Attenuation lengths of high energy photoelectrons in compact and mesoporous SiO2 films

El pdf del artículo es la versión post-print.We have experimentally evaluated attenuation lengths (AL) of photoelectrons traveling in compact and micro and mesoporous (∼ 45% voids) SiO 2 thin films with high (8.2-13.2 keV) kinetic energies. The films were grown on polished Si(100) wafers. ALs were deduced from the intensity ratio of the Si 1s signal from the SiO 2 film and Si substrate using the two-peaks overlayer method. We obtain ALs of 15-22 nm and 23-32 nm for the compact and porous SiO 2 films for the range of kinetic energies considered. The observed AL values follow a power law dependence on the kinetic energy of the electrons where the exponent takes the values 0.81 ± 0.13 and 0.72 ± 0.12 for compact and porous materials, respectively. © 2012 Elsevier B.V. All rights reserved.We thank the Spanish MICINN (projects MAT2010-18447 and Consolider CSD2008-00023 and CPAN CSD2007-42) for financial support.Peer Reviewe

Role of the metal supply pathway on silicon patterning by oblique ion beam sputtering

The dynamics of the pattern induced on a silicon surface by oblique incidence of a 40 keV Fe ion beam is studied. The results are compared with those obtained for two reference systems, namely a noble gas ion beam either without or with Fe co-deposition. The techniques employed include Atomic Force Microscopy, Rutherford Backscattering Spectrometry, Transmission Electron Microscopy, X-ray Photoelectron and hard X-ray photoelectron spectroscopies, as well as Superconducting Quantum Interference Device measurements. The Fe-induced pattern differs from those of both reference systems since a pattern displaying short hexagonal ordering develops, although it shares some features with them. In both Fe systems a chemical pattern, with iron silicide-rich and -poor regions, is formed upon prolonged irradiation. The metal pathway has a marked influence on the patterns’ morphological properties and on the spatial correlation between the chemical and morphological patterns. It also determines the iron silicide stoichiometry and the surface pattern magnetic properties that are better for the Fe-implanted system. These results show that in ion-beam-induced silicon surface patterning with reactive metals, the metal supply pathway is critical to determine not only the morphological pattern properties, but also the chemical and magnetic one

Dipturus trachydermus, Roughskin Skate

The Roughskin Skate (Dipturus trachydermus) is a large skate (to 265 cm total length) that occurs in the Southeast Pacific and Southwest Atlantic from Coquimbo, Chile (31°S), south around Cape Horn and north to Río de la Plata, Uruguay, including the Falkland Islands (Malvinas). It is demersal on the outer continental shelf and upper slope at depths of 85–480 m, but is most commonly found at 200–350 m in Chile and shallower (80–150 m) in Argentina. It is captured in industrial trawl fisheries for hake (Merluccius spp.), and artisanal bottom longline fisheries that encompass nearly the entire geographic and depth range of this species in Chile and Argentina. In Chile, it was a secondary catch of the target skate fishery which ramped up in 1993 as a direct result of the arrival of Korean skate traders who provided a market that incentivised fishers to target and retain this species for international trade.Fil: Dulvy, N. K.. University Fraser Simon; CanadáFil: Acuña, E.. Universidad Católica del Norte; ChileFil: Bustamante, C.. Universidad de Antofagasta; ChileFil: Chiaramonte, Gustavo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia". Estación Hidrobiológica de Puerto Quequén (sede Quequén); ArgentinaFil: Concha, F.. Universidad de Valparaíso; ChileFil: Cuevas, J. M.. Wildlife Conservation Society; Estados UnidosFil: Herman, K.. Georgia Aquarium; Estados UnidosFil: Paesch, L.. Dirección Nacional de Recursos Acuáticos; UruguayFil: Pompert, J.. No especifíca;Fil: Rincon, G.. Universidade Federal Do Maranhao.; BrasilFil: Velez Zuazo, X.. Smithsonian Conservation Biology Institute; Estados Unido

