Microquasars: disk-jet coupling in stellar-mass black holes

Microquasars provide new insights into: 1) the physics of relativistic jets from black holes, 2) the connection between accretion and ejection, and 3) the physical mechanisms in the formation of stellar-mass black holes. Furthermore, the studies of microquasars in our Galaxy can provide in the future new insights on: 1) a large fraction of the ultraluminous X-ray sources in nearby galaxies, 2) gamma-ray bursts (GRBs) of long duration in distant galaxies, and 3) the physics in the jets of blazars. If jets in GRBs, microquasars and Active Galactic Nuclei (AGN) are due to a unique universal magnetohydrodynamic mechanism, synergy of the research on these three different classes of cosmic objects will lead to further progress in black hole physics and astrophysics.Comment: 4 pages, 3 figures. To appear in Proceedings of IAU Symp. No 238 "Black Holes: from Stars to Galaxies - across the Range of Masses. Held in Prague, August 21-25, 2006. Eds. V. Karas & G. Mat

Characteristics of stress-induced defects under positive bias in high-k/InGaAs stacks

The introduction of InGaAs as a channel material for complementary metal-oxide-semiconductor technology presents major challenges in terms of the characterization of the various defects that affect the performance and reliability. Understanding the generation of defects by constant voltage stresses is crucial in terms of their concentration profiles and energy levels. In particular, we want to understand the real nature of the defects responsible for the dispersion of C-V in strong accumulation. Here, we show that the degradation under positive bias of metal/Al2O3/n-InGaAs capacitors reveals two contributions depending on the temperature that affects the C-V curves in a different way. Based on features of stressed C-V curves, it is possible to estimate the onset point of the distribution of border traps near the midgap condition. The results suggest that these defects are strongly related to the characteristics of the InGaAs substrate.Fil: Palumbo, Félix Roberto Mario. Technion - Israel Institute of Technology; Israel. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Winter, R.. Technion - Israel Institute of Technology; IsraelFil: Krylov, I.. Technion - Israel Institute of Technology; IsraelFil: Eizenberg, M.. Technion - Israel Institute of Technology; Israe

La Junta de Protecció de la Infància de Barcelona : la primera etapa (1908-1909) = The Childhood Protection Council in Barcelona : Its first Stage (1908-1909)

L'article presenta la constitució de la Junta Provincial de Protecció de Barcelona i la tasca que va desenvolupar fins a finals de 1909, quan es va dissoldre. Aporta les dades del primer pla d'acció que es va dur a terme a la capital catalana per combatre la marginació i la desviació social de la infància, i n'assenyala els elements més característics i les dificultats que hi va haver per aplicar-lo. L'estudi està basat en fonts documentals primàries, procedents dels arxius privats d'alguns dels protagonistes principals de la història que es narra.The aim of this paper is to present the constitution of the «Junta Provincial de Protección de la Infancia» in Barcelona in 1908, and describe the task it carried out in order to fight against social deviation and margination of childhood until the end of 1909, when due to economical difficulties it was forced to dissolve. The study is divided in two parts, the first of them is focused in giving a summary of the general legislative context (Childhood Protection Law 1904 and its Regulation in 1908) that allowed the foundation of the Local and Provincial Councils of Childhood Protection. In the second one, the study explains the concrete case of the Protection Council in Barcelona during the period of 1908 and 1909. It is analysed the social and educational intervention plan designed by the Council and the way it was applied, showing its most significant elements and the difficulties found. The paper is basically based on primary documental sources, coming from some of the process’ main characters’ personal archives (Josep Pedragosa and Ramón Albó), and also from the Protection Council’s own archives. The use of such kind of sources enables to enrich the strict institutional history.El artículo presenta la constitución de la Junta Provincial de Protección de Barcelona y la tarea que desarrolló hasta finales de 1909, cuando se disolvió. Aporta los datos del primero plan de acción que se llevó a término a la capital catalana por combatir la marginación y la desviación social de la infancia, y señala sus elementos más característicos y las dificultades con qué se encontró su aplicación. El estudio está basado en fuentes documentales primarias, procedentes de los archivos privados de algunos de los protagonistas principales de la historia que se narra

Magnetization vector in the reversible region of a highly anisotropic cuprate superconductor: anisotropy factor and the role of 2D vortex fluctuations

By using a high quality Tl2Ba2Ca2Cu3O10 (Tl-2223) single crystal as an example, the magnetization vector was probed in the reversible region of highly anisotropic cuprate superconductors. For that, we have measured its components along and transverse to the applied magnetic field for different crystal orientations. The analysis shows that the angular dependence of the perpendicular component of the magnetization vector follows the one predicted by a London-like approach which includes a contribution associated with the thermal fluctuations of the 2D vortex positions. For the Tl-2223 crystal studied here, a lower bound for the anisotropy factor was estimated to be about 190.Comment: 6 pages, 3 figure

