14,282 research outputs found

    Controlling chaos in diluted networks with continuous neurons

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    Diluted neural networks with continuous neurons and nonmonotonic transfer function are studied, with both fixed and dynamic synapses. A noisy stimulus with periodic variance results in a mechanism for controlling chaos in neural systems with fixed synapses: a proper amount of external perturbation forces the system to behave periodically with the same period as the stimulus.Comment: 11 pages, 8 figure

    Campañas medioambientales contra empresas forestales: ¿Cuál es el objetivo de estas campañas?

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    Campaigns by environmental non-governmental organisations (ENGOs) can have far reaching consequences in determining the policies of governments and corporations. This paper examines campaigns targeting forestry companies to determine what makes a successful campaign. Over forty ENGOs completed a questionnaire defining what they perceive to constitute a successful campaign. The responses were analysed using Analytical Hierarchy Process. The results showed that campaigns by ENGOs have two main targets: changes in laws and the target group implementing the campaign’s recommendation(s). Achieving these targets, for most, constitute a successful campaign. Subsequently, representatives of seven ENGOs were questioned to attain their perspectives of the results in comparison to campaigns they are conducting against forest enterprises. They supported the results of the questionnaire, but also felt that there are various other factors that need to be considered (e.g. the campaign’s timeframe and the possibility of having hidden targets) that increase the issue’s complexity.Campañas llevadas a cabo por organizaciones no gubernamentales ambientalistas (ONGsA) pueden tener importantes consecuencias a la hora de influenciar las políticas tanto de gobiernos como de corporaciones industriales. Este artículo se centra en el estudio de campañas cuyo blanco son las empresas madereras, analizando que condiciones deben cumplir dichas campañas para poder ser consideradas como exitosas. Para ello, más de cuarenta ONGsA rellenaron un cuestionario en el que se les pedía que indicaran su opinión sobre que define una campaña exitosa. Las respuestas fueron analizadas utilizando un Proceso Analítico Jerárquico (AHP). Los resultados mostraron que las campañas de las ONGsA tienen dos objetivos principales, obtener cambios en las leyes y que la compañía o gobierno objetivo de la campaña cumpla las recomendaciones propuestas. A posteriori, los representantes de siete ONGsA, con campañas ambientales en curso contra empresas madereras, fueron preguntados sobre si los resultados obtenidos a través del análisis AHP estaban en concordancia con las perspectivas para sus campañas ambientales. Como resultado, se obtuvo que si bien sus perspectivas coincidían con los resultados del análisis, existen otros factores a tener en cuenta (por ejemplo el marco temporal de la campaña y la posibilidad de afectar objetivos no explícitamente señalados) que aumentan la complejidad del problema

    C/O white dwarfs of very low mass: 0.33-0.5 Mo

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    The standard lower limit for the mass of white dwarfs (WDs) with a C/O core is roughly 0.5 Mo. In the present work we investigated the possibility to form C/O WDs with mass as low as 0.33 Mo. Both the pre-WD and the cooling evolution of such nonstandard models will be described.Comment: Submitted to the "Proceedings of the 16th European White Dwarf Workshop" (to be published JPCS). 7 pages including 13 figure

    Review of the ELI-NP-GBS low level rf and synchronization systems

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    The Gamma Beam System (GBS) of ELI-NP is a linac based gamma-source in construction at Magurele (RO) by the European consortium EuroGammaS led by INFN. Photons with tunable energy and with intensity and brilliance well beyond the state of the art will be produced by Compton back-scattering between a high quality electron beam (up to 740 MeV) and a 515 nm intense laser pulse. Production of very intense photon flux with narrow bandwidth requires multi-bunch operation at 100 Hz repetition rate. A total of 13 klystrons, 3 S-band (2856 MHz) and 10 C-band (5712 MHz) will power a total of 14 Travelling Wave accelerating sections (2 S-band and 12 C-band) plus 3 S-band Standing Wave cavities (a 1.6 cell RF gun and 2 RF deflectors). Each klystron is individually driven by a temperature stabilized LLRF module, for a maximum flexibility in terms of accelerating gradient, arbitrary pulse shaping (e.g. to compensate beam loading effects in multi-bunch regime) and compensation of long-term thermal drifts. In this paper, the whole LLRF system architecture and bench test results, the RF reference generation and distribution together with an overview of the synchronization system will be described