Bathyraja albomaculata, Whitedotted Skate

The Whitedotted Skate (Bathryraja albomaculata) is a large (to 150 cm total length) skate that occurs in the Southeast Pacific and Southwest Atlantic Oceans from Coquimbo, Chile south around Cape Horn and north to Uruguay, including the Falkland Islands (Malvinas) and the Burdwood Bank, and is demersal on the inshore continental shelf and upper slope at depths of 55?945 m. It is captured in industrial longline and trawl fisheries, which operate throughout its range. Although discarded dead in some parts of its range, it is utilized for human consumption in others. In the Southeast Pacific, skates targeted in fisheries (Dipturus spp.) have undergone severe population reductions where this species is captured as unmanaged bycatch. In the Southwest Atlantic, there are some general management measures in place for skates but they are not species-specific. This skate is now absent from approximately one-third of its distribution in Argentina due to heavy fishing pressure on skates. Overall, due to the level of exposure to inadequately managed fisheries, noted population reductions in other skates, its lack of refuge at depth, a suspected decline in area of occupancy, and a combination of declines in some areas and stability in others, it is suspected that the Whitedotted Skate has undergone a population reduction of 30-49% over the past three generations (40.5 years). Therefore, the Whitedotted Skate is assessed as Vulnerable A2bd.Fil: Pollom, R.. University Fraser Simon; CanadáFil: Dulvy, N. K.. University Fraser Simon; CanadáFil: Acuña, E.. Universidad Católica del Norte; ChileFil: Bustamante, C.. Universidad de Antofagasta; ChileFil: Cevallos, A.. No especifíca;Fil: Chiaramonte, Gustavo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia". Estación Hidrobiológica de Puerto Quequén (sede Quequén); ArgentinaFil: Cuevas, J. M.. Wildlife Conservation Society; Estados UnidosFil: Herman, K.. Georgia Aquarium; Estados UnidosFil: Navia, A. F.. No especifíca;Fil: Paesch, L.. Dirección Nacional de Recursos Acuáticos; UruguayFil: Pompert, J.. No especifíca;Fil: Velez Zuazo, X.. Smithsonian Conservation Biology Institute; Estados Unido

Conservation Agriculture as a Sustainable System for Soil Health: A Review

Soil health is a term used to describe the general state or quality of soil, and in an agroecosystem, soil health can be defined as the ability of the soil to respond to agricultural practices in a way that sustainably supports both agricultural production and the provision of other ecosystem services. Conventional agricultural practices cause deterioration in soil quality, increasing its compaction, water erosion, and salinization and decreasing soil organic matter, nutrient content, and soil biodiversity, which negatively influences the productivity and long-term sustainability of the soil. Currently, there are many evidences throughout the world that demonstrate the capability of conservation agriculture (CA) as a sustainable system to overcome these adverse effects on soil health, to avoid soil degradation and to ensure food security. CA has multiple beneficial effects on the physical, chemical, and biological properties of soil. In addition, CA can reduce the negative impacts of conventional agricultural practices on soil health while conserving the production and provision of soil ecosystem services. Today, agricultural development is facing unprecedented challenges, and CA plays a significant role in the sustainability of intensive agriculture. This review will discuss the impact of conservation agricultural practices on soil health and their role in agricultural sustainability

EUSEDcollab: a network of data from European catchments to monitor net soil erosion by water

As a network of researchers we release an open-access database (EUSEDcollab) of water discharge and suspended sediment yield time series records collected in small to medium sized catchments in Europe. EUSEDcollab is compiled to overcome the scarcity of open-access data at relevant spatial scales for studies on runoff, soil loss by water erosion and sediment delivery. Multi-source measurement data from numerous researchers and institutions were harmonised into a common time series and metadata structure. Data reuse is facilitated through accompanying metadata descriptors providing background technical information for each monitoring station setup. Across ten European countries, EUSEDcollab covers over 1600 catchment years of data from 245 catchments at event (11 catchments), daily (22 catchments) and monthly (212 catchments) temporal resolution, and is unique in its focus on small to medium catchment drainage areas (median = 43 km(2), min = 0.04 km(2), max = 817 km(2)) with applicability for soil erosion research. We release this database with the aim of uniting people, knowledge and data through the European Union Soil Observatory (EUSO)

The 'indigenous native peasant' trinity: imagining a plurinational community in Evo Morales's Bolivia

