Exhibiting the New Mussolinian City: Memories of empire in the World Exhibition of Rome (EUR)     

Anna Notaro 《GeoJournal》2000,51(1-2):15-22

The aim of this paper is to show how fascist imperialist discourses were articulated in a new urban space, just on the outskirts of Rome, and how they affected its design, use and representation. This new city, which should have been the spatial expression of the regime's political, cultural and economical achievements, since its beginning was conceived almost as a mirror image of classical Rome. As her fascist alter-ego, it was imagined as the modern realisation of the ancient dream of reconnecting Rome to the Mediterranean, of bringing Rome to the sea and the sea to Rome, as Mussolini used to say. This was a city that had to represent a strong political desire and ended up as an image of mere representation, a city that was founded to contain a world exhibition and became in itself merely an exhibit. Here I am interested not only in the story the EUR (Esposizione Universale di Roma) buildings tell, but also in what they do, according to a performative view of cultural production. In other words, they are not simply new monuments to be added to Fascism's already powerful iconography, but an integral part of those processes of incorporation and rule at work in the construction of Italy's national/imperial identity.  相似文献   

Instability of the 2+2 body problem     

Andrea Milani  Anna M. Nobili 《Celestial Mechanics and Dynamical Astronomy》1987,41(1-4):153-160

The equations of motion of the 2+2 body problem (two interacting particles in the gravitational field of two much more massive primaries m₁ and m₂ in circular keplerian orbit) have an integral analogous to the Jacobi integral of the circular 2+1 body problem. We show here that with 2+2 bodies this integral does not give rise to Hill stability, i.e. to confinement for all time in a portion of the configuration space not allowing for some close approaches to occur. This is because all the level manifolds are connected and all exchanges of bodies between the regions surroundingm ₁,m ₂ and infinity do not contradict the conservation of the integral. However, it is worth stressing that some of these exchanges are physically meaningless, because they involve either unlimited extraction of potential energy from the binary formed by the small bodies (without taking into account their physical size) or significant mutual perturbations between the small masses without close approach, a process requiring, for the Sun-Jupiter-two asteroids system, timescales longer than the age of the Solar System.  相似文献   

On topological stability in the general three-body problem     

Andrea Milani  Anna M. Nobili 《Celestial Mechanics and Dynamical Astronomy》1983,31(3):213-240

The confining curves in the general three-body problem are studied; the role of the integralc ² h (angular momentum squared times energy) as bifurcation parameter is established in a very simple way by using symmetries and changes of scale. It is well known (Birkhoff, 1927) that the bifurcations of the level manifolds of the classical integrals occur at the Euler-Lagrange relative equilibrium configurations. For small values of the mass ratio ε=m ₃/m ₂ both the positions of the collinear equilibrium points and thec ² h integral are expanded in power series of ε. In this way the relationship is found between the confining curves resulting from thec ² h integral in the general problem, and the zero velocity curves given by the Jacobi integral in the corresponding restricted problem. For small values of ε the singular confining curves in the general and in the restricted problem are very similar, but they do not correspond to each other: the offset of the two bifurcation values is, in the usual, system of units of the restricted problem, about one half of the eccentricity squared of the orbits of the two larger bodies. This allows the definition of an approximate stability criterion, that applies to the systems with small ε, and quantifies the qualitatively well known destabilizing effect of the eccentricity of the binary on the third body. Because of this destabilizing effect the third body cannot be bounded by any topological criterion based on the classical integrals unless its mass is larger than a minimum value. As an example, the three-body systems formed by the Sun, Jupiter and one of the small planets Mercury, Mars, Pluto or anyone of the asteroids are found to be ‘unstable’, i.e. there is no way of proving, with the classical integrals, that they cannot cross the orbit of Jupiter. This can be reliably checked with the approximate stability criterion, that given for the most important three-body subsystems of the Solar System essentially the same information on ‘stability’ as the full computation of thec ² h integral and of the bifurcation values.  相似文献   

Reconstruction of the conditions that initiate landslide movement in weathered silty clay terrain: effects on the historic and architectural heritage of Pietrapertosa, Basilicata, Italy     

L. Coppola  R. Nardone  P. Rescio  E. Bromhead 《Landslides》2006,3(4):349-359

Understanding the causes of slope development, particularly the initiation of movement, requires knowledge of a set of factors (usually associated with groundwater) that are often difficult to determine. To perform a back-analysis of the failure conditions of the silty-clay terrains underlying the monastery of San Francis, which was built on the slope of the Valle della Torre, at Pietrapertosa (Potenza), the slope was analyzed by means of a limit-equilibrium approach, to determine the stability coefficient (F _s) in relation to the pore water pressure regime. It has been possible to apply linear regression to establish a relation between rainfall and fluctuations of the water table in long duration records of both and thus to obtain the amount of rainfall that is likely to correspond to the critical value of the piezometric level at which the weathered silty-clay material will fail. In this way, the difficulty of applying the various simulations that define the complex relationships between water infiltration and water table recharge has been avoided. In the study area, the hydrological behavior of the 12-m thick weathered horizon has been represented by flow lines, which, in section, are equipotential lines parallel to the slope.  相似文献   

