Community structure in industrial SAT instances

Modern SAT solvers have experienced a remarkable progress on solving industrial instances. It is believed that most of these successful techniques exploit the underlying structure of industrial instances. Recently, there have been some attempts to analyze the structure of industrial SAT instances in terms of complex networks, with the aim of explaining the success of SAT solving techniques, and possibly improving them. In this paper, we study the community structure, or modularity, of industrial SAT instances. In a graph with clear community structure, or high modularity, we can find a partition of its nodes into communities such that most edges connect variables of the same community. Representing SAT instances as graphs, we show that most application benchmarks are characterized by a high modularity. On the contrary, random SAT instances are closer to the classical Erdös-Rényi random graph model, where no structure can be observed. We also analyze how this structure evolves by the effects of the execution of a CDCL SAT solver, and observe that new clauses learned by the solver during the search contribute to destroy the original structure of the formula. Motivated by this observation, we finally present an application that exploits the community structure to detect relevant learned clauses, and we show that detecting these clauses results in an improvement on the performance of the SAT solver. Empirically, we observe that this improves the performance of several SAT solvers on industrial SAT formulas, especially on satisfiable instances.Peer ReviewedPostprint (published version

Qué es y como afrontar el trastorno de expresión escrita: orientaciones prácticas

Decenes Jornades de Foment de la Investigació de la FCHS (Any 2004-2005)En los últimos años la población analfabeta era mínima (casi inexistente) gracias entre otros factores, a la escolarización temprana y obligatoria y a las facilidades de poder continuar los estudios de enseñanza no obligatoria (según el libro del Instituto Nacional de Estadística (INE)). Aunque la mayoría de la población no tiene dificultades en la escritura cada vez aparecen más casos de niños que tienen dificultades en la expresión escrita, aunque el número en comparación con la población general es mínima, aunque el trastorno más común y más estudiado es el de lecto-escritura, hay niños con dificultades sólo en la escritura. Muchos investigadores se sorprenden ante el hecho de que los niños no tengan realmente más dificultades para aprender a escribir ya que la actividad de escribir es sumamente compleja y en la que intervienen multitud de procesos cognitivos de todo tipo, desde decidir que vamos a contar, en que orden, cómo lo vamos a contar, que oraciones y palabras emplear, los movimientos musculares a realizar para obtener las letras, etc. Elbow (1973) va aún más allá al afirmar que “es teóricamente imposible aprende a escribir”. Debido a la complejidad de la escritura, en el presente trabajo vamos abordar cuales son los principales aspectos que hay que tener en cuenta en niños con dificultades en expresión escrita (conceptos, diagnóstico, intervención, orientaciones para el profesorado, orientaciones para los padres, nuevas tecnologías, casos, etc.)

HPLC method with electrochemical detection on gold electrode for simultaneous determination of different antimicrobial agents in cosmetics

Antimicrobial agents are added to a wide variety of products such as cosmetics to reduce the risk of microbial contamination and ensure the suitability and safety of the product. However, recent studies have shown that these compounds can have negative effects on human health and the environment. Therefore, it is crucial to develop analytical methods to control the amount of these compounds in personal care products to guarantee human health and product quality. This paper presents an HPLC method with electrochemical detection using a gold electrode for the determination of the most used antimicrobial agents in cosmetic products: methylparaben (MP), 4-hydroxybenzoic acid (4-HBA), phenoxyethanol (PE) and methylisothiazolinone (MIT). For this purpose, the electrochemical response of these compounds was evaluated on the gold electrode. The optimal electrochemical detection of MP, 4-HBA; PE and MIT was performed at pH 2 and + 1.50 V (vs Ag/AgCl). Under the optimal separation and detection conditions, limits of detection (LODs) between 10 and 110 μg L− 1 were obtained. These LODs are lower than those previously reported for other HPLC methods with mass spectrometry and diode-array detectors. Cosmetic products with different compositions were successfully analysed with the proposed HPLC method obtaining recoveries between 76 % and 119 %Lucía Abad thanks to Universidad Autonoma ´ de Madrid for the predoctoral fellowship (FPI-UAM program). Sergio Lucas-Sanchez ´ acknowledges to Comunidad de Madrid and European Social Fund for the contracts PEJ-2018-AI/BIO-11845 through the Youth Employment Initiative (YEI

