Charging Effects and Quantum Crossover in Granular Superconductors

The effects of the charging energy in the superconducting transition of granular materials or Josephson junction arrays is investigated using a pseudospin one model. Within a mean-field renormalization-group approach, we obtain the phase diagram as a function of temperature and charging energy. In contrast to early treatments, we find no sign of a reentrant transition in agreement with more recent studies. A crossover line is identified in the non-superconducting side of the phase diagram and along which we expect to observe anomalies in the transport and thermodynamic properties. We also study a charge ordering phase, which can appear for large nearest neighbor Coulomb interaction, and show that it leads to first-order transitions at low temperatures. We argue that, in the presence of charge ordering, a non monotonic behavior with decreasing temperature is possible with a maximum in the resistance just before entering the superconducting phase.Comment: 15 pages plus 4 fig. appended, Revtex, INPE/LAS-00

Improving emergency plans management with SAGA

[EN] Emergency plans are the tangible result of the preparedness activities of the emergency management lifecycle. In many countries, public service organizations have the legal obligation to develop and maintain emergency plans covering all possible hazards relative to their areas of operation. However, little support is provided to planners in the development and use of plans. Often, advances in software technology have not been exploited, and plans remain as text documents whose accessibility is very limited. In this paper, we advocate for the definition and implementation of plan management processes as the first step to better produce and manage emergency plans. The main contribution of our work is to raise the need for IT-enabled planning environments, either at the national or organization-specific levels, which can lead to more uniform plans that are easier to evaluate and share, with support to stakeholders other than responders, among other advantages. To illustrate our proposal, we introduce SAGA, a framework that supports the full lifecycle of emergency plan management. SAGA provides all the actors involved in plan management with a number of tools to support all the stages of the plan lifecycle. We outline the architecture of the system, and show with a case study how planning processes can benefit from a system like SAGA.We thank J. Marzal and R. Garrido, from the UPV Prevention Service, for their cooperation in the early design of SAGA. The work of J.H. Canós, M.C. Penadés, M. Llavador and A. Gómez is partially funded by the Spanish Ministerio de Educación y Ciencia (MEC) under grant TIPEx (TIN2010-19859-C03-03). The work of M.R.S. Borges is partially supported by grant nos. 560223/2010-2 and 308003/2011-0 from CNPq (Brazil) and grant no. E-26/103.076/2011 from FAPERJ (Brazil). The cooperation between the Brazilian and the Spanish research groups was partially sponsored by the CAPES/MECD Cooperation Program, Project #169/PHB2007-0064-PC.Canos Cerda, JH.; Borges, M.; Penadés Gramage, MC.; Gómez Llana, A.; Llavador Campos, M. (2013). Improving emergency plans management with SAGA. Technological Forecasting and Social Change. 80(9):1868-1876. https://doi.org/10.1016/j.techfore.2013.02.014S1868187680

Characterizing top gated bilayer graphene interaction with its environment by Raman spectroscopy

In this work we study the behavior of the optical phonon modes in bilayer graphene devices by applying top gate voltage, using Raman scattering. We observe the splitting of the Raman G band as we tune the Fermi level of the sample, which is explained in terms of mixing of the Raman (Eg) and infrared (Eu) phonon modes, due to different doping in the two layers. We theoretically analyze our data in terms of the bilayer graphene phonon self-energy which includes non-homogeneous charge carrier doping between the graphene layers. We show that the comparison between the experiment and theoretical model not only gives information about the total charge concentration in the bilayer graphene device, but also allows to separately quantify the amount of unintentional charge coming from the top and the bottom of the system, and therefore to characterize the interaction of bilayer graphene with its surrounding environment

A framework for variable content document generation with multiple actors

“NOTICE: this is the author’s version of a work that was accepted for publication in Information and Software Technology. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Information and Software Technology, Volume 56, Issue 9, September 2014, Pages 1101–1121 DOI10.1016/j.infsof.2013.12.006Context - Advances in customization have highlighted the need for tools supporting variable content document management and generation in many domains. Current tools allow the generation of highly customized documents that are variable in both content and layout. However, most frameworks are technology-oriented, and their use requires advanced skills in implementation-related tools, which means their use by end users (i.e. document designers) is severely limited. Objective - Starting from past and current trends for customized document authoring, our goal is to provide a document generation alternative in which variants are specified at a high level of abstraction and content reuse can be maximized in high variability scenarios. Method Based on our experience in Document Engineering, we identified areas in the variable content document management and generation field open to further improvement. We first classified the primary sources of variability in document composition processes and then developed a methodology, which we called DPL based on Software Product Lines principles to support document generation in high variability scenarios. Results - In order to validate the applicability of our methodology we implemented a tool DPLfw to carry out DPL processes. After using this in different scenarios, we compared our proposal with other state-of-the-art tools for variable content document management and generation. Conclusion - The DPLfw showed a good capacity for the automatic generation of variable content documents equal to or in some cases surpassing other currently available approaches. To the best of our knowledge, DPLfw is the only framework that combines variable content and document workflow facilities, easing the generation of variable content documents in which multiple actors play different roles.This work has been partially funded by the Spanish Ministerio de Economia y Competitividad under Grant TIPEx (TIN2010-19859-C03-03).Gómez Llana, A.; Penadés Gramage, MC.; Canos Cerda, JH.; Borges, MR.; Llavador Campos, M. (2014). A framework for variable content document generation with multiple actors. Information and Software Technology. 56(9):1101-1121. https://doi.org/10.1016/j.infsof.2013.12.006S1101112156

Proficiency testing of virus diagnostics based on bioinformatics analysis of simulated in silico high-throughput sequencing data sets

Quality management and independent assessment of high-throughput sequencing-based virus diagnostics have not yet been established as a mandatory approach for ensuring comparable results. The sensitivity and specificity of viral high-throughput sequence data analysis are highly affected by bioinformatics processing using publicly available and custom tools and databases and thus differ widely between individuals and institutions. Here we present the results of the COMPARE [Collaborative Management Platform for Detection and Analyses of (Re-) emerging and Foodborne Outbreaks in Europe] in silico virus proficiency test. An artificial, simulated in silico data set of Illumina HiSeq sequences was provided to 13 different European institutes for bioinformatics analysis to identify viral pathogens in high-throughput sequence data. Comparison of the participants’ analyses shows that the use of different tools, programs, and databases for bioinformatics analyses can impact the correct identification of viral sequences from a simple data set. The identification of slightly mutated and highly divergent virus genomes has been shown to be most challenging. Furthermore, the interpretation of the results, together with a fictitious case report, by the participants showed that in addition to the bioinformatics analysis, the virological evaluation of the results can be important in clinical settings. External quality assessment and proficiency testing should become an important part of validating high-throughput sequencing-based virus diagnostics and could improve the harmonization, comparability, and reproducibility of results. There is a need for the establishment of international proficiency testing, like that established for conventional laboratory tests such as PCR, for bioinformatics pipelines and the interpretation of such results