Reproduction in the externally brooding sea anemone Epiactis georgiana in the Antarctic Peninsula and the Weddell Sea

14 pages, 8 figures, 2 tablesExternal parental care is uncommon among actiniarians but common in Epiactis species. Here, several aspects of reproduction are analyzed for of one of them, Epiactis georgiana. Samples were collected in December, January, February, March, and April in the Antarctic Peninsula and the eastern Weddell Sea, during 1998, 2000, 2002, and 2003. Most sexually mature individuals of E. georgiana are male or female, but some are hermaphrodites. This is the first report of hermaphroditism in E. georgiana, which is the third species of the genus with this sexual pattern. The results suggest that oogenesis starts in December and that at least two generations of oocytes overlap; a third generation is often brooded externally. Putative fertilization is likely internal, and larvae and/or embryos are externally brooded on the distal part of the adult column until an advanced developmental stage. Apparently E. georgiana reproduces seasonally, probably releasing the embryos/larvae in the last months of the austral spring (December). Inter-individual variability was observed in gametogenesis. In addition, specimens from the Antarctic Peninsula were larger than those from the Weddell Sea. This study represents the first step in understanding the reproductive mode of E. georgianaSpecial thanks are addressed to Prof. Dr. Wolf Arntz (Alfred-Wegener-Institute, Bremerhaven, Germany) who made possible our participation in several Antarctic projects and cruises. We extend our acknowledgements to the officers and crew of the R/V Polarstern and many colleagues on board during the EASIZ, ANDEEP, and BENDEX cruises for their valuable assistance. Thanks to M. Conradi (Universidad de Sevilla) who collected a considerable amount of the material analyzed in this manuscript. Comments from M. Daly, D. Fautin, and an anonymous reviewer substantially improved this manuscript. Support was provided by a MCT-CSICgrant (I3P-BPD2001-1) to E. Rodríguez and Spanish CICYT projects: ANT97-1533-E, ANT98-1739-E, ANT99-1608-E, REN2001-4269-E/ANT, REN2003-04236, and CGL2004-20141-E. This is a contribution to the SCAR program, Ecology of the Antarctic Sea Ice Zone (EASIZ) and ANDEEP contribution 159Peer reviewe

Description of <i>Genesis vulcanoctopusi</i> gen. et sp. nov. (Copepoda: Tisbidae) parasitic on a hydrothermal vent octopod and a reinterpretation of the life cycle of cholidyinid harpacticoids

Juveniles and adult females of Genesis vulcanoctopusi gen. et sp. nov. (Copepoda: Harpacticoida) are described from the deepwater octopus Vulcanoctopus hydrothermalis, collected from a hydrothermal vent in the East Pacific Rise. The new genus is placed in the Tisbidae and is readily distinguishable from other Cholidyinae by the combination of body shape, structure of oral appendages and segmentation of legs 1-5. All stages were found embedded in the integument of the head and mantle of the cephalopod host, suggesting an endoparasitic copepodid phase. The generalized life cycle of cholidyinid harpacticoids is reinterpreted in the light of this discovery. Aspects of parasitism and pathological effects of G. Vulcanoctopusi on the octopod host are discussed

Geometrical structure of two-dimensional crystals with non-constant dislocation density

We outline mathematical methods which seem to be necessary in order to discuss crystal structures with non-constant dislocation density tensor(ddt) in some generality. It is known that, if the ddt is constant (in space), then material points can be identified with elements of a certain Lie group, with group operation determined in terms of the ddt - the dimension of the Lie group equals that of the ambient space in which the body resides, in that case. When the ddt is non-constant, there is also a relevant Lie group (given technical assumptions), but the dimension of the group is strictly greater than that of the ambient space. The group acts on the set of material points, and there is a non-trivial isotropy group associated with the group action. We introduce and discuss the requisite mathematical apparatus in the context of Davini's model of defective crystals, and focus on a particular case where the ddt is such that a three dimensional Lie group acts on a two dimensional crystal state - this allows us to construct corresponding discrete structures too