Electrochemical sensing platform with gold nanoparticles capped by PDDA for benzyl alcohol determination

An electrochemical sensor has been developed, by modifying screen-printed carbon devices (SPCE) with photochemically synthesized gold nanoparticles (AuNP), to determine benzyl alcohol, a preservative widely used in the cosmetic industry. To obtain the AuNP with the best properties for electrochemical sensing applications, the photochemical synthesis was optimized using chemometric tools. A response surface methodology based on central composite design was used to optimize the synthesis conditions, as irradiation time, and the concentrations of metal precursor and the capping/reducing agent (poly(diallyldimethylammonium) chloride, PDDA). The anodic current of benzyl alcohol on SPCE modified with the AuNP was used as response of the system. The best electrochemical responses were obtained using the AuNP generated by irradiating for 18 min a 7.20 × 10−4 mol L−1 AuCl4−-1.7% PDDA solution. The AuNP were characterized by transmission electron microscopy, cyclic voltammetry and dynamic light scattering. The nanocomposite-based sensor formed by the optimal AuNP (AuNP@PDDA/SPCE) was used to determine benzyl alcohol by linear sweep voltammetry in 0.10 mol L−1 KOH. The anodic current at + 0.017 ± 0.003 V (vs. AgCl) was used as analytical signal. Detection limit obtained under these conditions was 2.8 µg mL−1. The AuNP@PDDA/SPCE was applied to determine benzyl alcohol in cosmetic samplesOpen Access funding provided thanks to the CRUE-CSIC agreement with Springer Natur

Effect of hypoxia on lung gene expression and proteomic profile: insights into the pulmonary surfactant response

Exposure of lung to hypoxia has been previously reported to be associated with significant alterations in the protein content of bronchoalveolar lavage (BAL) and lung tissue. In the present work we have used a proteomic approach to describe the changes in protein complement induced by moderate long-term hypoxia (rats exposed to 10% O2 for 72h) in BAL and lung tissue, with a special focus on the proteins associated with pulmonary surfactant, which could indicate adaptation of this system to limited oxygen availability. The analysis of the general proteomic profile indicates a hypoxia-induced increase in proteins associated with inflammation both in lavage and lung tissue. Analysis at mRNA and protein levels revealed no significant changes induced by hypoxia on the content in surfactant proteins or their apparent oligomeric state. In contrast, we detected a hypoxia-induced significant increase in the expression and accumulation of hemoglobin in lung tissue, at both mRNA and protein levels, as well as an accumulation of hemoglobin both in BAL and associated with surface-active membranes of the pulmonary surfactant complex. Evaluation of pulmonary surfactant surface activity from hypoxic rats showed no alterations in its spreading ability, ruling out inhibition by increased levels of serum or inflammatory proteins.Ministerio de Ciencia BIO2012-30733Ministerio de Ciencia CSD2007-00010Gobierno de la Comunidad de Madrid S2009MAT-1507National Institutes of Health NIH HL3478

A MWCNTs-COOH/PSS nanocomposite–modified screen-printed electrode for the determination of synthetic phenolic antioxidants by HPLC with amperometric detection

New sensing platforms based on screen-printed carbon electrodes modifed with composites based on polystyrene sulfonate and oxidized multi-walled carbon nanotubes (PSS/MWCNTs-COOH/SPCE) have been used to develop a novel HPLC method with electrochemical detection (ECD) for the determination of the most used synthetic phenolic antioxidants in cosmetics: butylhydroxytoluene (BHT), butylhydroxyanisole (BHA), tert-butylhydroquinone (TBHQ) and propyl gallate (PG). Optimal separation conditions were achieved using methanol: 0.10 mol L−1 acetate solution at pH 6 as mobile phase with a gradient elution program from 60 to 90% of methanol percentage in 15 min. The electrochemical detection was carried out in amperometric mode using the PSS/MWCNTs-COOH/SPCE at+0.80 V vs. Ag. Under these optimal separation and detection conditions, the limits of detection (LOD) were between 0.11 and 0.25 mg L−1. These LOD values were better, especially for BHT, than those previously published in other HPLC methods. Linear ranges from 0.37 mg L−1, 0.83 mg L−1, 0.69 mg L−1 and 0.56 mg L−1 to 10 mg L−1 were obtained for PG, TBHQ, BHA and BHT, respectively. RSD values equal or lower than 5% and 8% were achieved for repeatability and reproducibility, respectively. The HPLC-ECD method was successfully applied to analyze diferent cosmetic samples. Recovery values within 83–109% were obtained in the validation studiesOpen Access funding provided thanks to the CRUE-CSIC agreement with Springer Natur

