425 research outputs found

    Condicionamientos ambientales de Erica Andevalensis Cabezudo & Rivera : respuesta frente a metales pesados

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    Se ha estudiado el contenido en metales de las distintas partes de Erica andevalensis (Cabezudo & Rivera) y se han caracterizado las aguas y los suelos de su entorno. Erica andevalensis es capaz de medrar en un medio extremadamente ácido, con suelos pobres y arenosos, y un elevado contenido en metales pesados, siendo su principal mecanismo de defensa la exclusión de los compuestos tóxicos por parte de las raíces y la posible precipitación de éstos en formas inertes, sea en la pared celular o en células determinadas. Queda excluida la probabilidad de hiperacumulación de los principales metales existentes en su entorno, pues en general muestras analizadas presentaron contenidos de metales en la parte aérea poco superiores a los considerados normales

    On the Integration of Wide Band-gap Semiconductors in Single Phase Boost PFC Converters

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    Alteraciones de la salud psicosocial en afectados por intoxicación por amianto

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    OBJETIVO Analizar el estado de salud psicosocial y mental de profesionales afectados por el amianto. MÉTODOS Estudio transversal con 110 profesionales en la comarca de Ferrolterra, España, afectadas por intoxicación por amianto; y un grupo de comparación de 70 trabajadores de astilleros, que no presentaban manifestación de enfermedades profesionales. Todos fueron del sexo masculino con edad promedio de 67 años. El estudio se llevó a cabo entre Enero y Junio de 2013. Para la realización de la investigación se empleó como instrumento el cuestionario SCL-90 de Derogatis. Este cuestionario está formado por nueve variables que miden la sintomatología psicosomática, y también, se calculó un índice global de gravedad psicosomática. Se les preguntó a los sujetos sobre su percepción global de sentirse bien. Se analizaron los datos mediante la técnica del Anova, y se realizó una regresión logística. RESULTADOS Los sujetos afectados por la intoxicación por amianto presentaron altos índices de alteración de su salud psicológica en variables como somatización, obsesión-compulsión, sensibilidad interpersonal, depresión, ansiedad, hostilidad, ansiedad fóbica, ideación paranoide, psicoticismo e indicador global de gravedad. CONCLUSIONES La interacción social como factor diferenciador entre trabajadores afectados por síndromes crónicos, debidos al trabajo, frente a los no afectados, permitirá desarrollar programas de intervención basados en el fomento de la red social de los afectados.OBJECTIVE To analyze the state of psychosocial and mental health of professionals affected by asbestos. METHODS A cross-sectional study was conducted with 110 professionals working in the Ferrolterra region of Spain, who were affected by asbestos poisoning. This group was compared with a group of 70 shipyard workers with no manifestation of work-related diseases. All the participants were male with a mean age of 67 years. This study was conducted in 2013, between January and June, and used the SCL-90 questionnaire by Derogatis as its primary measure for research. This questionnaire consists of 9 variables that measure psychosomatic symptoms. In addition, an overall index of psychosomatic gravity was calculated. The participants were also asked two questions concerning their overall perception of feeling good. Data were analyzed by ANOVA and logistic regression. RESULTS Participants affected by asbestos poisoning showed high occurrence rates of psychological health variables such as somatization, obsessive-compulsive, interpersonal sensitivity, depression, anxiety, hostility, phobic anxiety, paranoid ideation, psychoticism, and global severity index. CONCLUSIONS Social interaction as a differentiating factor between workers affected by work-related chronic syndromes as compared to healthy participants will possibly aid in the development of intervention programs by improving the social network of affected individuals.OBJECTIVE To analyze the state of psychosocial and mental health of professionals affected by asbestos. METHODS A cross-sectional study was conducted with 110 professionals working in the Ferrolterra region of Spain, who were affected by asbestos poisoning. This group was compared with a group of 70 shipyard workers with no manifestation of work-related diseases. All the participants were male with a mean age of 67 years. This study was conducted in 2013, between January and June, and used the SCL-90 questionnaire by Derogatis as its primary measure for research. This questionnaire consists of 9 variables that measure psychosomatic symptoms. In addition, an overall index of psychosomatic gravity was calculated. The participants were also asked two questions concerning their overall perception of feeling good. Data were analyzed by ANOVA and logistic regression. RESULTS Participants affected by asbestos poisoning showed high occurrence rates of psychological health variables such as somatization, obsessive-compulsive, interpersonal sensitivity, depression, anxiety, hostility, phobic anxiety, paranoid ideation, psychoticism, and global severity index. CONCLUSIONS Social interaction as a differentiating factor between workers affected by work-related chronic syndromes as compared to healthy participants will possibly aid in the development of intervention programs by improving the social network of affected individuals

