381 research outputs found

    First faunistic results on Valencia (Cresques) Seamount, with some ecological considerations

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    The living and dead fauna of Valencia Seamount, a deep promontory in the middle of the Balearic Basin which summit is at ca. 1100m depth, is described by first time based in a rock dredge perfomed in a sedimentary area of the summit Mount. Surface-feeder polychaetes (the Paraonidae Levinsenia gracilis and Terebellidae as dominant), and taxodont bivalves (Ledella messanensis and Yoldiella ovulum) were the main species of benthos. We found alive remains of the bamboo coral Isidella elongata, a vulnerable, habitat-forming species in the deep Mediterranean. Benthos density was low (0.6 organisms/2 dm3 mud). Thanatocoenosis evidenced a rather moderate diversity on benthic bivalves (11 species) and gastropods (9 species) also dominated by surface deposit feeders. Fish (identified/ quantified from sedimented otoliths) showed diversified and abundant mesopelagic fauna, mainly Myctophidae. More interestingly, we highlighted among benthopelagic fish the occurrence of recruits of Merluccius merluccius, Micromesistius poutassou, or Hymenocephalus italicus, all species that live in the neighboring slopes of the Iberian Peninsula and the Balearic Islands at quite shallower depths (at 100-700 m) than their distribution in the Valencia Seamount summit (1102–1130 m) based on the deposited otoliths found. Some ecological aspects were discussed and the necessity to consider the deep Valencia Seamount as a potential area that should be under protection.En prensa

    Habitat use by Gadiculus argenteus (Pisces, Gadidae) in the Galician and Cantabrian Sea waters (NE Atlantic)

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    Forage fish species play a crucial role in most ecosystems, transferring energy from plankton to larger fishes. Therefore, understanding the factors driving the dynamics of forage fish populations is essential in marine ecosystems. Gadiculus argenteus is an important forage fish species in the Galicia and Cantabrian Sea ecosystem. In this study, the influence of several biotic and abiotic factors on the distribution of this species was examined using generalized additive models in a 2-step approach. G. argenteus habitat preference was not affected by changes in annual abundance during the study period (1998-2019). From the variables selected in the final models, depth and geographic location (latitude and longitude) were the most important factors to describe the presence of G. argenteus. Peak abundance was found on the upper slope and although the species was found throughout the study area, its higher abundance values were located in Galician waters. The species seemed to avoid coarse sand bottoms, with mean chlorophyll a concentration showing a positive effect on the presence and abundance of G. argenteus. Interestingly, the observed aggregations of G. argenteus showed a remarkable similarity to the commercial trawling footprint in the area, suggesting a strong link between the distribution of this forage species and the distribution of its predators, most of which are important commercial species. Further work should focus on a better understanding of this relationship to provide important information on the study of the structure and functioning of the marine ecosystem of the northern Spanish continental shelf.Versión del editor2,48

    Demersal and epibenthic communities of sedimentary habitats in the Avilés Canyon System, Cantabrian Sea (NE Atlantic)

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    The aim of this study was to describe the epibenthic and demersal communities of the Avilés Canyon System (ACS) in relation to the environmental variables that characterize their biotope. ACS (Cantabrian Sea, NE Atlantic) was recently included in the Natura 2000 network as a Site of Community Importance (SCI). Data of faunal biomass derived from 6 surveys carried out using beam trawl and otter trawls in 2009 and 2010 within INDEMARES and ERDEM projects. Data were divided into two groups to obtain information about the two ecological compartments: benthic and demersal. The total number of species used in this analysis ascended to 116 in the case of benthic organisms and 110 in the case of demersal. Hierarchical clustering analysis was applied to obtain groups of samples similar in terms of species composition for the two ecological components. Depth was the main discriminating factor for grouping hauls, showing high consistency of bathymetric range independently from the compartment examined. Six groups were identified by depth as follows: medium shelf (∼100–200 m), external shelf (∼150–300m), shelf break (∼300–400 m), upper-slope (∼500–700 m), upper middle-slope (∼700–1100 m), and lower-middle-slope (1200–1500 m). SIMPER analysis on biomass values was performed to determine the structure of the faunal assemblages observed for each group in both compartments. Using biomass values for the analysis allowed for the exploration of groups playing important roles in ecosystem functioning and energy fluxes taking place on the sedimentary bottom of this SCI. Finally, CCA analysis revealed that the main environmental drivers were depth, broad scale bathymetric position index (BPI), near-bottom salinity, sedimentary type, and dynamics related variables (Q50 phy and So). This study gives an inventory of the soft bottom assemblages along a very wide depth range (100–1500 m) inside a SCI, linking both epibenthic and demersal communities with the biotope preferences. This study contributes to fundamental knowledge on soft-bottom communities as a pre-requisite, necessary for the next steps in terms of management framework in the SCI

