A model for multifragmentation in heavy-ion reactions

From an experimental point of view, clear signatures of multifragmentation have been detected by different experiments. On the other hand, from a theoretical point of view, many different models, built on the basis of totally different and often even contrasting assumptions, have been provided to explain them. In this contribution we show the capabilities and the shortcomings of one of this models, a QMD code developed by us and coupled to the nuclear de-excitation module taken from the multipurpose transport and interaction code FLUKA, in reproducing the multifragmentation observations recently reported by the INDRA collaboration for the reaction Nb + Mg at a 30 MeV/A projectile bombarding energy. As far as fragment production is concerned, we also briefly discuss the isoscaling technique by considering reactions characterized by a different isospin asymmetry, and we explain how the QMD + FLUKA model can be applied to obtain information on the slope of isotopic yield ratios, which is crucially related to the symmetry energy of asymmetric nuclear matter.Comment: 8 pages, 2 figures, Proc. 12th International Conference on Nuclear Reaction Mechanisms, Varenna, Italy, June 15 - 19 200

Analogue Gravity and ultrashort laser pulse filamentation

Ultrashort laser pulse filaments in dispersive nonlinear Kerr media induce a moving refractive index perturbation which modifies the space-time geometry as seen by co-propagating light rays. We study the analogue geometry induced by the filament and show that one of the most evident features of filamentation, namely conical emission, may be precisely reconstructed from the geodesics. We highlight the existence of favorable conditions for the study of analogue black hole kinematics and Hawking type radiation.Comment: 4 pages, revised versio

Frizzled receptor 6 marks rare, highly tumourigenic stem-like cells in mouse and human neuroblastomas

Copyright © 2011 Cantilena et al. This is an open-access article distributed under the terms of the Creative Commons Attribution 3.0 License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The article was made available through the Brunel Open Access Publishing Fund.Wnt signalling is an important component of vertebrate development, required for specification of the neural crest. Ten Wnt receptors [Frizzled receptor 1-10 (Fzd1-10)] have been identified so far, some of which are expressed in the developing nervous system and the neural crest. Here we show that expression of one such receptors, Fzd6, predicts poor survival in neuroblastoma patients and marks rare, HIF1/2 α-positive cells in tumour hypoxic areas. Fzd6 positive neuroblastoma cells form neurospheres with high efficiency, are resistant to doxorubicin killing and express high levels of mesenchymal markers such as Twist1 and Notch1. Expression of Fzd6 is required for the expression of genes of the noncanonical Wnt pathway and the spheres forming activity. When transplanted into immunodeficient mice, neuroblastoma cells expressing the Fzd6 marker grow more aggressively than their Fzd6 negative counterparts. We conclude that Fzd6 is a new surface marker of aggressive neuroblastoma cells with stem cell-like features.This work was sponsored by the Wellcome Trust, the RICC cancer fund, SPARKS, the Italian Association for Cancer Research, Regione Liguria and the Italian Ministry of Health

Bimagnon studies in cuprates with Resonant Inelastic X-ray Scattering at the O K edge. II - The doping effect in La2-xSrxCuO4

We present RIXS data at O K edge from La2-xSrxCuO4 vs. doping between x=0.10 and x=0.22 with attention to the magnetic excitations in the Mid-Infrared region. The sampling done by RIXS is the same as in the undoped cuprates provided the excitation is at the first pre-peak induced by doping. Note that this excitation energy is about 1.5 eV lower than that needed to see bimagnons in the parent compound. This approach allows the study of the upper region of the bimagnon continuum around 450 meV within about one third of the Brilluoin Zone around \Gamma. The results show the presence of damped bimagnons and of higher even order spin excitations with almost constant spectral weight at all the dopings explored here. The implications on high Tc studies are briefly addressed

Research findings and decision making: the case of renewable energy

Background Energy policies from local to global scale are increasingly questioned in terms of sustainability. Evidence- and science-based decision making in this field needs a robust and transparent integrated assessment of policy options. Nevertheless, scientific findings do not lead straight to political conclusions, and the relationship between science and decision making is a debated issue. The article discusses the main barriers to effective interaction and communication between scientific enquiry and decision making and proposes some effective ways to overcome these barriers, starting from experiences in the biomass energy sector

Free-carrier screening of polarization fields in wurtzite GaN/InGaN laser structures

The free-carrier screening of macroscopic polarization fields in wurtzite GaN/InGaN quantum wells lasers is investigated via a self-consistent tight-binding approach. We show that the high carrier concentrations found experimentally in nitride laser structures effectively screen the built-in spontaneous and piezoelectric polarization fields, thus inducing a ``field-free'' band profile. Our results explain some heretofore puzzling experimental data on nitride lasers, such as the unusually high lasing excitation thresholds and emission blue-shifts for increasing excitation levels.Comment: RevTeX 4 pages, 4 figure

One year follow-up of a randomized trial with a dilemma-focused intervention for depression: Exploring an alternative to problem-oriented strategies

© 2018 Feixas et al.Cognitive behavioural therapy (CBT) is aimed to counteract cognitions and behaviours that are considered as dysfunctional. The aim of the study is to test whether the inclusion of a non-counteractive approach (dilemma-focused intervention, DFI) in combination with CBT group therapy will yield better short- and long-term outcomes than an intervention conducted entirely using CBT.Peer reviewedFinal Published versio

Longitudinal coherence in thermal ghost imaging

We show theoretically and experimentally that lensless ghost imaging with thermal light is fully interpretable in terms of classical statistical optics. The disappearance of the ghost image when the object and the reference planes are located at different distances from the source is due to the fading out of the intensity-intensity cross correlation between the two planes. Thus the visibility and the resolution of the ghost image are determined by the longitudinal coherence of the speckle beam, and no quantum explanation is necessary.We show theoretically and experimentally that lensless ghost imaging with thermal light is fully interpretable in terms of classical statistical optics. The disappearance of the ghost image when the object and the reference planes are located at different distances from the source is due to the fading out of the intensity-intensity cross correlation between the two planes. Thus the visibility and the resolution of the ghost image are determined by the longitudinal coherence of the speckle beam, and no quantum explanation is necessary. \ua9 2008 American Institute of Physics

The physics models of FLUKA: status and recent development

A description of the intermediate and high energy hadronic interaction models used in the FLUKA code is given. Benchmarking against experimental data is also reported in order to validate the model performances. Finally the most recent developments and perspectives for nucleus-nucleus interactions are described together with some comparisons with experimental data.Comment: talk from the 2003 Computing in High Energy and Nuclear Physics (CHEP03), La Jolla, Ca, USA, March 2003, 10 pages, p