117,962 research outputs found
Ranking hubs and authorities using matrix functions
No full textThe notions of subgraph centrality and communicability, based on the exponential of the adjacency matrix of the underlying graph, have been effectively used in the analysis of undirected networks. In this paper we propose an extension of these measures to directed networks, and we apply them to the problem of ranking hubs and authorities. The extension is achieved by bipartization, i.e., the directed network is mapped onto a bipartite undirected network with twice as many nodes in order to obtain a network with a symmetric adjacency matrix. We explicitly determine the exponential of this adjacency matrix in terms of the adjacency matrix of the original, directed network, and we give an interpretation of centrality and communicability in this new context, leading to a technique for ranking hubs and authorities. The matrix exponential method for computing hubs and authorities is compared to the well known HITS algorithm, both on small artificial examples and on more realistic real-world networks. A few other ranking algorithms are also discussed and compared with our technique. The use of Gaussian quadrature rules for calculating hub and authority scores is discussed
Nanoparticles Based on Fructose and Alkaly-Earth Halogenides with Second Harmonic Generation properties for applications as bio-sensors and for Radiotherapy
No full textIn recent years, some Metal Organic Frameworks with Second Harmonic Generation (SHG) properties, based on fructose and alkali-earth alogenides, were investigated to understand the effect of cation size and anion polarizability on crucial quantities correlated to the non-linear optical (NLO) response, such as hyperpolarizability and optical susceptibility [1,2]. The compounds studied are interesting for biomedicine applications, as they combine high biocompatibility, due to their non-toxic components, and significant SH emission, that can permit exploitation for in vitro bio-imaging.
Right now, a possible application in radiotherapy is under investigation. To these purposes we synthetized nanoparticles of some MOFs, based on fructose and SrX2 salts (X=Cl, I). The compounds were characterized by single-crystal and powder XRD, IR and RAMAN spectroscopy and the second-order susceptibility were estimated from theoretical calculations, both in vacuo and in the solid state. Furthermore, we attempted to assess the reduction of the SH intensity for small quantities of nano-crystals, in order to ascertain the possibility of applications in biological systems.
The nanoparticles were encapsulated in a phospholipidic shell and preliminary activity studies on target cells are in progress.
[1] D. Marabello, P. Antoniotti, P. Benzi, C. Canepa, E. Diana, L. Operti, L. Mortati, M. P. Sassi J. Mater.
Sci., 2015, 50 (12), 4330- 4341
[2] D. Marabello, P. Antoniotti, P. Benzi, C. Canepa, L. Mortati, M. P. Sassi Acta Cryst. B, accepte
Action of L-acetylcarnitine on age-dependent modifications of mitochondrial membrane proteins from rat cerebellum
No full textProtein patterns of mitochondrial outer membrane, inner membrane, and matrix from non-synaptic (free) mitochondria from rat cerebellum at different ages (4, 8, 12, 16, 20, and 24 months) were analyzed by gel electrophoresis. Acute L-acetylcarnitine treatment was performed by a single i.p. injection (100 mg/kg body weight) of the substance 60 min before the sacrifice of the animals. Different age-dependent changes were obtained for the proteins of the three fractions. The amount of some protein subunits increased and/or decreased after drug treatment. In particular, protein composition of the inner mitochondrial membrane showed significant age-related modifications. This result probably indicates differences in protein synthesis and/or turnover rates in the various mitochondrial compartments during aging. Acute L-acetylcarnitine treatment caused: a high increase in the amount of one inner membrane protein with Mw 16 kDa, at all the ages studied; a decrease in the amount of many other inner membrane proteins; modifications of some matrix proteins. Our results show that in vivo administration of L-acetylcarnitine affects mainly the inner membrane protein composition of cerebellar mitochondri
Homogeneous and Isotropic Turbulence: A Short Survey on Recent Developments
No full textWe present a detailed review of some of the most recent developments on Eulerian and Lagrangian turbulence in homogeneous and isotropic statistics. In particular, we review phenomenological and numerical results concerning the issue of universality with respect to the large scale forcing and the viscous dissipative physics. We discuss the state-of-the-art of numerical versus experimental comparisons and we discuss the dicotomy between phenomenology based on coherent structures or on statistical approaches. A detailed discussion of finite Reynolds effects is also presented
Solution of linear systems from an optimal control problem arising in wind simulation
No full textSeveral solution strategies for a class of large, sparse linear systems with a block 2 × 2 structure arising from the finite element discretization of an optimal control problem in wind simulation are introduced and analyzed. Block preconditioners and a sparse direct solver on the original coupled system are compared with a preconditioned GMRES iteration applied to a reduced system (Schur complement). Theoretical and experimental results demonstrate the effectiveness of the reduced system approach. Copyright © 2009 John Wiley & Sons, Ltd
Giorgio De Chirico e la nascita della metafisica. l’"altra" avanguardia italiana 1910-1911
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Il ritrovato affresco di Bartolomeo De Benzi da Torno
No full textIl saggio descrive e attribuisce al pittore lariano Bartolomeo De Benzi un affresco rinascimentale venuto alla luce durante la campagna di restauro della chiesa agostiniana di Santa Maria delle Grazie di Gravedona (CO)
Figures 7A-L in Six new species and new records of the genus Desmopachria Babington (Coleoptera: Dytiscidae: Hyphidrini) from Brazil and redescription of D. varians Wehncke, 1877
No full textFigures 7A-L. Desmopachria varians. (A) Dorsal View. (B) Ventral view. (C) Colour pattern of Elytron. (D) Apical ventrite. (E-M) Male genitalia. (E) Dorsal view. (F) Ventral view. (G) Lateral view. (H) Coverslip dorsal view. (I) Lateral lobe dorsal view. (J) Median lobe dorsal view. (K) Median lobe lateral view. (L) Lateral lobe lateral view. Figs. 1A-D scale bars = 1 mm, Figs. 1E-L scale bars = 0.1 mm.Published as part of Braga, Rafael Benzi, 2018, Six new species and new records of the genus Desmopachria Babington (Coleoptera: Dytiscidae: Hyphidrini) from Brazil and redescription of D. varians Wehncke, 1877, pp. 1-15 in Papéis Avulsos de Zoologia 58 on page 13, DOI: 10.11606/1807-0205/2018.58.41, http://zenodo.org/record/523545
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