    Differential processing of anthropogenic carbon and nitrogen in benthic food webs of A Coruña (NW Spain) traced by stable isotopes

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    proyectos ANILE (CTM2009- 08396 and CTM2010-08804-E) del Plan Nacional de I+D+i y RADIALES del Instituto Español de Oceanografía (IEO). C.M. e I.G.V. disfrutaron de contratos FPI del IEO y del Ministerio de Economía y Competividad respectivamente.In this study the effect of inputs of organic matter and anthropogenic nitrogen at small spatial scales were investigated in the benthos of the Ria of A Coruña (NW Spain) using stable carbon and nitrogen isotopes. This ria is characteristically enriched in nutrients provided either by marine processes (as coastal upwelling) or by urban and agricultural waste. Stable isotope composition in trophic guilds of infaunal benthos revealed spatial differences related to their nutrient inputs. The main difference was the presence of an additional chemoautotrophic food web at the site with a large accumulation of organic matter. The enrichment in heavy nitrogen isotopes observed in most compartments suggests the influence of sewage-derived nitrogen, despite large inputs of marine nitrogen. Macroalgae (Fucus vesiculosus) resulted significantly enriched at the site influenced by estuarine waters. In contrast, no differences were found in mussels (Mytilus galloprovincialis), thus suggesting a major dependence on marine nutrient sources for this species. However, the estimations of anthropogenic influence were largely dependent on assumptions required to model the different contributions of sources. The measurement of stable isotope signatures in various compartments revealed that, despite anthropogenic nutrients are readily incorporated into local food webs, a major influence of natural marine nutrient sources cannot be discarded.IEO, Plan nacional I+D+iPreprint2,277

    Valoración funcional en pacientes intervenidos medianteplastia de LCA con semitendinoso-recto interno y sistema Togglelock.

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    Introducción: Una de las lesiones más frecuente de la rodilla y que está en aumento, sobre todo en el ámbito deportivo es la lesión del ligamento cruzado anterior. La reconstrucción quirúrgica es fundamental para recuperar la biomecánica de la rodilla, proporcionar una correcta estabilidad y funcionamiento libre de dolor, así como evitar cambios degenerativos tempranos. El objetivo del presente estudio fue valorar la recuperación funcional de los pacientes sometidos a una reconstrucción del ligamento cruzado anterior mediante ligamentoplastia con tendón semitendinoso-recto interno y sistema Toggelock. Material y métodos: Se diseñó un estudio retrospectivo descriptivo observacional, en el que se incluyeron a 29 pacientes a los cuales se les realizó una ligamentoplastia con semitendinoso-recto interno y sistema Togglelock en nuestro Centro, durante los años 2017-2018. Se estudiaron variables obtenidas de la historia clínica y la escala de Lysholm para la valoración del paciente. Resultados: En total, se obtuvo una muestra de 29 pacientes, 26 hombres y 3 mujeres con una media de edad de 31,13 años (rango 19-53). La rodilla más frecuentemente lesionada fue la derecha en 17 pacientes de 29, presentando lesiones asociadas el 65%. Una paciente había sufrido una fractura tibial intervenida con un clavo endomedular que alteró los resultados finales. La puntuación postquirúrgica de la escala de valoración subjetiva de Lysholm fue de 86. La movilidad de la rodilla intervenida presentó una reducción mínima de flexión de 6º en comparación con la rodilla no operada estadísticamente significativa. Conclusión: Los resultados obtenidos tras la reconstrucción del LCA con dicha técnica, utilizando la plastia del semitendinoso-recto interno y sistema Togglelock fueron buenos-excelentes, con un alto grado de satisfacción en los pacientes, escasas complicaciones y con resultados funcionales notables