Macroalgal distribution patterns in a shallow, soft-bottom lagoon, with emphasis on the nonnativeGracilaria vermiculophylla andCodium fragile     

Mads Solgaard Thomsen  Karen J. McGlathery  Anna Christina Tyler 《Estuaries and Coasts》2006,29(3):465-473

We determined the distribution of macroalgae in Hog Island Bay, a shallow coastal lagoon in Virginia, USA, seasonally at 12 sites from 1998 to 2000 and at 3 representative sites from 2000 to 2002. We analyzed macroalgal biomass, taxonomic richness, and abundance of two non-native species, the cryptic invaderGracilaria vermiculophylla and the conspicuousCodium fragile, with respect to season, location (mainland, mid lagoon, barrier island sites), and elevation (intertidal, subtidal). Taxonomic richness, total algal biomass, and nonnative biomass peaked in the summer months when temperature and light availability were highest. A few stress tolerant and ephemeral algae dominated the algal assemblage.G. vermiculophylla constituted 74% of the entire algal biomass, was the most abundant alga in all seasons, locations, and elevation levels, and was positively correlated with taxonomic richness and abundance of filamentous species.Ulva curvata, Bryopsis plumosa, andC. fragile accounted for an additional 16% of the algal biomass. There are distinct habitats in Hog Island Bay that can be classified into low diversity-low biomass regions near the mainland and barrier islands and high diversity-high biomass regions in the open mid lagoon, where abundant shells for attachment and intermediate levels of water column nutrients and turbidity likely create better growth conditions. Taxonomic richness and biomass were higher in subtidal than intertidal zones, presumably due to lower desiccation stress. This study provides an example of how a single invasive species can dominate an entire assemblage, both in terms of biomass (being most abundant in all seasons, locations, and tidal levels) and species richness (correlating positively with epiphytic filamentous taxa). By adding hard-substratum structural complexity to a relatively homogenous soft-substratum system,G. vermiculophylla increases substratum availability for attachment and entanglement of other algal species and enhances local diversity. Without widespread and abundantG. vermiculophylla, taxa likePolysiphonia, Ceramium, Bryopsis, Ectocarpus, andChampia would likely be much less common. This study also highlights the importance of using DNA analysis of voucher specimens in monitoring programs to accurately identify cryptic invaders.  相似文献   

Spatial moments for colloid-enhanced radionuclide transport in heterogeneous aquifers     

Gerardo Severino  Vladimir Cvetkovic  Antonio Coppola 《Advances in water resources》2007

We consider colloid facilitated radionuclide transport by steady groundwater flow in a heterogeneous porous formation. Radionuclide binding on colloids and soil-matrix is assumed to be kinetically/equilibrium controlled. All reactive parameters are regarded as uniform, whereas the hydraulic log-conductivity is modelled as a stationary random space function (RSF). Colloid-enhanced radionuclide transport is studied by means of spatial moments pertaining to both the dissolved and colloid-bounded concentration. The general expressions of spatial moments for a colloid-bounded plume are presented for the first time, and are discussed in order to show the combined impact of sorption processes as well as aquifer heterogeneity upon the plume migration. For the general case, spatial moments are defined by the aid of two characteristic reaction functions which cannot be expressed analytically. By adopting the approximation for the longitudinal fluid trajectory covariance valid for a flow parallel to the formation bedding suggested by Dagan and Cvetkovic [Dagan G, Cvetkovic V. Spatial Moments of Kinetically Sorbing Plume in a Heterogeneous Aquifers. Water Resour Res 1993;29:4053], we obtain closed form solutions.  相似文献   

Geochemical pattern classification of recent volcanic products from Mt. Etna, Italy, based on Kohonen maps and fuzzy clustering     

Rosa Anna Corsaro  Susanna Falsaperla  Horst Langer 《International Journal of Earth Sciences》2013,102(4):1151-1164

