Los nuevos escenarios para la cooperación en la lucha contra el terrorismo internacional

Not availableEl terrorismo constituye una de las amenazas mas serias para la democracia, para el libre ejercicio de los derechos del hombre y para el desarrollo económico y social. Los acontecimientos del 11 de septiembre mostraron que el terrorismo es una amenaza real a nivel mundial y que cualquier país podía ser afectado por ataques terroristas. Es un verdadero reto para el mundo y para Europa. La Unión Europea se fijó como objetivo en el tratado de la UE «ofrecer a los ciudadanos un alto grado de seguridad dentro de un espolio de libertad, seguridad y justicia elaborando una acción en común entre los Estados miembros en los ámbitos de la cooperación policial y judicial en materia penal...». Este objetivo ha de lograrse mediante la prevención y la lucha contra la delincuencia, organizada o no, en particular el terrorismo a través de una mayor cooperación entre las fuerzas policiales, las autoridades aduaneras y otras autoridades competentes de los Estados miembros, como entre les autoridades judiciales y, también, por la aproximación, cuando proceda, de las normas de los Estados miembro en materia penal

Attractive Potential around a Thermionically Emitting Microparticle

We present a simulation study of the charging of a dust grain immersed in a plasma, considering the effect of electron emission from the grain (thermionic effect). It is shown that the OML theory is no longer reliable when electron emission becomes large: screening can no longer be treated within the Debye-Huckel approach and an attractive potential well forms, leading to the possibility of attractive forces on other grains with the same polarity. We suggest to perform laboratory experiments where emitting dust grains could be used to create non-conventional dust crystals or macro-molecules.Comment: 3 figures. To appear on Physical Review Letter

Very High Mach Number Electrostatic Shocks in Collisionless Plasmas

The kinetic theory of collisionless electrostatic shocks resulting from the collision of plasma slabs with different temperatures and densities is presented. The theoretical results are confirmed by self-consistent particle-in-cell simulations, revealing the formation and stable propagation of electrostatic shocks with very high Mach numbers ($M \gg 10$), well above the predictions of the classical theories for electrostatic shocks.Comment: 6 pages, submitted to Phys. Rev. Let

Hepatitis B Virus Reactivation and Efficacy of Prophylaxis with Lamivudine in Patients Undergoing Allogeneic Stem Cell Transplantation

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Discrete Breathers in Hexagonal Dusty Plasma Lattices

The occurrence of single- or multisite localized vibrational modes, also called Discrete Breathers (DBs), in 2D hexagonal dusty plasma (DP) lattices is investigated. The system is described by a Klein-Gordon hexagonal lattice characterized by a negative coupling parameter \e in account of its inverse dispersive behavior. A theoretical analysis is performed in order to establish the possibility of existence of single- as well as three-site DBs in such systems. The study is complemented by a numerical investigation based on experimentally provided potential forms. This investigation shows that a DP lattice can support single site DBs while three-site in phase breathers could exist if specific conditions, about the inter-grain interaction strength, would hold. On the other hand, out of phase and vortex three site breathers cannot be supported since they are highly unstable

Magnetic field amplification and electron acceleration to near-energy equipartition with ions by a mildly relativistic quasi-parallel plasma protoshock

The prompt emissions of gamma-ray bursts are seeded by radiating ultrarelativistic electrons. Internal shocks propagating through a jet launched by a stellar implosion, are expected to amplify the magnetic field & accelerate electrons. We explore the effects of density asymmetry & a quasi-parallel magnetic field on the collision of plasma clouds. A 2D relativistic PIC simulation models the collision of two plasma clouds, in the presence of a quasi-parallel magnetic field. The cloud density ratio is 10. The densities of ions & electrons & the temperature of 131 keV are equal in each cloud. The mass ratio is 250. The peak Lorentz factor of the electrons is determined, along with the orientation & strength of the magnetic field at the cloud collision boundary. The magnetic field component orthogonal to the initial plasma flow direction is amplified to values that exceed those expected from shock compression by over an order of magnitude. The forming shock is quasi-perpendicular due to this amplification, caused by a current sheet which develops in response to the differing deflection of the incoming upstream electrons & ions. The electron deflection implies a charge separation of the upstream electrons & ions; the resulting electric field drags the electrons through the magnetic field, whereupon they acquire a relativistic mass comparable to the ions. We demonstrate how a magnetic field structure resembling the cross section of a flux tube grows in the current sheet of the shock transition layer. Plasma filamentation develops, as well as signatures of orthogonal magnetic field striping. Localized magnetic bubbles form. Energy equipartition between the ion, electron & magnetic energy is obtained at the shock transition layer. The electronic radiation can provide a seed photon population that can be energized by secondary processes (e.g. inverse Compton).Comment: 12 pages, 15 Figures, accepted to A&