Black holes: from stars to galaxies

While until recently they were often considered as exotic objects of dubious existence, in the last decades there have been overwhelming observational evidences for the presence of stellar mass black holes in binary systems, supermassive black holes at the centers of galaxies, and possibly, intermediate-mass black holes observed as ultraluminous X-ray sources in nearby galaxies. Black holes are now widely accepted as real physical entities that play an important role in several areas of modern astrophysics. Here I review the concluding remarks of the IAU Sympposium No 238 on Black Holes, with particular emphasis on the topical questions in this area of research.Comment: Invited talk. Concluding Remarks of IAU Symposium 238: "Black Holes: From Stars to Galaxies -Across the Range of Masses". Prague 14-18 August 200

Effect of pH and nanoclay content on the morphology and physicochemicalproperties of soy protein/montmorillonite nanocomposite obtained byextrusion

The present work attempts to clarify the influence of montmorillonite nanoclay content and pH on the me-chanical properties of extruded soy protein nanocomposites. The mechanical behaviour is dominated by theformation of positive synergies between protein and nanoclay above a nanoclay concentration threshold.Moreover, the presence of nanoclay can improve water uptake. The pH also exerts a strong influence on me-chanical and water absorption properties, although montmorillonite tend to reduce this effect.Eventually, this study put forward the feasibility of using a combination of soy protein and montmorillonite toobtain potentially attractive biodegradable nanocomposite materials, processed by means of a simple and easilyscalable twin-screw extruder.Junta de Andalucía (project TEP-6134)Ministerio de Economía y Competitividad (CTQ2015-71164-P

Photon-Number-Splitting versus Cloning Attacks in Practical Implementations of the Bennett-Brassard 1984 protocol for Quantum Cryptography

In practical quantum cryptography, the source sometimes produces multi-photon pulses, thus enabling the eavesdropper Eve to perform the powerful photon-number-splitting (PNS) attack. Recently, it was shown by Curty and Lutkenhaus [Phys. Rev. A 69, 042321 (2004)] that the PNS attack is not always the optimal attack when two photons are present: if errors are present in the correlations Alice-Bob and if Eve cannot modify Bob's detection efficiency, Eve gains a larger amount of information using another attack based on a 2->3 cloning machine. In this work, we extend this analysis to all distances Alice-Bob. We identify a new incoherent 2->3 cloning attack which performs better than those described before. Using it, we confirm that, in the presence of errors, Eve's better strategy uses 2->3 cloning attacks instead of the PNS. However, this improvement is very small for the implementations of the Bennett-Brassard 1984 (BB84) protocol. Thus, the existence of these new attacks is conceptually interesting but basically does not change the value of the security parameters of BB84. The main results are valid both for Poissonian and sub-Poissonian sources.Comment: 11 pages, 5 figures; "intuitive" formula (31) adde

Semianalytical calculation of the zonal-flow oscillation frequency in stellarators

Due to their capability to reduce turbulent transport in magnetized plasmas, understanding the dynamics of zonal flows is an important problem in the fusion programme. Since the pioneering work by Rosenbluth and Hinton in axisymmetric tokamaks, it is known that studying the linear and collisionless relaxation of zonal flow perturbations gives valuable information and physical insight. Recently, the problem has been investigated in stellarators and it has been found that in these devices the relaxation process exhibits a characteristic feature: a damped oscillation. The frequency of this oscillation might be a relevant parameter in the regulation of turbulent transport, and therefore its efficient and accurate calculation is important. Although an analytical expression can be derived for the frequency, its numerical evaluation is not simple and has not been exploited systematically so far. Here, a numerical method for its evaluation is considered, and the results are compared with those obtained by calculating the frequency from gyrokinetic simulations. This "semianalytical" approach for the determination of the zonal-flow frequency reveals accurate and faster than the one based on gyrokinetic simulations.Comment: 30 pages, 14 figure

Inadequate Content of Docosahexaenoic Acid (DHA) of Donor Human Milk for Feeding Preterm Infants: A Comparison with Mother's Own Milk at Different Stages of Lactation

A cross-sectional single-center study was designed to compare the fatty acids profile, particularly docosahexaenoic acid (DHA) levels, between milk banking samples of donor human milk and mother's own milk (MOM) for feeding preterm infants born before 32 weeks' gestation. MOM samples from 118 mothers included colostrum (1-7 days after delivery), transitional milk (9-14 days), and mature milk (15-28 days and ≥29 days). In the n-3 polyunsaturated fatty acids (PUFAs) group, the levels of α-linolenic acid (C18:3 n3) and DHA (C22:6 n3) showed opposite trends, whereas α-linolenic acid was higher in donor human milk as compared with MOM, with increasing levels as stages of lactation progressed, DHA levels were significantly lower in donor human milk than in MOM samples, which, in turn, showed decreasing levels along stages of lactation. DHA levels in donor human milk were 53% lower than in colostrum. Therefore, in preterm infants born before 32 weeks' gestation, the use of pasteurized donor human milk as exclusive feeding or combined with breastfeeding provides an inadequate supply of DHA. Nursing mothers should increase DHA intake through fish consumption or nutritional supplements with high-dose DHA while breastfeeding. Milk banking fortified with DHA would guarantee adequate DHA levels in donor human milk