Thermodynamics of quantum Brownian motion with internal degrees of freedom: the role of entanglement in the strong-coupling quantum regime

We study the influence of entanglement on the relation between the statistical entropy of an open quantum system and the heat exchanged with a low temperature environment. A model of quantum Brownian motion of the Caldeira-Leggett type - for which a violation of the Clausius inequality has been stated by Th.M. Nieuwenhuizen and A.E. Allahverdyan [Phys. Rev. E 66, 036102 (2002)] - is reexamined and the results of the cited work are put into perspective. In order to address the problem from an information theoretical viewpoint a model of two coupled Brownian oscillators is formulated that can also be viewed as a continuum version of a two-qubit system. The influence of an additional internal coupling parameter on heat and entropy changes is described and the findings are compared to the case of a single Brownian particle.Comment: 10 pages, 11 figure

Stable Magnetostatic Solitons in Yttrium Iron Garnet Film Waveguides for Tilted in-Plane Magnetic Fields

The possibility of nonlinear pulses generation in Yttrium Iron Garnet thin films for arbitrary direction between waveguide and applied static in-plane magnetic field is considered. Up to now only the cases of in-plane magnetic fields either perpendicular or parallel to waveguide direction have been studied both experimentally and theoretically. In the present paper it is shown that also for other angles (besides 0 or 90 degrees) between a waveguide and static in-plane magnetic field the stable bright or dark (depending on magnitude of magnetic field) solitons could be created.Comment: Phys. Rev. B (accepted, April 1, 2002

Great Sumatra Earthquake Registers on Electrostatic Sensor

Strong electrical signals that correspond to the Mw = 9.3 earthquake of 26 December 2004, which occurred at 0058:50.7 UTC off the west coast of northern Sumatra, Indonesia, were recorded by an electrostatic sensor (a device that detects short-term variations in Earth’s electrostatic fi eld) at a seismic station in Italy, which had been installed to study the infl uence of local earthquakes on a new landslide monitoring system. Electrical signals arrived at the station practically instantaneously and were detected up to several hours before the onset of the Sumatra earthquake (Figure 1) as well as before local quakes. The corresponding seismic signals (p-waves) arrived 740 seconds after the start of the earthquake. Because the electrical signals travel at the speed of light, electrical monitoring for the global detection of very strong earthquakes could be an important tool in signifi cantly increasing the hazard alert window

Lipopeptides as dimerization inhibitors of HIV-1 protease

In AIDS therapy, attempts have been made to inhibit the virus-encoded enzymes, e.g, HIV-1 protease, using active site-directed inhibitors. This approach is questionable, however, due to virus mutations and the high toxicity of the drugs, An alternative method to inhibit the dimeric HIV protease is the targeting of the interface region of the protease subunits in order to prevent subunit dimerization and enzyme activity, This approach should be less prone to inactivation by mutation, A list of improved 'dimerization inhibitors' of HIV-1 protease is presented. The main structural features are a short `interface' peptide segment, including non-natural amino acids, and an aliphatic N-terminal blocking group. The high inhibitory power of some of the lipopeptides {[}e.g, palmitoyl-Tyr-Glu-Leu-OH, palmitoyl-Tyr-Glu-(L-thyronine)-OH, palmitoyl-Tyr-Glu-(L-biphenyl-alanine)-OH] with low nanomolar K-i values in the enzyme test suggests that mimetics with good bio-availability can be derived for AIDS therapy

Criteria for the differentiation between young and old Onchocerca volvulus filariae

