152 research outputs found

    Inversion tectonique de la marge nord du Bassin basque-cantabrique

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    Nervous Necrosis Virus (NNV) Booster Vaccination Increases Senegalese Sole Survival and Enhances Immunoprotection

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    iral encephalopathy and retinopathy (VER), caused by nervous necrosis virus (NNV), is a serious threat to Senegalese sole farming. We have previously demonstrated that immunization with an inactivated vaccine confers partial protection against the infection. However, a vaccination program must be finely adjusted to achieve the best results in terms of immune system stimulation and protection. In this study we show that a booster injection 30 days after prime vaccination increases sole survival and reduces NNV replication in brain (viral target organ). The analysis of immune-related genes expression indicated that T CD4+ lymphocytes and the proteins Mx and HERC4 may play an important role in the protection. These findings increase our understanding of sole immune response against NNV and may contribute to the development of effective protection measures.This research was funded by Ministerio de Ciencia, Innovación y Universidades (MCIUI), the Agencia Estatal de Investigación (AEI) and FEDER, grant number RTI2018-094687-B-C21. Dr. Sandra Souto was funded with a postdoctoral grant from Consellería de Cultura, Educación e Universidade, Xunta de Galicia (grant number: ED481D-2022-024). Partial funding for open access charge: Universidad de Málag

    Mapping paleoflooded areas on evaporite playa deposits over sandy sediments (Tablas de Daimiel, Spain) using hyperspectral DAIS 7915 and ROSIS spectrometer data

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    Open-system lakes developing marshes are sensitive environments to climate changes. Mineralogical climate markers such as gypsum and dolomitized carbonate are spatialy traced using hyperspectral imagery. Climate-dependent saline soils, carbonate, organic matter and iron oxide crusts have been mapped along different stages of flooding and emersion in the past 2000 years using DAIS and ROSIS spectrometer data. Spectral behaviour interacting and masking from various mineralogical components are described on laboratory spectra. Influence of landuse on the spatial spectral behaviour of paleoenvironments is discussed. A general outline of the past pools is drawn on the area surrounding the actual marsh, providing priceless data to use in further paleoclimate limnological research and in the development of new techniques for that research

    Ignition and combustion of single particles of coal and biomass under O2/CO2 atmospheres

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    Biomass energy with carbon dioxide capture and storage (CCS) technologies like oxy-fuel is the only way to achieve net removal of CO2 from the atmosphere in power generation. A single particle apparatus has been developed for rapid heating and combustion of individual fuel particles in air or O2/CO2 atmospheres. This wire mesh apparatus was used as a heating element to heat the particle by radiation while optical access allowed particle combustion characterization by high speed camera recording. Four different biomass and a bituminous coal were used in air and 21, 30 and 40% O2 atmospheres with balance of CO2. High speed video image analysis showed differences in ignition and devolatilization behaviour. The influence of particle size and mass on burnout times was higher in the coal, while biomass particle size can have a greater range of sizes for the same burnout times. The 30%O2 atmosphere was enough to have less burnout time than in air atmosphere for all the samples. During biomass particle combustion, the results showed that the surface tension on the biomass char particle plays a significant role due to partial melting of the char particle. This effect modifies the char particle shape during its combustion, with particles becoming more spherical particle even for those that initially had a fibrous shape

    Mapping of semi-arid iron bearing red sands on emerged areas around lake marshes (Tablas de Daimiel, Spain) using hyperspectral DAIS 7915 spectrometer data

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    Wetlands are particularly sensitive environments receiving attention from the natural sciences community due to their wealth of both flora and fauna, and often considered as natural parks. In the Tablas de Daimiel (La Mancha, Central Spain), Digital Airborne Imaging Spectrometer data (DAIS 7915) have been analyzed to map geological processes on areas around the receding wetland which have never been flooded by water in the past. Sediments permanently exposed to the atmosphere dehydrate and oxide, developing different mineralogical associations arranged on planation surfaces. Such planation surfaces are key in the geological knowledge of recent climate change and landscape evolution. Progressive iron oxide/hydroxide rate and decarbonation can be spectrally followed on the Holocene sands framing the current marshy area. Such mineralogical changes are geologically registered on flat surfaces at different heights over the receding shore of the paleolake. Interacting erosion and sedimentation processes are responsible for the development of the flat morphological surfaces with increasing dryness. Maps are built for four different morphological units consisting of planation surfaces following chronologically the receding marsh during the last 2000 years before the present. Interactive spectral responses of mineralogical associations are described on the imagery, field and laboratory spectra

