Estimating entanglement of unknown states

The experimental determination of entanglement is a major goal in the quantum information field. In general the knowledge of the state is required in order to quantify its entanglement. Here we express a lower bound to the robustness of entanglement of a state based only on the measurement of the energy observable and on the calculation of a separability energy. This allows the estimation of entanglement dismissing the knowledge of the state in question.Comment: 3 pages, 1 figure. Comments welcome. V2: references updated. Accepted version by Applied Physics Letter

Event-driven field estimation for wireless sensor networks

This paper introduces and analyzes a field estimation scheme for wireless sensor networks. Our scheme imitates the response of living beings to the surrounding events. The sensors define their periphery of attention based on their own readings. Readings differing from the expected behavior are considered events of interest and trigger the data transmission to the sink. The presented scheme is evaluated with real-site-collected data and the tradeoff between the amount of data sent to the sink and the reconstruction error is analyzed. Results show that signifcant reduction in the data transmission and, as a consequence, in the energy consumption of the network is achievable while keeping low the average reconstruction error.8th IFIP/IEEE International conference on Mobile and Wireless CommunicationRed de Universidades con Carreras en Informática (RedUNCI

Event-driven field estimation for wireless sensor networks

This paper introduces and analyzes a field estimation scheme for wireless sensor networks. Our scheme imitates the response of living beings to the surrounding events. The sensors define their periphery of attention based on their own readings. Readings differing from the expected behavior are considered events of interest and trigger the data transmission to the sink. The presented scheme is evaluated with real-site-collected data and the tradeoff between the amount of data sent to the sink and the reconstruction error is analyzed. Results show that signifcant reduction in the data transmission and, as a consequence, in the energy consumption of the network is achievable while keeping low the average reconstruction error.8th IFIP/IEEE International conference on Mobile and Wireless CommunicationRed de Universidades con Carreras en Informática (RedUNCI

Translating between Alloy specifications and UML class diagrams annotated with OCL

Model-driven engineering (MDE) is a software engineering approach based on model transformations at different abstraction levels. It prescribes the development of software by successively transforming the models from abstract (specifications) to more concrete ones (code). Alloy is an increasingly popular lightweight formal specification language that supports automatic verification. Unfortunately, its widespread industrial adoption is hampered by the lack of an ecosystem of MDE tools, namely code generators. This paper presents a model transformation from Alloy to UML class diagrams annotated with OCL (UML+OCL) and shows how an existing transformation from UML+OCL to Alloy can be improved to handle dynamic issues. The proposed bidirectional transformation enables a smooth integration of Alloy in the current MDE contexts, by allowing UML+OCL specifications to be transformed to Alloy for validation and verification, to correct and possibly refine them inside Alloy, and to translate them back to UML+OCL for sharing with stakeholders or to reuse current model-driven architecture tools to refine them toward code.This work was funded by European Regional Development Fund (ERDF) through the COMPETE Programme (operational program for competitiveness) and by national funds through the FCT (Fundaaco para a Ciencia e a Tecnologia-portuguese Foundation for Science and Technology) within project FCOMP-01-0124-FEDER-020532. Part of the work was done while the first author was visiting the Software Design Group at CSAIL, MIT, USA, funded by FCT sabbatical grant SFRH/BSAB/1187/2011. The second author was also partially supported by QREN (the portuguese National Strategy Reference Chart) project 1621, while visiting the High-Assurance Software Laboratory at Universidade do Minho, Portugal. Finally, we would also like to thank all anonymous reviewers for the valuable comments and suggestions

Mechanical characterization of Iroko wood using small specimens

Despite their favorable physical and mechanical properties for structural use, tropical woods, such as Iroko (Milicia excelsa), present knowledge gaps to be filled mainly about their mechanical characterization, which currently limit their use or result in under- or overdimensioned structural elements. Visual classification, one of the most used methods for characterizing wood, is inaccurate in the case of Iroko due to the wide variety of geographical locations in which this species can be found. In addition, mechanical characterization using test pieces with structural dimensions leads to high and impractical costs. In this context, this study aims to verify the mechanical properties of Iroko (imported from the Republic of the Congo) from small size specimens, a process that is currently standardized only for softwoods, and to verify the correlation of different properties through bending properties and ultrasound tests. Prior to the bending tests, the speed of propagation of ultrasonic waves was measured using the direct method. The results obtained show a good correlation between density and bending properties and the velocity of propagation of ultrasonic waves

Long-term effects of psychotherapy on moderate depression: a comparative study of narrative therapy and cognitive-behavioral therapy

Background: In a previous clinical controlled trial (Lopes et al., 2014), narrative therapy (NT) showed promising results in ameliorating depressive symptoms with comparable outcomes to cognitivebehavioral therapy (CBT) when patients completed treatment. This paper aims to assess depressive symptoms and interpersonal problems in this clinical sample at follow-up. Methods: Using the Beck Depression Inventory-II and Outcome Questionnaire-45.2 Interpersonal Relations Scale, naturalistic prospective follow-up assessment was conducted at 21 and 31 months after the last treatment session. Results: At follow-up, patients kept improving in terms of depressive symptoms and interpersonal problems. The odds that a patient maintained recovery from depressive symptoms at follow-up were five times higher than the odds that a patient maintained recovery from interpersonal problems. In the same way, the odds of a patient never recovering from interpersonal problems were five times higher than the odds of never recovering from depressive symptoms. Limitations: The study did not control for the natural course of depression or treatment continuation. Conclusions: For depressed patients with greater interpersonal disabilities, longer treatment plans and alternative continuation treatments should be considered.The Portuguese Foundation for Science and Technology (FCT) supported this article through the Research Project "Ambivalence and Unsuccessful Psychotherapy" [PTDC/PSI-PCL/121525/2010], coordinated by M. Goncalves, and through a doctoral grant to R. Lopes [SFRH/BD/47343/2008].The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

High-frequencies in TESS A–F main sequence stars

The driving mechanism for high-frequency oscillations in some chemically peculiar Ap stars, the roAp stars, is not understood. The TESS data provide an ideal opportunity to extend the number of roAp stars which might provide further clues to address this problem. From an examination of over 18000 stars in TESS sectors 1–7, we have discovered high-frequency pulsations in 14 A–F stars, of which only 3 are classified as Ap stars. In addition to these new discoveries, we discuss the frequencies in 9 previously known roAp stars. In one of these stars, HD 60435, we confirm a previous finding that the pulsations have lifetimes of only a few days. In another known roAp star, HD 6532, the relative amplitudes of the rotationally-modulated sidelobes, which are generally used to estimate the inclination of the magnetic axis relative to the rotational axis, are significantly different from those found in ground-based B-band photometric observations. We also discuss 4 δ Scuti stars which appear to have independent frequencies similar to those of roAp stars

Single-Source Pulsed Laser Deposited Perovskite Solar Cells with > 19% Efficiency

Single-source vapor deposition of metal halide perovskites has, to date, remained challenging due to the dissimilar volatilities of the perovskite precursors, limiting the controlled transfer of multiple elements at once. This Chapter demonstrates that pulsed laser deposition (PLD) addresses the rate-control challenges of single-source evaporation, enabling solar cells with power conversion efficiencies (PCE) above 19%. For this, we combined dry mechanochemical synthesis and PLD to fabricate MA1-xFAxPbI3 and Cl-passivated MA1-xFAxPbI3 films from a single-source target. The films are grown onto hole-selective self-assembled monolayers (SAMs-2PACz), where first a thin PbI2-rich layer forms, leading to full perovskite conversion as confirmed by grazing-incidence wide-angle X-ray scattering. Onto the perovskite, an oleylammonium iodide (OAmI) post-treatment is then applied to passivate its top surface by forming a 2D perovskite film. This was followed via in-situ PL monitoring during the 2D application. Further, we found that when incorporating PbCl2 in the target and OAmI-based 2D passivation, a remarkable 19.7% PCE for p–i–n perovskite solar cells is achieved with enhanced device stability. These findings emphasize the importance of interface and passivation strategies to improve the performance of PSC-containing vapor-deposited absorbers. Further, these results represent one of the highest PCEs achieved within the state-of-the-art single-source vapor deposition methods, as far as our knowledge extends. Consequently, this study highlights the appeal of PLD to fully unlock the potential of single-source vapor-deposited perovskite towards low-cost and efficient photovoltaics