    The evolution of gigantism in active marine predators

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    A novel hypothesis to better understand the evolution of gigantism in active marine predators and the diversity of body sizes, feeding strategies and thermophysiologies of extinct and living aquatic vertebrates is proposed. Recent works suggest that some aspects of animal energetics can act as constraining factors for body size. Given that mass-specific metabolic rate decreases with body mass, the body size of active predators should be limited by the high metabolic demand of this feeding strategy. In this context, we propose that shifts towards higher metabolic levels can enable the same activity and feeding strategy to be maintained at bigger body sizes, offering a satisfactory explanation for the evolution of gigantism in active predators, including a vast quantity of fossil taxa. Therefore, assessing the metabolic ceilings of living aquatic vertebrates and the thermoregulatory strategies of certain key extinct groups is now crucial to define the energetic limits of predation and provide quantitative support for this model

    Patterns of ecological diversification in thelodonts

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    Here we explore the spatial, temporal and phylogenetic patterns of ecological diversification for the entire clade of thelodonts, one of the earliest groups of vertebrates and longest lasting of the Palaeozoic agnathans in the fossil record. Parsimony and maximum-likelihood methods are used to reconstruct ancestral states of their geographical distributions, habitats and lifestyles. Our results support the concept that thelodonts originated during the Middle?-Late Ordovician probably in marine open waters of Laurasia, with a demersal lifestyle on hard substrates being the ancestral condition for the whole clade. Later, thelodonts underwent a complex ecological diversification and palaeobiogeographical history, comparable in many aspects to those of some major groups of living fishes. Different modes of life evolved repeatedly and a wide range of habitats were colonized by distinct groups, including deep waters and brackish marine and/or freshwater environments. Diadromous strategies presumably appeared on nine different occasions. The palaeobiogeographical history of thelodonts reveals significant differences in the dispersal potential of some major groups. Dispersal of thelodontiforms entailed displacements over long distances and the crossing of deep-water biogeographical barriers, whereas those of furcacaudiforms were always limited to areas interconnected by shallow platforms. We propose that the evolution of pelagic larval stages in thelodontiforms might explain this biogeographical pattern and could satisfactorily account for the greater evolutionary success of this group

    Ecomorphological inferences in early vertebrates: Reconstructing Dunkleosteus terrelli (Arthrodira, Placodermi) caudal fin from palaeoecological data

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    Our knowledge about the body morphology of many extinct early vertebrates is very limited, especially in regard to their post-thoracic region. The prompt disarticulation of the dermo-skeletal elements due to taphonomic processes and the lack of a well-ossified endoskeleton in a large number of groups hinder the preservation of complete specimens. Previous reconstructions of most early vertebrates known from partial remains have been wholly based on phylogenetically closely related taxa. However, body design of fishes is determined, to a large extent, by their swimming mode and feeding niche, making it possible to recognise different morphological traits that have evolved several times in non-closely related groups with similar lifestyles. Based on this well-known ecomorphological correlation, here we propose a useful comparative framework established on extant taxa for predicting some anatomical aspects in extinct aquatic vertebrates from palaeoecological data and vice versa. For this, we have assessed the relationship between the locomotory patterns and the morphological variability of the caudal region in extant sharks by means of geometric morphometrics and allometric regression analysis. Multivariate analyses reveal a strong morphological convergence in non-closely related shark species that share similar modes of life, enabling the characterization of the caudal fin morphology of different ecological subgroups. In addition, interspecific positive allometry, affecting mainly the caudal fin span, has been detected. This phenomenon seems to be stronger in sharks with more pelagic habits, supporting its role as a compensation mechanism for the loss of hydrodynamic lift associated with the increase in body size, as previously suggested for many other living and extinct aquatic vertebrates. The quantification of shape change per unit size in each ecological subgroup has allowed us to establish a basis for inferring not only qualitative aspects of the caudal fin morphology of extinct early vertebrates but also to predict absolute values of other variables such as the fin span or the hypocercal and heterocercal angles. The application of this ecomorphological approach to the specific case of Dunkleosteus terrelli has led to a new reconstruction of this emblematic placoderm. Our proposal suggests a caudal fin with a well-developed ventral lobe, narrow peduncle and wide span, in contrast to classical reconstructions founded on the phylogenetic proximity with much smaller placoderms known from complete specimens. Interestingly, this prediction gains support with the recent discovery of fin distal elements (ceratotrichia) in a well preserved D. terrelli, which suggests a possible greater morphological variability in placoderm caudal fins than previously thought

