Connected operators for sprite creation and layered representation of image sequences

This paper proposes and discusses the use of motion-oriented connected operators for sprite creation. Motion-oriented connected operators are tools allowing the simplification of frames by removing objects that do not follow a given motion. They combine features of filtering and segmentation tools. They are, however, less computationally expensive than most motion-oriented segmentation algorithms. In this paper, we show how they can be used to efficiently remove outliers with respect to the dominant motion and to create layered representation of sequences.Peer ReviewedPostprint (published version

Anatomy of three-body decay II. Decay mechanism and resonance structure

We use the hyperspherical adiabatic expansion method to discuss the the two mechanisms of sequential and direct three-body decay. Both short-range and Coulomb interactions are included. Resonances are assumed initially populated by a process independent of the subsequent decay. The lowest adiabatic potentials describe the resonances rather accurately at distances smaller than the outer turning point of the confining barrier. We illustrate with realistic examples of nuclei from neutron ($^{6}$He) and proton ($^{17}$Ne) driplines as well as excited states of beta-stable nuclei ($^{12}$C).Comment: To be published in Nuclear Physics

Geiger-Mode Avalanche Photodiodes in Particle Detection

It is well known that avalanche photodiodes operated in the Geiger mode above the breakdown voltage offer a virtually infinite sensitivity and time accuracy in the picosecond range that can be used for single photon detection. However, their performance in particle detection remains still unexplored. In this contribution, we are going to expose the different steps that we have taken in order to prove the efficiency of Geiger mode avalanche photodiodes in the aforementioned field. In particular, we will present an array of pixels of 1mmx1mm fabricated with a standard CMOS technology for characterization in a test beam.Comment: 7 pages, 2 figures, Proceedings of LCWS1

Decay of low-lying 12C resonances within a 3alpha cluster model

We compute energy distributions of three $\alpha$-particles emerging from the decay of $^{12}$C resonances by means of the hyperspherical adiabatic expansion method combined with complex scaling. The large distance continuum properties of the wave functions are crucial and must be accurately calculated. The substantial changes from small to large distances determine the decay mechanisms. We illustrate by computing the energy distributions from decays of the $1^{+}$ and $3^-$-resonances in $^{12}$C. These states are dominated by direct and sequential decays into the three-body continuum respectively.Comment: 5 pages, 3 figures. Proceedings of the Clusters '07 conference held in Stratford-upon-Avon in September 200

Bottom-up creativity and insurgent citizenship in “Afro Lisboa”: Racial difference and cultural commodification in Portugal

This article analyzes recent audio-visual creativity by young Afrodescendants emerging out of the outskirts of Lisbon. We argue that those cultural productions are challenging unproblematic identifications of the Portuguese capital as a multicultural city shaped by African communities. Responding to issues of racism, police violence, and urban marginalization, but also to celebratory views of Portuguese society as exempt of racial discrimination, the communities inhabiting the neighborhoods of Cova da Moura and Quinta do Mocho are employing creative means to develop a positive identification of afro-diasporic communities. Engaging those means, this article places bottom-up creativity side by side to the activity of Lisbon cultural institutions such as museums and contemporary art centers. It also addresses the relevance of visual and musical creativity to counter the stereotypes and images frequently used to categorize racialized subjects and communities in Portugal. Finally, it explores the strategies employed by the residents of the above mentioned neighborhoods to struggle against the process of cultural gentrification Lisbon is going through.info:eu-repo/semantics/acceptedVersio

GIRAFFE multiple integral field units at VLT: a unique tool to recover velocity fields of distant galaxies

The GIRAFFE spectrograph is unique in providing the integral field spectroscopy of fifteen distant galaxies at the same time. It has been successfully implemented at the second VLT unit within the FLAMES facility. We present GIRAFFE observations acquired during the Guaranteed Time Observation of the Paris Observatory, using total exposure times ranging from 6 to 12 hours. The reduced 3D cube of each galaxy has been deconvolved using our new package DisGal3D. This software has been written using the only assumption that UV light traces the emission line regions. The comparison between GIRAFFE spectra and HST imagery allows us to recover details on velocity fields as small as 0.3-0.4 arcsec. It has been successfully tested using Fabry Perot observations of nearby galaxies purposely redshifted to large distances. We present here preliminary results for three distant galaxies at 0.45< z < 0.65, whose velocity fields have been derived with exquisite spectral (R=10000) and spatial resolutions. Observed velocity fields range from disturbed fields expected in major merger events to those of regular spiral with minor perturbations. For the latter, one could accurately derive the dynamical major axis and the maximal rotational velocity. We conclude that dynamical properties of a large number of distant galaxies can be routinely derived at VLT. This opens a new avenue towards the understanding of the galaxy formation and evolution during the last 8 Gyr.Comment: 4 pages, 3 jpeg figures. to appear in A&