426 research outputs found

    On the use of nestedness-based similarity functions (NBSF) to classify and/or order operational geographic units (OGUs)

    Get PDF
    Abstract In this paper, we want to support the idea of using a family of indices of similarity, that we call the Simpson's family indices or nestedness-based similarity functions (NBSF) for comparing operational geographic units (OGUs) (phytosociological relevés, animal traps, watersheds, administrative units, industrial areas, islands etc.). In these cases, similarity-dissimilarity depends, in addition to factors that induce replacement, also on factors that produce reduction or increment in the number of features within the same typology of OGUs (e.g., extent, reduction of fertility, anthropogenic pressure etc.). To keep into consideration this aspect, the indices are defined to be equal to 1 when the OGUs are completely nested. The results of the application to four simulated data sets prove that, when the data set does not show clear nested pattern, the use of NBSF produces results similar to the nestedness-free similarity functions, however since NBSF clearly detect nested situations, we should prefer their use in the circumstances where we think important to put in evidence nestedness. In conclusion, we support the idea of using both types of indices in order to improve the knowledge about the structure of any data set

    Using spatial data mining to analyze area-diversity patterns among soil, vegetation, and climate: A case study from Almería, Spain

    Get PDF
    ABSTRACT: Area-pedodiversity, area?vegetation diversity, area-bioclimatic belts, diversity and pedodiversity-vegetation diversity-bioclimatic diversity relationships were analyzed for the most arid region ofWestern Europe (SE Spain). The study is novel in that it analyzed these relationships using as operational geographic units (OGUs) the set of polygons belonging to the same character state (i.e., typology) that defines a zone in a given thematic map. We considered three thematic maps: 1) the map of soil associations (SMU) with 303 different soil associations (i.e., 303 areas or zones); 2) the map of potential vegetation (PNV)with 40 vegetation series or zones and 3) the map of bioclimatic belts (BB) with 7 bioclimatic zones. Using GIS tools, we analyzed the contents (richness) of soil mapping units (polygons) with regard to vegetation series and bioclimatic belts as well as the contents of vegetation series and bioclimatic belts with regard to SMU. The results indicate that the relationships between the area and the richness of zones follow a power law, the ?fingerprint of fractal geometry?, irrespective of the way the area has been defined and their relative magnitude (the areas defined by SMU are the smallest, while the areas defined by bioclimatic belts are the largest). The results also indicate a significant correlation between the ? diversities of the zones and between their ? diversities. We conclude that the methods used to measure such correlations, based on ? and ? diversities are useful to investigate and quantify the relationships between the pedosphere, vegetation and climate

    High--Resolution 3D Simulations of Relativistic Jets

    Full text link
    We have performed high-resolution 3D simulations of relativistic jets with beam flow Lorentz factors up to 7, a spatial resolution of 8 cells per beam radius, and for up to 75 normalized time units to study the morphology and dynamics of 3D relativistic jets. Our simulations show that the coherent fast backflows found in axisymmetric models are not present in 3D models. We further find that when the jet is exposed to non-axisymmetric perturbations, (i) it does not display the strong perturbations found for 3D classical hydrodynamic and MHD jets (at least during the period of time covered by our simulations), and (ii) it does propagate according to the 1D estimate. Small 3D effects in the relativistic beam give rise to a lumpy distribution of apparent speeds like that observed in M87. The beam is surrounded by a boundary layer of high specific internal energy. The properties of this layer are briefly discussed.Comment: 15 pages, 4 figures. Accepted to be publish in the ApJ Letters. Tar+gzip documen

    Basketball game-related statistics that discriminate between teams season-long success

    Get PDF
    The aim of the present study was to identify the game-related statistics that discriminate between season-long successful and unsuccessful basketball teams participating in the Spanish Basketball League (LEB1). The sample included all 145 average records per season from the 870 games played between the 2000-2001 and the 2005-2006 regular seasons. The following game-related statistics were gathered from the official box scores of the Spanish Basketball Federation: 2- and 3-point field-goal attempts (both successful and unsuccessful), free-throws (both successful and unsuccessful), defensive and offensive rebounds, assists, steals, turnovers, blocks (both made and received), and fouls (both committed and received). To control for season variability, all results were normalized to minutes played each season and then converted to z-scores. The results allowed discrimination between best and worst teams' performances through the following game-related statistics: assists (SC=0.47), steals (SC=0.34), and blocks (SC=0.30). The function obtained correctly classified 82.4% of the cases. In conclusion, season-long performance may be supported by players' and teams' passing skills and defensive preparation