    Holothuria tubulosa as a bioindicator to analyse metal pollution on the coast of Alicante (Spain)

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    Metal pollution is a major concern worldwide. The concentration of several metals in marine sediments from Alicante, Spain (Western Mediterranean): Cabo de la Huerta, Albufereta, San Gabriel and Cabo de Santa Pola has been studied, being areas with contrasted metal stress due to anthropogenic pressures, and their bioaccumulation in different tissues of Holothuria tubulosa (body wall, guts and intestine). The metals with more different levels among samples were Fe, Al, V, Mn, Pb, Ga, As, Cr, Zn and B. The body wall was the tissue that showed a significantly different signature of metal levels compared to the other body parts and the sediment. The guts, followed by the intestines, were the tissues with greatest bioaccumulation. The standard guidelines for safety limits (US EPA) for As, Cr, Pb and Zn are in the range “non-polluted”. In all the areas, the quality guidelines for Effect Level, Probable Effect Level, Effect Range Low and Effect Range Medium for As, Cr, Pb and Zn are much lower than those established, indicating no biologically adverse effects resulting from exposure to these metals. Regarding the potential ecological risk, for all metals it is <40 with low risk in all zones. The metals studied present a negative Igeo (area not contaminated). Arsenic in Albufereta and strontium in all the areas studied are the only ones that present a level 2 (uncontaminated to moderately contaminated). The Enrichment Factor (EF), with Fe as the normalising element, had a level 1–3 (minor enrichment), with the exception of Pb, B, As and Sr. Despite the concentrations in sediments being lower compared with other parts of the world, the Biota-Sediment Assimilation Factor from the body wall was higher at As (9.2) and B (7.3). It is necessary to highlight the high levels of As in the body wall (17 to 23 mg/kg of dry material), this is surprising, and it seems to be a general trend throughout the world.The authors wish to thank the Generalitat Valenciana (Spain) for the financial help of the Project CIAICO/2021. This study was partially financed by the University of Alicante’s Chemical Engineering Department, Marine Sciences & Applied Biology Department and University Institute of Water and Environmental Sciences (IUACA)

    New Physics hints from τ\tau scalar interactions and (g2)e,μ(g-2)_{e,\mu}

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    We consider a flavour conserving two Higgs doublet model that consists of a type I (or X) quark sector and a generalized lepton sector where the Yukawa couplings of the charged leptons to the new scalars are not proportional to the lepton masses. The model, previously proposed to solve both muon and electron g2g-2 anomalies simultaneously, is also capable to accommodate the ATLAS excess in ppSτ+τpp \rightarrow S \rightarrow \tau^{+}\tau^{-} with gluon-gluon fusion production in the invariant mass range [0.2; 0.6] TeV, including all relevant low and high energy constraints. The excess is reproduced taking into account the new contributions from the scalar H, the pseudoscalar A, or both. In particular, detailed numerical analyses favoured the solution with a significant hierarchy among the vevs of the two Higgs doublets, tβ10t_{\beta} \sim 10, and light neutral scalars satisfying mA>mHm_\mathrm{A} > m_\mathrm{H} with sizable couplings to τ\tau leptons. In this region of the parameter space, the muon g2g-2 anomaly receives one and two loop (Barr-Zee) contributions of similar size, while the electron anomaly is explained at two loops. An analogous ATLAS excess in bb-associated production and the CMS excess in ditop production are also studied. Further New Physics prospects concerning the anomalous magnetic moment of the τ\tau lepton and the implications of the CDF MWM_W measurement on the final results are discussed.Comment: 25 pages, 8 figures, 5 tables. Matches published versio

