Estudio ecológico del ecosistema cavernícola de una sima de origen volcánico

[cat] En el present article es fa un estudi ecològic d'un avenc volcànic (Sima Robada, Tenerife, Illes Canàries), analitzant-se primerament I'orígen d'aquestes formacions geològiques, així com les influències que la seva particular morfologia té sobre la fauna. També es descriuen els fluxes energètics d'entrada i la manera corn s'organitzen les espècies cavernícoles en funció d'aquells, arribant a la conclusió de que, per les seves característiques, la comunitat cavernícola de la Sima Robada s'assembla més a les de tipus tropical que no pas a les de climes temperats. Finalment s'estableixen, per una banda, associacions entre aquestes espècies i les d'altres coves de Tenerife, elaborant-se algunes teories al voltant de les causes que influeixen en la distribució subterrània de les especies troglobies.[eng] In this article we present an ecological study of a volcanic pit (Sima Robada, Tenerife, Canary Islands), analysing in the first place the origin of these geological formations and the effects of their particular morphology on the fauna. We also describe the energy input and how the cave species relate to this, and conclude that in its structure the cave community of the Sima Robada more closely resembles the communities of tropical caves than those of temperate zones. Finally, we establish on the one hand associations among the species of the pit, and on the other hand the relationships that exist between these species and those of other caves in Tenerife, drawing various conclusions concerning the factors that are influential in the subterranean distribution of troglobite species

A review of river habitat characterisation methods: indices vs. characterisation protocols

RESUMEN. Una gran variedad de metodologías se han propuesto para la caracterización de los hábitats fluviales a fin de cumplir con diferentes objetivos medioambientales. Esta diversidad de métodos puede ser vista como una ventaja para hacer frente a diferentes objetivos ambientales. Sin embargo, el seguimiento a medio o largo plazo de las características físicas del hábitat fluvial carece de una metodología estandarizada, lo cual contrasta con otros métodos mucho mejor establecidos para el seguimiento de otros componentes del ecosistema fluvial. Se han hecho algunos intentos para estandarizar los métodos de caracterización de los hábitats fluviales, y estos incluyen el estándar europeo para la evaluación de las características hidromorfológicas de los ríos (CEN, 2002), y el desarrollo del módulo de evaluación fisicoquímica dentro del sistema australiano de evaluación fluvial (AusRivAS). Uno de los primeros pasos para avanzar en el desarrollo y uso de métodos para la caracterización de los hábitats fluviales en los programas de seguimiento a medio y largo plazo es revisar las prácticas actuales a fin de poder abordar las deficiencias e introducir mejoras. En el presente trabajo se revisan más de 50 métodos que se han utilizado para caracterizar los hábitats fluviales en todo el mundo, utilizando el estándar europeo como referencia para comparar los métodos. Los métodos de caracterización de los hábitats fluviales se diferencian principalmente por tres razones: (1) los objetivos para los que fueron diseñados, (2) el tiempo que demanda su aplicación y (3) unos miden mientras otros evalúan las características del hábitat. Las características del cauce y de la zona ribereña son consideradas por un mayor número de métodos que las características de la llanura de inundación. Además, entre todas las características del hábitat fluvial descritas, la estabilidad de las orillas, el sustrato del lecho, las estructuras artificiales, la estructura de la vegetación ribereña, las dimensiones del cauce, el tipo de flujo o el caudal, los usos del suelo adyacentes y las barras de sedimentos son las más comúnmente registradas. Se concluye que los métodos de medición de las características del hábitat fluvial que recogen información cuantitativa cubriendo diferentes escalas espaciales podrían ser los más eficaces, ya que proporcionan bases de datos más amplias que permiten utilizar la información para diversos objetivos. Por último, algunos tipos de ríos, como los ríos intermitentes, requieren un mayor estudio para poder identificar correctamente los atributos físicos y la metodología adecuada para realizar el seguimiento de las características del hábitat.ABSTRACT. A wide variety of methodologies have been proposed for characterising river habitats in order to meet different environmental objectives. However, mid- to long-term monitoring of the physical characteristics of river habitats lacks a standardised methodology. This contrasts with well-established methods for monitoring other river ecosystem components. Some attempts have been made to standardise the methods for characterising river habitats including the European Guidance Standard for Assessing the Hydromorphological Characteristics of Rivers (CEN, 2002) and the Physical and Chemical AssessmentModule within the Australian River Assessment System (AusRivAS). One of the first steps toward advancing the development and use of methods for characterising river habitats in mid- to long-term monitoring programs is to review current practices so that deficiencies can be identified and addressed. In the present work, we review more than 50 methods that have been used to characterise river habitats worldwide. This review uses the European standard as a reference benchmark for comparison with existing methods of river habitat characterisation. Methods of characterising river habitats differ mainly with respect to three features: (1) the objectives for which they were designed, (2) the time required for their application and (3) whether they measure characteristics or evaluate them. Channel and riparian zone characteristics are more extensively covered than floodplain characteristics. Moreover, of all the described river habitat characteristics, bank stability, channel substrate, artificial structures, riparian vegetation structure, channel dimensions, flow types or flow status, adjacent land uses and bars are the most commonly recorded.We conclude that assessment methods of river habitat characteristics that gather quantitative information at a range of spatial scales could be the most effective, as they provide relatively extensive data sets that can be used to analyse information for several purposes. Finally, some types of rivers, such as intermittent rivers, require further work in order to identify their physical habitat characteristics and the proper monitoring methodology

