439 research outputs found
Assessing vulnerability of reptile hotspots through temporal trends of global change factors in the Iberian Peninsula
Producción CientíficaHabitat degradation and climate change are major threats to the long-term persistence of reptile populations. However, their roles on primary productivity instability remain unclear at certain scales. Besides, the design of protected areas has often overlooked reptiles or assumed that their ecological requirements are represented under the umbrella of more charismatic species. Here, we assess the vulnerability of areas of high diversity of reptiles in the Iberian Peninsula to global change using data from satellite imagery. We focused on primary productivity, climate and land-use change because they are indicators of environmental variability that might impair ecosystem functioning and alter wildlife communities. We used linear regressions to detect monotonic temporal trends in primary productivity (through the enhanced vegetation index, EVI) and climate (mean temperature and accumulated precipitation) at two spatial resolutions (10-km2 UTM squares and CORINE land-cover polygon level) over the period 2000–2020. We also determine how the strength of land-use and climate change affected the intensity of change in primary productivity at both spatial scales with multivariate linear regressions. We identified 339 hotspots (10-km2 UTM squares) and monotonic increments of temperature, EVI or both occurred in 43 %, 16 % and 22 % of them, respectively. Positive trends of the EVI were related to increasing temperatures and changes in shrubland and forest cover. Within the hotspots with monotonic increments in EVI and temperature, EVI increments occurred in 60 % of the CORINE polygons that did not change their land-cover type, with stronger increases in tree crops. Finally, the Natura 2000 network provides only moderate protection to reptile hotspots, being most of the vegetation types relatively underrepresented. The proportion of forest and shrubland protected by the Natura 2000 network was higher in hotspots where EVI changed. Our procedures are relevant to prioritize hotspots requiring ground monitoring that allows economic and time savings.Ministerio para la Transición Ecológica y el Reto Demográfico (Fundación Biodiversidad)(project PR2006_20/01, REPROCLIM to PA)Junta de Castilla y León and co-financed by the European Union (Revista Pre prueba 30 "PR2006_20/01 REPROCLIM‟) and (proyect CLU-2019-01
The improvements of power management for clustered type large scope wireless sensor networks2010
Fuente Aragón, PDL. (2010). The improvements of power management for clustered type large scope wireless sensor networks2010. http://hdl.handle.net/10251/10244.Archivo delegad
Effects of temporal bias on the assessment of an ecological perturbation: a case study of the Prestige oil spill
The impacts of unpredictable ecological perturbations are often assessed via measurements of environmental change only after the event has occurred. Temporal series of satellite images provide a cost-effective way to gather information before ecological perturbations occur. However, in previous studies, the disturbances have neither been always centred in time in the series of the focal environmental variable nor has the relevance of the temporal coverage been explicitly tested through factorial designs. In this study, we manipulated the temporal coverage and the position of the disturbance event in the temporal series to examine whether and how the assessment is affected. Specifically, we tested the effect of the Prestige oil spill on monthly sea chlorophyll concentration and net primary productivity along the north-western Spanish coast. We designed planned comparisons through factorial analyses to test two alternative hypotheses: (1) the spill has negative consequences on phytoplankton activity and/or abundance due to physiological constraints or (2) it has positive consequences on phytoplankton abundance as a result of changes in biotic interactions. The relevance of the statistical effects was critically dependent on the temporal coverage and the position of the spill event in the temporal series. Short periods (three years) were insufficient to cover the range of variability even if the disturbance was centred in the time series. Similarly, results from longer time series (up to eight years) in which the event was temporally biased (at the beginning of the time series) also differed from those that were centred in the entire time window. Temporal series for the study of ecological impacts should be as long as necessary to encompass the temporal variability of the study systems (up to nine years in our study case), and the disturbance event should be centred in the time series to reduce potential spurious effects of temporal autocorrelation. However, our results revealed that each one of these requirements alone was not sufficient to encompass all of the natural variability, and thus both requirements should be met. For impact assessments we encourage the use of unbiased satellite data series to complement in situ measurements.PA was supported by a 'Ramón y Cajal' contract (RYC-2011-07670) and by the project CGL2014-56416-P, and DS-F by a 'Juan de la Cierva' contract (JCI-2011-10529), all from the Spanish Ministry of Economy and Competitiveness. SV was supported by a postdoctoral contract from the Universidad de Alcalá.Peer reviewe
Thomas Arnold en la obra de Coubertin. El mito de Arnold
The aim of this essay is to analyse the writings by Coubertin that cover nearly fifty years of his tireless and prolific handwritten activity. In those pieces of writing the Baron expresses his fascination with Arnold as an educator and a reformer. Coubertin states that Arnold’s pedagogy held sport as the central mechanism, placing Arnold in a privileged position in the physical revival of England. However, Arnold was very little (or not at all) interested in sports. The methodology of this study is historical, based on primary and secondary sources. As a conclusion, Arnold and his reforming actions in Rugby were so important for Coubertin that he defined the Headmaster of Rugby public school as the best educator of modern time, responsible for the spiritual and political recovery which took place in England during the second half of the 19th century.El objetivo de este trabajo es analizar escritos de Coubertin, que abarcan casi cincuenta años de su infatigable y prolífica actividad manuscrita, en los que el barón expresa su fascinación por Arnold en sus facetas de pedagogo y reformador. Coubertin sostiene que la pedagogía arnoldiana tenía el deporte como engranaje central, ocupando Arnold un lugar privilegiado en el renacimiento físico de Inglaterra. Sin embargo, Arnold estaba muy poco (o nada) interesado por los deportes. La metodología de este estudio es histórica y se fundamenta en fuentes primarias y secundarias. Como conclusión, para Coubertin fue tan importante Arnold y su acción reformadora en Rugby, que lo definió como el mejor pedagogo de los tiempos modernos y le atribuyó la recuperación espiritual y política que tuvo lugar en Inglaterra desde mediados del siglo XIX
Cardiac Evaluation of Exercise Testing in a Contemporary Population of Preschool Children: A New Approach Providing Reference Values
The objective of this study was to evaluate cardiac autonomic function at rest, during maximal exercise, and in post-exercise recovery, to determine sex-specific and age-specific differences in resting heart rate (RHR), linear and spectral parameters of Heart Rate Variability (HRV), HRpeak, and heart rate recovery (HRR) after one and five minutes, in preschool children. This study involved a cohort of 167 healthy children (79 girls) aged 3 to 6 years that were selected from several schools in southern Spain. A 10 x 20 m test was conducted, and the cardiovascular response was recorded. No significant differences were found in all variables between the sexes. However, a significant reduction in RHR and an increase in HRR were found from age 4 to age 6. HRV parameters at rest were higher in older children. No associations between 10 x 20 m performance, weight status, and cardiac parameters were found. Simple linear regression analysis revealed that heart rate reserve (HRr), HRR5min, RMSSD, and HF were the variables that showed association with all HR parameters. There was also a significant correlation between HRr and HRR5min. In conclusion, cardiovascular autonomic function during rest, exercise, and recovery in Spanish preschool children was not influenced by sex, although older children showed greater cardiovascular modulation. Cardiorespiratory fitness status was not associated with HR response
The Icy Road towards the First Olympic Winter Games in Chamonix 1924
The International Olympic Committee (IOC) faced many obstacles in deciding to initiate the first Olympic Winter Games and subse- quently organize in Chamonix, in 1924 the "Winter Sports Week", now considered the first winter Olympics. Pierre de Coubertin's own thoughts about winter sports evolved only slowly, which together with his friendship with Viktor Balck, constituted the main obstacle for the winter Olympics. The success of the Nordic Games, the powerful Swedish nationalistic winter sports festival run by Balck, at the beginning of the twentieth century influenced Coubertin's view that an additional winter Olympic competition was unnecessary. Prior limited inclusion of winter sports, such as figure skating, in the summer Olympic programme made the status of some events unclear. Influential members of the IOC disagreed about their possible place in the programme with Balck leading the opposition to include winter sports. Ultimately the French IOC members' advocacy for winter games in 1921, combined with Balck's retirement from the IOC as a result of his age, was instru- mental in the decision to allow Chamonix to host the first winter festival
Mecanismos para reducir los costes derivados de los encuentros agresivos en los machos de la lagartija serrana (Lacerta monticola).
Peer reviewe
Mecanismos para reducir los costes derivados de los encuentros agresivos en los machos de la lagartija serrana (Lacerta monticola).
Peer reviewe
Mecanismos para reducir los costes derivados de los encuentros agresivos en los machos de la lagartija serrana ("Lacerta monticola")
La presente tesis estudia los mecanismos que intervienen reduciendo los costes que suponen los encuentros agresivos entre los machos de L. Monticola, teniendo en cuenta factores como el de intruso-residente, familiaridad, habilidad competitiva y estacionalidad. Los machos de L.monticola son capaces detectar y discriminar sus propias secreciones femorales de las de otros machos a partir señales quimicas exclusivamente. Este hecho indica la utilización de las secreciones femorales en la comunicación intraespecifica. El uso del espacio y la exploración quimica de los machos de L.monticola en presencia de señales quimicas procedentes de otros machos conespecificos depende del tamaño relativo. Esto sugiere que son capaces de estimar la habilidad competitiva en relación con otros machos conespecíficos y en ausencia del emisor. Los machos de L.monticola son capaces de discriminar entre machos con especificos familiares y no familiares utilizando unicamente informacion quimica procedente de las secreciones femorales o los excrementos. El hecho de que los machos verdes sean de mayor tamaño, tengan mayor probabilidad de éxito en los ecuestres agonísticos, tengan areas más exclusivas frente a otros machos y un mayor grado de solapamiento con las hembras sugiere que la coloración verde podría actuar como señalizador de la habilidad competitiva. Los machos verdes presentan un solapamiento temporal mayor con otros machos que los machos marrones. A diferencia de los machos marrones, los machos verdes concentran el acceso a los recursos por la mañana lo que les podría permitir reducir los costes que implican las actividades conspicuas. Por otro lado, los machos marrones podrían tener que dispersar el acceso a los recursos de una forma oportunista. Las interacciones agonísticas, los niveles de actividad, el tamaño del area de campeo y el número de vecinos del mismo sexo decrecieron según se iba aproximando el periodo no reproductor en los machos pro no en las hembras. Estos resultados sugieren que el balance entre los costes y los beneficios es diferente en el periodo reproductor y no reproductor en los machos pero no en las hembras. El cambio gradual que se aprecie en los machos podría ser un mecanismo para reducir la frecuencia de las interacciones agonísticas
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