339 research outputs found

    Distribution and structure of the southernmost Caribbean coral reefs: golfo de Urabá, Colombia

    Get PDF
    The Gulf of Urabá represents the southernmost portion of the Caribbean Sea. Due to the large amounts of sediment and freshwater discharged by the Atrato river and several minor streams, water conditions in the area are far from being optimal for coral settlement and growth. However, fringing and patch reefs are developed along the rocky shores of the northwest margin of the Gulf. Based on field observations performed at 44 sites (12 of them assessed quantitatively), interpretation of air photography of the area and depth profiles, the distribution, structure and zonation of the reefs are described. Classification analysis of the 12 sample sites yielded four coral assemblages: Diploria strigosa, crustose algae, Siderastrea siderea, Agaricia spp., and mixed massive corals. Other two assemblages, dominated respectively by Millepora complanata and thickets of Acropora palmata were noticed during reconnaissance dives. The distribution of these zones within the reef seems likely to be mainly controlled by wave exposure, bottom topography, sedimentation, and light penetration. Reef development, coral diversity and live coral cover increase along the coast in a SE-NW direction, with an evident maximum near to the cove of Sapzurro, suggesting an overall improvement of conditions for coral growth and settlement in that direction. A total of 33 species of hard corals were recorded during the survey. It is apparent that the live coral cover, particularly of foliose and branching species, has notably declined recently

    Solving the Location Area Problem by Using Differential Evolution

    Get PDF
    In mobile networks, one of the hard tasks is to determine the best partitioning in the Location Area problem, but it is also an important strategy to try to reduce all the involved management costs. In this paper we present a new approach to solve the location management problem based on the Location Area partitioning, as a cost optimization problem. We use a Differential Evolution based algorithm to find the best configuration to the Location Areas in a mobile network. We try to find the best values for the Differential Evolution parameters as well as define the scheme that enables us to obtain better results, when compared to classical strategies and to other authors’ results. To obtain the best solution we develop four distinct experiments, each one applied to one Differential Evolution parameter. This is a new approach to this problem that has given us good results

    ¿Apoyan los entrenadores la motivación de sus deportistas? Diferencias en la percepción del comportamiento

    Get PDF
    El objetivo de este trabajo era valorar la influencia de la percepción de apoyo a las necesidades psicológicas básicas (NPB) sobre la motivación intrínseca, disfrute, aburrimiento e intención de persistencia en el contexto deportivo de base, y como podía incidir la diferencia entre lo que los entrenadores creían proporcionar y lo que los deportistas percibían, en relación a dicho apoyo. Para ello, se llevaron a cabo 2 estudios diferentes. En el estudio 1 participaron 985 deportistas (M = 14,34; DT = 2,52) y se realizó un análisis de regresión, en el que se demostró la importancia de las percepciones de apoyo a las NPB sobre las variables analizadas. En función de estos resultados, se llevó a cabo el estudio 2, en el que participaron 91 entrenadores (M = 32,41; DT = 6,51) y 432 deportistas (M = 13,44; DT = 2,92), realizándose un análisis de diferencias entre grupos de entrenadores creados en función de la percepción de apoyo proporcionado y el apoyo percibido por los deportistas. Los resultados demostraron diferencias en la motivación intrínseca, aburrimiento e intención de persistencia entre los deportistas cuyos entrenadores creían proporcionar más apoyo a las NPB que el percibido por los atletas, respecto a aquellos cuyos entrenadores consideraban realizar un apoyo similar o inferior al percibido. Por tanto, los resultados hallados tienen implicaciones relevantes para explicar la adherencia deportiva en etapas de formación y en la consideración de los antecedentes motivacionales en el contexto deportivo.The aim of this study was focused on assessing the influence of perception of support for basic psychological needs (BPN) on variables such as intrinsic motivation, enjoyment, boredom, and intention to persist in the training sport context; and how this can affect the difference between what is provided and what coaches believe athletes perceive in relation to such support. To achieve this aim, two different studies were conducted. In the 1st study, 985 athletes participated (M = 14.34; SD = 2.52), and a regression analysis was performed, where the results showed the importance of perception of support for BPN in the variables analyzed. Regarding the outcomes found in the former section, the 2nd study was carried out, where 91 coaches (M = 32.41; SD = 6.51) and 432 athletes (M = 13.44; SD = 2.92) were involved, and an analysis of differences was conducted after the creation of groups of coaches formed with respect to the support given and the support perceived by athletes. The results show differences in intrinsic motivation, boredom and intention to persist between athletes whose coaches were believed to give more support for BPN than perceived by athletes, with respect to participants whose coaches were considered to give support similar to or lower than the perceived. Therefore, the outcomes found have relevant implications to explain sport adherence in training stages, as well as the consideration of motivational background in a sport context.O principal objectivo do presente estudo foi avaliar a influência da percepção de apoio às necessidades psicológicas básicas (NPB) em variáveis como a motivação intrínseca, divertimento, aborrecimento e intenção para persistir no treino desportivo, e como isso pode afectar as diferenças entre o que fornecem e o que pensam os treinadores que os atletas percepcionam no que concerne a esse apoio. Para alcançar este objectivo, foram desenvolvidos dois trabalhos. No primeiro estudo participaram 985 atletas (M = 14.34; DP = 2.52), e foi realizada uma análise de regressão sendo que os resultados demonstraram a importância da percepção de apoio às NPB nas variáveis analisadas. Tendo em conta os resultados obtidos no estudo anterior, o segundo estudo foi levado a cabo com a participação de 91 treinadores (M = 32.41; DP = 6.51) e 432 atletas (M = 13.44; DP = 2.92), e uma análise de diferenças efectuada após a criação de grupos de treinadores formados com base no critério de apoio prestado e o apoio percebido pelos atletas. Os resultados revelam diferenças na motivação intrínseca, aborrecimento e intenção de persistir entre atletas cujos treinadores acreditavam fornecer mais apoio pa as as NPB que o percepcionado pelos atletas, relativamente aos participantes cujos treinadores consideravam fornecer igual ou inferior apoio ao percepcionado. Contudo, os resultados obtidos apresentam implicações relevantes na explicação da adesão às etapas do treino desportivo, bem como relativamente à consideração de antecedentes motivacionais no contexto desportivo