Disposable screen-printed carbon-based electrodes in amperometric detection for simultaneous determination of parabens in complex-matrix personal care products by HPLC

Parabens are chemicals widely used as preservatives in different types of industrial products. In recent years, the concern about the safety of these compounds has increased due to their endocrine disrupting activity. For this reason, their use is highly regulated and even some of them have already been banned. Thus, methods for the sensitive and selective detection of these compounds are required to control their presence in food, cosmetic, and pharmaceutical products. This paper presents an HPLC method with electrochemical detection using disposable screen-printed electrodes (SPE) for simultaneous determination of 6 different parabens in personal care products. Electrochemical behaviour of parabens was studied on SPE with different carbon-based materials as working electrode: carbon, ordered mesoporous carbon and graphene. From these studies, pH, detection potential, and the most adequate SPE were chosen. Due to the wide range of textures and viscosities (e.g., liquid, solid, and semi-solid) of personal care products, adequate sample pretreatments are required before chromatographic measurement. Here, a fast ultrasound-assisted extraction method was applied to simultaneously extract 6 parabens (methyl-, ethyl-, isopropyl-, propyl-, butyl-and benzyl-paraben) from different complex-matrix cosmetic products. Instrumental limits of detection between 20 and 115 μg L− 1 were obtained applying +1.0 V (vs. Ag) as detection potential on carbon-based SPE. The total analysis time, including sample extraction and HPLC run, was shorter than 35 min. The proposed method is more versatile and faster than the current available methods and has been successfully applied to determine parabens in commercial samples such as shampoos, body creams, facial tonics, and toothpastesLucia Abad acknowledges to Universidad Autonoma de Madrid for the predoctoral fellowship (FPI-UAM program). Sergio Lucas and Carmen Isabel thanks to Community of Madrid and European Social Fund for the contracts PEJ-2018-AI/BIO-11845 and PEJ-2019-TL/IND-14286, respectively through the Youth Employment Initiative (YEI

GC-TOF-MS metabolite profiling of drought tolerant Quercus ilex

Perfil metabólico primario de hojas de encina en respuesta al estrés hídrico por sequía

Diez años de selección de toros jóvenes en el centro de testaje de la raza Bruna dels Pirineus

publishedTomo I . Sección: Sistemas Ganaderos-Economía y Gestión. Sesión: Vacuno carne II. Ponencia nº

Pseudomonas guineae sp.nov, a novel psychrotolerant bacterium from an Antarctic environment

Two Gram-negative, cold-adapted, aerobic bacteria, designated strains M8T and M6, were isolated from soil collected from the South Shetland Islands. The organisms were rod-shaped, catalase- and oxidase-positive and motile by means of polar flagella. These two psychrotolerant strains grew between −4 and 30 °C. 16S rRNA gene sequence analysis placed strains M8T and M6 within the genus Pseudomonas. DNA–DNA hybridization experiments between the Antarctic isolate M8T and type strains of phylogenetically related species, namely Pseudomonas peli and Pseudomonas anguilliseptica, revealed levels of relatedness of 33 and 37 %, respectively. Strain M6 showed 99 % DNA similarity to strain M8T. Several phenotypic characteristics, together with data on cellular fatty acid composition, served to differentiate strains M8T and M6 from related pseudomonads. On the basis of the polyphasic taxonomic evidence presented in this study, it can be concluded that strains M8T and M6 belong to the same genospecies, representing a novel species of the genus Pseudomonas, for which the name Pseudomonas guineae sp. nov. is proposed. The type strain is M8T (=LMG 24016T=CECT 7231T)