6,612 research outputs found
A uniqueness result for the continuity equation in two dimensions
No full textWe characterize the autonomous, divergence-free vector fields on the plane such that the Cauchy problem for the continuity equation admits a unique bounded solution (in the weak sense) for every bounded initial datum; the characterization is given in terms of a property of Sard type for the potential associated to .
As a corollary we obtain uniqueness under the assumption that the curl of is a measure. This result can be extended to certain non- autonomous vector fields with bounded divergence
On the Lp-differentiability of certain classes of functions
No full textWe prove the -differentiability at almost every point for convolution products on of the form , where is bounded measure and is a homogeneous kernel of degree .
From this result we derive the -differentiability for vector fields on whose curl and divergence are measures, and also for vector fields with bounded deformation
Structure of level sets and Sard-type properties of Lipschitz maps
No full textWe consider certain properties of maps of class C2 from Rd to Rd−1 that are strictly related to Sard’s theorem, and we show that some of them can be extended to Lipschitz maps, while others require some additional regularity. We also give examples showing that, in terms of regularity, our results are optimal
Crustal xenoliths from Tallante (Betic Cordillera, Spain): insights for an interlayered crust-mantle boundary?
No full textThe geology of the Betic area has been characterized by several tectono-magmatic episodes related to multiple orogenic cycles and extensional phases (Puga et al., 2011; Bianchini et al., 2011 and references therein) ultimately leading to widespread subduction-related and anorogenic volcanism. The last magmatic phase (Pliocene) is represented by Na-alkaline basalts at Tallante that entrained and exhumed abundant deep-seated xenoliths of both mantle and crustal provenance. These xenoliths attracted an intense petrological interest testified by an impressive number of scientific papers. Unfortunately, most of these studies focused on the ultramafic xenoliths ignoring the crustal lithologies that were investigated only by the paper of Vielzeuf (1983).
In this contribution we present new data on felsic (i.e. crustal) xenoliths from Tallante that integrate the petrological information provided by the ultramafic parageneses, highlighting the deep lithosphere stratigraphy of the area as well as constraints for the interpretation of geophysical data and models.
The felsic xenolith is characterized by a metamorphic peak assemblage composed of quartz + spinel + sillimanite. The occurrence of cordierite rims between spinel and quartz is related to post-peak metamorphism. To obtain P-T information from this texture, we calculated a P-T pseudosection for the specific mineral reaction texture spinel + quartz = cordierite. The microbulk composition was modeled in the SiO2-Al2O3-FeO-Fe2O3-MgO system. Water has not been taken into account in order to simulate the likely anhydrous conditions occurring during the peak metamorphic stage.
The observed paragenesis Spinel-Quartz-Sillimanite indicates temperature around 1000 °C for pressure of 7 kbar, increasing to 1125 °C at 9 kbar. The formation of cordierite rims between quartz and spinel requires, in the chosen system, decompression down to < 6 kbar (T < 950 °C). This evolution was accompanied by partial melting testified by glasses films and blebs.
Therefore, felsic xenoliths from Tallante attained P-T condition overlapping those recorded by the ultramafic xenoliths of mantle provenance that are represented by spinel-plagioclase peridotite.
This suggests that an intimate association of crust and mantle lithologies with pervasive interlayering and interfingering at metric to hectometric scale, plausibly not detectable by geophysical approaches, characterizes the Moho discontinuity in this area.
Melting preferentially occurred in the crustal domains (characterized by lower solidus conditions) generating silica-rich magmas that veined the surrounding peridotite domains, also inducing orthopyroxene-rich metasomatic aureole.
The proposed petrological scenario is discussed taking also into account the investigations on the neighboring massifs of Ronda and Beni Bousera where the fossil crust-mantle boundary is exposed, providing fresh insights for the configuration and evolution of the Moho discontinuity in collisioned plate boundaries, that are widespread throughout the peri-Mediterranean realm.
The hypotized eteropic crust-mantle boundary would represent a suitable source region for exotic magma types such as lamproites that are common within the Mediterranean area (Tommasini et al. 2011).
References
- Bianchini et al., 2011. Lithos 124, 308-318.
- Puga et al., 2011. Lithos 124, 255-272.
- Tommasini et al. Earth Planet. Sci. Lett. 301, 469-478.