    HIV self-testing in Spain: A valuable testing option for men-who-have-sex-with-men who have never tested for HIV

    Get PDF
    BACKGROUND: We assessed the capacity of HIV self-testing to promote testing among untested men who have sex with men (MSM) and determined the most benefited subpopulations. METHODS: An online questionnaire was disseminated on several gay websites in Spain from September 2012 to April 2013. We used Poisson regression to estimate factors associated with the intention to use self-testing if already available. Among those who reported intention of use, we assessed several aspects related to the testing and linkage to care process by type of barrier reported: low perceived risk (LR), structural barriers (SB) and fear of testing positive (FTP). RESULTS: Of 2589 never-tested MSM, 83% would have used self-testing if already available. Intention of use was associated with age ≥30 (adj.PR, 95%CI: 1.05, 1.01-1.10), having had protected (adj.PR, 95%CI: 1.15, 1.02-1.30) or unprotected (adj.PR, 95%CI: 1.21, 1.07-1.37) anal intercourse and reporting FTP (adj.PR, 95%CI: 1.12, 1.05-1.20) or SB to access HIV testing (adj.PR, 95%CI: 1.23, 1.19-1.28). Among those who reported intention of using a self-testi, 78.3% declared it their preferred option (83.8% in the SB group; p<0.001), and 56.8% would always use this testing option (60.9% among the SB group; p = 0.001). In the case of obtaining a positive self-test, 69.3% would seek confirmatory testing, 15.3% would self-test again before taking any decision and 13.0% reported not being sure of what they would do. CONCLUSION: HIV self-testing in Spain has the potential of becoming a highly used testing methodology for untested MSM and could represent the gateway to testing especially among older, at risk MSM who report SB or FTP as main barriers to testing.This study was funded by the Ministerio de Sanidad, Servicios Sociales e igualdad (https://www.msssi.gob.es/) (MSSSI EC11-279). Work by JP was also partially supported by "Ayuda Juan de la Cierva-Incorporación" (Grant number IJCI-2015-23261).S

    Dynamic procedure for daily PM56 ETo mapping conducive to site-specific irrigation recommendations in areas covered by agricultural weather networks.

    Full text link
    [EN] Modern agriculture is underpinned by actual meteorological data registered using automated meteorological stations forming networks specifically created for advising purposes. In many cases, those data used to be accessible online by means of APIs (Application Programming Interface). One of the most common cases is the irrigation-advice weather network implemented with the aim of obtaining ETo values to be used in irrigation recommendations. However, those punctual values of ETo scattered throughout the territory do not allow to produce specific irrigation recommendations for each farm. The only way of disposing site-specific values of ETo is by compiling maps that describe its spatial variation. With this objective, a new dynamic procedure based on an existing regression-based technique of interpolation was proposed. Using the meteorological data registered at the end of each day, maximum and minimum temperature, maximum and minimum relative humidity, wind velocity, and radiation maps were interpolated and then, an ETo map was derived. The proposed procedure demonstrated a special adaptation capacity to the synoptic pattern of each day using some geographical features or others, as appropriate to explain the spatial variability of the interpolated meteorological variable. In those months where radiation plays a key role in the ETo value (growing season), ETo maps obtained were especially fine-grained in areas with significant relief. This procedure improved other contrasted methodologies they were compared with. The impact of using the nearest-weather-station ETo vs interpolated value on a daily water needs was investigated and near 10% average value of error was encountered in the case study.This study has received funding from the eGROUNDWATER project (GA n. 1921) , part of the PRIMA program supported by the European Union 's Horizon 2020 research and innovation program, and the WATER4CAST project (PROMETEO/2021/074) , which is funded by the Conselleria de Innovacion, Universidades, Ciencia y Sociedad Digital de la Comunitat Valenciana.Meteorological data were provided by SIAR: " Sistema de Informacion Agroclimatica para el Regadio. Ministerio de Agricultura, Pesca y Alimentacion" . Special thanks to Carlos Garrido Garrido and Ivan Cilleros Fuentetaja for providing us an API-SIAR access. Thanks to Luis Bonet for giving us permission to use the picture of the IVIA-SIAR automated station.Garcia-Prats, A.; Carricondo-Antón, JM.; Jiménez Bello, MA.; Manzano Juarez, J.; López Pérez, E.; Pulido-Velazquez, M. (2023). Dynamic procedure for daily PM56 ETo mapping conducive to site-specific irrigation recommendations in areas covered by agricultural weather networks. Agricultural Water Management. 287:1-18. https://doi.org/10.1016/j.agwat.2023.10841511828