    Environmental assessment of an animal fat based biodiesel: Defining goal, scope and life cycle inventory

    Get PDF
    The energy crisis and environmental problems have resulted in an increase of biofuels production. How- ever, the production cost is the biggest commercialization drawback for fuels such as biodiesel; the high- est cost in its production chain is associated with the raw material. Biodiesel is usually produced from vegetable oils; nevertheless, water supplies, fertilizers and large land areas are required for its produc- tion. An alternative is to use animal fat as the most economic raw material for biodiesel production. It does not compete with food safety and reduces the environmental impact caused by an inadequate dis- posal. But the use of biodiesel causes damages on some different parts of unmodified diesel engines and decrease their performance. Therefore, it is necessary to study additives that modify the thermodynamic and transport properties of biodiesel such as density, viscosity or surface tension. The aim of this research is to present the goal, scope and life cycle inventory necessary to evaluate the potential environmental impacts of ternary diesel + biodiesel + additives blends, as biofuels through life cycle assessment. Mass of reagents and blends components were identified, while they have already been tested and validated from the experimental data. The life cycle scenarios will include beef tallow, biodiesel, diesel and addi- tives production, mixing processes, and blends combustion

    Electrophysiological correlates of dispositional mindfulness: A quantitative and complexity EEG study

    Get PDF
    While growing evidence supports that dispositional mindfulness relates to psychological health and cognitive enhancement, to date there have been only a few attempts to characterize its neural underpinnings. In the present study, we aimed at exploring the electrophysiological (EEG) signature of dispositional mindfulness using quantitative and complexity measures of EEG during resting state and while performing a learning task. Hundred twenty participants were assessed with the Five Facet Mindfulness Questionnaire and underwent 5 min eyes-closed resting state and 5 min at task EEG recording. We hypothesized that high mindfulness individuals would show patterns of brain activity related to (a) lower involvement of the default mode network (DMN) at rest (reduced frontal gamma power) and (b) a state of ‘task readiness’ reflected in a more similar pattern from rest to task (reduced overall q-EEG power at rest but not at task), as compared to their low mindfulness counterparts. Dispositional mindfulness was significantly linked to reduced frontal gamma power at rest and lower overall power during rest but not at task. In addition, we found a trend towards higher entropy during task performance in mindful individuals, which has recently been reported during mindfulness meditation. Altogether, our results add to those from expert meditators to show that high (dispositional) mindfulness seems to have a specific electrophysiological pattern characteristic of less involvement of the DMN and mind-wandering processes.The current research was financially supported by the Spanish Ministry of Science, Innovation and Universities and the Andalusian Government (Fondos FEDER) grants: doctoral research grant ES-2016-078667 to NA, PSI2015-65502-C2-2-P to CG-A and A-CTS-111-UGR18, PGC2018-093786-B-I00, and PID2021-127728NB-100 to TB. Funding for open acces charge: Universdad de Granada / CBUA

    Mechanistic studies of the palladium-catalyzed S,O-ligand promoted C-H olefination of aromatic compounds

    Get PDF
    Pd-catalyzed C-H functionalization reactions of non-directed substrates have recently emerged as an attractive alternative to the use of directing groups. Key to the success of these transformations has been the discovery of new ligands capable of increasing both the reactivity of the inert C-H bond and the selectivity of the process. Among them, a new type of S,O-ligand has been shown to be highly efficient in promoting a variety of Pd-catalyzed C-H olefination reactions of non-directed arenes. Despite the success of this type of S,O-ligand, its role in the C-H functionalization processes is unknown. Herein, we describe a detailed mechanistic study focused on elucidating the role of the S,O-ligand in the Pd-catalyzed C-H olefination of non-directed arenes. For this purpose, several mechanistic tools, including isolation and characterization of reactive intermediates, NMR and kinetic studies, isotope effects and DFT calculations have been employed. The data from these experiments suggest that the C-H activation is the rate-determining step in both cases with and without the S,O-ligand. Furthermore, the results indicate that the S,O-ligand triggers the formation of more reactive Pd cationic species, which explains the observed acceleration of the reaction. Together, these studies shed light on the role of the S,O-ligand in promoting Pd-catalyzed C-H functionalization reactions.</p

    Virtual Environments and Augmented Reality Applied to Heritage Education. An Evaluative Study

    Get PDF
    Technological advancements have provided heritage with new learning environments via the use of virtual and augmented reality, which can foster the accessibility and understanding of culture and propose new ways of interacting with heritage. Therefore, in this study, a systematic evaluation is carried out of n=197 heritage education programs listed in the database of the Observatorio de Educaci&oacute;n patrimonial en Espa&ntilde;a (OEPE) (the Spanish Heritage Education Observatory&ndash;SHEO) which, in their descriptions, integrate the use of virtual environments and/or augmented reality to promote learning on the part of the user. The objectives of this study are: (1) to analyse the state of the art, (2) to evaluate the quality of their educational designs via the &ldquo;analysis and assessment sequential method for heritage education programs&rdquo; (SAEPEP-OEPE) and (3) to identify variables which can be improved or which have a significant influence on the quality of the programs. Highlights of the results include: (a) the increasing implementation of these technologies in heritage education programs, with the greater presence of virtual resources than of learning environments, (b) the low level of the scope of educational quality in their designs, particularly their assessment, and (c) the inclusion of advanced technologies slightly decreases the specificity of the educational design.This research was carried out with the aid of funding from the Spanish Ministry of Science, Innovation and Universities, and was co-funded by ERDF funds from the European Union for the research projects EDU2015-65716-C2-1-R, EDU2015-65716-C2-2-R, and PGC2018-094491-B-C33. It has also been made possible by funding from the Fundación Séneca of the Region of Murcia for the project 20638/JLI/18 and the Education Department of the Regional Government of the Basque Country (IT1193-19)

    Las mil y una noches. Español

    Get PDF
    En el texto impreso, página 7, figura "A la memoria del pensador poeta Stéfane Mallarmé esta obra que él tanto amaba. Enero 1899"

    Study of internal and external load by different instruments: A case study in grassroots

    Get PDF
    [Resumen] Los dispositivos tecnológicos utilizados actualmente para registrar carga externa e interna no son accesibles al fútbol formativo por su alto coste económico. Por ello, herramientas para cuantificar la carga y categorizar las tareas son muy útiles para el proceso de entrenamiento. Por tanto, los objetivos del presente trabajo son: (1) identificar las diferencias en la carga objetiva en función de las variables de carga externa subjetiva y (2) analizar la relación entre ambos métodos de cuantificación. 157 tareas realizadas por un equipo de 20 jugadores juveniles fueron analizadas. La recogida de datos se realizó mediante: (a) carga objetiva, dispositivos inerciales WIMUTM y (b) carga subjetiva, Sistema Integral para el Análisis de las Tareas de Entrenamiento (SIATE). El análisis estadístico estuvo compuesto por ANOVA de un factor con el post-hoc Bonferroni y la prueba de correlación de Pearson. Los principales resultados indican que existe influencia de las variables de carga subjetiva en las variables de carga objetiva (p.05), encontrando una alta correlación entre ellas (r>.84). Las características de las tareas modifican de forma directa las demandas de carga, siendo herramientas subjetivas como SIATE útiles para su registro ante la ausencia de material tecnológico.[Abstract] The technological devices utilized currently for the external and internal load register are not accessible in grassroots due to their high costs. Thus, tools for load quantification and tasks categorization are very useful to improve the training process. Therefore, the aims of the present study are to: (1) identify the differences between objective load of training tasks in relation to subjective external load variables and (2) analyse the relationship between both load quantification methods. 157 tasks performed by an 18-players youth soccer team were analysed. The load register was realised by: (a) objective load, WIMUTM inertial devices and (b) subjective load, Integral System for Training Tasks Analysis (SIATE). The statistical analysis was composed by one-way ANOVA with Bonferroni post-hoc and Pearson correlation test. The main results indicate that exist an influence of subjective load variables in objective load variables (p.05), finding a high correlation between loads (r>.84). The task characteristics directly modify the load demands, being subjective tools as SIATE useful for their register when technological devices are not availableJunta de Extremadura; GR1817
    corecore