    Infaunal macrobenthos in the Porcupine Bank (NE Atlantic)

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    The results of the macroinfaunal communities distributions from the annual series surveys PORCUPINE are shown. Those surveys were realized during the months of September and October in the years 2006, 2008, 2009, 2010, 2011, 2012 and 2013 by the Instituto Español de Oceanografía aboard the R /V Vizconde de Eza, within the research project ERDEM. This survey series has as main objective the obtainment of abundance indexes of the benthonic and demersal fauna from Porcupine Bank, west of Ireland, with special attention on the commercial species exploited by the Spanish fleet (hake, angler fish, megrim and norwegian lobster). For the study of the infaunal macrobenthos a total of 50 samples were analyzed from selected places of the Bank, where the bottom characteristics, the climatology or the survey schedule allowed. Samples were taken with an ULSNER box corer with 0.09 m2 of sampling area. Samples for the faunal study were sieved aboard with a 0.5 mm mesh size sieve. The material collected in the sieve was preserved with 8 % formaldehyde neutralized with borax, and stained with Rose Bengal solution for the posterior sorting and identification of fauna. Additional samples were taken to estimate the organic content of the sediment and to perform the granulometric analyses. Once in the laboratory, the granulometry was analyzed following the method recommended by Buchanan (1984); which consists in a combination of dry sieving of the coarse fraction (> 62 µm) and the sedimentation at 20 ºC of the fine fraction (< 62 µm) in a distilled water column. Sediment organic matter content was calculated as the percentage of weight loss by means of 24 hours sample calcination at 500 ºC, after dried it at 100 ºC during the same time. Complementary, in order to obtain a better coverage of the sedimentary types from the study area, more than 350 samples were collected with a net collector coupled to the trawling fishing gear (Baca-GAV 39/52). Globally, the sediments of the majority of the sampled stations are mainly formed by sand, between fine and very fine, except in deep areas of the southeast, where there are large muddy areas with elevated organic content and high selection coefficient. In the north, around the shallowest area, we found thicker sandy sediments, with lower organic content and moderate selection. The macroinfaunal communities from the Porcupine Bank are characterized by the dominance of the faunistic group of polychaetes (68.8 %), mainly represented by the families Owenidae, Spionidae, Paraonidae and Sabellidae. The next in number are the group of molluscs (17.6 %), dominated by the family Kelliellidae, which reaches maximum abundances up to 7520 ind•m-2. The poorest represented groups are the crustaceans (5.0 %), echinoderms (4.3 %) and the “others” (sipunculids, nemertine, etc.), being the latter the least abundant (3.7 %). In relation with the spatial distribution four macroinfaunal groups were indentified in the Porcupine Bank: - Group 1: located in intermediate depth areas, over sandy sediments with low organic content. The infaunal community is dominated by polychaetes from the Owenidae family, mainly represented by the specie Galathowenia oculata. - Group 2: occupies the sandy and low organic content sediments from the shallowest area of the Bank. Polychaetes are the most representative faunistic group, highlighting the dominance of the families Spionidae and Paraonidae. Prionospio fallax and Aricidea wassi are the most representative species of the group. - Group 3: situated in two deep areas in the south area of the Bank with muddy and high organic matter content sediments. It has the lowest infaunal abundance of the study, being dominated by the bivalve molluscs from the family Kelliellidae and by the annelids polychaetes from the family Paraonidae. - Group 4: Is the cluster that includes more stations in throughout the study. It is distributed spatially in the south area of the Bank, in different bathymetries, with the most heterogeneous sediments and moderate organic content. The bivalve molluscs from the Kelliellidae family again become dominant, with Kelliella miliaris reaching abundance over 7500 ind•m-2.IE

    Electrophysiological Heterogeneity of Fast-Spiking Interneurons: Chandelier versus Basket Cells

