Coherence effects in disordered geometries with a field-theory dual

We investigate the holographic dual of a probe scalar in an asymptotically Anti-de-Sitter (AdS) disordered background which is an exact solution of Einstein's equations in three bulk dimensions. Unlike other approaches to model disorder in holography, we are able to explore quantum wave-like interference effects between an oscillating or random source and the geometry. In the weak-disorder limit, we compute analytically and numerically the one-point correlation function of the dual field theory for different choices of sources and backgrounds. The most interesting feature is the suppression of the one-point function in the presence of an oscillating source and weak random background. We have also computed analytically and numerically the two-point function in the weak disorder limit. We have found that, in general, the perturbative contribution induces an additional power-law decay whose exponent depends on the distribution of disorder. For certain choices of the gravity background, this contribution becomes dominant for large separations which indicates breaking of perturbation theory and the possible existence of a phase transition induced by disorder.Comment: 36 pages, 19 figs, v3 accepted versio

Biomethane production improvement by enzymatic pretreatments and enhancers of sewage sludge anaerobic digestion

Enzymatic hydrolysis is recognised as an effective pre-treatment for increasing biodegradability of sludge. In this work, isolated commercial enzymes as well as in-situ enzymes producer bacteria were used respectively as enhancers and pre-treatments of sewage sludge. Biodegradability of sample as well as biomethane potential production were studied. Results showed that depuration efficiencies in terms of CODs (73.5-85.5 %) and TVS (28.5-42.7 %) were more than twice the control value. In addition, pre-treated samples as well as enhanced samples with enzymes generated more biomethane than control. The optimal ones, were those with the isolated proteases (P) and with bacteria (Bacillus licheniformis) treatment in-situ (F), producing a total volume of 72.4 ± 2.62 ml CH4 and 114 ml ± 0.46 CH4, respectively, increasing the biogas volume in 3.65 and 5.77 times respectively compared with control

Urban Rapid Transit Network Capacity Expansion

This paper examines a multi-period capacity expansion problem for rapid transit network design. The capacity expansion is realized through the location of train alignments and stations in an urban traffic context by selecting the time periods. The model maximizes the public transportation demand using a limited budget and designing lines for each period. The location problem incorporates the user decisions about mode and route. The network capacity expansion is a long-term planning problem because the network is built over several periods, in which the data (demand, resource price, etc.) are changing like the real problem changes. This complex problem cannot be solved by branch and bound, and for this reason, a heuristic approach has been defined in order to solve it. Both methods have been experimented in test networks

Elecciones en Brasil: Lula rumbo a su segundo mandato

El actual presidente brasileño, Luis Inácio “Lula” da Silva, es el candidato favorito para las elecciones del próximo 1 de octubre. Lula podría conseguir un nuevo mandato de cuatro años ya en la primera vuelta, aunque se verá obligado a llegar a pactos con otras fuerzas políticas para tener mayoría en el Parlamento. Brasil afronta las elecciones de octubre para presidente, gobernadores, diputados y senadores sin las presiones del mercado financiero que marcaron las elecciones de 2002. Los escándalos de corrupción del actual Gobierno han sido asimilados de tal modo por el electorado que el presidente Luis Inácio “Lula” da Silva podría hacerse con un segundo mandato en la primera vuelta de las elecciones. Su partido, sin embargo, pagará la factura por la crisis política, lo que obligará al próximo mandatario a llegar a pactos con organizaciones de diferente signo político para asegurarse un cierto control del futuro Parlamento. La razonable marcha de la economía, la autosuficiencia petrolífera o los programas sociales son los principales triunfos de Lula, cuya política económica seguirá la senda ortodoxa que ha recorrido estos cuatro años aunque es posible que ponga más acento en el desarrollo para intentar que el país crezca más rápidamente y se reduzcan las enormes desigualdades sociales

Fibre Monitoring System for the Beam Permit Loops at the LHC and Future Evolution of the Beam Interlock System

The optical fibres that transmit the beam permit loop signals at the CERN accelerator complex are deployed along radiation areas. This may result in increased attenuation of the fibres, which reduces the power margin of the links. In addition, other events may cause the links to not function properly and result in false dumps, reducing the availability of the accelerator chain and affecting physics data taking. In order to evaluate the state of the fibres, an out-of-band fibre monitoring system is proposed, working in parallel to the actual beam permit loops. The future beam interlock system to be deployed during LHC long shutdown 2 will implement online, real-time monitoring of the fibres, a feature the current system lacks. Commercial off-the-shelf components to implement the optical transceivers are proposed whenever possible instead of ad-hoc designs.Comment: Presented in IPAC 201

