X-ray magnetic circular dichroism using x-ray phase retarders in the hard x-ray region

En este libro se estudia el magnetismo de la banda de conducción y de átomos no magnéticos en sistemas intermetálicos tierra-rara – metal de transición, mediante la técnica de dicroísmo magnético circular de rayos-X (XMCD) en la región de los rayos-X duros. Adicionalmente, se detalla el diseño y montaje experimental de una lámina retardadora de fase para la realización de medidas XMCD en la línea BM25-A del European Synchrotron Radiation Facility (ESRF) dedicada a espectroscopia de absorción de rayos-X (XAS)

Canonical and unconventional purposes and mechanisms

Selective autophagic degradation of cellular components underlies many of the important physiological and pathological implications that autophagy has for mammalian cells. Cytoplasmic vesicles, just like other intracellular items, can be subjected to conventional autophagic events where double-membrane autophagosomes specifically isolate and deliver them for lysosomal destruction. However, intracellular membranes appear to constitute common platforms for unconventional versions of the autophagic pathway, a notion that has become apparent during the past few years. For instance, in many cases of autophagy directed against bacterial phagosomes, subversion of the process results in multimembrane vacuoles that promote bacterial replication instead of the usual degradative outcome. In a different atypical modality, single-membrane vesicles can be labeled with LC3 to direct their contents for lysosomal degradation. In fact, single-membrane compartments of various kinds often provide an assembly site for the autophagic machinery to perform unanticipated nondegradative activities that range from localized secretion of lysosomal contents to melanosome function. Interestingly, many of these unconventional processes seem to be initiated through engagement of relevant nodes of the autophagic signaling network that, once activated, promote LC3 decoration of the targeted membrane, and some cases of inducer/receptor proteins that specifically engage those important signaling hubs have recently been described. Here we review the available examples of all autophagic variants involving membranous compartments, with a main focus on the more recently discovered unconventional phenomena where the usual degradation purpose of autophagy or its canonical mechanistic features are not completely conserved.Funding was provided by grants from the Ministerio de Ciencia e Innovación of the Spanish Government (Refs. SAF2008-00350 and SAF2011-23714), the Fundación Solórzano, the Junta de Castilla y León local government (Consejería de Educación, Ref. CSI001A10-2, and Consejería de Sanidad) and the Consejo Superior de Investigaciones Científicas (CSIC; Ref. 200720I026). Additional funding comes from the FEDER program of the European Union. EB is a graduate student funded by a predoctoral fellowship from the FPU program (Ministerio de Educación, MEC, Spanish Government).Peer Reviewe

Anàlisi del sistema agroecològic de Vila-seca : proposta de guia per a la descoberta del medi

S'ha elaborat una anàlisi del sistema agroecològic del municipi de Vila-seca (Tarragonès) per tal de realitzar en segon lloc, una proposta de guia per a la descoberta del medi per a infants d'entre 8 i 10 anys. A partir del treball de camp realitzat a la zona d'estudi s'han inventariat diferents elements del patrimoni socioecològic que es consideren de rellevada importància al terme. Entre ells destaquen oliveres, garrofers, avellaners, arbres singulars, masos, basses, marges de pedra seca i trones, els quals s'integren en el medi formant un veritable sistema agroecològic, fruit de la interacció entre vectors biofísics i socioeconòmics. D'altra banda, per tal de donar a conèixer aquest sistema s'ha realitzat una proposta de descoberta del medi agrícola a partir d'un itinerari d'educació ambiental per la zona estudiada, on s'engloben tots aquells elements d'especial interès en un recorregut de 2,9 quilòmetres. La guia disposa a més d'una sèrie d'activitats a realitzar a l'entorn per tal de motivar el sentiment de descoberta d'aquest sistema. D'aquesta manera, considerant les fortes pressions que aquest territori pateix per part de les infraestructures i les urbanitzacions és destriable la necessitat de conservació i l'addició dels elements inventariats al catàleg del Patrimoni del municipi.Se ha elaborado un análisis del sistema agroecológico del municipio de Vila-seca (Tarragonés) para realizar en segundo lugar, una propuesta de guía de descubrimiento del medio para escolares de entre 8 y 10 años. A partir del trabajo de campo realizado en la zona de estudio se han inventariado diferentes elementos del patrimonio socioecológico que se consideran de relevada importancia en el territorio. Entre ellos destacan olivos, algarrobos, avellanos, árboles singulares, masías, balsas, márgenes de piedra seca i tronas, los cuales se integran en el medio formando un verdadero sistema agroecológico, fruto de la interacción entre vectores biofísicos y socioeconómicos. Por otra parte, para dar a conocer este sistema se ha realizado una propuesta de descubrimiento del medio agrícola a partir de un itinerario de educación ambiental por la zona estudiada, donde se engloban todos aquellos elementos de especial interés en un recorrido de 2,9 kilómetros. La guía dispone además de una serie de actividades a realizar en el entorno con el fin de motivar el sentimiento de descubrimiento de este sistema. De esta manera, considerando las fuertes presiones que este territorio sufre por parte de las infraestructuras y las urbanizaciones es destacable la necesidad de conservación y la adición de los elementos inventariados en el catálogo del Patrimonio del municipio.It has been made an analysis of agro-ecological system of Vila-seca's town (Tarragonés) with the proposal of make an environmental education guide for schoolchildren between 8 and 10 years. From fieldwork in the study area it has been inventoried different socio-environmental heritage items that are considered of high importance in the territory. These include olive, carob, hazelnut, unique trees, farms, ponds, dry stone margins and "trones", which are integrated forming a true agro-ecological system, the result of the interaction between biophysical and socio-economic factors. Moreover, to raise awareness of this system it has been made an environmental education guide with a itinerary through the study area that encompasses all the elements of particular interest in a route of 2.9 kilometres. The guide also features a series of activities to do in the environment to encourage a sense of discovery of this system. Thus, considering the strong pressures that this area suffers from infrastructure and buildings is necessary to conserve and add the inventoried items in the Heritage's catalogue of the town

The richness of small pockets:Decapod species peak in small seagrass patches where fish predators are absent

Este artículo contiene 6 páginas, 3 figuras, 3 tablas.Patchy landscapes behave differently from continuous ones. Patch size can influence species behaviour, movement, feeding and predation rates, with flow-on consequences for the diversity of species that inhabit these patches. To understand the importance of patchiness on regional species pools, we measured decapod richness and abundance in several seagrass patches with contrasting sizes. Additionally, we evaluated potential drivers of patch-specific species distribution including resource abundance, predator habitat use and the structural complexity of patches. Our results showed a non-random distribution of decapod species: small patches were clear hotspots of diversity and abundance, particularly of larger-bodied epifaunal decapods. Interestingly, these hotspots were characterized by lower nutrient resources, lower canopy height, but also lower predator use. Small fish invertivores such as Coris julis and several species of Symphodus were mostly restricted to large patches. These resident predators may be critical in clumping predation in large patches with consequences for how biodiversity of their prey is distributed across the seascape. Our results highlight the idea that a habitat mosaic with both large and small seagrass patches would potentially bolster biodiversity because preys and predators may seek refuge in patches of different sizes.This research was funded by the Spanish Ministry of Science and Innovation (CTM2017-86695-C3-3-R) and supported J. B. (scholarship BES-2011-043630).Peer reviewe

TMEM59 defines a novel ATG16L1-binding motif that promotes local activation of LC3

Selective autophagy underlies many of the important physiological roles that autophagy plays in multicellular organisms, but the mechanisms involved in cargo selection are poorly understood. Here we describe a molecular mechanism that can target conventional endosomes for autophagic degradation. We show that the human transmembrane protein TMEM59 contains a minimal 19-amino-acid peptide in its intracellular domain that promotes LC3 labelling and lysosomal targeting of its own endosomal compartment. Interestingly, this peptide defines a novel protein motif that mediates interaction with the WD-repeat domain of ATG16L1, thus providing a mechanistic basis for the activity. The motif is represented with the same ATG16L1-binding ability in other molecules, suggesting a more general relevance. We propose that this motif may play an important role in targeting specific membranous compartments for autophagic degradation, and therefore it may facilitate the search for adaptor proteins that promote selective autophagy by engaging ATG16L1. Endogenous TMEM59 interacts with ATG16L1 and mediates autophagy in response to Staphylococcus aureus infection.This work was funded by grants from the Ministerio de Ciencia e Innovación of the Spanish Government (Refs SAF2008‐00350 and SAF2011‐23714), Fundación Solórzano, Junta de Castilla y León (Consejería de Educación, Ref. CSI001A10‐2, and Consejería de Sanidad) and Consejo Superior de Investigaciones Científicas (CSIC; Ref. 200720I026). Additional funding comes from the FEDER programme of the European Union. EB is a graduate student funded by a predoctoral fellowship from the FPU programme (Ministerio de Educación, MEC, Spanish Government). ML is funded by JAE‐Doc and Juan de la Cierva postdoctoral contracts (MEC and Social European Fund of the European Union, 2007–2013). AF is funded by a long‐term EMBO postdoctoral fellowship and a Juan de la Cierva contract. KP is a graduate student funded by an FPI fellowship (MEC).Peer Reviewe

Evaluating potential artifacts of tethering techniques to estimate predation on sea urchins

Measuring the strength of trophic interactions in marine systems has been central to our understanding of community structuring. Sea urchin tethering has been the method of choice to evaluate rates of predation in marine benthic ecosystems. As standardly practiced, this method involves piercing the urchin test, potentially introducing significant methodological artifacts that may influence survival or detection by predators. Here we assess possible artifacts of tethering comparing invasive (pierced) and non-invasive tethering techniques using the sea urchin Paracentrotus lividus. Specifically we looked at how degree of confinement and high water temperature (first order artifacts), and predator guild and size of the prey (second order artifacts) affect the survival and/or detectability of pierced urchins. Our results show that first order artifacts only arise when pierced sea urchins are placed in sheltered bays with confined waters, especially when water temperature reaches extremely high levels. Prey detectability did not increase in pierced sea urchins for the most common predators. Also, test piercing did not alter the preferences of predators for given prey sizes. We conclude that the standard tethering technique is a robust method to test relative rates of sea urchin predation. However, local conditions could increase mortality of the tethered urchin in sheltered bays or in very high temperature regimes. Under these conditions adequate pierced controls (within predator exclusions) need to be included in assays to evaluate artifactual sources of mortality

Immanent conditions determine imminent collapses: nutrient regimes define the resilience of macroalgal communities

Este artículo contiene 9 páginas, 5 figuras.Predicting where state-changing thresholds lie can be inherently complex in ecosystems characterized by nonlinear dynamics. Unpacking the mechanisms underlying these transitions can help considerably reduce this unpredictability. We used empirical observations, field and laboratory experiments, and mathematical models to examine how differences in nutrient regimes mediate the capacity of macrophyte communities to sustain sea urchin grazing. In relatively nutrient-rich conditions, macrophyte systems were more resilient to grazing, shifting to barrens beyond 1 800 g m22 (urchin biomass), more than twice the threshold of nutrient-poor conditions. The mechanisms driving these differences are linked to how nutrients mediate urchin foraging and algal growth: controlled experiments showed that low-nutrient regimes trigger compensatory feeding and reduce plant growth, mechanisms supported by our consumer–resource model. These mechanisms act together to halve macrophyte community resilience. Our study demonstrates that by mediating the underlying drivers, inherent conditions can strongly influence the buffer capacity of nonlinear systems.The Spanish Ministry of Science and Innovation funded this research (projects CMT2010-22273-C02-01-02 and CMT2013- 48027-C03-R) and supported J.B. (scholarship BES-2011-043630) and D.A. (Ramon y Cajal fellowship). The Spanish National Research Council supported R.A.’s visitorship (CSIC-201330E062).Peer reviewe

Herbivore control in connected seascapes: habitat determines when population regulation occurs in the life history of a key herbivore

Herbivore outbreaks often trigger catastrophic overgrazing events in marine macrophyte ecosystems. The sea urchin Paracentrotus lividus, the dominant herbivore of shallow Mediterranean seascapes, is capable of precipitating shifts to barrens when its populations explode. Paracentrotus lividus is found ubiquitously in rocky macroalgal communities and in sandy seagrass meadows of Posidonia oceanica, two of the most important subtidal habitats in the Mediterranean. We explored if habitat‐specific regulation across the principal stages of the urchin life cycle could help explain the persistence of these populations in connected mosaics. We measured each of three relevant ecological processes (i.e. settlement, post‐settlement survival and predation) across a wide stretch of the Mediterranean coast (ca 600 km). Our results show that habitat‐specific regulation is critical in determining urchin populations: each habitat limited urchin sub‐populations at different life stages. Settlement was never limiting; urchins settled at similar rates in both habitats across the coast. Post‐settlement survival was a clear bottleneck, particularly in seagrass meadows where no juvenile urchins were recorded. Despite this bottleneck in seagrasses, adult urchin populations were very similar in both seagrass and macroalgal habitats indicating that other processes (potentially migration) could be key in determining adult distributions across the mosaic. The fact that population regulation is clearly habitat‐specific suggests that sea urchin populations may be significantly buffered from bottlenecks in mixed seascapes where both habitats co‐occur. Sea urchin populations can therefore persist across the seascape despite strong habitat‐specific regulation either by maintaining reproductive output in one habitat or by migrating between them. By affording these regulatory escapes to habitat‐modifying species, patchy mosaics may be much more prone to herbivore outbreaks and a host of cascading effects that come in their wake.info:eu-repo/semantics/acceptedVersio

Intereses profesionales y selección de carrera: criterios para la implementación de diagnósticos de compatibilidad automatizados en la Universidad Politécnica Salesiana (ECUADOR)

El factor vocacional constituye un componente fundamental para las explicaciones formuladas en torno al abandono universitario. En este sentido, la Universidad Politécnica Salesiana – Ecuador (UPS) ha desarrollado, durante los últimos años, una estrategia sostenida para el fortalecimiento de sus procesos de orientación vocacional y profesional. En la primera etapa se elaboraron instrumentos propios para la medición de las características actitudinales de los aspirantes a la oferta académica institucional, entre estos el Cuestionario de Intereses Profesionales (CIPRO- UPS). Una vez concluida la etapa de depuración y validación psicométrica de dicho instrumento, obteniéndose su versión definitiva, surge la necesidad de definir criterios metodológicos para su implementación como herramienta de diagnóstico, destinada a evaluar el grado de ajuste entre las preferencias profesionales de los aspirantes universitarios y sus carreras de interés. Asimismo, la masificación de este procedimiento demanda la creación de una plataforma automatizada online que facilite al aspirante la identificación de programas de estudio más afines con su perfil vocacional- profesional, en el marco de la oferta educativa de la UPS. En consecuencia, el presente trabajo expone los resultados del proceso de construcción de criterios de evaluación para la aplicación del CIPRO- UPS, así como la elaboración de un prototipo de diagnóstico automatizado mediante hoja de cálculo, previo al desarrollo de una plataforma online de mayor alcance. El objetivo inicial consistió en establecer puntos de corte óptimos para los índices de preferencia por carrera producidos para la evaluación del ajuste vocacional, a partir de distintas combinaciones de los trece campos profesionales que evalúa el CIPRO-UPS. Esto se fundamentó en el análisis de curvas ROC tomando como criterio externo de pronóstico y discriminación al rendimiento académico. Se utilizó información de corte longitudinal, los datos relativos a la aplicación del CIPRO-UPS corresponden a los aspirantes que cursaron el proceso institucional de admisiones para acceder a las carreras ofertadas por la Sede Quito en el periodo académico 2017-2018. Posteriormente se hizo un seguimiento del rendimiento académico de esta cohorte durante los primeros tres niveles de estudio. Los puntos de corte para clasificar a los  estudiantes entre afines y no afines con una carrera determinada se estimaron mediante los siguientes pasos: a) definir de un perfil deseable por carrera, estableciendo a priori los campos profesionales del CIPRO-UPS que reflejan afinidad y detectando empíricamente aquellas escalas desfavorables en términos de rendimiento académico; b) asignar pesos relativos a las escalas compatibles y contraproducentes; c) construir un índice compuesto de ajuste vocacional por carrera; d) mediante curvas ROC establecer puntos de corte óptimos para dichos índices, de manera que maximicen la capacidad discriminativa entre estudiantes de rendimiento satisfactorio y no satisfactorio. Como objetivo final se efectuó una automatización preliminar del procedimiento de clasificación descrito, a partir de una hoja de cálculo, de manera que los aspirantes puedan visualizar de modo ágil y amigable aquellas carreras con las cuales mantienen afinidad según sus preferencias profesionales. Se discuten las implicaciones, limitaciones y recomendaciones del estudio

Contrasting effects of ocean warming on different components of plant-herbivore interactions

Este artículo contiene 11 páginas, 6 figuras, 1 tabla.There is increasing uncertainty of how marine ecosystems will respond to rising temperatures. While studies have focused on the impacts of warming on individual species, knowledge of how species interactions are likely to respond is scant. The strength of even simple two-species interactions is influenced by several interacting mechanisms, each potentially changing with temperature. We used controlled experiments to assess how plantherbivore interactions respond to temperature for three structural dominant macrophytes in the Mediterranean and their principal sea urchin herbivore. Increasing temperature differentially influenced plant-specific growth, sea urchin growth and metabolism, consumption rates and herbivore preferences, but not movement behaviour. Evaluating these empirical observations against conceptual models of plant-herbivore performance, it appears likely that while the strength of herbivory may increase for the tested macroalga, for the two dominant seagrasses, the interaction strength may remain relatively unchanged or even weaken as temperatures rise. These results show a clear set of winners and losers in the warming Mediterranean as the complex factors driving species interactions change.The Spanish Ministry of Science and Innovation funded this research (projects CMT2010-22273- C02-01-02 and CMT2013-48027-C03-R) and supported JB (scholarship BES-2011-043630). The Spanish National Research Council supported RA's visitorship (CSIC-201330E062). TS was supported by an Australian Government Endeavour Fellowship. JFP acknowledges financial support from the Welsh Government and Higher Education Funding Council for Wales through the Sȇr Cymru National Research Network for Low Carbon, Energy and Environment. Support to FT was provided by the Ramón y Cajal Programme (RYC-2011-08572).Peer reviewe