    Evolutionary Computation and QSAR Research

    Get PDF
    [Abstract] The successful high throughput screening of molecule libraries for a specific biological property is one of the main improvements in drug discovery. The virtual molecular filtering and screening relies greatly on quantitative structure-activity relationship (QSAR) analysis, a mathematical model that correlates the activity of a molecule with molecular descriptors. QSAR models have the potential to reduce the costly failure of drug candidates in advanced (clinical) stages by filtering combinatorial libraries, eliminating candidates with a predicted toxic effect and poor pharmacokinetic profiles, and reducing the number of experiments. To obtain a predictive and reliable QSAR model, scientists use methods from various fields such as molecular modeling, pattern recognition, machine learning or artificial intelligence. QSAR modeling relies on three main steps: molecular structure codification into molecular descriptors, selection of relevant variables in the context of the analyzed activity, and search of the optimal mathematical model that correlates the molecular descriptors with a specific activity. Since a variety of techniques from statistics and artificial intelligence can aid variable selection and model building steps, this review focuses on the evolutionary computation methods supporting these tasks. Thus, this review explains the basic of the genetic algorithms and genetic programming as evolutionary computation approaches, the selection methods for high-dimensional data in QSAR, the methods to build QSAR models, the current evolutionary feature selection methods and applications in QSAR and the future trend on the joint or multi-task feature selection methods.Instituto de Salud Carlos III, PIO52048Instituto de Salud Carlos III, RD07/0067/0005Ministerio de Industria, Comercio y Turismo; TSI-020110-2009-53)Galicia. Consellería de Economía e Industria; 10SIN105004P

    Factores condicionantes de la sostenibilidad como una dimensión estratégica del desarrollo turístico mexicano

    Get PDF
    This paper proposes the Delphi analysis to identify and analyze the key factors of sustainability in Mexicoʼs present tourism-development model. The importance of the results is due to the fact that sustainability has become a central aspect in the competitiveness of any tourism destination. In this sense, Mexicoʼs current shortfalls may limit the role of tourism in the economic development of the country. So, the definition of the sustainability factors in Mexico leads to the design and implementation of strategies to overcome such situation.A través del análisis Delphi, en este trabajo se identifican y analizan los principales condicionantes de la sostenibilidad del actual modelo de desarrollo turístico mexicano. La importancia de los resultados obtenidos radica en que la sostenibilidad se ha convertido en un factor clave en la capacidad de competir de cualquier destino turístico, y México presenta actualmente serios déficit en este aspecto, lo que, a su vez, puede constreñir la contribución del turismo al desarrollo económico del país. De ahí que conocer los factores que condicionan la sostenibilidad del turismo mexicano contribuya al diseño e implementación de estrategias para superar esta situación

    Enseñanza de Arquitecturas de Memorias Caché mediante Simuladores

    Get PDF
    En este trabajo se presentan dos experiencias docentes en la enseñanza de arquitecturas de memoria caché para la titulación de Ingeniería Informática de la Universidad de Extremadura. Estas experiencias se desarrollan desde dos puntos de vista: Sistemas caché multinivel para una asignatura de carácter fundamental ("Estructura de Computadores"), y sistemas de memoria caché en multiprocesadores, para una asignatura de carácter avanzado ("Arquitectura de Computadores")

    La asignatura AIC y su adaptación al EEES

    Get PDF
    La asignatura Arquitectura e Ingeniería de Computadores (AIC), impartida en la Universidad de Extremadura (UEx), pertenece al plan de estudios de la titulación de Ingeniería en Informática. Los autores presentan una propuesta de adaptación de dicha asignatura al Espacio Europeo de Educación Superior (EEES), con el ánimo de darla a conocer a otros profesores, y buscando siempre el intercambio de ideas y experiencias. En este artículo se detallan aspectos como las competencias que se pretenden fomentar con la asignatura AIC, la interrelación de AIC con otras asignaturas actuales en la titulación, los contenidos que se proponen para la asignatura teniendo en cuenta su adaptación al EEES, la dedicación que implicaría en créditos ECTS tanto para el alumno como para el profesor, las actividades e instrumentos de evaluación propuestos, etc
    corecore