Particle fluxes and their drivers in the Avilés submarine canyon and adjacent slope, central Cantabrian margin, Bay of Biscay

Versión del edito

Similarity in the difference: changes in community functional features along natural and anthropogenic stress gradients.

The effect of stressors on biodiversity can vary in relation to the degree to which biological communities have adapted over evolutionary time. We compared the responses of functional features of stream insect communities along chronic stress gradients with contrasting time persistence. Water salinity and land use intensification were used as examples of natural (long-term persistent) and anthropogenic (short-term persistent) stressors, respectively. A new trait-based approach was applied to quantify functional diversity components and functional redundancy within the same multidimensional space, using metrics at the taxon and community levels. We found similar functional responses along natural and anthropogenic stress gradients. In both cases, the mean taxon functional richness and functional similarity between taxa increased with stress, whereas community functional richness and functional redundancy decreased. Despite the differences in evolutionary persistence, both chronic stressors act as strong nonrandom environmental filters, producing convergent functional responses. These results can improve our ability to predict functional effects of novel stressors at ecological and evolutionary scales

Seasonality and predictability shape temporal species diversity

Temporal environmental fluctuations, such as seasonality, exert strong controls on biodiversity. While the effects of seasonality are well known, the predictability of fluctuations across years may influence seasonality in ways that are less well understood. The ability of a habitat to support unique, non‐nested assemblages of species at different times of the year should depend on both seasonality (occurrence of events at specific periods of the year) and predictability (the reliability of event recurrence) of characteristic ecological conditions. Drawing on tools from wavelet analysis and information theory, we developed a framework for quantifying both seasonality and predictability of habitats, and applied this using global long‐term rainfall data. Our analysis predicted that temporal beta diversity should be maximized in highly predictable and highly seasonal climates, and that low degrees of seasonality, predictability, or both would lower diversity in characteristic ways. Using stream invertebrate communities as a case study, we demonstrated that temporal species diversity, as exhibited by community turnover, was determined by a balance between temporal environmental variability (seasonality) and the reliability of this variability (predictability). Communities in highly seasonal mediterranean environments exhibited strong oscillations in community structure, with turnover from one unique community type to another across seasons, whereas communities in aseasonal New Zealand environments fluctuated randomly. Understanding the influence of seasonal and other temporal scales of environmental oscillations on diversity is not complete without a clear understanding of their predictability, and our framework provides tools for examining these trends at a variety of temporal scales, seasonal and beyond. Given the uncertainty of future climates, seasonality and predictability are critical considerations for both basic science and management of ecosystems (e.g., dam operations, bioassessment) spanning gradients of climatic variability

Effect of the carbon nanotube surface characteristics on the conductivity and dielectric constant of carbon nanotube/poly(vinylidene fluoride) composites

Commercial multi-walled carbon nanotubes (CNT) were functionalized by oxidation with HNO3, to introduce oxygen-containing surface groups, and by thermal treatments at different temperatures for their selective removal. The obtained samples were characterized by adsorption of N2 at -196°C, temperature-programmed desorption and determination of pH at the point of zero charge. CNT/poly(vinylidene fluoride) composites were prepared using the above CNT samples, with different filler fractions up to 1 wt%. It was found that oxidation reduced composite conductivity for a given concentration, shifted the percolation threshold to higher concentrations, and had no significant effect in the dielectric response

Rural revival? The rise in internal migration to rural areas during the COVID-19 pandemic. Who moved and where?

During the outbreak of the COVID-19 pandemic, anecdotal evidence of a “rural revival” emerged mirroring the “urban exodus” hypothesis. Currently, we know that internal migration to rural areas increased in some countries during 2020, although not with the intensity speculated by the media. However, little is known about the attributes of rural areas attracting migrants and demographic composition of migration inflows. Drawing on administrative population register data, we analysed the main types of rural areas pulling internal migrants in Spain and their demographic characteristics, namely age, sex and place of birth. Our results show that in-migration increased in rural areas close to cities and with high prevalence of second homes. Inflows to rural areas comprised migrants across a wide age spectrum, from young adults and families to retired individuals. These flows also comprised foreign-born populations from high socio-economic background, particularly Latin Americans and individuals from high-income countries. Our findings suggest unequal impacts of the COVID-19 pandemic on the conterurbanisation process, triggering population movements among high-socioeconomic groups from cities to rural area

Un sistema de cuentas para la valoración de los efectos comerciales y ambientales del gasto público en la mitigación del fuego en el bosque mediterráneo

