Sparse Similarity and Network Navigability for Markov Clustering Enhancement

Markov clustering (MCL) is an effective unsupervised pattern recognition algorithm for data clustering in high-dimensional feature space that simulates stochastic flows on a network of sample similarities to detect the structural organization of clusters in the data. However, it presents two main drawbacks: (1) its community detection performance in complex networks has been demonstrating results far from the state-of-the-art methods such as Infomap and Louvain, and (2) it has never been generalized to deal with data nonlinearity. In this work both aspects, although closely related, are taken as separated issues and addressed as such. Regarding the community detection, field under the network science ceiling, the crucial issue is to convert the unweighted network topology into a ‘smart enough’ pre-weighted connectivity that adequately steers the stochastic flow procedure behind Markov clustering. Here a conceptual innovation is introduced and discussed focusing on how to leverage network latent geometry notions in order to design similarity measures for pre-weighting the adjacency matrix used in Markov clustering community detection. The results demonstrate that the proposed strategy improves Markov clustering significantly, to the extent that it is often close to the performance of current state-of-the-art methods for community detection. These findings emerge considering both synthetic ‘realistic’ networks (with known ground-truth communities) and real networks (with community metadata), even when the real network connectivity is corrupted by noise artificially induced by missing or spurious links. Regarding the nonlinearity aspect, the development of algorithms for unsupervised pattern recognition by nonlinear clustering is a notable problem in data science. Minimum Curvilinearity (MC) is a principle that approximates nonlinear sample distances in the high-dimensional feature space by curvilinear distances, which are computed as transversal paths over their minimum spanning tree, and then stored in a kernel. Here, a nonlinear MCL algorithm termed MC-MCL is proposed, which is the first nonlinear kernel extension of MCL and exploits Minimum Curvilinearity to enhance the performance of MCL in real and synthetic high-dimensional data with underlying nonlinear patterns. Furthermore, improvements in the design of the so-called MC-kernel by applying base modifications to better approximate the data hidden geometry have been evaluated with positive outcomes. Thus, different nonlinear MCL versions are compared with baseline and state-of-art clustering methods, including DBSCAN, K-means, affinity propagation, density peaks, and deep-clustering. As result, the design of a suitable nonlinear kernel provides a valuable framework to estimate nonlinear distances when its kernel is applied in combination with MCL. Indeed, nonlinear-MCL variants overcome classical MCL and even state-of-art clustering algorithms in different nonlinear datasets. This dissertation discusses the enhancements and the generalized understanding of how network geometry plays a fundamental role in designing algorithms based on network navigability

Virtual Screening of Plant Volatile Compounds Reveals a High Affinity of Hylamorpha elegans (Coleoptera: Scarabaeidae) Odorant-Binding Proteins for Sesquiterpenes From Its Native Host

Indexación: Web of ScienceHylamorpha elegans (Burmeister) is a native Chilean scarab beetle considered to be a relevant agricultural pest to pasture and cereal and small fruit crops. Because of their cryptic habits, control with conventional methods is difficult; therefore, alternative and environmentally friendly control strategies are highly desirable. The study of proteins that participate in the recognition of odorants, such as odorant-binding proteins (OBPs), offers interesting opportunities to identify new compounds with the potential to modify pest behavior and computational screening of compounds, which is commonly used in drug discovery, may help to accelerate the discovery of new semiochemicals. Here, we report the discovery of four OBPs in H. elegans as well as six new volatiles released by its native host Nothofagus obliqua (Mirbel). Molecular docking performed between OBPs and new and previously reported volatiles from N. obliqua revealed the best binding energy values for sesquiterpenic compounds. Despite remarkable divergence at the amino acid level, three of the four OBPs evaluated exhibited the best interaction energy for the same ligands. Molecular dynamics investigation reinforced the importance of sesquiterpenes, showing that hydrophobic residues of the OBPs interacted most frequently with the tested ligands, and binding free energy calculations demonstrated van der Waals and hydrophobic interactions to be the most important. Altogether, the results suggest that sesquiterpenes are interesting candidates for in vitro and in vivo assays to assess their potential application in pest management strategies.http://jinsectscience.oxfordjournals.org/content/16/1/3

Autocompasión e imagen corporal: vivencias y significados en mujeres adultas Chilenas. Un estudio cualitativo/Self-compasion and body image: experiences and meanings in Chilean adult women. A qualitative study

 El presente estudio explora la relación entre autocompasión e imagen corporal a partir de las vivencias y los significados reportados por mujeres chilenas. Se exploró mediante una metodología cualitativa, se realizaron entrevistas semi-estructuradas a ocho mujeres normopeso entre 20 y 30 años de Chile. Los datos fueron analizados en base a la perspectiva de la teoría fundamentada. Tras el análisis descriptivo se dio cuenta de los siguientes fenómenos: (1) la apreciación corporal depende de la complexión física, la que es variable; (2) las mujeres presentan dificultad para relacionarse amablemente con su cuerpo; (3) cuando se conocen, quieren y aceptan son más autocompasivas con su cuerpo; y (4) llevar una vida saludable ayuda a tener una mayor autocompasión. A pesar de que a las mujeres les resulta fácil reconocer la insatisfacción corporal, se les hace especialmente difícil aliviarla de manera amable. Una forma de lograr aliviar más autocompasivamente es aumentando el autoconocimiento, la aceptación, el amor, la confianza y la seguridad en sí mismas; como una forma de protegerse ante las exigencias impuesta

