa alkali–alumino-silicateaqueous solutions, with compositions intermediate between H₂Ofluid and melt (H₂O > 25 and 50 wt %) evolved from quartzites,probably generated by dehydration reactions. (2) During earlydecompression stages, at the transition from UHP to high-pressure(2·9 GPa) conditions, brines of external origin withhigher water contents (82 wt % H₂O) initiated the growth ofOH-rich topaz and muscovite. (3) The subsequent decompression,at P <2 GPa, was defined by a limited circulation of NaClaqueous fluids, and CO₂ infiltration. Overall, fluid inclusionsand stable isotopes highlight a metamorphic fluid–rockinteraction characterized by internally derived intermediateaqueous solutions at UHP, followed by infiltration of Cl-richbrines with higher water activities. KEY WORDS: ultrahigh-pressure metamorphism; OH-rich topaz; fluid inclusions; stable isotopes; supercritical liquids  相似文献   

An open dataset for landslides triggered by the 2016 Mw 7.8 Kaikōura earthquake,New Zealand     

Tanyaş  Hakan  Görüm  Tolga  Fadel  Islam  Yıldırım  Cengiz  Lombardo  Luigi 《Landslides》2022,19(6):1405-1420

On November 14, 2016, the northeastern South Island of New Zealand was hit by the magnitude Mw 7.8 Kaikōura earthquake, which is characterized by the most complex rupturing mechanism ever recorded. The widespread landslides triggered by the earthquake make this event a great case study to revisit our current knowledge of earthquake-triggered landslides in terms of factors controlling the spatial distribution of landslides and the rapid assessment of geographic areas affected by widespread landsliding. Although the spatial and size distributions of landslides have already been investigated in the literature, a polygon-based co-seismic landslide inventory with landslide size information is still not available as of June 2021. To address this issue and leverage this large landslide event, we mapped 14,233 landslides over a total area of approximately 14,000 km². We also identified 101 landslide dams and shared them all via an open-access repository. We examined the spatial distribution of co-seismic landslides in relation to lithologic units and seismic and morphometric characteristics. We analyzed the size statistics of these landslides in a comparative manner, by using the five largest co-seismic landslide inventories ever mapped (i.e., Chi-Chi, Denali, Wenchuan, Haiti, and Gorkha). We compared our inventory with respect to these five ones to answer the question of whether the landslides triggered by the 2016 Kaikōura earthquake are less numerous and/or share size characteristics similar to those of other strong co-seismic landslide events. Our findings show that the spatial distribution of the Kaikōura landslide event is not significantly different from those belonging to other extreme landslide events, but the average landslide size generated by the Kaikōura earthquake is relatively larger compared to some other large earthquakes (i.e., Wenchuan and Gorkha).

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Chemical Analysis of Iron Meteorites Using a Hand‐Held X‐Ray Fluorescence Spectrometer          下载免费PDF全文

Maurizio Gemelli  Massimo D'Orazio  Luigi Folco 《Geostandards and Geoanalytical Research》2015,39(1):55-69

We evaluate the performance of a hand‐held XRF (HHXRF) spectrometer for the bulk analysis of iron meteorites. Analytical precision and accuracy were tested on metal alloy certified reference materials and iron meteorites of known chemical composition. With minimal sample preparation (i.e., flat or roughly polished surfaces) HHXRF allowed the precise and accurate determination of most elements heavier than Mg, with concentrations > 0.01% m/m in metal alloy CRMs, and of major elements Fe and Ni and minor elements Co, P and S (generally ranging from 0.1 to 1% m/m) in iron meteorites. In addition, multiple HHXRF spot analyses could be used to determine the bulk chemical composition of iron meteorites, which are often characterised by sulfide and phosphide accessory minerals. In particular, it was possible to estimate the P and S bulk contents, which are of critical importance for the petrogenesis and evolution of Fe‐Ni‐rich liquids and iron meteorites. This study thus validates HHXRF as a valuable tool for use in meteoritics, allowing the rapid, non‐destructive (a) identification of the extraterrestrial origin of metallic objects (i.e., archaeological artefacts); (b) preliminary chemical classification of iron meteorites; (c) identification of mislabelled/unlabelled specimens in museums and private collections and (d) bulk analysis of iron meteorites.  相似文献   

Systematic conservation planning in the Mediterranean: a flexible tool for the identification of no-take marine protected areas     

Maiorano  Luigi; Bartolino  Valerio; Colloca  Francesco; Abella  Alvaro; Belluscio  Andrea; Carpentieri  Paolo; Criscoli  Alessandro; Jona Lasinio  Giovanna; Mannini  Alessandro; Pranovi  Fabio; Reale  Bruno; Relini  Giulio; Viva  Claudio; Ardizzone  Gian Domenico 《ICES Journal of Marine Science》2009,66(1):137-146

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Tectonic role of ophiolite-bearing terranes in the development of the Southern Apennines orogenic belt     

Carmelo Monaco  Luigi Tortorici 《地学学报》1995,7(2):153-160

New data on ophiolite-bearing terranes of the Liguride Complex, together with some information on the terranes of the Sicilide Complex, result in a better understanding of the role and tectonic significance of these units in the construction of the Southern Apennines orogenic belt. The Liguride Complex is composed of two main tectonic units overlain by a thick turbiditic sequence of Late Oligocene-Middle Miocene age. The uppermost one (Frido Unit) is a polydeformed and polymetamorphosed sequence, composed of two tectonic subunits of shales and calc-schists, respectively, containing blocks of ophiolite, garnet gneiss, amphibolites and granitoids. This unit is thrust over the un-metamorphosed terranes (Calabro–Lucano Flysch Unit) consisting of a broken formation with blocks of Late Jurassic ophiolite and their sedimentary cover, Cretaceous-Eocene pelagic sediments and Late Oligocene volcaniclastic deposits. The Frido Unit underwent HP/LT metamorphism (P= 8–10 Kb; T= 400–500 °C) resulting in glaucophane and lawsonite assemblages in the ophiolitic rocks and aragonite in the meta-limestones and calc-schists, followed by greenschist fades metamorphism (P= 4 Kb; T= 300–350 °C). From a structural point of view units of the Liguride Complex comprise structures developed at different structural levels, indicating progressive non-coaxial deformation in response to tectonic transport towards the N-NE. The ophiolite-bearing terranes of the Liguride Complex can be considered as a remnant of an accretionary complex in which the Calabro Lucano Flysch Unit represents the toe of the wedge where frontal accretion processes occur and the Frido Unit is a deeper portion. Emplacement of the Frido Unit is explained as being due to formation of a deep duplex structure during the early stage of continental collision processes. The polarity of tectonic transport provides new evidence that the Liguride Complex represents a suture zone between the Apulian and the Calabrian blocks. The age of collision appears to be not older than late Oligocene. The allochtonous terranes of the Liguride and Sicilide Complexes, therefore, represent a complete accretionary wedge which records, first, subduction of the Neotethys ocean beneath the Calabrian (Europe) continental margin and, later, continental collision with the African block.  相似文献