This paper proposes an economic accounting system for measuring the commercial and environmental effects of public spending in mitigation of forest fires in Mediterranean areas. It describes the application of this system (Agroforestry Accounts System) in the Alcornocales Natural Park. The habitat of this natural area is very important for the breeding and recovery of Mediterranean wildlife in danger of extinction or with conservation problems, and is considered by the public visitors and the private owners with a high environmental value. The level of public spending in the fight against forest fires of the Andalucía region (INFOCA) is quite significant in the Alcornocales Natural Park. The reduction of hectares of cork oaks trees destroyed by fire since the introduction of the INFOCA programme and the simultaneous increase in public funding provided for that purpose make it appropriate the design of an accounting tool to conduct an economic analysis of the contribution made by the INFOCA to the total social income generated in the Natural Park. The results make it possible to reach conclusions concerning the benefits of such public spending on society as a whole, which must be gained to offset the cost involved.Este artículo propone un sistema de cuentas económicas para la medición de los efectos comerciales y ambientales del gasto público dedicado a la mitigación de los incendios forestales en bosques mediterráneos. Se presenta una aplicación de este sistema (Sistema de Cuentas Agroforestales) en el Parque Natural de los Alcornocales. El hábitat de este espacio natural es de gran interés para la cría y recuperación de especies salvajes mediterráneas en peligro de extinción o con problemas de conservación, y está considerado por los visitantes públicos y los propietarios privados de un elevado valor ambiental. El gasto público en la lucha contra los incendios forestales de la Comunidad Autónoma de Andalucía (INFOCA) alcanza una cuantía notable en el Parque Natural de los Alcornocales. La reducción de hectáreas de alcornocal quemadas desde la implantación del INFOCA y el paralelo incremento de fondos públicos destinados a tal fin, hace aconsejable el desarrollo de una herramienta contable que facilite el análisis económico de la contribución del INFOCA a la renta total generada en el Parque. Los resultados permiten extraer conclusiones sobre los beneficios que este tipo de gasto público debieran generar a la sociedad para que alcanzara una rentabilidad económica adecuada

The effect of nanotube surface oxidation in the electrical response of MWCNT/PVDF nanocomposites

Carbon nanotubes / poly(vinylidene fluoride) composites were prepared using CNT with different oxidation and thermal treatments. The oxidation procedure leads to CNT with the most acidic characteristics that lower the degree of crystallinity of the polymer and contribute to a large increase of the dielectric constant. The surface treatments, in general, increase percolation threshold and decrease conductivity, but, on the other hand, are able to promote the nucleation of the electroactive phase of the polymer, which is suitable for the use of PVDF in sensors, actuators and other smart materials applications. Finally, the surface treatments do not seem to affect CNT interaction among them, reaching similar degrees of dispersion in all cases, as shown by the SEM results. The maximum value of the dielectric constant is ~630. It is demonstrated that the composite conductivity can be attributed to a hopping mechanism that is strongly affected by the surface treatment of the CNT.The authors thank the Fundacao para a Ciencia e a Tecnologia (FCT), Portugal, for financial support through the projects PTDC/CTM/69316/2006 and NANO/NMed-SD/0156/2007), and CIENCIA 2007 program for S.A.C.; V. S., J.S. and J.N.P. also thank FCT for the SFRH/BPD/63148/2009, SFRH/BD/60623/2009 and SFRH/BD/66930/2009 grants

Influencia del pick and roll en el juego de ataque en baloncesto de alto nivel

El objetivo de este estudio fue caracterizar las acciones del pickand roll y su influencia en el juego en baloncesto de alto nivel. Se analizóla eficacia táctica y de marcador en función de distintos factores queinciden en las situaciones de juego mediante un diseño observacional nomotético,puntual y multidimensional en 18 equipos de la liga ACB debaloncesto. Un instrumento observacional ad hoc (VTP&R) fue validadopor un panel de 20 expertos de alto nivel y se comprobó la fiabilidad en laobservación por parte de los investigadores. El análisis de datos se realizómediante el análisis secuencial de retardos, el análisis de coordenadaspolares y los estadísticos descriptivos cuantitativos. Del total de accionesanalizadas (n=3895), el 25,3% se corresponden a pick and roll (n=984). Soloel 36,3% de las acciones de pick and roll se han mostrado eficaces en elmarcador, mientras que el 85,7% lo son tácticamente. La interpretaciónde los resultados muestra el interés en complementar el análisis del juegoen baloncesto a través de los mixed methods. La posibilidad de determinarqué acciones se realizan en cada momento del partido y de qué manera seejecutan, así como establecer patrones de respuesta táctica en función delos distintos factores que intervienen en el juego, justifica la utilidad de losresultados aquí obtenidos y se concluye el interés en incorporar las distintastécnicas analíticas de la metodología observacional a los procesos de análisisdel baloncesto