Geometrically constrained magnetic wall

The structure and properties of a geometrically constrained magnetic wall in a constriction separating two wider regions are investigated theoretically. They are shown to differconsiderably from those of an unconstrained wall, so that the geometrically constrained magnetic wall truly constitutes a new kind of magnetic wall, besides the well known Bloch and Neel walls. In particular, the width of a constrained wall cann become very small if the characteristic length of the constriction is small, as is actually the case in an atomic point contact. This provides a simple, natural explanation for the large magnetoresistance observed in ferromagnetic atomic point contacts.Comment: RevTeX, 4 pages, 4 eps figures; v2: revised version; v3: ref. adde

Perfiles de la nueva izquierda en la Argentina reciente. Acerca de las transformaciones de los movimientos de trabajadores desocupados autónomos

Considerant les transformacions produïdes en la conjuntura política argentina a partir del govern de Kirchner i la dispersió de les organitzacions de desocupats després de la massacre del Puente Pueyrredón, ens proposem d’analitzar què va succeir amb les organitzacions autònomes, arrel de la configuració del Frente Popular Darío Santillán (FPDS) des de finals de 2003. En aquest sentit, analitzarem: a) la manera en què es produeixen (re)definicions político-ideològiques, partint de la lectura que es realitza de la consolidació de l’esmentat govern i les estratègies desenvolupades en relació als diferents sectors de treballadors desocupats mobilitzats, b) les formes de construcció política del FPDS, considerant les lectures i la referència a les experiències organitzatives i de mobilització dels diferents Movimientos de Trabajadores Desocupados (MTDs) autònoms a partir dels quals es va conformar, c) les transformacions en la identitat col·lectiva, originades en el pas del reconeixement com a organització de “desocupats” a la identificació com a “front multisectorial”.Considering the transformations that have taken place in the political conjuncture in Argentina, since Kirchner’s government and the dispersion of the unemployed’s organizations after the Masacre del Puente Pueyrredón (Pueyrredón Bridge Massacre); we propose to analyze what happened with the autonomous organizations, in the light of the constitution of the Popular Front Darío Santillán (FPDS) in 2003. Thus we will analyze: a) the way in which political-ideological definitions are produced, from the interpretation of the consolidation of the mentioned government and its strategies regarding the different sectors of mobilized unemployed , b) the ways of political construction of the FPDS, considering the interpretations and the reference to the organizational and mobilization experiences of the Movimientos de Trabajadores Desocupados (Unemployed Workers Movements) from which it was constituted, c) the transformations in the collective identity, originated in the transition from the recognition as an “unemployed movement” to the identification as a “multisectorial organization”.Considerando las transformaciones que se han producido en la coyuntura política argentina a partir del gobierno de Kirchner y la dispersión entre las organizaciones de desocupados tras la masacre del Puente Pueyrredón; nos proponemos analizar qué sucedió con las organizaciones autónomas, a la luz de la conformación del Frente Popular Darío Santillán (FPDS) desde fines de 2003. En este sentido, analizaremos: a) el modo en que se producen (re) definiciones político-ideológicas, a partir de la lectura que se realiza acerca de la consolidación de dicho gobierno y las estrategias desarrolladas en relación con los diferentes sectores de trabajadores desocupados movilizados, b) los modos de construcción política del FPDS, considerando las lecturas y la referencia a las experiencias organizativas y de movilización de los diferentes Movimientos de Trabajadores Desocupados (MTDs) autónomos a partir de los cuales se conformó, c) las transformaciones en la identidad colectiva, originadas en el paso del reconocimiento como organización de “desocupados” a la identificación como “frente multisectorial”

Traceability Management Architectures Supporting Total Traceability in the Context of Software Engineering

In the area of Software Engineering, traceability is defined as the capability to track requirements, their evolution and transformation in different components related to engineering process, as well as the management of the relationships between those components. However the current state of the art in traceability does not keep in mind many of the elements that compose a product, specially those created before requirements arise, nor the appropriated use of traceability to manage the knowledge underlying in order to be handled by other organizational or engineering processes. In this work we describe the architecture of a reference model that establishes a set of definitions, processes and models which allow a proper management of traceability and further uses of it, in a wider context than the one related to software development