Solving the minimum labelling spanning tree problem using hybrid local search

Given a connected, undirected graph whose edges are labelled (or coloured), the minimum labelling spanning tree (MLST) problem seeks a spanning tree whose edges have the smallest number of distinct labels (or colours). In recent work, the MLST problem has been shown to be NP-hard and some effective heuristics (Modified Genetic Algorithm (MGA) and Pilot Method (PILOT)) have been proposed and analyzed. A hybrid local search method, that we call Group-Swap Variable Neighbourhood Search (GS-VNS), is proposed in this paper. It is obtained by combining two classic metaheuristics: Variable Neighbourhood Search (VNS) and Simulated Annealing (SA). Computational experiments show that GS-VNS outperforms MGA and PILOT. Furthermore, a comparison with the results provided by an exact approach shows that we may quickly obtain optimal or near-optimal solutions with the proposed heuristic

A cross-sectional analysis of the association between physical activity, depression, and all-cause mortality in Americans over 50 years old

Depression is estimated to be the second leading cause of disability in the United States and is associated with a 52% increased risk of death. Lifestyle components may have an important role in depression pathogenesis. The aims of this study were to analyze the association of meeting the physical activity (PA) recommendation guidelines and depression, and to analyze the all-cause mortality risk of the joint association of PA and depression. This cross-sectional study included 7201 participants from the 2007–2014 National Health and Nutrition Examination Survey aged ≥ 50 years and linked to National Death Index records through December 31, 2015. Depression was defined as a score ≥ 10 using the Patient Health Questionnaire (PHQ-9). PA was self-reported, and total PA was used to classify participants as more active (≥ 600 MET-min/week) or less active (< 600 MET-min/week). The odds ratios for depression were examined according to be more active or less active. The hazard ratios (HR) for the association of PA level and depression status with all-cause mortality were examined. Being more active was associated with reduced odds for depression. Compared with less active participants with depression, those who were more active and having depression had HR 0.45 (95% CI 0.22, 0.91, p = 0.026) for all-cause mortality. Being more active is associated with lower odds for depression and seems to be a protective factor against the increased all-cause mortality risk due to depression

Proteínas secretadas por el haustorio y su importancia en el desarrollo de Podosphaera xanthii

El cultivo de las cucurbitáceas en España se ve afectado, entre otros problemas, por Podosphaera xanthii, un hongo biotrofo obligado y principal agente causal del oídio de las cucurbitáceas. Este hongo, que requiere células vivas de la planta para completar su ciclo de vida asexual, desarrolla unas estructuras especiales de parasitismo denominadas haustorios. Los haustorios prosperan dentro de las células epidérmicas y son responsables de la relación directa entre el patógeno y el hospedador, participando en la absorción de nutrientes de la planta y en la liberación de efectores en las células del huésped. Dada la estrecha relación entre los haustorios y las células vegetales, desarrollamos un transcriptoma haustorial de novo de P. xanthii y definimos su secretoma con la intención de encontrar proteínas secretadas que sean esenciales para la patogénesis. De esta manera pudimos identificar diferentes proteínas, la mayoría de ellas sin función anotada, expresadas específicamente en el haustorio. Gracias al modelado proteico obtuvimos información relevante sobre la posible función de alguna de estas proteínas secretadas sin anotación funcional y seleccionamos varias para su validación funcional mediante silenciamiento génico en el hospedador mediado por Agrobacterium (ATM-HIGS). Además, la expresión heteróloga de las proteínas seleccionadas y los subsecuentes ensayos enzimáticos nos ha permitido corroborar su actividad bioquímica predicha. Así, pudimos comprobar cómo proteínas secretadas específicamente por el haustorio son muy importantes para el desarrollo fúngico. Este abordaje multidisciplinar nos ha permitido identificar y dilucidar la función de proteínas esenciales para P. xanthii que, dado su papel clave, se convierten en dianas esperanzadoras para el desarrollo de nuevo fitosanitarios contra el oídio de las cucurbitáceas y otros hongos fitopatógenos.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Este trabajo ha sido financiado por el Ministerio de Economía y Competitividad (AGL2013-41939-R; AGL2016-76216-C2-1-R) cofinanciado con fondos FEDER (UE). Álvaro Polonio es beneficiario de un contrato predoctoral (BES-2014-068602) para la formación de doctores del Ministerio de Economía y Competitividad. Los autores también agradecen ayudas del Plan Propio de Investigación de la Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

TR3 A Multi-National Survey Assessing the Relationship Between Prophylaxis Treatment and Health-Related Quality of Life Among Severe Hemophilia a Patients in Latin America

Pericas, Enric;Ordóñez, Estrell

Graphene Synthesis Using a CVD Reactor and a Discontinuous Feed of Gas Precursor at Atmospheric Pressure

The present work shows a new method in order to cost-effectively achieve the synthesis of graphene by Chemical Vapor Deposition (CVD). Unlike most usual processes, where precursors such as argon, H2, CH4, and high purity copper foil are used, the proposed method has replaced the previous ones by N2, N2 (90%) : H2 (10%), C2H2, and electrolytic copper (technical grade) since the use of industrialized precursors helps reduce production costs. On the other hand, the process was modified from a continuous flow system with vacuum to a discontinuous one at atmospheric pressure, eliminating the use of vacuum pump. In addition, this modification optimized the consumption of gases, which reduced the waste and the emission of pollutant gases into the atmosphere. Graphene films were grown under different gas flowrates and temperatures. Then, the obtained material was characterized by TEM, Raman spectroscopy, and AFM, confirming the presence of few graphene layers. In brief, the growth time was reduced to six minutes with acetylene as a carbon precursor at 1000°C and at atmospheric pressure, with a flow rate of 30 sccm. Finally, the reported conditions can be used for the synthesis of good quality graphene films in industrial applications

Study of CT Images Processing with the Implementation of MLEM Algorithm using CUDA on NVIDIA’S GPU Framework

In medicine, the acquisition process in Computed Tomography Images (CT) is obtained by a reconstruction algorithm. The classical method for image reconstruction is the Filtered Back Projection (FBP). This method is fast and simple but does not use any statistical information about the measurements. The appearance of artifacts and its low spatial resolution in reconstructed images must be considered. Furthermore, the FBP requires of optimal conditions of the projections and complete sets of data. In this paper a methodology to accelerate acquisition process for CT based on the Maximum Likelihood Estimation Method (MLEM) algorithm is presented. This statistical iterative reconstruction algorithm uses a GPU Programming Paradigms and was compared with sequential algorithms in which the reconstruction time was reduced by up to 3 orders of magnitude while preserving image quality. Furthermore, they showed a good performance when compared with reconstruction methods provided by commercial software. The system, which would consist exclusively of a commercial laptop and GPU could be used as a fast, portable, simple and cheap image reconstruction platform in the future

The Mpemba effect in spin glasses is a persistent memory effect

The Mpemba effect occurs when a hot system cools faster than an initially colder one, when both are refrigerated in the same thermal reservoir. Using the custom built supercomputer Janus II, we study the Mpemba effect in spin glasses and show that it is a non-equilibrium process, governed by the coherence length \xi of the system. The effect occurs when the bath temperature lies in the glassy phase, but it is not necessary for the thermal protocol to cross the critical temperature. In fact, the Mpemba effect follows from a strong relationship between the internal energy and \xi that turns out to be a sure-tell sign of being in the glassy phase. Thus, the Mpemba effect presents itself as an intriguing new avenue for the experimental study of the coherence length in supercooled liquids and other glass formers.Comment: Version accepted for publication in PNAS. 6 pages, 7 figure