Over the last two decades Latin America has been a laboratory for the implementation of new models of state and citizenship. In Bolivia the (neo)liberal multicultural paradigm dominant in the 1990s has recently been replaced by a plurinational paradigm, which implies a deepening of the decentralization process and the strengthening of rights for traditionally marginalized social sectors. This paper describes the process of construction of a plurinational ‘imagined community’ and, in particular, of one of its core narratives: The ‘indigenous native peasant’. I argue that the negotiation of this collective identity and its inclusion as one of the core ideas in the new constitution is the result of a contingent strategy in response to a highly conflictive scenario, which has not been, however, able to trigger a change in the way people identify themselves. Yet in recent years, social movements’ identities have been shaped by centrifugal forces. These forces should be understood as the result of a process of collective actors’ adaptation to institutional and regulatory reforms and contribute to explaining the increase of new intrasocietal conflicts linked to the redefinition of citizenship and territorial boundaries

How land use/land cover changes can affect water, flooding and sedimentation in a tropical watershed: a case study using distributed modeling in the Upper Citarum watershed, Indonesia

[EN] Human activity has produced severe LULC changes within the Upper Citarum watershed and these changes are predicted to continue in the future. With an increase in population parallel to a 141% increment in urban areas, a reduction of rice fields and the replacement of forests with cultivations have been found in the past. Accordingly, LCM model was used to forecast the LULC in 2029. A distributed model called TETIS was implemented in the Upper Citarum watershed to assess the impact of the different historical and future LULC scenarios on its water and sediment cycles. This model was calibrated and validated with different LULCs. For the implementation of the sediment sub-model, it was crucial to use the bathymetric information of the reservoir located at the catchment's outlet. Deforestation and urbanization have been shown to be the most influential factors affecting the alteration of the hydrological and sedimentological processes in the Upper Citarum watershed. The change of LULC decreases evapotranspiration and as a direct consequence, the water yield increased by 15% and 40% during the periods 1994-2014 and 2014-2029, respectively. These increments are caused by the rise of three components in the runoff: overland flow, interflow and base flow. Apart from that, these changes in LULC increased the area of non-tolerable erosion from 412 km(2) in 1994 to 499 km(2) in 2029. The mean sediment yield increased from 3.1 Mton -yr(-1) in the 1994 LULC scenario to 6.7 Mton-yr(-1) in the 2029 LULC scenario. An increment of this magnitude will be catastrophic for the operation of the Saguling Dam.This study was partially funded by the Spanish Ministry of Economy and Competitiveness through the research projects TETISMED (CGL2014-58,127-C3-3-R) and TETISCHANGE (RTI2018-093717-B-I00). The authors are also thankful to the Directorate General of Higher Education of Indonesia (DIKTI) for the Ph.D. funding of the first author.Siswanto, SY.; Francés, F. (2019). How land use/land cover changes can affect water, flooding and sedimentation in a tropical watershed: a case study using distributed modeling in the Upper Citarum watershed, Indonesia. Environmental Earth Sciences. 78(17):1-15. https://doi.org/10.1007/s12665-019-8561-0S115781

Multiple Distant Origins for Green Sea Turtles Aggregating off Gorgona Island in the Colombian Eastern Pacific

Mitochondrial DNA analyses have been useful for resolving maternal lineages and migratory behavior to foraging grounds (FG) in sea turtles. However, little is known about source rookeries and haplotype composition of foraging green turtle aggregations in the southeastern Pacific. We used mitochondrial DNA control region sequences to identify the haplotype composition of 55 green turtles, Chelonia mydas, captured in foraging grounds of Gorgona National Park in the Colombian Pacific. Amplified fragments of the control region (457 bp) revealed the presence of seven haplotypes, with haplotype (h) and nucleotide (π) diversities of h = 0.300±0.080 and π = 0.009±0.005 respectively. The most common haplotype was CMP4 observed in 83% of individuals, followed by CMP22 (5%). The genetic composition of the Gorgona foraging population primarily comprised haplotypes that have been found at eastern Pacific rookeries including Mexico and the Galapagos, as well as haplotypes of unknown stock origin that likely originated from more distant western Pacific rookeries. Mixed stock analysis suggests that the Gorgona FG population is comprised mostly of animals from the Galapagos rookery (80%). Lagrangian drifter data showed that movement of turtles along the eastern Pacific coast and eastward from distant western and central Pacific sites was possible through passive drift. Our results highlight the importance of this protected area for conservation management of green turtles recruited from distant sites along the eastern Pacific Ocean