BVRcIc photometric evolution and flickering during the 2010 outburst of the recurrent nova U Scorpii

CCD BVRcIc photometric observations of the 2010 outburst of the recurrent nova U Scorpii are presented. The light-curve has a smooth development characterized by t2(V)=1.8 and t3(V)=4.1 days, close to the t2(V)=2.2 and t3(V)=4.3 days of 1999 outburst. The plateau phase in 2010 has been brighter, lasting shorter and beginning earlier than in the 1999 outburst. Flickering, with an amplitude twice larger in $I_{\rm C}$ than in $B$ band, was absent on day +4.8 and +15.7, and present on day +11.8, with a time scale of about half an hour.Comment: published March 1

Localized Manifold Harmonics for Spectral Shape Analysis

The use of Laplacian eigenfunctions is ubiquitous in a wide range of computer graphics and geometry processing applications. In particular, Laplacian eigenbases allow generalizing the classical Fourier analysis to manifolds. A key drawback of such bases is their inherently global nature, as the Laplacian eigenfunctions carry geometric and topological structure of the entire manifold. In this paper, we introduce a new framework for local spectral shape analysis. We show how to efficiently construct localized orthogonal bases by solving an optimization problem that in turn can be posed as the eigendecomposition of a new operator obtained by a modification of the standard Laplacian. We study the theoretical and computational aspects of the proposed framework and showcase our new construction on the classical problems of shape approximation and correspondence. We obtain significant improvement compared to classical Laplacian eigenbases as well as other alternatives for constructing localized bases

ACOUSTIC RANGE IMAGE SEGMENTATION BY EFFECTIVE MEAN SHIFT

Image perception in underwater environment is a difficult task for a human operator, and data segmentation becomes a crucial step toward an higher level interpretation and recognition of the observing scenarios. This paper contributes to the related state of the art, by fitting the mean shift clustering paradigm to the segmentation of acoustical range images, providing a segmentation approach in which whatever parameter tuning is absent. Moreover, the method exploits actively the connectivity information provided by the range map, by using reverse projection as acceleration technique. Therefore, the method is able to produce, starting from raw range data, meaningful segmented clouds of points in a fully automatic and efficient fashion. 1

N=2 Supergravity Lagrangian Coupled to Tensor Multiplets with Electric and Magnetic Fluxes

We derive the full N=2 supergravity Lagrangian which contains a symplectic invariant scalar potential in terms of electric and magnetic charges. As shown in reference [1], the appearance of magnetic charges is allowed only if tensor multiplets are present and a suitable Fayet-Iliopoulos term is included in the fermion transformation laws. We generalize the procedure in the quoted reference by adding further a Fayet-Iliopoulos term which allows the introduction of electric charges in such a way that the potential and the equations of motion of the theory are symplectic invariant. The theory is further generalized to include an ordinary electric gauging and the form of the resulting scalar potential is given.Comment: 1+34 pages LaTeX, correction of a typo in the ungauged scalar potentia