2,193 research outputs found

    First record of the sea cucumber Parastichopus tremulus Gunnerus, 1767 (Echinodermata: Holothuroidea: Aspidochirotida) in the Mediterranean Sea (Alboran Sea, western Mediterranean)

    Get PDF
    The holothurian Parastichopus tremulus, a species only know from the north-eastern Atlantic, is reported for the first time from the Mediterranean Sea. Five individuals of the species were collected in the vicinity of the Seco de los Olivos sea mount in May 2017 from a bottom trawl sample carried out during the MEDITS trawl survey. Scanning Electron Microscope images of body wall ossicles are supplied to support species identification. Connectivity between Atlantic and Mediterranean populations of P. tremulus is suggested due to the existence of a nearby Atlantic population in the Gulf of Cádiz and the documented presence of abundant holothuroid larvae in the anticyclonic gyre which originates in the Atlantic current entering the Mediterranean, near the Strait of GibraltarPremier signalement du concombre de mer Parastichopus tremulus (Gunnerus, 1767) (Echinodermata : Aspidochirotida) en Méditerranée (Mer d’Alboran, Méditerranée occidentale). L’holothurie Parastichopus tremulus, une espèce connue seulement du nord-est Atlantique, est signalée pour la première fois en Mer Méditerranée. Cinq individus de l’espèce ont été récoltés près du mont sous-marin Seco de los Olivos en mai 2017 d’un échantillon de chalut de fond effectué pendant la campagne de recherche avec chalut MEDITS. Des photographies au microscope électronique à balayage d’osselets de la paroi du corps sont fournies pour valider l’identification de l’espèce. La connectivité entre les populations atlantiques et méditerranéennes de P. tremulus est suggérée en raison de la proximité d’une population atlantique dans le Golfe de Cádiz et de la présence documentée de larves d’holothurie abondantes dans le vortex anticyclonique originaire du courant atlantique entrant en Méditerranée, près du Détroit de GibraltarVersión del edito

    Preliminary characterization of echinoderm assemblages in circalittoral and bathyal soft bottoms of the northern Alboran Sea