Explicit differential characterization of the Newtonian free particle system in m > 1 dependent variables

In 1883, as an early result, Sophus Lie established an explicit necessary and sufficient condition for an analytic second order ordinary differential equation y_xx = F(x,y,y_x) to be equivalent, through a point transformation (x,y) --> (X(x,y), Y(x,y)), to the Newtonian free particle equation Y_XX = 0. This result, preliminary to the deep group-theoretic classification of second order analytic ordinary differential equations, was parachieved later in 1896 by Arthur Tresse, a French student of S. Lie. In the present paper, following closely the original strategy of proof of S. Lie, which we firstly expose and restitute in length, we generalize this explicit characterization to the case of several second order ordinary differential equations. Let K=R or C, or more generally any field of characteristic zero equipped with a valuation, so that K-analytic functions make sense. Let x in K, let m > 1, let y := (y^1, ..., y^m) in K^m and let y_xx^j = F^j(x,y,y_x^l), j = 1,...,m be a collection of m analytic second order ordinary differential equations, in general nonlinear. We provide an explicit necessary and sufficient condition in order that this system is equivalent, under a point transformation (x, y^1, ..., y^m) --> (X(x,y), Y^1(x,y),..., Y^m(x, y)), to the Newtonian free particle system Y_XX^1 = ... = Y_XX^m = 0. Strikingly, the (complicated) differential system that we obtain is of first order in the case m > 1, whereas it is of second order in S. Lie's original case m = 1.Comment: 76 pages, no figur

Generic competences for the IT knowledge workers: a study from the field.

Proceedings of: Third World Summit on the Knowledge Society (WSKS 2010), Corfu, Greece, September 22-24, 2010This paper aims to identify generic competency levels relevant to a particular kind of knowledge workers: software engineers. Based on previous works, and in particular in the description of a professional career, authors review of the literature related to the characterization of the labor force in the Software Engineering (SE) domain. Subsequently, using a quantitative analysis based on investigative surveys administered to a number of representative professionals, authors provide with a generic competency ladder adapted to the given career description.Publicad

Diversity, structure and spatial distribution of megabenthic communities in Cap de Creus continental shelf and submarine canyon (NW Mediterranean)

The continental shelf and submarine canyon off Cap de Creus (NW Mediterranean) were declared a Site of Community Importance (SCI) within the Natura 2000 Network in 2014. Implementing an effective management plan to preserve its biological diversity and monitor its evolution through time requires a detailed character ization of its benthic ecosystem. Based on 60 underwater video transects performed between 2007 and 2013 (before the declaration of the SCI), we thoroughly describe the composition and structure of the main mega benthic communities dwelling from the shelf down to 400 m depth inside the submarine canyon. We then mapped the spatial distribution of the benthic communities using the Random Forest algorithm, which incor porated geomorphological and oceanographic layers as predictors, as well as the intensity of the bottom-trawling fishing fleet. Although the study area has historically been exposed to commercial fishing practices, it still holds a rich benthic ecosystem with over 165 different invertebrate (morpho)species of the megafauna identified in the video footage, which form up to 9 distinct megabenthic communities. The continental shelf is home to coral gardens of the sea fan Eunicella cavolini, sea pen and soft coral assemblages, dense beds of the crinoid Leptometra phalangium, diverse sponge grounds and massive aggregations of the brittle star Ophiothrix fragilis. The submarine canyon off Cap de Creus is characterized by a cold-water coral community dominated by the scleractinian coral Madrepora oculata, found in association with several invertebrate species including oysters, brachiopods and a variety of sponge species, as well as by a community dominated by cerianthids and sea urchins, mostly in sedimentary areas. The benthic communities identified in the area were then compared with habitats/biocenoses described in reference habitat classification systems that consider circalittoral and bathyal environments of the Mediterranean. The complex environmental setting characteristic of the marine area off Cap de Creus likely produces the optimal conditions for communities dominated by suspension- and filter-feeding species to develop. The uniqueness of this ecosystem and the anthropogenic pressures that it faces should prompt the development of effective management actions to ensure the long-term conservation of the benthic fauna representative of this marine area3,26

Multiwavelength studies of MHD waves in the solar chromosphere: An overview of recent results

The chromosphere is a thin layer of the solar atmosphere that bridges the relatively cool photosphere and the intensely heated transition region and corona. Compressible and incompressible waves propagating through the chromosphere can supply significant amounts of energy to the interface region and corona. In recent years an abundance of high-resolution observations from state-of-the-art facilities have provided new and exciting ways of disentangling the characteristics of oscillatory phenomena propagating through the dynamic chromosphere. Coupled with rapid advancements in magnetohydrodynamic wave theory, we are now in an ideal position to thoroughly investigate the role waves play in supplying energy to sustain chromospheric and coronal heating. Here, we review the recent progress made in characterising, categorising and interpreting oscillations manifesting in the solar chromosphere, with an impetus placed on their intrinsic energetics.Comment: 48 pages, 25 figures, accepted into Space Science Review

Informe de resultados de la campaña `Maurit-0911'. Estudio de los ecosistemas de la plataforma y margen contiental de Mauritania

Versión del edito

Revista de Vertebrados de la Estación Biológica de Doñana

Tiempo y orden de aparición de las escamas en el salmón del Atlántico (Salmo salar)Estudios sobre el sapo corredor (Bufo calamita) en el sur de España.III. ReproducciónInfluencia de las carecterísticas del medio acuático sobre las poblaciones de larvas de anfibios en lala Reserva Biológica de Doñana(Huelva, EspañaDieta de la cigüeñuela (Himantopus himantopus) en las salinas del estuario del GuadianaOrientación y selección del lugar del nido en el gorrión moruno (Passer hispaniolensis)la avifauna de las Vegas Bajas del Guadianala reproducción de la malvasía (Oxyura leucocephala) en el sur de la provincia de Córdoba, España.La alimentación de la curruca cabecinegra (Sylvia melanocephala, Gmelin 1788) en olivares de la provincia de Jaén (otoño-invierno)Consideraciones sobre el efecto de los conejos y los grandes herbívoros en los pastizales de la Vera de DoñanaAnálisis factorial de las expresiones faciales del babuino sagrado (Papio hamadryas)Contaminación xenobiótica del Parque Nacionalde Doñana. II. Residuos de insecticidas organoclorados, bifenilos policlorados, (PGBs) y metales pesados en Falconiformes y StrigiformesTransferencia total y del y bioacumulación de mercurio y metilmercurio en ecosistemas del Parque Nacional de DoñanaNota sobre la alimentación de larvas de anfibios: I. Pleurodeles waltl en charcas temporaleNota sobre nuevas especies parasitada por el críalo (Clamator glandarius) en EspañaEstructura de la jerarquización en la predación de huevos y pichones en Spheniscus magellanicusPasser domesticus, nueva specie para Bolivia¿Están realmente subalimentados los cernícalos primilla en el valle del Guadalquivir durante el periodo no reproductor?.Nidificación del paiño común (Hydrobates pelagicus) en las Islas Canarias.Nuevos datos sobre la presencia del visón europeo (Mustela lutreola L.) en NavarraLa población de gamos del Parque Nacional de Doñana en 1979Puntualización a la nota "predacción de Falco peregrino y Falco subbuteo sobre quirópteros" de Aymerich y García de Castro aparecida en el vol. 9 de esta revista.Peer reviewe

Caracterización del Banco de La Concepción

Se integra información hidrográfica, geomorfológica, sedimentológica, biológica, sobre hábitats marinos y pesquera, para establecer las bases ecológicas necesarias para la protección y conservación del Banco de La ConcepciónEl proyecto INDEMARES ha permitido utilizar amplios medios económicos y personales para estudiar en detalle y desde múltiples perspectivas la zona del Banco de La Concepción. Se han aplicado metodologías para el estudio de la hidrografía, caracterizando la región, describiendo sus principales masas de agua y la hidrodinámica de las corrientes. También se ha abordado la geología de la zona, incluyendo levantamientos batimétricos, perfiles sísmicos, muestreos de sedimento y petrológicos, obteniendo modelos digitales del terreno, mapas de tipos de fondo, geomorfológicos. Se han caracterizado las comunidades bentopelágicas, demersales, epibentónicas y endobentónicas, prestando especial atención a aquellas que conforman o estructuran los hábitats sensibles cuyo inventariado y cartografía era objeto principal del proyecto. Los trabajos de identificación de hábitats se han realizado con muestreadores directos, pero también con muestreadores visuales, que han permitido hacer un mayor esfuerzo de muestreo sin aumentar el impacto sobre los fondos de la zona. Por otro lado se ha estudiado la huella pesquera de la zona por medio del análisis de los datos VMS y los cuadernos de pesca proporcionados por la SGP, además de una ardua labor a pie de puerto de entrevistas y encuestas. Toda la información ha sido gestionada y analizada por diferentes grupos de investigación de diferentes centros (Universidad de La Laguna, Instituto Universitario de Ciencias Políticas y Sociales, Universidad de Las Palmas de Gran Canaria, Instituto de Ciencias del Mar de Barcelona, Universidad de Barcelona, Centro de Investigaciones Medioambientales del Atlántico, Centro Oceanográfico de Santander y Centro Oceanográfico de Málaga del Instituto Español de Oceanografía, …), aunque el grueso de esta labor, además de la coordinación, se ha llevado a cabo en el Centro Oceanográfico de Canarias del Instituto Español de Oceanografía. Los resultados permiten tener un conocimiento profundo y multidisciplinar de la zona de estudio comparable a pocos proyectos de investigación marina en la macaronesia. El estudio oceanográfico, el geológico, y el de las comunidades biológicas, ha permitido la caracterización de los hábitats de la zona, y su cartografiado mediante el intenso muestreo y la aplicación de análisis de idoneidad de hábitats.INDEMARES Project made possible to bring together economic and staff resources to study in detail, and from multiple perspectives, the area of Banco de La Concepción. Methodologies have been applied to study hydrography, making a regional characterization, depicting main water masses, and current hydrodynamics. Geology has been tackled including bathymetric uplifting, seismic profiles, sediment and petrological sampling, obtaining digital terrain models, type of bottom maps, geomorphological maps, as an output. Benthopelagic, demersal, epibenthic and endobenthic communities have been characterized, paying special attention to sensitive habitats which inventory and mapping was the project’s main aim. Habitat identification has been made with direct and visual samplers, the latter making a major sampling effort possible without an increase of bottom impact. Moreover, fisheries footprint has been identified by Vessel Monitoring System data, together with logbooks from Secretaría General de Pesca (Fisheries Ministry), as well as a hard interviewing and surveying task at landing points. Information has been managed and analysed by different research groups from different Centres (Universidad de La Laguna, Instituto Universitario de Ciencias Políticas y Sociales, Universidad de Las Palmas de Gran Canaria, Instituto de Ciencias del Mar de Barcelona, Universidad de Barcelona, Centro de Investigaciones Medioambientales del Atlántico, Centro Oceanográfico de Santander y Centro Oceanográfico de Málaga del Instituto Español de Oceanografía), although the main body of the work, plus coordination, has been made by the Canary Islands Oceanographic Centre, from the Spanish Institute of Oceanography. Results let us have a multidisciplinary profound knowledge of the study zone, comparable to few other marine research projects off Macaronesia. The study about oceanography, geology and biologic communities has allowed the habitats characterization and mapping by means of intensive sampling and habitat suitability analysis.Instituto Español de Oceanografía, Comisión Europea Programa LIFE+, Fundación Biodiversida