We present the application of a classification method based on Kohonen maps and fuzzy clustering to geochemical analyses of volcanic products erupted on Mt. Etna from 1995 to 2005. Based on 13 major and trace elements, the classification allows a new way to visualize distinct compositional features of magma both considering long period as well as single eruptive events, such as in 2001 and 2002–03 flank eruptions. Products of the various vents do not necessarily form homogeneous groups, but show clear trends of chemical evolution with time. Using a convenient color code, the graphical visualization of the results in just a single picture allows the rapid identification of the compositional features of each sample and their comparison with all the products analyzed in the 10-year-long time span. This single picture accounts for the mutual interactions of the 13 components avoiding shortcomings of classical low-dimensional plots where components relevant for the discrimination have to be found in a priori study of many diagrams. On the basis of the synoptic information provided by pattern classification, we identify links between the products of different eruptive vents which deliver a reliable picture of a multifaceted plumbing system, in agreement with geochemical and geophysical evidence reported in literature. The analysis of the 13-dimensional data set using the Kohonen maps and fuzzy clustering simultaneously turned out to be straightforward and easy. Accordingly, the results of this application will be useful also as a contextual data set for new data in future ongoing eruptive episodes.  相似文献   

Adhesion and collisional release of particles in dense planetary rings     

Anna Bodrova  Jürgen Schmidt  Frank Spahn  Nikolay Brilliantov 《Icarus》2012,218(1):60-68

We propose a simple theoretical model for aggregative and fragmentative collisions in Saturn’s dense rings. In this model the ring matter consists of a bimodal size distribution: large (meter sized) boulders and a population of smaller particles (tens of centimeters down to dust). The small particles can adhesively stick to the boulders and can be released as debris in binary collisions of their carriers. To quantify the adhesion force we use the JKR theory (Johnson, K., Kendall, K., Roberts, A. [1971]. Proc. R. Soc. Lond. A 324, 301–313). The rates of release and adsorption of particles are calculated, depending on material parameters, sizes, and plausible velocity dispersions of carriers and debris particles. In steady state we obtain an expression for the amount of free debris relative to the fraction still attached to the carriers. In terms of this conceptually simple model a paucity of subcentimeter particles in Saturn’s rings (French, R.G., Nicholson, P.D. [2000]. Icarus 145, 502–523; Marouf, E. et al. [2008]. Abstracts for “Saturn after Cassini–Huygens” Symposium, Imperial College London, UK, July 28 to August 1, p. 113) can be understood as a consequence of the increasing strength of adhesion (relative to inertial forces) for decreasing particle size. In this case particles smaller than a certain critical radius remain tightly attached to the surfaces of larger boulders, even when the boulders collide at their typical speed. Furthermore, we find that already a mildly increased velocity dispersion of the carrier-particles may significantly enhance the fraction of free debris particles, in this way increasing the optical depth of the system.  相似文献   

Rapid characterisation of the extremely large landslide threatening the Rules Reservoir (Southern Spain)     

Reyes-Carmona  Cristina  Galve  Jorge Pedro  Moreno-Sánchez  Marcos  Riquelme  Adrián  Ruano  Patricia  Millares  Agustín  Teixidó  Teresa  Sarro  Roberto  Pérez-Peña  José Vicente  Barra  Anna  Ezquerro  Pablo  López-Vinielles  Juan  Béjar-Pizarro  Marta  Azañón  José Miguel  Monserrat  Oriol  Mateos  Rosa María 《Landslides》2021,18(12):3781-3798

Landslides - When an active landslide is first identified in an artificial reservoir, a comprehensive study has to be quickly conducted to analyse the possible hazard that it may represent to such...  相似文献   

From Jurassic rifting to Cretaceous subduction in NW Iranian Azerbaijan: geochronological and geochemical signals from granitoids     

Anna?LechmannEmail authorView author&#;s OrcID profile  Jean-Pierre?Burg  Peter?Ulmer  Ali?Mohammadi  Marcel?Guillong  Mohammad?Faridi 《Contributions to Mineralogy and Petrology》2018,173(12):102

Previous interpretations of a Jurassic subduction in Iran were based on trace element classification diagrams for granitoids, but their reliability is questionable, underscored by modern examples of continental break-up zones such as the Baja California. We present new field observations, bulk rock geochemistry, Sr and Nd isotope analyses and U–Pb zircon geochronology to assess the age and tectonic setting of previously undated intermediate to felsic magmatic rocks cropping out in the Precambrian basement of NW Iranian Azerbaijan. The geochronology revealed an uneven distribution in space and time: Late Jurassic (159–154 Ma) intrusions and dikes are alkaline to calc-alkaline. Their melt source is mantle dominated with a distinct continental contribution disclosed by radiogenic isotopes and abundant inherited zircon cores. Mid-Cretaceous (112–96 Ma) plutonic bodies and associated volcanic rocks occur only to the east of the major Siah Cheshmeh–Khoy Fault. They have geochemical signatures typical of a metasomatized mantle. In consistence with the sedimentation history of the area, our new interpretation attributes the Late Jurassic magmatism to thinning of a continental lithosphere in a rift-related setting. Mid-Cretaceous magmatism was produced by oceanic subduction beneath the Central Iran continent. We interpret the 40-Ma age gap between the two magmatic episodes as the time of opening of the oceanic basin witnessed by the Khoy ophiolite in the study area.  相似文献