    Get PDF
    Echinoderms, with 7.272 species described so far (based on WORMS), provide an ecosystemic role which can be important depending on their habitat, and including tag species (Manjón-Cabeza et al., 2014; Palma-Sevilla 2015) or even dominant ones (Iken et al., 2010; Hughes et al., 2012). Despite the increasing knowledge on their taxonomy, studies on ecological and assemblage composition and structure of echinoderms are very scarce compared to those for other invertebrate groups, being this information essential for improving the knowledge on Mediterranean ecosystems (Coll et al., 2010). The Alboran Sea, in the junction of the Atlantic Ocean and the Mediterranean Sea and the European and African continental margins, represents a biodiversity hotspot due to the overlapping of species from those basins and continents, including some endemic components (Coll et al., 2010). Regarding echinoderms of the Alboran Sea, most previous studies focussed on infralittoral bottoms, with very few for circalittoral and bathyal ones (Manjón-Cabeza et al, 2014; Sibuet, 1974). Nevertheless, these studies generally included faunistic lists (Ocaña & Pérez-Ruzafa, 2004; Manjón-Cabeza et al., 2014), sometimes with identification keys, ecological and distributional data of some species and rarely on the assemblage composition and structure (Palma-Sevilla, 2015), which represent the main aim of this study on echinoderm assemblages of circalittoral and bathyal soft bottoms of the Alboran Sea. During the MEDITS survey expeditions (April-May 2014-2015) on board the R/V Miguel Oliver (Fig. 1), 35 samples were collected using a beam trawl (horizontal and vertical openings of 1.3 and 1.2 m, respectively, and a mesh size of 10 mm in the codend) at depths from 40 to 774 m in the Alboran Sea (Fig. 1). Hauls were done at a speed of ca. 2 knots during 5-10 (shelf stations) and 15 minutes (slope stations). Echinoderms were separated, identified to the lowest possible taxonomic leveland specimens counted and weighed to the nearest 0.5 g. Abundance and biomass data were standardized to 1000 m2 according to the sampling area of each haul. Echinoderm assemblages were characterized according to the dominance and frequency of occurrence of species in the samples and considering different ecological indexes. Multivariate methods (CLUSTER, nMDS, SIMPER, ANOSIM) were applied, based on the Bray & Curtis similarity index, for detecting and contrastingassemblages in relation to depth and 4 geographic areas of the Alboran Sea with different influence of Atlantic waters (Occidental-Esteponato Málaga, Central-Málaga to Motril, Oriental-Motril to Almería and Alboran Island). Fig. 1. Location of beam-trawl samples (dots) collected during 2014 and 2015 MEDITS expeditions in the northern Alboran Sea. At present 39 taxa have been detected, mostly belonging to Ophiuroidea and Asteroidea (28.2 and 25.6% of all species, respectively), followed by Holothuroidea (23.1%), Echinoidea (17.9%) and Crinoidea (5.1%). Regarding abundance, a total of 54689 individuals have been collected, being Ophiuroidea (98.6% of all individuals), Holothuroidea (0.6%) and Crinoidea (0.4%) the top-dominant classes. Regarding biomass, ophiuroids also dominated (52.8%), followed by asteroids (16.1%) and holothuroids (15.0%). Considering other faunistic groups, echinoderms were the most abundant phyllum in the samples (60.7%) and the fifth one in biomass (7.6%). The dominant (for both abundance and biomass) and frequent genera included Ophiocten (displaying dominances >90%) Hymenodiscus, Luidia and Astropecten for asteroids, Antedon and Leptometra for crinoids, Dendrochirotida and Molpadidae for holothuroids, and Brissopsis and Echinocyamus for echinoids (Fig. 2). Fig. 2. Some echinodermscollected in circalittoral and bathyal soft bottoms of the Alboran Sea using beam-trawl during the MEDITS expeditions. A: Ophiocten; B: Dendrochirotida sp.; C: Brissopsis; D: Anseropoda; E: Luidia. Multivariate analyses indicated groupings of samples and significantly different echinoderm assemblages in relation to depth (RANOSIM=0.22, p0.05). Shelf assemblages displayed lower intra-group similarities (<20% similarity in SIMPER) than the slope ones (ca. 40%). Species characterizing the shelf assemblages belonged to the genera Astropecten, Antedon, Ophiothrix among others, whereas those of the slope belonged to the genera Luidia (L. sarsi), Hymenodiscus, Ophiocten, Leptometra and Amphiura

    Seismology of beta Cephei stars: differentially-rotating models for interpreting the oscillation spectrum of nu-Eridani

    Get PDF
    A method for the asteroseismic analysis of beta Cephei stars is presented and applied to the star nu Eridani. The method is based on the analysis of rotational splittings, and their asymmetries using differentially-rotating asteroseismic models. Models with masses around 7.13 M_sun, and ages around 14.9 Myr, were found to fit better 10 of the 14 observed frequencies, which were identified as the fundamental radial mode and the three L=1 triplets g, p, and p. The splittings and aymmetries found for these modes recover those provided in the literature, except for p. For this last mode, all its non-axysimmetric components are predicted by the models. Moreover, opposite signs of the observed and predicted splitting asymmetries are found. If identification is confirmed, this can be a very interesting source of information about the internal rotation profile, in particular in the outer regions of the star. In general, the seismic models which include a description for shellular rotation yield slightly better results as compared with those given by uniformly-rotating models. Furthermore, we show that asymmetries are quite dependent on the overshooting of the convective core, which make the present technique suitable for testing the theories describing the angular momentum redistribution and chemical mixing due to rotationally-induced turbulence.Comment: 11 pages, 9 figures, 8 tables. ApJ (in press

    Unveiling the power spectra of δ\delta Scuti stars with TESS. The temperature, gravity, and frequency scaling relation