- Vielzeuf, 1983. Contrib. Mineral. Petrol. 82, 301-31
Per un inventario dei carteggi bianchiniani
No full textricognizione dei materiali epistolari manoscritti e a stampa relativi all'erudito veronese Francesco Bianchini (1662-1729
V. Gazzola Stacchini, G. Bianchini : Le accademie dell'Aretino nel XVII e XVIII secolo, 1978. (Coll. «Archivium Romanicum », 14, série 1)
No full textGeorgelin Jean. V. Gazzola Stacchini, G. Bianchini : Le accademie dell'Aretino nel XVII e XVIII secolo, 1978. (Coll. «Archivium Romanicum », 14, série 1). In: Dix-huitième Siècle, n°13, 1981. Juifs et judaïsme. p. 491
V. Gazzola Stacchini, G. Bianchini : Le accademie dell'Aretino nel XVII e XVIII secolo, 1978. (Coll. «Archivium Romanicum », 14, série 1)
No full textGeorgelin Jean. V. Gazzola Stacchini, G. Bianchini : Le accademie dell'Aretino nel XVII e XVIII secolo, 1978. (Coll. «Archivium Romanicum », 14, série 1). In: Dix-huitième Siècle, n°13, 1981. Juifs et judaïsme. p. 491
An overdetermined problem for the anisotropic capacity
No full textWe consider an overdetermined problem for the Finsler Laplacian in the exterior of a convex domain in RN, establishing a symmetry result for the anisotropic capacitary potential. Our result extends the one of Reichel (Arch Ration Mech Anal 137(4):381–394, 1997), where the usual Newtonian capacity is considered, giving rise to an overdetermined problem for the standard Laplace equation. Here, we replace the usual Euclidean norm of the gradient with an arbitrary norm H. The resulting symmetry of the solution is that of the so-called Wulff shape (a ball in the dual norm H0)
EUROPE AND THE BALKANS INTERNATIONAL NETWORK. A Series of Balkan and East European Studies
No full textThe Series - that has published so far 35 volumes - is peer-review based and publish monographic and collective studies mainly in English, occasionally in Franch and Italian. The selected studies deal mainly on the Balkans and Eastern Europe in general with a focus on nationalism, gender, religions, peace-keeping and international relations, regional economic development, history and memory, law.
During 2012 the Series has published a book on the idependence of Kosovo co-edited by a Serb and a Kosovar authors and another one is going to be published by the end of teh year on Civic and uncivic values in Bosnia-Herzegovina.
Moreover, the Series mirrors research and studies promoted by the members of the "International Network Europe and the Balkans", coordinated by the University of Bologna. Established at the end of 1993 with the financial support of the European Commission (Human Capital and Mobility Programme), the Network relies on the collaboration of some of the best known European and North-American scholars. The initiative was conceived as a University project, aiming to make academic research more relevant to the widespread need for information.
The selected volumes for publications are peer-reviewed by the members of the Network.
The catalogue is available for information at the web page of Longo www.longo-editore.it as well as at the web page of the Network www.eurobalk.net.
The catalogue is also distributed regularly through the Newsletter of the Network to 13.000 addresses every two months
The Series is based on an international Scientific Board as follows:
S. Bianchini (U. of Bologna), G. Schoepflin (SSEES, London); A. Krasteva (New Bulgarian University, Sofia),; D. Janjic (Institute of Social Sciences, Belgrade); A. Jaz'kova (Russian Academy of Sciences, Moscow); C. Nation (US Army War College, Carlisle, Pennsylvania); Z. Puhovski (University of Zagreb); R. Rizman (U. of Ljubljana); P. Shoup (emeritus, U. of Virginia); M. Uvalic (U. of Perugia)
LMW-heparins (5 KD) and Oligo-heparins (2 KD) produced by gel-permeation enrichment or radical process: comparison of structures, physico-chemical and biological properties.
No full textA process of chemical depolymerization of heparin initiated by free radicals has been developed. The process follows reaction kinetics of apparent first order, and it is possible to obtain heparins with different molecular weights. Low and very low molecular weight heparins (LMWHs, approximately 5 kDa, and Oligo-H, approximately 2 kDa) have been prepared by enriching fractions derived from natural heparin by gel permeation. The LMWHs produced by a radical reaction have been characterized by their physicochemical properties, patterns of constitutive disaccharides, NMR spectra, and biological activities in comparison with those of the LMWHs produced by an enrichment process. The process of free radical degradation is shown to produce heparins with a desired molecular weight (from 1 to greater than 10 kDa) without changes in their primary structure and in their physicochemical properties and with the in vitro biological activities expected for LMWHs. Furthermore, the limits of enzymatic cleavage of heparins with different molecular weights by heparinases and the possibility of obtaining a precise pattern of constitutive disaccharides are discussed
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