    Comparative gene expression of gonadotropins (FSH and LH) and peptide levels of gonadotropin-releasing hormones (GnRHs) in the pituitary of wild and cultured Senegalese sole (Solea senegalensis) broodstocks

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    12 páginas, 8 figuras, 2 tablas.The Senegalese sole (Solea senegalensis) is a valuable flatfish for aquaculture, but it presents important reproductive problems in captivity. Spawning is achieved by wild-caught breeders but cultured broodstocks fail to spawn spontaneously and, when they do, eggs are unfertilized. To gain knowledge on the physiological basis underlying this reproductive dysfunction, this study aimed at analyzing comparative hormone levels between wild and cultured broodstocks at the spawning season. The Senegalese sole gonadotropin (GTH) subunits, FSHβ, LHβ and GPα, were cloned and qualitative (in situ hybridization) and quantitative (real-time PCR) assays developed to analyze pituitary GTH gene expression. In females, FSHβ and GPα mRNA levels were higher in wild than in cultured broodstocks, whereas in males all three subunits were highest in cultured. By ELISA, three GnRH forms were detected in the pituitary, displaying a relative abundance of GnRH2 > GnRH1 > GnRH3. All GnRHs were slightly more abundant in wild than cultured females, whereas no differences were observed in males. Plasma levels of vitellogenin and sex steroids were also analyzed. Results showed endocrine differences between wild and cultured broodstocks at the spawning period, which could be related to the endocrine failure of the reproductive axis in cultured breeders.This research was funded by the Spanish Ministry of Education and Science (MEC) (AGL2006-13777-C01), the Ministry of Agriculture, Fisheries and Food (MAPA) (JACUMAR, II National Plan for the Cultivation of Sole) and the Regional Government of Galicia (PGIDIT06RMA004E). J.M. Guzmán received a FPI fellowship from the MEC. J.B. Ortiz-Delgado was supported by the “Ramón y Cajal” program (MEC, Spain).Peer reviewe

    Stability Loss in Quasilinear DAEs by Divergence of a Pencil Eigenvalue

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    Single particle flame-combustion studies on solid biomass fuels

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    Combustion of solid biomass in large scale power generation has been recognized as a key technology for the transition to a decarbonized electricity sector in the UK by 2050. Much of the near-term forecast capacity is likely to be by the conversion of existing coal-fired pulverized fuel plant (DECC, 2012). In such applications, it will be necessary to ensure that the combustion behaviour of the solid biomass fuels is engineered to match, as far as practical, that of the original plant design. While biomass feedstock characteristics vary considerably, one controllable variable for pulverized fuel is the size of the particles.Useful modelling for adaptation and design of boiler plant can be improved with more detailed measurement of the real behaviour of individual particles of the varying fuels. Typical power plant biomass fuels including pine, eucalyptus and willow with particle sizes ranging from up to 3. mm (Van Loo and Koppejan, 2008) and with differing moisture content and aspect ratios were selected for study. Single particles were supported in a water-cooled cover and then exposed above a flame, simulating biomass combustion in a furnace. Measurements of ignition delay, volatile burning time and char burn-out time were undertaken using high speed image capture. Temperatures of the surrounding environment and near to the particle surface were measured with thermocouples and thermometric imaging. Thermo-gravimetric measurements on separate samples complement the single particle measurements as a means of verifying the demarcation between the different stages of combustion and providing kinetic data.Analysis of the data identified correlations between the biomass fundamental characteristics, particle size, and the observed combustion profiles. Empirical expressions for the duration of each combustion stage have been derived. These have been validated with basic modelling including the predicted devolatilisation stage calculated by the FG-Biomass model (Chen et al.,1998)

    Normal forms and internal regularization of nonlinear differential-algebraic control systems

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    In this article, we propose two normal forms for nonlinear differential-algebraic control systems (DACSs) under external feedback equivalence, using a notion called maximal controlled invariant submanifold. The two normal forms simplify the system structures and facilitate understanding the various roles of variables for nonlinear DACSs. Moreover, we study when a given nonlinear DACS is internally regularizable, that is, when there exists a state feedback transforming the DACS into a differential-algebraic equation (DAE) with internal regularity, the latter notion is closely related to the existence and uniqueness of solutions of DAEs. We also revise a commonly used method in DAE solution theory, called the geometric reduction method. We apply this method to DACSs and formulate it as an algorithm, which is used to construct maximal controlled invariant submanifolds and to find internal regularization feedbacks. Two examples of mechanical systems are used to illustrate the proposed normal forms and to show how to internally regularize DACSs
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