A comparison of modeling techniques to predict hydrological indices in ungauged rivers

Predicting the natural flow regime in ungauged rivers is an important challenge in water resource management and ecological research. We developed models to predict 16 hydrological indices in a river network covering the northern third of the Iberian Peninsula. Multiple Linear Regression (MLR), Generalized Additive Models (GAMs), Random Forest (RF) and Adaptive Neuro Fuzzy Inference System (ANFIS) were used and compared according to their prediction accuracy. The results showed that predictive performance varied greatly depending on the modeled hydrological attribute. The magnitude and frequency indices were predicted with excellent accuracy. In contrast, no technique was capable of developing precise models for hydrological indices of timing, duration and rate of change. This is mainly related to the lack of proper environmental databases on the scales on which these flow regime patterns are influenced. In addition, complex modeling techniques did not always outperform linear models and no single approach was optimal for all indices. ANFIS and GAMs provided the best results; however, other issues such as computational cost and the level of knowledge required to apply the method and interpret the results should be taken into account.This study was partly funded by the Spanish Ministry of Economy and Competitiveness as part of the HYDRA (Ref. BIA2015-71197) and RIVERLANDS (Ref. BIA2012-33572) projects

A cross-cultural re-evaluation of the Exercise Addiction Inventory (EAI) in five countries

Research into the detrimental effects of excessive exercise has been conceptualized in a number of similar ways, including ‘exercise addiction’ , ‘exercise dependence’ , ‘obligatory exercising’, ‘exercise abuse’, and ‘compulsive exercise’. Among the most currently used (and psychometrically valid and reliable) instruments is the Exercise Addiction Inventory (EAI). The present study aimed to further explore the psychometric properties of the EAI by combining the datasets of a number of surveys carried out in five different countries (Denmark, Hungary, Spain, UK, and US) that have used the EAI with a total sample size of 6,031 participants. A series of multigroup confirmatory factor analyses (CFAs) were carried out examining configural invariance, metric invariance, and scalar invariance. The CFAs using the combined dataset supported the configural invariance and metric invariance but not scalar invariance. Therefore, EAI factor scores from five countries are not comparable because the use or interpretation of the scale was different in the five nations. However, the covariates of exercise addiction can be studied from a cross-cultural perspective because of the metric invariance of the scale. Gender differences among exercisers in the interpretation of the scale also emerged. The implications of the results are discussed, and it is concluded that the study’s findings will facilitate a more robust and reliable use of the EAI in future research