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    In the prefrontal cortex, parvalbumin-positive inhibitory neurons play a prominent role in the neural circuitry that subserves working memory, and alterations in these neurons contribute to the pathophysiology of schizophrenia. Two morphologically distinct classes of parvalbumin neurons that target the perisomatic region of pyramidal neurons, chandelier cells (ChCs) and basket cells (BCs), are generally thought to have the same "fast-spiking" phenotype, which is characterized by a short action potential and high frequency firing without adaptation. However, findings from studies in different species suggest that certain electrophysiological membrane properties might differ between these two cell classes. In this study, we assessed the physiological heterogeneity of fast-spiking interneurons as a function of two factors: species (macaque monkey vs. rat) and morphology (chandelier vs. basket). We showed previously that electrophysiological membrane properties of BCs differ between these two species. Here, for the first time, we report differences in ChCs membrane properties between monkey and rat. We also found that a number of membrane properties differentiate ChCs from BCs. Some of these differences were species-independent (e.g., fast and medium afterhyperpolarization, firing frequency, and depolarizing sag), whereas the differences in the first spike latency between ChCs and BCs were species-specific. Our findings indicate that different combinations of electrophysiological membrane properties distinguish ChCs from BCs in rodents and primates. Such electrophysiological differences between ChCs and BCs likely contribute to their distinctive roles in cortical circuitry in each species. © 2013 Povysheva et al

    Minimising multi-centre radiomics variability through image normalisation:a pilot study

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    Radiomics is an emerging technique for the quantification of imaging data that has recently shown great promise for deeper phenotyping of cardiovascular disease. Thus far, the technique has been mostly applied in single-centre studies. However, one of the main difficulties in multi-centre imaging studies is the inherent variability of image characteristics due to centre differences. In this paper, a comprehensive analysis of radiomics variability under several image- and feature-based normalisation techniques was conducted using a multi-centre cardiovascular magnetic resonance dataset. 218 subjects divided into healthy (n = 112) and hypertrophic cardiomyopathy (n = 106, HCM) groups from five different centres were considered. First and second order texture radiomic features were extracted from three regions of interest, namely the left and right ventricular cavities and the left ventricular myocardium. Two methods were used to assess features' variability. First, feature distributions were compared across centres to obtain a distribution similarity index. Second, two classification tasks were proposed to assess: (1) the amount of centre-related information encoded in normalised features (centre identification) and (2) the generalisation ability for a classification model when trained on these features (healthy versus HCM classification). The results showed that the feature-based harmonisation technique ComBat is able to remove the variability introduced by centre information from radiomic features, at the expense of slightly degrading classification performance. Piecewise linear histogram matching normalisation gave features with greater generalisation ability for classification ( balanced accuracy in between 0.78 ± 0.08 and 0.79 ± 0.09). Models trained with features from images without normalisation showed the worst performance overall (balanced accuracy in between 0.45 ± 0.28 and 0.60 ± 0.22). In conclusion, centre-related information removal did not imply good generalisation ability for classification

    Geomorphology of the Avilés Canyon System, Cantabrian Sea (BayofBiscay)

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    The Avilés Canyon System (ACS) is a complex, structurally-controlled canyon and valley system constituted by three main canyons of different morphostructural character. They are, from east to west: La Gaviera Canyon, El Corbiro Canyon and Avilés Canyon. In addition to this ACS, a new canyon has been surveyed: Navia Canyon. We present for the first time a high resolution multibeam map showing with great detail the morphological and structural complexity of this segment of the Cantabrian margin. ACS presents a tectonic imprint marked by NW-SE, NNE-SSW and E-W structures. The morphology of their reaches as well as their single mouth, in addition to some rock dredges in their major valleys, demonstrates active down-slope flushing. The continental shelf shows a flat, uniform slope with local and well defined rock outcrops south of Aviles Canyon head. Sedimentary zones are limited, showing thin unconsolidated sedimentary cover. Strong continental margin water dynamics avoid thicker sediment deposition, being littoral sedimentary dynamics responsible for transport to the canyons heads and conduit to the Biscay Abyssal plain. Biscay Abyssal Plain shows evidence of a strong westward current affecting the surveyed strip of this more than 10 km wide plain. Presence of two parallel deep sea channels, erosive scarps, and erosion of gully divides on the lower slope, may indicate that this is part of the distal fan at the termination of the large turbiditic system fed by Cap Ferret, Capbreton and other large canyons (Santander, Torrelavega, Lastres and Llanes) to the west of ACS.Instituto Español de OceanografíaVersión del edito
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