    Get PDF
    Thanks to high-precision photometric data legacy from space telescopes like CoRoT and Kepler, the scientific community could detect and characterize the power spectra of hundreds of thousands of stars. Using the scaling relations, it is possible to estimate masses and radii for solar-type pulsators. However, these stars are not the only kind of stellar objects that follow these rules: δ\delta Scuti stars seem to be characterized with seismic indexes such as the large separation (Δν\Delta\nu). Thanks to long-duration high-cadence TESS light curves, we analysed more than two thousand of this kind of classical pulsators. In that way, we propose the frequency at maximum power (νmax\nu_{\rm max}) as a proper seismic index since it is directly related with the intrinsic temperature, mass and radius of the star. This parameter seems not to be affected by rotation, inclination, extinction or resonances, with the exception of the evolution of the stellar parameters. Furthermore, we can constrain rotation and inclination using the departure of temperature produced by the gravity-darkening effect. This is especially feasible for fast rotators as most of δ\delta Scuti stars seem to be.Comment: 12 pages, 13 figures, accepted in Astronomy & Astrophysic

    Aphid-borne viruses infecting cultivated watermelon and squash in Spain: characterization of a variant of cucurbit aphid-borne yellows virus (CABYV)

    Get PDF
    [SPA] Los virus transmitidos por pulgones son responsables de las principales enfermedades de cucurbitáceas. El continuo seguimiento de estos cultivos puede ayudar a prevenir la aparición y distribución de estos, facilitando el control de enfermedades. Durante tres temporadas (2018-2020) se examinó la presencia de virus transmitidos por pulgón en plantas de sandía y calabaza en tres zonas productoras de cucurbitáceas en España. El virus del amarilleo de las cucurbitáceas transmitido por pulgón (CABYV) fue mayoritario (29%) en ambos cultivos, seguido del virus del mosaico de la sandía (WMV) (23%). Se observaron unas plantas de sandía con síntomas más graves acompañados de aborto en los frutos revelando que CABYV era el agente causante de estos síntomas. Se construyeron dos clones de ADNc infecciosos (uno de sandía CABYV-LP63 y otro de melón CABYV-MEC12.1) para comparar y caracterizar esta nueva variante de CABYV. El estudio filogenético reveló que ambos aislados estaban dentro de la rama mediterránea. El aislado LP63 tiene dos eventos potenciales de recombinación en comparación con MEC12.1. Además, esta nueva variante causó síntomas más graves y presentó mayor acumulación en cinco especies de cucurbitáceas. Una nueva variante de CABYV causa síntomas de amarilleos más graves puede estar amenazando los cultivos de cucurbitáceas. [ENG] Aphid-borne viruses are responsible for major cucurbit diseases. Systematic monitoring can reveal the occurrence and distribution of these viruses, facilitating the control of diseases. During three seasons (2018-2020), the presence of aphid-borne viruses was controlled in watermelon and squash plants in three cucurbit-producing areas (Castilla La-Mancha, Alicante and Murcia) in Spain. Cucurbit aphid-borne yellows virus (CABYV) was the most common virus found (29%) in the plants from both crops. Likewise, except for squash samples from Castilla La-Mancha and Alicante, watermelon mosaic virus (WMV) was also found (23%) with a relatively high frequency. In addition, we observed more exacerbation symptoms in watermelon plants that was often accompanied by a fruit abortion. CABYV was the causative agent of this new disease; two infectious cDNA clones (one from watermelon CABYV-LP63 and one from melon CABYV-MEC12.1) were constructed to compare and characterize this disease. The phylogenetic study revealed that both isolates were within the Mediterranean branch. Isolate LP63 shows two potential recombination events compared to MEC12.1. LP63 isolate caused more severe symptoms and showed higher RNA accumulation than MEC12.1 in five cucurbits plant species. These results suggest that a novel CABYV variant that causes severe yellowing symptoms, may be causing outbreaks in cucurbit crops.Ministerio de ciencia, innovación y universidades con beca de doctorado (PRE2018-083915). AGL2017-89550-R de la Agencia Estatal de Investigación (AEI) y fondos FEDER (UE)

    Sleep during the third trimester of pregnancy: the role of depression and anxiety

    Get PDF
    Depression has been associated with sleep disturbances in pregnancy; however, no previous research has controlled the possible confounding effect of anxiety on this association. This study aims to analyze the effect of depression on sleep during the third trimester of pregnancy controlling for anxiety. The sample was composed by 143 depressed (n = 77) and non-depressed (n = 66) pregnant women who completed measures of depression, anxiety, and sleep. Differences between groups in sleep controlling for anxiety were found. Depressed pregnant women present higher number of nocturnal awakenings and spent more hours trying falling asleep during the night and the entire 24 h period. Present findings point out the effect of depression on sleep in late pregnancy, after controlling for anxiety.This research was supported by FEDER Funds through the Programa Operacional Factores de Competitividade - COMPETE and by National Funds through FCT – Fundação para a Ciência e a Tecnologia under the project: PTDC/SAU/SAP/116738/2010

    Asteroseismology with the WIRE satellite. I. Combining Ground- and Space-based Photometry of the Delta Scuti Star Epsilon Cephei

    Get PDF
    We have analysed ground-based multi-colour Stromgren photometry and single-filter photometry from the star tracker on the WIRE satellite of the delta scuti star Epsilon Cephei. The ground-based data set consists of 16 nights of data collected over 164 days, while the satellite data are nearly continuous coverage of the star during 14 days. The spectral window and noise level of the satellite data are superior to the ground-based data and this data set is used to locate the frequencies. However, we can use the ground-based data to improve the accuracy of the frequencies due to the much longer time baseline. We detect 26 oscillation frequencies in the WIRE data set, but only some of these can be seen clearly in the ground-based data. We have used the multi-colour ground-based photometry to determine amplitude and phase differences in the Stromgren b-y colour and the y filter in an attempt to identify the radial degree of the oscillation frequencies. We conclude that the accuracies of the amplitudes and phases are not sufficient to constrain theoretical models of Epsilon Cephei. We find no evidence for rotational splitting or the large separation among the frequencies detected in the WIRE data set. To be able to identify oscillation frequencies in delta scuti stars with the method we have applied, it is crucial to obtain more complete coverage from multi-site campaigns with a long time baseline and in multiple filters. This is important when planning photometric and spectroscopic ground-based support for future satellite missions like COROT and KEPLER.Comment: 13 pages, 12 figures, 4 tables. Fig. 4 reduced in quality. Accepted by A&

    Diagnosis, management, and outcomes of patients with syncope and bundle branch block

    Get PDF
    Although patients with syncope and bundle branch block (BBB) are at high risk of developing atrio-ventricular block, syncope may be due to other aetiologies. We performed a prospective, observational study of the clinical outcomes of patients with syncope and BBB following a systematic diagnostic approach. Patients with ≥1 syncope in the last 6 months, with QRS duration ≥120 ms, were prospectively studied following a three-phase diagnostic strategy: Phase I, initial evaluation; Phase II, electrophysiological study (EPS); and Phase III, insertion of an implantable loop recorder (ILR). Overall, 323 patients (left ventricular ejection fraction 56 ± 12%) were studied. The aetiological diagnosis was established in 267 (82.7%) patients (102 at initial evaluation, 113 upon EPS, and 52 upon ILR) with the following aetiologies: bradyarrhythmia (202), carotid sinus syndrome (20), ventricular tachycardia (18), neurally mediated (9), orthostatic hypotension (4), drug-induced (3), secondary to cardiopulmonary disease (2), supraventricular tachycardia (1), bradycardia-tachycardia (1), and non-arrhythmic (7). A pacemaker was implanted in 220 (68.1%), an implantable cardioverter defibrillator in 19 (5.8%), and radiofrequency catheter ablation was performed in 3 patients. Twenty patients (6%) had died at an average follow-up of 19.2 ± 8.2 months. In patients with syncope, BBB, and mean left ventricular ejection fraction of 56 ± 12%, a systematic diagnostic approach achieves a high rate of aetiological diagnosis and allows to select specific treatment
    corecore