323 research outputs found

    Trophic indices for micronektonic fishes reveal their dependence on the microbial system in the North Atlantic.

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    This research was funded by projects BATHYPELAGIC (CTM2016-78853-R) from the Plan Estatal de I+D+I (Spain), SUMMER (Grant Agreement 817806) and TRIATLAS (Grant Agreement 817578), from the European Union (Horizon 2020 Research and Innovation Programme), and Grant Number IN607A2018/2 from the Axencia Galega de Innovación (GAIN, Xunta de Galicia, Spain).The importance of microbes for the functioning of oceanic food webs is well established, but their relevance for top consumers is still poorly appreciated. Large differences in individual size, and consequently in growth rates and the relevant spatial and temporal scales involved, make the integration of microorganisms and large metazoans in a common food web framework difficult. Using stable isotopes, this study estimated the trophic position of 13 species of micronektonic fishes to examine the microbial and metazoan contribution to mid trophic level consumers. Vertically migrant species displayed higher trophic positions than non-migrant species in all depth layers. The estimated trophic positions agreed well with those from the literature, but all species displayed mean increases between 0.5 and 0.8 trophic positions when taking into account microbial trophic steps. Trophic position, but not the relative importance of the microbial food web, increased with individual size, suggesting that current estimates of the trophic position of top consumers and of the length of oceanic food webs are too low because they are based only on metazoan trophic steps. This finding calls for a review of trophic position estimates and of the efficiency of trophic transfers along oceanic food webs.This research was funded by projects BATHYPELAGIC (CTM2016-78853-R) from the Plan Estatal de I+D+I (Spain), SUMMER (Grant Agreement 817806) and TRIATLAS (Grant Agreement 817578), from the European Union (Horizon 2020 Research and Innovation Programme), and Grant Number IN607A2018/2 from the Axencia Galega de Innovación (GAIN, Xunta de Galicia, Spain).En prensa2,92

    Diel-depth distributions of fish larvae off the Balearic Islands (western Mediterranean) under two environmental scenarios

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    Final workshop IDEADOS: The wrapping up of the IDEADOS project, International Workshop on Environment, Ecosystems and Demersal Resources and fisheries, 14-16 November 2012, Palma de Mallorca, SpainPeer reviewe

    Evaluación del comportamiento de las fábricas de ladrillos de tejar y argamasa debido a la humedad que asciende por capilaridad

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    For a better understanding of the behaviour of old brick masonry in facing the rising damp problem, multiple tests were made in the laboratory: water absorption, moisture content, apparent porosity, temperature and thermal camera imaging on brick masonry and its components: brick and mortar. This has allowed us to determine which of the previous tests is the best in predicting the behaviour of a real wall. In addition, the tests have also helped in defining a process to evaluate the moisture content of walls in a buildings, which is important for heritage restoration projects.Para un mejor conocimiento del comportamiento de las fábricas antiguas de ladrillo frente a la ascensión capilar de agua, se han realizado en laboratorio ensayos de absorción de agua, de contenido de humedad, de porosidad aparente, de temperatura e imágenes con cámara termográfica sobre muros de fábrica y sus materiales componentes: ladrillo y argamasa. Ello ha permitido inferir cuál es el ensayo realizado a los ladrillos que mejor predice el comportamiento del muro real. También ha permitido definir un procedimiento para evaluar el contenido de humedad de fábricas existentes, importante para los proyectos de restauración del patrimonio construido

    Are pelagic cephalopods in the Mediterranean as abundant as suggests the stomach contents of their predators?

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    Final workshop IDEADOS: The wrapping up of the IDEADOS project, International Workshop on Environment, Ecosystems and Demersal Resources and fisheries, 14-16 November 2012, Palma de Mallorca, SpainPeer reviewe

    Parental Involvement and Academic Performance of Students in Online Class Learning Modality

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    Parental involvement has long been an area of research across the world and is consistently found to have a positive effect on students’ academic performance. The global spread of COVID-19 pandemic, however, has caused disruptions in education systems worldwide including the Philippines, therefore, online education was implemented. During online distance learning, parents’ role in supervising their children’s education was reinforced and appeared to be crucial for some parents. The study used a sample of 49 parents of Grade 12 students at Lala National High School for the academic year 2022-2023. Results indicate a high level of parental involvement in terms of parenting, learning at home, decision making and familiarity with school information. The respondents also showed an outstanding performance during the course of the utilization of the online learning modalities. The study therefore concluded a positive correlation between parental involvement and the academic performance of students

    Dynamics of a Bioreactor with a Bacteria Piecewise-Linear Growth Model in a Methane-Producing Process

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    This paper shows a study, both analytical and numerical, of a continuous-time dynamical system associated with a simple model of a wastewater biorreactor. Nonsmooth phenomena and border-collision local bifurcations appear when the main parameters (dilution and biomass concentration at the inflow) are varied. We apply the Filippov methods following Kuznetsov’s work

    Structure and dynamics of cephalopod assemblages in the water column on shelf-break and slope grounds of the western Mediterranean

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    The structure and dynamics of cephalopod assemblages in different bathymetric strata from the surface to bottom grounds, down to a depth of 900 m, in the western Mediterranean, were analysed. Data were collected both on the shelf-break and slope during the summer and early autumn surveys, using a midwater trawl and a bottom trawl gear, to catch pelagic and nektobenthic species, respectively. The pelagic tows were not random, but targeted at the strongest and widest acoustic sound layers. A total of 26 cephalopod species belonging to 12 families were collected. With regard to the abundance, biomass and frequency of occurrence, we did not find a common seasonal trend for all the species, suggesting that their population dynamics are not governed by major environmental drivers. Most assemblage metrics (e.g., diversity, species richness, abundance and biomass) showed similar, low values in the pelagic layers compared to the bottom grounds. In general, assemblage metrics were lower in summer than in autumn on the shelf-break, while showing an inverse seasonal trend on the slope. There was a clear general increase in all metrics during the night compared to the day. Cluster results revealed differences in diel migratory strategies by stratum, vertical movements being scarce in the shelf-break species, but intense in the slope species.En prensa2,65

    Are pelagic cephalopods in the Mediterranean as abundant as suggests the stomach contents of their predators?

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    Final workshop IDEADOS: The wrapping up of the IDEADOS project, International Workshop on Environment, Ecosystems and Demersal Resources and fisheries, 14-16 November 2012, Palma de Mallorca, SpainPeer reviewe

    Nonlinear dynamics and bifurcation analysis in two models of sustainable development

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    We show in this document two mathematical models of development. Namely, we state two systems of nonlinear differential equations with state variables which regard to ecosystem, social and economic dimensions. We analyze nonlinear dynamics through bifurcation theory and state space simulations. Complex nonlinear systems including variables from ecosystem, social and economic dimensions show that, depending on the parameter values and initial conditions, different patterns can be obtained. Some of these patterns are related to fast decay of the exhaustible resources. Thus, also fast sustainable actions must be taken into account to prevent ecological disasters
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