Expresión escrita y comunicación en los actuales programas del Ministerio de Educación Publica

libro--Universidad de Costa Rica, Sede de Occidente, 1992. Edición mimeografiadaEl trabajo surgió como respuesta a la necesidad que presentaba el sistema educativo costarricense, con relación a la desactualización de los programas educativos en cuanto a enfoque y contenidos. Era necesario que los programas de estudio fueran funcionales de acuerdo con la realidad del país y que removieran la concepción del docente y alumno, en busca de una educación que fomentara en los estudiantes la creatividad, reflexión y la criticidad, con el fin de que se dinamice el proceso enseñanza-aprendizaje, de acuerdo con los temas de educación y expresión escrita. Se presentan los siguientes temas: el proceso comunicativo, el aparato fonador, los procesos narrativo y descriptivo y un análisis de la publicidad. Además, la carta, el acta, las fichas y la encuesta (entrevista y cuestionario, además de ser tratados en sus aspectos teóricos se presentan con ejemplos prácticos. Finalmente se presenta una referencia a los verbos fáciles con el fin de exhortar a los lectores a no abusar de estos.Universidad de Costa Rica, Sede de Occidente, Coordinación de Investigación.UCR::Sedes Regionales::Sede de Occident

La insistencia institucional: consideraciones teóricas acerca de la psicología política. / Institutional insistence: Theoretical considerations about political psychology.

El presente artículo examina teóricamente las vinculaciones existentes entre argumentos desarrollados por la psicología política y una noción de “institución” de carácter dinámica. En dicha conexión se argumenta sobre la importancia de incorporar al análisis de los procesos investigativos e interventores la noción de “lo político”, en la medida que propicia aperturas para generar nuevas estrategias de trabajo en contextos institucionales, desde la misma psicología política. This paper theoretically examines the links between arguments developed by political psychology and a notion of “institution” dynamic character. In this connection it is argued about the importance of incorporating the analysis of the investigative processes and intervenors the notion of “political”, to the extent that favors openings to generate new work strategies, from the same political psychology

Implementing a Distance Estimator for a Wildlife Tracking System Based on 802.15.4

In this work, a novel distance estimation mechanism using received signal strength indication (RSSI) signals with ZigBee modules is designed, implemented and tested in several scenarios. This estimator was used for a research project focused on a wildlife behavioral classification system deployed in Doñana’s National Park. As a supporting feature for that project, this work was implemented for locating animal’s collars acting as wireless nodes in order to find those who went outside of the coverage area of the network or that were accidentally detached from animals. This work describes the system architecture and the implementation of a mobile assistant capable of recovering devices located beyond the coverage of the network. The analytical model needed for distance estimation and the signal filtering are described, as well as the difficulties that the researchers must deal when building robust location estimators. This theoretical model was applied to three different scenarios and tested with two validation experiments.Junta de Andalucía P12-TIC-130

High LDL levels are associated with increased lipoprotein-associated phospholipase A(2) activity on nitric oxide synthesis and reactive oxygen species formation in human endothelial cells

Objective: To evaluate in vitro the effects of serum and LDL fractions isolated from hypercholesterolemic patients on nitric oxide (NO) synthesis and reactive oxygen species (ROS) production by human umbilical vein endothelial cells (HUVECs). Design and methods: Serum and LDL isolated from subjects with high (n=18) and normal (n=21) LDL-cholesterol levels were analyzed on NO synthesis and ROS production in vitro models of HUVECs. LDL was furthers characterized in their chemical composition and activities of lipoprotein-associated phospholipase A(2) (Lp-PLA(2)), cholesteryl ester transfer protein (CETP) and paraoxonase. Results: NO bioavailability was significantly lower and ROS production higher in HUVECs incubated with serum samples from patients with high LDL-cholesterol levels in comparison to control subjects. Moreover, hypercholesterolemic patients presented higher CETP and Lp-PLA(2) activities than control subjects. LDL fractions isolated from patients and controls were not different in their chemical composition, Lp-PLA(2) activity, and their capacity to reduce NO synthesis and increase ROS production. Conclusion: Alterations of serum from hypercholesterolemic patients could be due to the increment in LDL concentration, main Lp-PLA(2) carrier, and not to LDL composition or intrinsic Lp-PLA(2) activity

Construcción y ensayo de piranómetros fotovoltaicos de bajo costo desarrollados en la C.N.E.A.

Los piranómetros construidos utilizan como elemento sensor una celda fotovoltaica de silicio cristalino, con dos tipos de cubierta, una de vidrio transparente y otra de vidrio esmerilado. Se midió la respuesta angular de los piranómetros, variando el ángulo de incidencia de la luz en ±90°, y se la comparó con la ley del coseno. Se estudió en condiciones reales el comportamiento de uno de los sensores con difusor, comparándoselo con un piranómetro termoeléctrico de precisión, regularmente utilizado para la calibración de otros solarímetros. Se analizaron tanto las integrales diarias cuanto las horarias, determinándose la constante media diaria de calibración mediante el ajuste de una correlación lineal que arrojó un coeficiente de determinación de 0,99, comparable al obtenido para otros sensores fotovoltaicos ya comercializados en el exterior.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES