Population density and feeding habits of Oreaster reticulatus (Linnaeus, 1758) (Echinodermata, Asteroidea) living in seagrass beds off Venezuela

We determined the density and size ranges of individuals of the asteroid Oreaster reticulatus (Linnaeus, 1758) from three populations off the Venezuelan coast. Individuals were collected by hand, visually inspecting 100 m² quadrates in the localities of Caño León (N = 10), Las Luisas (N = 24), and Mochima (N = 5). In the field, each individual was turned upside down, in order to determine the condition of the asteroid's stomach (everted vs retracted), and to describe the substrate to which they were associated. Individuals were preserved and their gut contents were analyzed in the laboratory. Oreaster reticulatus (L., 1758) was found 65 % of the times on silt and in areas with low seagrass densities. At Las Luisas, the density of the asteroid was 0.0075 indiv/ m². However, in Caño León and Mochima, densities were at least one or two orders of magnitude higher, reaching 0.072 indiv/m² and 0.2 indiv/m², respectively. Size ranged between 4 and 9.3 cm at Las Luisas; 7.8 and 12.6 cm at Caño León; and 8.5 and 16.5 cm at Mochima. Of the 55 asteroids studied in Caño León, 63.64 % had the stomach everted on the silty substrate. Of these, 14.28 % were feeding on a colonial tunicate, and 71.34 %, on a filamentous alga. Spines of sea urchins were found in 19.05 % of all the specimens collected in Mochima. Previous observations, from laboratory experiments, have shown individuals of Oreaster reticulatus actively predating upon individuals of Lytechinus variegatus (Lamarck, 1818).Con la finalidad de determinar la densidad y talla del asteroideo Oreaster reticulatus (Linnaeus, 1758) presente en tres localidades de fanerógamas de Venezuela, se realizaron cuadrículas de 100 m² en las estaciones de Caño León (10), Las Luisas (24) y Mochima (5). La dieta de O. reticulatus (L., 1758) se determinó levantando cada uno de los ejemplares conseguidos y observando si el estómago se encontraba evertido y la naturaleza del sustrato. El asteroideo se encontró un 65 % de las veces sobre sedimento o en áreas de poca vegetación. La densidad en la localidad de Las Luisas fue de 0,0075 indiv/m², siendo un orden de magnitud mayor en Caño León (0,072 indiv/m²), mientras que Mochima presentó las mayores densidades (0,2 indiv/m²). De las 55 estrellas estudiadas en Caño León, un 63,64 % tenía el estómago evertido sobre el sedimento, mientras que un 12,73 % lo tenía sobre las hojas de las fanerógamas. En Mochima, un 14,28 % de los ejemplares se alimentaba de sedimento, un 14,28 % lo hacía sobre un tunicado colonial y un 71,34 % estaba sobre algas filamentosas. Del total observado en Mochima un 19,05 % presentaba espinas de erizos envueltas en el estómago. En laboratorio se realizaron experiencias de depredación sobre el erizo Lytechinus variegatus (Lamarck, 1818), comprobándose depredación activa sobre el mismo, en un periodo aproximado de 6 horas. La talla (radio mayor) de O. reticulatus osciló entre 4 y 9,3 cm en Las Luisas, entre 7,8 y 12,6 cm en Caño León y entre 8,5 y 16,5 cm en Mochima.Instituto Español de Oceanografí

Biodegradable PEG–dendritic block copolymers: synthesis and biofunctionality assessment as vectors of siRNA

One important drawback of most of the currently used dendrimers for biomedical applications is their high stability under physiological conditions that can result in cytotoxicity or complications induced by the accumulation of non-degradable synthetic materials in the organism. Particularly in the gene therapy field, vector stability can further hinder the intracellular release of the nucleic acid from the dendriplex, consequently leading to low transfection efficiencies. Therefore, biodegradable cationic dendritic structures have been eagerly awaited. However, the development of these dendritic nanocarriers is challenging because of the undesired and/or premature degradation observed during their synthesis and/or application. Here, we report new hybrid-biodegradable, biocompatible, non-toxic, and water-soluble azide-terminated PEG–GATGE dendritic block copolymers, based on a gallic acid (GA) core and triethylene glycol (TG) butanoate arms, incorporating ester bonds (E) at the dendritic arms/shell. Their successful functionalization by “click” chemistry with unprotected alkynated amines allowed complexation and delivery of siRNA. The hydrophobic character of the GATGE building unit confers to these hydrolyzable dendritic bionanomaterials a great ability to complex, protect and mediate the cellular internalization of siRNA. Moreover, the localization of the degradation points at the dendritic periphery, close to the complexed siRNA, was found to be important for nucleic acid release from the nanoparticles, rendering a significant improvement of the transfection efficiency compared to their hydrolytically stable PEG–GATG copolymer counterparts. The present study puts forward these biodegradable PEG–dendritic block copolymers not only as suitable vectors for nucleic acids, but also as new avenues for further developments exploring their use in theranosticsThe authors would like to acknowledge the FEDER funds through the Programa Operacional Factores de Competitividade – COMPETE and the Portuguese funds through FCT – Fundação para a Ciência e a Tecnologia (PTDC/CTM-NAN/112428/2009 and PTDC/CTM-NAN/3547/2014) that supported this work and the FCT / MEC through National Funds and, when applicable, co-financed by the FEDER via the PT2020 Partnership Agreement under the 4293 Unit I&D. V. Leiro acknowledges the support by FCT (SFRH/BPD/69110/2010) and by the project NORTE-01-0145-FEDER-000012, financed by Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF). P.M.D. Moreno acknowledges the support from the Marie Curie Actions of the European Community’s Seventh Framework Program (PIEF-GA-2011-300485) and FCT fellowship (SFRH/BPD/108738/2015). This work was also financially supported by the Spanish Government (MINECO: CTQ2012-34790, CTQ2012-33436) and the Xunta de Galicia (CN2011/037)S

Estudio de crecimiento y producción de toxinas en tres especies de Alexandrium: A. catenella, A. peruvianum y A. ostenfeldii.

Se estudió el crecimiento y el contenido en toxinas de 3 especies de dinoflagelados: Alexandrium catenella, A. peruvianum y A. ostenfeldii. A. catenella mostró tasas de crecimiento más elevadas que las otras dos especies. Las tres especies crecieron más rápidamente a 26ºC y menos a 15ºC aunque las tasas de crecimiento no mostraron grandes diferencias. Se observaron diferentes ventanas óptimas de crecimiento en relación a la salinidad en las tres especies. Las máximas tasas de crecimiento fueron a 32 y 37 de salinidad para A. catenella, a 25 de salinidad para A. peruvianum y a 10 de salinidad para A. ostenfeldii. Las tres especies produjeron toxinas PSP pero en muy diferentes cantidades, mostrando notables diferencias en el perfil de toxinas: (10 componentes A. catenella: C1, C2, GTX1-6, neoSTX y STX; 3 componentes A ostenfeldii y A. peruvianum: GTX2-3 y STX). La concentración de toxinas PSP en A. peruvianum fue muy baja. Se detectó también presencia de espirólidos (13-Desmetil-SPX C) en A. peruvianum y Gymnodimina-A en A. ostenfeldii

Age and date for early arrival of the Acheulian in Europe (Barranc de la Boella, la Canonja, Spain)

The first arrivals of hominin populations into Eurasia during the Early Pleistocene are currently considered to have occurred as short and poorly dated biological dispersions. Questions as to the tempo and mode of these early prehistoric settlements have given rise to debates concerning the taxonomic significance of the lithic assemblages, as trace fossils, and the geographical distribution of the technological traditions found in the Lower Palaeolithic record. Here, we report on the Barranc de la Boella site which has yielded a lithic assemblage dating to ,1 million years ago that includes large cutting tools (LCT). We argue that distinct technological traditions coexisted in the Iberian archaeological repertoires of the late Early Pleistocene age in a similar way to the earliest sub-Saharan African artefact assemblages. These differences between stone tool assemblages may be attributed to the different chronologies of hominin dispersal events. The archaeological record of Barranc de la Boella completes the geographical distribution of LCT assemblages across southern Eurasia during the EMPT (Early-Middle Pleistocene Transition, circa 942 to 641 kyr). Up to now, chronology of the earliest European LCT assemblages is based on the abundant Palaeolithic record found in terrace river sequences which have been dated to the end of the EMPT and later. However, the findings at Barranc de la Boella suggest that early LCT lithic assemblages appeared in the SW of Europe during earlier hominin dispersal episodes before the definitive colonization of temperate Eurasia took place.The research at Barranc de la Boella has been carried out with the financial support of the Spanish Ministerio de Economı´a y Competitividad (CGL2012- 36682; CGL2012-38358, CGL2012-38434-C03-03 and CGL2010-15326; MICINN project HAR2009-7223/HIST), Generalitat de Catalunya, AGAUR agence (projects 2014SGR-901; 2014SGR-899; 2009SGR-324, 2009PBR-0033 and 2009SGR-188) and Junta de Castilla y Leo´n BU1004A09. Financial support for Barranc de la Boella field work and archaeological excavations is provided by the Ajuntament de la Canonja and Departament de Cultura (Servei d’Arqueologia i Paleontologia) de la Generalitat de Catalunya. A. Carrancho’s research was funded by the International Excellence Programme, Reinforcement subprogramme of the Spanish Ministry of Education. I. Lozano-Ferna´ndez acknowledges the pre-doctoral grant from the Fundacio´n Atapuerca. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Transmutation in ADS and needs for nuclear data, with an introduction to the n-TOF at CERN

Transmutation can help in the nuclear waste problem by reducing seriously the life and amount of the most dangerous isotopes (radiotoxicity, heat, packing volume and neutron multiplication reductions). ADS are one of the best technologies for nuclear waste transmutation at large scale. Although enough information is available to prepare conceptual designs and make assessments on their performance, a large R&D campaign is required to obtain the precision data required to optimize the detailed engineering design and refine our expectations calculations on waste reduction by the different transmutation strategies being proposed. In particular a large R&D effort is required in nuclear physics, where fundamental differential measurements and integral verification experiments are required. In this sense, the PS213 n-TOF at CERN PS (at Switzerland) will become one of the largest installations to perform the fundamental differential measurements and a wide international collaboration has been setup to perform the cross section measuring campaign. Similarly, the MUSE and several other experiments taking place and in preparation in Europe, USA and Japan will provide the integral verification. (6 refs)

Estudio de crecimiento y producción de toxinas en tres especies de Alexandrium: A. catenella, A. peruvianum y A. ostenfeldii

XII Reunión Ibérica sobre Microalgas Nocivas y Biotoxinas, 17-18 de octubre de 2013, Palma de MallorcaSe estudió el crecimiento y el contenido en toxinas de 3 especies de dinoflagelados: Alexandrium catenella, A. peruvianum y A. ostenfeldii. A. catenella mostró tasas de crecimiento más elevadas que las otras dos especies. Las tres especies crecieron más rápidamente a 26ºC y menos a 15ºC aunque las tasas de crecimiento no mostraron grandes diferencias. Se observaron diferentes ventanas óptimas de crecimiento en relación a la salinidad en las tres especies. Las máximas tasas de crecimiento fueron a 32 y 37 de salinidad para A. catenella, a 25 de salinidad para A. peruvianum y a 10 de salinidad para A. ostenfeldii. Las tres especies produjeron toxinas PSP pero en muy diferentes cantidades, mostrando notables diferencias en el perfil de toxinas: (10 componentes A. catenella: C1, C2, GTX1-6, neoSTX y STX; 3 componentes A ostenfeldii y A. peruvianum: GTX2-3 y STX). La concentración de toxinas PSP en A. peruvianum fue muy baja. Se detectó también presencia de espirólidos (13-Desmetil-SPX C) en A. peruvianum y Gymnodimina-A en A. ostenfeldiiN

miniBELEN: A modular neutron counter for (, ) reactions

miniBELEN is a modular and transportable neutron moderated counter with a nearly flat neutron detection efficiency up to 10 MeV. Modularity implies that the moderator can be reassembled in different ways in order to obtain different types of response. The detector has been developed in the context of the Measurement of Alpha Neutron Yields (MANY) collaboration, which is a scientific effort aiming to carry out measurements of (, ) production yields, reaction cross-sections and neutron energy spectra. In this work we present and discuss several configurations of the miniBELEN detector. The experimental validation of the efficiency calculations using 252Cf sources and the measurement of the 27Al(, ) 30P reaction is also presented