Drugs exist that show long-lasting inhibition of embryogenesis and microfilaria production or macrofilaricidal activity against Onchocerca volvulus. Therefore, the patients have to be followed-up for several years. Clinical drug trials have to be performed in areas with ongoing transmission to assess the efficacy on younger worms. In addition, future vaccine trials may also require demonstrating efficacy against establishment of new worms. For the evaluation of the efficacy, it is necessary to differentiate between older worms, which were exposed to the drug, and younger worms newly acquired after drug treatment or vaccination. Here, we describe criteria for the differentiation between young and old filariae based on histological studies of worms with a known age from travellers, or from children, or patients living in areas with interrupted transmission in Burkina Faso, Ghana or Uganda. Older worms were larger and presented degenerated tissues. Gomori's iron stain showed that the worms accumulated more iron with increasing age, first in the gut and later in other organs. Using an antibody against O. volvulus lysosomal aspartic protease, the gut of young worms was stained only weakly; whereas, it was stronger labelled in older worms, accompanied by additional staining of hypodermis and epithelia. Using morphological and immunohistological criteria, it was possible to differentiate young (1–3 years old) from older females and to identify young males

Museu Militar de Bragança: fundação, práticas museológicas

O objecto de estudo decidido para este trabalho centra-se na reflexão sobre o Museu Militar de Bragança hoje, e as suas potencialidades enquanto gerador de desenvolvimento social. Para fazer esta reflexão consideramos pertinente a pesquisa histórica do museu, desde a sua fundação, atendendo à função e os objectivos propostos inicialmente pela instituição, bem como aos procedimentos museológicos actualmente observados. O museu militar de Bragança surge no primeiro quartel do século XX como um espaço de salvaguarda das memórias dos feitos bélicos das forças militares sedeadas em Bragança. Após a erradicação da última unidade militar de Bragança, em 1958, o museu é temporariamente encerrado e trasladado o acervo para o Museu Militar de Lisboa. Já na década de 80 do século XX o museu volta a ser instalado no local de origem, a torre de menagem do castelo, e impõe-se como espaço \ memória das vivências militares da cidade. No entanto, cremos que, para que o Museu Militar potencie as suas ferramentas enquanto gerador de desenvolvimento social, seria desejável consumar alguns procedimentos museológicos, actualmente já impostos na Lei Quadro dos museus. Neste sentido, na segunda parte do presente trabalho propomo-nos estabelecer um plano geral de práticas museológicas adaptado ao caso concreto do Museu Militar de Bragança. O presente trabalho aspira assim: a caracterizar sucintamente o conceito actual de Museu; a descrever o edifício onde está instalado o Museu Militar de Bragança, que constitui parte integrante da sua valência enquanto gerador de desenvolvimento local; a pesquisar o processo de fundação do museu, os seus objectivos e funções enquanto parte integrante de um maior complexo militar como era o quartel. (...

The Infrared Behavior of Gluon and Ghost Propagators in Landau Gauge QCD

A solvable systematic truncation scheme for the Dyson-Schwinger equations of Euclidean QCD in Landau gauge is presented. It implements the Slavnov-Taylor identities for the three-gluon and ghost-gluon vertices, whereas irreducible four-gluon couplings as well as the gluon-ghost and ghost-ghost scattering kernels are neglected. The infrared behavior of gluon and ghost propagators is obtained analytically: The gluon propagator vanishes for small spacelike momenta whereas the ghost propagator diverges stronger than a massless particle pole. The numerical solutions are compared with recent lattice data for these propagators. The running coupling of the renormalization scheme approaches a fixed point, $\alpha_c \simeq 9.5$, in the infrared.Comment: 4 pages, 2 figures, Revtex; revised version accepted for publication in Physical Review Letter

The polarizability model for ferroelectricity in perovskite oxides

This article reviews the polarizability model and its applications to ferroelectric perovskite oxides. The motivation for the introduction of the model is discussed and nonlinear oxygen ion polarizability effects and their lattice dynamical implementation outlined. While a large part of this work is dedicated to results obtained within the self-consistent-phonon approximation (SPA), also nonlinear solutions of the model are handled which are of interest to the physics of relaxor ferroelectrics, domain wall motions, incommensurate phase transitions. The main emphasis is to compare the results of the model with experimental data and to predict novel phenomena.Comment: 55 pages, 35 figure