    Optimally adapted multi-state neural networks trained with noise

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    The principle of adaptation in a noisy retrieval environment is extended here to a diluted attractor neural network of Q-state neurons trained with noisy data. The network is adapted to an appropriate noisy training overlap and training activity which are determined self-consistently by the optimized retrieval attractor overlap and activity. The optimized storage capacity and the corresponding retriever overlap are considerably enhanced by an adequate threshold in the states. Explicit results for improved optimal performance and new retriever phase diagrams are obtained for Q=3 and Q=4, with coexisting phases over a wide range of thresholds. Most of the interesting results are stable to replica-symmetry-breaking fluctuations.Comment: 22 pages, 5 figures, accepted for publication in PR

    A Multiwavelength Consensus on the Main Sequence of Star-Forming Galaxies at z~2

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    We compare various star formation rate (SFR) indicators for star-forming galaxies at 1.4<z<2.51.4<z<2.5 in the COSMOS field. The main focus is on the SFRs from the far-IR (PACS-Herschel data) with those from the ultraviolet, for galaxies selected according to the BzK criterion. FIR-selected samples lead to a vastly different slope of the SFR-stellar mass (MM_*) relation, compared to that of the dominant main sequence population as measured from the UV, since the FIR selection picks predominantly only a minority of outliers. However, there is overall agreement between the main sequences derived with the two SFR indicators, when stacking on the PACS maps the BzK-selected galaxies. The resulting logarithmic slope of the SFR-{MM_*} relation is 0.80.9\sim0.8-0.9, in agreement with that derived from the dust-corrected UV-luminosity. Exploiting deeper 24μ\mum-Spitzer data we have characterized a sub-sample of galaxies with reddening and SFRs poorly constrained, as they are very faint in the BB band. The combination of Herschel with Spitzer data have allowed us to largely break the age/reddening degeneracy for these intriguing sources, by distinguishing whether a galaxy is very red in B-z because of being heavily dust reddened, or whether because star formation has been (or is being) quenched. Finally, we have compared our SFR(UV) to the SFRs derived by stacking the radio data and to those derived from the Hα\alpha luminosity of a sample of star-forming galaxies at 1.4<z<1.71.4<z<1.7. The two sets of SFRs are broadly consistent as they are with the SFRs derived from the UV and by stacking the corresponding PACS data in various mass bins.Comment: Accepted for publication in MNRA

    Phenomenology of BsB_s Decays

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    Using the QCD sum rules technique we study several aspects of the phenomenology of the b-flavoured strange meson Bs0B_s^0. In particular, we evaluate the mass of the particle, the leptonic constant and the form factors of the decays Bs0Ds+νˉ\overline {B_s^0} \to D^{+}_s \ell^- \bar\nu, Bs0Ds+νˉ\overline {B_s^0} \to D^{*+}_s \ell^- \bar\nu, Bs0K+νˉ\overline {B_s^0} \to K^{*+} \ell^- \bar\nu. We also calculate, in the factorization approximation, a number of two-body non leptonic Bs0\overline {B_s^0} decays.Comment: 19 pages, 2 figures (not included) available upon request, LaTex, BARI-TH/93-139, UTS-DFT-93-1

    Photonic realization of the relativistic Kronig-Penney model and relativistic Tamm surface states

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    Photonic analogues of the relativistic Kronig-Penney model and of relativistic surface Tamm states are proposed for light propagation in fibre Bragg gratings (FBGs) with phase defects. A periodic sequence of phase slips in the FBG realizes the relativistic Kronig-Penney model, the band structure of which being mapped into the spectral response of the FBG. For the semi-infinite FBG Tamm surface states can appear and can be visualized as narrow resonance peaks in the transmission spectrum of the grating
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