Observation of isotropic-dipolar to isotropic-Heisenberg crossover in Co-and Ni-substituted manganites

High-precision ac susceptibility data have been taken on the La0.7Pb0.3Mn1?y (Co, Ni)yO3 (y = 0, 0.1, 0.2 and 0.3) manganite system over a wide range of amplitudes and frequencies of the ac driving field in a temperature range that embraces the critical region near the ferromagnetic (FM)?paramagnetic (PM) phase transition (occurring at the Curie point TC). Elaborate data analysis was performed that (i) enabled the first observation of a crossover from a three-dimensional (3D; d = 3) isotropic long-range dipolar asymptotic critical behavior to a d = 3 isotropic short-range Heisenberg critical regime as the temperature is raised from TC in the compositions y 6= 0 (no such crossover is observed in the parent compound, y = 0) and (ii) brought out clearly the importance of dipole?dipole interactions between the eg electron spins and/or between eg?t2g electron spins in establishing long-range FM order in the insulating state. The final charge and spin states of Co and Ni ions, substituting for the Mn3+ and/or Mn4+ ions, are arrived at by using a scenario of substitution that is consistent not only with the present results but also with the previously published structural, thermo-gravimetric, bulk magnetization, dc magnetic susceptibility and electrical resistivity data on the same system. The marked similarity seen between the magnetic behavior of the manganite system in question and the quenched random-exchange ferromagnets, within and outside the critical region, suggests that the percolation model forms an adequate description of the FM metal-to-PM insulator transition

Size effects in the magnetic behaviour of TbAl_2 milled alloys

The study of the magnetic properties depending upon mechanical milling of the ferromagnetic polycrystalline TbAl_2 material is reported. The Rietveld analysis of the X-ray diffraction data reveals a decrease of the grain size down to 14 nm and -0.15 % of variation of the lattice parameter, after 300 hours of milling time. Irreversibility in the zero field cooled - field cooled (ZFC-FC) DC-susceptibility and clear peaks in the AC susceptibility between 5 and 300 K show that the long-range ferromagnetic structure is inhibited in favour of a disordered spin arrangement below 45 K. This glassy behaviour is also deduced from the variation of the irreversibility transition with the field (H^{2/3}) and frequency. The magnetization process of the bulk TbAl_2 is governed by domain wall thermal activation processes. By contrast, in the milled samples, cluster-glass properties arise as a result of cooperative interactions due to the substitutional disorder. The interactions are also influenced by the nanograin structure of the milled alloys, showing a variation of coercivity with the grain size, below the crossover between the multi- and single-domain behaviours.Comment: 23 pages, 11 figures, to appear in J. Phys.: Condens. Ma

Thermoremanence anomaly in Fe-Zr(B,Cu) Invar metallic glasses: Volume expansion induced ferromagnetism

We report the existence of a thermally induced sharp increase of thermoremanence around the Curie temperature of Invar-like Fe-Zr(B,Cu) soft magnetic glasses. Neutron-diffraction measurements indicate that a true enhancement of the average local magnetic moment, rather than only a change in the domain structure, occurs. Such enhancement has been tentatively attributed to the increasing volume expansion that takes place beyond the Curie temperature and reinforces ferromagnetism in some low-density clusters

Estrategias de competitividad turística en las áreas naturales protegidas de Quintana Roo, México

Las Áreas Naturales Protegidas (ANP) son espacios de protección de ecosistemas únicos o representativos de una región, que históricamente se han gestionado como fortalezas ecológicas, aunque también deberían vincularse con factores sociales y económicos, que en conjunto representan la clave del éxito de la conservación en el largo plazo, al integrar la triple base de la sustentabilidad por medio de estrategias culturalmente apropiadas para los sistemas y procesos ecológicos que impulsan la competitividad y permiten elevar la calidad de vida de las poblaciones que habitan al interior o área de influencia de estos espacios naturales. Sin embargo, la competitividad ha sido asociada al enfoque mercantilista, por lo que el aprovechamiento turístico sustentable dentro de las ANP es limitado. Desde esta perspectiva, el objetivo fue determinar las estrategias de competitividad turística aplicadas en las Áreas Naturales Protegidas de Quintana Roo, México. Se aplicó una metodología cualitativa de triangulación con entrevistas a los administradores, revisión de la bibliografía especializada y notas de campo. El modelo modificado de Kay fue la base teórica para recolectar datos de la administración de las ANP y los resultados se clasificaron según la propuesta de Porter sobre estrategias de competitividad. Entre los resultados se destaca que la mayoría de las ANP aplica la estrategia de Demarketing, C.O. Isla Mujeres y Tulum aplican la diferenciación y Sian Ka´an la segmentación, aunque todas apoyan la sustentabilidad ecológica y social, pero la económica prácticamente no se considera. El subsidio económico para favorecer el acceso, la ausencia de centros de educación ambiental, capacidades limitadas de los agentes locales y falta de coordinación y consenso entre instituciones federales, cooperativas locales y ejidos, son limitantes para mejorar la competitividad turística. Se concluye que en las ANP las estrategias de competitividad se aplican sin la lógica económica, por lo cual no se integran las bases de la sustentabilidad

Application of a behavioral objective evidence of evaluation of the influence of others in the performance in soccer

Se presenta el desarrollo de una prueba objetiva basada en el uso de un dinamómetro manual para analizar la influencia que ejerce la presencia de otras personas significativas, como el entrenador o los compañeros, en jugadores de fútbol infantil, cadete y juvenil de la Comunidad Autónoma de Madrid. Su aplicación permite superar las limitaciones presentadas por las pruebas de autoinforme tradicionales, analizando la validez convergente que tienen los resultados obtenidos con los encontrados en la escala de “Influencia de la evaluación del rendimiento” del cuestionario de características psicológicas relacionadas con el rendimiento deportivo factorizado CPRD-f (Olmedilla, García y Martínez, 2006). Los resultados obtenidos muestran la utilidad del empleo de una técnica objetiva como la planteada en el análisis de la influencia que tienen los otros en el rendimiento individualAn objective test, by using a hand dynamometer is presented in order to analyze the influence of significant people as the coach or the team mates in grip strength performance of young soccer players. Through this objective test was possible to overcome the methodological limitations presented by the traditional self-reported measures. The convergent validity between the dynamometer test results and the values obtained from the “Influence of performance evaluation scale” of the Psychological Characteristics related to Sport Performance factored Questionnaire CPRD-f (Olmedilla, García y Martínez, 2006) was also analyzed. The results showed the usefulness of an objective test as the hand dynamometer to analyze the influential role of significant people on individual performanceApresentamos o desenvolvimento de uma prova objetiva baseada no uso de um dinamômetro manual para analisar a influencia que exerce a presença de outras pessoas significativas, como o treinador ou os companheiros nos jogadores de futebol infantis, cadetes e juniores da Comunidad Autónoma de Madrid. Sua aplicação permite superar as limitações apresentadas pelas provas auto-informes tradicionais, analisando a validez convergente que tem os resultados obtidos com os encontrados na escala de “influencia da avaliação do rendimento” do questionário de características psicológicas relacionadas com o rendimento esportivo fatorizado CPRD-f (Olmedilla, García y Martínez, 2006). Os resultados obtido mostram a utilidade da aplicação técnica objetiva como a proposta na analises da influencia que tem os outros no rendimento individualEsta investigación ha sido parcialmente financiada gracias al proyecto de I+D+I MICINN PSI2011-2700