    The role of desalination in water management in Southeast Spain

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    The aim of this paper is to evaluate the importance of seawater desalination to the supply of fresh water to SE Spain, in order to tackle the problem of the shortage of water resources. The Mancomunidad de los Canales del Taibilla (MCT) supplies water to a population of more than 2,400,000 inhabitants in SE Spain. Resources managed by the MCT include the Taibilla river basin, water from the Tajo-Segura transfer, other unusual occasional groundwater contributions and from 2003, sea water desalination. Four desalination plants: Alicante I and II and San Pedro del Pinatar I and II together with resources from other desalination plants provide a significant amount of resources. For a decade (2004-2013) the resources coming from sea water desalination averaged 20.2% of all the resources used by MCT, with 432 Mm3 of total production in the period studied. However, the yearly contribution of desalination has changed depending on the availability of other resources. Moreover, seawater desalination has been essential to ensure water supply in the Alicante and Murcia areas. This resource has been important in periods of shortage, but also in unusual exploitation situations, such as that of the post-transfer tunnel detachment, which was classified as the most important breakdown of this infrastructure within its long lifetime. Moreover, scenarios of future climate changes could increase demands for water supply.Ministerio de Economía y Competitividad (Spanish government), for the financial aid with Project CTM2013-46669-R

    Network dynamics of eukaryotic LTR retroelements beyond phylogenetic trees

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    <p>Abstract</p> <p>Background</p> <p>Sequencing projects have allowed diverse retroviruses and LTR retrotransposons from different eukaryotic organisms to be characterized. It is known that retroviruses and other retro-transcribing viruses evolve from LTR retrotransposons and that this whole system clusters into five families: <it>Ty3/Gypsy, Retroviridae, Ty1/Copia, Bel/Pao </it>and <it>Caulimoviridae</it>. Phylogenetic analyses usually show that these split into multiple distinct lineages but what is yet to be understood is how deep evolution occurred in this system.</p> <p>Results</p> <p>We combined phylogenetic and graph analyses to investigate the history of LTR retroelements both as a tree and as a network. We used 268 non-redundant LTR retroelements, many of them introduced for the first time in this work, to elucidate all possible LTR retroelement phylogenetic patterns. These were superimposed over the tree of eukaryotes to investigate the dynamics of the system, at distinct evolutionary times. Next, we investigated phenotypic features such as duplication and variability of amino acid motifs, and several differences in genomic ORF organization. Using this information we characterized eight reticulate evolution markers to construct phenotypic network models.</p> <p>Conclusion</p> <p>The evolutionary history of LTR retroelements can be traced as a time-evolving network that depends on phylogenetic patterns, epigenetic host-factors and phenotypic plasticity. The <it>Ty1/Copia </it>and the <it>Ty3/Gypsy </it>families represent the oldest patterns in this network that we found mimics eukaryotic macroevolution. The emergence of the <it>Bel/Pao, Retroviridae </it>and <it>Caulimoviridae </it>families in this network can be related with distinct inflations of the <it>Ty3/Gypsy </it>family, at distinct evolutionary times. This suggests that <it>Ty3/Gypsy </it>ancestors diversified much more than their <it>Ty1/Copia </it>counterparts, at distinct geological eras. Consistent with the principle of preferential attachment, the connectivities among phenotypic markers, taken as network-represented combinations, are power-law distributed. This evidences an inflationary mode of evolution where the system diversity; 1) expands continuously alternating vertical and gradual processes of phylogenetic divergence with episodes of modular, saltatory and reticulate evolution; 2) is governed by the intrinsic capability of distinct LTR retroelement host-communities to self-organize their phenotypes according to emergent laws characteristic of complex systems.</p> <p>Reviewers</p> <p>This article was reviewed by Eugene V. Koonin, Eric Bapteste, and Enmanuelle Lerat (nominated by King Jordan)</p
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